Monitoring and Habitat Analysis for Wolves in Upper Michigan

Abstract

Gray wolves (Canis lupus) in upper Michigan, USA, have been monitored since 1991 when breeding activity in mainland Michigan was documented for the first time since 1954. Based on winter track counts, the mean annual rate of increase in abundance was 19% from 1995 to 2002, with the population reaching an estimated 278 animals in 2002. Our objectives were to (1) increase the efficiency of wolf management in Michigan by evaluating alternative and less extensive sampling approaches for population estimation, and (2) evaluate habitat for wolves based on occupancy after a decade of recovery. For the first analysis, we created 22 discrete sampling units that cover upper Michigan, and we evaluated abundance estimates based on various sampling plans using known distribution and populations from the 2000-2002 winter track surveys. We evaluated each plan based on the precision, bias, and confidence interval coverage. A random sampling plan with regression estimator returned the most precise estimates, but a stratified sampling plan, using low, medium, and high wolf density strata had the greatest precision at lowest effort. For the habitat evaluation, we compared white-tailed (Odocoileus virginianus) deer density and road density between wolf pack locations from 1995 to 2001 to random locations outside of the current wolf range. We estimated white-tailed deer density by a spatial interpolation of pellet group counts. Our resource selection function indicated that probability of wolf occupation of an area was positively correlated with deer density, and it was relatively constant for road densities <0.4 km/km 2 but declined sharply at higher road densities. For areas habitable by wolves in upper Michigan, we predict a road density threshold of 0.7 km/km 2 and a deer density threshold of approximately 2.3-5.8 deer/km 2 . We believe that these results will aid managers who need to estimate wolf abundance and predict wolf distribution. JOURNAL OF WILDLIFE MANAGEMENT 69(4):1660-1669; 2005

Wolf habitat selection is shaped by human activities in a highly managed boreal forest

“…Nevertheless, retaining the complete model support our main hypothesis and means that all the anthropogenic disturbances and their cumulative effects that we a priori considered as being important to understand wolf behaviour truly influence habitat selection patterns. Previous studies showed that wolf distribution at the landscape scale is influenced primarily by prey availability and human infrastructure (Mladenoff et al, 1995;Potvin et al, 2005b), but we demonstrate that wolf habitat selection pattern at a fine scale is influenced by complex interactions between habitat attributes and human disturbances (see also Ciucci et al, 2003;Houle et al, 2010). Wolves are habitat generalists that adapt their habitat selection behaviour to prey species availability (Mech and Boitani, 2003).…”

Defining the predator landscape of northeastern British Columbia.

“…Human disturbance in the region is currently limited to hunting and trapping, and a lightly used 63 ATV trail that crosses the southern portion of the study area through the territory of the Nevis pack. Most wolf studies have been concerned with occupancy, i.e., predicting where wolves will occur by identifying suitable habitat on the landscape for future colonization based on where wolves currently reside (e.g., Mladenoff et al 1995Mladenoff et al , 1999Mladenoff and Sickley 1998;Carroll et al 2003;Gehring and Potter 2005;Potvin et al 2005;Oakleaf et al 2006). In contrast, I examined the activities and dynamics of a resident wolf population that is currently free of human disturbance.…”

“…These factors should be reflected in patterns of fine-scale habitat selection that can be used in managing for resource development. Processes within home ranges have largely been ignored in ecological studies of wolves, partly because of their designation as habitat generalists and partly because of general conclusions from broad-scale studies that relate wolf occupancy of a landscape to prey density (Fuller 1989;Messier 1995;Potvin et al 2005) and road density (Mladenoff et al 1995). As a result, wolf management has largely taken the view that as long as prey densities are sufficient to support wolf populations and as long as road densities (as an index of human-caused mortality) remain below a threshold of 0.58 km/km 2 (Thiel 1985;Fuller 1989;sic Carroll et al 2000), wolves will persist.…”

Ecological thresholds in herb communities for the management of suburban fragmented forests

“…We performed GAMs using Poisson error, as Poisson error is best suited to model species richness (Quinn and Keough, 2002); analyses using normal error and log-transformed species richness yielded identical results. We subsequently identified the presence and position of threshold(s) by visual inspection of the plots of fitted values (Potvin et al, 2005;Ficetola and Denoë l, in press). To improve the reliability of the estimate, the position of threshold was assessed by five independent people and averaged.…”