Empirical studies on structuring mechanisms of metacommunities usually focus on the major roles of environmental filtering and dispersal. Recent works suggest that the relative importance of these structuring mechanisms differs among organisms with different body size, taxonomic affiliation, and dispersal abilities, and also depends on spatial extent and environmental heterogeneity. However, the effects of physical connectivity among sites and dispersal mode are less commonly considered explicitly in field metacommunity studies. We analysed a rock‐pool animal metacommunity, comparing both environmental and spatial effects between a set of pools in a ravine setting, with ephemeral connecting waterways, and another in a hill setting, without such connections. We also analysed the relative role of structuring mechanisms influencing active versus passive dispersers in the metacommunity. We used permutational multivariate analysis of variance and analysis of the multivariate homogeneity of group dispersions to compare environmental and species variation between landscape settings. Variation partitioning was applied to determine the percentage of species variation explained by environmental and spatial variables. The relative influence of the structuring mechanisms depended on both the landscape connectivity context and species dispersal mode. Species sorting drove active‐disperser metacommunities in both isolated and waterway connected pools, suggesting that these animals had a dispersal rate among the environmentally suitable sites that was adequate to compensate for extinctions at the spatial scale we considered. In addition, beta diversity of active dispersers and species‐sorting effects were higher in the set of ravine rock pools that were more environmentally heterogeneous and connected by waterways. In contrast, species sorting structured passive‐disperser metacommunities only in the set of pools with connecting waterways, whereas spatial constraints more strongly affected passive dispersers in the relatively more isolated hillside pools. Overall, environmental variables had a greater effect than spatial variables on rock‐pool metacommunities at the scale we studied, with the exception that passive dispersers in rock pools unconnected by waterways did tend to have spatially constrained distributions.

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A variety of organisms can colonize microplastic surfaces through biofouling processes. Heterotrophic bacteria tend to be the focus of plastisphere research; however, the presence of epiplastic microalgae within the biofilm has been repeatedly documented. Despite the relevance of biofouling in determining the fate and effects of microplastics in aquatic systems, data about this process are still scarce, especially for freshwater ecosystems. Here, our goal was to evaluate the biomass development and species composition of biofilms on different plastic polymers and to investigate whether plastic substrates exert a strong enough selection to drive species sorting, overcoming other niche‐defining factors. We added microplastic pellets of high‐density polyethylene (HDPE), polyethylene terephthalate (PET), and a mix of the two polymers in 15 lentic mesocosms in five different locations of the Iberian Peninsula, and after one month, we evaluated species composition and biomass of microalgae developed on plastic surfaces. Our results, based on 45 samples, showed that colonization of plastic surfaces occurred in a range of lentic ecosystems covering a wide geographical gradient and different environmental conditions (e.g., nutrient concentration, conductivity, macrophyte coverage). We highlighted that total biomass differed based on the polymer considered, with higher biomass developed on PET substrate compared to HDPE. Microplastics supported the growth of a rich and diversified community of microalgae (242 species), with some cosmopolite species. However, we did not observe species‐specificity in the colonization of the different plastic polymers. Local species pool and nutrient concentration rather than polymeric composition seemed to be the determinant factor defying the community diversity. Regardless of specific environmental conditions, we showed that many species could coexist on the surface of relatively small plastic items, highlighting how microplastics may have considerable carrying capacity, with possible consequences on the wider ecological context.

Human-mediated dispersal has rarely been considered in wetland conservation strategies at regional scales, yet high concern exists about this aspect for (inter-)national management considering invasive species in other aquatic systems. In this context, we aim at understanding the role of human-mediated dispersal by footwear in protected wetlands with high conservation value. Zooplankton and zoobenthos were sampled in 13 shallow lakes in central Spain and, at the same time, mud attached to waders was collected and later cultured in deionized water under laboratory conditions for 4 weeks. Two-hundred and four individuals belonging to 19 invertebrate taxa were recovered after hatching; Ostracoda (84 %), Cladocera (53 %), Copepoda (30 %), Anostraca (30 %), and Notostraca (7 %) were the most frequent groups among the hatched crustaceans. NMDS and PERMANOVA analyses showed significant differences between the dispersed (via footwear) and the source active metacommunity, suggesting different dispersal abilities among the species found. Human vectors facilitate dispersal among protected lakes, which could eventuality lead to biotic homogenization and faster spread of non-indigenous species. Preservation strategies and education campaigns associated to target humans in close contact with water bodies should be imperative in conservation management of protected lakes.

Desertification is a major environmental problem in arid and semiarid regions. Tree plantation has been commonly employed to foster the recovery of degraded areas. However, this technique is costly, and their outcomes are often uncertain. Therefore, we evaluated an alternative method for the restoration of degraded semiarid steppes that involved the construction of branch piles to attract frugivores as potential seed‐dispersing birds, promoting seed rain, and fostering the formation of woody patches. We measured the success of branch piles in terms of the number of bird visits and seed input compared to naturally occurring shrub patches. Generally, frugivorous birds visited branch piles less frequently than shrub patches. Yet, branch piles accumulated seeds of patch‐forming shrub species. Seed rain was higher under patches of the dominant shrub Rhamnus lycioides than under branch piles. In contrast, woody patches and branch piles did not differ in seed input of the less abundant Pistacia lentiscus shrub. Our study demonstrates that branch piles are used by frugivorous birds and accumulate seeds of patch‐forming shrubs. Branch piles may be a suitable method to promote the expansion of bird‐dispersed plant species and restore semiarid wooded steppes. However, their efficiency largely depends on pile persistence and economic cost.