Enhanced shrub growth in the Arctic increases habitat connectivity for browsing herbivores

Abstract

Habitat connectivity is a key factor influencing species range dynamics. Rapid warming in the Arctic is leading to widespread heterogeneous shrub expansion, but impacts of these habitat changes on range dynamics for large herbivores are not well understood. We use the climate–shrub–moose system of northern Alaska as a case study to examine how shrub habitat will respond to predicted future warming, and how these changes may impact habitat connectivity and the distribution of moose (Alces alces). We used a 19 year moose location dataset, a 568 km transect of field shrub sampling, and forecasted warming scenarios with regional downscaling to map current and projected shrub habitat for moose on the North Slope of Alaska. The tall‐shrub habitat for moose exhibited a dendritic spatial configuration correlated with river corridor networks and mean July temperature. Warming scenarios predict that moose habitat will more than double by 2099. Forecasted warming is predicted to increase the spatial cohesion of the habitat network that diminishes effects of fragmentation, which improves overall habitat quality and likely expands the range of moose. These findings demonstrate how climate change may increase habitat connectivity and alter the distributions of shrub herbivores in the Arctic, including creation of novel communities and ecosystems.

Aufeis as a Major Forcing Mechanism for Channel Avulsion and Implications of Warming Climate

“…(2021) found that aufeis facilitates the existence of rich and spatially extensive groundwater‐dependent invertebrate communities with significantly different community structure than those present in surface habitats. River corridors in this tundra environment attract migratory songbirds (Winner, 2003), shorebirds (Johnson et al., 2007), waterfowl (Larned et al., 2012), and willow ptarmigan ( Lagopus lagopus ) (Christie et al., 2014), as well as moose ( Alces alces ) (Zhou et al., 2020) and other wildlife. The distribution of individual fish species varies among rivers, but Dolly Varden ( Salvelinus malma ), Arctic cisco ( Coregonus autumnalis ) (M. P. Carey et al., 2021), broad whitefish (Leppi et al., 2022), chum salmon ( Oncorhynchus keta ) (Craig & Haldorson, 1986), Arctic grayling ( Thymallus arcticus ) (West et al., 1992), and other fish species (P. C. Craig, 1989) use the active channels in most coastal plain rivers.…”

Wolverines (Gulo gulo) in the Arctic: Revisiting distribution and identifying research and conservation priorities amid rapid environmental change

“…Arctic shrubification is driving a northward range expansion of moose, beaver, and snowshoe hare, all species identified by modern studies to be consumed by wolverines in Arctic Alaska despite their arrival to the region only decades ago (Tape et al 2016a , b , 2018 ). The availability of these species to wolverines will likely continue to increase under climate change (Zhou et al 2020 ). Conversely, wintertime ground-icing events, which are increasingly common and severe with climate change, are dampening the peaks of Arvicoline population cycles and driving mass mortality events in caribou and muskoxen (Aars and Ims 2002 ; Kohler and Aanes 2004 ; Ims et al 2008 ; Jenkins et al 2011 ).…”

Characterizing Wetland Inundation and Vegetation Dynamics in the Arctic Coastal Plain Using Recent Satellite Data and Field Photos

“…These studies found evidence of shrub expansion (alder, willow, dwarf birch, etc.) in northern Alaska [5,48], with changes most often found on hill slopes and in valley bottoms [49]. However, shrub expansion was not uniform, and some areas exhibited no increase at all [47].…”