Title
Extreme Conservation Confronting Species Losses at the Edges of the World.
Author(s)
Berger, Joel; Hartway, Cynthia
Published
2017
Abstract
Declining glacial and sea ice is often accompanied by altitudinal and northward expansion of animals. Rapid changes in cold, snow, and drought regimes create uncertainty about the persistence of cold-adapted species. Here we examine how alteration of abiotic factors affects the biology of two extreme but unrelated species at the distal edges of their ranges – wild yaks and muskoxen, each averse to deep snow. Based on empirical field data gathered by non-invasive photogrammetry spanning eight years at three sites in the Russian and Alaskan Arctic, we assessed how drought and repeated minor rainon-snow events (ROS) affect skeletal growth in juvenile muskoxen (N=781). An increase in ROS events during gestation retarded maturation for up to three years. Our unanticipated finding of a growth handicap in body size reveals one mechanism by which changing climes affect this Arctic-adapted species. Further, we asked how the sexes of wild yaks above 5000 m on the Tibetan Plateau respond to changes in peri-glacial environments, and used data from three winter expeditions spanning a decade. Females on average were 5 kms closer to glaciers, and their densities twenty times greater at tiny snow patches than males in mid-winter. Knowing why these differences occurred would not have been possible without fieldwork which revealed females lactated despite ambient temperatures to negative 30oC; hence, increasingly patchy snow– not ice – substituted as sources for water to support milk production. Findings from our respective projects underscore the importance of combining field data with modeling and remote sensing to to understand mechanisms that may dictate alterations of species biology as landscapes change. Yet, despite the growing reality of climate burden, if we do not react to the immediacy of human impacts and their associated conflicts with wildlife, we will fail to conserve iconic species that define the northern remote and extreme elevations.
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PUB26866