科研之友
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摘要
We assessed the potential influence of hydrological connectivity among subdrainages on the structural and functional organization of stream macroinvertebrate metacommunities in 2 adjacent, large Asian watersheds (similar to 1.4 million km(2)). To examine the structural organization of metacommunities, we used multisite beta-diversity partitioning and applied the Elements of Metacommunity Structure (EMS) framework to resolve aspects of taxon associations and metacommunity assembly. We also decomposed functional diversity into nestedness and turnover to assess functional organization of metacommunities among watersheds of contrasting connectivity. To describe changes in functional composition, we used a multidimensional functional trait analysis to calculate the 3 primary components of functional diversity. The nestedness component of beta diversity had a higher contribution in the watershed displaying isolated subdrainages, and apparent lack of hydrological connectivity had a significant effect on the ecological fitting of macroinvertebrate metacommunities, generating a discrete composition of communities. Partitioning of functional b diversity suggested no difference among watersheds in metacommunity functional organization and a high level of functional redundancy among communities of subdrainages independent of hydrological isolation. These results show that hydrological connectivity is potentially an important driver structuring stream macroinvertebrate metacommunities at a macroecological scale. Patterns of metacommunity structure were expressed better using taxonomic than functional-trait diversity. In spite of a perceived functional redundancy, a wider functional space was observed in the absence of hydrological connectivity, a result suggesting discrete but partially overlapping functional entities associated with hydrological isolation in these watersheds.
- 出版日期2018-3
