Patterns and habitat associations of a desert spring fish assemblage and responses to a large-scale flood
Date
2006-08
Authors
Watson, Jacqueline M.
Journal Title
Journal ISSN
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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). <i>Patterns and habitat associations of a desert spring fish assemblage and responses to a large-scale flood</i> (Unpublished thesis). Texas State University-San Marcos, San Marcos, Texas.