threatened species occurs on John F. Kennedy. Space. Center/Merritt. Island. National. Wildlife. Refuge. ... recovery strategy was developed, based on studies of Florida. Scrub-Jays and scrub vegetation. ..... Administration. (NASA),. U.S. Fish.
r/
j
NASA-TM-111676
A Conservation Strategy for the Florida Scrub-Jay on John F. Kennedy Space Center/ Merritt Island National Wildlife Refuge: An Initial Scientific Basis for Recovery
D. R. Breininger, F. Adrian
April
V. L. Larson,
and H. Hill,
1996
Jr.
R. Schaub,
B. W. Duncan,
P. A. Schmalzer,
D. M. Oddy,
R. B. Smith,
NASA-TM-111676
A Conservation Strategy for the Florida Scrub -- Jay on John F. Kennedy Space Center/ Merritt Island National Wildlife Refuge: An Initial Scientific Basis for Recovery
D. R. Breininger, V. L. Larson, R. Schaub, B. W. Duncan, P. A. Schmalzer, D. M. Oddy, R. B. Smith Dynamac Corporation, NASA Biomedical Operations Office John F. Kennedy Space Center, Florida F. Adrian and H. Hill, Jr. U.S. Fish and Wildlife Service, Merritt Titusville, Horida
Island National Wildlife Refuge
National Aeronautics and Space AdmLrus"tration John F. Kennedy Space Center, Kennedy Space Center, Florida
April
1996
32899-0001
Abstract
The ecosystem
fire.
F. Kennedy trends
on reproduction
been
Analyses declining
scrub,
of the largest
Population
1995.
(Aphelocoma
of Florida
One
on John
Refuge. data
Scrub-Jay
integrity
frequent occurs
Florida
were
for 30 years. declined
10 years,
management
simulations
suggest
the jay population responsible natural
fire regimes.
recovery scrub
to persist.
for declining
strategy
vegetation.
science
principles
to restore
habitat,
habitat
A reserve for scrub
quality.
Site-specific
fire alone
can not reverse on studies
was formulated The
mechanical areas
tree
greatly
from optimal
with
the disruption
the trajectories. Scrub-Jays
of A
and
on conservation
cutting
for severely
degraded
for population
for
structure,
frequent
rapid
in
and computer
emphasizes
can produce
2
40%
strategy
will need to be developed, suitable
by another
of Florida based
has
suggested
of vegetation
are associated
ecosystems.
strategies conditions
trajectories
based
large
deviate
1988 -
suitability
Data
suitability,
design
but includes across
cannot
Landscape
was developed,
Pine thinning
to achieve
suitability
and field
from
simulations
and will decline
species
Wildlife
collected
intensified.
requires
modeling
that habitat
and computer
is not greatly
Prescribed
areas.
modified
data
of
threatened
population
indicated
that
National
Scrub-Jays
by at least 40%
that habitat
Island
using
of Florida
Field
that the population
of this federally
predicted
photography
is an indicator
ecosystem
Center/Merritt
and survival
if habitat
an endangered
populations
Space
of historical
coerulescens)
increases monitored,
persistence.
fire
in habitat and
Table
of Contents
Abstract
2
List of Tables
5 6
List of Figures Executive
8
Summary
13
Acknowledgments 1.0
14
Introduction
1.1
Optimal
Florida
Scrub-Jay
1.1.1 1.1.2
Landscape Characteristics Focal Habitat Patches
1.1.3
Matrix
1.2 2.0
Past
2.1
Risk
Management
Happy
Creek
2.2.3
Titan Complex Shiloh and Haulover
and
National
Estimated Extinction
Population Risk Change
Canal
31
Seashore
33 34
and Declines
2.3.3
Loss
of Natural
Happy
33
Declines
Replacement of Scrub Increased Forestation
Habitat
24
Risks
3O
2.3.1 2.3.2
2.3.4.2
Extinction
29
Canaveral
Landscape
21
26
in Habitat
with Urban
Openings
2.3.4 Historic Landscape 2.3.4.1 Tel 4
2.4
Status
21
2.2.2
2.3
and Habitat
Assessments Trajectories
2.2.7
20
Overview
Population
Population 2.2.1 Tel 4
2.2.6
19 19
Scrub-Jay
2.2
2.2.4 2.2.5
17
Habitat
Habitat
Florida
15
Habitat
36 36
Areas
38 Among
Scrub
Oaks
38 39
Change
40 44
Creek
Restoration
Suitability
and Population
Recovery
3
52
3.0 Strategic
Recovery
Plan
58
3.1
58
Criteria of Reserve Design 3.1.1 Provide for a Large Population 3.1.2 Maintain the Northern and Southern 3.1.3
Maintain
3.1.4
Minimize
Edge
by Keeping
3.1.5
Maximize
Well
Drained
3.1.6
Keep
3.1.7
Maximize
3.2
the Population
Patches
Habitat
Biogeographical
3.2.1
Population
3.2.2
Linkages
3.3 Restoration
in Close
60
Wide
but Maintain
the Necessary
and Minimize
Restoration
Costs
Degraded
63
Burning
69
Techniques
70 72
Habitat
3.7
Ecosystem
3.8
Long-term
Habitat
and Restoration
72
Costs
75
Inventory
Shiloh
3.6
62 63
Quality
3.5.1
61
69
Burning
Population
Matrix
62
Proximity
Activities
Restoration
Appendix
60
67
3.3.2
3.5
Landscapes
Centers
and
3.4.1
Areas
of the Population
Considerations
Mechanical
Habitat
Extent Contiguous
Reserve
Scrub
Quality
3.3.1
3.4
in Large,
59 59
and Haulover
Population
76
Inventory
79
Management
80
Management
82
Monitoring
A: Description
of the John
F. Kennedy
Space
Center
85
A.1 Landscape A.2 Climate
85
A.3 History A.4 Habitat
86
86 87
Descriptions
89
Appendix
B:
Fire
Appendix
C:
Ecosystem
Integrity
Appendix
D:
Population
Risk
Appendix
E:
Other
Literature
Management
Florida
and Biological
Diversity
91 94
Model
Scrub-Jay
Studies
Cited
95 97
4
List of Tables
Table
1. Current
Scrub
Reserve
Table
2.
Scrub
Reserve
Table
3.
Shiloh
land cover Units
Disturbed
Scrub
and corridors
and degraded
Units
Florida
(SRUs)
composition
(SRUs)
Scrub-Jay
Reserve
habitat
and corridors
groups
(hectares)
of the
between
SRUs.
(hectares)
within
between
SRUs.
and habitat
Unit and Haulover
by burn unit
corridor.
5
64
72
in the 78
List of Figures Figure
1.
Boundaries
Merritt
Island
of John
National
F. Kennedy
Wildlife
Refuge,
Canaveral
Figure
2.
Florida
Scrub-Jay
study
Figure
3.
Florida
Scrub-Jay
population
Figure
4.
Population
Figure
Figure
trajectories
data
6.
from
data
Haulover
Seashore,
A) Titan
launch
complexes,
of population
probabilities
Figure
8.
Comparative
extinction
Figure
9.
Historical
success
reproductive
National
Comparative
25
habitat. and
28
Creek.
and C) Canaveral
7.
and
Archbold
reproductive
using
Figure
success
B) unburned
A) Tel 4 and B) Happy
from
23
model.
reproductive
using
trajectories
areas,
22 risk
and
trajectories
Population
survival
National
areas.
using
A) optimal
Population
survival
Canaveral
including
Air Station.
data from
5.
Center,
16
and Cape
survival
Space
success B) Shiloh
and and 32
Seashore.
35
declines.
37
risk estimates.
landscapes
mapped
using
aerial
photographs
at Tel 4. Figure
10.
41 The
Kennedy Figure
11.
Space Forest
Tel 4 study Figure
12.
The
Kennedy Figure
13.
14.
15.
Kennedy
The
dynamics
on previously Space
of forest
site on
cleared
areas
in the 43
Center.
in the Tel
4 study
site on 45
Center. landscape
dynamics Space
patterns
mapped
using
aerial 46
Creek. of open
scrub
in the Happy
Creek
study
site 48
Center.
dynamics
Space
in the Tel 4 study
42
site on Kennedy
at Happy
The
scrub
Center.
Historical
on Kennedy Figure
of open
establishment
Space
photographs Figure
dynamics
of forest
in the Happy
Creek
study
site on 5O
Center.
6
Figure 16. Forest establishment on previously cleared areas in the Happy Creek study site on Kennedy Space Center.
51
Figure 17. Influence of habitat, helpers, and epidemics on population trajectories in habitat capable of supporting 700 53
breeding pairs after restoration. Figure 18. Reduction of extinction risk associated with restoration.
54
Figure 19. Influence of initial population size and habitat suitability 56
on extinction risk. Figure 20. Influence of initial population size and hurricanes on
57
extinction risk in optimal habitat. Figure 21. Potential scrub habitat on John F. Kennedy Space Center/Merritt Island National Wildlife Refuge, Cape Canaveral Air Station, and adjacent lands.
65
Figure 22. Scrub Reserve Units (SRUs) and corridors.
66
Figure 23. Disturbed and degraded scrub.
74
Figure 24. Bald Eagle nest sites on John F. Kennedy Space Center/Merritt Island National Wildlife Refuge.
7
81
Executive
The peninsular
Florida
Scrub-Jay
(Aphelocoma
portion
of Florida.
It was listed
Fish and Wildlife species John
Service
imperiled
status
F. Kennedy
Space
remaining
population
managed Some
habitat
Canaveral
Canaveral/Merritt
The
Scrub-Jay
to formulate scrub
for the Florida inventories required
are needed
KSC/MINWR the scrub
Florida
recovery
provides
recovery
Scrub-Jay
to as the Cape
review
recovery
to KSC/MINWR.
in the and 2)
towards
and the
and biological Detailed
plans,
Implementation
population
with
on KSC/MINWR,
site-specific
will lead
by the
for a large
the decline
and recovery.
efforts.
(MINWR).
of the jay population
a detailed
is
is contiguous
is specific
quality
habitat
(CNS)
has potential
decline
this document
and survival
jays on KSC/MINWR,
quantify
population
resulted
in declining
habitat
towards
on
basis
habitat
but are not
of the stabilizing
and will improve
the
the overall
quality
of
ecosystem.
Reproductive banded
many
population
1 ) to describe
habitat
to develop
from
are:
population
Seashore
document
Scrub
Refuge
can be referred
and scrub
document
Scrub-Jay
recommendations
This
KSC
Wildlife
also
for this
for one of the three
National
which
reasons
Most
National
areas
ecosystem.
strategy
The
to initiate
(CCAS), These
population
habitat
KSC/MINWR
of this document
a general
ecosystem.
The
population.
purposes
Island
by the U.S.
degradation.
Scrub-Jay.
as Canaveral
(NPS).
Island
and habitat
only in the
species
The primary
provides
of the Florida
as Merritt
occurs
as a threatened
in 1987.
(KSC)
Air Station
Scrub-Jay
Florida
Center
managed
Service
coerulescens)
are loss of habitat
cores
is also
Park
the Cape Florida
(USFWS)
by the USFWS
National
Summary
models
trends Florida
data,
were
seven
incorporated
and extinction Scrub-Jay
and photointerpretation
from
risks. habitat
years
of study of color
into a population Landscape suitability
of historical
changes were
and recent
risk
model
that
evaluated photography.
using
to
Most of the KSC/MINWR Florida Scrub-Jay population has been declining for at least 10 years and is expected to decline by 40% within The
KSC/MINWR
population
and population Scrub-Jay scrub
trajectories
species. fires
species
Nearly to maintain
( Gopherus
coupen),
Florida
Loggerhead
Extinction
of these
regional,
and global
Prior
Shrike
species
with short
agricultural
practices
resulted
established
in many
agricultural
becoming 1960s.
forests The
1960s
and most
seedlings loads
open
this time,
sandy
increased.
became
frequent
Fires
established
increased,
resulting
fires
areas
would
Frog
(Rana
capito
species.
impact
on local,
is the largest
kept KSC/MINWR
of marshes
differed
were
from
fire patterns.
led to increased
Fire suppression patches
in scrub
no longer
in high densities in the potential
of scrub
became
caused
occurred
pine mortality, in areas
sites
burned
poorly,
agencies
in the
habitat during
Shrub
the became
height
and pine
with soil disturbance.
for catastrophic
the
by having
and marsh
closed.
became
However,
areas
by federal
Early
species
abandoned.
Disturbed
program
many
plant
undisturbed
of KSC/MINWR
an open
and scrub.
Native
after they
of the space
During
Gopher
corias
coast.
areas
and facilities.
habitat
(Drymarchon
KSC/MINWR
in soil disturbance.
to acquisition
by roads
pine densities
Fuel
prior
because
no scrub
on the Gopher
and other
concern
characteristic
that influenced
and 1970s.
forests,
vegetation
development
fragmentation
Atlantic
and composition
fuels
impacts
Snake
Florida other
and marshes;
negative
Florida
The
require
long unburned
Indigo
if habitat
for many
concern
scrub
ludovicianus),
diversity
quality.
to prefer
floridanus),
settlement,
landscape
discontinuous
Eastern
of conservation
Florida's
structure
within
10 years.
in 50 years,
conditions
of conservation
will have
(Lanius
biological
along
habitat
are known
(Podomys
extinction
of poor habitat
conditions
forestation
to European
vegetation
species
polyphemus),
aesopus),
reserve
because
suitable
Mouse
with
of suitable
concern
Continued
Tortoise
species all scrub
of conservation
conditions.
scrub
continue
is an indicator
frequent
is endangered
the next
fires
under
and
certain weather conditions. As a result of these changes, fuel structures developed that would most likely burn only under extreme conditions. Prescribed fire management has been conducted through the 1980's and 1990's, but has not reestablished habitat conditions that can sustain Florida Scrub-Jay populations. Smoke management, safety considerations, and meteorological conditions limited the range of conditions suitable for burning. Fires will not return most forested areas to scrub or marsh. Prescribed fires alone have not returned scrub to optimal habitat suitability. Florida Scrub-Jay populations continue to decline in scrub landscapes fragmented by forests or other areas of tall shrubs. Florida ScrubJays require a complex mosaic of openings among scrub oaks. Natural openings among scrub oaks do not remain long after fire in most areas that have been subject to fire suppression. Man-made edges provide suitable habitat for jays but do not adequately replace natural openings because they can be systematically searched by predators. Other management tools are suggested to improve scrub habitat quality. Several experimental restoration efforts have been conducted, and their results have been promising. These efforts have primarily involved the mechanical cutting of trees followed by prescribed fire. Restoration efforts need to be implemented on a larger scale. Many years of study have quantified relationships among fire, vegetation, habitat structure, habitat use, and reproductive success and survival of Florida Scrub-Jays. These findings indicate that the continued decline in habitat suitability can be reversed with intensive management. Reversing landscape and population trajectories resulting from practices of the past half century requires a long-term commitment. Habitats for population persistence must be recently burned (less than 15 years from the last fire) and must represent wide vistas where most Florida 10
Scrub-Jay territories are surrounded by other territories. Four major landscapes, designated as scrub reserve units (SRUs), should be restored and managed as optimal habitat. These SRUs are Shiloh, Happy Creek, Schwartz Road (south of the Vehicle Assembly Building), and the Southern Pinelands (south of the KSC/MINWR Industrial Area). Because Florida Scrub-Jays have limited dispersal and are vulnerable to predation when they are outside of optimal habitat, corridor regions are identified within the KSC/MINWR population SRUs and between CCAS. No large scrub areas on the Florida mainland can be connected to KSC/MINWR. The CCAS population has undergone a severe decline, but it represents a potential large population center. All corridors within the Cape Canaveral/Merritt Island ecosystem need habitat restoration. The scrub within the SRUs and corridors is approximately 7,000 ha. This could result in a population of 700 Florida Scrub-Jay territories if all habitat could be restored to optimal suitability. Recovery to this population size can only occur if reproductive success exceeds the mortality rate over many decades. Studies show that all conditions must be optimal for Florida Scrub-Jay reproductive success to exceed or equal mortality rates. Achieving optimal habitat conditions quickly by extensive restoration is unlikely. Therefore, it is important to manage for a large population size in order to attain low extinction risk. Questions remain about the exact habitat and landscape requirements essential for population persistence. Some habitat has become so degraded that it will be uneconomical or impossible to restore to optimal conditions. Much habitat that is not restored will have negative impacts on the surrounding scrub by limiting the dispersal abilities of jays and their ability to detect predators. Thus, restoration of the population to 700 territories is likely to be a lengthy process involving adaptive management practices. Restoration of fire frequencies need to be adapted to site-specific fire history, past soil disturbance, and the amount and distribution of accumulated underground biomass. Restoration efforts need to include frequent burning for 11
at least 10 years and the additional mechanical treatment of forests. It is important not to burn all scrub within a unit at once in order to provide cover, acorns, and nest sites for resident jays. Prescribed fires need to occur under narrow meteorological conditions, for smoke and safety reasons, so that multiple fires may be needed within some units to accomplish objectives. Generally, most burn units (BUs) within the core reserve need to have 20-40% of the area burned every one to three years depending on the extent of habitat degradation within the BUs. A less frequent fire management regime can probably be used once the initial intensive treatments have been completed. Mechanical tree cutting is needed for oaks that have grown too large and pines that have grown too dense. Careful logging of pines along man-made edges and other disturbed suitability.
The
mechanical
Intensive needed
used
as models
population
for finely
recovery.
Jay population range
quickly
of habitat
conditions
The greatest
additional
prescribed
burning
equipment
and personnel
team
is needed
supervise
burns
the KSC/MINWR
for at least
whose
leaders
whenever population
This
must
can
needed
and the Florida techniques
be
for Scrub-
and the
the frequency
be supplemented cutting
burns
and operations endangered
12
landscapes
persistence.
for the mechanical
will become
will be optimal
habitat
is to increase
plan and evaluate
weather
to achieve
the management
10 years.
needed
and monitoring
of vegetation
needed
in habitat
improvement.
experimental
for population
effort
slower
of the remaining
monitoring
essential
may yield
These
restoration
to establish
improvements
it will be difficult
in most areas. tuned
in rapid
techniques
because
Continued
is essential
of oaks
restoration
landscapes,
conditions
can result
cutting
and expedited
in several
habitat
areas
permit.
with the
of trees.
on a daily Without
with extinction.
of
A burning
basis such
and efforts,
Acknowledgments
This Operations J. Barkaszi,
study
was funded
Office
at KSC/MINWR.
M. Burgman,
Knott
III, C. Hall,
Stith,
H. Swain,
by NASA,
R. Hight, J. Thaxton,
R. Bowman, R. Hinkle, O. Tilley,
administered
We thank
B. Summerfield,
R. Farinetti, M. McCarthy, B. Toland,
13
by the Biomedical
S. Ferson, E. Menges,
R. Akcakaya, J. Fitzpatrick, M. O' Connell,
and G. Woolfenden.
M. W. B.
1.0
The breeding
Florida
bird,
endemic
(Woolfenden America's than
Scrub-Jay
of North
America's
habitation.
Stith
exceed
core
an area
Typically,
monogamous
meters
et al. 1995,
for males
parents
than
Breeders
the year
burned
in press).
Most
respectively.
one year,
"helping"
and care for subsequent
offspring
once
upland
et al. in that
probability
their
of
entire
lives
and Fitzpatrick
within 1984,
by permanently 1984,
are within
1991;
300 and 1000
usually
to detect
as
et al. 1991 ).
spend
Young
Space
populations
a high
Fitzpatrick
dispersals
and
(Fitzpatrick
is defended
and
due
is designated
(Woolfenden
scrub
like
Florida
for agriculture
range-wide
provide
to more
Scrub,
across
on Kennedy
(Fitzpatrick
(Woolfenden
and females,
for greater
the territory,
pairs
is imperiled
are contiguous
properly
is one of North
important
(KSC/MINWR)
populations
are territorial.
all periodically
breeding
Refuge
species
et al. 1994 a).
population
populations
throughout
Scrub-Jay
in an ecosystem
for the species
Such
threatened
and its destruction
Wildlife
is managed
Scrub-Jays
Florida
(Breininger
Scrub-Jay
Core
is a cooperative
listed
habitats,
regimes,
Florida
that is defended
Breininger
fire
pairs.
The
It lives
fire-maintained
et al. in press).
Florida
1991).
concern
populations
if the habitat
coerulescens)
is a federally
birds.
National
400 territorial
survival,
1991).
The
Island
one of the three press,
1984,
of natural
Center/Merritt
that
of conservation
to the disruption human
to Florida,
habitat-specific
100 species
many
(Aphelocoma
and Fitzpatrick most
Introduction
remain
and mob
(Woolfenden
with their
predators,
defend
and Fitzpatrick
1984).
Scrub islands
and along
Florida, 1991, Here
dominated most
of the Atlantic
but are now among Larson
scrub
1992, includes
natural
Bergen native
communities
Coastal
Ridge
the most endangered 1994, shrub
14
of eastern
communities
Cox et al. 1994, communities
on east coast
Swain
dominated
barrier
mainland (Snodgrass
et al.
et al. in preparation). by saw palmetto
and
mesic shrubs on poorly drained soils and dominated by scrub oaks on well drained soils (Schmalzer and Hinkle 1992 a, b). Natural fires burned frequently in these landscapes and maintained their habitat structure and species composition (Vogl 1973; Campbell and Christman 1982; Means and Campbell 1981; Mushinsky 1985; Abrahamson and Hartnett 1990; Myers 1990; Schmalzer and Hinkle 1992 a, b; Breininger and Smith 1992). All other species of conservation concern that depend on scrub (e.g., Gopher Tortoise, Eastern Indigo Snake, Florida Mouse) also require frequent fires (Speake et al. 1978; Layne 1990; Auffenberg and Franz 1982; et al. 1991 b, 1994 a, 1994 b; Ostertag and Menges 1994, Hawkes and Menges 1995). Many of these species are threatened with regional extirpation management only
large
occur
of the few remaining remaining
on federal
subregion
properties
include
1, Appendix
habitat
This
Service
and CNS quality
(Swain
(USFWS),
lands
and a declining
that extend
and Labisky Coast
and Space
significant
Florida
scrub
1991 ). The subregion
tracts
in the
and private
lands
considered
Federal
Air Station
(CCAS),
beyond
KSC/MINWR which
Administration Park
population
Scrub-Jay
and
Smaller
KSC/MINWR
and the National
also have
restoration
et al. in preparation).
emphasizes
Aeronautics
Park
Canaveral
(CNS)
document
the Atlantic
State
Cape
Seashore
of National
and Wildlife
County
(Noss
et al. in press).
Dickinson
KSC/MINWR,
National A).
jurisdiction
CCAS
on Jonathan
reserves
within
(Fitzpatrick
in Brevard
of Canaveral
of scrub
properties
occur
for acquisition
tracts
large
without
Service
(Figure
is under
(NASA),
U.S.
(NPS).
Other
potential,
population
and areas
but have
Fish
poor
(Percival
et al.
learned
at the
1995).
1.1
Optimal
Florida
Much
of what
Archbold central
Biological Florida.
Scrub-Jay
is known Station
Applied
Habitat
about
scrub
(Archbold),
and theoretical
ecology
located studies
15
has been
on the Lake have
been
Wales conducted
Ridge at
in
I
0
5
10
km
Figure
":'!'i:::.
1. Boundaries
National Wildlife Air Station.
of John
Refuge,
F. Kennedy
Canaveral
Space
National
16
Center,
Seashore,
including
Merritt
and Cape
Canaveral
Island
Archbold
for more
Scrub-Jay burned
habitat
at once
fire regime
similarities
in scrub
are also only
1.1.1
after
landscape
avoid
Fitzpatrick
tree
with 1984,
cover)
jays
that was unburned
for
water
table,
This
more
mainland
scrubs
(Schmalzer
a, 1995).
Although
there
Ridge
are
and KSC/MINWR,
and 10 years
of habitat
most
there
of KSC/MINWR of applied
has
studies
here.
where
Florida
(Woolfenden
1974,
1974,
et al. 1995).
Scrub-Jays
1984).
are common,
(Woolfenden
typically
hawks
vulnerable
and Sharp-shinned
al. in press).
pines
Breininger
by Florida
and Fitzpatrick
scattered
et al. 1995),
(McGowan
are especially
1984,
can be
Florida
Scrub-
although
Woolfenden
they and
et al. 1995).
avoid
woodland
10 ha in size within
preferred
(Woolfenden
Breininger
average
and Fitzpatrick
high pine densities
(Breininger
Scrub-Jays
cooperil]
for
the dynamics
typically
(Woolfenden
Scrub-Jays
spot and evade adult
territories
attributes
Florida
enough
than
to predict
is
but is not frequent
matrix
Wales
not all habitat 1991).
scrub
et al. 1991
for Florida
and Fitzpatrick
has a higher
of management
in landscapes
areas
Ridge
where
scrub
on the Lake
as low and open
occur
Woolfenden
management
Characteristics
habitat
described Jays
15 years
Scrub-Jay
undisturbed The
b; Breininger
ecology
years
KSC/MINWR
drained
Our ability
Landscape
Florida
poorly
optimal
8-20
Wales
KSC/MINWR
1992
distinctions.
begun
et al. 1991,
not to restore
and a more 1987,
every
for the Lake
20 years.
and Hinkle
At Archbold,
burning
(Fitzpatrick
at least
than
nutrients,
25 years.
includes
is suitable
KSC/MINWR, greater
than
Scrub-Jay Woolfenden
areas
because
(i.e.,
there
accipiters).
and Woolfenden to accipiters Hawk
near forests
[A. striatus])
mortality
results
and Fitzpatrick
17
than
they have
reduced
Accipiters
are predators
1989) (i.e.,
(greater
and evidence
Cooper's
Hawk
on KSC/MINWR mostly
from
1984).
Florida
65%
abilities
suggests
to
on that
[Accipiter (Breininger
et
predation Scrub-Jays
not
only do not use pine forests (Cox 1984) but avoid Blue Jays (Cyanocitta which
are competitors
1991).
Blue Jays
near forests
are common
but are rare
and Schmalzer
Nest
1990,
et al. 1992).
allows
in recently
Scrub-Jays
dominated
Vegetation
to monitor
for Florida
Scrub-Jays
may not be effective
found
the nest
(Lohrer
and Fitzpatrick predators
1980,
1984).
(Francis
et al. 1989).
(Masticophis
flagellum)
adult
Scrub-Jays
Florida
of recently terrestrial
The woodlands
burned
burned open
providing
and
Breininger
et al. 1980,
Terrestrial
predators
Indigo
Snakes)
1990,
(recently
burned)
scrub
refuge
once
and the activities.
1980,
(e.g.,
of foraging
Eastern
1989),
has
Woolfenden
Coachwhip
are important
the detection
Florida
the predator
the course
and Woolfenden
may also facilitate
(Schaub
Webber
may alter
Scrub-Jay's
scrub
in their
predators
mobbing
(McGowan
scrub
while
at deterring
and Eastern
cover)
1990,
the Florida
to be inconspicuous
However,
20% tree
1984,
1992).
by frequently
Patterson
Fitzpatrick
(Breininger
that characterizes
Scrub-Jays
than
influencing
a large area
opportunity
scrub
and Smith
factor
and
(greater
burned
is a primary
for landscapes
(Woolfenden
in woodlands
Breininger
predation
preference Schaub
and nest predators
cristata)
predators
on
and the openness
and avoidance
of
predators.
fragmentation
of scrub
and forests.
suppression,
Disturbances
and other
edges
of habitat
within
habitat
landscapes related
disruptions
fragments
fragments
(Breininger
et al. 1995).
tall shrubs,
no longer
of natural
unsuitable
results to human
for jays. influence
Landscapes,
fragmented
Florida
Scrub-Jays
18
Forests
have not only
the suitability
large
fire
made
many
replace of nearby
by woodlands, to scan
of
development,
fire patterns
but negatively
allow
in an increase
areas
forests,
scrub habitat and
for predators.
1.1.2
Focal
Habitat
Optimal 1984;
Patches
Florida
Woolfenden
Scrub-Jay
habitat
and Fitzpatrick
al. 1995;
Duncan
following
attributes:
1984,
et al. 1995 a) occurs
a) 10-30%
(Westcott 1991;
1970;
Breininger
as patches
of the area comprised
1992
(focal
of bare sand
Woolfenden
b; Breininger
habitat)
or sparse
1974;
with
Cox et
the
herbaceous
vegetation,
b) greater
than
( Quercus
spp.),
c) a shrub
height
d) less than
e) greater
Scrub-Jays
within
represents condition
100 m from
increasing
condition
a territory
the potential
Patches
photographs
remained
unburned
Most patches (Serenoa
focal time
Habitat
potential
Florida within
Lyonia
of having
oaks
enough
by defending
patches 1984).
and Fitzpatrick
Oak scrub in optimal
Breininger
depending
on the time
since
little oak scrub
on Merritt
Island
(see
Scrub-Jay
1984,
large
in optimal
but not all of it is necessarily
that very
a matrix
fires
and Fitzpatrick
vary in quality
lucida)
of scrub
and
to frequent
(Woolfenden
Matrix
repens,
adapted
habitat,
suggest
comprised
a forest.
for long periods
of oak scrub
cover,
(Woolfenden
of oak scrub
Historical
1.1.3.
have
layer
cm,
the probability
at the same
1995).
of 120-170
15% pine canopy
than
Florida territories
50% of the shrub
Section
habitat
of little-used
and swale
19
et al. fire.
2.3).
on KSC/MINWR habitat
marshes
occurs
as
of palmetto-lyonia
(Breininger
et al. 1995).
These native matrix habitats provide prey for Florida Scrub-Jays and habitat for other species of conservation concern (Moler and Franz 1987, Breininger et al. 1994 a, b). The flammability of native matrix habitats is important for spreading fires into oak scrub that often burns poorly (Webber 1935). Saw palmetto, gallberry holly and marshes, oaks
(llex glabra), are more
(Abrahamson
Schmalzer
b, Abrahamson
Fish Crows
(Corvus
15 years),
native
and Smith
1992).
matrix
Past
disrupt
Logging, KSC/MINWR (Appendix the land
Scrub-Jays,
prior
ownership
MINWR
and CNS
prescribed
occurred
Fire
USFWS
(Adrian
1992).
fuel
Ioadings
to manage suppressing
wildfires.
another
primary
Farinetti
1995).
Ioadings
has been Initially, to reduce Habitat
objective
habitats
in most
Myers
with
scrub
1990,
habitat
Scrub-Jays,
regularly
such as
burned
and Fitzpatrick
1991,
into woodlands
the habitat
(every
suitability
3-
Breininger
and forests
and forests
when
are not
of nearby
scrub,
et al. 1994).
and agriculture and USFWS were
suppression
and fuel
fire program
than
Overview
to NASA
The
rapidly
1990,
woodlands
(Schmalzer
land clearing,
in the 1960s.
few wildfires
These
more
of Florida
develop
decrease
Management
ditching,
B).
often
of fire regimes.
fire patterns
Habitat
predators
(Woolfenden
habitats
fuel
matrix
that are rare
habitats
Matrix
for Florida
and further
adds
saw palmetto-lyonia
1992 a).
of native
ossifragus),
is a disruption
suitable
areas
dominate
and Hartnett
and Hinkle
or replacement
and industrial
which
and accumulate
et al. 1991 ; Schmalzer
fragments
1.2
flammable
1984
Degradation
there
and grasses,
objective
the hazards
and
and
1990s
of prescribed
and costs
for a variety
prescribed
2O
NASA
to dangerous
in the 1980s
the primary
of the current
after
in the 1960s
accumulated
conducted
natural
habitat
on
and NPS jurisdiction
established
occurred
management,
altered
associated of species,
fire program
purchased 1970s
when
levels.
A
by the burning
was
with has become
(Adrian
and
2.0
Detailed
Florida
data
are available
from
several
(Figure
1995,
sites in press,
spatial from dating
from
xeric
the existing
Scrub-Jay
long-term
2.1
than
study
Scrub-Jays
et al. 1994; data).
changes
from
Breininger
Remote
in habitat
on sequences
based
population
Much
et al.
sensing
and
and landscapes
of aerial
photography
that based
on the acreage
of 700-800
of the scrub
especially
population
has become,
of natural
north
families
potential.
size on KSC/MINWR
1989,
or is in transition
Canal
to,
Consequently,
(Section
Documented have
could
(Breininger
fire regimes.
of Haulover
on habitat
of scrub,
3.5),
is
declines
occurred
in
in several
sites.
Risk Assessments
Population reproductive for Florida detail
to quantify
of the disruption
population,
smaller
Florida
because
Florida
densities
2.3).
Scrub-Jay a).
Smith
Status
and territory
banded
unpublished
on KSC/MINWR,
et. al. 1991
hammock
much
(Section
habitat
for a Florida
Breininger
Schaub
that are identifiable
the 1940s
survival,
of color
et al. 1993;
used
and Habitat
success,
of study
2) (Larson
are being
Potential provide
3-8 years
features
Population
on reproductive
in preparation;
analyses those
Scrub-Jay
risk
success
models
and survival
Scrub-Jays
in Appendix
incorporates and presence
from
of helpers.
sets that had insufficient breeders. breeders
This
second
(breeders
with
future
in Figure
Breininger
independent Another sample ("simple") helpers
trends
(Burgman
is summarized
D (and see
stages
predict
model
model
et al. 1993).
The
through
to distinguish distinguished
21
"primary"
without
data
model
The model
breeder
experience,
for KSC/MINWR
novice
from
data
experienced
only two classes helpers).
on
in greater
ms.).
adult,
was developed
and breeders
using
3 and is presented
et al. unpublished young
sizes
in populations
of
"!
0 Figure
2. Florida
Seashore, Shuttle
3
6 Scrub-Jay
HC-Happy Launch
...........
Creek,
study areas. SLF- Shuttle
Complexes.
22
CNS-Canaveral Landing
Facility,
National LC39-
Figure 3. Florida Scrub-Jay features of Florida Scrub-Jay
population risk model. The model incorporates sociobiology. The model implements Monte Carlo
simulations
and variances
using
of six stages fledglings based
Scrub-Jay.
and two helper
on habitat
breeders novice
the means
the Florida
stages;
acreage;
after one year breeders
breeder
mortality;
of breeding;
5) older
first year
helpers;
breeding
vacancies
2) there
3) novice
is dependent
of reproductive
Model
is a ceiling
breeders
that
helpers
are unfilled
have
on the number become
chance
that survive
can become
by helpers;
7) the number
include
of breeders experienced
of nonbreeders
of breeding
the first
and survival
1) nonbreeders
survive
4) the number
on the number
6) fledglings
success
assumptions:
becoming
vacancies
attributed
to breed,
followed
first
breeders
year
of nonbreeders
to
by if is
dependent on the survival of nonbreeders that have
of nonbreeders from the previous years, the number no chance to breed because there area no vacancies,
the survival
and the ceiling
of fledglings,
habitat.
The dotted
survival
and transitions
lines
represent from
on the total
reproduction
one stage
number
of helpers
and the solid
lines
represent
to another.
f
'
\
/
f
Experienced breeders
/ /
/
l
_
xperienced breeders
helpers
/ without
-1 with
helpers__
/,'
_
Novice breeders
Older helpers
\ First Fledglings
helpers
23
I
based
_,'
on
Both models perform fecundity ceilings,
are sampled attributed
breeders
2.2
from
to strict
and helpers
Population
model
was
data).
Ten
years
and Fitzpatrick
KSC/MINWR
data.
used
The in Figure Fitzpatrick burned matched without
to predict
population
1984,
primary
habitat
showed
mortality
during
mortality
of adults
and Fitzpatrick
Consequently,
per year
(Woolfenden
at Archbold
populations
at
The
simple
Archbold
model
habitat
trends
(Woolfenden
Reproductive in optimal 1984).
Archbold
A severe
the epidemic estimate
and Fitzpatrick
1991,
and
periodically
success
and resulted
survived
was
is presented
in the optimal,
at Archbold
24
Smith
to simulate
4A.
a reasonable
et al. 1993;
for
and Fitzpatrick
few juveniles
on data
comparison
rate (;_)=1.00)
of study
based
a standard
population
Figure
of
ms.; R. Schaub
collected
Populations
decline
one of 20 years
is 0.05
used
on optimal
growth
and helpers;
data
based
a slight
number
of habitat.
(Larson
unpublished
and CNS.
et al. 1991).
on the total
trajectories
complexes.
to observed
Population
Risks
at Shiloh
(Woolfenden
1984).
was
and
data.
on the amount
provide
and Titan
trajectory
(population
catastrophes
1991)
model
Creek,
Fitzpatrick
are placed
population
in press,
mortality
empirical
sites on KSC/MINWR
4A and is very similar 1991,
where
upon
based
of demographic
populations
occurred
probability
The
Tel 4, Happy
to simulate
used
et al. 1995,
(Woolfenden
Archbold,
behavior,
and Extinction
five study
Breininger
unpublished
territorial
simulations based
and are ultimately
at Archbold,
et al. 1994;
Carlo
distributions
Trajectories
The risk collected
Monte
exactly habitat
epidemic in high (Woolfenden
of epidemic Fitzpatrick
et al.
Figure 4. Population trajectories using reproductive success and survival data from A) optimal and B) unburned Archbold habitat. Mean and standard deviations of 1000 simulations represented. Assumes that epidemics occur with a yearly probability of 0.05. Other catastrophic events are excluded.
A. Optimal 8OO 7OO N_ c
6OO o-
5OO 4OO 3OO
0 O..1_
2OO 100 0 0
10
20
30
40
30
40
50
Years
800 7OO .N .,.-
6OO
c o
5OO
{3. c_
4OO 0 _I_. Q v
3OO 2OO 100 0 0
10
20 Years
25
50
1991).
A slight
decrease
or catastrophes
in population
are incorporated
It is not appropriate decline
based
assessments population
growth
to predict
for periods
changes
(;_ = 1.00),
longer
than
growth
analyses
rates
or lower
optimal
was maintained
otherwise
noted),
acknowledging
The for 25-40
The
years
decline
at Archbold
and extinction
throughout
Brevard
(Fitzpatrick
et al. 1991).
2.2.1
in an exactly
assessments data.
rates
or decrease.
result
populations
from
Extensive
throughout
ms.).
typically
Very
slight
1.00
result
need
in
in vital
prediction
for
The epidemic
the remaining
that the frequency
stable
increase
population
et al. unpublished
risk
sensitivity
that a few percent in a stable
will
analyses
of epidemics
(unless
may be higher
(Woolfenden
County
using
of Florida (Swain
associated
with habitat
and Fitzpatrick
vital rates
within
Scrub-Jays
unburned
1991 ) was also such
habitat
in unburned
et al. in preparation)
(Figure
habitat
4B).
occurs
and statewide
Tel 4
The
Tel 4 site (Figure
fire suppression forests
developed
burned
five times
keeping
risk
et al. 1993).
Few population
empirical
and extirpation
with the simulations
decline
that results
epidemics
modeled.
population
consistent
Scrub-Jay
and survival)
showed
when
(Burgman
trajectory.
but population
(Breininger
of 0.05
than
data
success
frequency
or lower
in the above
frequency
habitat
model
Florida
the available
model
epidemic
Archbold
that
that increase
of the population
is common
a population
empirical
in vital (reproductive
population
rates
decline
long term rate
into
to conclude
on the slight have
trajectories
shrubs
period
and did not lose
in several since from
2) was burned
1979.
exceeding
areas
once
openings used
Prescribed optimal
by at least
26
among
scrub
for agriculture.
burns height
one wildfire
at Tel 4 were and maintaining
during
oaks, The
the
although
study
effective openings
area at among
scrub oaks in most areas (Duncan et al. 1995 b, Duncan et al. in press). The Tel 4 study site was adjacent to private lands where scrub has undergone habitat destruction and fire exclusion. The population trajectory, using the primary model, for Tel 4 suggested a 25% decline within 10 years (Figure 5A). A decrease in the number of territories or birds has not been documented (Breininger et al. in press). The decline in the Tel 4 trajectory was sensitive to model assumptions in contrast with other trajectories below. The Tel 4 study site has higher habitat suitability for Florida Scrub-Jays than most areas on KSC/MINWR because there are few tall shrubs and an abundance of openings. Population dynamics within subpopulations are dependent on demography in nearby subpopulations and the dispersal of individuals from other subpopulations. Population declines are not always obvious in subpopulations where mortality exceeds reproductive success, if these populations have higher habitat suitability than their surroundings (e.g., Pulliam 1988, Howe et al. 1991, Pulliam et al. 1992, Dunning et al. 1992). Therefore, extinction risk is not always realized until extinction is inevitable (Howe et al. 1991, Pulliam and Danielson 1991). High immigration of Florida Scrub-Jays resulted in abnormally high Florida Scrub-Jay densities that may have lowered survival (see Watkinson and Sutherland 1995). Most immigrants appeared to be from adjacent private property where habitat has been destroyed for housing or has remained unburned for long periods (Breininger et al. in press). The data suggested that a density dependence relationship (at least at very high jay densities) may influence survival at Tel 4 but more data are needed to confirm this relationship.
27
Figure 5. Population trajectories using reproductive success and survival data from A) Tel 4 and B) Happy Creek. Mean and standard deviations of 1000 simulations represented. Assumes that epidemics occur with a yearly probability of 0.05. Other catastrophic events are excluded.
800
A. Tel 4
7O0 N "_ E
o
._ (_ {3L
o)
600 500
E
o
_5
400
'--
300
a_ _
200 100 0
• --
0
10
20
30
40
50
40
50
Years
B.
8OO
Happy
Creek
700 ,_ ._
600
500
400 300 n°_'-_
200 100 0 0
10
20
30 Years
28
Some evidence also suggested a negative influence of helper densities on breeder survival at Archbold (Woolfenden and Fitzpatrick 1984). Density dependence of survival rates could have been incorporated into the model. But logistic and similar density dependence formulations should not be used without strong evidence for such forms of density dependence because they can seriously underestimate extinction risk (Ginzburg et al. 1990). Sensitivity analyses of these density dependence models (i.e., Beverton-Holt, logistic or Ricker equations) confirmed that extinction risk was underestimated for habitat conditions (and associated vital rates) where failed
long term outside
improvements
stability KSC/MINWR
Immigration
attributed success
Tel 4 that could et al. 1995
a).
edges
adjacent
Happy
population site was
populations
attributed
readily
such
Island
these
by tree cutting.
have
Restoration
by Florida
resulted is needed
Scrub-Jays
in
suitability
et al. 1995;
and 1950's
et al.
Variation
in habitat
(Breininger
(Swain
persistence.
is temporary.
to variations
for
population
20 pairs
for population
areas
in the 1940's
are needed
Scrub-Jay
is less than
by restoration
competition
areas
Florida
little chance
leaving
has been
or else
sites,
at Duncan in many in
will continue
for
as Tel 4.
Creek
Happy centers
subjected
sequences
to jays
have
that can be restored
landscapes
The
jays
be altered
The
on Merritt
Soil disturbances
the few quality
Creek,
property
and these
demographic
at Tel 4 and in surrounding
of the Tel 4 population.
in preparation),
2.2.2
Scrub-Jay
to persist.
Habitat
forest
Florida
Creek
(Figure
on KSC/MINWR to 20 years
(1943-1979)
and the
area
landscape
2) is one of the largest (Breininger
et al. 1991
of fire suppression
showed became
that natural increasingly
29
before
openings forested.
potential a). The
Happy
Creek
1979.
Photographic
disappeared
from
The
study
area
Happy burned
five times since 1979. Prescribed burns at Happy Creek have not effectively reduced shrub height in many areas and natural openings have not returned (Schmalzer and Hinkle 1992 a). The population trajectory for Happy Creek suggested a decline by 50% within 10 years (Figure 5B). Sensitivity analyses indicated that minor changes in demographic data or epidemic frequency have little influence on the trajectory. Actual declines in mean family sizes and territory densities have been observed (Breininger et al. in press). Conspicuously, poor reproductive success represents one causative factor in the population decline (Breininger et al. in press). The loss of natural openings among scrub oaks, increase of tall shrubs, and the replacement of marsh and scrub by forest has been characteristic of this landscape for nearly 20 years. The population decline in the Happy Creek area has probably been occurring for decades. Although most Happy Creek scrub is of low to moderate quality, it is in better condition than many other areas on KSC/MINWR. Therefore, a decline at Happy Creek might have been masked by immigration until there were no more immigrants, if color banding studies had not been conducted. 2.2.3
Titan
Study
Complex
areas
surrounding
a history
of fire suppression
occurred
but they were
areas. Jays
There (Larson
natural became
et al. 1993). among
a woodland
for greater
launch
(Figure
2) have
had
A few unplanned
fires
rapidly
and these
fires
large
little or no evidence
for launch
impacts
Photographic scrub
than
complexes
35 years.
extinguished
has been
openings
the Titan
sequences
oaks disappeared
or forest.
30
did not burn
(1943-1989) and most
to Florida showed
of the landscape
Scrubthat
The population trajectory for Titan launch complexes suggested a population decline by of 50% within 10 years (Figure 6A). Sensitivity analyses indicated that minor changes in demographic data have little influence on the trajectory. Actual declines in Florida Scrub-Jay population have occurred (Larson et al. 1993, D. Oddy, unpublished data). Declines have probably occurred for longer periods than have occurred at Tel 4 and Happy Creek. The Titan launch complexes occur along a narrow stretch of coastal habitats that connect KSC/MINWR and CCAS. The population on CCAS is more vulnerable to extinction due to a long history of fire suppression. Ongoing studies indicate that the CCAS population is only a portion of its potential and that reproductive success and breeder survival on CCAS is especially poor (Percival et al. 1995). 2.2.4
Shiloh
This for longer Much
Haulover
landscape periods
scrub
years.
and
in these
sequences
within
potential
3.5).
10 years have
(Figure
Declines
have
6B).
Actual
Florida
This
agricultural
disturbance practices.
for greater
areas.
than
35
Photographic
disappeared
suggested
unpublished
Scrub-Jay
occurred
and most
of
decline
by
years.
31
data).
is less than periods
area of scrub
has been
largely
a population
in Florida
population
for longer
is a large
area
openings
declines
a) but the population
There
large
soils
or forest.
and Haulover
probably
Creek.
CNS jurisdiction.
that natural
(R. Schaub
a large
et al. 1991
Tel 4 and Happy under
for Shiloh
to greater
of fire suppression
but they did not burn
a woodland
occurred
subject
due to earlier
had a history
showed
became
to support
(Breininger
areas
2) had been landscapes
occurred
The trajectory
population
most
(1943-1979)
the landscape
25%
(Figure
than
A few fires
Canal
Scrub-Jay The
Shiloh
area
has
on KSC/MINWR 1/2 its potential than north
unburned
have
(Section
occurred
at
of KSC/MINWR for greater
than
35
Figure 6. Population trajectories using reproductive success and survival data from A) Titan launch Canaveral National
complexes, Seashore.
simulations represented. of 0.05. Other catastrophic ._. N
Assumes events
that epidemics are excluded.
occur
with
800
.h
"_ __ E O
B) Shiloh and Haulover areas, Mean and standard deviations
600
O)
_5
400
h_
200
D
o
13.-.....
0 0
"_" N
B. Shiloh
800
30
and Haulover
40
Canal
50
Area
600
_)
_5 a.
20 Years
.__
,-- _ 0
10
400
G)
o _ 13_.-.
200 0 0
•
•
•
•
•
10
20
30
40
50
Years
800
Canaveral
National
Seashore
N E O
¢_" {:t)
60O 4OO
Q- Q) O l._ I::L -_
200 0 0
10
20
30 Years
32
40
50
and C) of 1000 a yearly
probability
2.2.5
Canaveral
This
National
landscape
and habitat
Florida
fragments.
Much
than
USFWS
The
Florida
are also
in these Many
fires
trajectory
6C).
Scrub-Jay
construction
occurred
to road
mortality
burned
of this study
suggested
a population
have
indicated
(Smith
(Smith
in these
large
et
habitat for
areas
under
area.
decline
by 25% within
that minor
on the trajectory.
occurred
disturbance
of fire suppression
but they
analyses
soils
of NPS facilities
had a history
little influence
population
to greater
and south
Sensitivity
data have
subject
subject
areas
to the north
population
demographic
due to recent
scrub
35 years.
(Figure
2) had been
Scrub-Jays
jurisdiction
10 years
(Figure
fragmentation
al. 1994).
greater
Seashore
changes
Actual
declines
et al. 1994,
in in
unpublished
data).
2.2.6
Estimated
Recent Jays
Population
studies
have
on all nonfederal
levels
(Fitzpatrick
the KSC/MINWR
Declines
identified
properties
at local
et al. in press). population
at such
to document
changes
monitoring
has focused
on detailed,
of the KSC/MINWR
indicate
that
occupied
Florida
Breininger
pers.
The vital KSC/MINWR for KSC/MINWR.
highly
never
Scrub-Jay
been
made
and the available size (Appendix
reliable
Numerous,
no longer
Florida
et al. in preparation)
have
accuracy,
landscape.
Florida
(Swain
in population
Scrub-Jays
in 1978 when
all of the remaining
Attempts
insufficient
portion
nearly
data
occupy
many
studies
began
and state to estimate
estimates E).
collection
qualitative
Scrub-
are
Ecological for only
a
observations
areas
that were
at KSC/MINWR
(D.
obs.)
rates from
population
long term study to estimate
The same
vital
different
rates
sites
can be applied
probabilities
and model
33
to the
of population
that were
used
decline
for the above
population trajectories were applied to estimate the probabilities of different rates of decline at the end of 10 years, a procedure referred to as terminal percent decline (Ferson 1991). Although the actual decline in the KSC/MINWR population is impossible to determine, one can use the results of such analyses to estimate the probabilities and magnitudes of the decline. Terminal
percent
decline
that all KSC/MINWR
study
10 years
The
(Figure
optimal
7).
habitat
in ten years historical
mapping
Schmalzer
et al. 1994)
population (Section
than
Hinkle
has declined 3.5).
KSC/MINWR
It is not possible
may only
be approximately
Extinction
Extinction probability
decline
The
Creek
1980,
been
longer
landscapes
probably
as an assumption
10 years. potential
decline
in decline
1981,
1991 a;
responsible
50% from its habitat
in
Ongoing
Breininger
than
20%
decline
areas.
et al. 1988,
the actual
than
of a 40%
and Titan
conditions
than
70% probability
population probability
(Stout
occurring
than
of greater
that the habitat
400 breeding
for the The at Shiloh
for the entire
had different
suggests
the current
extinction
risk which
rates
of
population
pairs.
Risk
risk
is often
that a population
during
represent
a 40%
collection
to estimate
different
Using
once
have
population;
20%.
1992 a, b; Breininger
by more
decline.
2.2.7
less than
suggest
decline
of at least a 20%
data
1987,
a greater
a decline
70% for Happy
and habitat
and
Scrub-Jay
was
indicated
experienced
probability
greater
Schmalzer
Florida
areas
at Archbold
was
results
a specified
the probability
presented
as quasi
will fall below
period
a threshold
of time (Ginzburg
of falling
below
et al. 1992).
a threshold
34
population
population
is the
size at least Here,
risk curves
size at least
Figure 7. Comparative probabilities of population declines. The percent decline is the percent of the population that declined at the end of a 10 year period. The curves resulted from 1000 simulations beginning with a population size of 700 breeding pairs. Assumes that epidemics occur with a yearly probability
of 0.05.
Other
catastrophic
events
are excluded.
1.00 •--e---
Optimal
_x---.Tel 0.80
•-_-
(Archbold)
4 Happy
Creek
_Titan o
0.60 O
.13 ..(3
0.40
o
0.20
0.00 0
20 Percent
40 decline
35
80
60 after
10 year
period
100
once during a 50 year period, a realistic management time frame. Demography from three study areas was used in three simulations to provide several estimates of risk for the entire KSC/MINWR population. The quasi extinction probabilities for the Happy Creek and Titan areas (Figure 8) suggest that the KSC/MINWR population has a greater than a 95% probability of declining from 400 to 50 breeding pairs below from
10 pairs other
1991).
and Titan
2.3
2.3.1
in optimal
populations
The
period.
appear
to almost
(Fitzpatrick below
et al. 1991, 10 pairs
Florida
Scrub-Jay
invariably
Woolfenden
within
50 years
populations
go extinct
if isolated
and Fitzpatrick is 50% for Happy
Creek
areas.
Landscape
Change
Replacement
KSC/MINWR
of Scrub
and CCAS
now urban miles
south
urban
areas.
population
1992).
Today,
populations
within
area
the only
on the mainland
areas
been
the mainland
on Merritt
mainland
viability.
36
habitat
south
barrier
of CCAS
was contiguous
at Oak quality There
connection, conservation
are
for
is in agriculture
of KSC/MINWR
and of poor
for scrub
areas
once
occurs
on
on the outer
of this habitat
near the KSC/MINWR
due to low population
Most
Island
et al. in preparation).
recommended
habitat
contiguous
connection
fragmented
(Swain
Scrub-Jay
Inlet.
Now most
Florida
Suitability
Areas
was once
potential
to the
Scrub-Jays have
Habitat
is extremely
pine densities
Urban
as Sebastian
of KSC/MINWR.
Scrub-Jay that
with
in Habitat
shows that Florida
as far south
(Larson
many
and Declines
photography
to at least
and high
a 50 year
habitat
risk of falling
Historical
island
within
or
Florida
Hill but the habitat due to infrequent
fire
are few Florida and little to no on that area
of
Figure 8. Comparative extinction risk estimates. The risk curves represent the probability of falling below different threshold population sizes any time during a 50 year period. These threshold populations range from zero (extinction) to 400 breeding pairs, the beginning population size. Curves represent 1000 simulations and assume enough habitat to support a population of 400 breeding pairs. Assumes that epidemics occur with a yearly probability of 0.05. Other catastrophic events are excluded.
N
_
1.00
c" 0
13.
o 0..
0.80
"0 0
c-
0.60
0
"Q
Optimal 0.40
C
--x--
Tel 4
. ,L.
Happy
(Archbold)
Creek
Titan O
=
0.20
.13 O
0.00 0
50
100 Threshold
150 population
37
200
250
size (breeding
300 pairs)
350
4OO
2.3.2
Increased
Forestation
Pine densities year
period
fire
the landscape,
with severe
soils
been
areas
willow
(Salix
marshes
where
there
1985).
no longer
2.3.3
Loss
suppression returned 1981;
Much
prior
and do not persist
around
often scrub
Among
pines
burn for days, on KSC/MINWR
itself
areas
1990).
or where
especially
wax myrtle rubrum),
the soils
invaded
(Schmalzer
influences
marsh
(Myrica
have
in hydrology
by fragmenting
in areas
so that
and Schmalzer
marshes
Scrub
during
to 1978.
long after
and Hinkle
in many
fragments
flammable
17 years
surrounding
a previously
vegetation
open
so that
areas.
disappeared
that occurred
are abundant Snags
Openings
openings
Schmalzer
replaces
into surrounding
of Natural
Natural
and pine flatwoods,
a 20
fragmentation
(Acer
of swale
after
discontinuities
of fire or alterations
invasion
Even
not reestablish
(Breininger habitat
size during
to increase
in fuels
and red maple
is exclusion
vegetation
carry
does
Hardwoods,
caroliniana),
to 1978.
continues
often
within
disturbed.
scrub
Woody
fires
occur
tree
and habitat
oak forests
The woody
particularly
landscape.
palmetto
become
mechanically
and Hinkle
cover
and this results
and forests
cerifera),
habitats,
Saw
disturbance,
Pine woodlands have
forest
reached
prior
due to soil disturbance
et al. 1994).
disturbed
that occurred
management,
(Schmalzer
many
and scrub oaks
of fire suppression
of prescribed within
increased
1987,
Oaks
the 20 year
Natural
fires,
openings
except
sometimes
of fire
in scrub
in some
1992 a; Schmalzer
and snags
period
pinelands
et al. 1994).
on KSC/MINWR
(Breininger
weeks
creating
has always
after fires,
lacked
pines
have
not
(Breininger Openings 1992).
openings.
but historically
had many
openings.
Natural fire patterns
fire pattern achieved
and frequency
by management
within
the landscape
techniques.
Most
38
differed
natural
fires
from
the
occurred
during the growing season, and vegetation is adapted to growing season fires (Robbins and Myers 1992). Many prescribed fires have occurred in winter may explain oak cover
why natural as effectively
Furthermore, Different holly,
types
patches
burned
into wide
flammability openings
among
burn
Fire
across
large
fire to provide
scrub
Accounts
of scrub
of historic
on KSC/MINWR results
openings Scrub
(a major
oaks food
more
the fires often photography especially
need
without
having
that fire
stopped
due to low
cover
frequent
the edges
of saw
Ioadings
making
excessive
fires
to be at a sufficient
source),
than
indicate
shows
fuel
gallberry
frequently
along
in continuous
in oak scrub
palmetto,
fire patterns
oaks where aerial
and summer.
The
burned
do not reduce
et al. 1995).
winter
flammability.
probably
Historical
oaks
for long
(Breininger
located
Historic
The
along
edges
it that
age from the last
from predators,
and nest
Tel 4, Happy
sites
Scrub-Jay
they
used
be "mortality (Yosef
1990).
Florida
et al. 1990,
that can These
Scrub-Jays Fitzpatrick
by Florida
traps"
are et al. 1991 ).
Scrub-Jays
because
they can
be
1994).
Change
Creek
landuse/landcover because
where
(Dreschel
could
in openings
and Schmalzer
roadsides
by predators
Landscape
result
may be extensively
edges
searched
(Breininger
vehicles
1981 ), these
systematically
soil disturbances
periods
by motor
man-made
long-term
different
oak scrub
mechanical
killed
Although
selected
have
suppression
acorns
are often
frequently
historical
during
fires
Scrub-Jays.
openings
2.3.4
differ
areas.
Extensive, degrade
of fuels
1935).
to reestablish
for Florida
patterns
patches
scrub
palmetto-lyonia difficult
(Glitzenstein
oak.
(Webber
Winter
fires
within
of scrub
not returned.
season
of vegetation matrix
have
as growing
the moisture
and grass
wide
openings
which
span
study
and Shiloh
analysis much sites,
study
areas
on KSC/MINWR.
of the geographic
and represent
39
a wide
were
selected
These range range
areas
for were
of KSC/MINWR, of historical
are
landuse on KSC/MINWR. Aerial photographs from 1943, 1951, 1958, 1969, 1979, and 1989 were used to map a time series of landuse/landcover changes. Landuse/landcover categories were mapped and digitized into ARC/INFO. Coverages were registered, overlaid, and acreage's of landcover types were determined. These results will be discussed sections sites
for the Tel 4 and Happy
is currently
2.3.4.1
underway
Study
sites.
and is not presented
in the following
Work
on the Shiloh
study
here.
Tel 4
Since
the 1940's
and an increase Forest
cover
and then
landuse present.
and
(Figure
10).
in the scrub a wildfire
began
burned
management prescribed but have
until
of open area
to 1.6%
to 30.7%
in 1969
scrub
(Figure
9).
in 1969,
was at its maximum
large facilities
grazing habitat
in 1943,
and
the land
In 1977 during
the extent
in the scrub
before
4O
have
(Figure
were
range 1960's
of fire suppression, prescribed
fire
the implementation slowly
in the form
also
and the openings
the fire suppression
of soil disturbance
in the Tel 4 area
1970's,
After
with
in the early
into effect,
In the late
Other
herbaceous
open
this period
on KSC/MINWR openings
areas
by encouraging
went
ranching.
of crop farming
remained
purchased
the Tel 4 area.
1943 was
amount
fire suppression
management,
the ranch
it decreased
The
NASA
to disappear. through
were
it increased
scrub
and a limited
cover.
this point,
not yet reached
There
area;
in the Tel 4 area during
was implemented fire
in the Tel 4 study
Open
fire to improve
woody
continuing After
area;
as citrus
used
reducing
management
of the study in 1989.
landuse
such
Ranchers
growth
cover
in the amount
in 1989.
dominant
practices
1.3%
of the study
to 7.7%
a decrease
of forest
to 21.8%
10.4%
The
has been
in the amount
decreased
increased
there
in 1943 was
representing
support
Creek
and presented
began
of to return
period. of clearings
11 ). These
cleared
to areas
Figure 9. Historical landscape trends mapped using aerial
photographs
for Tel
4.
- o - Forest Open
2OO
scrub
--..n---
Closed
-
Marsh
•-
scrub
2.
150
100 iii
•
O-
•
.
I
m
m
,,0
0
50
-
0 1943
I
! 1951
1958
1969 Year
41
1979
1989
m OpenScrub 1943 m open Scrub 1969 m OpenScrub 1989 m open Scrub 1943& 1969 m OpenScrub 1943& 1989 [-Q OpenScrub 1969& 1989 m OpenScrub 1943& 1969& 1989
Uete_
Figure 10, The dynamics of open scrub in the Tel 4 study site on KennedySpace Center.
42
Cleared 1943-1989 Cleared-forested1969 Cleared-forested1989 Cleared-forested1969& 1989
Metem
Figure 11. Forest establishment on previously cleared areas in the Tel 4 study site on Kennedy Space Center, Redareas were cleared between 1943and 1989but were not forested in 1989. Green areas were cleared between1943and 1958and were forested in 1969.Blue areas were cleared between1943and 1979and were forested in 1989.Yellowareas were cleared between 1943and 1958and were forested in 1969and 1989,
43
were
abandoned
land.
Slash
areas. pines
pine (Pinus
With
rapidly
management
across
areas
it burned
area
during
restored
Tel 4 habitat
areas,
Prescribed
fire
by slash
cover.
Logging
restore
these
In 1943, increased
cleared understory, fire
but is unlikely
to
mechanical
other
under
period,
a native
many
areas
understory
Scrub-Jay
the
Fire
and thinning
the overstory.
cleared
area clearly
is able to carry
and recolonized
into the tall pine
pines
is required
which
reduced
understory.
(killing)
on scrub
in the scrub
burning
fire has also
not extend
in thinning treatment
prescribed
that were
does
on KSC/MINWR
and openings
As a result,
the canopy
practices
areas
to reduce
in addition
shows
forest
to fire to
the implications
with
a pine
inhabits
this
overstory dynamic
of
and the habitat
type.
Creek
Creek
gained
forest
cover and
of the Happy
Creek
study
to a maximum
of the Happy
the
Prescribed
additional
Prescribed
with
The Tel 4 study
for the Florida
5.2%
12).
of pine forests
many
lost.
areas
and mechanical
Happy
from
are ineffective
areas.
Happy
of 2.7%
over
land management
2.3.4.2
(Figure
type without
to optimal.
A flammable
so that fires
implications
differs
penetrating
canopy
different
purchased
and the lack of a flammable
native
has not restored
pines.
NASA
the abandoned
the Tel 4 landscape
not completely
cover
into these
in effect
after
vegetated
the fire suppression
were
of forest
densely
the rate of spread
oak vegetation
amount
abandonment
et al. in press).
The Tel 4 study
much
total
back to their
(Duncan
because
elliottil)
has reduced
these
treatment
until
fire suppression
spread
return
gradually
Creek
in 1969
of 18.2%
study site,
and increased
site was forest
in 1989.
increased slightly
lost openings
Open to 14.0%
to 3.3%
44
scrub
cover. in 1943
in 1951,
in 1989.
in scrub (Figure Forest
cover
comprised
decreased
13).
7.7%
to a low
Forest 1943 Forest 1969 m Forest 1989 m Forest 1948& 1969 D
Forest 1969& 1989
m Forest 1943& 1969& 1989
L Neters
Figure 12. The dynamics of forest in the Tel 4 study site on KennedySpace Center,
45
Figure Happy
13.
Historical
landscape
trends
mapped
using
aerial
photographs
for
Creek.
- o - Forest
Open
Scrub
Closed
" •"
Scrub
Marsh
400
300
tt_
200
,,0
100
.....
O'"
.....
_.:.2 " --
&
1958
1969
&
I
0 1943
1951
Year
46
1979
1989
Landuse less uniform intensely fields
practices
than
at Tel 4.
managed
(Duncan
extensive 1958.
have
The Happy difference
xeric
than
few pine differently needles
trees.
openings
openings
above monthly
mesic
were
many
were
scrub
mapped
Creek
corner
are much
while
oak scrub.
just prior
carry
broader
Another and more
in Happy
Creek
Tel 4 is dominated
pines
oaks
to
subdivision
aspects.
type
Another
fires
was
the land.
vegetation
of scrub
Many
rainfall
the fire under
period
during
1950.
probably
were
most
Robbins
and Myers
from
is by
important
and Happy through
Creek
has
the landscapes
and high flammability
Historical
climate
but, far below An ignition
Prior
1992).
imagery
records
Slight
is much
of pine
document
14).
July,
(lightning
strike
or man
dry periods
to moderate
47
August
fires
(Davidson increases
Scrub for a hot fire the
as a year with and September
induced)
in the above period,
but
just before
1950
June,
sometime
imagery,
evidence
average
conditions
during
(Figure
from a fire that occurred
to the fire suppression
extensive
from the 1943
fire and there
resulted
extreme
mapped
the 1951
openings
measurements.
started
openings
to time since
was taken. average
ridges
differences,
and farming
at Happy
Tel 4 in other
site has abundant
of these
homesteads
were
to be
was for a housing
vegetation
xeric
1950's
1935).
are related
to 1951.
imagery
sand
due to the low flammability (Webber
from
dominant
interspersed
Because
network,
and
did not appear
disturbance
differs
Creek's
is that the Tel 4 study
There
prior
with
Creek
had not purchased
landscape
interspersed
1940's
in the northwestern
with road
at Tel 4. The
with
vegetation
difference
more
ridges
largest
if NASA
is that Happy
oak scrub
mesic
Creek
the
a few scattered
that took place
built
during
land at Happy
The
complete
been
Creek
contained
et al. in press).
This clearing,
extensive
Most
and only
land clearing
that would
main
at Happy
probably
four
month
in xeric
scrub
and Bratton and decreases
1986, in open
Kilometers
6
o_
•
Open Scrub 1943
•
Open Scrub 1951
11o •
Open Scrub 1989
[]
Open Scrub 1943, 1951and 1989
Figure 14, The dynamics of open scrub in the Happy Creek study site on Kennedy Space Center.
48
space,
attributed
(Schmalzer and
to time since
and Hinkle
1958 were
The
in the amount
1960's,
fires
had
any conditions,
and other
have
openings
are far below
through
the landscape,
extreme
conditions.
edges
between
Forest occurring
the extent often
closed
cover
scrub
increased
from
found
on poorly
hardwoods Without
compete
with hardwoods.
through
through
frequent
these
the established
of the hardwood not slowed burned cover
high
in these
drained
sites
slightly
altered
drained
Most
of forest
intensity
into
in a few forested
when
sandy
natural
fires
extreme
swales. areas
with simple
into surrounding were
established,
fires
under
Naturally
and sedges
simply
swept
trails.
15).
spread
fire under
prescribed
spread
Prescribed
Today's
(Figure
became
was
and occasionally
or open
grasses
but they
burning
are now associated
soils
under
by roads,
returned.
season
in the
landscape
prescribed
to 1989
hardwoods
hardwoods
the process
with
1943
of a large
Beginning
and 1951,
grass
Occasional
composition.
unable fires
carry
conditions
resprout
with
around
these
A 1993
to
can burn
little alteration forests
restoration
and significantly
has fire
reduced
tree
areas.
Disturbed
scrub,
Once
oaks.
openings
Creek
fire, the swale
areas.
1980's,
the growing
and mowed
in 1943
was fragmented
in 1943
at Happy
before
oaks.
by fire suppression.
found
during
Openings
swales.
poorly
initiated
habitats
1958 was the start scrub
but few natural
trends
scrub
the KSC/MINWR
In the early
Creek
not reversed
surrounding
Creek
scrub
that
the landscape
firebreaks.
at Happy
shows
to burn across
after
within
at Happy
that surrounded
Creek
little chance
are expected
Openings
of openings
especially
implemented fires
mosaic
for Happy
decline
facilities,
1992 a, b).
a complex
imagery
the last fire,
sites
have
have
generally
composition.
revegetates
disturbed
often
been
returned
vegetated to scrub
by forests
or an oak scrub
Saw
palmetto,
which
areas
poorly
(Breininger
49
(Figure
carries
fires
16).
woodland through
and Schmalzer
Well with
oak 1990).
KilomeLers
6
o_
•
Forest 1943
•
Forest 1989
[]
Forest 1943and 1989
Figure 15, The dynamics of forest in the Happy Creek study site on Kennedy Space Center.
5O
Kilometers
6
o'.5
1.b
•
Cleared 1943 - 1989
•
Cleared-Forested 1989
Figure 16. Forest establishmenton previouslycleared areas in the Happy Creekstudy site on KennedySpaceCenter, Redareas were cleared between 1943and 1989but were not forestedin 1989.Green areas were cleared between1943and 1989and were forested in 1989,
51
The
relative
abundance
and Schmalzer perhaps
1990).
because
Happy
Creek,
of hardwood These
hydric trees,
_Unlike
suppression
Tel 4. Winter openings
2.4
and mesic
burned
length
(e.g.,
landscape
have
for recovery
rapidly
even
after
hurricanes)
to occur. a large
will be longer
and have
of breeding
restored
areas,
helping
breeders
Restoration population
does
approach
optimal
enhance
(Woolfenden
less
(Figure
chance
quickly. as well
will decrease
increase,
conditions
(Figure
providing 18).
52
upon
than
of natural
stochastic
which
must
numbers 17).
The
for successful Continued
they
the demographic
not rapidly
a longer
Creek.
will rebound population recovery,
decline
breeders
of breeders
by
1991).
extinction
risk
that most
Simulations
even
habitat
using
if
of helpers.
are potential
success
be
population
as the number
because
and Fitzpatrick
of the habitat
with
suitability
at Happy
population
effort
pairs,
to the population
and they
that
restoration
the number
patterns,
an abundance
suitability,
will reduce
Combined
in habitat
and habitat
is not implemented
of fire
effects.
depends
restoration
are important
period
recovery
aggressive
Helpers
a longer
Recovery
It is unlikely
scale
types
and swamps.
marshes.
forestation
At
by many
to swale
reduction
and Population
seeds.
of forests
not reestablished further
of pine
and vegetation
(Breininger
to clearings,
colonized
degradation
in a greater
not prevented
epidemics,
period
through
habitat
from
fires
were
characteristic
went
areas
differently
source
areas
of time for population
optimal
recovery
Creek
in disturbed
responded
in comparison
resulted
Restoration
The events
poorly
prescribed
and have
Habitat
by those
resulting period
differs
nearby
disturbed
had additional
discontinuities
also
was an abundant
especially
which
oaks
Tel 4 vegetation
Tel 4, Happy
suppression,
fire
The
there
hardwoods
fuels
of scrub
if the begins
empirical
to
for
Figure 17. Influence of habitat, helpers, and epidemics on population trajectories in habitat capable of supporting 700 breeding pairs after restoration. Assumes that habitat is restored to optimal or moderate suitability. Reproductive success and survival rates for optimal habitat derived from Woolfenden and Fitzpatrick (1984). Moderately suitable habitat vital rates were approximately midway between optimal and unburned habitat.
--e- Vital rates for optimal habitat, no catastrophes, helpers present in initial population. Vital
rates
for optimal
yearly probability restoration. -x--Vital
rates
epidemics present
of 0.05,
for habitat occur
in initial
habitat,
epidemics
no helpers
with
moderate
with a yearly
occur
present
habitat
probability
with
a
prior to
suitability,
of 0.05,
helpers
population.
8°°t 7OO
I.-
O. O) C
6O0
5OO ..Q v
40O
N cO
3OO
°p
"1 O 13_
2OO 100 0 0
10
20
30
Years
53
40
50
Figure 18. Reduction of extinction risk associated with restoration. Curves represent 1000 simulations beginning with a population size of 400 breeding pairs and assuming enough habitat to support a population of 700 breeding pairs. The risk curves represent the probability of falling below threshold population sizes any time during a 50 year period. The Happy Creek trajectory assumes currently
that reproductive occur at Happy
assumes
improvements
survival
rates
that optimal epidemics excluded.
remain habitat
occur
success and survival Creek. The moderately in habitat
5% below conditions
with a yearly
quality
but that
optimal. follow
remain the same as those suitable habitat trajectory reproductive
The optimal
a restoration
probability
0.05.
program. Other
success
habitat
trajectory Assumes
catastrophic
that
and assumes that
events
are
1 0.9 0.8 .B u .m
O
- ,L - Happy
0.7 0.6
rex--
Creek
(Optimal)
Archbold
Moderate
suitability
(-
.o
0.5
..I...i
t3 c"
°m
x iii
0.4 0.3 0.2 0.1 0 0
50
100 Threshold
150 population
54
200
250 size (breeding
300 pairs)
350
4OO
data
showed
that habitat
population
extinction
of KSC/MINWR
Even within
50 years
is inevitable
Florida
1% in optimal
habitat
habitat
optimal
Therefore,
habitat
low extinction
second
hurricane
of nearly
800 breeding habitat,
islands
A direct
19).
and that characteristic
to become
Extinction for large
probabilities
large
in A
an extinction
risk of
catastrophes).
by extensive
for a large
extinct
populations.
to have
and other
quickly
to manage
restoration
population
to the coastal
for a population
pairs
is unlikely.
size in order
result
could
to attain
given
5 storms
hurricanes
hit near Merritt
(Breininger
et al. unpublished
might
is nearly
Island/Cape
ms.).
(Figure
3 storms
Buckley,
Schuh,
& Jernigan,
contiguous
for 47 km.
ms.).
55
Total
storm
and all could
to inundate
during
size
surge
Half of the scrub
be needed
Canaveral
the maximum
risk of 1% in
20).
simulated.
is a
A population
an extinction
than
by category (Post,
5 storm
that scrub
to have
mortality
be inundated
of KSC/MINWR
size that approaches
are considered
in greater
hit by a category
proximity
et al. unpublished
is needed
hurricanes
by category
KSC/MINWR
remains
are likely
low only
hurricanes
size (Breininger
when
could
inundated
suitability
is essential
conditions
to manage
population
barrier
pairs
risk attributed
potential
inundation
persistence
risk.
reason
optimal
(Figure
are relatively
(without
it is important
The
habitat
populations
habitat
size of 400 breeding
Achieving
for population
if poor
Scrub-Jay
in poor quality
suitable
population
be optimal
scrub.
large
moderately
must
on
be
Inc.,
1990).
all of No catastrophic
the last 100 years
Figure 19. Influence of initial population size and habitat suitability on extinction risk. Quasi extinction probability refers to the chance that a population will decline below 10 pairs, a population size that usually involves extinction. Assumes that epidemics occur with a yearly probability of 0.05. Other catastrophic events are excluded.
-x-
Poor
quality
Moderate Optimal
quality quality
1.00
0.80 ..Q (0 JE)
o,9 t-J
0.60
tO O t..I-.,
X
0.40
(0
O
0.20
0.00 0
100
200 Initial
300 population
56
400 size (breeding
500 pairs)
600
700
Figure 20. Influence of initial population size optimal
habitat.
Quasi
extinction
population
will decline
extinction.
The frequency
yearly 63%
probablity mortality
1.00
below
probability
10 pairs,
of epidemics
of a catastrophic rate of all Florida
refers
on extinction
to the chance
a population
that
size that usually
is assumed
hurricane Scrub
and hurricanes
to be 0.01
involves The
resulting
Jays.
-
0.80
0.60
+
With
hurricane
+
No hurricane
mortality mortality
C
0.40
g, 0.20
0.00 0
1 O0
200 Initial
300 population
400
500
600
size (breeding
pairs)
5?
in
a
to be 0.05 per year.
is assumed
risk
700
800
in a
3.0 Strategic
One overall of 400-800 maintain
Florida the
with the goals
management
conservation
concern
high fuel
an interim
3.1
period
Criteria
Most persistence, habitat
Knowledge
will require
of extensive
of Reserve
Florida
restoration,
prescribed
be subdivided
based
and the potential restoration. on economic
will need
for habitat
proximity
to urban
estimated
based
A coarse
Sections
on current
and industrial on average
existing
information.
potential
reserves
of conservation use of prescribed
for species
fire safety
that result
that this effort
adaptive
fire
of
hazards
require
be
management
activities
existing
using
2.4 and 3.3).
undertaken
and ecological habitat
been
monitoring.
during
with
58
suitability,
sizes
based
and can be
can be developed
habitat
need
habitat.
of existing
soils,
habitat
be formulated
population
strategy
reserve
fine scale
fire management,
size and available
vegetation,
detailed
once
mechanical
can then
Expected
prepared
fires,
habitat
and without
designs
for population
Landscapes
potential
restoration,
areas.
prescribed
to prioritize
suitability,
reserve
only
condition
An adaptive,
to be established
territory
have
be in optimal
achieved
and conservation
Maps using
The
habitat
parallel
must
for mechanical
reserve
scrub
following
management
detailed
estimates
management.
numerous
habitat
burning,
Alternative,
of species
that is
Design
(see
process
ecosystem
and resources
and this is not readily
implementation
of the scrub
is to
restoration.
Scrub-Jay
is degraded
objective
needs
refinement
a core population
Another
C) and eliminate
successive
Recovery
habitat
of fuels
(Appendix
is to achieve
habitat.
tool will manage
Ioadings.
and involve
principles.
The
Plan
plan
and diversity
of KSC/MINWR.
coincide
phased
in optimal
integrity
as a primary
from
of this recovery
Scrub-Jays
biological
characteristic concern
objective
Recovery
landscapes
with and
and land use maps
to
(Huckle et al. 1974, Breininger et al. 1991 a, Larson 1992). Several principles for reserve designs can be immediately adapted using basic conservation science (Thomas et al. 1990, Noss 1991, Murphy 1992, Brussard and Murphy 1992, Murphy and Noon 1992, Noss and Cooperider 1994). Many of these principles apply to Florida Scrub-Jay conservation planning at state (Fitzpatrick et al. in press) and local (Brevard County) planning levels (R. Bowman, Archbold, unpublished, Swain et al. in preparation). 3.1.1
Provide
for a Large
A large
population
focused
on meeting
press).
Reproductive
precariously Florida exists
from should
include
3.1.2
Maintain
The vulnerable (i.e.,
must
the existing Even
impacts
the population
trajectories
landscapes.
the Northern
proximity
(Weiss program
on the population.
water
makes
and Murphy
1993).
and national
defense
and enhancing
decreases
The
combination
for a larger
population 59
resulting restoration
the population
this The
The topography region
potentially
location
makes
and nature
the population
the geographical
the risk of single
devastating
of KSC/MINWR,
CNS,
overall.
of the
Population
ms.).
table)
Maintaining
Scrub-Jays
makes
et al. unpublished
and shallow events
coast
of the
all habitat
much
Consequently,
Extent
to the Atlantic
(Breininger
for the space
provides
and Southem
of habitat
to return
changes,
scrub
of Florida
populations
given
by
Uncertainty
management
all major
to catastrophes.
distribution
decline
are
occupied
persistence.
be
et al. in
Scrub-Jays
size and the ability
with immediate
should
(Fitzpatrick
most habitat
for population
population
Efforts
of Florida
so that
the last half-century.
to climatic
vulnerable
rates
within
very low elevation
of operations
quality
of extinction.
populations
change
to hurricanes
vulnerable
and mortality
be optimal
may temporarily
landscape
for core
with habitat
conditions.
population
the probability
guidelines
success
balanced
concerning
to optimal
reduces
state
Scrub-Jays
Population
Evidence
and CCAS
suggests
that
demography varies among landscapes (Breininger et al. 1995); thus, some landscapes may be particularly important as population sources in comparison to other landscapes. This may relate to landscape configurations, predator populations, or other environmental factors. For these reasons, it is imperative to maintain the maximum north-south distribution of the population and the links to the Cape Canaveral population. 3.1.3
Maintain
Large
habitat
Scrub-Jays, adjacent
the Population
suitability sentinel
system
that
warnings
allow
Florida
1984,
then
(B. Stith,
unpublished
the best
3.1.4
when
formation Geological
data).
including
minimize
the amount
Margules
1993).
generally
north
by poor
by Keeping
of longitudinal
features
not forests, open
quality
surroundings habitat,
in large,
(Woolfenden have with
forests,
contiguous
have
landscapes
long distances
in their
developed
and
et al. 1991 ). Nonbreeders
Populations
of Merritt
formations
families,
from
habitat
a keenly
(McGowan
Large,
are often
greater
less risky
or development landscapes
thus
for long term survival.
Edge
geology
predators
vacancies
surrounded
chance
Minimize
The
breeding
by other
of Florida
Scrub-Jay
have
as hawks
numbers patches
on Florida
are nearby.
1991 ; Fitzpatrick
to detect
dispersal
such
hawks
to detect
fragmented
Scrub-Jays
surrounded
woodland
Scrub-Jays
Small,
Florida
Landscapes
the largest
influence
predators
Families
when
to maintain
a negative
for detecting
and Fitzpatrick opportunity
have
Contiguous
are equal.
et al. 1995).
1989).
early
are likely
factors
(Breininger
Woolfenden
have
patches
if all other to forests
in Large,
Island
ridges have
forests
of habitat
also
Orientation
Areas
and Cape
population
each
has resulted
parallel
In order
patch 6O
of other
to maximize
areas
should
landscape
total area
be elliptical
of the patches
as wide
in the
to the coastline.
the position
of the long axes
making
Wide
Canaveral
mostly
influenced
and roads.
of edge,
to south,
Reserve
(Sisk
should
as possible
and and
be
east to west.
Minimizing edge will reduce the number of territories along busy roads that are likely to have high mortality and will often be population sinks (Fitzpatrick et al. 1991, Dreschel et al. 1990). The proximity of scrub patches to forests should also be minimized, because populations near forests are subject to nest and adult predation. A long north-south axis maintains continuity across the KSC/MINWR population, and a wide east-west axis minimizes edge effects. 3.1.5
Maximize
Most drained
soils
occurred
et al. 1991
Nearly
interspersion
scrub
of woodlands,
and habitat
Scrub-Jays.
areas
soils
Matrix
of scrub areas
on well
(Woolfenden
population
and
in the mid-
on KSC/MINWR
components forests
for other
and other
species
they
due to low flammability which
and accumulate
a, b).
dominate
fuel
more
and Hartnett 1992
a, b).
for spreading
edges
Fires
prey
(Breininger
1990,
Thus, fires
burn
(Webber
than Myers
well
drained
marshes scrub
influence.
Native
for Florida
into wide
patches
of scrub
and marshes, oaks
the flammability into oak dominated
Schmalzer of native areas
1984
et al. 1991, matrix
habitats
that often
1987; oaks
gallberry
are more
(Abrahamson
matrix
Scrub-Jays
and Franz
Saw palmetto,
are
and serve
(Moler
1990,
61
landscapes
and swale
species
1935).
scrub
the
concern
palmetto-lyonia
rapidly
scrub
within
of negative
provide
that
minimize
areas
surround
of conservation
often
and grasses,
drained
that should
because
should
and industrial
Poorly
et al. 1994
important
consists
Scrub-Jay
management
forests,
Breininger
and Hinkle
the Necessary
drained
80% of the Florida
and habitat
are important
Abrahamson
on poorly
design
between
stop
habitat
300 m of well drained
landscape
habitats
Scrub-Jay
within
to Florida
as buffers
but Maintain
a).
Reserve
native
Scrub
Florida
with adjacent
1984).
important
Drained
high quality
Fitzpatrick 1980s
Well
burn
holly,
flammable a, b Schmalzer is poorly.
3.1.6
Keep
Patches
Contiguity Florida Stith
in Close
is important
Scrub-Jays
moving
unpublished
possible Small
data).
without
gaps,
woodlands, jays.
and poses
extreme Some
maintain
linkages
increase
Early
optimal
requirements continual accumulate. habitat
ecosystem Florida concern
(B. as
of water. for
is improbable
be as narrow
of habitat
as
will be required
to
quality
process
will
have ms).
the High
survival
of successful
and
restoration
decreases.
should focus Scrub-Jay
in the selected
Management
by managing
Breininger
on vegetation
species
occurs
required of Bald 62
finer
evaluate
scale
habitat will need
and populations the
of conservation
between
for
b).
efforts
in
and
1992
Recovery
to continually
overlap
and conditions
landscapes
persistence.
to other
the decline
landscapes
to identify
as data
will need
on reversing
in all major
1991,
will be needed
population
Much
quality
its associated
and risks
and Fitzpatrick
strategies
Costs
et al. unpublished
size and
costs
and modification
C).
corridors
(Breininger
population
this process
for long term
(Appendix
should
habitat
(Woolfenden
Scrub-Jays
habitat
bodies
or forests
of the highest
Restoration
processes.
of water
regions
populations
management
bodies
high
of
the risk of mortality
Restoration
of the Florida
The
is very
or large
increase
Mortality
be as contiguous
and Minimize
success
evaluation
should
Quality
as habitat
during
habitats
areas
in suitable
of restoration
habitat
Monitoring
large
risk.
all patches.
maximize
stable
non-scrub
development,
and urban
objectives
demographic establishing
as forests,
of persistence
success.
dispersal
the reserve
and less optimal
within
will
within
Gaps
Habitat
probability
reproductive efforts
risks.
it minimizes
mostly
across
among
Populations
quality
such
narrow
Maximize
habitat
through
Scrub
Dispersal
possible.
greatest
because
agriculture,
dispersing
3.1.7
Proximity
concern
conditions
for other
species
Eagle
(Haliaeetus
importance
optimal
of and for
of conservation leucocephalus)
nesting habitat requires additional considerations and priorities that need to be incorporated into alternative reserve designs. 3.2
Biogeographical
3.2.1
Population
Recent dominated reserve
habitat
units
(Table
landscapes
were Much
other
1, Figures areas
et al. 1991
700 territories,
Historical
forests.
(Larson
These
(Breininger
territory.
aerial
of poorly
landscapes soils
Canaveral
but it has been
photography
shows
may serve
marshes,
scrub
and few soils,
while
soils
in a
of well drained
et al. 1991
on mostly
of fire suppression.
Canaveral
for each
by well drained
scrub
of
show that these
Breininger
by coastal
for the
a population
is needed
conditions
patches
as scrub
potential
provide
openings,
et al. 1974,
to 40 years
Cape
could
is dominated
was dominated
that
many
include
(Huckle
subject
areas
and edaphic with
landscapes
habitat
10 ha of scrub
photographs
landscape
four
22) which
the highest
These
assuming
of the Shiloh
identified
21, Figure
a).
by scrub
drained
1992)
have
dominated
KSC/MINWR
Cape soils,
mapping
(SRUs).
approximately
matrix
Centers
by scrub
population
most
Considerations
well
drained
Historical
had many
openings
supported
much
a).
aerial
and few
trees.
The
adjacent
well drained
scrub
destruction.
Scrub
long unburned
Florida than
is no realistic
those
on KSC/MINWR
mainland
from
on the Florida
present,
mainland
(Snodgrass potential
Merritt mainland
to link mainland expanses
and the extent
(Swain
was decimated
now occurs
et al. 1991,
due to wide Island
originally
but this scrub
on the Florida
habitat
There
mainland
Larson Florida of open
of scrub
et al. in preparation).
63
more
by habitat
as patches 1992,
Bergen
Scrub-Jay water
extensive
of mostly 1994).
populations
that separate
destruction
with the
and degradation
o
0
=-
o
II r_
8
CO
"5
#
_o 8
o_
o "o
_g
_m
mn, I-CO
64
Figure 21. Potential scrub habitat on John F. Kennedy Center/Merritt Island National Wildlife Refuge, Cape Air Station
and adjacent
lands.
65
Space Canaveral
\
km 0
Figure
22.
3
Scrub
SRU: 1-Shiloh, Corridors:
6
reserve II- Happy
a-Haulover,
units Creek, b-Banana
(SRUs)
and corridors.
III-Schwartz Creek,
Road,
c-Cape
66
Roman
numerals
and IV-Southern
Canaveral,
indicate pinelands.
and d-Industrial
Area.
cores.
3.2.2
Linkages
A narrow Space
corridor
Shuttle
Complexes
(i.e.,
exists
a vital
link between
is also
important
of occupied
LC39A
and LC39B)
between
KSC/MINWR
SRUs
linkages
scrub
between
most
northern
the Happy
Creek
area
with the Shiloh
open
water,
crossed
immediately several made
south
occasions
Canal
(R. Schaub
personal
Much
birds.
the canal
for urban
acquired
soil disturbance
expanses
of severely
freezes, grape 1994),
groves have
vines
not native
The Happy
most
Creek
and cabbage
scrub
plants.
corridor
area to the Schwartz
fragmented
3.5).
These
and shrub
Several
palms
to establish Road
67
were
not
the
are known
by citrus occurred
ceased
land clearing
habitat
on
to
data).
development
by native
spp.),
difficult
dispersals
with
to be farmed.
crossings likely
of
the area
the canal
long distance
urban
scrub
dominated
crossing
through
expanse
occupying
These
connects
Movement
and were
has been
associated
22).
attempt
(Section
Although
continue
become (Vitis
corridor
degraded
seen
unpublished
development
the land.
been
is
require
which
is a 90 m wide
observation).
three
(R. Schaub
purchase,
the citrus
Also,
corridor
Scrub-Jays
or as a dispersal
of the Haulover
land cleared NASA
defense
have
This
22); this corridor
on KSC/MINWR
(Figure
which
Florida
of Haulover
of young
crossed
Canal
et al. 1993).
concern.
is the Haulover
landscape
the
and LC41)
(Figure
of conservation
of these
Haulover
(Larson
units
surrounding
LC40
and CCAS
reserve
by a drawbridge.
for territorial
wanderings have
crossing
habitat
(i.e.,
and CCAS
scrub
The
requires
and Titan
species
restoration.
this area
Scrub-Jay
on KSC/MINWR
for other
Several
Florida
groves,
has resulted and brush abandoned
and introduced (Sabal
involves
landscape.
after
grasses
palmetto)
and
before NASA's in land.
Most
after
hard
and forbs,
(Schmalzer
the connection Movement
groves
et al.
of the
between
these
of
areas involves crossing about 3.5 km of peripheral impoundments, open water of Banana Creek, and industry associated with the LC39 area (Figure 22). The landscape to the west of SR 3 includes Banana Creek that is hundreds of meters wide and is bordered by wide marshes on either side. The only possible connections occur along the crawlerway, barge canal, islands, and peninsulas that extend into Banana Creek. The best connection between Schwartz Road and the Southern Pinelands occurs near the western shore of the Banana River through an area of scrub that has been unburned for greater than 20 years and is outside BUs (Figure 22). The only unavoidable discontinuity is the busy, two lane NASA Parkway (SR 405) and its grassy edges. The connection between these two major landscapes could be widened readily by pine thinning and burning in areas outside BUs north and south of NASA Parkway. Although risky, dispersal can occur across four lane roadways (i.e., SR 405) and industrial areas dominated by buildings, landscaped trees and shrubs, parking lots, and large grassy areas. Potential for a permanent connection between KSC/MINWRJCCAS/CNS and Florida Scrub-Jay populations outside the federal boundaries is unlikely. There are less than 20 territories remaining on Merritt Island near the south boundary of KSC/MINWR (Swain et al. in preparation). These territories occur in small patches of habitat with no hope of population persistence except for those adjacent to the Southern Pineland area. Some scrub adjacent to the Southern Pinelands has been purchased by the Brevard County Environmentally Endangered Lands Program as the Kabboord Sanctuary, and it could support several territories. The other scattered territories on Merritt Island have been excluded from the reserve design for the Brevard County Habitat Conservation Plan (Swain et al. in preparation).
68
3.3
Restoration
Activities
Small
habitat
scale
implemented scrub
restoration
(Schmalzer
vegetation
not be known
for decades, groves
mechanical
treatment
landscape
techniques
should
mechanical
techniques
which
required
in many
trees
should
techniques
areas,
territories
efforts
not reestablish
xeric
woodlands
efforts
will
in include
into an open
scrub
Scrub-Jays.
to be greatly
increased.
in soil disturbance Although
and in areas
planting
of these
restoration
BUs or other
edges
include
Other
can be accomplished
along
and
on fire with cautious
1990).
by fire within
will be useful
scrub will
fire needs
may result
planned
efforts
of Florida
rely mostly
much
be thinned
that
to convert
and Schmalzer
been
The success
efforts.
of prescribed
Restoration
(Breininger
groves.
intensive
and burning
application
of fuels
citrus
to support
have
Experimental
but it is clear
without
suitable
The
et al. 1994).
in abandoned
abandoned
efforts
use of
and a discontinuity
mechanical using burn
techniques
prescribed
areas.
that have
fire.
are Pine
Mechanical had extensive
soil
disturbance.
3.3.1
Mechanical
and
Mechanical and other
tree
cutting
at these
cutter,
unpublished).
produced
that
et al. 1994).
Brown
treated
techniques
vegetation
(Schmalzer
with
but the oaks,
Techniques
have
have
sites.
the Brown
been
grown
tree cutter
in several
techniques
landscapes
have
and other and prescribed
resulting and other
been
shrubs fire.
in an increase shrubs
69
to cut oaks
by burning have
and V blade.
responses
saw palmettos,
saw palmettos,
cutting
K-G blade,
Vegetation
soil disturbance
used
too tall to be restored
Experimental
rollerchopper,
Oaks,
more
Burning
involved
Burning promising
resprouted Some
the
has followed (P. Schmalzer in areas
techniques
in herbaceous
are recovering.
alone
weeds,
Florida Scrub-Jays have actively used restored areas for foraging, caching acorns, and even nesting within 18 months postfire. However, most restored areas have been too small relative to the overall landscape and the period after restoration too short to judge demographic success. Given the large size of Florida Scrub-Jay territories, it is clear that restoration activities must occur across entire landscapes. 3.3.2
Restoration
Burning
Many
can be restored
areas
with spatially
explicit
objectives.
burning
every
8-20
Menges
et al. in prep.).
KSC/MINWR
shrub
height.
desired
a 15 year
Prescribed burning
These
within
cycle
fire for scrub more
should
prescriptions
management
for Lake
mean
scrub
smaller
on standard
mainland.
fire and
existing
is
et al. 1991,
pine trees
intense
and
scrub
considered
to thin
than
ridge
restoration
on the Florida
be used
frequency
(Fitzpatrick
than
may require areas
Wales
habitat
frequently
drained
for restoration
fire at an increased
A standard
of excessively
fires
conducted
with
will require
the maintenance prescribed
years
by using
for
Initial
and reduce may need
to be
BUs to achieve
results.
"Hard" should
fire lines
be made
undesirable openings
fuel
are needed
to minimize
can be searched
fire
soil disturbance
discontinuities
is preferable
to control
systematically
edges,
in some
that has been
and subsequent
to artificial
spread
forestation.
such
by predators
associated A natural
as fire breaks of Florida
areas.
Efforts with mosaic
and roadsides,
Scrub-Jay
nests
of that
and
adults.
Seasonal summer Myers
fires 1992).
pinelands
variation
to mimic The
in prescribed
historical
recovery
by allowing
snags
fire
fire patterns
of open
space
and downed
7O
involving will
also
the
increased
be needed
can be performed trees
to burn.
use of (Robbins
more
However,
easily allowing
and in these
to burn creates potential smoke problems for roadways, urban areas, NASA, and CCAS operations. The recovery of openings in scrub may be difficult herbicides.
A long term
openings. reduce
to establish
Initial
frequent
biomass
needs
to be dead
between
four
for oak scrub
between
burns
Extremely conducted These
Florida
get them
(less
need
Many
oaks
areas
especially
when
in
at least three
minimum
to
time
burning.
200 ha), burns
landscapes
(e.g.,
conditions
should
Happy
success
stature
be
Creek).
and investigate
to burn the same
at sufficient
burn
This
for reproductive
are not intended
obs.)
and at least
using
than
optimal
essential
is important
Thus,
openings
small
in enough
(F. Adrian
are required.
to
exact
fine
to exceed patches
each
and age for acorns,
poorly
so that repeated
considering
the operational
fires
are needed
complexities
to
of
management.
A variety restoration intense
to restore
of ignition
fires. head
Ignition
fires
implemented.
devices
to create
are needed
ground
palmetto
or
to reestablish
reserves
pers.
It
techniques
years
to live fuels
difficult.
that 25% of the above
palmetto
towards
needs
Scrub-Jays
to burn,
fire
in a few experimental
burns
and cover.
ratio of dead
sparse
restoration
for 10-15
with abundant
usually
restoration
Yearly
nesting,
with
the speed
year
can expedite habitat
in areas
mechanical
carbohydrate
It appears
is more
will be needed
2-4 years)
for effective
specific,
each
mortality.
smoke
burns
limits
The
to burn.
two years years
(every
to return.
able to get areas
time.
fires
pine trees
without
approach
of underground
for openings
being
quickly
experimental
the accumulation
patches
scale
openings
without
strips
Narrow
stripped, scrub.
or a heli-torch
and prescriptions
of mechanically
that can penetrate
overgrown (DAIDs)
techniques
flank Aerial
should
chopped
fine fuels
tall, long unburned fires ignition,
can produce using
may be necessary
71
be used
to produce
oak patches the fire intensity
delayed
aerial
for burning
in early
have
been
required
incendiary
patches
that are
not easily accessible or pose a safety threat due to fuel loads or burning conditions. A heli-torch would be more effective than DAIDs at igniting areas that do not carry fire because of fuel discontinuity (Adrian and Farinetti 1995). 3.4
Habitat
only
Quality
Detailed
mapping
in long term
study
al. 1995 a), although KSC/MINWR
a, Larson
1992).
are being
varies
term
(Provancha
et al. 1986,
demographic
(Breininger
local
efforts
throughout in which
KSC/MINWR.
Habitat habitat
to identify areas
soils, fire history, development.
large
areas
Duncan
Breininger
Scrubsuccess
in preparation; that
modeling (Duncan
for
et al. 1991
Florida
effort
et
developed
demographic
intensive
suitability
been
banded
Scrub-Jay
require
Habitat over
on color
et al. 1995,
(Section
2, Figure
and Restoration quality
Duncan
is not
is approaching
et al. 1995
a
a,
23).
BUs and along edges
inventories
have
3.5) to assess quality
Degradation
been
and severe
of woodlands
and more detailed
of habitat
Costs
of disturbance
the presence
These
Initial analyses
and forests
Florida
have
performed
et al. in preparation).
Preliminary
inventories
scale
it can be applied
Degraded
resolution
how
data
has been
in preparation;
habitat
conditions
These
quality
of potential
with landscape
Breininger
(Table
maps
habitat
et al. 1995,
to evaluate
feasible
3.4.1
(Breininger
landscape
Long
Scrub-Jay
used
et alo 1995 a).
phase
areas several
the entire
Jays
of Florida
57%
is widespread
of BUs, facilities,
often do not burn effectively
because
72
using
and the proximity
of
with population
structure
present
today.
of the scrub is degraded
in areas
and forests.
at coarse
degradation
can be coupled
the metapopulation that
habitat
and forests,
studies
indicate
conducted
Edges
excluded
from
of BUs, facilities,
of their fuels
structure
or
.8o E
8
3
n,'
o'3 c
"5
c-
_5 e4
1--00
73
i.
km 0 Figure units,
23.
Disturbed
(2) within
or forested
3
land,
6
_.
and degraded
300 meters or (4) within
scrub.
of facilities, regions
7 Defined (3) within
of scrub
74
:| as scrub: 100 meters
having
a dense
:.._ I (1) outside of urban Florida
of bum land
slash
pine canopy.
deliberate
fire suppression
hazardous. estimate
These
mechanical
difficult
to initiate
Areas
dominated
sales.
However,
monitoring
costs
within
costs
can
hectares
associated further
Most
costs
thinning
the proposed
require
increased
fire frequency
cover.
This
is approximately
There willows Many
and wax myrtle
hammocks, because edge
habitat
3.5
within impact
3080
habitats
have fragmented
Population
Scrub-Jay
KSC/MINWR.
The
wide
timber and
cutting
The exact
are difficult
of oaks number
of
to determine
that is not severely openings
degraded
and decrease
will
tree
and 306 ha of marshes
become
landscape,
populations
hammocks.
need
population
restoration
by
activities.
Some
extensive
centers
occupied
fire and cutting
with too much
forest
to be successful.
Inventory
150 families
center
using
mechanical
fire and other
have
potential
Approximately
(Figure
of the trees.
ha.
habitat
in the native
for Florida
investigation quality,
marsh/swale
assessments,
reserve
that need frequent
not present they
will be
implementing,
actions
fires to produce
are 571 ha of disturbed
historical
treatment
with time and equipment. restoration
to
fire with or
areas
activities
for planning, The
frequent
of these
by logging
can be used
to the population.
that need
mechanical
operations.
habitat
critical
in most
prior
may be considered
inventories.
within
scrub
scrub
fires
incurred
with specific
scrub
initial
be thinned
associated
habitat
and corridors
without
are also
of commercial many
The
control
by pines
will incur
SRUs
fire or smoke
and degraded
ha of degraded
treatment. and/or
where
of disturbed
is at least 4100
without
without
inventories
restoration
There
near facilities
study
restoration 2).
Because
territory
of Florida areas
Scrub-Jays
include
activities,
and long-term
of the extent
censusing
territories
investigation
monitored
for short-term
(e.g.,
and variation
has not previously 75
are under
3-8 years)
in scrub
conducted.
habitat As habitat
quality and population estimates continue to decline, center wide surveys of jay territories
are needed.
Secondary areas
efforts
of poor
will focus
quality
The overall accurately
censuses
should
on territories
that exist
have
used
accuracy
to survey
(Fitzpatrick
et al. in press).
that that Florida
Scrub-Jays
occupy
Florida
that all habitat Scrub-Jay
The number initiation
3.5.1
territorial
of territorial
and
Scrub-Jay
Florida
scrub
was a visual
biologists
surveying
and other
were
remain
with a resident
adjacent
group.
During
territorial
calls
After
finding
both
biologists
allowed
calls
m from while
the adjacent were
biologists
Inventory while
satisfied
to be aware
unpublished
often
away
that they of group
on the
occupation
occupying
territories
activities
group, under
groups.
(e.g.,
direction
calls
for the
began
kept under
within
that one
searched
from the group
two
of territorial
required
biologist
were
Because
to have
protocols
had separate
76
data).
of the resident
groups
for the Shiloh
to a playbacks
the second
both
based
necessary
the second
the position
group,
occupancy.
habitat
was conducted
to respond
moving
that imply
of
Inventory
Scrub-Jays
group
is
1984)o
Florida slow
Scrub-Jay
and the playback
to be estimated
behaviors
more
on KSC/MINWR,
need
(R. Schaub
the inventory,
at 50-70
territorial
and in
to be considered
for determining
it was
observation).
biologist
playing
SRUs.
regions
Florida
methods
barrier,
often
soils
searches
inventory
in 1995
together.
personal
provide
Scrub-Jay
overgrown
(R. Schaub
Visual
Population
corridor
scrub
drained
and Fitzpatrick
Haulover
tall, unburned
within
population
to the statewide
territories
disputes,
and Haulover
A complete SRU
calls
(Woolfenden
Shiloh
linkage
One difference
poorly
be surveyed.
of Florida
and ownership
within
areas
the KSC/MINWR
comparable
project
requiring
first target
habitat.
approach
should
mapping
Territory
playing
the
and continued observation.
observation Two-way
until radios
and distance
of
travel). Repeated visits were made at sites where no Florida Scrub-Jays were detected. Estimates of the potential population size (breeding pairs) were made from inventories of potential habitat, which includes available scrub, disturbed shrub and brush, abandoned citrus groves, and conifer plantations that are contiguous with scrub cover types. These later cover types are considered potential habitat because they have the potential to be restored. An additional estimate was made of the historical population size based on potential habitat and active citrus groves that are contiguous with potential habitat. Comparisons of field inventories and estimates based on habitat indicate that the population has declined severely throughout the Shiloh SRU. The number of breeding pairs in the Shiloh SRU is at 40% carrying capacity (total number of breeding pairs based on potential habitat), with some burn units at less than 25% capacity (Table 3). Much of the available habitat (at 46% capacity) is also unoccupied because of fire suppression and forestation. There is little active citrus in this area. Restoration of available scrub, without the more difficult restoration of disturbed areas (disturbed shrub and brush, abandoned citrus and pine plantations), could provide habitat for 87 territories. Analysis of data from the Haulover corridor suggested a high density of Florida Scrub-Jay groups relative to the amount of available scrub (Table 3). However, many of the Florida Scrub-Jay groups in this region occupied disturbed shrub and brush (where the dominant vegetation includes cabbage palms, wax myrtle, and Brazilian pepper). These disturbed areas resulted from land clearing associated with residential development prior to NASA acquisition. Much of the current scrub is excessively overgrown and not occupied by ScrubJays. Although the disturbed areas have low suitability, they contain some scrub oaks, patches of low growing vegetation, and open sandy areas. These later
77
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