Assessment Of Prey Vulnerability Through Analysis Of Wolf Movements And Kill Sites

Abstract

Within predator-prey systems behavior can heavily influence spatial dynamics, and accordingly, the theoretical study of how spatial dynamics relate to stability within these systems has a rich history. However, our understanding of these behaviors in large mammalian systems is poorly developed. To address the relationship between predator selection patterns, prey density, and prey vulnerability, we quantified selection patterns for two fine-scale behaviors of a recovering wolf (Canis lupus) population in Yellowstone National Park, Wyoming, USA. Wolf spatial data were collected between November and May from 1998-1999 until 2001-2002. Over four winters, 244 aerial locations, 522 ground-based telemetry locations, 1287 km of movement data from snow tracking, and the locations of 279 wolf kill sites were recorded. There was evidence that elk (Cervus elaphus) and bison (Bison bison) densities had a weak effect on the sites where wolves traveled and made kills. Wolf movements showed a strong selection for geothermal areas, meadows, and areas near various types of habitat edges. Proximity to edge and habitat class also had a strong influence on the locations where elk were most vulnerable to predation. There was little evidence that wolf kill sites differed from the places where wolves traveled, indicating that elk vulnerability influenced where wolves selected to travel. Our results indicate that elk are more vulnerable to wolves under certain conditions and that wolves are capable of selecting for these conditions. As such, vulnerability plays a central role in predator-prey behavioral games and can potentially impact the systems to which they relate.

Long‐ and short‐term temporal variability in habitat selection of a top predator

“…For example, cougars (Puma concolor), which also tend to hunt at night, exhibit diurnal patterns of habitat selection that differ from the noctural ones (Dickson et al 2005). Second, wolves may not be selecting habitat, within their territories, on the basis of elk density, but on the basis of areas where elk are easier to encounter and kill (Bergman et al 2006, Milakovic et al 2011. Similarly, Serengeti lions select habitats with good cover that increase their chances to kill their prey more than habitats where prey is more abundant (Hopcraft et al 2005).…”

“…Wolves did select habitat on the basis of forest cover, elevation, and slope. These are certainly important features to wolf predation (Mao et al 2005, Bergman et al 2006, Kauffman et al 2007, Gervasi et al 2013 and it is plausible that wolves' preferences with respect to hunting grounds are captured by those features. We suggest that, with respect to the predator-prey relationship, predator habitat selection at small spatial scale, like the one used in our study, is driven by features of the landscape that enhance hunting success, rather than overall prey distribution.…”

“…First, for those three years we had information on the spatial distribution of elk (Cervus elaphus), which are the primary prey for these wolves (Smith et al 2004). The sites where wolves kill prey seem to be influenced, not so much by the presence of elk, but instead by the presense of habitats that increase the probability of a successful kill (Bergman et al 2006, Kauffman et al 2007). Nevertheless, the extent to which wolves' habitat preferences correspond with overall elk distribution remains unclear.…”

Evaluating the landscape of fear between apex predatory sharks and mobile sea turtles across a large dynamic seascape

“…Central to the model is that prey must forage and survive in both their home range and that of their predators; thus, an animal's knowledge of safe and risky areas within its home range is paramount for survival (Laundre´et al 2010). By contrast, predators that can adapt their behavior to 12 E-mail: nhammerschlag@rsmas.miami.edu target vulnerable prey within their home ranges will have increased feeding success and fitness advantages (Bergman et al 2006). The basic landscape of fear model predicts that as an animal's landscape changes from low to high risk of predation, it will alter its behavior to risk avoidance.…”

Comparisons and Trends in White-tailed Deer, <em>Odocoileus virginianus</em>, Body Fat in Northeastern Minnesota, 1974-1990

“…Schaller 1972;Scheel 1993;Moore 2002;Khan et al 2004). Vulnerability of an individual is typically defined by the age and health of the individual (Bergman et al 2006). Determining differential selection is difficult because predation events are rarely witnessed and then it is even more complicated for biologists to determine the ultimate versus proximate cause of death.…”