engleski

Functional versus taxonomic information as predictors of spatiotemporal variation in a macrofaunal community in a seagrass mosaic

Functional diversity, the range and variety of functional traits possessed by species in a community, may be positively associated with numerous ecosystem processes ; however, debate continues over the relative information value of taxonomic versus functional trait identity in predicting and explaining these processes, especially in highly diverse communities such as seagrass meadows, the most biodiverse shallow marine ecosystem in Europe. We monitored abundance of juvenile and adult benthic and demersal macrofauna over a 12-month period, day and night, across 40 km of transects over 10 sampling stations within a shallow mosaic of seagrass, bare sediment, rock, and macroalgal habitas in the Novigrad Sea, Croatia, using DGPS/videographic SCUBA visual census. We quantified over 90 functional traits, each defined as a separate node in a binary tree, in observed macrofauna. We found that the most powerful predictor of overall spatiotemporal abundance variation across all habitats, stations, seasons, and diel was the taxonomic genus, which explained 66% of all absolute or relative variation. In contrast, each functional node explained about 3% of the overall abundance variance ; thus, a minimum of 20 nodes was necessary to provide the same predictive power as taxonomic genus. Genus explained 64%, 85%, 76%, and 68% of relative seasonal, diel, habitat, and station abundance of fish respectively (significantly for diel and habitat), while the most informative functional dimension, reproductive mode, explained 16%, 21%, 27%, and 12% of these abundance components (significantly for habitat only). We conclude that taxonomic identity contains unique ecological information not contained in popular categories of functional identity.

fish community; Adriatic; functional; phylogeny

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