Date of Award

2024-05-01

Degree Name

Master of Science

Department

Geology

Advisor(s)

Elizabeth J. Walsh

Abstract

Desert ecosystems present challenges for aquatic organisms as habitats are fragmented, both in space and time; however, diapausing stages of rotifers can travel hundreds of kilometers during wind events. I used the rotifer Euchlanis chihuahuaensis as a model species to investigate the influence of wind dispersal on gene flow and population genetics in Chihuahuan Desert populations. I hypothesized that anemochory facilitates gene flow from source populations in the Northern Chihuahuan Desert in Mexico and the western United States to habitats in the Trans-Pecos region via delineated wind corridors. To test this hypothesis, the genetic diversity of populations from both inside and outside of the wind corridors were compared. The corridors were constructed using data from modeled HYSPLIT trajectories of dust events over 40 years. Genetic variation in the COI gene among populations from inside and outside of the dust corridor were analyzed to determine possible isolation by distance, fixation (FST), and haplotype distributions. My results provided limited evidence for gene flow from populations from Southern New Mexico with individuals with shared haplotypes occurring in non-hydrologically connected habitats between 100 â?? 200 km apart; however, many discrete haplotypes were identified which belonged to single sites or local areas. My results elucidated the population structure of E. chihuahuaensis, with three haplogroups identified with discrete geographic boundaries in Southern New Mexico, Trans Pecos, and the Mexican border area in northern Chihuahua state, along with the identification of a putative cryptic species. Regionally partitioned populations indicated that "West" (Mimbres River Delta Region -PLP) and "East" (IMRS) regions had higher levels of haplotype diversity ranging from 0.85 to 0.93. Limited evidence points to genetic differences in diversity from populations located both inside and outside the dust corridor (58% among and 42% within populations). Investigating anemochoryâ??s role in gene flow in desert environments can help us further understand evolutionary and ecological processes in aquatic microinvertebrates inhabiting ephemeral systems.

Language

en

Provenance

Received from ProQuest

File Size

111 p.

File Format

application/pdf

Rights Holder

Tristan Chavez-Poeschel

Download

Share

COinS