Dispersal strength determines meta-community structure in a dendritic riverine network

作者：Canedo Argueelles Miguel^*; Boersma Kate S; Bogan Michael T; Olden Julian D; Phillipsen Ivan; Schriever Tiffany A; Lytle David A

来源：Journal of Biogeography, 2015, 42(4): 778-790.

DOI：10.1111/jbi.12457

• Arizona
• aquatic invertebrates
• connectivity
• dendritic networks
• dispersal
• distance decay relationship
• drought
• landscape resistance
• meta-community

AimMeta-community structure is a function of both local (site-specific) and regional (landscape-level) ecological factors, and the relative importance of each may be mediated by the dispersal ability of organisms. Here, we used aquatic invertebrate communities to investigate the relationship between local and regional factors in explaining distance decay relationships (DDRs) in fragmented dendritic stream networks.
LocationDryland streams distributed within a 400-km(2) section of the San Pedro River basin, south-eastern Arizona, USA.
MethodsWe combined fine-scale local information (flow and habitat characteristics) with regional-scale information to explain DDR patterns in community composition of aquatic invertebrate species with a wide range of dispersal abilities. We used a novel application of a landscape resistance modelling approach (originally developed for landscape genetic studies) that simultaneously assessed the importance of local and regional ecological factors as well as dispersal ability of organisms.
ResultsWe found evidence that both local and regional factors influenced aquatic invertebrate DDRs in dryland stream networks, and the importance of each factor depended on the dispersal capacities of the organisms. Local and weak dispersers were more affected by site-specific factors, intermediate dispersers by landscape-level factors, and strong dispersers showed no discernable pattern. This resulted in a strongly hump-shaped relationship between dispersal ability and landscape-level factors, where only moderate dispersers showed evidence of DDRs. Unlike most other studies of dendritic networks, our results suggest that overland pathways, using perennial refugia as stepping-stones, might be the main dispersal route in fragmented stream networks.
Main conclusionsWe suggest that using a combination of landscape and local distance measures can help to unravel meta-community patterns in dendritic systems. Our findings have important conservation implications, such as the need to manage river systems for organisms that span a wide variety of dispersal abilities and local ecological requirements. Our results also highlight the need to preserve perennial refugia in fragmented networks, as they may ensure the viability of aquatic meta-communities by facilitating dispersal.

• 出版日期2015-4