Intense road development and urbanization have fragmented the natural landscapeacross coastal Southern California since the middle of the 20th century. As mitigation
efforts, in 1992 the Natural Community Conservation Plan and Habitat Conservation Plans I
and II (NCCP&HCP I and II) allocated reserves and non-reserve open spaces to connect
these fragmented natural habitats and foster the coexistence of wildlife and people in
Orange County. Here, I aim to evaluate the effectiveness of two established wildlife
corridors (the Sand Canyon Wash Corridor and the Bonita Creek Corridor) in southern
Orange County, linking two large reserve areas (Figure 1). I conducted camera trapping
surveys by using 11 cameras placed along these two linkage corridors. Additionally, I
obtained more photographic data at 10 different camera stations within the Irvine Ranch
Water District (IRWD) San Joaquin Marsh & Wildlife Sanctuary. Then, I calculated Relative
Abundance Index (RAI) values based on the photographic capture rates of key vertebrate
species of concern for each location. I compared the current RAI values with values from a
study by Lyren et al. (2008) to illustrate the changes over a decade at three subsets of
locations. I also obtained wildlife-vehicle collision (WVC) data from 2005 to 2019 from the
City of Irvine Local Animal Services. I found an average of two bobcat mortalities event per
year occurred until 2015. After 2015, no bobcat detection or roadkill mortality is observed.
Additionally, the number of coyote detections has increased by almost 700% over a decade
at these locations. It is likely that this result reflects urban coyotes’ greater ability to
function in a changing environment and (greater) resilience to anthropogenic effects. The
long-term success of wildlife corridors requires understanding how the regional environment may influence species composition and potential use of these linkage elements reserve designs over extended periods.