Impacts of human recreation on carnivores in protected areas
April
Impacts of human recreation on carnivores in protected areas
Angela Darnell Baker¤ 0 1 2
Paul L. Leberg 0 1 2
0 Current address: Humboldt State University, Wildlife Department , Arcata, California , United States of America
1 Department of Biology, University of Louisiana at Lafayette , Lafayette, Louisiana , United States of America
2 Editor: AndreÂs Viña, Michigan State University , UNITED STATES
Mammalian carnivores can be particularly sensitive to human disturbance, even within protected areas (PAs). Our objective was to understand how human disturbance affects carnivore communities in southern Arizona, USA by studying habitat occupancy based on data collected using non-invasive methods in three PAs with different levels of human disturbance. Carnivore occupancy varied based on human disturbance variables (i.e., roads, trails, etc.). Common carnivore species (coyotes, gray foxes, and bobcats) had high occupancy probability in highly disturbed sites, while all other carnivore species had a higher probability of occupancy in low disturbance protected areas. Additionally, overall carnivore diversity was higher in PAs with low human disturbance. Edges of PAs appeared to negatively impact occupancy of nearly all carnivore species. We also found the presence of roads and trails, and not necessarily how much they are used, had a significant negative impact on the occupancy of most carnivore species. Furthermore, the overall level of disturbance within a PA influenced how sensitive carnivores were to human disturbance variables. Carnivores were more sensitive in PAs with higher levels of disturbance and were relatively unaffected by disturbance variables in a PA with low base levels of disturbance. Increased visitation to PAs, expected with the region's high level of population growth, is likely to cause shifts in the carnivore communities favoring species that are less sensitive to disturbance.
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Funding: Funding was provided by the Graduate
Student Organization at the University of Louisiana
at Lafayette and from generous donors facilitated
through Instrumentl Crowdfunding. The funders
had no role in study design, data collection and
analysis, decision to publish, or preparation of the
manuscript.
Competing interests: The authors have declared
that no competing interests exist.
Introduction
Mammalian carnivores are often a vital component of ecosystems, influencing community
structure, stability, and diversity [1±4]. They can also be important surrogate species for
conservation priorities, acting as indicators of biodiversity, umbrella species, or flagship species in
their respective ecosystems [5±7]. Human disturbance has been shown to affect the diversity,
composition, and structure of many communities [8±10], and carnivores are particularly
sensitive to human disturbance due to their relatively large body sizes, large home ranges, low
fecundity, long generation times, and low populations densities [2, 11, 12]. Adding to their
vulnerability is the fact that they often come into conflict with humans [13]. Cardillo, Purvis [14]
found that intrinsic biological factors, such as those mentioned above, interact with human
population density to account for a large portion of the extinction risk of carnivores. Thus, in
many parts of the world, protected areas (PAs) are the last available refuge for carnivore
species and are essential to their persistence [11, 14, 15].
Margules and Pressey [16] contend that one of the primary roles of a PA is to separate the
diversity of organisms within it from the activities that threaten their existence. We considered
a PA as an area dedicated to and managed for the ª. . .conservation of nature with associated
ecosystem services and cultural valuesº [
17
]. Examples of such areas in the United States
would include state and national parks and forests, conservation easements, and wildlife
refuges. Although carnivores in these PAs may not face hunting mortality, they are not immune
to the impacts of human disturbance [18, 19]. Most PAs allow access for hiking, camping, and
other recreational activities, all of which can have significant impacts on wildlife [20±22]. Reed
and Merenlender [23] found that quiet, non-consumptive recreational activities (e.g., hiking)
resulted in a significant decrease in density (5x fewer) of native carnivores compared to PAs
that were not open to the public. A recent review found that 59% of studies documented
negative effects of recreation in protected areas on wildlife [24]. As the impacts on carnivore
communities may have far reaching impacts on ecosystems, determining the effects of human
disturbance in PAs is therefore essential for improving science-based conservation policies
[
15, 25, 26
].
The carnivore community of the southwestern United States has been relatively
understudied. Although there are published studies that focus on individual or small subsets of species
(e.g., [
27
],[
28
]), examinations of the broader (...truncated)