Wilderness permit accuracy - Springer Link

Wilderness PermitAccuracy: Differences between Reported and Actual Use DAVID J. PARSONS THOMAS J. STOHLGREN National Park Service Sequoia and Kings Canyon National Parks Three Rivers, California 93271 JAMES M. KRAUSHAAR School of Business University of Vermont Burlington, Vermont 05405 ABSTRACT / Wilderness permits are valuable tools for recording backcountry use patterns. They provide a valuable basis upon

The increasing use of wilderness areas in recent years has made it essential to understand the levels, patterns, and distribution of visitor use as well as the associated impacts of such use on the wilderness resource. Mandatory wilderness permits provide an effective means of obtaining use information, while at the same time assuring public contact, providing opportunities for minimum impact education, and facilitating enforcement of use restrictions (Hendee and Lucas 1973, Hendee and others 1978). Such permits are now widely used, being required by most wilderness-type areas in both the United States and Canada (Lime and Buchman 1974, Hendee and others 1978). Public acceptance of mandatory wilderness permits has proven to be high (Fazio and Gilbert 1974, Kantola 1976), with compliance rates frequently above 90 percent (Hendee and others 1978). Despite the general acceptance of the wilderness permit as a valuable tool for gathering visitor use information, recent studies in Yosemite (van Wagtendonk and Benedict 1980) and Mt. McKinley (Plager and Womble 1981) National Parks confirm the suspicion (Hendee and others 1978) that the accuracy of the use estimates they generate can vary considerably. This can result from either failure to obtain a permit (Lime and Lorence 1974) or changing one's plans after a permit has been obtained (van Wagtendonk and Benedict 1980). If wilderness permit data is to be used as a basis for making management decisions (for example, determining or enforcing use restrictions, evaluating impacts of different use levels, or scheduling trailhead or patrol personnel) it is important to understand the extent and magnitude of inaccuracies in such reported data. In this paper we evaluate the possible sources of error in EnvironmentalManagement,Vel.6, No. 4, pp. 329-335

which management decisions are made. Unfortunately, significant inaccuracies in reporting permit data result from noncompliance, transmission errors, and changes in visitor plans. Data from Sequoia and Kings Canyon National Parks in California show that in 1978, 97 percent of the parties obtained wilderness permits. Changes in visitor plans resulted in an over-reporting of total persons by 8 percent and of visitor nights by 23 percent. The latter was due primarily to shortening of trip length. Over-reporting was greatest when permits were issued well in advance of the trip. Backcountry managers should be aware of possible inaccuracies in permit data and may want to adjust for them under certain circumstances.

wilderness permit data and then examine the extent and magnitude of such errors for one selected wilderness area, Sequoia and Kings Canyon National Parks in California. We also discuss means by which wilderness managers can incorporate knowledge of inaccuracies in permit data into their management program.

Sources of Permit Inaccuracies Inaccuracy in wilderness permit information can come from a number of sources. These include the failure to obtain a permit (noncompliance), errors in filling out the permit (transmission error), and changes in visitor plans (regardless of whether or not transmission errors were made). Each source of error and its potential effect on the magnitude and distribution of the difference between reported and actual use is illustrated in Figure 1. It is possible, but not likely, that when two types of errors are made on the same permitthey may compensate for each other. Compliance

Compliance with the requirement to obtain a permit before travelling into a wilderness area has generally been reported as quite high. Studies in the Boundary Waters Canoe Wilderness in Minnesota (Lime and Lorence 1974), Yosemite (van Wagtendonk and Benedict 1980) and Mt. McKinley (Plager and Womble 1981) National Parks have all reported that 88 to 93 percent o f the parties obtain wilderness permits. To the extent it occurs, noncompliance will contribute to an under-reporting of the total number of parties, number o f persons, and visitor nights, as well as probable changes 0364-152X/82/0006-0329 $01.40 9 1982Springer-VerlagNewYorRInc.

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~ J. Parsons and others

SOURCESOF ERROR

EFFECTONVISITORUSE USELEVELOVER 9 ORUNDER-REPORTED; USEDISTRIBUTIONALTERED

[

YES

~

N

O

NO

N ~ [O YES

9 OR USEUNDER-REPORTED; LEVELOVER ALTERED USE DISTRIBUTION

u II~

I

I. NOEFFECT

visitors may allow an alternative trailhead to be entered o n the permit if the quota for their first choice trailhead is full, even though they intend to stick to their original plans. This type of behavior is one possible negative consequence o f using permits as both rationing devices a n d sources of information (H. Vaux personal communication). Also, without adequate training or strict issuing controls, permit information can be omitted or entered incorrectly by the issuer. This becomes a special problem when a large n u m b e r of parties are waiting for a permit a n d time is limited. No data are available on the extent or magnitude of transmission errors.

Changes in Visitor Plans

20I

USELEVELUNDER-REPORTED l=USEDISTRIBUTIONALTERED

Figure 1. Sources of error in use reporting from wilderness permits. The effect of each type of error on reported total use and on differences in the distribution or pattern of reported versus actual use is presented. Once a transmission error is made, changes in plans ran either compensate for or further compound effects on reported use.

in the reported distribution of use. With two recent exceptions (van Wagtendonk and Benedict 1980, Plager a n d Womble 1981) little data are available to document the similarities a n d differences in use distribution between noncompliers and compliers. T h e limited informarion available suggests that noncompliers tend to stay s h o r t e r periods of time and be members of smaller groups than do those who obtain permits (Vaux 1975, van Wagtendonk and Benedict 1980). Where noncompliance is a major problem it may be necessary to conduct special surveys to document use characteristics of such parties. O t h e r sources of compliance error relate to the possibility of more than one member of a party obtaining a permit for the same trip or, where permits are issued well in advance, obtaining two or more permits for alternate trailheads or dates for the same trip. T o date no one has investigated the extent to which such overcompliance a n d consequent overreporting of use occurs.

Permit Transmission Permit transmission errors occur when the visitor's plans are not entered correctly on the permit. This can occur either when the visitor gives incorrect information to the issuer (whether intentional or not) or the issuer places incorrect information o n the permit. For example,

Inaccuracy in permit data due to changes in visitor plans results when changes are made in the planned trip itinerary after the permit has been issued. Since wilderness permits are either filled out at the start of the trip, or in a few cases even months before the trip begins (for example, lnyo National Forest in California), there may be significant differences between planned or reported use and actual use. Visitors may alter their route a n d / o r shorten or lengthen their trip. Such changes may be by choice or may be forced by inclement weather, physical or health problems, over or u n d e r estimation of physical capabilities, or loss of food to bears or rodents. T h e potential significance of such itinerary changes is illustrated in Yosemite National Park where van W a g e n d o n k and Benedict (1980) found 62 percent of the parties interviewed made some change in their projected route or trip length. I n those cases, such as on the Inyo National Forest in California,.where permits are filled out and mailed as m u c h as five months before the trip there is no way of knowing whether the trip is even taken. In this case the permit information would report nonexistent use. U n d e r such a system, even if the trip is taken there is an increased chance of changes in itinerary, length of stay, a n d party size. Such a practice can result in considerable over-reporting of use and should be discouraged. T h e p r e f e r r e d system, now practiced in most wilderness areas, allows for reservations to be made well in advance but the permit is not actually issued until the party shows u p ready to depart. This assures the trip is taken and reduces the chances for itinerary changes while still assuring the visitor that a permit will be available. Changes in visitor plans result in differences between reported a n d actual use. These differences may affect b o t h the magnitude of use and its spatial distribution. Magnitude changes occur when planned length of stay or

WildernessPermitAccuracy

group size is not the same as actual. These may result in either under or over-reporting. Changes in distribution of use occur when itineraries are changed so that planned travel zones visited or trailheads used are not the same as actual. While changes in use distribution may also result in magnitude changes this is not always the case. For example, if a group spends an extra night in one zone but one less night than planned in another zone and makes no other changes in their itinerary there will be a change in use distribution but not magnitude. Changes in visitor plans occur whether or not transmission errors have been previously made. In those cases where both types of inaccuracies occur, the error may be either compounded or offsetting. Whenever management decisions are to be based on reported use from wilderness permits it is essential that managers understand the extent of potential data inaccuracies. Unfortunately the magnitude of such errors in use reporting will likely show some temporal variation. For example, local weather conditions, a late snow pack, or periods of high bear activity can all create highly variable, unpredictable fluctuations in the accuracy of reported permit data. And thus while it may not be possible to monitor or even understand all possible causes and fluctuations in permit inaccuracy, it is important to recognize the conditions under which such might occur as well as to understand the potential effects on the difference between reported and actual use. In the following section we report the findings of a study on permit compliance and changes in travel plans during a peak use period in a remote mountain wilderness area.

Accuracy of Permit Data in Sequoia and Kings Canyon National Parks Sequoia and Kings Canyon National Parks occupy an area o f 349,457 ha in the southern Sierra Nevada of California. The parks, which span an elevation of from 425 m to 4,421 m, are managed almost entirely as undesignated wilderness. Sixty-seven trailheads, located both within the parks and on adjacent US Forest Service land (Inyo, Sequoia, and Sierra National Forests) provide backcountry use of the parks. Wilderness permits have been required for backcountry travel since 1971 and daily trailhead quotas based on acceptable impact levels (Parsons and others 1981) have been enforced since 1973. Up to 50 percent of each day's trailhead quota may be reserved in advance although all permits are issued only in person and within 24 hours of trip departure.

331

The exception to this is that reservations issued by the Inyo National Forest for trailheads on the east side of the parks may occupy the entire quota and the permits are mailed out at the time the reservation is made. Most of the permits issued by the Inyo fall in this category. They constitute as much as 50 percent of the permits issued for overnight travel in the two Parks. Over the five year period 1976 -1980 a yearly average o f 13,854 parties were reported as entering the backcountry of Sequoia and Kings Canyon National Parks from wilderness permit data. These parties consisted of a yearly average of 43,025 persons who contributed 176,741 visitor nights. Average party size was 3.2 and average length of stay was 4.3 nights per party. The fact that the latter is nearly half again as long as the 2.9 nights experienced in Yosemite (van Wagtendonk and Benedict 1980), documents a significant difference in the nature of backcountry travel in the two areas. In Sequoia and Kings Canyon, 83 percent of the parties number less than 5 persons, while less that 2 percent consist of over 15 persons (maximum allowed party size is 25). Ninety-seven percent or more of all backcountry use consists of foot travel by backpackers. A relatively small number of parties rides or .transports their gear on horses or mules.

Methods In order to understand the accuracy of data reported from wilderness permits issued for travel in Sequoia and Kings Canyon National Parks we sampled visitors exiting the parks' backcountry during the heavy use period of August 17 to August 24, 1978. The fourteen most heavily used trailheads, consistently representing 70 percent or more of the parks' backcountry visitors, were each sampled for seven days during the study period. All parties exiting the sampled traflheads between 8:00 am and 6:00 pm were contacted by uniformed park personnel either at the trailhead or at the park boundary (when trailheads were on Forest Service land). Discussions with party members were used to record daily trip itineraries. This data was compared with the projected itinerary that had been entered on the wilderness permit at the start of the trip. Data analysis consisted of comparing recorded and actual trip itineraries. Separate analyses were made of permits issued in person at the trailhead (west side) and those issued either in advance or at a centralized issuing point (east side). The Statistical Package for the Social Sciences (Nie and others 1975) was used for most data analysis. A special FORTRAN program was written to analyze the travel zone portion of the data.

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D.J. Parsonsand others

Data analyzed included whether the party had a permit, obvious data omissions in filling out the permit, and differences between reported (that is, permit) and actual group size, length of stay, total visitor nights, and distribution of visitor nights into each of 50 travel zones. Results A total of 515 groups consisting of 1,692 persons were contacted during the study. Thirty one percent of the permits sampled were issued for east side trailheads while the rest were for west side trailheads. Of the east side issued permits over half (79 of 155) had been mailed out in advance of the trip. The others had all been issued either the day of or one or two days before the trip at one of two centralized issuing points located in the towns of Bishop and Lone Pine, Calfornia. All of the west side permits were issued in person within 24 hours of departure. Compliance. Of the 515 groups contacted, 500, or 97.1 percent, had obtained a wilderness permit. This represents approximately 98 percent of both the persons and visitor nights accounted for by the contacted parties. The number of groups not obtaining a permit was so small (15) that the spatial and temporal effects of noncompliance on visitor use were not examined. The fifteen noncomplying groups had 38 people who contributed 159 visitor nights. These numbers were not reported on permits thus contributing to an underreporting of visitor use. The average party size of 2.5 for noncompliers compares with 3.3 persons per party for those obtaining permits. The high level of compliance as compared with that reported for other areas (Lime and Lorence 1974, Fazio and Gilbert 1974, van Wagtendonk and Benedict 1980) is attributed to the requirement for permits being in effect since 1971, successful contacts with potential visitors, and the strategic location of permit issuing stations. Transmission Errors. Although constraints on time and personnel (permits were issued periodically at nine issuing stations) did not allow for monitoring of all types of transmission errors (such as whether the information provided by the visitor was accurately recorded) we were able to evaluate permits for missing data. Only one to two percent of the permits had missing entry or exit data, entry or exit trailhead, or group size. About seven percent had missing zip codes. The first travel zone encountered was missing on 7 percent of the permits while 13 percent had the number of nights in the first travel zone missing. Changes in Visitor Plans. In evaluating the effects of

changes in visitor plans on the difference between reported and actual use we have assumed that transmission errors are relatively minor and have no systematic bias. As was discussed previously, one of the major sources of potential inaccuracy in permit data comes when permits are mailed out in advance of the trip but no means is available to monitor whether the trip is ever taken. In this study we only contacted groups that actually took their trip. We were thus unable to determine how many permits were issued for east side trailheads for trips that were never taken. The mean group size of parties contacted was 3.3 persons. Nearly 45 percent of the groups had two members. Table 1 indicates that 88.6 percent of the permits reporting group size had no difference between reported and actual. The remaining permits generally over-reported the number of people. In our sample, approximately 8 percent more people were reported to have visited the backcountry than actually did. The mean over-reporting was 0.28 persons per group (S.E. = 0.06). This implies that for every one thousand permits an over-reporting of 160 to 400 persons would be expected. East side permits (issued in advance or at centralized issuing points) accounted for 85 percent of the overreporting despite consisting of only 31 percent of the permits. The mean length of stay for the 515 groups contacted was 4.5 nights. Approximately 31 percent of the groups stayed one or two nights while 30 percent,stayed more than 5 nights. Trips originating at east side trailheads were generally longer with a mean length of stay of 5.7 nights opposed to 3.8 nights for west side trips. Total visitor nights followed a similar pattern. Table 2 presents the difference between reported and actual group length of stay based on entry and exit dates. Nearly 60 percent of the groups stayed the same number of nights that their permit indicated. Thirty six percent of the groups shortened their projected length of stay by one or more nights. Only 4.4 percent stayed longer than planned. The mean over-reporting of nights was 0.60 per group (S.E. = 0.08). Over-reporting for east side trailheads was 0.71 nights per group as compared with 0.57 for west side trailheads. Overall, the number of group nights was overreported by about 12 percent. The difference between reported and actual total visitor nights for the parties contacted with permits is presented in Table 3. While the majority of permits (55.3 percent) were in agreement for projected and actual visitor nights, almost all of those that were not (200 out of 218) over-reported. Actual visitor nights were approx-

Wilderness PermitAccuracy

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Table 1. Difference between reported and actual group size.

- 4 or less

-3

1 0.2

1 0.2

Number of permits Percent of permits a

Number of people under (-) and over (+) reported per permit -2 - 1 0 +1 2 0.4

6 1.2

437 88.6

l3 2.6

+2

+3

+4 or more

13 2.6

8 1.6

12 2.4

aAdjusted for missing values.

Table 2. Difference in reported and actual length of stay.

-6orless

-5

2 0.4

0 0

Number of permits Percent of permits a

Number of nights under (-) and over (+) reported per permit -4 -3 -2 -1 0 +1 0 0

8 1.6

1 0.2

11 2.2

295 59.6

99 20.0

+2

+3

+4

+5

+6 or more

43 8.7

14 2.8

14 2.8

1 0.2

7 1.4

+3

+4

+5

+6ormore

18 3.7

33 6.8

6 1.2

90 18.4


Table 3. Difference between reported and actual visitor nights.

-6orless Number of permits Percent of permits a

11 2.2

Number of visitor nights under ( - ) or over (+) reported per permit -5 -4 -3 -2 -1 0 +1 +2 0 0

1 0.2

2 0.4

1 0.2

3 0.6

270 55.3

13 2.7

40 8.2


imately 80 p e r c e n t o f that indicated by the permits. O n t h e average, each p e r m i t over-reported by 3.7 visitor nights (S.E. = 0.52). East side permits over-reported by 8.2 a n d west side permits by 1.8 visitor nights p e r permit. A n u n d e r s t a n d i n g o f the spatial distribution o f the d i f f e r e n c e between r e p o r t e d a n d actual visitor nights can be a n i m p o r t a n t factor in d e t e r m i n i n g acceptable use levels for specific backcountry areas. In general, we f o u n d use to be u n d e r - r e p o r t e d only for a few heavily u s e d zones. T h e s e apparently act as magnets o r sinks, taking use f r o m over-reporting zones. Many o f the overr e p o r t i n g zones are difficult to reach,, interior zones which m a n y projected trips never get to. This may result f r o m a n overestimation o f physical capabilities or simply a p r e f e r e n c e to s p e n d m o r e time than p l a n n e d in p o p u l a r o r easy to reach areas. A n u n d e r s t a n d i n g o f which areas show consistent over- o r u n d e r - r e p o r t i n g o f

use is i m p o r t a n t w h e n establishing use capacities based o n use/impact relationships.

Discussion and Conclusions Wilderness permits tend to over-report g r o u p size, l e n g t h o f stay, a n d visitor nights. T h e s e differences can be especially significant w h e n m a n a g e m e n t decisions on carrying capacities, trailhead quotas, o r work schedules are based o n r e p o r t e d use levels. It is r e c o m m e n d e d that efforts be m a d e to adjust for inaccuracies in wilderness p e r m i t data w h e n e v e r possible. Results f r o m o u r study indicate that changes in visitor plans are by far the most significant factor in overr e p o r t i n g o f backcountry use. Actual visitor nights were o v e r - r e p o r t e d by 23 percent. This was d u e primarily to a

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D.J. Parsonsand others

shortening of trip length than a reduction in group size. Such changes are hardly surprising when the variety of factors that can lead to a shortened trip are considered. Sudden weather changes, physical or health problems, loss of food to bears, or simply a tendency to over-project the length of one's trip to "be on the safe side" can all contribute to over-reporting. On the other hand, work schedules and limited food supplies seldom allow for lengthening of a trip. Correction factors to account for over-reporting as a result of changes in visitor plans can be obtained only through field or mail surveys that document changes in projected itineraries. Over-reporting of group size occurred primarily in conjunction with those permits that were mailed out in advance. This type of error, as well as transmission errors, can be minimized with close control of the permit issuing process. The practice of mailing out permits in advance contributes significant sources of error to reported use and is not recommended. This practice also poses the significant problem, which we were unable to address, of not knowing whether a permit is ever used. Furthermore, those permits never used may take away a portion of the use quota which would have been available to someone else. It is recommended that all permits, even those reserved well in advance, be filled out only once the party has arrived at the issuing station. If logistical considerations require that reservation permits continue to be mailed out, it will be necessary to develop an adjustment factor to approximate actual use patterns. Noncompliance with the requirement to obtain a wilderness permit contributes to under-reporting of use. In our study, less than three percent of the parties contacted did not have permits. These represented only 2 percent of the visitors and visitor nights. At such levels noncompliance is probably not significant enough to try to correct. However, some sampling is required in order to know what the compliance rate is and, if it reaches an unacceptable level, what correction is required. Lime and Lorence (1974) reported 88 percent compliance for the Boundary Waters Canoe Area and suggested that use figures be adjusted separately for different user types. Van Wagtendonk and Benedict (1980) have suggested a correction equation which considers both noncompliance and changes in visitor plans for use in the Yosemite backcountry. T h e redistribution of projected use between travel zones can cregte problems when use capacities or trailhead quotas have been based on reported use levels. For example, consistently under-reported zones may require such special management action as adjusted

capacities, increased patrol or special restrictions. In those cases where zone or trailhead quotas are based on reported permit data, it may be necessary to increase or decrease quotas depending on the extent and distribution of permit inaccuracies. Our results indicate that wilderness permit data have large and systematic errors. They also suggest that a portion of these errors may be controlled by carefully training permit issuers and requiring that permits be picked up in person at the start of the trip. Other error components such as changes in visitor plans also are significant, though considerably less controllable. Area specific empirical studies of all components of permit inaccuracies will be required if accurate permit data is determined to be important to management of the area. Factors such as cost and impacts on the wilderness visitor will have to be considered in deciding on the thoroughness and periodicity of such studies. It is also important to recognize that the extent of inaccuracies in permit data may vary through the year or from year to year. Such factors as who or how many persons are issuing permits (quality control), the hours that permit issuing stations are open, or changes in weather, can respectively affect transmission, compliance, and change in visitor plan errors. While it may be difficult to fully account for such variables it is important to be aware of them. The use of correction factors to adjust the accuracy of wilderness permit data should increase the ,reliability of planning and other wilderness management decisions that must be based on use reporting. The specific correction factors used can only be derived through areaspecific empirical studies.

Note Added in Proof The Inyo National Forest has announced that wilderness permits will not be mailed out in advance beginning in 1982.

Acknowledgments Valuable field assistance was provided by Steve DeBenedetti, Sue MacLeod, Rick Hedlund, David Schultz, Virginia King, and Mignonne Bivin. Jan van Wagtendonk, Bob Lucas, and Henry Vaux reviewed and made valuable comments on early drafts of the manuscript. The work was supported by the National Park Service.

Wilderness PermitAccuracy

Literature Cited Fazio, J. R., and D. L. Gilbert. 1974. Mandatory wilderness permits: Some indications ofsuccess.J. For. 72:753-756. Hendee, J. C., and R. C. Lucas. 1973. Mandatory wilderness permits: a necessary management tool.JFor. 71:206-209. Hendee, J. C., G. H. Stankey, and R. C. Lucas. 1978. Wilderness Management. USDA Forest Service Misc. Pub. 1365. 381 pp. Kantola, W. W. 1976. Opinions and preferences of visitors towards alternatives for limiting use in the backcountry of Sequoia and Kings Canyon National Parks. M.S. Theis. Univ. of Oregon, Eugene, OR. 83 pp. Lime, D. W., and R. G. Buchman. 1974. Putting wilderness permit information to work.J. For. 72:622-626. Lime, D. W., and G. A. Lorence. 1974. Improving estimates of wilderness use from mandatory travel permits. USDA For. Serv. Res. Paper NC-101, St Paul, MN. 7 pp. Nie, N., C. Hull, J. Jenkins, K. Steinbrenner, and D. Brent. 1975. Statistical Package for the Social Sciences, 2nd edition. McGraw-Hill, New York, NY. 675 pp. Parsons, D. J., T. J. Stohlgren, and P. A. Fodor. 1981. Establishing backcountry use quotas: An example from Mineral King, California. Environ. Manage. 5:335-340. Plager, A., and P. Womble. 1981. Compliance with backcountry permits in Mr. McKinley National Park.J. For. 79:155-156. van Wagtendonk, J. W. and J. M. Benedict. 1980. Wilderness permit compliance and validity.J. For. 78:388-401. V a n s , H. J., Jr. 1975. The distribution of income among wilderness uses.J. LeisureRes. 7:2937.

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