Climate change and alpine stream biology: progress, challenges, and opportunities for the future

Abstract

In alpine regions worldwide, climate change is dramatically altering ecosystems and affecting biodiversity in many ways. For streams, receding alpine glaciers and snowfields, paired with altered precipitation regimes, are driving shifts in hydrology, species distributions, basal resources, and threatening the very existence of some habitats and biota. Alpine streams harbour substantial species and genetic diversity due to significant habitat insularity and environmental heterogeneity. Climate change is expected to affect alpine stream biodiversity across many levels of biological resolution from micro- to macroscopic organisms and genes to communities. Herein, we describe the current state of alpine stream biology from an organism-focused perspective. We begin by reviewing seven standard and emerging approaches that combine to form the current state of the discipline. We follow with a call for increased synthesis across existing approaches to improve understanding of how these imperiled ecosystems are responding to rapid environmental change. We then take a forward-looking viewpoint on how alpine stream biologists can make better use of existing data sets through temporal comparisons, integrate remote sensing and geographic information system (GIS) technologies, and apply genomic tools to refine knowledge of underlying evolutionary processes. We conclude with comments about the future of biodiversity conservation in alpine streams to confront the daunting challenge of mitigating the effects of rapid environmental change in these sentinel ecosystems.

Congruent population genetic structure but differing depths of divergence for three alpine stoneflies with similar ecology and geographic distributions

“…Comparative population genetic studies are rare in alpine streams (Hotaling, Finn, et al, 2017;Hotaling, Hood, et al, 2017;Hotaling, Tronstad, et al, 2017), and of the few that have been conducted, the majority have emphasised comparisons of ecologically distinct but co-occurring species, with hypothesised links between patterns of genetic differentiation and dispersal ability or other biological traits that influence gene flow (Dussex, Chuah, & Waters, 2016;Monaghan, Spaak, Robinson, & Ward, 2002).…”

“…Hotaling, Finn, et al, 2017;Hotaling, Hood, et al, 2017;Hotaling, Tronstad, et al, 2017;Jacobsen & Dangles, 2017;Wilhelm, Singer, Fasching, Battin, & Besemer, 2013). Hotaling, Finn, et al, 2017;Hotaling, Hood, et al, 2017;Hotaling, Tronstad, et al, 2017;Jacobsen & Dangles, 2017;Wilhelm, Singer, Fasching, Battin, & Besemer, 2013).…”

“…Hotaling, Finn, et al, 2017;Hotaling, Hood, et al, 2017;Hotaling, Tronstad, et al, 2017;Morelli et al, 2016). However, only a conservation plan developed for Z. glacier across its range would also protect both Lednia species.…”

“…Endangered Species Act due to climate change-induced loss of alpine glaciers and permanent snowfields (U.S. Fish and Wildlife Service, 2016). Linked to these changes is the potential loss of entire communities of meltwater-dependent alpine organisms Hotaling, Finn, Giersch, Weisrock, & Jacobsen, 2017;Hotaling, Hood, & Hamilton, 2017;Hotaling, Tronstad, & Bish, 2017;Muhlfeld et al, 2011) and, in most cases, little to no 5. Linked to these changes is the potential loss of entire communities of meltwater-dependent alpine organisms Hotaling, Finn, Giersch, Weisrock, & Jacobsen, 2017;Hotaling, Hood, & Hamilton, 2017;Hotaling, Tronstad, & Bish, 2017;Muhlfeld et al, 2011) and, in most cases, little to no 5.…”

Microbial assemblages reflect environmental heterogeneity in alpine streams

“…Streams above the tree line in the alpine zone exhibit substantial environmental heterogeneity over small spatial scales, due in large part to variable hydrological sources (Brown, Hannah, & Milner, 2007;Füreder, 2007;Hotaling, Finn, Giersch, Weisrock, & Jacobsen, 2017;Ward, 1994). With such extensive habitat diversity, it is no surprise that alpine streams also support high among-stream (β) diversity across multiple taxonomic scales and classifications, including macroinvertebrate species diversity (Brown et al, 2007;Finn, Bonada, Murria, & Hughes, 2011;Giersch, Hotaling, Kovach, Jones, & Muhlfeld, 2016;Jacobsen, Milner, Brown, & Dangles, 2012), macroinvertebrate genetic diversity (Finn, Khamis, & Milner, 2013;Finn, Zamora-Muñoz, Múrria, Sáinz-Bariáin, & Alba-Tercedor, 2014;Hotaling et al, 2019;Jordan et al, 2016;Leys, Keller, Räsänen, Gattolliat, & Robinson, 2016), and microbial diversity (Fegel, Baron, Fountain, Johnson, & Hall, 2016;Freimann, Bürgmann, Findlay, & Robinson, 2013a;Wilhelm, Singer, Fasching, Battin, & Besemer, 2013).…”