Spatial and temporal patterns in fish assemblages of upper coastal plain streams, Mississippi, USA

Abstract

We assessed spatial, seasonal, and annual variation in fish assemblages over 17 months in three small-to medium-sized, incised streams characteristic of northwestern Mississippi streams. We sampled 17 962 fish representing 52 species and compared assemblages within and among streams. Although annual and seasonal variability in assemblage structure was high, fish assemblages maintained characteristics unique to each stream. High variability in fish catch-per-unit-effort (CPUE) was exemplified in one site where total CPUE increased an order of magnitude from July 1993 to 1994. Species turnover and percent dissimilarity were often higher seasonally than annually, consistent with a period of change in spring to early summer and a return to similar species compositions between summers. Temporal variability was also high at the individual species level, and no species were classified as 'stable'. We found little evidence for correlation between changes in fish assemblage structure and measured habitat conditions. The fish characteristics fit the profile of 'colonizing assemblages', which probably resulted from both natural and anthropogenic causes. Flashy hydrographs, created in part by stream channelization and incision and watershed deforestation, may play a large role in structuring these fish assemblages. Extreme interannual variability in assemblages in the absence of detectable habitat change has important implications for the statistical power of fish monitoring programs designed to detect trends in fish assemblages over time.

Seasonal and diel variation in the fish assemblage of a Neotropical delta in southern Brazil

“…This pattern is similar to that observed in other areas with subtropical climates (JAUREGUIZAR et al, 2003;ADAMS et al, 2004).…”

Genetic effects of habitat fragmentation and population isolation on Etheostoma raneyi (Percidae)

“…This altered stream gradients which resulted in stream incisement and headcutting in nearly all headwater streams (Shields et al 1998). Channelized and incised streams tend to be shallow, sandy, homogeneous, turbid, and unstable with flashy flows (Shields et al 1994(Shields et al , 1998Simon and Darby 1997;Adams et al 2004).…”

Short-term decompositional state does not influence use of wood by macroinvertebrates in subtropical, coastal plain streams

“…Kaller & Kelso (2006) proposed that broad tolerances of stream invertebrates to dissolved oxygen and woody debris manipulations were the result of generalist life histories arising from both habitat stochasticity and filtering of coastal plain colonist invertebrates during fluctuating sea levels over evolutionary time. Similarly, Adams et al (2004) and Williams et al (2005) recognized habitat stochasticity could affect fish and invertebrate community composition by promoting generalism. Therefore, for a variety of potential reasons, these coastal stream invertebrates may be generalist users of any type of woody debris.…”