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A Review and Synthesis of RecreationEcology Research Findings on Visitor Impactsto Wilderness and Protected Natural AreasJeffrey L. Marion, Yu-Fai Leung, Holly Eagleston, andKaitlin Burroughs

The 50th anniversary of the US Wilderness Act of 1964 presents a worthy opportunity to review our collectiveknowledge on how recreation visitation affects wilderness and protected natural area resources. Studies ofrecreation impacts, examined within the recreation ecology field of study, have spanned 80 years and generatedmore than 1,200 citations. This article examines the recreation ecology literature most relevant to wildernessand backcountry, with a focus on visitor impacts to vegetation, soil, wildlife, and water resources. We also reviewrelationships with influential factors, such as the amount of use, visitor behavior, and vegetation type. Anunderstanding of these impacts and their relationships with influential factors is necessary for land managersseeking to identify acceptable limits of impact or selecting management actions that will effectively avoid orminimize resource impacts.

Keywords: recreation ecology, visitor impacts, wilderness recreation

S ince passage of the 1964 WildernessAct, the US National WildernessPreservation System (NWPS) has

grown from 54 units and 9 million acres to758 units and nearly 110 million acres.1 TheNWPS currently represents about 5% of theentire United States, an area slightly largerthan the state of California. Four federalland management agencies are responsiblefor the stewardship of these protected lands:the National Park Service (�44 millionacres), the Forest Service (�36 millionacres), the Fish and Wildlife Service (�21million acres), and the Bureau of Land Man-agement (�9 million acres). The profes-sional stewardship of these lands to maintaintheir wilderness character, defined in part as

undeveloped lands retained in their naturalcondition and unhindered by human ac-tions, requires objective information aboutinternal and external threats (Landres et al.2011). Recreational visitation, while recog-nized in the Wilderness Act as a core tradi-tional use of wilderness, is also a principalinternal threat to wilderness preservation.

This article provides a review and syn-thesis of the environmental impacts associ-ated with recreational visitation of wilder-ness and other protected natural areas, alongwith a discussion of influential factors affect-ing the nature and severity of these impacts.The term impact in this article denotes anyundesirable visitor-related biophysical changeto natural resources. Such knowledge pro-

vides an essential basis for deliberations anddecisions regarding the acceptability of visitorimpacts and the selection of effective manage-ment actions designed to avoid or minimizeresource impacts. The field of study thatgenerates this knowledge is known as recre-ation ecology, which has been defined as thescientific study of ecological changes associ-ated with visitor activities, including the roleof influential factors (Leung et al. 2008,Monz et al. 2010a). This review is derivedprincipally from studies conducted in desig-nated wilderness areas and comparable wild-land and backcountry settings in the UnitedStates, collectively referred to as protectednatural areas. Studies from other countriesare also included if they are directly relevantto specific impact topics. Additional discus-sion on this subject matter is available fromLiddle (1997), Newsome et al. (2012), andHammitt et al. (2015).

Recreation visitation to protected naturalareas inevitably degrades natural resourcesintended for protection, creating tensionbetween recreation provision and resourceprotection goals and mandates. Vegetationis trampled, soil is eroded, water quality isaltered, and wildlife are disturbed. Theseimpacts occur primarily in locations that re-

Received June 2, 2015; accepted January 27, 2016; published online March 22, 2016.

Affiliations: Jeffrey L. Marion ([email protected]), US Geological Survey, Virginia Tech, Blacksburg, VA. Yu-Fai Leung ([email protected]), North Carolina StateUniversity. Holly Eagleston ([email protected]), Virginia Tech. Kaitlin Burroughs ([email protected]), North Carolina State University.

Acknowledgments: We thank Dr. Susan Fox for her support and the anonymous reviewers who have provided constructive feedback.

REVIEW ARTICLE

352 Journal of Forestry • May 2016

J. For. 114(3):352–362http://dx.doi.org/10.5849/jof.15-498

ceive substantial visitation. A primary goalof protected area and wilderness manage-ment is to limit the areal extent of visitorimpacts, the human “footprint” of highlydisturbed land. Of equal importance is lim-iting the severity of impact to levels that arenot ecologically, managerially, esthetically,or functionally significant. The professionalmanagement of visitor impacts to protectednatural areas requires a thorough under-standing of the various types of impacts,their severity, extent, and spatial distribu-tion, and the influence of factors, some ofwhich are causal factors such as the amountof use and visitor behavior, and others arenoncausal factors such as environmental sus-ceptibility. This review focuses on recreationimpacts to vegetation, soil, water, and wild-life, including the role of key influential fac-tors. Most of these impacts occur on or nearrecreation sites (e.g., campsites, picnic sites,boat launches, and vista points) and trailcorridors. The accompanying article byMarion (2016) focuses on describing themost effective visitor impact managementstrategies and tactics derived from recreationecology science and management experi-ence.

Synthesis of Research

Vegetation Impacts—Light TrafficVisitor trampling associated with recre-

ational activities results in a variety of im-pacts to vegetation, including a reductionin vegetation cover, height, and biomass,changes in species composition, and the in-troduction and spread of nonnative plants(Figure 1). Plant resistance is the intrinsiccapacity of vegetation to withstand the di-rect effect of trampling by feet, hooves, andtires (Liddle 1997). Under light recreationaltraffic, most plants respond with a reductionin plant height. Even light trampling willbreak rigid stems, which can halt flower andseed development and reduce plant vigor(Cole 1987, Barros and Pickering 2015).

A meta-analysis of trampling studies byPescott and Stewart (2014) found that plantmorphological characteristics strongly influ-ence the response of vegetation to tramplingdisturbance. For example, the brittle woodystems of shrubs and small trees and rigidstems of tall forbs (herbs) are susceptible totrampling damage, and their breakage elim-inates the growing tips (perennating buds),flowers, and seed production (Cole 1995b,Cole and Monz 2002). In contrast, grassesand sedges (graminoids) with turf or tuft

growth forms and low-growing herbs hadsubstantially greater trampling resistancedue to their flexible stems and leaves andperennating buds at or below the groundsurface (Hill and Pickering 2009, Striker etal. 2011). In an experimental tramplingstudy on an alpine grass and sedge turf, 500passes by a hiker reduced cover 40%,whereas the same level of trampling in a sub-alpine forest with a forb and fern understoryreduced cover 97% (Cole 1995a).

Studies show that these differences inmorphology and trampling resistance arehighly correlated with sunlight intensity(Liddle 1997, Cole and Monz 2003). Non-woody shade-tolerant plants require largeleaf surfaces supported by strong rigid stemsthat are easily crushed. In contrast, sun-lov-ing plants (particularly graminoids) can ob-

tain the necessary sunlight with small or nar-row leaves and flexible stems. In a study ofdesignated campsites in the Boundary Wa-ters Canoe Area Wilderness (BWCAW),Marion (1984) found that the amount ofsunlight was the most influential predictorof vegetation cover, ranging from an averageof 4% cover on shady campsites (�75% treecover) to 52% cover on sunny campsites(�25% tree cover).

Plant resilience, the capacity of vegeta-tion to recover from trampling damage, isanother important plant characteristic toconsider (Liddle 1997). Similar to plant re-sistance under conditions of light traffic,woody plants and tall herbs with rigid stemsare least resilient because all perennatingbuds are lost when stems are broken orcrushed. Broken woody branches can re-

Management and Policy Implications

Outdoor recreation in wilderness and other protected natural areas is an important value and ecosystemservice to our society, but visitor activities can also induce undesirable effects to various ecologicalcomponents and visitor experience. To integrate wilderness protection and recreation objectives, managersrequire objective information on recreation impacts so they can evaluate the ecological and socialsignificance of impacts as well as their control. This article synthesized recreation ecology research intendedfor enhancing our understanding of recreation impacts while advancing the practice of visitor impactmanagement. The results suggest that advances in recreation ecology have gone further with vegetationand soil, whereas research on wildlife impacts has gained momentum in recent years. Recreation impactson water quality remains a less active research area. The body of knowledge on recreation impacts hasdemonstrated its utility in informing visitor planning, management and education strategies, and actionsbeing implemented in wilderness and other protected natural areas.

Figure 1. Diagram of vegetation and soil impacts resulting from human trampling.

Journal of Forestry • May 2016 353

quire years to recover, and tall herbs are of-ten unable to recover sufficiently to flowerwithin the growing season. Thus, woodyplants and tall herbs generally have low re-silience (Cole 1995b), and their rates of ger-mination and survival under trampling pres-sure are quite low (Marion and Cole 1996).Numerous studies have documented thesubstantially greater resilience of graminoidsas a group, attributed primarily to stem flex-ibility, leaf durability, and fast growth rates(Sun and Liddle 1993, Pickering 2010).Plant resilience is also highly dependent onenvironmental attributes: plant recovery isgenerally higher in locations with greatersunlight, soil fertility, moisture, and longgrowing seasons (Marion and Cole 1996,Hartley 1999, Pescott and Stewart 2014).

Vegetation Impacts—Moderate/HighTraffic

As recreational activity increases be-yond initial and low levels of traffic, plantcover and biomass are reduced as planthealth and vigor are degraded (Figure 1).Damage and removal of leaves rendersplants unable to produce sugars and storecarbohydrates in roots, which slows or haltsflowering and seed production and reducesplant growth in subsequent years (Liddle1997, Hartley 1999). Plants that are sensi-tive to trampling are greatly reduced in sizeand cover or are removed by moderate levelsof trampling, whereas more resistant speciesmay even increase their number and cover(Cole and Monz 2003, Cole 2013). Suchcompositional changes in vegetation occurslowly over many years, but the cumulativelong-term effects can be substantial, e.g.,forest herbs are replaced by grasses, low-growing herbs, and sometimes mosses (Mar-ion 1984, Mortenson 1989, Liddle 1997).Over time, additional compositional changes of-ten occur from the introduction and disper-sal of nonnative plants, which may out-com-pete and replace native species (Underwoodet al. 2004, Dickens et al. 2005, Pickeringand Hill 2007). Fortunately, the majority ofnonnative plants are disturbance associatedand shade intolerant; however, a few cannaturalize and become invasive, outcompet-ing native plants in undisturbed settings(Marion et al. 1986). These are the “high-priority” invasive species that land managersgenerally target for removal. Additional re-search is needed to determine the potentialthreats posed by introduction of nonnativeplants along informal (visitor-created) trailsor from new activities such as geocaching.

Higher levels of trampling, includingintensive traffic at the center of campsitesand trails, generally remove all plant cover(Figures 1 and 2) (Monz et al. 2010b). Themost trampling-resistant species often sur-vive only in slightly less trafficked peripheralareas, such as near trail and campsite bor-ders. As previously noted, other factors, suchas the amount of sunlight and soil nutrientsor moisture, are also important determi-nants of vegetation survival. For example,trails and campsites in meadows can retainsubstantially greater plant groundcover thanthose in adjacent woods (Marion and Cole1996). Long-term impacts from tree damageand felling, tree root exposure, and loss oftree regeneration can result in a reductionand loss of the forest canopy. Invasive spe-cies introduced to trails and campsites canspread to adjacent areas through self-propa-gation over time (Pickering and Hill 2007).

As described in the preceding discus-sion, herbaceous vegetation in forests isquickly lost under even relatively low levelsof traffic. When the majority of vegetationcover is lost, further recreational traffic oruse causes little additional impact to vegeta-tion if visitors stay on well-established trailsand recreation sites. Traffic can double ortriple with limited increases in vegetationimpact, a finding that has been illustrated ina large number of studies (Cole 1995a,Leung and Marion 2000, Monz et al. 2013).This curvilinear use-impact relationship isillustrated in Figure 3, where 70% of thevegetation loss occurring on high-use BW-CAW campsites (�60 nights/year) has al-ready occurred on sites receiving just 10nights of camping/year (Marion 1984).

The use-impact relationship is some-what different for the more resistant and re-silient graminoids. Grasses and sedges canwithstand prolonged low levels of traffic,particularly in sunny locations. For example,Cole and Monz (2003) found that after fournights of camping, meadow sites recoveredcompletely after 1 year, whereas forestedsites incurred impacts after just one night ofuse and did not fully recover after 3 years.However, moderate to high levels of trafficwill reduce and remove graminoid cover sosoil is still exposed in high-traffic areas.

Impacts to SoilInitial and low levels of trampling gen-

erally affect only vegetation and organic lit-ter, such as dead plant leaves, grass, needles,and twigs. Initial trampling flattens and be-gins to degrade organic litter. Increased lev-

els of trampling cause organic litter to bepulverized, which accelerates removal bywind or water or decomposition into the un-derlying organic soil (Figure 1). Organicsoils are then exposed to traffic, but their lowdensity and lack of structure allows rapiddisplacement and loss, particularly due toerosion in sloping terrain. Organic soils inflatter terrain absorb water and becomemucky, particularly in low areas along trails.On recreation sites the loss of organic soilover time can expose large areas of underly-ing mineral soil, increasing soil temperaturesand decreasing soil moisture. The loss of in-sulating organic litter and soil also reducessoil temperatures during the winter, partic-ularly under compacted snow along snow-mobile and cross-country ski trails, causingsnowpack to remain frozen longer and im-pacting underlying vegetation and soil(Wanek 1971, Eagleston and Rubin 2013).

Recreation trampling quickly compactsexposed mineral soil (Figure 1). The groundpressure of nonmotorized recreational trafficranges from approximately 4.12 pounds persquare inch for hikers and 4.98 pounds persquare inch for mountain bikers (Thurstonand Reader 2001) to 62.3 pounds per squareinch for a shod horse and rider (Liddle1997). These mechanical forces cause soilparticles to rearrange and pack togethermore tightly, increasing soil density and de-creasing pore space. The degree of compac-tion is a function of the type and amount ofrecreational traffic (Lei 2004, Pickering et al.2010) and several physical factors. Soils witha wide distribution of particle sizes are morecompactable than those with equal-sizedparticles (Liddle 1997, Lei 2004). Soil com-paction is limited by higher moisture levelsand/or higher organic content (Marion andMerriam 1985a, Liddle 1997) but can occurrapidly with limited traffic once organic ma-terials are substantially lost. For example, onBWCAW campsites, 97% of the soil com-paction assessed on high-use sites (�60nights/year) had already occurred at moder-ate-use levels (20–40 nights/year) (Marionand Merriam 1985b) (Figure 3).

Compacted soils on recreation sites cre-ate a smooth hard surface that impedes seedgermination and penetration by plant roots(Alessa and Earnhart 2000). Soil macropo-rosity is reduced when soils are compacted,limiting air and water permeability and con-tributing to reductions in soil biota (Liddle1997). Developed campsites can experienceup to a 20-fold reduction in water infiltra-tion rates (James et al. 1979), resulting in


less water available to plants, which may ex-perience higher mortality during droughts(Marion and Merriam 1985b). Compactedsoils on flat recreation sites cause water topool, contributing to muddiness. Compac-tion of trail substrates helps deter soil dis-placement, but reduced water infiltrationrates contribute to trail muddiness in areaswith poor drainage, causing trail wideningand the creation of secondary trails whentrail users seek to circumvent muddy areas(Figure 4) (Leung and Marion 1999a, Wim-pey and Marion 2010).

Soil erosion and loss, especially water-based erosion problems, are perhaps themost significant long-term recreation im-pacts and have received attention fromrecreation ecologists (Figure 1) (Olive andMarion 2009). Soil loss from wind can occurwhen trail or recreation site substrates are

dry and loose and lack protective vegetationor litter cover. Soil erosion from water flow ismore common, particularly in sloping ter-rain and in regions with intermediate to highrainfall. Soil erosion is also governed by soilproperties, primarily soil texture (particlesize), but also organic matter content, struc-ture, and permeability. For example, lesserodible soils can be fine-textured clayeysoils whose particles aggregate and resist de-tachment or coarse-textured sandy soils,which are highly permeable and have largerparticle sizes that resist transport. Medium-textured soils with silt and fine sand are mostsusceptible to erosion; their fine particles areeasily transported by water or wind, are lesspermeable, and lack stable aggregates.

Trails in sloping terrain can interceptand channel water runoff, which can quicklyerode trail substrates in areas lacking a suffi-

cient density of effective tread drainage fea-tures. When erosion occurs on sloping trails,rocks and roots are exposed, causing hikersto walk around them and widening trails justas mud and water do in flatter terrains. Oliveand Marion (2009) found that trail position,trail slope alignment angle, trail grade, typeof use, and the proximity of water drainagefeatures were the most significant determi-nants of soil loss from trails. Steep fall-aligned trails (aligned perpendicular to con-tour lines) are particularly susceptible toerosion due to the difficulty of diverting wa-ter from their treads (Leung and Marion1996). Trail grade is a commonly cited fac-tor influencing soil loss, particularly whengrades exceed 10% and substrates lack nativerock, applied gravel, or stonework (Farrelland Marion 2002, Nepal 2003).

Amount of use can be a significant fac-

Figure 2. Although meadow grasses are more resistant and resilient to traffic than forest herbs, they are eliminated under heavy traffic.Trail management actions, such as adding woody debris, rocks, and transplanted vegetation (pictured) can help confine traffic to theintended tread.


tor at the low end of the use spectrum, butother factors cited above and the intensity oftread management are more influential athigher use levels (Farrell and Marion 2002,Nepal and Way 2007). For example, Delucaet al. (1998) found that sediment yield froma trail after 1,000 passes was significantlyhigher than after 250 passes (both are at thelow-use end of the trail use spectrum). How-ever, several other studies found amount ofuse to be a poor predictor of soil loss (Cole1983, Farrell and Marion 2002, Dixon et al.2004). Olive and Marion (2009) found typeof use to be a substantially greater determi-nant of soil loss than amount of use, withhorse and all-terrain vehicle use contribut-ing significantly greater amounts of soil lossthan hiking and mountain biking.

Soil loss on recreation sites can also oc-cur through sheet and rill erosion of exposedsoils. Most recreation sites are located in flat-ter terrain so soil loss is generally limited,although portions of sites, such as slopesdown to and along shorelines, can experi-ence substantial soil loss. Exposed tree rootsprovide common visual evidence of long-term soil loss. Authors J.L. Marion and H.Eagleston assessed soil loss on 81 long-estab-lished (�40 years) BWCAW campsites in2014 (unpub. data, Feb. 12, 2016), findingmean soil loss to be 22.5 yd3, a substantialamount. The majority (14.9 yd3) was attrib-uted to relatively small amounts of soil loss(2.4 in mean incision) occurring over thelarge flatter core use areas, whereas soil loss

in steeper shoreline canoe landing areas (6.4yd3) was substantially greater (9.5 in meanincision) but quite limited spatially.

Soil loss is ecologically significant dueto the extremely slow process of soil creationand the potential for secondary impactsfrom the eroded soils to water resources(e.g., turbidity and sedimentation). Themanagerial costs associated with limitingsoil loss or repairing eroded areas can be sub-stantial. Soil loss on trails and recreation sitesis essentially permanent with respect to a hu-man time scale. Such long-term change isoften considered to constitute resource “im-pairment,” which most land managementagencies are specifically charged to prevent.For visitors, eroded trails and recreation sitesmay be difficult or unsafe to use or are es-thetically displeasing. For example, trailtreads that are rutted and have numerousexposed rocks and roots are functionally de-graded; they slow traffic and increase the riskof injuries.

Campfires can dramatically change thechemical properties of the soil. The burningof firewood results in a loss of soil nutrientsand an increase in pH. Visitors who burnpaper with dyes, plastic, and other trash con-tribute to the production of toxic smoke andash accumulations that can include a num-ber of carcinogenic substances (Davies2004). Campfires substantially alter soilproperties, including a reduction in soilfauna, flora, and organic content; soil recov-ery can require 10–15 years (Fenn et al.

1976, Cole and Dalle-Molle 1982). Forthese reasons, the creation of multiple firerings on campsites and the migration of firesites around campsites over time representsignificant resource impacts.

With growing availability of long-termmonitoring data, recreation ecologists areincreasingly interested in the longitudinalchanges in recreation site conditions. For ex-ample, Cole (2013) applied two monitoringapproaches to track campsite conditions inseven wilderness areas over one to three de-cades. He found that soil and vegetationconditions on most campsites generally de-graded to a maximum point followed bysome improvements, which are attributableto site management actions to concentraterecreational activities and rehabilitate im-pacted areas (Cole 2013).

Impacts to WaterVisitor impacts to water resources pri-

marily concern the degradation of waterquality, a core issue in the context of wilder-ness sustainability. Water quality degrada-tion can be direct, resulting from activitieswith body contact, including swimming, ca-noeing, and wading (Figure 5). Indirect im-pacts on water quality are also common,contributed by recreation activities that takeplace along the shoreline or in close proxim-ity, such as hiking, camping, and wildlifeviewing (Cole and Landres 1996, Cole2008, Hammitt et al. 2015).

Water impacts can be categorized asphysical, biological, or chemical (Newsomeet al. 2012, Hammitt et al. 2015). Physicalimpacts to water can bring about tempera-ture and flow alterations, suspended matter,increased turbidity, snow compaction, anderosion. Biological impacts on water typi-cally involve the introduction or spread ofnonnative flora and fauna and increases incoliform bacteria (e.g., Escherichia coli) andprotozoa (e.g., Giardia lamblia). Chemicalimpacts are primarily related to the influx ofnutrients that lead to lowered dissolved ox-ygen rates but can also include pollution im-pacts from soap, sunscreen, food particles,and human and animal waste (Ursem et al.2009).

Recreation impacts on water in wilder-ness and protected natural areas have not re-ceived as much attention as that on otherecological components affected by visitor ac-tivities. Among the studies that exist, mostfocus on biological impacts and their impli-cations. This is probably due to the fact thatdirect impacts by recreation are often local-

Figure 3. The generalized curvilinear use-impact relationship, depicted by the thick blackline, as illustrated by measurements of six impact indicators assessed on campsites in theBWCAW (Marion 1984). Resource impacts are expressed as a percentage of the totalimpact assessed on the high-use sites.


ized, with minimal significance at the land-scape level (Cole 2008). However, these im-pacts can be severe at local scales, especiallyon small but ecologically significant waterbodies such as small streams, springs, andpotholes (Hammitt et al. 2015). For exam-ple, King and Mace (1974) conducted oneof the early empirical studies on water qual-ity impacts of wilderness recreation. Theirresults showed significant increases in coli-

form bacteria and phosphate concentrationin water bodies near campsites in the BWCAW,with pit toilets being cited as the source ofcontamination.

Recent research has devoted more at-tention to the water quality effects of packstock animals, whose trampling on vegeta-tion has long been studied (Stanley et al.1978). The recent attention is driven partlyby the information need for science-based

planning and management efforts specific topack stock use and partly by growing evi-dence that increasing presence of both hu-mans and stock animals correlates with anincrease of harmful bacteria in water, de-grading water quality in wilderness areas(Deluca et al. 1998, Derlet and Carlson2006, Clow et al. 2011, Kellogg et al. 2012).For example, in the Sierra Nevada Wilder-ness, Derlet and Carlson (2006) found 12 of

Figure 4. Heavy horse traffic has compacted and incised the main tread, which captures and retains water; subsequent hikers and horseriders seeking to avoid mudholes widen trails. Although land managers need to provide usable trails, Leave No Trace guidelines ask visitorsto stay as close to the center of the tread as possible to avoid trail widening.


15 backcountry sites with pack-animal traf-fic yielded high levels of coliform bacteria.Water conditions tested near some camp-sites in Yosemite, Kings Canyon, and Se-quoia National Parks would not pass waterquality regulations enforced by the state ofCalifornia (Clow et al. 2011). Similarly,Reed and Rasnake (2016) found elevatedlevels of E. coli and coliform bacteria insprings and streams near Appalachian Trailshelters within Great Smoky MountainsNational Park, particularly during summermonths. Heavy visitation and traffic alongstream and lake shorelines also causes vege-tation trampling that can increase the inci-dence of erosion and nutrient influxes to wa-ter bodies (Madej et al. 1994, Clow et al.2011, 2013). Nutrient loading in open bod-ies of water can contribute to algal bloomsand decreased water quality (Hammitt et al.2015). One analysis on the Merced River inYosemite National Park found a 27% in-crease in channel changes, including bankerosion due to heavy human traffic (Madejet al. 1994).

Swimming, boating, and kayaking arealso popular activities increasingly pursuedin wilderness waterways. These direct activ-ities stir otherwise settled bottom sediments,leading to turbidity, nutrient increases, andreduced levels of dissolved oxygen (Marionand Sober 1987, Butler et al. 1996, Sunder-

land et al. 2007). This suspended matter canhave substantial effects on water clarity andplant photosynthesis, harming aquatic vege-tation, macroinvertebrates, and other faunathat live in or near water (Marion and Carr2009). Increased nutrients spur heavyaquatic plant growth, reduced oxygen levels,and algal blooms (Hammitt et al. 2015).

Impacts to WildlifeWildlife are an integral component of

wilderness ecosystems but also an importantelement of the wilderness recreation experi-ence. The increasing presence of human vis-itors and their interactions with wildlife cancause changes in physiology and behaviorthat compromise wildlife health (Knightand Gutzwiller 1995, Hammitt et al. 2015).Some interactions are unsafe, and the result-ing changes in wildlife behavior may lead tounpopular and costly management decisionsto move or kill problem animals (e.g., food-attracted bears).

A significant body of research exists onwildlife ecology in wilderness (Schwartz etal. 2016). However, research focusing spe-cifically on recreation impacts to wildlife wassparse until the 1990s. Earlier research onthis topic has been summarized by Boyle andSamson (1985), Knight and Gutzwiller(1995), and Hammitt et al. (2015). Sincethe 1990s, there has been growing interest in

recreation impacts to wildlife from wildlifescientists, recreation ecologists, and humandimensions researchers (Taylor and Knight2003, Neumann et al. 2009, Monz et al.2010a, Hammitt et al. 2015). Another as-pect of wildlife impact research is related tonoise effects, as reviewed by Barber et al.(2010). The slower growth of this researchtopic is understandable, given some uniquechallenges due to the various and complexcontexts of interactions, spatial and tempo-ral lag of the effects, and varying responsesdue partly to learned behavior. It is oftenmore challenging to make generalizationsabout recreation impacts on wildlife basedon direct observations or other measures ofwildlife-human interaction (Pomerantz etal. 1988, Monz et al. 2013).

Researchers have classified human im-pact to wildlife as following four mainroutes: exploitation, disturbance, habitat al-teration, and pollution (Pomerantz et al.1988, Knight and Gutzwiller 1995). Exploi-tation entails immediate death of wildlife(vehicle collisions), whereas disturbance re-sults in harassment that can lead to the tem-poral or spatial displacement of wildlifefrom favorable to less favorable habitat. Bothare forms of direct impacts and are the resultof immediate wildlife behavioral responsesto a recreationist or recreation activity (Coleand Landres 1996, Neumann et al. 2009,Hammitt et al. 2015). Alternatively, habitatalteration and pollution are indirect formsof impact because habitat is altered, withchanges to soil, water, flora and fauna,and/or the associated effects of introducedpollutants, flora, or fauna (Knight and Gutz-willer 1995). Indirect impacts can cause analteration in behavior, distribution, survi-vorship, and reproductive ability (Pomer-antz et al. 1988, Cole and Landres 1995,Hammitt et al. 2015).

Human-wildlife interactions result invarying wildlife responses due to the charac-teristics of the human activity (the amount,type, timing, predictability, and frequencyof human interactions and the behavior ofvisitors), the wildlife (their individuality, thetiming of their breeding, nesting, and rear-ing or young), and other factors (Taylor andKnight 2003). In Point Reyes National Sea-shore in northern California, Becker et al.(2012) recorded tule elk (Cervus elephus nan-nodes) responses (standing, walking away,and running) to off-trail hikers, off-shoreboats, and other factors. Their results re-vealed that off-trail hikers triggered a higherlevel of disturbance behavior on elk than off-

Figure 5. Heavy daily summertime traffic in the Zion National Park Narrows canyon resultsin substantial trampling to shoreline vegetation and river substrates, causing a number ofdirect and indirect impacts to riparian resources.


shore boats. Other effects, such as physio-logical or population-level responses, are un-known and represent important futureresearch needs.

Wildlife responses to visitors also varyin susceptibility to primary routes of impactsdepending on human-wildlife characteris-tics, visitor or wildlife group size, and wild-life type, age, and sex (Knight and Cole1995, Steidl and Powell 2006). For exam-ple, in Yellowstone National Park, overnightcamping in wilderness areas have alteredfeeding and behavioral characteristics of theendangered grizzly bear (Ursus arctos). Cole-man et al. (2013) found that grizzly bearswere 35% more likely to roam in locationsless than 650 ft of an occupied campsite, and56% more likely to roam within 650 and1,300 ft than in a random location. Evenwhen campsite occupancy was ignored, griz-zly bears were much more likely to roamwithin 2,000 ft of a campsite, suggesting alearned food-attraction behavior (Figure 6)(Coleman et al. 2013). In addition, moose(Alces alces) in the backcountry areas of Swe-den have responded to skiing disturbancesresulting in increased movement rates (dou-bling energetic usage per 2.2 pounds of bodyweight while increasing activity ranges) andshort-term relocation (Neumann et al.2009). Bird populations can also be signifi-cantly impacted by harmful wildlife view-ing, causing decreased birth rates and nestabandonment. In the case of popular borealbird populations in Oulanka National Parkin Norway, Kangas et al. (2010) found thatincreased visitor pressure affected speciescomposition as well as bird abundance, es-pecially on open-cup nesters such as the wil-

low warbler (Phylloscopus trochilus) andwood sandpiper (Tringa glareola).

Most research has examined short-termwildlife impacts; more studies investigatinglong-term assessments are needed (Cole andLandres 1996, Kangas et al. 2010). Researchon the efficacy of management interventionsto discourage wildlife feeding and other in-appropriate human-wildlife interactions isalso needed. One example is an unobtrusiveobservation study on visitor and chipmunk(Tamias striatus) behavior in Zion NationalPark by Marion et al. (2008). They foundthat a persuasive communication treatmentimproved visitor behavior (for more details,see Marion 2016). The long-term effects ofwildlife feeding are more challenging tostudy. Hopkins et al. (2014) present an in-novative approach to overcoming this chal-lenge. They examined the long-term effectsof bear management policies on the dietarycomposition of American black bears (Ursusamericanus). Using stable isotopes derivedfrom bear tissues, they estimated the propor-tion of human-derived foodstuffs and foodwaste (“human foods”) in the diets of hu-man food-conditioned bears over the pastcentury in Yosemite National Park. Theyfound that the proportion of human foodsin bear diets show strong correspondencewith bear management policies, from “in-tentional” feeding by park personnel andvisitors (1923–1971) through the subse-quent “no-feeding” policy, demonstratingthe long-term effects of management policy.

More research is needed on how recre-ation impacts challenge and influence wild-life (Taylor and Knight 2003, Monz et al.2010a, Marzano and Dandy 2012). Existingstudies look at charismatic megafauna suchas grizzly bears, bald eagles (Haliaeetus leuco-cephalus), and wolves (Canis lupus), but fewinvestigate similar implications on arthro-pods, reptiles, amphibians, or small fish(Monz et al. 2013). In addition, some recre-ation activities are examined more closelythan others, creating knowledge gaps. Forexample, hiking impact studies are moreprevalent than studies of rock climbing orspelunking impacts (Taylor and Knight2003). Revisiting and replicating past re-search and conducting longitudinal studiesalso help us understand wildlife recreationimpacts over a long period of time (Ham-mitt et al. 2015).

Summary and ConclusionsAre we loving our wilderness and parks

to death? We have all heard that question,

prompted by concerns that millions of visi-tors drawn to our protected natural areas ev-ery year are degrading the plants, soils, wa-ter, and wildlife these areas were establishedto protect. Although more intensively vis-ited wildland areas are degraded by recre-ational visitation, the vast majority of pro-tected lands see little use and impact (Figure 7).Recreation ecology is a field of study that de-scribes the types and severity of these re-source impacts and how they are influencedby the type, number, and behavior of visi-tors. Managers require objective informa-tion describing these resource changes sothey can evaluate their effects on ecosystemconditions and processes and the quality ofvisitor experiences. Information describingvisitor resource impacts is also needed to de-termine their acceptability and the need formanagement interventions. Recreation ecol-ogy also investigates relationships betweenresource impacts and causal use-related fac-tors and other influential factors such as to-pography, vegetation type, and substrates.Managers seeking to avoid or minimize vis-itor resource impacts require more compre-hensive information about these interrela-tionships so they can improve their visitoruse management practices and the sustain-ability of their recreation infrastructure, par-ticularly trails and recreation sites.

This article has provided a concise re-view and synthesis of the recreation ecologyliterature. It shows that we know most aboutimpacts to vegetation and soil, that knowl-edge about impacts to wildlife has increasedsignificantly since 2000, and that researchon impacts to water quality has lagged be-hind. The body of knowledge on recreationimpacts has demonstrated its utility in in-forming visitor planning, management andcommunication strategies and actions beingimplemented in wilderness and other pro-tected natural areas (Cole 2009, Hammitt etal. 2015). Specifically, the contributions tomanagement are most evident in indicatordevelopment in support of carrying capacityand visitor use management frameworks,the siting, management, and restoration ofrecreation infrastructure to increase sustain-ability, and the development of more effec-tive Leave No Trace practices and persuasivecommunication techniques. More discus-sion on the applications of this knowledgebase is provided in the accompanying article(Marion 2016).

The body of recreation ecology litera-ture continues to grow, particularly as a re-sult of the adoption of recreation ecology as

Figure 6. Leave No Trace practices directoutdoor visitors to not feed wildlife and tostore food and trash securely to preventbears and other wildlife from associatinghumans with food.


a focused line of research by our interna-tional colleagues (Pickering 2010, Newsomeet al. 2012, Barros and Pickering 2015). Theimproved knowledge and sharing of effec-tive visitor impact management practiceswill certainly benefit the management of USwilderness, as some impacts, influential fac-tors, and management techniques are com-mon across different protected natural areas.

Monz et al. (2010a) highlighted severalsignificant research gaps in recreation ecol-ogy, including a stronger conceptual andtheoretical foundation, better predictabilitythrough modeling, broadening spatial andtemporal scales, integration with social andmanagement science, and better under-standing of synergistic effects with otherstressors. These research gaps remain and aredirectly applicable to the wilderness context.Other research needs respond to the imbal-ance of research attention received by vari-ous wilderness ecosystems and recreation ac-tivities. The growing research interest insoundscape and dark sky as resource compo-nents presents a fruitful avenue for recre-ation ecology research that examines the im-pacts and visitor activities and related noiseon these intangible resources important to

both wildland ecology and visitor experi-ences (Hammitt et al. 2015).

Finally, emerging and diversifying rec-reation activities in wilderness partly en-abled by technology, such as the use ofglobal positioning systems (GPS) units orGPS-enabled smartphones for geocaching,off-trail hiking, locating campsites, biking,or even drones, also present important re-search questions about recreation impacts(both ecological and social) that must be ad-dressed before we can identify their appro-priateness and effective management strate-gies. Some questions can be addressed usingconventional assessment and monitoringmethods, but new research designs and mea-sures may be required to fully understandthe impacts of some new activities. By ad-dressing these research needs, we will con-tinue to advance the science and practice ofwilderness management, integrating the im-portant goals of sustaining natural resourcesand providing outstanding opportunities forwilderness recreation.

Endnote1. For more information, see www.wilderness.

net.

Literature CitedALESSA, L., AND C.G. EARNHART. 2000. Effects of

soil compaction on root and root hair mor-phology: Implications for campsite rehabilita-tion. P. 99–104 in Wilderness science in a timeof change conference—Vol. 5: Wilderness ecosys-tems, threats, and management, 1999 May 23–27, Missoula, MT, Cole, D.N., S.F. McCool,W.T. Borrie, and J. O’Loughlin (comps.).USDA For. Serv., Proc. RMRS-P-15-Vol-5,Rocky Mountain Research Station, Ogden,UT.

BARBER, J.R., K.R. CROOKS, AND K.M. FRISTRUP.2010. The costs of chronic noise exposure forterrestrial organisms. Trends Ecol. Evol. 25(3):180–189.

BARROS, A., AND C.M. PICKERING. 2015. Impactsof experimental trampling by hikers and packanimals on a high-altitude alpine sedgemeadow in the Andes. Plant Ecol Divers. 8(2):265–272.

BECKER, B.H., C.M. MOI, T.J. MAGUIRE, R. AT-KINSON, AND N.B. GATES. 2012. Effects of hik-ers and boats on tule elk behavior in a nationalpark wilderness area. Hum. Wildl. Interact.6(1):147–154.

BOYLE, S.A., AND F.B. SAMSON. 1985. Effects ofnonconsumptive recreation on wildlife: A re-view. Wildl. Soc. Bull. 13(2):110–116.

BUTLER, B., A. BIRTLES, R. PEARSON, AND K.JONES. 1996. Ecotourism, water quality and wettropics streams. Rep. to the CommonwealthDepartment of Tourism, Australian Centre forTropical Freshwater Research, Townsville,QLD, Australia.

CLOW, D.W., R.S. PEAVLER, J. ROCHE, A.K. PAN-ORSKA, J.M. THOMAS, AND S. SMITH. 2011. As-sessing possible visitor-use impacts on waterquality in Yosemite National Park, California.Environ. Monitor. Assess. 183(1):197–215.

CLOW, D.W., H. FORRESTER, B. MILLER, H.ROOP, J.O. SICKMAN, H. RYU, AND J.S. DO-MINGO. 2013. Effects of stock use and back-packers on water quality in wilderness in Se-quoia and Kings Canyon National Parks,USA. Environ. Manage. 52:1400–1414.

COLE, D. 1983. Assessing and monitoring back-country trail conditions. USDA For. Serv., Res.Pap. INT-303, Intermountain Forest andRange Experiment Station, Ogden, UT. 10 p.

COLE, D. 1987. Effects of three seasons of exper-imental trampling on five montane forest com-munities and a grassland in western Montana,USA. Biol. Conserv. 40:219–244.

COLE, D. 1995a. Experimental trampling of veg-etation. I. Relationship between trampling in-tensity and vegetation response. J. Appl. Ecol.32:203–214.

COLE, D. 1995b. Experimental trampling of veg-etation. II. Predictors of resistance and resil-ience. J. Appl. Ecol. 32:215–224.

COLE, D. 2008. Ecological impacts of wildernessrecreation and their management. P. 395–438in Wilderness management: Stewardship andprotection of resources and values, 4th ed., Daw-son, C.P., and J.C. Hendee (eds.). FulcrumPress, Golden, CO.

Figure 7. Even for the highly visited Boundary Waters Canoe Area Wilderness, more than98% of the area remains in pristine natural condition. Field research assistant ClaireUnderwood enjoying a BWCAW sunset after a day spent measuring camping impacts.(Photo by Jeff Marion.)


http://www.wilderness.net

http://www.wilderness.net

COLE, D. 2013. Changing conditions on wildernesscampsites: Seven case studies of trends over 13 to32 years. USDA For. Serv., Gen. Tech. Rpt.RMRS-GTR-300, Rocky Mountain ResearchStation, Fort Collins, CO. 99 p.

COLE, D., AND J. DALLE-MOLLE. 1982. Managingcampfire impacts in the backcountry. USDAFor. Serv., Gen. Tech. Rpt. INT-135, Inter-mountain Research Station, Ogden, UT. 20 p.

COLE, D.N., AND P.B. LANDRES. 1995. Indirecteffects of recreation on wildlife. P. 183–202 inWildlife and recreationists: Coexistence throughmanagement and research, Knight, R.L., andK.J. Gutzwiller (eds.). Island Press, Washing-ton, DC.

COLE, D.N., AND P.B. LANDRES. 1996. Threats towilderness ecosystems: Impacts and researchneeds. Ecol. Applic. 6(1):168–184.

COLE, D., AND C. MONZ. 2002. Trampling dis-turbance of high-elevation vegetation, WindRiver Mountains, Wyoming, USA. Arctic Ant-arctic Alpine Res. 34(4):365–376.

COLE, D., AND C. MONZ. 2003. Impacts ofcamping on vegetation: Response and recoveryfollowing acute and chronic disturbance. En-viron. Manage. 32(6):693–705.

COLEMAN, T.H., C.C. SCHWARTZ, K.A. GUNTHER,AND S. CREEL. 2013. Influence of overnightrecreation on grizzly bear movement and be-havior in Yellowstone National Park. Ursus24(2):101–110.

DAVIES, M.A. 2004. What’s burning in your camp-fire? Garbage in, toxics out. USDA For. Serv.,Tech Tip 0423-2327-MTDC, MissoulaTechnology and Development Center, Mis-soula, MT. 8 p.

DELUCA, T.H., W.A. PATTERSON, W.A. FRE-IMUND, AND D.N. COLE. 1998. Influence ofllamas, horses and hikers on soil erosion fromestablished recreation trails in western Mon-tana, USA. Environ. Manage. 22:255–262.

DERLET, R.W., AND J.R. CARLSON. 2006. Coli-form bacteria in Sierra Nevada wilderness lakesand streams: What is the impact of backpack-ers, pack animals, and cattle? Wild. Environ.Med. 17(1):15–20.

DICKENS, S.J., F. GERHARDT, AND S.K. COL-LINGE. 2005. Recreational portage trails as cor-ridors facilitating non-native plant invasions ofthe Boundary Waters Canoe Area Wilderness.Conserv. Biol. 19(5):1653–1657.

DIXON, G., M. HAWES, AND G. MCPHERSON.2004. Monitoring and modelling walkingtrack impacts in the Tasmanian WildernessWorld Heritage Area, Australia. J. Environ.Manage. 71:305–320.

EAGLESTON, H., AND C. RUBIN. 2013. Impacts ofwinter recreation on snowmelt erosion,Blewett Pass, WA. Environ. Manage. 51(1):167–181.

FARRELL, T.A., AND J.L. MARION. 2002. Trail im-pacts and trail impact management related tovisitation at Torres del Paine National Park,Chile. Leisure/Loisir 26(1–2):31–59.

FENN, D.B., G.J. GOGUE, AND R.E. BURGE. 1976.Effects of campfires on soil properties. USDI Na-tional Park Service, Ecol. Serv. Bull. No. 5,Washington, DC. 16 p.

HAMMITT, W.E., D.N. COLE, AND C.A. MONZ.2015. Wildland recreation: Ecology and man-agement, 3rd ed. John Wiley & Sons, NewYork. 328 p.

HARTLEY, E. 1999. Visitor impacts at Logan Pass.Glacier National Park: A thirty-year vegetationstudy. P. 297–305 in On the frontiers of conser-vation: Proc. of the 10th conference on researchand management in national parks and on pub-lic lands, Harmon, D. (ed.). George WrightSociety, Hancock, MI.

HILL, W., AND C.M. PICKERING. 2009. Differ-ences in the resistance of three subtropical veg-etation types to experimental trampling. J. En-viron. Manage. 90:1305–1312.

HOPKINS, J.B. III, P.L. KOCH, J.M. FERGUSON,AND S.T. KALINOWSKI. 2014. The changinganthropogenic diets of American black bearsover the past century in Yosemite NationalPark. Front. Ecol. Environ. 12(2):107–114.

JAMES, T., D. SMITH, E. MACKINTOSH, M. HOFF-MAN, AND P. MONTI. 1979. Effects of campingrecreation on soil, Jack pine (Pinus banksiana),and understory vegetation in a northwesternOntario park. For. Sci. 25:233–249.

KANGAS, K., M. LUOTO, A. IHANTOLA, E.TOMPPO, AND P. SILKAMAKI. 2010. Recreation-induced changes in boreal bird communitiesin protected areas. Ecol. Applic. 20(6):1775–1786.

KELLOGG, D.S., P.F. ROSENBAUM, D.L. KISKA,S.W. RIDDELL, T.R. WELCH, AND J. SHAW.2012. High fecal hand contamination amongwilderness hikers. Am. J. Infect. Control 40(9):893–895.

KING, J.C., AND A.C. MACE. 1974. Effects of rec-reation on water quality. J. Water Pollut. Con-trol Fed. 46(11):2453–2459.

KNIGHT, R.L., AND D.N. COLE. 1995. Wildliferesponses to recreationists. P. 51–70 in Wild-life and recreationists: Coexistence through man-agement and research, Knight, R.L., and K.J.Gutzwiller (eds.). Island Press, WashingtonDC.

KNIGHT, R.L., AND K.J. GUTZWILLER. 1995.Wildlife and recreationists: Coexistence throughmanagement and research. Island Press, Wash-ington, DC. 373 p.

LANDRES, P., W.M. VAGIAS, AND S. STUTZMAN.2011. Using wilderness character to improvewilderness stewardship. Park Sci. 28(3):44–48.

LEI, S.A. 2004. Soil compaction from humantrampling, biking, and off-road motor vehicleactivity in a blackbrush (Coleogyne ramosis-sima) shrubland. West. North Am. Nat. 64(1):125.

LEUNG, Y.-F., AND J.L. MARION. 1996. Trail deg-radation as influenced by environmental fac-tors: A state-of-knowledge review. J. Soil WaterConserv. 51:130–136.

LEUNG, Y.-F., AND J.L. MARION. 1999a. Assessingtrail conditions in protected areas. Applicationof a problem assessment method in GreatSmoky Mountains National Park. Environ.Conserv. 26:270–279.

LEUNG, Y.-F., AND J.L. MARION. 2000. Recre-ation impacts and management in wilderness:A state-of-knowledge review. P. 23–48 in Wil-

derness science in a time of change conference—Vol. 5: Wilderness ecosystems, threats, and man-agement, 1999 May 23–27, Missoula, MT,Cole, D.N., S.F. McCool, W.T. Borrie, and J.O’Loughlin (comps.). USDA For. Serv., Proc.RMRS-P-15-Vol-5, Rocky Mountain Re-search Station, Ogden, UT.

LEUNG, Y.-F., J.L. MARION, AND T.A. FARRELL.2008. Recreation ecology in sustainable tour-ism and ecotourism: A strengthening role. P.19–37 in Tourism, recreation and sustainabil-ity: Linking culture and the environment, 2nded., McCool, S.F., and R.N. Moisey (eds.).CABI, Wallingford, UK.

LIDDLE, M.J. 1997. Recreation ecology. Chapmanand Hall, London, UK. 639 p.

MADEJ, M.A., W.E. WEAVER, AND D.K. HAGANS.1994. Analysis of bank erosion on the MercedRiver, Yosemite Valley, Yosemite NationalPark, California, USA. Environ. Manage.18(2):235–250.

MARION, J.L. 1984. Ecological changes resultingfrom recreational use: A study of backcountrycampsites in the Boundary Waters Canoe AreaWilderness, Minnesota. PhD dissertation,Dept. of Forest Resources, Univ. of Minne-sota, St. Paul, MN. 279 p.

MARION, J.L. 2016. A review and synthesis ofrecreation ecology research supporting carry-ing capacity and visitor use management deci-sionmaking. J. For. 114(3):339–351.

MARION, J.L., AND C. CARR. 2009. Backcountryrecreation site and trail conditions: Haleakala�National Park. Final Management Rep., Vir-ginia Tech College of Natural Resources, For-estry/Recreation ResourcesManagement,Blacks-burg, VA. 94 p.

MARION, J.L., AND D.N. COLE. 1996. Spatial andtemporal variation in soil and vegetation im-pacts on campsites: Delaware Water Gap Na-tional Recreation Area. Ecol. Applic. 6(2):520–530.

MARION, J.L., D.N. COLE, AND S.P. BRATTON.1986. Exotic vegetation in wilderness areas. P.114–120 in Proc.—National Wilderness Re-search Conference: Current Research, Lucas,R.C. (comp.). USDA For. Serv., Gen. Tech.Rep. INT-212, Intermountain Research Sta-tion, Ogden, UT.

MARION, J.L., R.G. DVORAK, AND R.E. MAN-NING. 2008. Wildlife feeding in parks: Meth-ods for monitoring the effectiveness of educa-tional interventions and wildlife foodattraction behaviors. Hum. Dimens. Wildl.13(6):429–442.

MARION, J.L., AND L. MERRIAM. 1985a. Predict-ability of recreational impact on soils. Soil Sci.Soc. Am. J. 49(3):751–753.

MARION, J.L., AND L. MERRIAM. 1985b. Recre-ational impacts of well-established campsites inthe Boundary Water Canoe Area Wilderness.Agri. Exp. Station Bull., AD-SB-2502, Univ.of Minnesota, St. Paul, MN. 16 p.

MARION, J.L., AND T. SOBER. 1987. Environmen-tal impact management in the Boundary Wa-ters Canoe Area Wilderness. North. J. Appl.For. 4(1):7–10.

MARZANO, M., AND N. DANDY. 2012. Recre-ationist behavior in forests and the disturbance


of wildlife. Biodivers Conserv. 21(11):2967–2986.

MONZ, C.A., D.N. COLE, Y.-F. LEUNG, AND J.L.MARION. 2010a. Sustaining visitor use in pro-tected areas: Future opportunities in recreationecology research based on the USA experience.Environ. Manage. 45(3):551–562.

MONZ, C., J. MARION, K. GOONAN, R. MAN-NING, J. WIMPEY, AND C. CARR. 2010b. Assess-ment and monitoring of recreation impactsand resource conditions on mountain sum-mits: Examples from the Northern Forest,USA. Mount. Res. Dev. 30(4):332–343.

MONZ, C.A., C.M. PICKERING, AND W.L. HAD-WEN. 2013. Recent advances in recreationecology and the implications of different rela-tionships between recreation use and ecologi-cal impacts. Front. Ecol. Environ. 11(8):441–446.

MORTENSON, C. 1989. Visitor impacts withinthe Knobstone Trail corridor. J. Soil WaterConserv. 44(2):156–159.

NEPAL, S. 2003. Trail impacts in Sagarmatha(Mt. Everest) National Park, Nepal: A logisticregression analysis. Environ. Manage. 32(3):312–321.

NEPAL, S., AND P. WAY. 2007. Characterizing andcomparing backcountry trail conditions inMount Robson Provincial Park, Canada. Am-bio. 36(5):394–400.

NEUMANN, W., G. ERICSSON, AND H. DETTKI.2009. Does off-trail backcountry skiing dis-turb moose? Eur. J. Wildl. Res. 56(4):513–518.

NEWSOME, D., S.A. MOORE, AND R.K. DOWL-ING. 2012. Natural area tourism: Ecology, im-pacts and management, 2nd ed. Channel View,Bristol, UK. 480 p.

OLIVE, N., AND J. MARION. 2009. The influenceof use-related, environmental and managerialfactors on soil loss from recreational trails.J. Environ. Manage. 90:1483–1493.

PESCOTT, O.L., AND G.B. STEWART. 2014. As-sessing the impact of human trampling on veg-etation: A systematic review and meta-analysisof experimental evidence. PeerJ 2:e360.

PICKERING, C. 2010. Ten factors that affect theseverity of environmental impacts of visitors inprotected areas. Ambio. 39:70–77.

PICKERING, C., AND W. HILL. 2007. Impacts ofrecreation and tourism on plant diversity andvegetation in protected areas in Australia.J. Environ. Manage. 85:791–800.

PICKERING, C., W. HILL, D. NEWSOME, AND Y.-F.LEUNG. 2010. Comparing hiking, mountainbiking and horse riding impacts on vegetationand soils in Australia and the United States ofAmerica. J. Environ. Manage. 91:552–562.

POMERANTZ, G.A., D.J. DECKER, G.R. GOFF,AND K.G. PURDY. 1988. Assessing impact ofrecreation on wildlife: A classification scheme.Wildl. Soc. Bull. 16(1):58–62.

REED, B.C., AND M.S. RASNAKE. 2016. An assess-ment of coliform bacteria in water sources nearAppalachian Trail shelters within the GreatSmoky Mountains National Park. Wild. Envi-ron. Med. 27(1):107–110.

SCHWARTZ, M., B. HAHN, AND B. HOSSACK.2016. Where the wild things are: A researchagenda for studying the wildlife-wilderness re-search. J. For. 114(3):311–319.

STANLEY, J.T. JR., H.T. HARVEY, AND R.J.HARTESVELDT (EDS.). 1978. A report on the wil-derness impact study: The effects of human rec-reational activities on wilderness ecosystemswith special emphasis on Sierra Club wilder-ness outings in the Sierra Nevada. Sierra Club,Outing Committee, San Francisco, CA. 290 p.

STEIDL, R.J., AND B.F. POWELL. 2006. Assessingthe effects of human activities on wildlife.George Wright Forum 23(2):50–58.

STRIKER, G.G., F.P.O. MOLLARD, A.A. GRI-MOLDI, R.J.C. LEON, AND P. INSAUSTI. 2011.

Trampling enhances the dominance ofgraminoids over forbs in flooded grassland me-socosms. Appl. Veg. Sci. 14:95–106.

SUN, D., AND M.J. LIDDLE. 1993. Trampling re-sistance, stem flexibility and leaf strength innine Australian grasses and herbs. Biol. Con-serv. 65(1):35–41.

SUNDERLAND, D., T.K. GRACZYK, L. TAMANG,AND P.N. BREYSSE. 2007. Impact of bathers onlevels of Cryptosporidium parvum oocysts andGiardia lamblia cysts in recreational beach wa-ters. Water Res. 41(15):3483–3489.

TAYLOR, A.R., AND R.L. KNIGHT. 2003. Wildliferesponses to recreation and associated visitorperceptions. Ecol. Applic. 13(4):951–963.

THURSTON, E., AND R.J. READER. 2001. Impactsof experimentally applied mountain bikingand hiking on vegetation and soil of a decidu-ous forest. Environ. Manage. 27(3):397–409.

UNDERWOOD, E.C., R. KLINGER, AND P.E.MOORE. 2004. Predicting patterns of non-na-tive plant invasions in Yosemite National Park,California, USA. Divers. Distrib. 10(5–6):447–459.

URSEM, C., S. EVANS, K.A. GER, J.R. RICHARDS,AND R.W. DERLET. 2009. Surface water qual-ity along the central John Muir Trail in theSierra Nevada Mountains: Coliforms and al-gae. High Alt. Med. Biol. 10(4):249–255.

WANEK, W. 1971. Snowmobile impacts on veg-etation, temperatures and soil microbes. P.161–229 in Proc. 1971 snowmobile and off roadvehicle research symposium, Chubb, M. (ed.).Tech. Rep. 8, Dept. of Park and Rec. Re-sources, Michigan State Univ., East Lansing,MI.

WIMPEY, J., AND J. MARION. 2010. The influenceof use, environmental and managerial factorson the width of recreational trails. J. Environ.Manage. 90:2028–2037.


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