Exploring Freshwater Fish Biodiversity in Bhutan through Species Distribution Models: A Case Study on Snowtrout

Abstract

Conservation and biodiversity management are focal points for the United Nations Convention on Biological Diversity (CBD). However, monitoring agencies in participating nations that supply data are now severely hampered by political/economic constraints, with “data-deficient” species as a result. This issue will only grow as Himalayan glaciers wane, monsoons shift/diminish, and available freshwaters decline due to climate change. Habitat for cold-water native fishes will shrink while non-natives pre-adapted to warmer, disturbed habitats sharply increase. Effects will be most apparent in countries like Bhutan, where legislation exists to actively conserve/protect biodiversity yet with freshwater fishes recognizably data-deficient, a management issue that must be quickly adjusted, given rapid climate change. Yet, what are the best strategies to accomplish this? And how might they be implemented/sustained as climate change intensifies? This study demonstrates a potential approach by deriving a Species Distribution Model (SDM) for two putative and three unidentified Bhutanese snowtrout (Cyprinidae; Schizothorax spp.), using limited occurrence/distribution data collected by National Research & Development Centre for Riverine & Lake Fisheries (NRDCR&LF, MoAF, Haa). Two influential niche parameters were identified: Seasonal precipitation and annual temperature range, both actively being revised by climate change. Surprisingly, preferred snowtrout habitat is broadly distributed across midelevations of Bhutan, supporting the presence of recognized but “unidentified” forms (i.e., datadeficient). Additional long-term monitoring is needed to compensate for these deficiencies and to manage snowtrout as climate-driven impacts alter riverine flows. Both are immediate requirements for the conservation of Bhutan’s freshwater biodiversity.