Biology ETDs

Publication Date

Summer 7-28-2026

Abstract

The Little Colorado River (LCR) spinedace persists only in three isolated watersheds within the LCR Basin in Arizona. This imperiled minnow faces ongoing pressure from habitat alteration, climatic shifts, and invasive non-native predators. Over the past two decades, managers have translocated spinedace within watersheds to increase abundance and expand habitat occupancy. We sequenced a reference genome and analyzed single nucleotide polymorphisms (SNPs) from 475 individuals over their geographic range. DNA samples were obtained from a previous study in the mid-1990s and compared with samples from 2024 and 2025, allowing us to track genetic diversity, effective population size, population structure, and selection over roughly 30 years. Overall, genetic diversity remained stable. However, levels of genetic divergence among lineages indicate continued isolation and potential local adaptation, thus warranting management as distinct Evolutionarily Significant Units (ESUs). This study provides guidance on genetic mixing that could benefit declining populations, but without disrupting locally adapted gene pools. Our findings provide a genomic framework to aid in conservation decisions as managers seek to recover the LCR spinedace.

Project Sponsors

U.S. Bureau of Reclamation

Language

English

Keywords

genetics, conservation, fisheries, Little Colorado River, Lepidomeda vittata

Document Type

Thesis

Degree Name

Biology

Level of Degree

Masters

Department Name

UNM Biology Department

First Committee Member (Chair)

Dr. Thomas Turner

Second Committee Member

Dr. Megan Osborne

Third Committee Member

Dr. Michael Anderson

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