TITLE:
Canid Social Structure and Density Dependence Improve Predator-Prey Models of Canis latrans and Lepus californicus in Curlew Valley, UT
AUTHORS:
Shannon Kay, Jim Powell, Frederick Knowlton
KEYWORDS:
Coyotes, Jackrabbits, Oscillations, Predator-Prey Cycles, Model Competition
JOURNAL NAME:
Open Journal of Ecology,
Vol.5 No.4,
April
2,
2015
ABSTRACT: Prominent examples of predator-prey oscillations
between prey-specific predators exist, but long-term data sets showing these oscillations are uncommon. We explored
various models to describe the oscillating behavior of coyote (Canis
latrans) and black-tailed jackrabbits (Lepus californicus) abundances
in a sagebrush-steppe community in Curlew Valley, UT over a 31-year period
between 1962 and 1993. We tested both continuous and discrete models which
accounted for a variety of mechanisms to discriminate the most important
factors affecting the time series. Both species displayed cycles in abundance
with three distinct peaks at ten-year intervals. The coupled oscillations
appear greater in the mid-seventies and a permanent increase in the coyote
density seems apparent. Several factors could have influenced this
predator-prey system including seasonality, predator satiation, density
dependence, social structure among coyotes, and a change in the coyote bounty
that took place during the course of data collection. Maximum likelihood estimation
was used to obtain parameter values for the models, and Akaike Information
Criterion (AIC) values were used to compare models. Coyote social structure and
limiting resources in the form of density-dependence and satiation seemed to be
important factors affecting population dynamics.