| Abstract | Niche and neutral processes drive community assembly and metacommunity dynamics, but their relative importance might vary with the spatial scale. The contribution of niche processes is generally expected to increase with increasing spatial extent at a higher rate than that of neutral processes. However, the extent to what community composition is limited by dispersal (usually considered a neutral process) over increasing spatial scales might depend on the dispersal capacity of composing species. To investigate the mechanisms underlying the distribution and diversity of species known to have great powers of dispersal (hundreds of kilometres), we analysed the relative importance of niche processes and dispersal limitation in determining beta-diversity patterns of aquatic plants and cladocerans over regional (up to 300 km) and continental (up to 3300 km) scales. Both taxonomic groups were surveyed in five different European regions and presented extremely high levels of beta-diversity, both within and among regions. High beta-diversity was primarily explained by species replacement (turnover) rather than differences in species richness (i.e. nestedness). Abiotic and biotic variables were the main drivers of community composition. Within some regions, small-scale connectivity and the spatial configuration of sampled communities explained a significant, though smaller, fraction of compositional variation, particularly for aquatic plants. At continental scale (among regions), a significant fraction of compositional variation was explained by a combination of spatial effects (exclusive contribution of regions) and regionally-structured environmental variables. Our results suggest that, although dispersal limitation might affect species composition in some regions, aquatic plant and cladoceran communities are not generally limited by dispersal at the regional scale (up to 300 km). Species sorting mediated by environmental variation might explain the high species turnover of aquatic plants and cladocerans at regional scale, while biogeographic processes enhanced by dispersal limitation among regions might determine the composition of regional biotas. Ecography |
| Text | 386271 2016 10.1111/ecog.01231 Scopus 2 s2.0 84959202677 Species turnover; Aquatic communities Assembly mechanisms determining high species turnover in aquatic communities over regional and continental scales Viana D.S.; Figuerola J.; Schwenk K.; Manca M.; Hobaek A.; Mjelde M.; Preston C.D.; Gornall R.J.; Croft J.M.; King R.A.; Green A.J.; Santamaria L. Estacion Biologica de Doñana EBD CSIC , C/Americo Vespucio, Sevilla, s/n, ES 41092, , Spain; Inst. for Environmental Sciences, Univ. of Koblenz Landau, Landau/Pfalz, DE 76829, , Germany; Biodiversity and Climate Research Centre BiK F , Senckenberganlage 25, Frankfurt am Main, DE 60325, , Germany; Netherlands Inst. of Ecology NIOO KNAW , Droevendaalsesteeg 10, PB Wageningen, NL 6708, , Netherlands; CNR Istituto per lo Studio degli Ecosistemi, Largo Tonolli 50, Verbania, IT 28922, , Italy; Norwegian Inst. for Water Research NIVA , Branch Office Bergen, Bergen, , Norway; Dept of Biology, Univ. of Bergen, Bergen, , Norway; Norwegian Inst. for Water Research NIVA , Gaustadalleen 21, Oslo, NO 0349, , Norway; Centre for Ecology and Hydrology, Wallingford, OX10 8BB, , United Kingdom; Dept of Biology, Univ. of Leicester, Leicester, LE1 7RH, , United Kingdom; College of Life and Environmental Sciences, Univ. of Exeter, Stocker Road, Exeter, EX4 4QD, , United Kingdom Niche and neutral processes drive community assembly and metacommunity dynamics, but their relative importance might vary with the spatial scale. The contribution of niche processes is generally expected to increase with increasing spatial extent at a higher rate than that of neutral processes. However, the extent to what community composition is limited by dispersal usually considered a neutral process over increasing spatial scales might depend on the dispersal capacity of composing species. To investigate the mechanisms underlying the distribution and diversity of species known to have great powers of dispersal hundreds of kilometres , we analysed the relative importance of niche processes and dispersal limitation in determining beta diversity patterns of aquatic plants and cladocerans over regional up to 300 km and continental up to 3300 km scales. Both taxonomic groups were surveyed in five different European regions and presented extremely high levels of beta diversity, both within and among regions. High beta diversity was primarily explained by species replacement turnover rather than differences in species richness i.e. nestedness . Abiotic and biotic variables were the main drivers of community composition. Within some regions, small scale connectivity and the spatial configuration of sampled communities explained a significant, though smaller, fraction of compositional variation, particularly for aquatic plants. At continental scale among regions , a significant fraction of compositional variation was explained by a combination of spatial effects exclusive contribution of regions and regionally structured environmental variables. Our results suggest that, although dispersal limitation might affect species composition in some regions, aquatic plant and cladoceran communities are not generally limited by dispersal at the regional scale up to 300 km . Species sorting mediated by environmental variation might explain the high species turnover of aquatic plants and cladocerans at regional scale, while biogeographic processes enhanced by dispersal limitation among regions might determine the composition of regional biotas. Ecography 39 Published version http //www.scopus.com/inward/record.url eid=2 s2.0 84959202677 partnerID=q2rCbXpz Articolo 2016_Ecography_39_281_288.pdf Articolo in rivista Blackwell 1600 0587 Ecography Online Ecography Online Ecography Online marinamarcella.manca MANCA MARINA MARCELLA |
