Simulating the effects of climate change on fire regimes in Arctic biomes: implications for caribou and moose habitat

Abstract

Citation: Joly, K., P. A. Duffy, and T. S. Rupp. 2012. Simulating the effects of climate change on fire regimes in Arctic biomes: implications for caribou and moose habitat. Ecosphere 3(5):36. http://dx.doi.org/10.1890/ES12-00012.1Abstract. Wildfire is the primary ecological driver of succession in the boreal forest and may become increasingly important within tundra ecosystems as the Arctic warms. Migratory barren-ground caribou (Rangifer tarandus granti ) rely heavily on terricolous lichens to sustain them through the winter months. Lichens preferred by caribou can take 50 or more years to recover after being consumed by wildfires. We simulated effects of climate change on the fire regime within the winter range of one of the largest caribou herds in the world, the Western Arctic Herd, to assess how their forage may be impacted. We forecast that the total area burned (AB) in the near term (2008-2053) will be 0-30% greater than during our historic reference period depending on the climate model (CGCM3.1 or ECHAM5) considered. Further into the future (i.e., 2054-2099), we forecast AB to increase 25-53% more than during our reference period. In contrast to the entire study area, which contains both tundra and boreal forest habitats, we forecast that the amount of AB in tundra alone will increase (0-61%) in the near term. Simulated highquality caribou winter range, as indexed by tundra and spruce habitat that had not burned in 50 years, decreased modestly (,6%) in the near term over the entire study area. Simulated changes were more dramatic within the herd's core winter range, with declines in high-quality caribou winter range approaching 30%. Conversely, moose habitat was projected to increase by 19-64% within the core winter range in the near term. The simulated declines in the quantity of core winter range in the future due to larger and more frequent fires could impact caribou abundance through decreased nutritional performance and/or apparent competition with moose. These impacts would likely be detrimental to the subsistence users that rely on this resource. Additionally, changes in the fire regime and decreases in caribou abundance could amplify feedback mechanisms, such as decreasing albedo, by facilitating shrub growth that may hasten climate-driven changes to the composition and structure of vegetation communities in the low Arctic.

Evaluating Potential Effects of an Industrial Road on Winter Habitat of Caribou in North-Central Alaska

“…This likely will not be the case, especially given that lichens destroyed by fire will recover over time (Joly et al, 2010;Collins et al, 2011) and vegetation is projected to undergo changes associated with climate change (Euskirchen et al, 2009). Fire is anticipated to increase in the region (Joly et al, 2012), which could further reduce winter habitat quality in the study area, as we observed in its eastern portion. Indeed, the level of industrial development that caribou can tolerate before it affects the population has been shown to be a function of the percentage of habitat disturbed by fire in the past 50 years (Sorensen et al, 2008).…”

Observed and predicted effects of climate change on Arctic caribou and reindeer

“…The northern expansion of ungulate species, such as moose (Alces alces) (Norment et al 1999) and white-tailed deer (Odocoileus virginianus) (Veitch 2001;Dawe and Boutin 2016) could increase interspecific competition for certain forage species and introduce novel pathogens to Rangifer populations (Kutz et al 2009). For example, increases in productivity on the tundra and more frequent wildfire activity (which increases the proportion of immature to mature forests) on migratory caribou winter ranges (see section below) is predicted to improve habitat quality for moose and resultantly increase their abundance on caribou ranges (Sharma et al 2009;Joly et al 2012).…”

“…Climate change is predicted to affect Rangifer populations both positively and negatively through a variety of mechanisms, including increased wildfire activity on winter ranges, increased summer insect harassment, changing forage quality and quantity in the summer and winter, increased icing events in winter, changing spring phenology, and changes to distributions and mi-gratory behaviour (Sharma et al 2009;Joly et al 2012;Witter et al 2012a;Loe et al 2016;Albon et al 2017;Le Corre et al 2017). The extensive distribution of Rangifer globally ( Fig.…”

Distribution of barren‐ground caribou during winter in response to fire

“…Large losses in the amount of forested habitats occurred between 1990 and 2000 (GNWT 2010); approximately 30-35% of treed wintering areas burned (Chen et al 2013). Assuming that current climatic trends continue (IPCC 2007), an increase in fire activity across northern landscapes will further reduce the availability of forested taiga for caribou (Joly et al 2012, Gustine et al 2014). In addition, warmer annual temperatures may have consequences for lichen abundance via changes in the composition of plant communities (Cornelissen et al 2001, Olthof et al 2008.…”

“…An increase in the frequency and severity of fire is predicted to impact northern landscapes (Rupp et al 2006), potentially reducing the quantity and altering the distribution of lichen resources available to caribou during winter (Cornelissen et al 2001, Olthof et al 2008, Joly et al 2012. Furthermore, a warming climate may influence the broad-scale distribution and composition of plant communities in the Arctic (Cornelissen et al 2001, Høye et al 2007, Olthof et al 2008, Lang et al 2012, as well as snow conditions and the frequency of extreme winterweather events (Tews et al 2007, Vors andBoyce 2009).…”