Spatio‐temporal patterns of fish assemblage structure in a coastal plain stream: appropriate scales reveal historic tales

Abstract

Quantifying assemblage structure across spatio-temporal scales is ecologically important and further aids in the understanding of community organisation processes. Currently, few studies have assessed assemblage structure across generous magnitudes of scale, and influences of processes (biotic and abiotic) responsible for structuring assemblages are still questioned. Using community and hydrologic data collected over a 22-year period from a stretch of river nearing 150 km, we examined spatio-temporal fish assemblage structural patterns in a temperate coastal plain stream. Results indicated that significant changes in assemblage structure across time were influenced by environmental disturbances, including drought and hurricane events. Assemblages were restructured in a punctuated manner directly following these events, and complete recovery of initial assemblage structure did not occur across the study period. Additionally, we found spatial differentiations between upstream and downstream assemblages, which were driven by greater abundances of several species in downstream sites. Our results suggest that assemblage structure is influenced by environmental variation, specifically, extreme disturbance events and spatial habitat heterogeneity.

Temporal and spatial dynamics of fish community structure during watershed alteration in two Ouachita River systems

“…Other stream systems that have incurred substantial hydrologic alteration, loss of connectivity, and drought have experienced more drastic changes in fish community composition (Etnier, Starnes, & Bauer, 1979;Geheber & Piller, 2012;Gido et al, 2010;Perkin et al, 2014) compared to the Saline River basin.…”

“…Although there were likely some differences in sampling techniques across collectors, common in studies examining temporal patterns (e.g., Patton, Rahel, & Hubert, 1998;Geheber & Piller, 2012), we employed measures to minimise variation in sampling methods as much as possible (e.g., discussions Despite seeing changes in fish community composition and functional dissimilarity through time, the Saline River basin still has a unique ichthyofauna and future conservation efforts should advocate for the preservation of one of the longest unregulated rivers in Arkansas. We likely did not detect all changes as watershed alteration occurred prior to historical surveys, and we were unable to infer patterns of rare species (e.g., Alabama shad [Alosa alabamae] and P. uranidea).…”

“…In upland stream systems with natural disturbances (e.g., flood and drought) and minimal anthropogenic disturbance, fish communities exhibit "loose equilibrium" through time by fluctuating in composition, but never deviating away from normal bounds of community structure in multivariate space (Matthews & Marsh-Matthews, 2016). Stream fish communities that are resilient can endure short-term anthropogenic perturbations such as chemical spills with only a brief "hangover effect" (Piller & Geheber, 2015), but chronic perturbations such as drought and watershed alteration can exceed ecological thresholds and shift community structure to an alternative state (Geheber & Piller, 2012;Gido, Dodds, & Eberle, 2010;Perkin, Troia, Shaw, Gerken, & Gido, 2014). The response of fish communities to landscape alterations is highly variable due to the covariation of natural and anthropogenic gradients, multi-scale mechanisms, nonlinear responses and land use legacies (Allan, 2004).…”

Spatial and seasonal dynamics of fish assemblage along river Soan, Pakistan and its relationship with environmental conditions

“…Changes in water flow affect river depth, substrate composition and epifaunal cover. Variations in hydrological conditions particularly during drought condition affect fish assemblage structure either due to loss of habitat or decline in water quality (Geheber and Piller, 2012).…”

Temporal dynamics of stream fish assemblages and the role of spatial scale in quantifying change

“…However, relatively few studies have evaluated the influence of spatial scale variation on temporal dynamics of communities (Fuhlendorf & Smeins, 1996;Sirami, Brotons, & Martin, 2008), to say nothing of aquatic communities. Most of those examining fish assemblages specifically did not deal with spatial scale per se, but rather longitudinal gradients (i.e., stream hierarchy; Schlosser, 1982) differences among habitats (Bart, 1989) or among areas within a system (Geheber & Piller, 2012). The studies that have explicitly considered spatial scale typically compare two scales: "local" and "global" (Collins, 2000).…”