Geostatistical analysis of horizontal distributions of zooplankton biomass and environmental variables in a small lake during the spring season
On the basis of a dense sampling survey, and for a given site and a given season (Lake Nantua; mid-spring), we assessed on which scales the spatial patterns of the biocenosis and its environment were most strongly expressed. These preliminary results focused on global descriptors (total biomass per surface unit, means computed from vertical multiprobe recordings). The theoretical variograms fitted to the data showed that most of the total variance was expressed on a broad scale for total zooplankton biomass. In contrast, the variance of descriptors reflecting lake metabolic processes was expressed on very short scales. For most of the explored descriptors, their relations with temperature also varied dramatically on a spatial scale, supporting the hypothesis that distinct structural factors prevail at different scales. The practical implications of these multiscale characteristics are discussed.