Article

Does Repeated Human Intrusion Alter Use of Wildland Sites by Red Squirrels? Multiyear Experimental Evidence

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Abstract

Intrusion by humans into wildlife habitat during recreational activities has become a worldwide conservation concern. Low levels of intrusion, which occur frequently in many wildlands, could influence use of sites by red squirrels (Tamiasciurus hudsonicus) and have important ramifications for conservation. Red squirrels can influence forest composition and regeneration by feeding on conifer buds, seeds, and vascular tissues, and they prey on avian nests. Attraction of red squirrels could increase the risk of these activities, whereas displacement of red squirrels may exacerbate demographic problems for small populations of red squirrels in isolated habitats. We implemented experimental intrusions during 10 consecutive weeks of the red squirrel breeding season, 1 or 2 times/week (1990-1993) in 1 area and 5 times/week (1991-1993) in another area in Wyoming. Each intrusion lasted 1 h and involved 1 person. Abundance of red squirrels at intruded sites did not differ significantly from that at control sites during either experiment. However, experiments should be conducted to examine longer-term effects and effects of higher levels of intrusion because alteration of distributions of red squirrels may affect forest conditions and demographics or fitness of birds and red squirrels.

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... Red squirrels, like other tree squirrels, are diurnal (Gurnell, 1987;Steele, 1998) and leave evidence of their presence, such as nests, feeding sites, vocalizations, and middens (Finley, 1969;Gurnell, 1984). Surveys for evidence, especially middens, are the best method to detect red squirrels (Finley, 1969;Vahle and Patton, 1983;Price, 1994;Mattson and Reinhart, 1996;Gutzwiller and Riffell, 2008), as the animal itself may not be observed during surveys or be represented in trapping efforts. Our team was part of the University of Arizona Red Squirrel Monitoring Program with collectively .12 ...
... They also make bolus nests made of leaves, grasses, and lichens (Steele, 1998;Young et al., 2002) that are visible in the canopy of trees. Surveys such as ours are the best method for detecting red squirrels (Finley, 1969;Vahle and Patton, 1983;Price, 1994;Mattson and Reinhart, 1996;Gutzwiller and Riffell, 2008). Our survey was the most extensive attempt to determine the status of red squirrels within the Guadalupe Mountains of Texas. ...
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... While research in the field of "recreation ecology" has typically focused on the direct impacts of human activities on species and ecological systems in protected areas (Monz et al., 2013), there is an increasing recognition of the role that recreation-and associated food subsidies-play in aggregating and promoting unnaturally high densities of human-associated wildlife species at relatively small, but heavily-visited sites in protected areas (Hopkins et al., 2014;Walker and Marzluff, 2015). Elevated densities of these synanthropic species can promote biotic interactions that result in indirect, negative effects on the rarer, more sensitive species protected areas are intended to conserve (Bradley et al., 2003;Gutzwiller and Riffell, 2008;Marzluff and Neatherlin, 2006;Robb et al., 2008). However, little is known about the extent to which local food subsidies in protected areas may benefit overabundant synanthropic species (and impact sensitive species) at broader spatial scales via source-sink dynamics. ...
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While protected areas are a cornerstone of biodiversity conservation, human activities in these areas can negatively affect native species in direct and indirect ways. However, the potential effects of food subsidies provided by visitors on the local- and landscape-scale population dynamics of overabundant species, and how these effects may be augmented by human development outside of parks, are largely unexplored. Here, we investigated how human foods at heavily-visited sites within California parks benefited populations of Steller's jays (Cyanocitta stelleri), an overabundant predator of a threatened seabird that nests in remnant old-growth forests. Our study population was heavily subsidized with both juveniles and adults consuming substantial amounts of human foods by biomass (46% and 57%, respectively), as indicated by stable isotope analyses. Juvenile survival, adult survival, and fecundity—estimated from radio-telemetry data—were high and the population was projected to grow rapidly (25% annually). Most juveniles dispersed from parks following seasonal declines in human visitation to areas with high housing densities and more stable resources—with almost half of dispersers returning to old-growth forests the following breeding season. Thus, we found that local food subsidies at heavily-visited sites promoted source populations of jays that may bolster populations in old-growth forests at broader spatial scales, and that this effect was likely augmented by more temporally stable resources in developed areas outside of parks during the nonbreeding season. These novel results indicate that curbing populations of overabundant predators may require reductions in food subsidies both within protected areas and surrounding landscapes.
... In Wyoming, the abundance of red squirrels subjected to low levels of disturbance (1-5 human disturbance events per week) did not differ from controls, although higher disturbance levels may have revealed effects. [504] However, small mammals endemic to California chaparral habitat were less diverse and abundant in disturbed sites, with the opposite patterns for disturbance-associated species; this related to changes in vegetation associated with trails and roads rather than directly linked to specific disturbance or level of use, the latter which were not studied. [126] In Colorado, prairie dogs were more wary of humans with dogs than humans alone, although they showed antipredator responses in both situations. ...
Technical Report
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Metro is the regional government in the Portland, Oregon area. Thanks to the region’s voters, the agency has acquired approximately 17,000 acres of natural areas to protect water quality, wildlife habitat and connect people with nature. The goal of this document is to better understand the trade-offs between different types and levels of recreational access in the context of our work to protect habitat and water quality, and provide access to nature in a growing urban area. Only by thoroughly understanding the effects of recreational activities on wildlife and water quality are we able to avoid, minimize and mitigate potential harm to the resources we are committed to protecting. Recreation ecology is the scientific study of environmental impacts resulting from recreational activity in protected natural areas. The nature of a literature review is to summarize what has been studied, what has been learned, and what the experts have concluded. This document reviews the literature on overall and relative effects of three user groups – hikers, mountain bikers and equestrians – on trails, habitat, and wildlife to help inform ecologically appropriate placement and construction of trails in natural areas. Studies are reviewed from the U.S. and elsewhere, with a focus on soft-surface trails in natural areas. We included limited information about other non-motorized trail user groups such as trail runners and beach walkers. Motorized off-road vehicles were omitted from this review because they are generally not allowed on natural area trails within the urban and near-urban region. A previous literature review on the effects of dogs on wildlife and water quality is included as Appendix 1. Studies vary in terminology for our recreational groups of interest. In this report “hiker” generally means a person walking along a trail for various reasons such as exercise, wildlife watching or moving between places. “Mountain biker” refers to a non-motorized bicycle rider on a soft or natural surface trail; alternative terms in the literature include off-road bicyclists or off-road cyclists. “Equestrian” refers to a person riding a horse on a trail. Throughout the text we refer to these as “user groups.” Trails provide people with important opportunities to improve health and well-being, and providing access to nature is especially important in urban areas.[2-5] However, as indicated in various literature reviews, trails and trail use can damage natural areas including negatively affecting soils, vegetation, water quality, plants, and animals.[6-27] Damage to trails or habitats and negative effects on wildlife are more likely when trails are inappropriately located, designed, constructed, maintained or used, or when unauthorized trails are allowed to proliferate. These issues can also increase trail maintenance costs[28-30] and negatively affect visitors’ experience.[31-33] This document reviews the types of recreational effects in Chapters 2-7, including information about user group-specific effects. Each chapter includes a summary of key points. Chapter 8 offers information on how to minimize, monitor and manage effects. Throughout the review we provide representative study examples with additional citations. We paid close attention to the effects of recreation on wildlife (Chapters 6 and 7) because they are less well documented than physical effects such as erosion or vegetation damage. Scientific names for species mentioned in the text are in Appendix 2. For wildlife, human disturbance increases animals’ stress and can cause them to hide, change behavior or flee. Some species, such as those that do well in urban areas, are generalists and can tolerate human disturbance. Other species such as pregnant animals, long-distance migrants, and habitat specialists tend to be more stressed and displaced by trail users. Some species may permanently leave a natural area. Figure 1 illustrates the relationships between environmental, trail design, recreational use and their effects on trail damage, water quality, vegetation damage and wildlife...
... Slight levels of intrusion introduced by human presence for short periods of time do not decrease abundance of red squirrels (Gutzwiller and Riffell, 2008). However, we demonstrated that red squirrel occurrence decreased as traffic noise increased, although we could not completely exclude other traffic disturbance that may not have a linear relationship with distance to roads such as visual disturbance and chemical pollution. ...
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Habitat fragmentation, destruction, and disturbance are major threats to biodiversity. Global road networks represent one of the most significant human impacts on ecosystems, and a spatially extensive source of anthropogenic disturbance and noise. We developed a novel approach by combining traffic monitoring with noise mapping on the basis of a standardized traffic-noise stimulus generated by controlled vehicle operation to investigate temporal and spatial heterogeneity of traffic noise. We used animal presence or absence, radio-telemetric monitoring of space use, and remotely sensed habitat characteristics with occupancy modeling and spatial analysis to assess influences of distance from roads, habitat characteristics, and traffic noise level on site occupancy and space use of Mt. Graham red squirrels (Tamiasciurus hudsonicus grahamensis). Traffic noise had spatially extensive and negative effects on site occupancy. Animal occurrence decreased as traffic noise increased after accounting for distance from roads. Traffic noise levels in animal core home ranges were lower than noise levels within total home ranges. Our study disentangled effects of traffic noise from confounding environmental characteristics and demonstrated the chronic impacts of traffic noise on animal distribution. We highlight the importance of incorporating spatial and temporal heterogeneity of traffic noise at a local scale when investigating effects of anthropogenic noise on wildlife.
... La reducción en el uso de esta estación coincidió con el aumento en el uso de máquinas ruidosas como motobombas y motosierras en el lote vecino. Así, nuestros resultados parecen concordar con los encontrados en un bosque natural en Estados Unidos, donde se demostró que las ardillas de cola roja responden con cambios en el uso del espacio por la intrusión humana, disminuyendo su forrajeo y alejándose de los territorios perturbados (Gutzwiller y Riffell 2008). ...
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... However, other studies on birds (e.g. Baines and Richardson 2007;Picozzi 1971;Newton et al. 1981;Gutzwiller et al. 1998), deer (Langbein and Putman 1992;Recarte et al. 1998) and red squirrels (Gutzwiller and Riffell 2008), suggest that, generally, walking as a recreational activity does not have significant long term impacts on animal behaviour. Studies on mountain biking indicate that this form of recreation can disturb wildlife (Cessford 1995; Taylor and Knight 2003;George and Crooks 2006;Naylor et al. 2009). ...
Article
Forests are popular locations for outdoor recreation and there is considerable evidence highlighting the positive social impacts of these activities. There is also a body of research outlining the range of potentially negative impacts of recreation on wildlife and habitats. This paper provides a summary of current social and natural scientific knowledge on disturbance caused by walking, cycling, mountain biking, horse riding, off-road vehicles use, camping, and some other recreational activities in forests. We identify more than 40 ecological studies of recreational impacts on forests. Greatest attention has been directed towards walking as an activity and the impacts upon birds, soils and flora although long-term ecological studies of wildlife or habitat disturbance are scarce. Impacts include trampling by foot, hoof and tyre, animal behaviour change and the spread of pests and pathogens. Considerably less work has been carried out on the social dimensions of recreational disturbance. In this article the authors draw on behaviour theory in an attempt to identify the key factors influencing human behaviour in the context of recreational disturbance. Cognitive theories highlight the importance of attitudes and behavioural control, whilst social practice theories emphasise the impact of behavioural routines and contexts. Management actions may be better targeted at promoting alternative behaviours rather than trying to prevent current ‘problem’ behaviours. We advocate greater engagement with these theories to better integrate social science with ecological studies, and improve understanding and management of interactions between recreation needs and conservation.
Thesis
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Chapter
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It is well known that statistical power calculations can be valuable in planning an experiment. There is also a large lit- erature advocating that power calculations be made when- ever one performs a statistical test of a hypothesis and one obtains a statistically nonsignicant result. Advocates of such post-experiment power calculations claim the calcu- lations should be used to aid in the interpretation of the experimental results. This approach, which appears in vari- ous forms, is fundamentally flawed. We document that the problem is extensive and present arguments to demonstrate the flaw in the logic.
Article
Through attraction of avian nest predators, human activity near nests is known to cause lower nesting success or nest failure in some species. This is a significant conservation issue because man), wildlands are subjected to repeated intrusion by recreationists, ecotourists, and other user groups during avian breeding seasons. Yet, wildlife scientists still have limited knowledge about the extent to which repeated human intrusion attracts avian nest predators. We studied this topic in subalpine forest in Wyoming, USA, and experimented with the gray jay (Perisoreus canadensis), a nest predator that is known to approach recreationists. During 1989-1993, we implemented intrusions within 20 circular 1-ha (113-m-diam) sites for I or 2 hr each week during a 10-week period when potential passerine prey were breeding. Simultaneously, 10 circular 1-ha control sites did not receive experimental intrusions. The average number of gray jays on intruded sites was higher than that on control sites by 156% (1989), 225% (1990), 59% (1991), 13% (1992), and 29% (1993). The probability of gray jay recurrence on intruded sites was higher than that on control sites by 125% (1989), 300% (1990), 20% (1991), 33% (1992), and 20% (1993). By increasing the number and recurrence of gray jays, relatively low levels of repeated intrusion can increase the potential for nest predation by grayjays. We caution that additional work is necessary to assess whether attraction of gray jays actually leads to increased nest predation. Knowledge of when intrusion does and does not attract gray jays is important because information about both events is necessary to define the levels and circumstances of intrusion that are influential. Wildlife managers can use knowledge about intrusion-induced attraction of avian nest predators to help decide whether or how recreational activity in wildlands should be managed.
Article
Low levels of human intrusion have become ubiquitous, yet the distance at which they affect bird distributions remains unclear. By testing for changes in bird abundance, we assessed uht ther low lo cls of intrusion altered bird distributions within and beyond intruded sites. In Wyoming subalpine forests, we experimentally implemented intrusions within circular 1.0-ha (113-m diameter) sites for 1-2 hr (Snowy Mountains, 1989-1993) or for 5 hr (Pole Mountain, 1991-1993) each week during 10 consecutive weeks of the breeding season. The intrusions did not displace birds during most years, with the following exceptions. Mean abundances for Mountain Chickadee (Parus gambeli) in the Snowy Mountains (1992) and at pole Mountain (1993), and mean abundances for American Robin (Turdus migratorius) and Hermit Thrush (Catharus guttatus) in the Snowy Mountains (1989), were 46-57% low er within intruded sites than they were within control sites. Intrusion did not influence abundances outside of the 1.0-ha intruded sites. Minimum detectable effect sizes (R(2)s for the intrusion effect) were 18-32%: effects of this magnitude and larger were detectable with a probability of 0.80. We would therefore have readily detected moderate and large abundance changes had they occurred. The spatial extent of intrusion effects on distributions was thus limited to the actual sires of intrusion, and the effects occurred infrequently. Knowledge about the distance at which low levels of intrusion do and do not alter bird distributions is essential for protecting intrusion-sensitive species and avoiding unnecessary restrictions on landscape use by the public.
Article
The seasonal timing of male song during breeding affects the timing of territory establishment, mate attraction, pair formation, egg laying, and transmission of information about breeding songs to young. Thus, alteration of the seasonal timing of song may influence reproductive success and survivorship. Human intrusion has the potential to influence avian singing behavior. Accordingly, we determined whether repeated intrusion affected the seasonal timing of male song for three passerines (Ruby-crowned Kinglet [Regulus calendula], Yellow-rumped Warbler [Dendroica coronata], Dark-eyed Junco [Junco hyemalis]) in Wyoming forests. Intrusions involved one person walking through habitats for 1-2 h (Snowy Mountains, 1989-1993) or for 5 h (Pole Mountain, 1991-1993) each week for 10 consecutive weeks of each breeding season. For most comparisons, we did not detect a significant difference in the seasonal timing of singing activity between control and intruded sites. Two exceptions were: (1) the mean singing date for Ruby-crowned Kinglets was 11 days earlier on intruded sites than on control sites at Pole Mountain; and (2) the proportion of intruded sites with singing by Yellow-rumped Warblers (0.40) was smaller than that for control sites (1.00) during mid-June at Pole Mountain. Moderate and large differences in the timing of singing activity were detectable with a probability of 0.80, but small differences were not reliably detectable. Thus, our results are a conservative estimate of the effects of intrusion on the seasonal timing of song. Curtailment of singing on intruded sites may have reduced breeding activity and, consequently, the quality of those sites for producing young. Because intrusion-induced effects often are context-specific and can vary among individuals and species, and because our results are conservative, avian ecologists should continue to assess whether intrusion influences seasonal patterns of singing activity.
Article
In 1989, 1990, and 1991, we conducted experiments on 30 circular 1.0-ha sites to assess whether human intrusions during a 10-week period influenced the occurrence and consistency of primary song in breeding subalpine birds. Using only those weekly censuses during which a species was present at a site, we computed song occurrence as the percentage of censuses during which a species sang, and we calculated singing consistency as the maximum number of consecutive censuses during which a species sang. An intrusion bout involved one person who walked through a site for 1 or 2 h. We used a priori contrasts, involving habitat covariates when appropriate, to assess differences in song occurrence and singing consistency between control and intruded sites and between sites at which the inner 25% of the site was disturbed (S25) and those at which 100% of the site was disturbed (S100). Singing by a number of species did not appear to be influenced by intrusion. For several species, however, song occurrence and singing consistency were higher on control sites than on intruded sites, indicating intrusion reduced singing activity. Song occurrence was higher on S100 relative to S25 sites as well. This latter pattern may have emerged because all of the individuals using the S100 sites were able to observe us during repeated intrusions and discern that we were not predators, whereas most of the individuals using the S25 sites likely did not have this opportunity. Thus, some of the individuals using S25 sites may have reduced their singing to avoid detection by us. Because song is essential in territory defense, mate acquisition, and in other reproductive activities, levels of intrusion that alter normal singing behavior have the potential to lower the reproductive fitness of males that are sensitive to this form of disturbance.
Article
We examined whether forest fragmentation by agriculture influenced the abundance of North American red squirrels (Tamiasciurus hudsonicus) in the southern boreal mixedwood forest of Saskatchewan. During the summers of 1995 and 1997, we determined the relative abundance of red squirrels in 43 forest fragments ranging in size from 0.2 to 82 ha and in 15 sites in nearby contiguous forest. Relative abundance was determined using acoustic point count surveys, in which all squirrel vocalizations were recorded. Within the fragmented agricultural landscape, we found that red squirrel abundance increased slightly with forest-fragment size, whereas the abundance of red squirrels was negatively correlated with the amount of forest cover within 1 km of a site. We also compared squirrel abundance in forest fragments with that in contiguous forest and found that red squirrels were significantly more abundant in forest fragments than in contiguous forest. We speculate that changes in dispersal patterns in fragmented forest habitats, higher squirrel survival in forest fragments, and differences in diet between contiguous and fragmented forest habitats contributed to this pattern. Our results suggest that forest fragmentation may not be particularly detrimental to habitat generalists like the red squirrel. However, an increased abundance of red squirrels in forest fragments may result in negative effects on other species, such as forest songbirds.
Article
Reconciling tree harvesting with the maintenance of forest bird populations is a major concern of integrated management. Because bird nest predation causes >50% of the nest losses in passerines and is known to vary according to habitat characteristics, we explored some aspects of avian nest predation in relation to forestry practices in a boreal coniferous landscape managed primarily for timber production in Quebec. Using artificial tree and ground nests with Common Quail (Coturnix coturnix) and plasticine eggs, we compared the risk of nest predation (1) in experimental riparian forest strips of different widths (20-m, 40-m, and 60-m unthinned strips; >300-m control strips; and 20-m thinned strips) and (2) in clearcuts experimentally subjected to different regeneration practices (plantations with chemical and mechanical weeding, and naturally regenerated clearcuts) between 1992 and 1995. The risk of ground nest predation was lower in naturally regenerated clearcuts (5% daily probability of predation) than in control forest strips (27%). We found no evidence that chemical and mechanical weeding affected the risk of nest predation in clearcuts. In forest strips, the predation risk was higher in forest strips 40-60 m wide than in 20-m and control strips. Birds accounted for 13% of predation signs, whereas red squirrels (Tamiasciurus hudsonicus) were the dominant mammalian predators, accounting for 36% of the total predation (n = 201 nests preyed upon). In our region, the low predation rates (30% for 24 real nests) and the absence of generalist foragers such as crows, raccoons, and skunks could be attributed to the near absence of human occupation in comparison to forest-dominated landscapes in Europe and northeastern United States.
Article
Empirical evidence to assess the hypothesis that nest predation pressure influences avian assemblage composition is mostly lacking. We examined distribution of predation risk for artificial bird nests in the understory of coniferous and deciduous forests in southeastern Alaska and adjacent western Canada to determine whether habitat-specific nest predation pressure could be a factor influencing habitat selection and, in turn, breeding bird diversity. Two sizes of open-cup nests were constructed of natural materials and placed in nest sites representative of those used by local breeding bird species although, on average, artificial nests were more conspicuous than natural nests monitored in a companion study. Artificial nests were exposed to predation during early and late nesting seasons in 1993 and 1994. Principal nest predators identified using automated cameras were red squirrel (Tamiasciurus hudsonicus), Steller's Jay (Cyanocitta stelleri; Alaska only), Gray Jay (Perisoreus canadensis; Canada only), and small mammals. Systematic point-count censuses recorded significantly more red squirrels than jays in coniferous forest, and both jay species reached peak abundances at the border between coniferous and deciduous forest, relative to interior forest of both types. In repeated-measures analysis of variance, predation of artificial nests was significantly higher in coniferous than deciduous forest, and greater for large (thrush size) than for small (warbler size) nests. Nest height (shrub vs. ground) was not an important factor, due to a significant interaction with time (early vs. late nesting season). Natural and artificial nest predation losses were comparable in deciduous forest, but artificial nests were more susceptible than natural nests in coniferous forest understory. Artificial nest losses reflected the distribution of predators, especially red squirrels, and was negatively associated with breeding bird diversity in northwestern forest understory - confirming that nest predation pressure is one (of several) plausible determinants of avian habitat selection and assemblage organization.
Article
We reviewed 64 published investigations concerning effects of human disturbance on nesting colonial waterbirds. We summarized and reviewed articles, based on taxonomy, examining investigator, ecotourist, recreator, watercraft, and aircraft activity. effects on physiology, reproductive behavior, reproductive success, and population trends of waterbirds. Though most studies found significant negative effects, taking careful measures minimized impact on some species. Guidelines for minimizing investigator and visitor disturbance are outlined. Little practical information for visitor management is available. Increasing pressure from the ecotourism industry to visit waterbird colonies makes research that develops scientifically-defensible tourism policies imperative
Article
Movement and settlement patterns of animal offspring, along with the costs of occupying familiar and unfamiliar habitats, have been inferred frequently, but rarely have they been documented directly. To obtain such information, we monitored the individual fates of 205 (94%) of the 219 offspring born over 3 yr in a population of the North American red squirrel (Tamiasciurus hudsonicus), at Fort Assiniboine, Alberta, Canada (54.20 degrees N, 114.45 degrees W). We located neonates by radio-tracking mother squirrels, and thereafter we documented the movements, survival, and settlement patterns of the offspring, using a combination of telemetry, live-trapping, and visual observations. Prior to settlement, offspring made forays of up to 900 m ((X) over bar = 126 m) off the natal territory, but they did not abandon the natal territory until they had settled on their own territory. Foray distance was not related to the age or size of the offspring. We used the locations of offspring kills to show that the risk of predation significantly increased when the offspring were travelling off of their natal territories. Just under half of the 73 offspring that acquired territories did so on or immediately adjacent to their mother's; the farthest settlement distance was only 323 m from the natal territory, or about the distance of three territory widths. Movement data from adults in the population showed that all offspring settled within potential contact of their mother (and possibly their father). Offspring that settled relatively farther away from their natal territory were more likely to obtain larger territories, with traditional hoarding and overwintering sites (middens). These offspring also had higher overwinter survival, suggesting that the costs of making forays off the natal territory may be balanced by the advantages of locating a superior territory.
Article
Ecotourism helps to protect many habitats, but may also have negative impacts on wildlife. We investigated effects of ecotourists on reproductive success of hoatzins (Opisthocomus hoazin) and on hormonal status of their chicks in Amazonian rainforest lakes by comparing birds from undisturbed and from tourist-exposed nests. Hatching success was similar in both groups but chick survival was much lower at tourist-exposed nests than at undisturbed nests. This effect was due to an increased mortality of juveniles prior to fledging whereas small nestlings seemed largely unaffected. Juveniles, but not nestlings, living at tourist-exposed sites had a lower body mass and showed a stronger hormonal response to experimental stress compared to individuals at undisturbed sites. These data suggest that juvenile hoatzins were susceptible to tourist-induced stress which in turn may be responsible for the lower survival. In contrast, adult hoatzins that were incubating had apparently habituated to tourist presence because their flush distances at tourist-exposed nests were 50% lower than at undisturbed sites. Our findings demonstrate that individuals in different life stages show different susceptibilities to tourism. We suggest that even just watching animals during breeding can threaten their survival, but a proper scientific management of off-limit zones and area-specific guidelines for wildlife observation could reduce harmful effects.
Article
Increasing urbanization and recreational activities around and within biodiversity hotspots require an understanding of how to reduce the impacts of human disturbance on more than a single species; however, we lack a general framework to study multiple species. One approach is to expand on knowledge about the theory of anti‐predator behaviour to understand and predict how different species might respond to humans. We reviewed the literature and found that only 21% of studies that used a behavioural approach to study human disturbance focused on multiple species. These studies identified a number of potential predictive variables. We developed a simulation model that investigates interspecific variation in different parameters of disturbance with variation in human visitation. We found that fitness‐related responses, such as the quantity of food consumed by a species, are relatively sensitive to the distance at which animals detect humans, the frequency of disturbance by humans and the interaction of these factors, but are less sensitive to other characteristics. We examined avian alert distance (the distance animals first orientated to an approaching threat, a proxy for detection distance) across 150 species, controlling for phylogenetic effects. We found that larger species had greater alert distances than smaller species, which could increase local spatial and temporal limitations on suitable habitat with increasing human visitation. Synthesis and applications . Our results suggest that body size could be a potential predictor of responses to human disturbance across species, and could be used by managers to make conservation decisions regarding levels of human visitation to a protected site. We suggest that three things are essential to develop predictive models of how different species will respond to human disturbance. First, multiple indicators of disturbance should be studied to select those with lower intraspecific variation for a given study system. Secondly, the species‐specific nature of responses should be identified. Thirdly, life history, natural history and other correlates with these species‐specific responses must be assessed.
Article
Cooperation between the United States Department of Agriculture (USDA) Forest Service and the United States Department of Interior (USDI) National Park Service is most often advocated to protect biological diversity on national forests and parks, but the agencies, so far, have done little to implement the biodiversity mandates of such laws as the Endangered Species Act and the National Forest Management Act. The ideological and political history of the Forest Service and Park Service is explored to determine the roots of interagency conflicts. Several recent models of cooperative reform are also critiqued and found to be insufficient to stimulate better working relationships. To protect biodiversity, cooperation must be framed within conservation biology and must place primary emphasis on ecosystem patterns and processes as well as on individual species. Increased education of agency managers, ecosystem-level research, local and regional public participation, scientific oversight committees, new legislation, and enlightened leadership also play important roles. Ultimately, management policies must be reframed within a context of ecocentric values.
Article
The effect of human disturbance on animals is frequently measured in terms of changes in behaviour in response to human presence. The magnitude of these changes in behaviour is then often used as a measure of the relative susceptibility of species to disturbance; for example species which show strong avoidance of human presence are often considered to be in greater need of protection from disturbance than those which do not. In this paper we discuss whether such changes in behaviour are likely to be good measures of the relative susceptibility of species, and suggest that their use may result in confusion when determining conservation priorities.
Article
Fragmentation of breeding habitat may cause declines in many bird populations. Our perception of the demographic effects of habitat fragmentation comes primarily from studies in the midwestern and eastern United States and Scandinavia. We know very little about the demographic effects of anthropogenically caused habitat fragmentation in habitats prone to natural disturbance, as is typical of most forest types in the western United States. We located and monitored 1916 nests on eight sites located in mostly forested landscapes and eight sites located in primarily agricultural landscapes to study the effects of landscape-level fragmentation on nest predation and brood parasitism in riparian areas in western Montana. Patterns of nest predation were opposite those documented from more eastern locales; predation rates were higher in forested landscapes than in fragmented landscapes dominated by agriculture. This pattern probably reflects the importance of forest predators in these landscapes. Red squirrels (Tamiasciurus hudsonicus) were much more abundant in forested landscapes and declined quickly with decreasing forest cover, whereas predators that typically increase in fragmented landscapes in the Midwest (such as corvids) increased only at very high levels of fragmentation. Patch size and distance to habitat edge did not influence predation rates. Brood parasitism by Brown-headed Cowbirds (Molothrus ater) decreased with increasing forest cover, but the strongest predictors of parasitism were the abundance of human development (farms and houses) on the landscape and the density of cowbird host species, not forest cover. The combined effects of predation and parasitism resulted in low nestmg productivity in both forested and agricultural landscapes for heavily parasitized species, while the species not affected by cowbird parasitism had greater nesting productivity in fragmented agricultural landscapes. Our results suggest that the effects of fragmentation are dependent on the habitat structure, the landscape context, the predator community, and the impact of parasitism. All of these factors may differ substantially in western ecosystems when compared to previously studied forests, making generalizations about the effect of fragmentation difficult.
Assessment and management of wildland recreational disturbance
  • K. J. Gutzwiller
  • D. N. Cole
  • C. E. Braun
GUTZWILLER, K. J., AND D. N. COLE. 2005. Assessment and management of wildland recreational disturbance. Pp. 779-796 in Techniques for wildlife investigations and management (C. E. Braun, ed.). 6th ed. The Wildlife Society, Bethesda, Maryland.
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STEELE, M. A. 1998. Tamiasciurus hudsonicus. Mammalian Species 586:1-9.
YOUMANS (COORDS.). 1999. Effects of recreation on Rocky Mountain wildlife: a review for Montana
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JOSLIN, G., AND H. YOUMANS (COORDS.). 1999. Effects of recreation on Rocky Mountain wildlife: a review for Montana. Montana Chapter of The Wildlife Society, Helena.
Origin of wildlife responses to recreationists. Pp. 81–91 in Wildlife and recreationists: coexis-tence through management and research Movements, survival, and settlement of red squirrel (Tamiasciurus hudsonicus) offspring
  • R L Knight
  • S A And
  • D C Temple
  • K W Larsen
  • S And
  • Boutin
KNIGHT, R. L., AND S. A. TEMPLE. 1995. Origin of wildlife responses to recreationists. Pp. 81–91 in Wildlife and recreationists: coexis-tence through management and research (R. L. Knight and K. J. Gutzwiller, eds.). Island Press, Washington, D.C. LARSEN, K. W., AND S. BOUTIN. 1994. Movements, survival, and settlement of red squirrel (Tamiasciurus hudsonicus) offspring. Ecology 75:214–223.
Stan played a pivotal role in securing funding, arranging for research vehicles, and supplying other logistical support. It was a great pleasure to work with him. We are grateful to the technicians who collected and compiled field data, including
  • H Stanley
  • R Anderson
  • J Aley
  • S Bates
  • K Beauchaine
  • W Clements
  • T Gladbach
  • E King
  • H Kroese
  • G Marcum
  • V Pauley
  • J Plsek
  • J Roberts
  • C Roth
  • K Runyon
  • R Trzcinski
We dedicate this paper to the late Dr. Stanley H. Anderson. Stan played a pivotal role in securing funding, arranging for research vehicles, and supplying other logistical support. It was a great pleasure to work with him. We are grateful to the technicians who collected and compiled field data, including R. Aley, J. Bates, S. Beauchaine, K. Clements, W. Gladbach, T. King, E. Kroese, H. Marcum, G. Pauley, V. Plsek, J. Roberts, J. Roth, C. Runyon, K. Trzcinski, R.
Origin of wildlife responses to recreationists. Pp. 81–91 in Wildlife and recreationists: coexistence through management and research
  • And S A Temple
KNIGHT, R. L., AND S. A. TEMPLE. 1995. Origin of wildlife responses to recreationists. Pp. 81–91 in Wildlife and recreationists: coexistence through management and research (R. L. Knight and K. J. Gutzwiller, eds.). Island Press, Washington, D.C.
Exposure to ecotourism reduces survival and affects stress response in hoatzin chicks (Opisthocomus hoazin)
  • A Mü Llner
  • K E Linsenmair
  • M Wikelski
MÜ LLNER, A., K. E. LINSENMAIR, AND M. WIKELSKI. 2004. Exposure to ecotourism reduces survival and affects stress response in hoatzin chicks (Opisthocomus hoazin). Biological Conservation 118:549-558.