Estimating occupancy and predicting numbers of gray wolf packs in Montana using hunter surveys

Abstract

Reliable knowledge of the status and trend of carnivore populations is critical to their conservation and management. Methods for monitoring carnivores, however, are challenging to conduct across large spatial scales. In the Northern Rocky Mountains, wildlife managers need a time‐ and cost‐efficient method for monitoring gray wolf (Canis lupus) populations. Montana Fish, Wildlife and Parks (MFWP) conducts annual telephone surveys of >50,000 deer and elk hunters. We explored how survey data on hunters' sightings of wolves could be used to estimate the occupancy and distribution of wolf packs and predict their abundance in Montana for 2007–2009. We assessed model utility by comparing our predictions to MFWP minimum known number of wolf packs. We minimized false positive detections by identifying a patch as occupied if 2–25 wolves were detected by ≥3 hunters. Overall, estimates of the occupancy and distribution of wolf packs were generally consistent with known distributions. Our predictions of the total area occupied increased from 2007 to 2009 and predicted numbers of wolf packs were approximately 1.34–1.46 times the MFWP minimum counts for each year of the survey. Our results indicate that multi‐season occupancy models based on public sightings can be used to monitor populations and changes in the spatial distribution of territorial carnivores across large areas where alternative methods may be limited by personnel, time, accessibility, and budget constraints. © 2013 The Wildlife Society.

Stable pack abundance and distribution in a harvested wolf population

“…We surveyed registered ungulate hunters for observations of live wolves made during the hunting season through an online hunter reporting form used by AEP at the end of each hunting season (Rich et al , Ausband et al , Ausband and Bassing ). Ungulate hunting seasons occurred from 1 September–20 January each year (Alberta Government ) and hunters reported observations made within each week of the hunting season (Ausband and Bassing ).…”

“…We excluded hunter observations when only single wolves were reported, only wolf sign (i.e., tracks or howling) was reported, inadequate location data were reported, or an observation was made outside the hunting season (Rich et al , Ausband et al ). We truncated hunter survey data to include only observations of wolves made September–December to minimize violating the assumption of population closure (MacKenzie et al ).…”

“…We used observation data from both survey methods to generate detection histories of wolf packs in southwestern Alberta following methods described by Rich et al () and Ausband et al (). We arbitrarily superimposed a grid of 1,000‐km 2 cells across the study area; each cell represented a sample unit.…”

“…Alternatively, we hypothesized that the abundance and distribution of wolf packs were generally stable regardless of harvest and predicted infrequent changes in occupancy associated with harvest of wolves in southwestern Alberta. We then evaluated the relative importance of harvest compared to environmental factors that have already been reported to explain pack occupancy in the Rocky Mountains (e.g., forest cover and cattle density; Rich et al , Ausband et al ) to determine the dominant factors associated with pack abundance and distribution in a harvested population of wolves.…”

Camera traps as a tool for Carnivore conservation in a mosaic of Protected Areas in the Pantanal wetlands, Brazil

“…Camera trapping has proved to be one of the most useful tools for wildlife surveys as it is non-invasive and provides information on cryptic and inconspicuous species (Harmsen et al, 2009;Sarmento et al, 2009;Surnato et al, 2013). Data obtained from camera trapping can be used to study several topics of animal ecology such as inventories (Srbek-Araujo & Chiarello, 2005;Tobler et al, 2008), site occupancy (Mackenzie & Royle, 2005;O'Connell et al, 2006;Rich et al, 2013), patterns of spatial partitioning among species (Sarmento et al, 2011;Sollmann et al, 2012), temporal interactions between species as well as activity patterns (Foster et al, 2013;Frey et al, 2017). In the last two decades, several factors contributing to Neotropical carnivore coexistence have been studied using camera trapping (Vieira & Port, 2007;Di Bitetti et al, 2010;Bianchi et al, 2016).…”