Predator Spatial Behavior and Response to Human Modification
While sex had no effect on bobcat home range size, study site did have a
significant effect. Overall, increased levels of human modification
within home range was correlated with larger home range size in bobcats.
Bobcats tend to use larger home ranges in more fragmented and developed
landscapes (Riley et al. 2003, Tucker et al. 2008) and lynx (Lynx
lynx ) have been found to expand their home ranges in order to increase
hunting efforts in areas with declining prey abundance (Schmidt 2008).
Therefore, the fragmentated, patchy landscape and increased human
modification in the central Illinois site could be leading to
low-quality forage for bobcats, causing them to expand their home ranges
to maintain access to necessary resources (Reding et al. 2013, Nielsen
et al. 2017). Coyotes had larger home ranges than bobcats, but a large
amount of variation was present within the coyote population (Gese et
al. 1988, Grinder and Krausman 2001). Sex and study site accounted for
some of that observed variation, but neither had a significant effect on
home range size. Other coyote populations have increased home range size
with more forest cover (Ellington and Murray 2015), but coyote home
ranges in this study were unaffected by the large difference in forest
cover between the two study sites. In addition, there was no correlation
between human modification within their home ranges and home range size
in coyotes. This lack of response is likely due to coyotes adapting to
human modification in their home ranges in other ways, such as spatial
choices within their home ranges (Gehrt et al. 2009) or temporal
adaptations to human activity (Gaynor et al. 2018, Shamoon et al. 2018).
Coyotes displayed a higher degree of temporal adjustment in their
resource selection coefficients than bobcats; their responses were more
varied depending on the temporal period, both diel and by season, than
bobcats. We observed bobcat tolerance of human modification and exurban
habitat regardless of temporal period, which was unexpected based on
previous studies (e.g., Reed et al. 2017). Bobcats could be diluting the
human density within their home ranges by expanding their home ranges in
response to human modification, becoming less negatively affected by
human modification and exurban areas overall. This dilution is possible
as long as human use is below a certain intensity (Nielsen and Woolf
2001, OrdeƱana et al. 2010).
Bobcats and coyotes both adjusted their responses to agriculture,
exurban habitat, and water depending on the degree of human modification
around them. Bobcat functional responses to human modification in their
home ranges were straightforward, selecting more agriculture, less
exurban habitat, and areas closer to water as human modification
increased. This means that human modification does impact bobcat
behavior, causing them to adjust their use of habitat accordingly, which
was expected (Flores-Morales et al. 2019). The directionality of these
trends was consistent when they were present regardless of the temporal
period, although the strength of the trend sometimes varied by temporal
period. Coyotes had a more varied response to human modification, and
cumulative (mean) annual responses did not always reflect trends in
individual temporal periods. In addition, regressions were sometimes
quadratic and changed direction after a threshold of human modification.
Overall, coyote functional responses to human modification were more
nuanced and temporally-acute than those of bobcats.