Vegetation and soil recovery in wilderness campsites closed to visitor use

Recreational use of wilderness results in impacts to vegetation and soil in trails and campsites. Traditionally, campsite impact studies have compared campsites receiving various levels of use with unused control areas. Field studies in Sequoia National Park, California, indicate that the degree of impact to vegetation and soils also varies within campsites. The central areas of campsites, where trampling is concentrated, show lower plant species diversity, differences in relative species cover, more highly compacted soils, and lower soil nutrient concentrations than do peripheral, moderately trampled, and untrampled areas within the same campsite. Three years after closure to visitor use, the central areas show less increase in mean foliar plant cover, and soils remain more highly compacted than in previously moderately trampled areas of the same sites. Changes in relative species cover over time are used to assess both resiliency to trampling and species composition recovery within campsites closed to visitor use.     

Disturbance of natural vegetation by camping: Experimental applications of low-level stress

Previously undisturbed sites in four different vegetation types were camped on for one night and for four nights. Changes in vegetation cover and vegetation height were measured after camping and one year later. Results are presented separately for different campsite zones—parts of the site where campers slept, cooked meals, and stored their packs. Just one night of camping was sufficient to cause evident impact in all four vegetation types, although the amount of impact varied significantly between zones and between vegetation types. Vegetation impact on campsites used four nights was generally less than twice as severe as impact on the sites used one night. The effects of camping on vegetation were also predicted for 12 other vegetation types on the basis of vegetational responses to experimental trampling. These results suggest that impact can almost always be minimized by confining camping to a small number of campsites instead of dispersing use across many campsites.     

Visitor impact on backcountry campsites in the Great Smoky Mountains

Over the last decade the Great Smoky Mountains National Park (GSMNP) has experienced a tremendous increase in visitation, especially in backcountry camping. In 1976 there were an estimated 117,500 backcountry visitor nights, with a peak of 16,865 visitor nights in April. The high use season extends from March to October. Visitation tends to be concentrated in certain sections of the park and at specific sites. The Appalachian Trail, which includes about 8 percent of the maintained trail mileage, carried 32 percent of the visitor nights in 1976.Campsite disturbance is also concentrated in specific sites and sections of the park. Maximum camping disturbance per km of maintained trail was 3,400 m² for the sites on the Appalachian Trail. Shelter sites have more visitation per site and more total disturbance per site than open campsites, but shelters tend to have less intensive disturbance, such as bare soil, because they concentrate trampling impacts. Visitation levels were strongly correlated with disturbances such as bare soil at open campsites. Visitation was significantly correlated to the number of firepits at shelter sites but not to other types of disturbance. Regressions indicate that for each additional visitor night at a site (annual average), one can expect an additional 9 m² of total disturbance and 1 m²of bare soil. The distance of a site from the nearest road was not significantly correlated with damage or visitation. Elevation was correlated to visitation levels, especially in the case of the shelters. More legal sites and large illegal sites are in mesic forest types. Illegal camping accounted for 10 percent of the total camping disturbance.The data imply that the suggested removal of shelters will require redistribution of visitor use or replacement developments, such as tent platforms, in order to mitigate damage. Zone camping is a possible alternative but presents difficulties because campers may concentrate in certain plant communities and topographic positions.     

EFFECTS OF SIMULATED CANOPY COVER AND ANIMAL DISTURBANCES ON RILL AND INTERRILL EROSION1

ABSTRACT: A rainfall simulator was used on runoff plots to study the effects of simulated canopy cover, trampling disturbance, and soil type on nil and interrill erosion. Sandy loam soil was more erodible than clay loam soil. Furthermore, the simulated canopy cover signffi-Soilfactorsrelatedtonil cantly influenced nil and interrill erosion. The effect of trampling on rill and interrill erosion varied with soil type (clay loam versus sandy loam) and erosion type (nh versus interrill erosion). On large plots, where both nil and internill erosion were involved, 30 percent trampling significantly increased soil loss. However, on small plots, 30 percent trampling significantly reduced interrill erosion.     

Campsite impact on three western Wilderness areas

Campsites were studied in subalpine forests in the Eagle Cap Wilderness in Oregon, and in the Mission Mountains Tribal Wilderness and the Rattlesnake Wilderness in Montana. Research objectives were to examine ecological changes on these sites and the extent to which these changes become more pronounced as use increases For most parameters measured, impact on campsites used for only a few nights per year exceeds threshold values beyond which further increases in use have little effect Loss of litter, tree root exposure, and site enlargement are the major types of alteration that are more pronounced on sites occupied more frequently than several nights per year In heavily used parts of backcountry areas, this suggests that ecological change can be minimized by limiting use to a small number of sites In the three areas studied, campsite occupancy rates would probably have to be no higher than a few nights per year before dispersal of use among a large number of sites would be an ecologically sound strategy     

Effects of Fireplace Use on Forest Vegetation and Amount of Woody Debris in Suburban Forests in Northwestern Switzerland

Urban forests are popular recreation areas in Europe. Several of these temperate broad-leaved forests also have a high conservation value due to sustainable management over many centuries. Recreational activities, particularly the use of fireplaces, can cause extensive damage to soil, ground vegetation, shrubs, and trees. Firewood collection depletes woody debris, leading to a loss of habitat for specialized organisms. We examined the effects of fireplace use on forest vegetation and the amount of woody debris by comparing disturbed and control plots in suburban forests in northwestern Switzerland. At frequently used fireplaces, we found reduced species densities in the ground vegetation and shrub layer and changes in plant species composition due to human trampling within an area of 150–200 m². Picnicking and grilling also reduced the height and changed the age structure of shrubs and young trees. The amount of woody debris was lower in disturbed plots than in control plots. Pieces of wood with a diameter of 0.6–7.6 cm were preferentially collected by fireplace users. The reduction in woody debris volume extended up to a distance of 16 m from the fire ring, covering an area of 800 m² at each picnic site. In order to preserve the ecological integrity of urban forests and to maintain their attractiveness as important recreation areas, we suggest depositing logging residues to be used as firewood and to restrict visitor movements near picnic sites.     

A classification of backcountry campsites in Prince William Sound,Alaska, USA

This study examined resource conditions on backcountry campsites in Prince William Sound, Alaska, USA. In order to further the understanding of campsite impacts and to improve monitoring and assessment methods, we employed a multivariate analysis procedure, suggested in one study, but heretofore untested on data from other campsite assessments. Factor analysis of ten impact indicator variables from 146 campsites produced three dimensions of campsite impact—tree and vegetation disturbance, areal disturbance and visitor behavior-related disturbance. Three types of campsites, which differed substantially in the types of impact exhibited, were then derived from a cluster analysis of the factor scores. Further analysis revealed a significant relationship between the types of substrates where campsites were located and the types of campsites derived from the analysis. This work illustrates the utility of multi-indicator monitoring approaches and the use of multivariate methods for classifying campsites, as the campsite types identified would likely require different management strategies for limiting the proliferation and expansion of impacts.     

The localized environmental degradation of protected areas adjacent to bird feeding stations: a case study of the Australian brush-turkey Alectura lathami

This study investigated the potential for wildlife feeding to artificially increase population densities of the Australian brush-turkey, Alectura lathami and assessed the indirect adverse effects that this may have on surrounding forest floor vegetation. Census counts and observations of feeding activity conducted in recreation areas of Australia's Gold Coast hinterland confirmed that brush-turkey population densities were significantly elevated by the provision of food by humans. Brush-turkey densities were high at sites where birds are actively fed, moderate at sites where birds feed opportunistically and low at sites where humans have negligible impact on local food availability. Brush-turkeys caused significant environmental impact at sites where their population densities have been substantially elevated by active feeding. Across all sites, increases in brush-turkey density were accompanied by a significant decline in ground cover, leaf litter weight, seed density and seedling density. Natural environmental variables such as gradient, vegetation type and canopy cover did not explain the observed impacts. The impacts were consistent with those described in trampling studies and suggest that at high density, even small animals can have significant trampling impacts on their local environment. This study demonstrates that wildlife feeding can have detrimental impacts on the integrity of local environments and recommends greater consideration of small animals and their potential indirect impacts when regulating wildlife feeding in National Parks and other nature conservation areas.     

Sociological edge effects: Spatial distribution of human impact in suburban forest fragments

Suburban forest fragments often experience heavy recreational and waste disposal use, with considerable damage to the vegetation. To suggest strategies for conservation of the forest flora, spatial distributions of human impact were described in 40 fragmentary stands in northern New Castle County, Delaware. The distribution of human impact showed a significant bias to the forest edge, with 95% of localized damage occurring in the first 82 m. Forms of impact related to lawn maintenance fell significantly closer to the edge than impacts related to recreation and showed the strongest edge orientation. Edge distances of campsites, vandalized trees, and firewood gathering were negatively correlated with distance to the nearest graded road, indicating the importance of road access. Several forms of impact were also clustered near footpaths, although distance to paths was independent of edge distance in all cases. In terms of penetration of the forest and severity of damage, human impact greatly exceeds natural edge effects reported for this community. These findings suggest that damage may be minimized by limiting road access and avoiding the creation of small forest fragments.     

Trampling Impacts on Thermotolerant Vegetation of Geothermal Areas in New Zealand

Geothermal features such as geysers, mud pools, sinter terraces, fumaroles, hot springs, and steaming ground are natural attractions often visited by tourists. Visitation rates for such areas in the Taupo Volcanic Zone of New Zealand are in the order of hundreds of thousands annually. These areas are also habitat for rare and specialized plant and microbial communities that live in the steam-heated soils of unusual chemical composition. We evaluated historical and current trampling impacts of tourists on the thermotolerant vegetation of the Waimangu and Waiotapu geothermal areas near Rotorua, and compared the results to experimental trampling at a third site (Taheke) not used by tourists. Historical tourism has removed vegetation and soil from around key features, and remaining subsoil is compacted into an impervious pavement on which vegetation recolonization is unlikely in the short term. Social tracks made by tourists were present at both tourist sites often leading them onto hotter soils than constructed tracks. Vegetation height and cover were lower on and adjacent to social tracks than further from them. Thermotolerant vegetation showed extremely low resistance to experimental trampling. This confirms and extends previous research that also shows that thallophytes and woody shrubs, life forms that dominate in thermotolerant vegetation, are vulnerable to trampling damage. Preservation of these vulnerable ecosystems must ensure that tourist traffic is confined to existing tracks or boardwalks, and active restoration of impacted sites may be warranted.     

Effects of recreational use on forested sites

Impact of recreational activities on soil and vegetation was evaluated in eight forested camping and picnic areas in southern Rhode Island. Forest vegetation consists of mixed-oak and white pine stands. Soils are of granitic glacial till or outwash origin and textures range from loamy sand to find sandy loam. Recreational use resulted in significant compaction of soils as indexed by soil penetration resistance and bulk density. Evidence indicates that compaction influences bulk densities to a depth of about 12.7 cm. Rates of water infiltration are less on recreation areas. Soil water accretion and depletion during the growing season are less rapid on recreation sites than on control sites. Differences are attributed to reduced infiltration, percolation, and rooting activity. Much of the ground surface on recreation areas is devoid of vegetation. The surface consists primarily of bare mineral soil, rock, or litter. The plants most commonly present are grasses. Native ground cover vegetation including tree seedlings, ericaceous shrubs and herbs has been eliminated or greatly reduced by trampling. Damage to tree trunks is common in recreation areas. White pine radial growth and scarlet oak height growth were significantly less on recreation sites. Scarlet oak appears intolerant to heavy recreation use.     

The response of two arctic tundra plant communities to human trampling disturbance

A 4-year study was conducted to evaluate the consequences of human trampling on dryas and tussock tundra plant communities. Treatments of 25, 75, 200 and 500 trampling passes were applied in 0.75 m2 vegetation plots at a time of approximately peak seasonal biomass. Immediately after and 1 and 4 years after trampling, plots were evaluated on the basis of plant species cover, percent bare ground, vegetation height, and soil penetration resistance. One year after trampling, soils were collected for nitrogen analysis in highly disturbed and control plots. Immediately after trampling, 500 trampling passes resulted in approximately 50% cover loss in the dryas tundra and 70% cover loss in tussock tundra, but both communities showed a substantial capacity for regrowth. Plots where low and moderate levels of trampling were applied returned to pre-disturbance conditions by 4 years after trampling, but impact was still evident in plots subjected to high levels of disturbance. These results suggest that these tundra communities can tolerate moderate levels of hiking and camping provided that use is maintained below disturbance thresholds and that visitors employ appropriate minimum-impact techniques. By utilizing this information in a visitor education program combined with impact monitoring and management, it is possible to allow dispersed camping and still maintain these vegetation communities with a minimum of observable impact.     

Twenty Years of Change on Campsites in the Backcountry of Grand Canyon National Park

This article draws on three separate research and monitoring studies to describe 20-year trends in the number and condition of campsites in the backcountry of Grand Canyon National Park. Results are used to assess the effectiveness of a complex and innovative management program, adopted in 1983, that sought to concentrate use on designated campsites in popular places and disperse camping in more remote places. In 1984, conditions on 12 high-use campsites and 12 low-use campsites were carefully assessed. Conditions on 22 of these campsites were reassessed in 2005. In addition, campsite-monitoring surveys were conducted between 1985 and 1992 and again in 2003 and 2004. In these surveys, all campsites were located and their condition rapidly assessed. The detailed assessment of a sample of sites suggests relatively little change in condition during the 20-year period. The high-use sites were more highly disturbed than the low-use sites, but they did not change more during the study period. In contrast, changes at larger scales were dramatic. The total number of campsites more than doubled during the study period. Surprisingly, the proliferation of new campsites was greater in places where camping was only allowed on designated campsites than in places where camping was allowed anywhere. Concern that concentration of use on designated sites would cause unacceptable impact was unfounded. Management implications for other internationally significant protected areas that allow backcountry camping are explored.     

Impacts of experimental trampling on tall alpine herbfields and subalpine grasslands in the Australian Alps

The Australian Alps, which are of high conservation value, are popular summer bushwalking destinations. Experimental trampling trials using a standardized methodology were conducted to determine the resistance and resilience of the two common vegetation types: tall alpine herbfield and subalpine grasslands. Vegetation parameters were measured in lanes subject to control (no trampling), 30, 100, 200, 500 and 700 passes at five sites prior to trampling, immediately post trampling, 2 weeks, 6 weeks and 1 year post trampling. Vegetation height, cover of graminoids and herbs, as well as net species richness all declined with trampling, while litter cover increased. Thresholds for damage varied between the two communities and among the different vegetation parameters. The resistance indices for the two communities (number of passes resulting in 50% reduction in vegetation cover), however, were similar at around 440–450 passes indicating that these two communities are among the most resistant of the 19 alpine–subalpine communities that have been tested around the world, but only of moderate resistance compared to non-alpine communities. The two communities showed limited recovery with damage still evident 1 year post trampling. This indicates that they have only moderate tolerance to damage due to moderate resistance, but low resilience.     

Models to Assess the Risk of Snow and Wind Damage in Pine, Spruce, and Birch Forests in Sweden

3 are damaged annually by snow and wind, roughly corresponding to a value of US$150 million, and in Europe, the damage amounts to hundreds of millions of US dollars each year. To help to reduce these losses, tools for risk assessment within forest management have been developed. Predictions were developed of the risk of damage from snow and wind to Scots pine (Pinus sylvestris L.), Norway spruce [Picea abies (L.) Karst.] and Birch (Betula spp. L.) plots using tree, stand, and site characteristics. The data were obtained from 6756 permanent sample plots within the Swedish National Forest Inventory, which were inventoried twice at five-year intervals between 1983 and 1992. Input data for model development used measurements from the first inventory of tree characteristics for the largest sample tree, stand, and site data, and records of snow and wind damage from the second inventory. Models were developed for three different regions for pine- and spruce-dominated sites, while models for the whole country were developed for birch sites. In general the estimated proportion of damaged plots was highly overestimated (31.7%–56.2%), compared with the observed proportion of 3.4%–11.9%. The models for Norway spruce comprising tree, stand, and site data show the best predictability of damaged plots, with 60.6%–67.6% of plots correctly classified. It is concluded that the models developed can be used to detect sites with a high probability of damage from snow and wind, and thus be used as tools to reduce future damage and costs in practical forestry.     

The impact of human frequentation on coastal vegetation in a biosphere reserve

We aimed to assess the impacts of recreational trampling on rare species, plant communities and landscape structure in the Iroise Biosphere Reserve (western France). Focusing on coastal grasslands, we first identified indicators discriminating human-induced short grasslands (i.e. maintained short by intensive trampling) from natural short grasslands (i.e. maintained by environmental constraints): the presence of lichens and succulent or woody species, which are known to be highly sensitive to trampling, as well as a shallow soil were good indicators of natural short grasslands. Recreational activities affected the majority of plots containing rare species, but one third of rare species (according to their habitat preference) appeared currently not threatened by recreational activities. The other rare species were found in grasslands with low trampling intensity and were not found in grasslands with greater trampling intensity. One lichen species (Teloshistes flavicans) was not affected by trampling intensity, while two plants species (Scilla verna and Ophioglossum lusitanicum) showed higher abundances when trampling was low to medium. When it occurs in natural short grasslands, tourist trampling reduced drastically plant species richness. However, when considering maritime high grasslands, we observed that species richness was higher under low trampling vs. no trampling, but decreased at higher trampling intensity. At a landscape scale, the mean annual rate of path creation was about 1.6% and tourist trampling has already completely destroyed 3.5ha of natural coastal vegetation. Trampling of maritime-high grassland has also created 31ha of short grasslands, which represent 50.8% of the whole short grassland habitat of the island. Moreover trampling affected respectively, 41% and 15% of natural short grasslands and maritime-high grasslands. One of the main suggestions for managers to minimise trampling impacts should be to protect areas of rocky soil covered by short grassland that are still non-trampled and not impacted. Fortunately, this appears compatible with a relatively free access of visitors to coastal areas, as tourists can be redirected towards maritime-high grasslands, an habitat which is less impacted by tourism in terms of affected surface, soil cover, loss of species, or presence of rare species host.     

Scale-dependent inconsistencies in the effects of trampling on a forest understory community

The response of forest understory vegetation to trampling applied at different temporal and spatial scales was determined in a cliff-edge forest in Ontario, Canada. Three frequencies (0, 50, 500 passes per year) of short-term trampling (one year) were applied to plots previously undisturbed. Existing trails that had received three frequencies (approx. 100, 500, 25,000 passes per year) of long-term trampling (18 years) were also studied. Community composition, species richness, and individual species frequency were recorded in plots within 4 m and (or) 1 m of the patch centerline. The quantitative and qualitative form of plant response to increased trampling was compared for short-term and long-term treatments, both within 4 m and within 1 m of the path centerline, to judge the consistency of trampling effects at different temporal and spatial scales. As trampling frequency increased, community composition changed progressively, but consistently, in plots both within 4 m and 1 m of the path centerline. Species richness was less affected by trampling and only decreased within 1 m of the path centerline at the highest level of trampling (25,000 passes per season for 18 years). Effects of trampling on individual species frequency were much less consistent at different temporal and spatial scales of trampling. The scale-dependence results suggest that field workers and resource managers both should try explicitly to include and define multiple scale components when trying to ascertain the response of vegetation to human disturbance factors.     

A Comparison of Campfire Impacts and Policies in Seven Protected Areas

Using resource-monitoring data from seven protected areas, the effectiveness of three campfire policies—campfire ban, designated campfires, and unregulated campfires—were assessed based on the number of fire sites and the amount of tree damage. Results indicate that unregulated campfire policies permitted substantial numbers of fire sites and tree damage in campsites, although fire bans did not eliminate or even substantially decrease these problems. A designated campfire policy was effective in decreasing number of fire sites, but little difference was found among policies regarding tree damage. Given the importance of campfires to visitor experiences, campfire prohibitions could be viewed as unnecessarily restrictive based on their limited success in preventing resource damage. Conclusions encourage protected-area managers to consider designated campfire policies and prohibitions on axes, hatchets, and saws to better meet resource protection and visitor experience mandates.     

Simplification of Pine Forests Due to Utilization by Tibetan Villages in Southwest China

In China, many rural communities depend upon forests to provide wood, fuel, fertilizer, animal bedding, and valuable non-timber forest products (NTFP). However, the degree to which forest resource extraction is compatible with new conservation aims is unclear because there is little information on the specific ecological effects of traditional forest collecting practices. Therefore, we compared the structure and floristics of Pinus densata forests exposed to three levels of resource extraction by Tibetan villages in northwest Yunnan: (1) a forest site protected from wood and timber removal, (2) moderately utilized forest sites exposed to traditional collecting practices, and (3) patches of highly utilized forest from which timber extraction is high in response to recent development pressures. The results show that understorey and cryptogamic species are reduced in all the utilized forest sites by comparison with the protected forest. However, the moderately utilized pine forests still provide good NTFP habitats by maintaining relatively high canopy covers, litter covers, and understorey structural complexity; this suggests that traditional forest resource use, while simplifying the forest, does not pose an increasing threat to pine forest integrity. By comparison, the highly utilized forests are transformed into open, herb-rich environments in which canopy covers and understorey complexity are depleted, and NTFP habitats are degraded. In the future it may be practical to enhance biodiversity by proscribing forest resource collection, but the immediate priority is to monitor the sustainability of forest utilization using indicators such as understorey development, litter cover, and cryptogamic richness.     

Heathland Seedbanks under BrackenPteridium aquilinum(L.) Kuhn and their Importance for Re-vegetation after Bracken Control

In Great Britain, the regeneration of heathland and moorland plant communities after bracken control is slow and variable. Successful restoration depends on the availability of seed and the provision of suitable regeneration niches, as well as on the expansion of the plants previously present underneath the bracken canopy. This study investigates the availability of the seed resource of heathland species and its distribution, both in relation to increasing time since bracken invasion and with respect to its presence in litter or mineral soil.Calluna vulgariswas found to be the predominant species that germinated from the soil and litter beneath bracken at the sites studied. It appeared in greatest numbers from samples taken outside and at the edge of the bracken patch; numbers decreased deeper into the patch. Land which has been under bracken for a considerable period (>50 years) is likely to have a very reduced seedbank so that some form of propagule introduction, as well as litter disturbance, may be needed to speed up regeneration. On sites which have been invaded by bracken more recently, it is likely that litter incorporation into the soil would conserve the seed resource, whereas burning or litter removal would remove a significant proportion of that seed resource.