A framework for modeling habitat quality in disturbance‐prone areas demonstrated with woodland caribou and wildfire

Abstract

Abstract. Natural resource management professionals require adaptable spatial tools for conserving and managing wildlife across landscapes. These tools should integrate multiple components of habitat quality and incorporate local disturbance regimes. We provide a spatial modeling framework that integrates three components of habitat (nutritional resources, connectivity, and predation risk) into indices of habitat quality under a simulated wildfire disturbance regime. Woodland caribou (Rangifer tarandus caribou), a species of conservation concern, is used to illustrate our framework. We simulated disturbance from wildfire on two boreal forest landscapes to produce stand ages, from which we computed and integrated the three habitat indicator components using different schemes. Spatial variation in the influence of wildfire and the distribution of the three components of habitat resulted in heterogeneous patterns of habitat quality. The inclusion of disturbance led to a different habitat quality landscape than that of a static model in which the influence of wildfire on vegetation communities was not considered, incorporating the likelihood of persistence into the overall representation of habitat quality. The integration of nutrition, connectivity, and predation risk into a single index of habitat quality produced spatial patterns distinct from maps of the individual components. Regardless of whether the components were combined through additive, multiplicative, or minimum habitat quality threshold methods, areas of very high-and poor-quality habitat were found at consistent locations across the landscape, suggesting that these two types of regions provide opportunities for long-term management interventions. The framework presented here is adaptable and modular; it could be modified and applied to other species, regions, and disturbance regimes. It provides a nuanced representation of persistent habitat and has the potential to be a useful tool for conservation planning.

Tactical departures and strategic arrivals: Divergent effects of climate and weather on caribou spring migrations

“…, Whitman et al. ). Furthermore, warmer winters may lead to more frequent thaw‐freeze or rain‐on‐snow icing events which can make vegetation under the snow inaccessible (Gunn , Albon et al.…”

“…Thus, research has mainly focused on direct and indirect effects of climate on forage availability. For example, caribou winter forage comprises primarily slow-growing terrestrial lichens (Joly et al 2007(Joly et al , 2010 which are negatively impacted by the warming-induced increases in drought, wildfire regimes, and tree pathogens occurring throughout boreal regions (Joly et al 2009, de Groot et al 2013, Whitman et al 2017. Furthermore, warmer winters may lead to more frequent thaw-freeze or rain-onsnow icing events which can make vegetation under the snow inaccessible (Gunn 2003, causing mass mortalities in exceptional cases (Miller andBarry 2009, Forbes et al 2016).…”

Potential impacts of climate change on the habitat of boreal woodland caribou

“…We included nutritional resources and risk of predation and disease (hereafter "habitat-quality modules") as the two components of habitat-quality most important for caribou. Reclassification weights for each season were derived from published studies that reported resource selection functions (Boyce et al 2002), supplemented by expertbased inference where necessary (Muhly et al 2015, Whitman et al 2017). Reclassification weights for each season were derived from published studies that reported resource selection functions (Boyce et al 2002), supplemented by expertbased inference where necessary (Muhly et al 2015, Whitman et al 2017).…”

“…Predation and disease.-We reclassified vegetation cover and patch age into two raster layers that accounted for the risk of predation by black bears, Whitman et al (2017). and the risk of predation and disease associated with white-tailed deer.…”

“…Habitat-quality.-We modeled overall habitatquality by the additive combination of the nutrition and predation risk modules (see Whitman et al 2017 for details on habitat-quality component combination schemes), and by scaling the result from 0 to 1. In comparison with a multiplicative approach, an additive combination makes no assumptions about the ecology of the species.…”