bluuebunny/crossref_metadata_2025_split huggingface dataset:
A fuzzy coding approach for the analysis of long‐term ecological data
Authors: CHEVENE FRANçOIS , DOLÉADEC SYLVAIN , CHESSEL DANIEL 
Published: May 2006

SUMMARY

We present an unconventional procedure (fuzzy coding) to structure biological and environmental information, which uses positive scores to describe the affinity of a species for different modalities (i.e. categories) of a given variable. Fuzzy coding is essential for the synthesis of long‐term ecological data because it enables analysis of diverse kinds of biological information derived from a variety of sources (e.g. samples, literature).
A fuzzy coded table can be processed by correspondence analysis. An example using aquatic beetles illustrates the properties of such a fuzzy correspondence analysis. Fuzzy coded tables were used in all articles of this issue to examine relationships between spatial‐temporal habitat variability and species traits, which were obtained from a long‐term study of the Upper Rhône River, France.
Fuzzy correspondence analysis can be programmed with the equations given in this paper or can be performed using ADE (Environmental Data Analysis) software that has been adapted to analyse such long‐term ecological data. On Macintosh AppleTM computers, ADE performs simple linear ordination, more recently developed methods (e.g. principal component analysis with respect to instrumental variables, canonical correspondence analysis, co‐inertia analysis, local and spatial analyses), and provides a graphical display of results of these and other types of analysis (e.g. biplot, mapping, modelling curves).
ADE consists of a program library that exploits the potential of the HyperCardTM interface. ADE in an open system, which offers the user a variety of facilities to create a specific sequence of programs. The mathematical background of ADE is supported by the algebraic model known as ‘duality diagram’.
Theoretical habitat templets, species traits, and species richness: aquatic oligochaetes in the Upper Rhône River and its floodplain
Authors: JUGET JACQUES , LAFONT MICHEL 
Published: May 2006

SUMMARY

This paper summarizes twenty years of ecological research on aquatic oligochaetes of the Upper Rhône River and its alluvial floodplain (France). Species traits of fifty species of the ninety taxa recorded from two areas Gons and Brégnier‐Cordon) were used to examine the relationships among species traits, habitat utilization of these species, whether a relationship exists between species traits and habitat utilization, and the applicability of predictions from the river habitat templet and the patch dynamics concept in the framework of spatial and temporal habitat variability. We used fourteen habitat types and sixteen species traits in this analysis.
When examined by correspondence analysis, species traits separate the Naididae (with a higher potential for reproduction, small size, high mobility, and opportunistic diet) from all other families.
Habitat utilization by oligochaetes demonstrates two gradients: a vertical gradient that arranges species by their affinity for interstitial habitats (stygophily) and a transversal gradient that arranges them by their affinity for main channel habitats (rheophily).
No significant relationship was found between species traits and habitat utilization in a co‐inertia analysis.
Trends observed for species traits within the framework of spatial‐temporal habitat variability show only minor agreement with predictions of the river habitat templet.
Species richness is generally higher in superficial and interstitial habitats that are permanently connected with the main channel, and peaks in the superficial parapotamons (backwaters that are permanently connected with the main channel) characterized by intermediate levels of spatial as well as temporal variability; this pattern only partially fits with predictions of the patch dynamics concept.
Theoretical habitat templets, species traits, and species richness: ostracods (Crustacea) in the Upper Rhône River and its floodplain
Authors: MARMONIER PIERRE , BODERGAT ANNE‐MARIE , DOLÉDEC SYLVAIN 
Published: May 2006

SUMMARYOstracods 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.Throe 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.Ostracod habitat utilization segregates the superficial and interstitial habitats along a gradient from the main channel to the abandoned arms and to the temporary waters.The 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.The 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.Of 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.No trends in ostracod species richness in the framework of spatial–temporal habitat variability were evident.
Theoretical habitat templets, species traits, and species richness: amphibians in the Upper Rhône River and its floodplain
Authors: JOLY PIERRE , MORAND ALAIN 
Published: May 2006

SUMMARY

The purpose of this study was to test predictions of the habitat templet and the patch dynamics concept by analysing the relationship between either the species traits or species richness of amphibians and the spatial–temporal variability of eight habitat types of the Upper Rhône River and its floodplain, France.
The information on species traits of the twelve amphibian species was accumulated primarily from the literature; that on habitat utilization was based on field surveys. The information was ‘fuzzy coded’, analysed by ordination techniques, and finally linked to the spatial–temporal variability of habitat types elaborated elsewhere in this issue.
After elimination of the variance caused by the differences between urodeles and anurans, correspondence analysis of the matrix of species traits demonstrated that the flexibility of the temporal pattern of reproduction was the major source of variation among amphibian species. A less significant source of variation within anurans was related to traits usually linked to the concept of r–K selection (potential number of descendants per reproductive cycle and ratio of egg size to female size).
A correspondence analysis of habitat utilization by amphibian species separated four groups of habitat types, corresponding to different degrees of influence that the active channel had on adjacent waters in the floodplain (i.e. from habitats that are most frequently disturbed by floods, to habitats of braided sections, old oxbow lakes, and the more terrestrialized habitats).
A co‐inertia analysis of the relationship between species traits and habitat utilization separated two habitat types (terrestrialized former meanders and oxbow lakes) from the others. Species of terrestrialized habitats had a reproductive display, a low number of descendants per reproductive cycle, and a high ratio of egg size to female size. Species of oxbow lakes were early or synchronous breeders, and laid a single clutch.
Neither the predictions of the habitat templet concept nor those of the patch dynamics concept were validated. Species traits were not significantly correlated to the axes of the spatial–temporal variability templet. The highest species richness was observed in habitat types with the highest temporal variability; in addition, richness did not peak at highest spatial variability.
Deviation from the predictions of the river habitat templet could be explained by: (i) the over‐simplification of this model with regard to the evolution of the complex life cycles of the amphibians; and (ii) an underestimation of the importance of phylogenetic constraints and the evolution of community interactions.
Native and exotic freshwater fishes in Spanish river basins
Authors: ELVIRA B. 
Published: May 2006

SUMMARY1. The degree to which fish faunas have been invaded by exotic species is quantified on the basis of river basins.2. Nineteen exotic species are now established in Spanish fresh waters. Alburnus alburnus (L., 1758) is reported here for the first time.3. The native/total fish ratio varies from 0.71 in Galicia, the best preserved fish fauna, to 0.41 in Douro, the most modified fish assemblage. The national average ratio (0.63) is similar to that reported for Portugal (0.65), but higher than that in Italy (0.56) and much lower than that in Greece (0.88).4. Exotic fishes have sometimes become successfully established over wide areas in a short time.
Freshwater amphipods as biomonitors of metal pollution in surface and interstitial aquatic systems
Authors: PLÉNET S. 
Published: May 2006

SUMMARY1. The relationships between levels of metals (Zn, Cu) in the environment (water, sediment) and in the tissues of three species of amphipod crustaceans were investigated in superficial and interstitial ecosystems of the Rivers Rhone and Ain, France.2. Epigean and hypogean amphipods differed in their ability to accumulate Zn and Cu. At all sites, Gammarus fossarum (epigean) showed lower Zn or Cu body concentrations than Niphargus of, rhenorhodanensis or Niphargopsis casparyi (hypogean). Differences were also observed between the two interstitial taxa.3. A significant difference among sites was observed for metal concentrations in sediment. In contrast, no significant inter‐site differences were found for metal concentrations in organisms.4. No significant correlation was found between metal concentrations in the three taxa and quantities of metals in the water. A positive correlation was observed between Zn and Cu body content in Gammarus fossarum and metal level in the sediment. No relationships were found between interstitial amphipods and metal concentrations in the sediment.5. Differences in accumulation rates among the three amphipod species suggest their potential use as biological indicators for monitoring metal pollution.
The contribution of flood disturbance, catchment geology and land use to the habitat template of periphyton in stream ecosystems
Authors: BIGGS BARRY J.F. 
Published: May 2006

SUMMARY1. Periphyton chlorophyll a (chl a), ash‐free dry mass, taxonomic composition, and cellular and water‐column nutrients were analysed every 4 weeks for a year at sixteen stream sites in New Zealand. The hypothesis was investigated that broad‐scale differences in mean monthly periphyton development are defined primarily by the frequency of flood disturbances and the periphyton's interaction with the nutrients. it us of the streams as determined by catchment geology and land use.2. Overall, mean monthly chl a concentration declined with increasing flood frequency (r= ‐0.711, P < 0.001), and seasonality in chl a was better defined at sites with a low frequency of floods. Chlorophyll a concentration was generally low throughout the year at sites with frequent floods (> 15 yr−1).3. No relationship existed between inorganic nutrient concentrations and catchment geology or land development. However, conductivity declined significantly as a function of the percentage of the catchment underlain by nutrient‐poor, hard rocks (plutonic and fine‐grained metamorphic rocks) (r= ‐0.515, P < 0.05), but increased significantly with the percentage of the catchment in intensive agricultural land use (r= 0.799, P < 0.001).4. Cellular nutrient concentrations suggested that nitrogen was the nutrient most commonly limiting periphyton production. In turn, cellular N concentrations declined significantly with increasing percentage of the catchment in hard rock (r= ‐0.5M, P < 0.05) and increased with percentage of the catchments in intensive agricultlural land use (r= 0.948, P < 0.001).5.The sites were classified into three enrichment groups (high, moderate and low) based on their land use and underlying geology. Cellular N concentrations varied significantly among these enrichment groups (ANOVA F= 14.661, P < 0.001).6. Log chl a decreased significantly with increases in the annual 80th percentile velocity. However, the relationship was significantly different among the enrichment groups.7. A stepwise multiple regression on the full dataset identified that the frequency of floods, proportion of the catchment in high‐intensity agricultural land use and proportion in alkaline rocks were the most significant factors explaining variation in mean monthly chl a among the sites (r2= 89%).8. Overall, the results showed that flood disturbance and catchment enrichment regimes are probably the principal axes of the habitat template of periphyton among the study streams, and could be used to explain and predict broad‐scale differences in periphyton development among other temperate stream ecosystems.
The ordination of benthic invertebrate communities in the South Platte River Basin in relation to environmental factors
Authors: TATE C.M. , HEINY J.S. 
Published: May 2006

SUMMARY1. Spatial patterns of benthic‐invertebrate communities were examined in the 62 900 km2 South Platte River Basin in Colorado, Nebraska and Wyoming, U.S.A., to determine major environmental factors associated with invertebrate distribution. Stable substrates were sampled semiquantitalively for invertebrates from 27 July to 7 August 1992, at twenty‐one sites. Data on physical and chemical variables were collected concurrently at each site.2. Four site groups were identified using derrended correspondence analysis (DCA), one in the mountains and three in the plains (braided channels, tributaries near the confluence with the main stem, and sites affected by effluent from wastewater‐treatment plants). DCA axis 1 separated sites into the two major ecoregions (Southern Rocky Mountains and Western High Plains), and regression of DCA axis 1 with environmental variables indicated significant relationships primarily with slope, water temperature, specific conductance, and concentrations of organic nitrogen + ammonia and total phosphorus in surface water. Regression of DCA axis 2 with environmental variables indicated significant relationships with channel width and concentrations of nitrate + nitrite in surface water.3. Invertebrate community composition and structure varied between ecoregions with greater number of taxa and number of insect families in mountain streams than in plains streams. Within an ecoregion, land use affected the invertebrate community.4. Factors affecting invertebrate community distribution in stream ecosystems are scale dependent.
Long‐term dynamics of a freshwater sponge population
Authors: PRONZATO ROBERTO , MANCONI RENATA 
Published: May 2006

SUMMARY1. Quantitative field data were collected from a Sardinian population of the sponge Ephydutia fluvtatilis from 1987 to 1993 in order to study its life style.2. Growth of sponges was high during the annual cycle, and showed few changes in 6 years. Gemmulation was very rapid and highly efficient. Life spans of many specimens extended up to 5 years.3. The population was destroyed by one flood during our study period. The persistence of gemmules on substrata suggested that dispersal was low in our study population. Recolonization started 7 months after the flood and re‐established a new population, different from the previous one in terms of spatial structure and specimen size.
Effects of microspatial complexity on a herbivore—epilithon interaction in an Australian upland stream
Authors: GAWNE BENJAMIN , LAKE P. SAM 
Published: May 2006

SUMMARY1. Increases in spatial heterogeneity may provide more food, create new resources or interfere with the foraging activities of a herbivore.2. Three colonization experiments were performed in an upland stream to investigate the effects of one type of spatial heterogeneity (grooves on the substratum) on the relationship between an abundant herbivore, Agapetus monticolus (Banks, Trichoptera), and the epilithon on which it feeds.3. The results indicate that grooves do not provide any different resources or interfere with the foraging activities of A. monticolus, but may increase food abundance, although the effect of grooves on food abundance appears to vary temporally.4. Temporal variation in the effects of microspatial complexity raises the possibility that its importance to the community may be over‐ or underestimated unless experiments are designed to incorporate this temporal variation.
Randomness and aggregation: analysis of dispersion in an epiphytic chironomid community
Authors: TOKESHI MUTSUNORI 
Published: May 2006

SUMMARY1. Patterns of dispersion in a chironomid community on the submersed macrophyte Myriophyllum spicatum were analysed.2. Random dispersion commonly occurred throughout the year, with an average of 40% of all species being observed with random spatial patterns. The frequency of occasions with random dispersion varied among chironomid species, ranging from 3.3% in Rheotanytarsus curtistylus to 56% in Thienemanniella majuscula.3. Estimates of the negative binomial parameter k show that 26% of all cases demonstrate strong aggregation (0 < k < 1.0) while nearly half (47%) have quasi‐random dispersion. Interspecific variation in k was not significant statistically when all the species were considered together, although a pairwise comparison between two abundant species Tvetenia calvescens and Rheotanytarsus curtistylus demonstrated a marginally significant difference. When different instars were compared, the percentage frequency of strong aggregation (0 < k < 1.0) declined from first instars (49%) to later instars (II‐38%, III‐24% and IV‐27%).4. Variance/mean and m*—m regressions (m* is Lloyd's mean crowding statistic and m is the sample mean) both fitted the data well, but there was little indication of significant interspecific variation in parameter values, particularly the slope of regression.5. Dispersion patterns were examined along with the analysis of spatial overlap in this community. Forty‐two per cent of species‐pairs with reduced spatial overlap (spatially ‘segregated’ pairs) contained one or both species with random dispersion, while the corresponding value for spatially unsegregated pairs was 57%. This suggests that spatial segregation is not necessarily caused by strong, independent aggregation of both species. Comparing spatially segregated vs. unsegregated pairs, the former tend to have one species with a stronger tendency of aggregation than species of the latter.6. Patterns of dispersion observed were considered in the light of ‘random patch formation’. Random patch formation emphasizes the stochasticity of patch‐forming processes as well as the stochastically dynamic nature of resultant patches. Unlike terrestrial drosophilid assemblages, where strong aggregation is a predominant pattern, this chironomid community demonstrates widely varying degrees of dispersion with high occurrence of randomness, reflecting the stochasticity of dispersal and recolonization processes. It is suggested that, in terms of species coexistence, more emphasis should be placed on stochasticity rather than on aggregation in this type of community.
Phenotypic variation in metamorphosis in four species of freshwater copepods
Authors: TWOMBLY S. 
Published: May 2006

SUMMARY1. Physiological metamorphosis accompanied by an ecological habitat shift is a widespread life‐history phenomenon, and both age and size at metamorphosis are highly variable in many organisms. In this study, age and size at metamorphosis (defined as the transition from the last naupliar to the first copepodite stage) were quantified for four species of freshwater copepods to determine the scale on which these two traits vary, if age and size at metamorphosis are equally variable, and if variation at metamorphosis is related to variation in newborn size.2. Measurements of laboratory‐reared and field‐caught individuals show that age and size at metamorphosis, together with newborn size, vary among siblings, between families within a population, between populations of one species and between closely related species.3. In all populations, age at metamorphosis was the most variable trait, a result observed in many other organisms. Most of the variation in age at metamorphosis could be explained by differences between families within a population, while differences among siblings from the same clutch accounted for most of the variation in size at metamorphosis.4. Although newborn size was variable, differences in this trait could not fully account for variation observed at metamorphosis. Newborn size differed among populations, but most interpopularional differences disappeared by the rime metamorphosis was reached. In particular, size at metamorphosis appears to be tightly constrained in freshwater copepods.5. Age and size at metamorphosis were not equally variable among species, either. Species‐specific metamorphic envelopes (joint distributions of age and size at metamorphosis) result from differences in trait means, variances and covariances, and suggest very different larval growth trajectories among three of the species examined.
Life cycles and food habits of mayflies and stoneflies from temporary streams in western Oregon
Authors: DIETERICH MARTIN , ANDERSON N. H. 
Published: May 2006

SUMMARY1. Field data and results from laboratory rearing are combined to describe life cycles and food habits of the mayflies Paraleptophlebia gregalis and Ameletus n. sp., and the stoneflies Soyedina interrupts, Ostrocerca foersteri, Sweltsa fidelis and Calliperla luctuosa.2. P. gregalis, A. n. sp., S. interrupts and O. foersteri have univoltine life cycles which are characterized by a high degree of plasticity. S. fidelis and C. luctuosa have semivoltine life cycles which are more tightly synchronized.3. Laboratory feeding trials and field observations characterize P. gregalis as a collector, A. n. sp. as a scraper, O. foersteri and S. interrupta as shredders and C. luctuosa as a predator mainly of midge larvae. Late‐instar larvae of S. fidelis are believed to be scavengers.4. Laboratory rearing yielded a negative correlation between growth rates (Y) and larval size in autumn (X) for S. interrupta. This indicates compensatory growth by small larvae in order to achieve synchronized emergence. The correlation can be described by the equation: Y = 0.0053–0.0036X (R2= 0.82; P < 0.01; n = 22)5. The field and laboratory data indicate that photoperiod mainly determines the rate of development and size of emerging subimagos in P. gregalis.