Patterns and habitat associations of a desert spring fish assemblage and responses to a large-scale flood
Date
2006-08
Authors
Watson, Jacqueline M.
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Abstract
I examined the spatial and temporal patterns and habitat associations of a desert spring fish assemblage from 2002 to 2005 in the minimally impacted Independence Creek drainage, a tributary of the Pecos River. During the third year, a large flood event (2,245 m3/s) inundated lower reaches of Independence Creek (mean discharge =1.7 m3/s). The flood transformed the heavily vegetated, heterogeneous and slightly incised stream channel to a shallower, monotypic stream without streamside vegetation. Preflood Independence Creek consisted of 65% of spring endemic fishes, 24% of generalist fishes, and <1% of species common in the Pecos River. Environmental parameters explained 44% (P<0.05) of the fish assemblage variation. Among spring endemics, multivariate ordination plots indicated strong habitat associations for Etheostoma grahami (riffle habitats) and ubiquitous habitat associations for Cyprinella proserpina, Dionda episcopa and Notropis amabilis. Post-flood Independence Creek consisted of 83% spring endemic fishes, 12% of generalist fishes, and 2% of species common in the Pecos River. Absolute and relative abundances of generalist fishes decreased attributed to downstream displacement. Absolute and relative abundances of Pecos River fishes increased attributed to habitat alterations (i.e., shallower depths, warmer water temperatures) within Independence Creek. Spring endemics were unaffected by the flood. Post-flood, multivariate fish-habitat associations shifted predictably from generally deeper habitats with silt and instream cover to shallower and slightly swifter habitats in side channels and riffles with gravel. However, the spatial arrangement among fishes was similar between preflood and post-flood distributions suggesting that spring endemics are highly resilient to perturbation. Information from this study will be used to manage and protect Independence Creek habitats and species of conservation concern, and to establish restoration standards in degraded spring-fed tributaries of the Rio Grande.
Description
Keywords
ecology, fishes, stream animals
Citation
Watson, J. M. (2006). Patterns and habitat associations of a desert spring fish assemblage and responses to a large-scale flood (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.