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Anthropogenic factors and habitat complexity influence biodiversity but wave exposure drives species turnover of a subtropical rocky inter‐tidal metacommunity 
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下载免费PDF全文 Coastal ecosystems are complex and species rich, but are vulnerable to degradation from a variety of anthropogenic activities. Nevertheless, information on inter‐tidal community composition in the Caribbean Basin and at other oceanic sites is lacking. Such information is essential to developing a more comprehensive understanding of rocky inter‐tidal systems and their responses to global change. The goals of this study were to determine the relative importance of environmental (wave power density, wave height), habitat (e.g. algal cover, slope, complexity of rock surfaces) and anthropogenic (distance to roads, population density) factors associated with the structure of local assemblages at multiple shore heights and the regional metacommunity of mobile invertebrates on oceanic rocky inter‐tidal habitats. Environmental characteristics associated with habitat complexity (algal cover, rock surface complexity) and human population density were most strongly associated with abundance and biodiversity of invertebrates. Species richness was positively correlated with surface complexity, but abundance was negatively correlated with both surface complexity and per cent algal cover. By contrast, abundance of invertebrates was positively correlated with human population density, and diversity was negatively correlated with human population density. Abundance of invertebrates was greatest in the mid inter‐tidal zone, whereas diversity was greatest in the lower inter‐tidal zone. Metacommunity structure was Gleasonian, but the gradient along which species turnover occurred was correlated with measures of wave exposure, rather than anthropogenic activity. Unlike in previous studies, mostly at mainland sites, human activity primarily altered dominance patterns of communities, while having relatively little effect on species richness or composition. 相似文献
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Erik E. Cordes Marina R. Cunha Joëlle Galéron Camilo Mora Karine Olu-Le Roy Myriam Sibuet Saskia Van Gaever Ann Vanreusel & Lisa A. Levin 《Marine Ecology》2010,31(1):51-65
Cold seeps are among the most heterogeneous of all continental margin habitats. Abiotic sources of heterogeneity in these systems include local variability in fluid flow, geochemistry, and substrate type, which give rise to different sets of microbial communities, microbial symbiont-bearing foundation species, and associated heterotrophic species. Biogenic habitats created by microbial mats and the symbiotic species including vesicomyid clams, bathymodiolin mussels, and siboglinid tubeworms add an additional layer of complexity to seep habitats. These forms of habitat heterogeneity result in a variety of macrofaunal and meiofaunal communities that respond to changes in structural complexity, habitat geochemistry, nutrient sources, and interspecific interactions in different ways and at different scales. These responses are predicted by a set of theoretical metacommunity models, the most appropriate of which for seep systems appears to be the 'species sorting' concept, an extension of niche theory. This concept is demonstrated through predictable patterns of community assembly, succession, and beta-level diversity. These processes are described using a newly developed analytical technique examining the change in the slope of the species accumulation curve with the number of habitats examined. The diversity response to heterogeneity has a consistent form, but quantitatively changes at different seep sites around the world as the types of habitats present and the size-classes of fauna analyzed change. The increase in beta diversity across seep habitat types demonstrates that cold seeps and associated biogenic habitats are significant sources of heterogeneity on continental margins globally. 相似文献
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《Limnologica》2020
We collected quantitative macroinvertebrate samples and measured environmental and geographical parameters at 13 sites: six along the main stem and seven in tributaries close to the main channel over a 700 m gradient in altitude and 22 km longitudinal distance along the River Kokra in the Slovenian Alps. Our objectives were 1) to compare longitudinal patterns in richness and community composition between main stem and tributary sites, and 2) to determine the relative importance of the replacement and richness difference component for overall beta diversity and of environmental versus spatial distance on beta diversity among main stem and tributary sites.In total 138 taxa were identified. There were no differences between main stem and tributary sites in mean abundance or taxon richness (67 and 58, respectively). A nMDS and ANOSIM based on Bray-Curtis similarities found no separation of main stem and tributary sites, but that upper (≥880 m a.s.l) and lower sites (≤680 m a.s.l.) formed two different groups. In both main stem and tributaries taxon richness increased only slightly going downstream while the community composition (DCA1) was much better explained by altitude and distance from source.Overall, beta diversity (Sørensen and Bray-Curtis dissimilarity) was similar for the two groups, and total Sørensen dissimilarity was driven mainly by replacement in main stem (78 %) and tributary sites (77 %). Mantel tests showed that main stem dissimilarities were significantly correlated to environmental PCA distance, watercourse distance, overland distance and altitudinal differences. Tributary dissimilarities were not correlated to any of these four factors. GLMs showed that dissimilarity among main stem sites was explained only by altitude difference, while no factors were significant among tributary sites, even though nearly so for environmental PCA distance.The study illustrates the importance of measuring beta diversity along ecological gradients, such as river continua and/or altitudinal gradients, where alpha diversity may fail to detect relatively minor changes in assemblage composition. Such changes are likely to occur due to present and future climate warming. 相似文献
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A number of isolated islands of Leymus chinensis + herbosa community were investigated in fragmented habitat islands, by Braun-Blanquet field survey approach, in a degenerated
meadow in the Songnen Plain, China in 2007. These islands were classified as large, medium, and small scales on the basis
of the island area (100–1000m2, large island; 50–100m2, middle island; 10–50m2, small island). Each scale of the investigation involved eight islands. The responses of β-diversity patterns of plant taxon to the habitat fragmentation at local community and metacommunity levels were analyzed
on different scales of 24 isolated islands. The results indicated that at the local community level, there were 57 species
belonging to 20 families and 49 genera in large islands, 49 species belonging to 16 families and 40 genera in middle islands,
and 27 species belonging to eight families and 23 genera in small islands. β-diversity indexes for species, genus and family in large, middle, and small islands varied greatly, and the highest value
of the indexes was not noted in the largest island. However, the average of the data obtained at the three scales showed that
across large islands, Whittaker indexes were low and Bray-Curtis similarity indexes were high, while across small islands,
Whittaker indexes were high and Bray-Curtis similarity indexes were low. At the metacommunity level, Whittaker indexes for
species and genus showed a great significantly negative double logarithmic correlation (p<0.01) with the island area, whereas the Bray-Curtis indexes for species, genus and family showed a great significantly positive
double logarithmic correlation (p<0.01) with the island area. At both local community and metacommunity levels, turnovers of species and genus could respond
more sensitively to spatial changes of plant diversity patterns than that of family. Hence, the species and the genus could
be used for the analysis of β-diversity patterns of plant community. 相似文献
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