An eighteen-year spatial and temporal analysis of the recolonization of a disjunct population of gray wolves (Canis lupus)

Abstract

Most gray wolves in the United States live in disjunct populations. Management of isolated populations is important in sustaining the species. The Central Forest Region (CFR) of Wisconsin is home to one such disjunct population. Wolves began recolonizing the CFR in the early to mid-1990s. In this study, wolf recolonization was divided into three distinct Time Periods: Early (1994-1999), Mid (2000-2005), and Late (2006-2012). Habitat Classes of individual pack territories were defined as Optimal, Mixed, and Marginal, based on features known to influence wolf habitat selection or avoidance. These were: (1) percent public land, (2) percent agriculture, and (3) road density. The influence of Time Period and Habitat Class on pack territory size, mid-winter pack size, reproductive performance, wolf-human conflicts, human-caused wolf mortalities, territory persistence and reproductive persistence were analyzed. Pack demographics were similar across Time Periods, except that pup production was slightly lower during the Mid Time Period than during Late. Marginal Habitat packs had smaller mid-winter pack sizes, fewer pups in mid-summer, increased conflicts with humans, five times greater human-caused mortalities, and lower reproductive persistence. Pack territory location matters. Results show how increasingly human-altered landscapes affect wolves’ viability and indicates the extent to which wolf recolonization may or may not be successful