Broad-scale patterns in local diversity of marine benthic harpacticoid copepods (Crustacea)

摘要

The α and β diversity of benthic harpacticoids were estimated using 103 published datasets from all over the world, with depths ranging from the intertidal zone to 5600 m. a diversity (expected number of species per 100 individuals) was correlated with organic matter flux to the bottom, and this effect was depth-dependent, with the correlation being negative from the shallowest waters up to 33 m and positive in deeper waters, α diversity was also positively correlated with depth itself and depended on the sediment properties and duration of study, but showed no latitudinal trend. β diversity (estimated as the slope of the species accumulation curve) was negatively correlated with latitude and positively correlated with the spatial extent and depth range of sampling. The effect of latitude and extent was mainly pronounced for the intertidal zone, whereas the depth range was the most significant factor in the deep waters. Additionally, β diversity was higher on sands and mixed sediments than on silt or mud. Latitude explained 45 % of the β diversity variation in the littoral zone, 18% in the upper sublittoral, and less than 5% in deeper zones. Thus, a and β diversity act as independent and spatially uncorrelated components of overall regional diversity, driven by different mechanisms. Variations in β diversity presumably reflect spatial heterogeneity and form the latitudinal gradient in the shallowest waters. Deeper, trophic conditions play the leading role, and thus a diversity contributes the major proportion of the total diversity variance there and is responsible for the bathymetric gradient.