THEORETICAL HABITAT TEMPLETS, SPECIES TRAITS, AND SPECIES RICHNESS - FLOODPLAIN VEGETATION IN THE UPPER RHONE RIVER

1. The floodplain vegetation at approximately 100 sites located in nin e different habitat types of the Upper Rhone River, France, was survey ed three times over the past 27 years. Information on species traits o f the higher plants comprising the Rhone floodplain vegetation was bas ed on studies conducted between Geneva, Switzerland, and Lyon, France. 2. These data were structured using a 'fuzzy coding' technique and th en examined using ordination analyses to investigate: (i) relationship s among species traits; (ii) habitat utilization; (iii) the relationsh ip between species traits and habitat utilization; and (iv) trends of species traits and species richness in the framework of,spatial-tempor al habitat variability to test predictions of the river habitat temple t and the patch dynamics concept. 3. Size, number of descendants per r eproductive cycle, number of reproductive cycles per individual, and t he regeneration potential of an individual were positively related wit h each other, whereas the degree of attachment to the soil decreased, and the reproductive period shifted from autumn/late summer towards ea rly summer/spring, as size increased. 4. The habitat utilization by th e higher plants of the floodplain revealed a double lateral gradient: the first was from the banks of the temporary waters to terrestrial fl ats; the second from aggrading pebble to aggrading silt habitats. Thes e gradients were related to gradients in water saturation, oxygen cond itions, nutrient loading, and nutrient retention of the soils. 5. A si gnificant relationship between species traits and habitat utilization was observed for the floodplain vegetation, i.e. plant communities use d particular habitat types with a particular set of species trait moda lities (= categories). 6. Patterns of species trait modalities were si gnificantly related to temporal and spatial habitat variability but on ly modalities of the trait 'parental care' conformed to trends predict ed from theory. 7. No trends were observed when species richness of di fferent habitat types was considered in the framework of spatial-tempo ral habitat variability. 8. Although the habitats of the Upper Rhone c learly act as a templet for the species traits of the floodplain veget ation, the lack of agreement between observations and predictions on t rends in species traits and richness in terms of habitat variability s uggest that important elements of theory should be rejected. However, human-induced changes in these habitats are too recent when compared w ith the longer time periods required for floodplain vegetation to resp ond to such changes.