Global diversity patterns in sandy beach macrofauna: a biogeographic analysis.

Francisco Rafael Barboza,Omar Defeo

doi:10.1038/srep14515

Abstract

Unlike the advances generated on land, the knowledge of global diversity patterns in marine ecosystems is limited to a small number of studies. For sandy beaches, which dominate the world’s ocean shores, previous meta-analyses highlighted the role of beach morphodynamics in explaining species richness patterns. Oceanographic variables and historical processes have not been considered, even though they could be main predictors of community structure. Our work, based on 256 sandy beaches around the world, analysed species richness considering for the first time temperature, salinity and primary productivity. Biogeographic units (realms, provinces and ecoregions) were used to incorporate historical factors in modelling processes. Ecoregions, which implicitly include isolation and coastal complexity among other historical geographic factors, best represented trends in species richness worldwide. Temperature was a main predictor of species richness, which increased from temperate to tropical sandy beaches. Species richness increased with tide range and towards wide beaches with gentle slopes and fine grains, which is consistent with the hypothesis that habitat availability has an important role in structuring sandy beach communities. The role of temperature and habitat availability suggests that ocean warming and sea level rise could affect the distribution of obligate species living in these narrow ecosystems.

Highlights

Zones than in sub-tropical, warm temperate and cold temperate ones[12,13]
Species richness increased with temperature (Fig. 3d), highlighting the greatest richness exhibited by tropical sandy beaches
Our analyses demonstrate the central role of beach morphodynamics and temperature

Summary

Introduction

Zones than in sub-tropical, warm temperate and cold temperate ones[12,13]. Surprisingly, the role of sea surface temperature, sea surface salinity ( on referred to as temperature and salinity) and primary productivity has not been quantitatively considered in the explanation of global diversity patterns in these ecosystems, even though they have been indicated as main predictors of biogeographic structure and species richness for coastal and shelf benthic marine groups[7,14]. 4) The Habitat Availability Hypothesis, as formulated for sandy shores[13,23], which states that increasing tide range (defined as the vertical difference between the high tide and the succeeding low tide, and used here as a proxy for habitat availability) positively influences species richness. To this end, we analysed the macrofaunal species richness information from more than 250 sandy beaches around the world (Fig. 1), using Generalized Additive Mixed Models (GAMM) and Generalized Linear Mixed Models (GLMM). Provinces and ecoregions defined in the Marine Ecoregions of the World (MEOW) nested system[16] as random intercepts, in an effort to account for potentially different signatures of evolutionary history among biogeographic units

Methods

Results

Conclusion