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Biodiversity of soft‐sediment benthic communities from Italian transitional waters
Author(s) -
Munari Cristina,
Mistri Michele
Publication year - 2008
Publication title -
journal of biogeography
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.7
H-Index - 158
eISSN - 1365-2699
pISSN - 0305-0270
DOI - 10.1111/j.1365-2699.2008.01919.x
Subject(s) - species richness , benthic zone , ordination , ecology , alpha diversity , biodiversity , gamma diversity , geography , beta diversity , ecoregion , community structure , species diversity , diversity index , biology
Aim For conservation purposes, it is important to understand the forces that shape biodiversity in transitional waters (TWs) and to evaluate the effects of small‐scale latitudinal changes. To this end, we analysed data on soft‐sediment macroinvertebrates from nine Italian TWs in order to (1) investigate the structure and distribution of the benthic fauna and their relationships with environmental and geographical variables, and (2) examine species richness and β‐diversity at various spatial scales. Location European Transition Waters Ecoregion 6. Methods Using a data set collected along a 7° latitudinal cline between 45°28′ N and 39°56′ N, we used Spearman’s rank correlation analysis to evaluate the relationships between species richness and both environmental and geographical variables, and linear regression analysis to show the relationships between α‐, β‐ and γ‐diversity. Three measures were used to assess β‐diversity: Whittaker’s β W, and two similarity indices, namely the Bray‐Curtis similarity index and Δ s . Using multivariate analyses, we determined the similarity in composition of the benthic community between sites and compared the biotic ordination with abiotic (geographical and environmental) characteristics. Results Two hundred and sixty‐eight species were recorded from 46 sites. Of these, 53.4% were restricted to one TW. Annelida was the dominant taxonomic group, followed by Crustacea and Mollusca. The α‐diversity was highly variable (5–87 species) and was correlated with latitude. The γ‐diversity, measured at the TW scale, was correlated significantly with α‐diversity. The β‐diversity increased with spatial scale and habitat heterogeneity. In the community pattern identified by multivariate analysis, TWs were segregated by latitude and biogeography, and this reflected different climatic conditions. Main conclusions We found that α‐diversity increased when moving from higher to lower latitudes, and that it depended on both regional and local factors. In addition, we detected latitudinal variations in the extent of regional influence on local species richness. The observed distribution pattern of TW faunas depended mostly on climate type. We suggest that the distribution of annelidan species could be used as a proxy for assessing general community patterns for Italian TWs.