Blowin’ in the wind: Wind directionality affects wetland invertebrate metacommunities in Patagonia

Abstract

Aim: To assess the relative importance of wind intensity and direction in explaining wetland invertebrate metacommunity organization. Location: Seventy-eight wetland ponds in Patagonia (Argentina) covering a study area of 3.5 × 105 km2. Time period: Ponds were sampled once between 2006 and 2014. Major taxa studied: One hundred and fifty-eight taxa of wetland aquatic invertebrates. Methods: We generated two beta diversity matrices (based on flying and non-flying invertebrates) and six predictor matrices, including three environmental distance matrices, a topographic distance between ponds, and two wind pairwise matrices differing in wind speed. Using Moran spectral randomization of Mantel (MSR-Mantel) tests (which account for spatial autocorrelation), we assessed the relationship between the response and the predictor matrices. We used a network-constrained version of the nestedness metric based on overlap and decreasing fill (NODF), to assess if wind anisotropy (i.e., direction-dependent) affected community nestedness among ponds. Results: Flying dispersers’ dissimilarity was significantly explained by environmental variables, whereas non-flying invertebrates’ dissimilarity was not significantly explained by any of the distances tested. When wind direction was ignored, wind speed had a negligible effect on both types of communities, whereas when it was considered a consistent nested pattern emerged, with the eastern ponds (downwind) communities being subsets of those from the western ponds (upwind). Main conclusions: We found that the invertebrate communities were mainly assembled by a combination of environmental factors and wind directionality, although this depended on the dispersal ability of the organisms.