Climate Change, Ecosystem Processes and Biological Diversity Responses in High Elevation Communities

Abstract

The populations, species, and communities in high elevation mountainous regions at or above tree line are being impacted by the changing climate. Mountain systems have been recognized as both resilient and extremely threatened by climate change, requiring a more nuanced understanding of potential trajectories of the biotic communities. For high elevation systems in particular, we need to consider how the interactions among climate drivers and topography currently structure the diversity, species composition, and life-history strategies of these communities. Further, predicting biotic responses to changing climate requires knowledge of intra- and inter-specific climate associations within the context of topographically heterogenous landscapes. Changes in temperature, snow, and rain characteristics at regional scales are amplified or attenuated by slope, aspect, and wind patterns occurring at local scales that are often under a hectare or even a meter in extent. Community assemblages are structured by the soil moisture and growing season duration at these local sites, and directional climate change has the potential to alter these two drivers together, independently, or in opposition to one another due to local, intervening variables. Changes threaten species whose water and growing season duration requirements are locally extirpated or species who may be outcompeted by nearby faster-growing, warmer/drier adapted species. However, barring non-analogue climate conditions, species may also be able to more easily track required resource regimes in topographically heterogenous landscapes. New species arrivals composed of competitors, predators and pathogens can further mediate the direct impacts of the changing climate. Plants are moving uphill, demonstrating primary succession with the emergence of new habitats from snow and rock, but these shifts are constrained over the short term by soil limitations and microbes and ultimately by the lack of colonizable terrestrial surfaces. Meanwhile, both subalpine herbaceous and woody species pose threats to more cold-adapted species. Overall, the multiple interacting direct and indirect effects of the changing climate on high elevation systems may lead to multiple potential trajectories for these systems.

Forecasting climate change response in an alpine specialist songbird reveals the importance of considering novel climate

“…Importantly, the upward elevational shift of predicted high habitat suitability may not necessarily correspond to a similar scale of actualized range contraction. A key factor that may mitigate climate change risks for alpine species, especially in the Rocky Mountains, is the highly heterogeneous topography of the alpine landscape (Seastedt & Oldfather, 2021). Alpine microtopography can result in thermal refugia along short horizontal distances that mimic air temperature changes of hundreds of meters upslope (Scherrer & Körner, 2010).…”

“…Global climate change is dramatically affecting biodiversity, and extinction rates are accelerating across taxonomic groups (Urban, 2015). Alpine organisms that already inhabit the upper elevational reaches can be at particular risk of climate change driving upslope range shifts due to reduced potential to shift their range (Freeman et al, 2018; Sekercioglu et al, 2008); however, this risk may be tempered in regions that provide an abundance of microclimates (Seastedt & Oldfather, 2021). If range shift is not feasible, a species' long‐term persistence in the face of climate change will likely depend on evolutionary or behavioural adaptation (Aitken et al, 2008; Forester et al, 2018; Hoban et al, 2016; Hoffmann & Sgró, 2011).…”

Biodiversity and ecology of plants and arthropods on the last preserved glacier of the Apennines mountain chain (Italy)

“…This biodiversity seems to be related to the biogeographic position of Calderone glacier and its role as a refugium for high-altitude species. In the current climate scenario of temperature increase, which threatens cold-adapted species (Seastedt et al, 2021), it is important to study the ecology of these environmental units in order to monitor glacial "cold-spots" of biodiversity, since an important part of this biodiversity is still taxonomically unknown, especially in peripheral mountains (Gobbi et al, 2021). Only in this way it will be possible to hypothesize also a monitoring and, possibly, a conservation strategy, as well as to forecast the global future patterns and the fate of glacial biodiversity.…”

Low-Altitude Boundary of Abies faxoniana Is More Susceptible to Long-Term Open-Top Chamber Warming in the Eastern Tibetan Plateau

“…The Effects of Altitude and Long-Term Warming on Soil Nutrients Different altitudes at small geographic scales, such as subalpine ranges, exhibit steep climatic gradients with decreasing temperature (Seastedt and Oldfather, 2021). Forest soil properties differ greatly across altitudes.…”