ISSN:
1365-2427
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
〈list xml:id="l1" style="custom"〉1Ostracods occurring at two sections of the Upper Rhône River, France, were examined to determine relationships among species traits, habitat utilization, the relationship between species traits and habitat utilization, and trends in species traits and species richness in the context of spatial and temporal variability of habitats. Twenty regularly sampled species were used in this study and fifteen species traits were considered.2Throe groups can be distinguished according to their species traits: group 1 has species of mixed sizes with high reproductive rates, short life span, spherical shape, long swimming bristles, low thigmotactism, and high resistance to desiccation; group 2 has medium-sized species with low reproductive rates, long life span, low or no tolerance to desiccation, geometric (trapezoidal, triangular) or streamlined carapace shape, no swimming bristles, and a strong thigmotactism; group 3 has the largest species with parthenogenetic reproduction, medium-sized swimming bristles, and flattened or cylindric carapace shape.3Ostracod habitat utilization segregates the superficial and interstitial habitats along a gradient from the main channel to the abandoned arms and to the temporary waters.4The co-structure (= relationship) between species traits and habitat utilization indicates that the species use particular habitats with a particular set of species trait modalities. Species with long life spans, late maturity, low fecundity, and low migratory ability are restricted to the interstitial habitats; the epigean species with long life spans, large size, and parental care are more abundant in permanent flowing and standing surface waters; the epigean species with short life spans, high migratory ability, and high tolerance to desiccation are more abundant in temporary ponds.5The analyses of the distribution of the species traits in a river habitat templet of spatial and temporal variability emphasized that the main disturbance structuring the Rhône River ostracod assemblage is desiccation.6Of the trends predicted for species traits in the framework of the river habitat templet, five (size, body form, attachment, reproductive technique, and mobility) are clearly opposite for ostracods (because the predictions were mainly established for flood-related disturbances) but four (life span, number of reproductive cycles per year, age at first reproduction, and desiccation tolerance) are in agreement.7No trends in ostracod species richness in the framework of spatial–temporal habitat variability were evident.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1365-2427.1994.tb01745.x
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