Arctic biodiversity: increasing richness accompanies shrinking refugia for a cold‐associated tundra fauna

Abstract

Abstract. As ancestral biodiversity responded dynamically to late-Quaternary climate changes, so are extant organisms responding to the warming trajectory of the Anthropocene. Ecological predictive modeling, statistical hypothesis tests, and genetic signatures of demographic change can provide a powerful integrated toolset for investigating these biodiversity responses to climate change, and relative resiliency across different communities. Within the biotic province of Beringia, we analyzed specimen localities and DNA sequences from 28 mammal species associated with boreal forest and Arctic tundra biomes to assess both historical distributional and evolutionary responses and then forecasted future changes based on statistical assessments of past and present trajectories, and quantified distributional and demographic changes in relation to major management regions within the study area. We addressed three sets of hypotheses associated with aspects of methodological, biological, and socio-political importance by asking (1) what is the consistency among implications of predicted changes based on the results of both ecological and evolutionary analyses; (2) what are the ecological and evolutionary implications of climate change considering either total regional diversity or distinct communities associated with major biomes; and (3) are there differences in management implications across regions? Our results indicate increasing Arctic richness through time that highlights a potential state shift across the Arctic landscape. However, within distinct ecological communities, we found a predicted decline in the range and effective population size of tundra species into several discrete refugial areas. Consistency in results based on a combination of both ecological and evolutionary approaches demonstrates increased statistical confidence by applying cross-discipline comparative analyses to conservation of biodiversity, particularly considering variable management regimes that seek to balance sustainable ecosystems with other anthropogenic values. Refugial areas for cold-adapted taxa appear to be persistent across both warm and cold climate phases and although fragmented, constitute vital regions for persistence of Arctic mammals.

A trait‐based framework for discerning drivers of species co‐occurrence across heterogeneous landscapes

“…Even if detailed environmental reconstructions are not available, basic knowledge of site conditions can be used with our approach to address the drivers of community structure through time. The rapid and global environmental changes we are currently experiencing are leading to shifts in species ranges and community composition, which are likely to have profound ecological implications (Williams and Jackson 2007, Alexander et al 2015, Hope et al 2015, Terry and Rowe 2015. Understanding the impact of these changes and predicting their future effects on species and communities relies in large part on identifying the underlying ecological mechanisms at work.…”

The Beringian Coevolution Project: holistic collections of mammals and associated parasites reveal novel perspectives on evolutionary and environmental change in the North

“…BCP collections are helping us to understand the implications of climate change for species distributions and community diversity (e.g., Baltensperger and Huettmann 2015;Hope et al 2015) and to monitor fundamental biological attributes such as life histories, life cycles, and parasite transmission dynamics (e.g., Kutz et al 2005;Jenkins et al 2006;Laaksonen et al 2015). For example, a series of discoveries based on field collections radically altered our understanding of the ungulate lungworm fauna in the Beringian region and broadly across the Holarctic (e.g., Hoberg et al 1995Hoberg et al , 2017Kutz et al 2001bKutz et al , 2007Jenkins et al 2005).…”

“…BCP collecting methods ensure the preservation of high-quality samples that permit investigations spanning broad spatial and temporal scales, including topics such as deep phylogenetic relationships Koehler et al 2009b;Lanier and Olson 2009;Esteva et al 2010;Haukisalmi et al 2010;Kohli et al 2014), the mode and timing of speciation (Hope et al 2011(Hope et al , 2013, community assembly and faunal mixing through time (Cook et al 2006;Galbreath andHoberg 2012, 2015;Hoberg et al 2012a;Cook and MacDonald 2013;Hope et al 2015), demographic responses to regional climate through interactions with major biotic and abiotic forces (e.g., Hope et al 2014), conservation implications of population fragmentation and expansion (Small et al 2003;Cook and MacDonald 2013;, recurrent gene flow (Runck et al 2009;Lindqvist et al 2010;Miller et al 2012;McLean et al 2016b), and isotopic investigations of dietary niche space (O'Brien et al 2017). Museum specimens lend themselves to integrated approaches to science, especially sample-intensive fields of study that now are experiencing rapid technological and methodological advances (stable isotopes, disease ecology, and predictive modeling: McLean et al 2016a;Dunnum et al 2017).…”

“…First, museums house considerable primary data (e.g., species identity, date of collection, georeferenced collection locality, and standard measurements) that can immediately inform biodiversity assessments and form the basis for predictive models of the future (Hope et al 2013(Hope et al , 2015. Second, as specimens and the sampling they represent are used in future investigations, large amounts of new or derivative data (e.g., genomes, stable isotopes, morphometric data, or parasite-host associations) become associated with the specimen record and can be readily accessed by research communities.…”

Alpine glacial relict species losing out to climate change: The case of the fragmented mountain hare population (Lepus timidus) in the Alps

“…SDMs extrapolate current species‐habitat associations to future environmental conditions so that potential changes in species distributions can be forecast. This allows to develop and implement targeted conservation measures for the benefit of the focal species (Bollmann & Braunisch, ; Braunisch et al., ; Hope et al., ).…”