Browsing by Author "Fairchild, Matthew, committee member"

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Open Access
Estimating the population size and distribution of the Arapahoe snowfly (Arsapnia arapahoe) (Plecoptera: capniidae) along the northern Front Range of Colorado
(Colorado State University. Libraries, 2015) Belcher, Thomas Paul, III, author; Kondratieff, Boris, advisor; Vieira, Nicole, committee member; Coleman, Robert, committee member; Fairchild, Matthew, committee member
The population size and geographic distribution of the recently described Arapahoe snowfly, Arsapnia arapahoe (Nelson and Kondratieff) (Plecoptera: Capniidae) is unknown. Prior to this study, A. arapahoe was known only from two tributaries of the Cache la Poudre River in Larimer County, Colorado, Young Gulch and Elkhorn Creek. The objectives of this study were to determine the distribution of A. arapahoe along the northern Front Range of the Rocky Mountains in Colorado, to estimate the abundance of adult A. arapahoe in Elkhorn Creek (the stream with the largest known population), and to identify co-occurring sympatric species as possible surrogate indicators of its presence. I also investigated the potential effects of wildfire and flood disturbance on known populations of the Arapahoe snowfly. To determine the distribution in other Front Range streams, I sampled 54 streams for A. arapahoe in 2013 and 2014, several of which were chosen based on GIS modeling for potential suitable habitats. I also conducted an intensive depletion sampling study in three 300-m segments of Elkhorn Creek (n=5 reaches per segment) using quantitative beat sheet techniques. Sampling was estimated to capture over 90% of available adult individuals, and 100% of A. arapahoe individuals. Thus population size estimates could be obtained. Further, adults of A. arapahoe were only discovered in six additional, first-order streams outside the original type localities in Cache la Poudre River Basin. New species localities were discovered in three additional drainage basins: Big Thompson River, St. Vrain River, and Boulder Creeks. Intensive sampling efforts in Elkhorn Creek revealed substantially low abundances of A. arapahoe adults (only 10 individuals found in the duration of the study), justifying the designation of this species as a rare taxon. Two sympatric species, A. decepta (Banks) and Capnia gracilaria Claassen, were consistently found with A. arapahoe, and thus may serve as a future indicator of suitable stream habitat. Both A. arapahoe and associated species appeared to be adversely impacted by post-wildland fire erosion and sediment deposition; however, capniids, including A. arapahoe, appeared to be resilient to flooding. I present suggestions for continued monitoring of the presence, abundance and distribution of A. arapahoe for conservation of this rare and endemic Colorado stonefly.
Embargo
Riverscape features and isolation-by-distance shape spatial genetic structure of Brook Trout in a Colorado headwater stream network
(Colorado State University. Libraries, 2024) Stack, Taylor, author; Kanno, Yoichiro, advisor; Winkelman, Dana, advisor; Oyler-McCance, Sara, committee member; Fairchild, Matthew, committee member; Funk, William Chris, committee member
Understanding the influences of riverscape characteristics on gene flow in stream networks is crucial for managing population connectivity in freshwater species. In this study, we examined the fine-scale genetic structure of non-native Brook Trout (Salvelinus fontinalis) in a headwater stream network proposed for future reintroduction of native trout. Using 12 microsatellite loci, we genotyped 757 individual Brook Trout from 22 sampling sites throughout the dendritic stream network and modelled the effects of physical riverscape features on gene flow. Genetic clustering analysis identified four distinct tributary groups, indicating fine-scale population structure, while pairwise genetic differentiation estimates (mean FST = 0.04; mean Jost's D = 0.06) revealed some genetic connectivity across the network. Riverscape genetics models identified vertical barriers and steep stream gradients as key factors impeding gene flow, whereas higher order mainstem streams were more conducive to trout movement. Gene flow was stronger in the downstream direction, and models with interaction terms revealed that asymmetries between upstream and downstream gene flow were more pronounced in stream reaches with barriers and steep gradients. Mantel tests confirmed that both waterway distance between sites and riverscape resistance significantly influence genetic connectivity across the network. Overall, this study demonstrates that spatial genetic patterns in stream networks are shaped by a combination of isolation-by-distance, riverscape resistance, and asymmetric stream flow. Our findings suggest that this reintroduction area provides sufficient genetic connectivity to support a metapopulation of native trout.