A commentary (‘matters arising’) led by Marek and contributed to by a number of glacier ecologists has been published in Nature Ecology & Evolution, in response to a recent meta-analysis of global biodiversity responses to deglaciation. The authors of the original study compiled hundreds of primary studies and found increases in the abundance and richness of ‘generalist’ taxa in glacier-adjacent habitats, as well as a decline in ‘specialists’, following glacier retreat, and concluded that biodiversity increases locally as glaciers recede. Glaciers themselves were largely considered as abiotic agents and their intrinsic biodiversity ignored, while only glacier-adjacent habitats were reported for their changes in biodiversity.
However, it is now widely accepted that glaciers and ice sheets comprise unique habitats that host distinctive organisms and metabolically active populations that form communities, and facilitate key connections to neighbouring ecosystems, all of which may be severely altered, reduced, or lost upon deglaciation. The lack of data on glacial ecosystems in a global synthesis of biodiversity responses to glacier retreat is a warning sign that the biodiversity of glacial habitats is still largely unquantified, overlooked by the broader ecology community, and likely underestimated. This is especially worrisome given the magnitude of glacial habitat loss anticipated this century.
Upon deglaciation glacial ecosystems will likely be replaced by more diverse non-glacial systems. However, true glacier specialists will disappear, thus negatively impacting total biodiversity at regional scales. Moreover, the shared sensitivity of glacial and glacier-affected biodiversity to climate warming, as well as the interactions between glacial and glacier-adjacent ecosystems means these environments cannot be disentangled and, when possible, should not be considered in isolation. Given the vast, irreversible threat to glacial biodiversity on global scales, we urge the research community to not overlook glacial biodiversity and advocate for an integrative view of ecological changes in glaciated regions. Thus, we contend that a global synthesis of biodiversity responses to glacier retreat must include glacial ecosystems.
Stibal M, Bradley JA, Edwards A, Hotaling S, Zawierucha K, Rosvold J, Lutz S, Cameron KA, Mikucki JA, Kohler TJ, Šabacká M, Anesio AM (2020) Glacial ecosystems are essential to understanding biodiversity responses to glacier retreat. Nature Ecology and Evolution doi: 10.1038/s41559-020-1163-0