Biology ETDs

Publication Date

Summer 7-28-2025

Abstract

Streambed drying naturally occurs in over 60% of rivers and streams worldwide. Climate change and human regulation of surface and groundwater have increased drying in naturally intermittent systems and caused perennial systems to transition to intermittency, impacting water security, water quality, and biodiversity. To understand human-induced drying dynamics, we used 12 years of daily drying data along a 154-km regulated reach of the Rio Grande. We conceptualized river drying as a regime analogous to the natural flow regime paradigm and quantified drying magnitude, rate of change, and duration. Although linear models predicting drying magnitude and rate of change were uninterpretable, drying duration was best predicted at the smallest (7 km subreach) scale. Ecologically, drying magnitude was the strongest predictor of autumn fish assemblages, during late-summer and early-autumn drying. Complexity analyses suggested that drying dynamics exhibited nonlinear determinism, informing managers about relevant spatial scales, critical thresholds, and periods for effective management.

Language

English

Keywords

Complexity, flow intermittency, fish assemblage, Rio Grande

Document Type

Dissertation

Degree Name

Biology

Level of Degree

Doctoral

Department Name

UNM Biology Department

First Committee Member (Chair)

Dr. Thomas Turner

Second Committee Member

Dr. Melanie Moses

Third Committee Member

Dr. Alex Webster

Fourth Committee Member

Dr. Helen Wearing

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