Impacts of Hiking and Camping on Soils and Vegetation: a Review

David N. Cole Aldo Leopold Wilderness Research Institute, Forest Service, Missoula, Montana USA

Introduction havedrawn moreexamples from my ownwork than might be representative because 1am most Ecotourism effects local cMivironments in many familiar with their details. Additional sources ways. Although some ot the most dramatic envi can be found in several textbooks (Liddle, ronmental changes result from development of 1997; Hammitt and Cole, 1998; Newsome et the infrastructure to support tourism, more a/., 2002) and reviews of the literature (Cole, widespread impacts result from the recreational 1987, 2002; Leung and Marion, 2000). activities that tourists engage in. For ecotourists In this chapter, I do not distinguish be engaged in adventurous pursuits, hiking and tween recreation and tourism. Fromthe point of camping are perhaps the most common activ view of impacts to soils and vegetation, differ ities that can have profound ecological impacts. ences between the two seem negligible. This is particularly true in more remote places, Ecotourism suggests environments character protected as parks or wilderness. ized by near-natural conditions, low levels of Of the many environmental effects of development and crowding. Fortuitously, most hiking and camping, impacts on soil and vege c:)f the literature on recreation impacts has tation have been most thoroughly explored. been conducted in such environments, making Consequently, the literature on this subject is application to ecotourism straightforward. voluminous and is a challenge to review thor oughly. The strategy of this chapter is to provide an historical context for the development of this Hiking and Camping as Activities literature, discuss the types of studies that have been employed (cvich with inherent strengths Humans have walked and camped for as long and weaknesses) and briefly assess the geo as they have existed. Only in recent centuries, graphical distribution of research. Emphasis is particularly in developed countries, has there placed on development of generalities from the heen little need for large portions of the popu literature and identification of critical knowl lation to walk from place to place. In the past edge ga[:)s, rather than a comprehensive review halfcentury, this trend hasreversed. As thepro of many site- and context-specific descriptive portion of people with substantial leisure time studies. I try to identify th(^ early papers that has increased, people areturning to hiking and provided the genesis of ideas and conc epts, as camping as recreational activities (Fig. 4.1). In well as recent papers that extend earlier work the USA, for example, two-thirds of the popu conceptually and geograi)hically. Inevitably I lation engages in walking for pleasure and

''c, ( _AB Inti'rnation.il J0()4. tin ironnicnhil Imp.u ts ot tcotouri^m led. R. Buckley) 41 42 D.N. Cole

Rg.4.1. Recreational hiking and backpacking have increased dramaticaiiy in the past few decades. about one-quarter hikes and camps (Cordell world (e.g. much of Europe, Nepal and New and Super, 2000). Increased Interest in ecotour- Zealand), long-distance trekkers usually over ism reflects this trend and its dissemination night in lodges or shelters, but, in many places, around the globe. the tradition involves overnight camping. Hiking has always been more ubiquitous Camping may occur on designated campsites; than camping, particularly in more developed informal, long-established sites; and even on and less remote places. In road-accessible places that have never been camped on betore. places, with well-developed infrastructure, The value of research on recreation im most hiking may occur on highly engineered pacts to scjils and vegetation seems generally trails designed to absorb the impacts of hiking greater in less-developed and more remote and to confine those impacts to the designed lands. This has nothing to do with the relative trail system and nodes of activity (e.g. view amount or importance of recreation in these points, picnic sites, etc.). Most hiking is of short places. In less-developed and more remote duration, less than 1 day and often for just an places, management is more complex, and the hour or two, with tourists staying the night in knowledge required to manage eftectively is some sort of lodging. In addition to staying in greater. Management relies less on engineering overnight lodging, many people camp in road- and on separating the natural environment accessible developed campgrounds, which from recreational use. Therefore, it is more crit ideally are designed to confine traffic to sur ical to understand the inherent durability ol the faces that are hardened to absorb use. In these natural environment, and bow much of what situations, impacts to soils and vegetation can types of use the environment can su/iport. The be limited despite very high visitation levels. standards for acceptable levels ot impact are Where people venture offthe trail system, how also likely to he more stringent, and concern ever, impacts can be pronounced. about the obtrusiveness of management is Less-developed and more remote areas are likely tcj he greater. This management complex used in more variable ways. Day hiking on ity, I think, explains the fact that although most engineered trails still occurs, but overnight visitation occurs c^n more developed lands, hiking on less-developed trails and even off- most research has been conducted in less- trail travel also occurs. In certain parts of the developed parks and wilderness

Historical Context of Research research showed that impact occurs wherever use occurs, leading Frissell to suggest that the Research on tlie ecol()t;it al impacts nt recrea decision facing recreation managers is how tion has a short histors. Althoiij^li there were a much impact is acceptable - not whether or not few isolated earU studies ol the ecolot^ical to allow impact. This obserx'ation provided the impacts of toLirists iMeinecke, 1^28) and of conceptual foundation for planning processes vegetation sulijected to trampling (Bates, such as the Limits of Acceptable Change 1935), the 19()()s was the dec ade when interest (Stankey et a/., 1985). Frissell's data also Illus in recreation impacts first decelo[")ed widely. trated the curvilinear nature of the relationship Not coincidentally, it was the l')(it)s when the between amount of use and amount of impact, demand for outdoor recreation first exidoded in although it was another 15 years before the much of the developed world. This earliest generality of this finding and its significance to work was descriptive, highK' site-S|X^cific, recreation management was articulated (Cole, seldom published, and largeK' ccMifined to the 1981a). Frissell (1978) was also among the first USA and western Europe. Few researchers ever to publish suggested methods for monitoring conducted more than one stuck'. wilderness campsites. By the early 197()s, intcMcst had grown Efforts to develop generalities and the man enough I'or collaborative and cumulative agement implications of recreation ecology research to be supported. The term 'recreation were substantially increased when governmen eccdogy', the most commoti descrifitor of tal research institutions hired recreation ecolo- research on the c>nvironmental ellec ts of recre- gists. Since the late 1970s (Cole, 1978), my atic3n, was probably coined about this time. B\' position with the US Forest Service has allowed 1973, in Great Britain, the Rec reation Ecology me to focus my professional work on recreation Research Grou|:) was convening regularlv to ecology, jetfMarion has held a similar position share information. The lirst pionc>ers in recrcM- with the National Park Service (now the US tion ecology also began work in the earlv Geological Survey) since the mid-1980s. This 1970s. Neil Baytield (1 971, 197 1, 1979) devel has provided the opportunity for more rigorous oped the first sustained [Kogramme of recrea study of recreation ecology. Ithas been possible tion ecology research, a 20-year [programme of to use multiple methodologies to examine government-lunded work on trampling and impacts (Marion and Cole, 1996), to develop footpath impacts in the mountains of Scotland models of factors that influence impacts (Cole, and England. He was among the first to [propose 1987, 1992), to search for generality across dif methods for monitoring trail im[iacts and to ferent environments (Cole, 1995a), to study investigate means ol restoring damaged recrea trends over time (Cole, 1993) and to work at tion sites. Michael Licldle began a liletime (4' multiple spatial scales (Cole, 1996). It has also work in academia on rec reation impacts, first in provided more opportunity to apply research Great Britain (Liddle and Greig-Smith, 1975) results to the development of management strat and later in Australia (Liddlc> and Kay, 1987). egies (Cole, 1987, 2002; Hammitt and Cole, Notably, Liddle (1975a,b) was among the first 1998; Leung and Marion, 2000) and monitoring to search for generalities about recreation techniques (Cole, 1989a; Marion and Leung, impacts and his carec>r culminated in a com 2001). prehensive textbook on recreation ecologv The geographic distribution of recreation (Liddle, 1997). ecology research has also expanded. Prior to The earliest students of rec reation ecologv the 1980s, recreation ecology research was in the USA did not pursue c

^ .V

rWit »• eV*

w ^

Fig. 4.2. Much of the research in recreation ecology has been conducted in mountainous environments.

Leung and Neller, 1995). Inthe 1980s, research (1990) applied the findings of recreation ecol expanded in developed countries around the ogy to ecotourism and Tracy Earrell applied Jeff world, most notably in South Africa (Garland, Marion's impact monitrjring procedures in 1987) and Australia. Notable in Australia is the Central and South America (Earrell and Marion, work of Liddle and his students (Liddle and 2001 a,bj. Thyer, 1986; Sun and Liddle, 1993a,b) and The ecosystems in which recreation ecol research related to management of World ogy research has been conducted has expanded Heritage Areas in Tasmania (Whinam et al., along with the geographical distribution of 1994; Whinam and Chilcott, 1999) and the studies. The earliest work occurred in moun Great Barrier Reef(Liddle and Kay, 1987). tainous and coastal environments, due to the In the 1990s, perhaps in response to attraction of tourists to these locations (Eig. 4.2). increased ecotourism and recognition of its To this day, the preponderance of work is still potential environmental consequences, recrea conducted in the mcjuntains and, to a lesser tion ecology research has expanded into devel degree, along coasts. Although the earliest work oping countries and ecotourism destinations in the mountains was typically in the alpine and around the globe. Recent studies have been subalpine zones, recently more research has conducted in the Middle East - in Israel (Kutiel been conducted at lower elevations (e.g. EHall and Zhevelev, 2001) and Egypt (Hawkins and and Kuss, 1989; Leung and Marion, 1999a). Roberts, 1993) - as well as in the tropics - in Much of the recent coastal work has shifted to Central and South America (Boucher et al., recreational impacts on reefs and intertidal 1991; Earrell and Marion, 2001a), Africa (Obua areas (Liddle and Kay, 1987; Elawkins and and Harding, 1997) and South-East Asia (Jusoff, Roberts, 1993; Rou[3bael and Inglis, 2002). 1989). It has expanded throughout the temper Other environments recently studied include ate lands of the southern hemisphere - in New riparian (Marion and (a)le, 199()) and desert Zealand (Stewart and Cameron, 1992) and in environments (Cole, 19tU)). Chile (Earrell and Marion, 2001b) - and even the sub-Antarctic (Scott and Kirkpatrick, 1994). Much of this generation of research has drawn Research Designs directly from the research techniques and protocols developed bythe original generation Eour different research designs have been of recreation ecologists. Buckley and Pannell employed as a means of studyifig rec reatiotial Impacts of Hiking and Camping on Soils and Vegetation 45

impacts (Cole, 1MH71. I ach ot these (iesie,ns has However, control sites are never perfect repli strengths and weaknessi'^. The \akiahle per cates of pre-existing conditions and, in some spective of each clesigti is ri'lietted in the fact situations, the difficulty of finding good con that each was used in earl\ rei realion t>c c)log\ trols makes it impossible to use this approach. research and each continues to hc> used toda\'. A further variant of the descriptive field The most common design, [larticularK in sur\'ey is the before-and-after natural experi highly a[:)pli(>d research, designed to assess ment. This design involves assessing conditions impacts to an entire park, campgroimd or trail before and after recreational use occurs, or system, is the desc ripti\'e field sur\e\. \'egeta- before and after a change in management tion and soil paramcMers on rec reation sites are regime. Ideally, identicalmeasures aretaken on measured for the [Hir|)()sc> of assessing ccirrerit control sites that are not subjected to use or a conditions. Environmental acid usc> c haracteris chatige in management. In this case, change tics are otten simultaneousK' assessc>d and then resulting from management is measured correlated with varitition in impac ts to soil and directly. An early example of this approach is vegetation. E.xamples of tliis afif^roach include Merriam and Smith's (1974) study of impacts Bayfield's (1 97T) work on Scottish trails, as well resulting from initial use of newly opened as the work ot Marion and his students on trails campsites. Spildie et a/. (2000) used this design and campsites in the eastern USA and in to assess the effectiveness of a management Central and South America da'ung and Marion, programme designed to confine and reduce 1999a,b; Farrell and Marion, 2t)0]a,hi. The campsite impacts associated with packstock. value of this approach is that im|xu t conditions Typically, such studies are conducted in one can be surveyed over large areas rapidK' and place at one point in time. Consequently, it can with minimal training. Surveys provide a snap be difficult to assess the general applicabilityof shot of conditions at a point in time and, when results. repeated, can be used to assess trcaids ovcy The three variants of the descriptive field time. ConsecjLiently, such studies can provide survey have the advantage of realism and pro much ot the toundational intormation needed viding highly relevant site-specific information, to guide day-to-day management. However, if but they all suffer, to varying degrees, in their one's goal is to understand cause-and-eftect, ability to identify cause-and-effect and to con this is the least useful of the researc h designs. tribute to general knowledge. Thealternative is One can speculate about cause and effect from the simulated experimental approach. With this correlational analyses, but apparent relation approach, researchers carefully control useand ships can be s|nirious and true relationships environmental factors in a replicated design can be missed due to (be contounding of inter that maximizes insights into cause and effect. vening variables. Ba)'field (1971) was perhaps the first to employ A common variant of the descriptive experimental trampling by humans, although survey is the addition of measures taken on Wagar (19(il) trampled vegetation using an undisturbed control sites that, when compared artificial 'tamp'. More recently, Cole and Bay- with recreation sites, provide an estimate of field (1993) developed a standard protocol tor change resulting I'rom recreation use. This conducting trampling experiments. This proto amounts to using spatial dilTerences (used col has been applied in many different vegeta versus unused) to inter temporal change (pre- tion types, from mountainous areas of the USA versus post-use). In sue h studic^s, it is common (Cole, 1995a) to such places as Arctic tundra tfj compare im|)ac ts on catc^gories of sites that (Monz, 2002), sand dunes in France (Lemauviel vary either in use or environmcmlal charac tcM is- and Roze, 2003) and forested communities in tics. An early example is Erissell atui Duncan's Ltganda (Pratt, 1997). Widespread application (196S) study of variation in impac t, related to of similar field techniques increases the ability amc:)unt of use, on canoe campsites. This to develop broad generalizations and to under apprc^ach, though more time-consuming than stand the causes of variability. the simple descriptive survey, has the advan Each of these re.search designs has inher tage cjf providing an estimate* of the extent to ent strengths and weaknesses. The most appro- which conditions rellect rec reatiotial use*. priatc* approach to take will depend on the 46 D.N. Cole

goals of the study. Maximum insight can be either linear travel rcjutes, osLjally trails, or gained byutilizing several approaches simulta nodes of concentrated rise, osoally cam[asites neously. For example, Marion and Cole (1996) but also picnic sites and viewpoints. The other combined; (i) descriptive field surveys ofcamp tradition has been tf) stody the etiects ot tram sites, stratified according to amount of use and pling, which occurs on trails and campsites but vegetation type, along with measures taken on also away from these places ot concentrated

adjacent controls; (ii) natural experiments on use. previously undisturbed sites, before and after Trampling has at least three eltects: abra being opened for camping; (iii) natural experi sion ofvegetation, abrasion ot organic soil hori ments on established campsites, before and zons and compaction ot soil (Fig. 4. 5i. Plants after being closed to use, as well as before and can be bruised, crushed, sheered ott cmd even after management actions designed to reduce uprooted by trampling. Tram[Dling ettects in- campsite size; and (iv) trampling experiments. clucJe reductions in plant height, stem length Progress in recreation ecology is ham and leaf area, as well as in the numl;)er ot [plants pered by minimal attention given to conceptual thatflower, the number ot tlower heads [oer plant and theoretical development. Early exceptions and seed prcjcluction (Liddle, 1*^19/). Reduced include Liddle's (1975a,b) conceptual model of height and leaf area decrease thephotosynthetic trampling processes and his hypothesis that area of plants, resulting in de[)leted carbohy trampling tolerance is related to primary pro drate reserves (FHartley, 1999). These changes ductivity. Cole's (1992) simplified model of typically result in reductions itn plant vigour and campsites represents one of the few attempts to reproduction. Many plants are killed i^y tram use analytical models to build foundational pling. At moderate levels ot tram[)ling, however, concepts regarding how various factors operate some species increase in abundance, otten as a 'u etermining impact magnitude. Rigorous result of decreased competition or a change in ana yses of the efficiency of impact assessments microhabitat. Generally, where tramfiling is ^'^'^ough Leung and Marion intense, plant cover and hiomass are low, most 9c) is a notable exception. plants are short, species richness is reduced and speciescompcjsiticjn has shitted. Trampling compacts soils, reducing poros Research Results ity, particularly the volume ot macro[3ores Descriptive information about recreational (Monti and Mackintosh, 1979). This r(»duces the impacts can bedivided into information about water-holding capacity ot soil, except in some the nature and magnitude of impacts caused by coarse-textured soils, (aimi^action reduces • erent recreational activities, spatial aspects water infiltration rates, leading to increased 0 impacts, and temporal patterns of impact. runoff and erosion potential. These physical 1here is also an extensive body of information soil changes alter soil chemistry and biota, aDout use and environmental characteristics although such changes are poorly understood. hat influence the nature and magnitude of Compactedsoils can also inhibit seed germina tion and plant growth. Alessa and Earnhart impacts. This knowledge provides the basis for (2000) have shown that plants in compacted insight into management actions that might soils may be less able to utilize available nritri- effectively control impacts. Finally, a substan ents because they grow lewer lateral roots and tial amount of work has developed regarding root hairs and because cytoplasmit streaming the effectiveness of impact management tech within root hairs is reduced. Soil tomfiac tion niques, as well as efficient ways to monitor effects are exacerbated l)y abrasion and loss ot impacts. organic soil horizons, which shiekl underlying mineral soil horizons from excessive compac tion and erosion. The nature and magnitude of impacts Loss of organic litter direc tly atlec ts plant and animal populations, both above and below Much of the research into hikingand camping the grcjund. Since certain [dant spec ies germi impacts on soil and vegetation is focused on nate mcjst frec|uently on organic soil surtac es. Impacts of Hiking and Camping on Soils and Vegetation 47

Trampling

Abrasion of Abrasion of Compaction vegetation organic matter of soil

Reduction in Reduction in air and water litter cover permeability

Increase in Cfiange in runoff and soil biota erosion

Reduction in Reduction in plant plant vigour reproduction

Y Y Y

Change in Reduction in species vegetative

composition cover

Fig. 4.3. A conceptual model of trampling impacts. Note tfie numerous reciprocal and cyclic relationships.

loss of liller can cause s[)(h i(>s composition to impacts. Numerous studies have quantified the shift towards s|)ecies that j^erminate most fre- magnitude of soil and vegetation impact on c|uently on mineral soil. Loss of organic matter campsites. The data in Table 4.1 are typical. from the soil typically reduces the water- They describe vegetation and soil conditions holding capac ity ol thc> soil and has an adverse on 29 paired canoe-accessible campsites and effect on soil microhial [lopiil.itions, which undisturbed control sites in low-elevation ripar depend on soil organic matter and root e\u- ian forests in the eastern USA (Marion and dates from ahove-groimd plants tor their Cole, 199()). On mcpst camfpsites, most of the energy. Z.ihinski .ind Ciannon (l')<)7) report vc^getation has been eliminated and the vegeta suhsttintial reductions in tht> funttional diver tion that remains consists primarily of grami- sity of mi( rohial populations on a hackcountry noids. Forbs dominate undisturbed control campsite. Microhial popukitions contrihute to sites. Organic horizons on campsites are only ecosystem func tioning h\' metal^olizing nutri alioLit one-third as thick as on controls; mineral ents, transforming soil organic matt(>r, [produc soil is exposed over most of the campsite. These ing phytohormones and contributing to soil mineral soils are compacted - exhibiting fcpod webs. incrcMsed bulk density and penetration resis The imp.u Is ol cam|)ing inc ludc^ all the tance. Substantial numbers ol trees have been effects of tr.impling, as vvc>ll ,is some unir|uc> damaged (c cit branches or scarred trunks) or 48 D.N. Cole

Table 4.1. Vegetation and soil conditions on 29 campsites and undisturbed control sites at Delaware Water Gap National Recreation Area, 1986 (from Marion and Cole, 1996).

Campsite Control

Impact parameter Mean Range Mean Range P

Ground vegetation cover (%) 15 0-63 72 1-95 0.001 Floristic dissimilarity (%) 75 23-100 Not applicable Graminoid cover (%) 58 0-100 26 0-92 0.023 Forb cover (%) 23 0-78 59 5-100 0.001 Mineral soil cover (%) 61 21-94 1 0-15 0.001 Organic horizon thickness (cm) 0.5 0-1.4 1.5 0.2-3.1 0.002 Soil bulk density (g/cm^) 1.26 1.0-1.4 1.06 0.7-1.4 0.001 Soil penetration resistance (kPa)^ 275 137-382 49 0-226 0.001 Soil moisture (g/cm^) 18 8-32 17 8-31 0.710 Felled trees (%) 19 0-53 Not applicable Damaged trees (%) 77 25-100 Not applicable Tree reproduction (stems/ha) 936 0-6275 10,090 0-56,400 0.001 Non-vegetated area (m^) 181 0-696 0 0-15 0.001 Campsite area (m^) 269 51-731 Not applicable Shoreline disturbance (m) 9 0-20 Not applicable

^ 1 kPa=the pressure corresponding to 1.01971 x 10 ^ kg/cm^

felled, and tree reproduction has been dramat of trail construction and maintenance include ically reduced. Along with the felling of tree opening up tree and shrub canopies, the build saplings, lack oftree reproductionsuggeststhat ing of a barren, compacted trail tread that may overstorey trees will not be replaced on camp alter drainage patterns, and the creation of a siteswhen they eventually die. variety of new habitats, including cut slopes Camping also can cause off-site impacts. above the trail and fill below (Cole, 1981b). The most common off-site impacts are informal Except where hiking use is extremely high, it is trailing (between the campsite and water probably rare for the impacts of hiking on trails sources, other campsites or the main trail) and to exceed the impacts caused by trail construc impacts caused by the collection of wood to be tion. However, these rare cases of profound burned in campfires. Hall and Farrell (2001) hiking impact can be highly problematic. For documented 25-63% reductions (depending example, the deep, peaty soil of tracks in much on size class) in abundance of woody material of the Tasmanian Wilderness World FHeritage on and around campsites. Taylor (1997) found Area can be churned into deep quagmires by a that the density of saplings around campsites small number of hikers (Calais and Kirkpatrick, was reduced within an area that extended 45 m 1986; Whinam and Chilcott, 1999). on average from thecentre ofthecampsite. The Impacts adjacent to trails are similar to most pronounced off-site impacts are often those caused by trampling. Although trampling those associated with the confinement of adjacent to trails can reduce vegetation cover horses and other packanimals used to transport (Cole, 1978; Boucher ct a!., 1991), it is com people and gear (see Newsome ct a!., Chapter mon for vegetation cover to be greater adjacent 5, this volume). to trails than on undisturbed sites (Hall and Impacts on trails have also been studied. Kuss, 1989), presumably due to increased However, it is difficult to separate the impacts light, water and nutrients there. Organic matter of hiking on trails from the impacts associated can decrease and soil compaction increase with trail construction and maintenance, and (Adkison and Jackson, 1996). Vegetation com the impacts that would occur on trails in the position adjacent to trails is usually very differ absence of hiking (e.g. erosion by rainwater ent from undisturbed site controls. It c an be less channelled down a trail tread). Major impacts diverse (Boucher etai, 1991 i, but often is more Impacts of Hiking and Camping on Soils and Vegetation 49

diverse (Hall and Kuss, 198')i, [Dartially due to agement. For example, in Great Britain, Bay- the invasion of exotic species that use trails as field (1973)found that trailwidth was positively conduits for movement (Benninger-Truax ef a/., correlated with soil wetness, roughness and 1992). steepness, and Coleman (1981) found that trail Of more practical significance and con width was positively related to recreation use. cern is the impact of hiking on the constructed The most significant impacts of hiking on and maintained trail surl'ace. Constructed trails native soils and vegetation are probably those are barren and compacted by design. So, the associated with proliferation of user-created interest here is not impacts on native soil and trails along hiking routes where a trail tread is vegetation but impacts on the trail itself.This is never constructed. Lance etal. (1989), describe a concern because hikers can increase soil ero this process in Scotland, noting that trail devel sion from trails, either by detaching or trans opment usually starts with formation of a single porting soil particles. Two recent experimental track. As this path widens and erodes, secon studies provide insight into the process by dary paths are created. These widen and merge which this occurs. They show that sediment with other paths, ultimately creating a braided, yield and trail erosion is detachment-limited eroding web (Fig. 4.4). On the tallest peaks in rather than transport-limited (Wilson and Colorado, user-created trails to the summits Seney, 1994; DeLuca ct a/., 1998). Trail use have eroded so severely that they are now loosens soil particles, making them easier to being replaced by constructed trails. Restora detach and, therefore, available to be trans tion of abandoned sections of user-created trail, ported by such erosive agents as running water. which are often steep and eroding, is difficult Most trail-impact studies document trail (Ebersole ef a/., 2002). characteristics, such as width and depth, with out regard for the comfjlex factors (of use, envi ronment and management) that combine to Spatial patterns of impact influence these characteristics. Bayfield and Lloyd (1973) developed survey techniques for Most studies of impact report the intensity of periodically assessing trail width and depth, as particular types of impact - the amount of well as censLising the presence or absence of impact per unit area (e.g. the campsitelost 50% 'detracting' features, such as rutting and bad of its vegetation cover).Assessments of magni drainage. Coleman (1977) developed a tech tude of impact must also consider the area over nique for measuring trail cross-sectional area. which this impact occurs. The magnitude of a More recent assessments of trail conditions, in 50% cover loss on a 1000 m- campsite is twice such places as Guadalupe Mountains National that of a 50% cover loss on a 500 m- campsite Park (Fish et dl., 1981), the Selway-Bitterrcwt - although the intensity of impact is the same. Wilderness, (Cole, 1983) and Great Smoky Magnitude of impact (sometimes referred to as Mountains National Park (Leung and Marion, aggregate impact) is minimized when both the 1999b), are largely extensions of this early area of impact and the intensity of impact per work. These studies provide descriptive statis unit area are minimized (Cole, 1981a). Certain tics (means and ranges) tor such metrics as trail impact parameters only describe impact inten width and depth, as well as frequency and sity (e.g. vegetation cover loss), while others extent of trail [iroblems (Bayfield's 'detracting' only describe area of impact (e.g. campsite features). For example, mean trail width and area). A few parameters describe both. For depth were 115 cm and 10cm, respectively, on example, the area of vegetation losson a camp trails in the Selway-Bilterroot Wilderness (Cc^le, site (Cole, 1989b) expresses vegetation loss, in 1991). On trails in Great Smoky Mountains m-', as the product of campsite area and the dif National Park (Leung and Marion, 1999b) there ference between vegetationcoveron the camp were 470 occurrent es of multi|;)le tread. A total site and an adjacent control site. This metric- of 10.3 km of trail (1.8"/., ot the trail system) had makes it possible to comparethe magnitude ol multiple treads. These studies typically search vegetation impact on sites that vary greatly in for correlations between trail conditions and size (e.g. Marion and Farrell, 2002). characteristics ot use, environtnent and man Spatial aspects of impact have received 50 D.N. Cole

'-" • - ^ ' ' '

V•fc;r.<-r-w; -^V...:

• .^.i«5*2i*. J.V : ' I

Fig. 4.4. Trail braiding is a common type of trail impact in certain environments.

little attention, beyond recognition that assess small at the scale of 10,000ha. They may be ments of the magnitude of impact must con regularly distributed at a lOha scale but sider the area that has been impacted, as well clumped at the scale of 10,000ha. What this as the intensity of impact. In addition to the suggests is that any quantification ol im|)acts is intensity and aggregate area (magnitude) of only valid at the chosen scale of analysis. impact, other potentially important descriptors Although generally ignored, spatial des of impact include the sizeof impacts and the criptors of impact and scaling issues are impor spatial distribution (pattern) ofimpacts. Given a tant considerations, particularly in assessing constantaggregate area of impact, there may he how much of a problem impacts are, and in many small impacts or a few large impacts. devising strategies for managing them. Cole Theoretically, these impacts can he distributed (1981 b) noted that hiking and camping impacts in a pattern that is either more clumped (aggre on soil and vegetation, while severe when gated orunderdispersed) or more regular (over- measured at small scales, are minimal at large dispersed) than a random pattern. In reality, spatial scales. This suggests that while recrea spatial impact patterns are almost always more tion impacts can be serious for individual clumped than random. Campsites are clustered plants and animals, and perhaps localized rare in campgrounds or around lakes and in places populations, they are generally of little signiti- accessed by trails. Hiking impacts are concen cance to landscape integrity or regional biotic trated along trail corridors, with little impact off diversity. Moreover, unless much of a popula trail. tion is impacted by a single im[aacted site, tbe Quantitative descriptions of impact vary intensity, size and distribution ol im[)acts are with the spatial scale of analysis that is not relevant to the significance ot imfaacts selected. For example, vegetation loss may he assessed at large spatial scales. II animal popu 1007o at the centre of a campsite hut only 507o lations are considered, however, spatial [)at- when the entire campsite is surveyed. At the terns in which imfjacts are clustered, leaving scale of a lake basin, vegetation loss associated large expanses undisturbed, might l:>e th(> ideal. with camping might amount to only 1 or 27o Recreation impacts on soil arid vegetation and, at the scale of the park or wilderness, less are highly significant at the stale of human per than ]"/(, of the vegetation is likely to he lost ception - the scale humans can re.idily observe. (Cole, 1981h). Impacts might he considered Studies r)f wilderness campers show th«it most few and large at a 10 ha scale hut many and campers view small areas of impac t as 'posi- Impacts of Hiking and Camping on Soils and Vegetation 51

Effective closure of campsites Low resilience environment

Several years after initial use

o High resilience E < environment

Campsite is first used

Time

Fig. 4.5. The typical life history of a campsite, from initial use through a period of closure and recovery. five', 'pretty natural, healthy' (Farrell ct a/., ral patterns of impact, much as the tendency to 2001), liecause ihey make the site lunctlon well conduct studies at just one spatial scale leaves as a temporary dwelling lor humans. Perhaps us with little insight into spatial patterns. from the human perspective, many small Available studies suggest that individual camp impacts are [3referal)le to a fcnv large impacts, sites have a typical 'life history', movingsucces because small imfiacts are perceived as sively through stages of development, dynamic 'healthy' dwelling sites, while large impacted equilibrium and recover)' (Fig. 4.5). Impact areas (several hectares or more) suggest abuse, occurs rapidly during the development phase, damage and unhealthy conditions. Moreover, shortly after a campsite is first used. For exam dispersal ol im|:)acts at this scale provides more ple, on newly established canoe campsites, solitude and privacy lor tourisls. This line of most of the impact that occurred over the 6 thinking leads to the conclusion that, when years following creation of the campsite impacts cjn soils, v(>getaiion, animals and occurred during the first year of use (Marion and humans are all considered, they are least prob Cole, 1996). Impact did increase over the first 3 lematic when; (i) aggregate^ impact (intensity in years, but at a decelerating rate. This phase is combination with area) is minimized; and (ii) followed by a more stable phase in which impacts are concentrated al the site scale, dis impacts change little unless there are dramatic persed at intermediate scales (within a destina- changes in amount of use. For example, on ticjn area such as a lake basin) and c luslered at long-established campsites in the Eagle Cap larger scales (within a [xirk or wilderness) Wilderness, mean vegetation cover was 15% in (Hammitt and dole, 1008). Although little atten 1979, 127n in 1984 and 19% in 1990 (Cole and tion has l)een devoted to these spatial issues, Flail, 1992). Vegetation cover on these camp Leung and Marion (1 OOOd) suggest some Sfiatial sites might be expected to fluctuate between strategies lor managing impacts. about 10"/o and 20%, as long as use character istics are relatively stable. These patterns are rel atively consistent across diverse ecosystem Temporal patterns of Impact types and typesof recreation, although impacts occur more rapidly (the development phase is The tendenc y to sludv impac Is at on(> point in shorter) as amount ot use increases and site dur- time has contributed to a lac k ot data on tem|-)o- abilitv decreases. Moreover, aberrant behaviour 52 D.N. Cole

Type and Frequency Season Environmental Spatial distribution befiaviour of use of use conditions of use of use

Intensity of impact Area of impact

Total impact

Fig. 4.6. Factors that influence the intensity and area of impact and, therefore, the total amount of impact.

(e.g. someone cutting down a tree) can cause Temporal patterns on trails and hiking dramatic spikes in impact at any time. routes are likely to be similar, though they have The recovery phase is almost invariably seldom been studied. Trail impacts occur rap longer than the development phase, because idly; most segments on established trail systems deterioration occurs more rapidly than recov are generally stable (Fish ct a/., 1981; Cole, ery. Recovery rates also varygreatly with kinds 1991); and recovery of closed trails is typically of impact, magnitude of impact and environ slow, except where it is assisted (Eagen et al., ment. Variation in the resilience of different 2000). However, trail segments that are poorly ecosystem types is pronounced. Hartley (1999) located or inadequately designed and main reports residual effects of trampling after 30 tained may deteriorate substantially. At large years, in alpine meadows in Glacier National spatial scales, impacts have increased over time Park, while most evidence of camping on due to: (i) lack of recovery on re-routed trail closed riparian campsites disappeared within 6 segments; and (ii) the pioneering of routes into years (Marion and Cole, 1996). Cole and Monz trailless places. This latter trend can be particu (2002) report that an alpine grassland trampled larly problematic because development of a 1000 times recovered more rapidly than a trail makes access easier, which can lead to a neighbouring forest, withan understorey of low cycle of ever-increasing use and impact. shrubs, that was trampled just 75 times. Given the same environmental setting, sites that receive more use and that are more heavily Factors that influence magnitude of impacted will take longerto recover. impact Temporal patterns at larger spatial scales have generally been ignored. They are particu The types of research that have probably been larly important, however, because impacts tend most useful to management are studies of the to proliferate and spread across the landscape factors that influence the magnitude ot impacts where use distribution is not tightly controlled. -why impacts are minor in some situations and Forexample, in two drainages in the Eagle Cap severe in others. The principal factcirs that influ Wilderness, the number of campsites increased ence intensity of impact (Fig. 4.6) are: (i) fre from 336 in 1975 to 748 in 1990 (Cole, 1993), quency of use; (ii) type and behaviour of use; even though the condition of most of the sites (iii) season of use; and (iv) environmental con that existed in 1975 changed little between ditions, while area of impact is primarily a 1975 and 1990. Site proliferation occurs result of the spatial distribution of recreation because, as use shifts across the landscape, use (Cole, 1981a, 1987). An understanding of new campsites appear more rapidly than old each of these influential varial")les suggests campsites disappear. strategies for managing the inqiac ts ot hiking Impacts of Hiking and Camping on Soils and Vegetation 53

pacts of hikers with those of groups who use horses or llamas for transport. Generally, these studies have found that horses cause more impact than hikers or llamas, which cause equivalent levels of impact (Cole and Spildie, 1998; DeLuca etal., 1998). Recreationecology research has provided the scientific foundation for minimum-impact educational programmes (Cole, 1989c). These programmes teach tech niques of trip planning, route selection, hiking behaviour, campsite selection and camping Amount of use behaviour that minimize the per capita impacts Fig. 4.7. The relationship between amount of use of use. and amount of impact is curvilinear (asymptotic). Season of use is a less critical factor for hikers than it is for horses and heavy pack ani mals that can cause severe damage to trailsand and camping on soils and vegetation (Cole et meadows when soils are water-saturated and al., 1987; Marion and Leung, Chapter 13, this plants are growing rapidly. During seasons volume). when snow banksare melting, hikers also need The relationship between frequency of use to avoid walking offtrail andon water-saturated and intensity of impact is generally asymptotic soils. (Fig. 4.7). At first, small increases in use fre A substantial body of research has devel quency cause pronounced increases in impact; oped regarding characteristics that make differ however, the rate of increase in impact de ent environments more or less durable as creases as use intensity increases. Where use is campsites or as trail locations. Experimental light, sites that receive even small differences in applications of both trampling (e.g. Bayfield, amount of impact can have very different 1979; Cole, 1995b) and camping (Cole, 1995c) impact levels. However, where use is heavy, have been particularly insightful in building sites that receive substantiallydifferent amounts this knowledge. Field surveys of trails and of use may have similar impact levels. Frissell campsites that develop correlations between and Duncan (1 965), the first researchers to doc impact parameters and environmental vari ument this relationship in a field situation, con ables have also been helpful (e.g. Leung and cluded that 'if any use is to be allowed in the Marion, 1999a,b). Experimental studies show wilderness areas, some immediate loss of the that some vegetation types can tolerate more natural vegetation will have to be tolerated' (p. than 30 times as much use as others, with no 258). Similar results have been found in numer more damage (Cole, 1995a). ous field surveys of recreation sites and in Experimental studies suggest that there is experimental studies. The further implication of an important difference between a site's resis this relationship is that the magnitude of tance (its ability to tolerate use without being impacts can usual ly be minimized by encourag damaged) and its resilience (its ability to ing the repetitive use of as small a number of recover from damage). Cole (1995b) has sites as possible (i.e. concentrating use) (Cole, shown, for groundcover plants, that resistance 1981a). This strategy involves accepting a slight decreases with erectness and that broadleaved increase in the intensity ot impact to realize the herbs are typically less resistant than grass-like benefits of a large decrease in the area of plants and shrubs. Herbs growing in shade are impact. particularly intolerant of trampling because The type and behaviour of use can also adaptations to shading - possession of large, have a profound elfect on both the type and thin leaves and tall stems - make these plants magnitude of impact. For example, campers vulnerable when trampled. This explains the whfj build fires cause both more and different common finding thattrampling offorested sites types of impact than campers who do not huild generally results in more rapid loss of vegeta fires. Several studies have compared the im tion than trampling of open woodlands or 54 DM Cole

m

' v-""v:* ',-v7r--r', '^' •*

-;^d

Fig. 4.8.The areaofvegetation loss on this campsite is small, due to the durability of the graminoid vegetation cover.

meadows. Low shrubs, such as heather, are rel nelled, with more force, clown the trail tread. atively resistant to trampling stress, but their Trail problems are also common where soils are resilience is low. Once damaged, they recover fine-textured, stone-tree and hrjmogeneous, or slowly. Grass-like plants are most tolerant of highly organic and where soils are poorly trampling. drained or have high water tables. Trails also At the risk ofovergeneralizing about a very tend to widen where the grcjunci surface is wet complex subject (refer to reviews in Cole, or rough (Bayfield, 1973). 1987; Liddle, 1997; Hammitt and Cole, 1998; and Leung and Marion, 2000, for further details), a few conclusions about site durability Management and monitoring seem warranted. Characteristics of durable campsites and other nodes of concentrated use Management and mcjnitcjring ol trails and include: (i) either lack of groundcover vegeta campsites are covered in detail in Leung and tion or presence of resistant vegetation (Fig. Marion (Chapter 14 this volume). The scientific 4.8); (ii) an open, rather than closed, tree foundation for knowledge about etiective man canopy; (iii) thick organic soil horizons; or (iv) agement strategies was derived from hundreds a relatively flat but well-drained site. Marion of studies of the nature and magnitude of and Farrell (2002) also note the importance of impacts, and how they are influenced by char designing campsites to confine impacts to a acteristics of use and the environment. Along small area, in the absence of natural features with the experiential knowledge^ developed such as rocky terrain that serve this purpose. from decades of implementing ret reation man Leungand Marion (1996) provide a useful agement programmes, a wide array ot etiective overview of knowledge regarding how environ management strategies has evolved (Hammitt mental characteristics influence trail condition. and Cole, 1998). Similarly, decades ot recrea- Terrain and topography have a major influence ticjn ecology research, developing methods ot on trail conditions. Steep trail slopes, steep side measuring impact, have caintributed to tht^ slopes and trail alignments in which the trail campsite and trail monitoring methods em directly ascends slopes all tend to be more ployed today (Cole, 1983, 1989a; M.trion, degraded, usually because more water is chan 1991; Leung and Marion, H)99b). Impacts of Hiking and Camping on Soils and Vegetation 55

Conclusions and Future Directions as a result of new places being disturbed than from the deterioration of places that have been Although the field of recreation ecology is only disturbed for a long time. Thisalso emphasizes about 30 years old, somewhere around 1000 the need to be attentive to relatively pristine studies have been conducted. A majority of places and to focus attention on the spatial dis these have focused on the impacts of hiking tribution of use. It suggests that periodic inven and camping on recreation and soils. Specific tories of all impacted sites is often more details about the nature, magnitude and spatial important than monitoring change on a sample aspects of impact vary with the context of every of established sites. situation (with amount and type of use, envi 4. Magnitude of impact is a function of fre ronment, management, etc.). In addition, the quency of use, the type and behaviour of use, management objectives of every park, wilder season of use, environmental conditions, and ness or other tourist destination also vary. the spatial distribution of use. Therefore, the Therefore, in every place where recreation primary management tools involve manipula impacts are a concern, it is worthwhile to have tion of these factors. recreation ecology studies conducted in that 5. The relationship between amount of use area, so results can be interpreted in reference and amount of impact is usually curvilinear to the specific context and management objec (asymptotic). This has numerous management tives of the area. However, in the absence of implications and is also fundamental to many site-specific studies and intbrmation, much minimum impact educational messages. Itsug insight can be gleaned from generalizations gests that it is best to concentrate use and suggested by the recreation ecology literature. impact in popular places and to disperse use Since the late 1 970s, there have been sev and impact in relatively pristine places. eral attempts to synthesize the recreation ecol ogy literature. Each attempt, including this one, New insights into recreation ecology have is somewhat unique but there is substantial been generated as researchers have adopted consensus as well. The lollowing five general multiple methodologies and expanded both the izations are among the most important and temporal and spatial scales of analyses. generally agreed upon. However, further progress is hampered by a lack of theory and conceptual thinking. Now 1. Impact is inevitable with repetitive use. that the field is 30 years old, the time seems ripe Numerous studies have shown that even very for conceptual and theoretical work that can low levels of repetitive use cause impact. build a framework for organizing the knowl Therefore, avoiding impact is not an option edge gained from the multitudeof idiosyncratic unless all recreation use is curtailed. Managers field studies that have been conducted. must decide on acceptable levels of impact and Two critical gaps in knowledge also limit then implement actions capable of keeping use maturation of the field. First, research needs to to these levels. move beyond the easily observable and mea 2. Impact occurs rapidly, while recovery surable effects of recreation. In particular, we occurs more slowly. This underscores the need to better understand relationships be importance of proactive management, since it tween the physical, chemical and biological is much easier to avoid im[oact than to restore effects of recreation on soil, and how these soil impacted sites. It also suggests that relatively impacts affect, and are affected by, plants. In the pristine places should receive substantial absence of such knowledge, attempts to restore management attention, in contrast to the damaged sites often fail. Plants are placed in common situation of focusing most resources soil that has not held plants for a half-century in heavily used and impactcb [daces. Finally, and the plants die (Moritsch and Muir, 1993). it indicates that rest-rotation of sites (periodi Soil amendments are needed before plants can cally clcjsing damaged sites, to allow recovery, survive (Cole and Spildie, 2000; Zabinski et a/., before re-opening them to use) is likely to be 2002). Restoration has been called the acid test ineffective. of our ecological knowledge (Jordan ct a/., 3. In many situations, im|)act increases more 1987) because our ability to restore ecosystems 56 D.N. Cole

will be dependent on the depth of our under Scottish hill paths. Journal of Applied Ecology standing and insight into howecosystemswork. 10, 639-648. By this definition, our understanding of recrea Bayfield, N.G. (1979) Recovery f)f four montane tion ecology is still wanting. heath communities on Cairngorm, Sccjtland, from disturbance by trampling. Hiological The lack of attention that recreation ecolo- Conservation 1 5, 1 65-1 79. gists have given to the spatial aspects of recre Bayfield, N.G. and Lloyd, K.j. (1973) An a|3proach to ationimpacts isalso problematic. Impacts have assessing the impact of use on a long distance almost always been evaluated at the meso- or footpath —the Pennine Way. Recreation News site-scale. Populations and communities of Supplement 1973, 11-17. plants and soil pedons have been the primary Benninger-Truax, M., Vankat, j.L. and Shaefer, K.L. unit of analysis. We have generally done a good (1992)Trail corridors as habitat and conduits for job of describing impacts that occur at the movement of plant species in Rocky Mcauntain human scale. As mentioned above, lack of National Park, Colorado. Landscapi' Ecolrygyh, research atsmaller scales hampers ourability to 269-278. restore damaged sites. Lack ofresearch at larger Boucher, D.H., Aviles, ]., Chepote, R., 19ominguez- spatial scales - regarding how landscapes and Gil, O.E. and Vilchez, B. (1991) Recovery of regions are impacted by recreation - limits our trailsicle vegetation from trampling in a tropical insight into the significance of recreation rain forest. Environmental Management 15, 257-262. impacts. How do we answer the 'so what' ques Buckley, R.C. and Pannell, ). (1990) Environmental tions? Hiking and camping impacts on soil and impacts of tourism and recreation in national vegetation are generally severe but localized parks and conservation reserves. Journal ot disturbances. Evaluations of these impacts at Tourism StucJies 1, 24-32. larger spatial scales would result in wiser Calais, S.S. and Kirkpatrick, J.B. (1986) Impact judgements about how much of a problem of trampling on natural ecosystc>ms in the these impacts are, and the most appropriate Cradle Mountain-Lake St Clair National Park. balance between impacts and access for recre Australian Geographer 17, 6-1 5. ation and tourism. Cole, D.N. (1978) Estimating the susceptibility of wildland vegetation to trailsicle alteration. Journal ofApplied Ecology 15, 281-286. Cole, D.N. (1981a) Managing ecological impacts at References wilcJerness campsites: an evaluation ot tech- nicjues. Journal of Forestry79, 86-89. Adkison, G.P. and Jackson, M.T. (1996) Changes in Cole, D.N. (1981 b) Vegetational changes assoc iated ground-layer vegetation cover near trails in with recreational use and fire sup[iression in the Midwestern U.S. forests. Natural Areas Journal Eagle Cap WilcJerness, Oregon: some manage 16, 14-23. ment implications. Biological Cr^nservation 20, Alessa, L. and Earnhart, C.G. (2000) Effects of soil 247-270. compaction on root and root hair morphology; Cole, D.N. (1983) Assessing and Monitoring Back- implications for campsite rehabilitation. In: countryTrail Conditions. Research Pafier INT-303. Cole, D.N., McCool, S.F., Borrie, W.T. and US Department of Agriculture, Forest Service, O'Lough Iin, ]. (comps) Wilderness Science ina Intermountain Research Station, Ogden, Utah. Time ofChange Conference. Vol. 5. Wilderness Cole, D.N. (1986) Recreational impacts on back- Ecosystems, Threats and Management Pro country campsites in Grand Canyon National ceedings RMRS-P-15-VOL-5. U.S. Department Park, Arizona, USA. Environmental Manage of Agriculture, Forest Service, Rocky Mountain ment I 0, 651-659. Research Station, Ogden, Utah, pp. 99-104. Cole, D.N. (1987) Research on soil and vegetation Bates, G.Ft. (1935) Vegetation of footpaths, side in wilcJerness: a state-ol-knowleclge revicwv. walks, cart-tracks, and gateways, journal of In: Lucas, R.C. (comp.) Proceedings National Ecology 23, 470-487. Wilderness Researc h Conference: Issues, State- Bayfield, N.G. (1971) Some effects of walking and of-knowledge. Future Hirer tions. Ciener.il Icx h- skiing on vegetation at Cairngorm. In: Duffey, E. nical Report INT-22(). US (department of and Watt, A.S. (eds) The Scientific Management Agriculture, Forest Service, Intermountain of Plant andAnimal Communities for Conserva Research Station, Ogdc^n, Utah, |ip. M5-1 77. tion. Blackwell,Oxford, UK, pp. 469-485. Ode, D.N. (1989a) Wilderness Campsite Ntonitoring Bayfield, N.G. (1973) Use and deterioratiran of some Methods: a Sourcehook. Gener.il Technical Impacts of Hiking and Camping on Soils and Vegetation 57

Report INT-25'^). US |])e[iartnient ol Agriculture, Cole, D.N. and Monz, C.A. (2002) Trampling distur Forest Service. Intermountain Research Station, bance of high-elevation vegetation. Wind River Ogden, Utah. Mountains, Wyoming, U.S.A. Arctic, Antarctic, Cole, D.N. (1989b) Area ol VogctKition Loss: a New and Alpine Research 34, 365-376. Index of Campsite Impact. Research Note INT- Cole, D.N., Petersen, M.E. and Lucas, R.C. (1987) 389. US De|)artment ol Agriculture, Forest Managing Wilderness Recreation Use: Com Service, Intermountain Research Station, mon Problems and Potential Solutions. General Ogden, Utah. Technical Report INT-259. US Department Cole, D.N. (1989c) Low-impact Recreational of Agriculture, Forest Ser\'ice, Intermountain Practices tor Wilderness and Backcountrw Research Station, Ogden, Utah. General Technical Report INT-2b.S. US Cole, D.N.and Spildie, D.R. (1998) Hiker, horse, and Department erf Agriculture, Forest Service, llama trampling effects on native vegetation in Intermountain Research Station, Ogden, Utah. Montana, USA. Journal of Environmental Cole, D.N. (1991) Changes on Trails in the Selway- Management 53, 61-71. Bittcrroot Wilderness, Montana, 1978-89. Cole, D.N. and Spildie, D.R. (2000) Soil amendments Research Paper INT-450. US Department ot and planting techniques: campsite restoration in Agriculture, Forest Service, Intermountain the Eagle Cap Wilderness, Oregon. In: Cole, Research Station, Ogden, Utah. D.N., McCool, S.E., Borrie,W.T. andO'Loughlin, Cole, D.N. (1992) Modeling wilderness campsites; ]. (comps) Wilderness Science in a Time of factors that influence amount of impact. Change Conference. Vol. 5. Wilderness Eco Environmental Management 16, 255-264. systems, Threats and Management. Proceedings Cole, D.N. (1993) Campsites in Three Western RMRS-P-15-VOL-5. US Department of Agri Wildernesses: Proliferation and Changes in culture, Forest Service, Rocky Mountain Condition over 12 to 18 years. Research Paper Research Station, Ogden, Utah, pp. 181-187. INT-463. US Department of Agriculture, Forest Coleman, R.A.(1977) Simple techniques for monitor Service, Intermountain Research Station, ing footpath erosion in mountain areas of north Ogden, Utah, USA. west England. Environmental Conservation 4, Cole, D.N. (1995a) Experimental tram|)ling of vege 145-148. tation. I. Relationshi[) between trampling inten Coleman, R. (1981) Footpath erosion in the English sity and vegetation response, lournal ofApplied Lakes District. Applied Geography 1, 121-131. Ecology 32, 203-2 14. Cordell, H.K. and Super, G.R. (2000) Trends in Cole, D.N. (1995b) Experimental trampling of vege American's outdoor recreation. In: Gartner, tation. II. Predictors of resistance and resilience. W.C. and Lime, D.W. (eds) Trends in Outdoor Journal ofApplied Ecology 32, 21 5-224. Recreation, Leisure and Tourism. CAB Cole, D.N. (1995c) Disturbance of natural vegetation International, Wallingford, UK, pp. 133-144. by camping; experimental applications of low DeLuca, T.H., Patterson, W.A., Freimund, W.A. and level stress. Environmental Management 19, Cole, D.N. (1998) Influence of llamas, horses, 405-416. and hikers on soil erosion from established rec Cole, D.N. (1996) Wilderness recreation in the reation trails in western Montana, USA. United States-trends in use, users, and impacts. Environmental Management 22, 255-262. International Journal of Wilderness 2, 14-18. Eagen, S., Newman, P., Fritzke, S. and Johnson, L. Cole, D.N. (2002) Ecological imf^acts of wilderness (2000) Restoration of multiple-rut trails in recreation and their management. In: Hendee, Tuolumne Meadows ofYosemite National Fbrk. J.P. and [i)awson, C.P. (eds) Wilderness In: Cole, D.N., McCool, S.F., Borrie, W.T. and Management: Stewardship and Protection of O'LoughIin, j. (comps) Wilderness Science in Resources and Values. Fulcrum Publishing, Time of Change Conference.Vol. 5. Wilderness Gfdden, Colorado, USA, [ip. 413-459. Ecosystems, Threats and Management. Pro Cole, D.N. and Baytield, N.G. (1993) Recreational ceedings RMRS-P-15-VOL-5. US Department of trampling ot vegetation: standard experimen Agriculture, Forest Service, Rocky Mountain tal procedures. Biologiial Cc^nservation 6 1, Research Station, Ogden, Utah, pp. 188-192. 209-2 1 5. Ebersole, |.|., Bay, R.F. and Conlin, D. (2002) Cole, D.N. and Hall, I.E. (1992) Trends in Campsite Restoring high-alpine social trails on the Condition: Lagle Cap Wilderness, R(^b Marshall Colorado Fourteeners. In: Perrow, M.R. and Wilderness and Crand Canycni National Park. Davy, A.), (eds) Handbook ot Ecological Research Paper INT-451. US Department ot Restoration. Vol. 2, Restoration in Practice. Agri( ulture. Forest Servir e, Intermountain Cambridge University Press, Cambridge, UK, Researc h Station, ()gden, Utah. pp. 389-391. 58 D.N. Cole

Farrell, T.A. and Marion, J.L. (2001a) Identifying and Aleppo pine forests on Mount Carmel, Israel. assessing ecotourism visitor impacts at eight Israel Journal of Plant Sc iem cs 49, 49-56. protected areas in Costa Rica and Belize. Lance, A.N., Baugh, 1.(9. and Lovc», J.A. (1989) Environmental Conservation 28, 215-225. Continued footpath widening in the Cairngorm Farrell,T.A. and Marion, J.L. (2001 bJTrail impacts and Mountains, Scf)tland. Biological Conservation trail impact management related to visitation at 49, 201-214. Torres del F^ine National F^rk, Chile. Leisure Lemauviel, S. and Roze, F. (200 3) Kes[oonse of three 26, 31-59. plant communities to tramfding in a sand dune Farrell, T., Hall, T.E. and White, D.D. (2001) system in Brittany (France). Environmental Wilderness campers' perception and evaluation Management 31, 22 7-2 35. ofcampsite impacts. Journal ofLeisure Research Leung, Y. and Marion, J.L. (1996) Frail degradation as 33, 229-250. influenced hy environmental factors: a state-of- Fish, E.B., Brothers, G.L. and Lewis, R.B. (1981) knowlecige review. Journal ot Soil and Water Erosional impacts of trails in Guadalupe Conservation 51, 1 30-1 3 6. Mountains National Park. Landscape Planning Leung, Y. and Marif)n, J.L. (1999a) Characterizing 8, 387-398. backcountry camping imfiacts in Great Smoky Frissell, S.S. (1978) judging recreational impacts on Mountains National Park, USA. Journal ot wilderness campsites. Journal of Forestry 76, Environmental Management 57, 193-203. 481-483. Leung, Y. and Marion, J.L. (1 999h)Assessing trail con Frissell, S.S. and Duncan, D.P. (1965) Campsite prefer ditions in protected areas: a[)plicati(3n ofa prob ence and deterioration in the Quetico-Superior lem assessment method in Great Smoky canoecountry. Journal of Forestry 65, 256-260. Mountains National Park, USA. Environmental Garland, G.G. (1987) Rates of soil loss from moun Conservation 26, 270-270. tain footpaths: an experimental study in the Leung, Y. and Marion, J.L. (1999c) The inlluence of Drakensberg Mountains, South Africa. Applied sampling interval on the accuracy of trail impact Geography?, 41-54. assessment. Landscape and Urban Planning 43. Hall, C.N. and Kuss, F.R. (1989) Vegetation alteration 167-179. along trails in Shenandoah National Park, Leung, Y. and Marion, J.L. (1999d) S[:)atial strategies Virginia. Biological Conservation 48, 211-227. for managing visitor im[)acts in national parks. Hall, T.E. and Farrell, T.A. (2001) Fuelwood depletion Journal of Park and Recreation Administration at wilderness campsites: extent and potential 17, 20-38. ecological significance. Environmental Conser Leung, Y. and Marion, J.L. (2000) Recreation impact vation 2Q, 241-247. and management in wilderness: a state-ot- Hammitt, W.E. and Cole, D.H. (1998) Wildland knowledge review. In: Cole, D.N., McCool, S.F., Recreation: Ecology and Management, 2nd Borrie, W.T. and O'Loughlin, J. (comps) Wilder edn. John Wiley &Sons, New York. ness Science in a Time ot Change Conference. Hartley, E.A. (1999) Visitor impact at Logan Pass, Vol. 5. Wilderness Ecosystetns, Threats and Glacier National Ftark: a thirty-year vegetation Management. Proceedings RMRS-P-1 5-VOL-5. study. In: Harmon, D. (ed.) On the Frontiers of US Department of Agriculture, Forest Service, Conservation. George Wright Society, Hancock, Rocky Mountain Research Station, Ogden, Michigan, pp. 297-305. Utah, pp. 23-48. Hawkins, j.P. and Roberts, C.M. (1993) Effects of rec Leung, Y. and Neller, R.J. (1995) Trail degradation reational scuba diving on coral reefs: trampling along the PatSin Range: an example ot environ on reef-flat communities. Journal of Applied mental geomorphokjgy. Hong Kong Geologist Ecology30, 25-30. 1, 79-87. Jim, C.Y. (1987) Trampling impacts of recreationists Liddle, M.J. (1975a) A selective review ol the ecolog on picnic sites in a Hong Kong country park. ical effects of human trampling on natural eco Environmental Conservation 14, 117-127. systems. Biological Conservation 7, 17—36. Jordan, W.R., Gilpin, M.E. and Aber, J.D. (eels) (1987) Liddle, M.J. (1975b) A theoretical relationship Restoration Ecology. Cambridge University between the primary [jroduc tivity of vc^getation Press, Cambridge, UK. and its ability to tolerate Ir.impling. Biological Jusoff, K. (1989) Physical soil-properties associated Conservation 8, 2 51-255. with recreational use of a forested reserve area Liddle, M.J. (1997) Recreation Ecology. Chafiman

Liddle, M.J. and Kay, A.W. (I'587i Resistance, survi www.env.leeds.ac.uk/elgon/trampling. html val and recovers- ot Irani[:)led corals on the (verified 30 January 2003). Great Barrier RetM. Hiolopicjl Condonation A2, Rouphael, A.B. and Inglis, G.J. (2002) Increasedspa 1-18. tial and temporal variabilitc' in coral damage Liddle, M.J. and Thyer, N. (1988) Tram[3ling and tire caused by recreational scuba diving. Ecological in a subtropical dry sc lerophs-ll forest. En\ir(}n- Applications 12, 427-440. mental Condor\ati(yn 11. Scott, J.J. and Kirkpatrick, J.B. (1994) Effects of Marion, j.L. (1991) Do\ eloping a Natural Rodource human trampling on the sub-Antarctic vegeta Inventory and Monitoring Prc\yrani for Viditor tion of Macquarie Island. Polar Record 30, Impacts on Rccrcatiim Sitod: a Procedural 207-220. Manual. Natural Resources Report NPS/NRV'T/ Spildie, D.R„ Cole, D.N. and Walker, S.C. (2000) NRR-91/()8. US [^e[iartnient of Interior, Effectiveness of a confinementstrategy in reduc National Park Service, Denver, Colorado. ing pack stock impacts at campsites in the Marion, J.L. and Cole, U.N. ( I9<^)bi Spatial and tem Selway-Bitferroot Wilderness, Idaho. In: Cole, poral variation in soil and vegetation imf^actson D.N., McCool, 5.P., Borrie,W.T. and O'Loughlin, campsites. Ecological Applicationd b, 520-530. J. (comps) Wilderness Science in a Time of Marion, J.L. and Farrell, T.A. (2002) Management Change Conference. Vol. 5. Wilderness Eco- practices that conccMitrate visitor activities: svstems, Threats and Management. Proceedings camping im|)act management at Isle Royale RMRS-P-15-VOL-5. US Department of Agri National l^ark, LISA, journal of En\ ironmental culture, Forest Ser\'ice, Rocky Mountain Management 86, 201 -2 12. Research Station, Ogden, Utah, pp. 199-208. Marion, J.L. and Leung, Y. (2001) Trail rc^source Stankey, G.H., Cole, D.N., Lucas, R.C., Petersen, impacts and an examination of alternative M.E. and Frissell, S.S. (1985) The Limits of assessment technicjues. Journal of Park and Acceptable Change iLACi System for Recreation Administration 19, 17-17. Wilderness Planning. Research Paper INT-176. Meinecke, E.P. (1928) The Effect of E\cesdi\. e Tourist US Department of Agriculture, Forest Service, Travel on the California Redwood Parks. Cali Ogden, Utah. fornia 13e|)artmeMit of Natural R(>sourcc»s, Divi Stewart, D.P.C. and Cameron, K.C. (1992) Effect of sion of Parks, Sacramento, California. trampling on the soils of the St. James Walkway, Merriam, L.C. and Smith, C.K. (1 974) Visitor impact New Zealand. Soil Use and Management 8, on newly developed campsites in the Boundary 30-36. Waters Canoe Area. l(Hirnal of Eoredtr\ 72, Sun, D. and Liddle, M.J. (1993a) A survey of tram 627-830. plingeffects on vegetation and soil ineight trop Monti, P. and Mackintosh, E.t. (1979) Effect of camp ical and subtropical sites. Environmental ing on surface soil pro|:)erties in the bcrreal Management 17, 497-510. fc:)rest region ot northwestern Ontario, Canada. Sun, D. ancJ Liddle, M.J. (1993b) Plant morphological Soil Science Society of America Journal 43, characteristics and resistance to simulated tram 1024-1029. pling. Environmental Management17, 511-521. Mcjnz, C.A. (2002) The response of two arctic tundra Tachibana, H. (1969) Vegetation changes of a moor plant communities to human trampling distur in Mt. Hakkoda caused by human treading. bance. Journal ot Environmental Management Ecological Review 17, 177-188. 64, 207-217. Taylor, J.Y. (1997) Leave only footprints? How back- Moritsch, B.J. and Muir, P.S. (199?) Subalpine reveg- country campsite use affects forest structure. etation in Yosemite National Park, California: Yellowstone Science 5, 14-17. changes in vegetation alter three vears. Natural Wagar, J.A. (1961) How to predict which vegetated Areas journal 1 ?, I 5 5- H) ?. areas will stand up best under 'active' recrea Newsome, I)., Moore, S.A. and Dowling, R.K. (2002) tion. American Recreation journal 1, 20-21. Natural Area Touri.'^m: Ecolop\. Impacts and Wagar,|.A. (1964)Thecarryingcapacity ofwild lands Management. ( hanncd Vi(>w Publications, for recreation. Forest Science Monograph 7. Clevedon, UK. Society of American Foresters, Washington, DC. Obua, J. and I larding, D.M. (1997) Environmental Whinam, j. and Chilcott, N. (1999) Impacts of tram im|ia(t of ecotoLirism in Kibale Nation

alpine environments of the Central Plateau, Wilderness Ecosystems, Threats and Manage Tasmania. Journal of Environmental Manage ment. Proceedings RMKS-P-1 3-VC)L-5. US ment 40. 103-117. Department of Agriculture, Forest Service, Wilson, J.P. and Seney,).P. (1994) Erosional impact of Rocky Mountain Research Station, Ogden, hikers, horses, motorcycles, and off-road bicy Utah, pp. 172-178. cles on mountain trails in Montana. Mountain Zabinski, C.A. and Cannon, j.F. (1 907) F.llec ts ot rec Research and Development 14, 77-88. reational impacts on soil microbial communities. Yoda, A. and Watanabe, T. (2000) Erosion of moun Environmental Management 21,2 13-238. tain hiking trail over a seven-year period in Zabinski, C.A., DeLuca, T.F1., Cole, D.N. and Daisetsuzan National Park, central Hokkaido, Moynahan, O.S. (2002) Restoration ot highly Japan, in; Cole, D.N., McCool, S.F., Borrie, W.T. impacted campsites in the EagleCap Wilderness, and O'Loughlin, j. (comps) Wilderness Science Oregon. Restoration Ecology 10, 27.S-281. in a Time of Change Conference. Vol. 5.