Search

White-tailed jackrabbits (Lepus townsendii) were once abundant in North America and provided a number of ecosystem services such as seed dispersal, nutrient cycling, facilitating the persistence of other species, and serving as a prey species for predators, including golden eagles (Aquila chrysaetos), bobcats (Lynx rufus), and numerous others. Reports describe declines and extirpations across much of their range, but given the extremely limited research available, it is difficult to determine what factors have led to reductions of white-tailed jackrabbits. Researchers have investigated few areas of white-tailed jackrabbit ecology, including the possible effects of climate change, habitat degradation and loss, competition with black-tailed jackrabbits (Lepus californicus), and changes in predator composition. We review the life history and research available on white-tailed jackrabbits, discuss possible causes of their decline, suggest areas that require additional research, and make recommendations regarding their management.

Relationships between different measures of stability are not well understood in part because empiricists and theoreticians tend to measure different aspects and most studies only explore a single form of stability. Using time-series data from experimental plankton communities, we compared temporal stability typically measured by empiricists (coefficient of variation in biomass) to stability measures typically measured by theoreticians derived from the community matrix (asymptotic resilience, initial resilience and intrinsic stochastic invariability) using first-order multivariate autoregressive models (MAR). Community matrices were also used to derive estimates of interaction strengths between plankton groups. We found no relationship between temporal stability and stability measures derived from the community matrix. Weaker interaction strengths were generally associated with higher stability for community matrix measures of stability, but were not consistently associated with higher temporal stability. Temporal stability and stability measures derived from the community matrix stability appear to represent different aspects of stability reflecting the multi-dimensionality of stability.

During the last century, the distribution of the woodchuck (Marmota monax) has expanded westward in parts of the Great Plains. Expansive grasslands of the Great Plains were formerly a barrier to forest-dwelling species, but changes since European settlement have enabled some woodland species to colonize the region. By 2000, woodchucks generally reached across the central portion of Nebraska. We compiled new county records and estimated the continued westward expansion rate of this large, diurnal squirrel in Nebraska. We documented new records of M. monax along much of the former western distributional limits in central and southern parts of the state, including a large westward movement along the Platte River into central Keith County. Westward movements appear to follow wooded rivers and their tributaries throughout the state. We estimated that in the last 18 years, M. monax expanded westward along the Platte River from central to western Nebraska at a rate of 9–13 km/year. If not already present in northeastern Colorado, M. monax could reach the Colorado border in