Date of Graduation

5-2021

Document Type

Thesis

Degree Name

Master of Science in Biology (MS)

Degree Level

Graduate

Department

Biological Sciences

Advisor/Mentor

Douglas, Michael E.

Committee Member

Douglas, Marlis R.

Second Committee Member

Limp, Fredrick W. Jr.

Keywords

Aquatic biodiversity; Climate change; Habitat loss; Himalaya; Schizothorax; Snowtrout; Species distribution model

Abstract

Monitoring biodiversity, to include its relative dispersal and contraction, has become a conservation task of great importance, particularly given the catastrophic and ongoing loss of habitat due to climate change. However, the timing, direction, and magnitude of these rates vary across taxa and ecosystems. Predicting specific impacts of climate change can thus be difficult and this, in turn, hampers management action. Metrics are needed to not only quantify contemporary requirements of species, but also predict potential distributions that fluctuate in lockstep with climate.

Montane ecosystems in the Himalayas are highly impacted by climate change, yet remain largely understudied due to the harsh nature of their terrain. Riverine ecosystems are particularly vulnerable in this regard, as annual reductions in snow cover and rainfall will impair hydrologic discharge. This, in turn, places Himalayan aquatic biodiversity at the forefront of climate change.

In response, I developed Ecological Niche Models (ENMs) for two Himalayan fishes (Snowtrout: Family Cyprindae, Schizothorax richardsonii, S. prograstus) distributed broadly across the Himalaya. Each ENM evaluates species occurrence data, as derived from in-depth literature surveys and field sampling. These data, together with 19 bioclimatic, physiographic, and hydrologic variables, were then evaluated using Generalized Linear Modelling (GLM). Results, as gauged by relative Area Under Curve (AUC) values, indicate both study species are currently resident within western and eastern components of the Himalaya. Future predictions, based on bioclimatic variables, indicate potential expansion into higher elevations of the central Himalaya as the regional climate elevates substantially.

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