Site-specific distribution of the bivalve Scrobicularia plana along the European coast

Abstract

The development and maintenance of spatial patterns and the way they affect the dynamics of populations and ecosystems is a key issue in ecology. Since each individual and each species experiences the environment on a unique range of scales, it is vital to determine the spatial scales across which organisms interact with each other and the structuring influence of their environments, which can be achieved by analyzing species' distribution patterns. Here, the spatial variation in the distribution of Scrobicularia plana is described for 4 intertidal areas along the species' distributional range. Spatial autocorrelation correlograms based on Moran's coefficient reveal that while the Trondheim (Norway) population was randomly distributed, at Minho (Portugal), the Westerschelde, and the Wadden Sea (both in The Netherlands) populations were aggregated. Patch diameter varied from 150 to 1250 m, in Minho and Westerschelde, respectively; while in the Wadden Sea, patches of 4 to 10 km were detected. Comparisons of spatial patterns with those of other co-occurring bivalve species (Abra tenuis, Cerastoderma edule, and Macoma balthica) revealed that S. plana's distribution was generally patchier. The distribution of S. plana was correlated with sediment type at Westerschelde and Trondheim, but not Minho. The observed differences in distribution patterns and their correlation with environmental factors reveal that spatial patterns of S. plana are site-specific rather than species-specific.

The clam Neilonella sulculata in San Jorge Gulf (Argentina, Southwest Atlantic): spatial distribution pattern and inverse relationship between size and density

“…Spatial autocorrelation may be induced by a causal relationship with another spatially autocorrelated variable (Fortin et al 2002). Spatial distribution patterns in infaunal bivalves have been analysed with regard to a range of environmental factors such as depth, sediment characteristics, hydrodynamics, and availability of food to deposit feeders (Legendre et al 1997;Morsan 2003;Santos et al 2011Santos et al , 2012.…”