density, dispersal ability, and minimum viable population. (MVP), to identify landscapes harboring sufficient habitat to meet the needs of viable populations.
Prioritization of Pine Habitat for Landbird Conservation in West Gulf Coastal Plain and Ouachita Mountains Daniel J. Twedt , Amy K.
2 Keister ,
S. Keith
2 McKnight ,
and John M.
3 Tirpak
U.S. Geological Survey, Patuxent Wildlife Research Center, 2Lower Mississippi Valley Joint Venture Office; 3Gulf Coastal Plains and Ozarks Landscape Conservation Cooperative, Vicksburg, MS 39180
OBJECTIVE We sought to identify all landscapes in the West Gulf Coastal Plain with sufficient area of pine or pine-hardwood forest to support viable populations of priority bird species associated with open-pine habitats – provided these forests were managed to achieve and maintain open-pine conditions.
Species Red-cockaded woodpecker Bachman’s sparrow Northern bobwhite Brown-headed nuthatch
Density (ha/pair) 50 3 20 3
The patches in this cluster are close enough for dispersal.
Remove all forest in floodplains (colored blue) .
Suitability Ranking
Ranking of 811 red-cockaded woodpecker clusters: mean = 295; SD = 108
Habitat Dispersal ½ dispersal required distance distance (ha) (km) (km) 1,000 8 4 150 3 1.5 1,200 1.8 0.9 84 0.92 0.46
This cluster of 1,472 ha of existing evergreen and mixed forest was deemed capable of supporting a minimum viable population (≥20 pairs) of Red-cockaded Woodpeckers if habitat were to be maintained in suitable open-pine condition.
These patches are not close enough to another patch for dispersal.
Identify all forests with pine from National Land Cover Data.
MVP (pairs) 20 50 60 28
OPEN PINE LANDSCAPE SUITABILITY
Number of clusters
INTRODUCTION Throughout the southeastern United States, open-canopy pine, especially long-leaf pine, habitat has diminished in area and distribution. Characterized by low basal area or canopy cover of mature pines and a grass or herbaceous understory maintained by fire, open-pine habitats often support unique yet declining flora and fauna. We used digital geographic information to identify areas of pine or mixed pine-hardwood in the West Gulf Coastal Plain/Ouachita Mountains Bird Conservation Region. These sites were deemed capable of supporting viable populations of priority bird species, including Red-cockaded Woodpecker, Bachman’s Sparrow, Northern Bobwhite and Brown-headed Nuthatch, if suitable basal area is achieved by silvicultural treatment and maintained by fire. These open-pine birds differ in breeding density, dispersal capability, and association with structural habitat which affects suitability of landscapes to support their populations.
Remove patches that cannot support ≥1 breeding pair.
METHODS For 4 priority bird species, we used geospatial data for 2001 land cover and elevation topography, combined with published estimates of each species breeding density, dispersal ability, and minimum viable population (MVP), to identify landscapes harboring sufficient habitat to meet the needs of viable populations. Population sustainability was presumed to be depended upon suitable management of forest for open-pine conditions as maintained via prescribed burning.
Determine which patches allow dispersal between patches
Groups of patches are ranked by area (ha).
We thank the participants of the West Gulf Coastal Plain Landbirds Working Group, especially chairman Eric Baka, Louisiana Department of Wildlife and Fisheries, for their assistance in development and review of this decision support model .
- Minimum value = ha required for one pair - Groups that support ≥MVP assigned maximum value = area supporting a MVP.
High: 400 Low: 0 RESULTS For each species, we normalized landscape values by dividing each species’ habitat raster by their respective MVP, thereby changing units from ha to % of MVP . We summed % MVP values for each of the 4 priority species evaluated to achieve a regional suitability model open-pine birds (range = 0 – 400). CONCLUSIONS When models for each of the 4 species were combined, the resultant depiction provides guidance to support management decisions regarding allocation of resources for long-term management of open-canopy pine ecosystems within the West Gulf Coastal Plain and Ouachita Mountains Bird Conservation Region.
