Predicting diversity of juvenile neotropical fish communities: patch dynamics versus habitat state in floodplain creeks

Abstract

The species richness of communities should largely depend on habitat variability and/or on habitat state. We evaluated the ability of habitat variability and habitat state to predict the diversity of juvenile neotropical fish communities in creeks of a river floodplain. The young-fish fauna consisted of 73 taxa, and samples were well distributed over a wide range of relevant temporal and spatial habitat variability. We were unable to demonstrate clear patterns of richness in relation to temporal and spatial habitat variability (if habitat state variables were not included), regardless of the temporal variability scale, the grouping of sites (up- and downstream sites differed in temporal variability patterns), taxonomic units or life stages considered. Using stepwise multiple regression, 36% of the variance in species richness was explained for all data, and at best 47% was explained for all taxonomic units at upstream sites using temporal and spatial habitat variability and habitat state (bank length, mean width, mean water level before fishing and/or water turbidity). Using Monte Carlo simulations, we blindly predicted 31% (all data) and at best 37% (all upstream taxa) of the observed variance in species richness from these model types. This limited precision is probably because rare species produced most of the richness patterns in our creeks. The prediction of these rare species is generally difficult for various reasons, and may be a problem in many ecosystem types.

Density-range size relationships in French riverine fishes

“…Nevertheless, if this latter hypothesis fully applies to our dataset, then we should also expect an influence of body size on range size at the inter-basin scale (NRB), which is not the case. As it is well known that migration plays a role in the local dynamics of freshwater fishes (Horwitz 1978;Osborne and Wiley 1992;Grossman et al 1998;Mérigoux et al 1999;Oberdorff et al 2001b;Taylor and Warren 2001), another hypothesis consists of considering body size a surrogate for species dispersal ability. A resultant prediction is that more dispersive species (larger fishes in our case) should have wider distributions than less dispersive species of the same local density.…”

Community assembly at the patch scale in a species rich tropical river

“…Recent research, however, on fish assemblage structure in the Amazon River (Cox-Fernandez 1999;Petry et al 2003) and floodplain lakes of the Orinoco River (Rodrı`guez and Lewis 1997) has identified non-random fish assemblage structure in relation to physical environmental features that vary at the landscape scale. Using multiple regression analysis with a suite of variables indicating habitat states and variability, Me´rigoux et al (1999) were able to explain only a relatively small percentage of variance of fish species richness in lowland creeks in French Guiana. They attributed much of the unexplained variation to a strong influence of rare species.…”

Effects of within‐patch habitat structure and variation on fish assemblage characteristics in the Bernecei stream, Hungary

“…Much of the inference regarding the relative importance of biotic and abiotic factors in structuring stream fish assemblages has focused on whether a variety of assemblage properties (e.g., species richness, fish density, absolute or relative abundances) are stable or highly variable over ecologically significant temporal and spatial scales . Disagreement is present among researchers, because both variable and stable stream fish assemblages exist, although the former have been recorded from at least four continents (Grossman et al 1990;Przybylski 1994;Hugueny et al 1995;Matthews 1998;Oberdorff et al 1998Oberdorff et al , 2001Merigoux et al 1999).…”