Generic-to-Nuanced Gradient of Response to Anthropogenic Change
Taken altogether, these results support the idea that bobcats and
coyotes are at different ends of the generic-to-nuanced response
gradient. Bobcats exhibited a “broad-stroke”, generic response to
human modification. When faced with human modification, bobcats expanded
their home ranges and functionally responded in their selection in a
predictable manner with little temporal variation and complexity in
their resource selection overall. These results corroborate previous
work that shows that bobcats avoid humans (e.g., Reilly et al. 2022) and
rely on corridors across a development gradient (Popescu et al. 2021,
Mayer et al. 2022). In contrast, human modification did not affect
coyote home range size, but it did cause coyotes to have more
temporally-acute resource selection behaviors and varied and complex
functional responses in their resource selection, which often changed
temporally in intensity or direction. Compared to bobcats, coyotes were
able to fine-tune their spatial behavior by avoiding the aspects of
human modification that were disadvantageous on a finer scale within
their home range instead of expanding their range. While it might be
unanticipated that a species adapted to coexistence with humans would
avoid human modification, this avoidance of human-associated areas
(Gosselink et al. 2003) is a part of their adjustment strategy. Coyote
temporal adjustments have been documented, including changing habitat
preferences on a daily scale to avoid risk (Petroelje et al. 2021,
Rivera et al. 2021) and on a seasonal scale to exploit seasonal
resources (Webster et al. 2022). The overall nuance of coyote response
to human modification illustrates how a species’ response to novel
environments can occur on multiple scales. These responses highlight
differences in population-level plasticity between the two species.
Focusing on multiple aspects of space-use by investigating home-ranging
behaviors and resource selection including spatial, temporal, and
individual variation allowed us to reveal the complexity and differences
in mesocarnivores’ responses to anthropogenic disturbance. While
investigating functional responses in resource selection is becoming
more common (Godvik et al. 2009, Herfindal et al. 2009), investigating
temporal variation in these functional responses is rarely done, yet
considering this aspect is critical in understanding the degree of
nuance in spatial behavior. However, using these characteristics allowed
us to develop the generic-to-nuanced gradient, a framework where we can
categorize species based on several spatial behaviors and highlight how
a species is responding to anthropogenic change. Finding where a species
or population falls along the generic-to-nuanced gradient described here
can have important conservation and management implications. As human
modification continues, understanding the full extent of its effects on
wildlife population dynamics and fitness (Webber et al. 2020) as a
result of individual- and population-level responses is increasingly
crucial. Species that are less plastic are more likely to be
disadvantaged in high-disturbance environments, while behavioral
flexibility leads to increased success and tolerance of anthropogenic
environments (Lowry et al. 2013, Lovell et al. 2022). For example,
bobcat populations in North America only recently began recovering after
record lows in the 1900’s (Roberts and Crimmins 2010), while coyote
populations have both increased in number and range across North America
with anthropogenic land changes and extirpation of large predators
(Linnell and Strand 2000, Laliberte and Ripple 2004), illustrating the
implications of species-level plasticity and tolerance to human
modification. However, while a nuanced response to human modification
can provide benefits in exploiting anthropogenic habitat, there are also
risks associated with this behavior. Forty-two percent of the coyotes in
this study (n =13) were killed (hunted or trapped) within one year
after being collared. While coyote abundance in this population appeared
to remain stable despite these mortalities, it remains that there is a
risk to individuals coexisting with humans.
The gradient of nuance in spatial response described here could be used
as another metric to predict how species will react to future changes,
and potentially as how best to manage them. Rettie and Messier (2000)
proposed the “hierarchy of limiting factors” hypothesis, stating that
species will display space-use response at a broader scale to address
their most limiting factors. Similar to this idea, species on the
generic end of the spectrum appear to respond to human development by
displaying broad spatial response, indicating that habitat itself might
be their biggest limiting factor (Rettie and Messier 2000). As such,
managing species like bobcats should focus on habitat manipulation to
mitigate blanket responses in home range size and habitat selection.
Species on the nuanced end of the spectrum, like coyotes, may respond
more to factors impacting the type of interactions with humans, such as
harvest management, because they can be more flexible in habitat use and
risk avoidance on a temporal scale. In such, our generic-to-nuanced
framework highlights the importance of investigating spatial, temporal
and individual responses to elucidate how other species might be
impacted by human activities and how to best mitigate these activities.