A global review on invasive traits of macrophytes and their link to invasion success

Abstract: Aim Biological invasions by exotic macrophytes represent one of the main reasons for biodiversity and ecosystem changes in aquatic ecosystems. The reasons for their ability to succeed in new environments have been of ecological interest in the last years. We made a global review, aiming to describe functional traits related with invasiveness of macrophytes. Methods Our search was performed using keywords regarding invasive macrophytes and functional traits. We related the group traits of invasive species with their probability of species invasion success in new localities (invasiveness). We also performed a nestedness analysis that helped us to see which species possessed the higher number of traits related to invasiveness, as well as which traits were more common among the invasive species. Results Traits most often related to invasiveness were those indicating growth (94.5%) and reproduction (90.1%). Nearly 70.4% of invasive macrophytes traits were related with the probability of invasion success. Invasive species had a higher number of morphological and biotic interaction traits related with invasiveness than native species. Our nestedness analysis indicated a low degree of nestedness, but showed us that Egeria densa, Elodea canadensis and Elodea nutalli were the species with a wider range of environmental tolerances, explaining their invasibility across ecosystems. Conclusions We summarized and complement existing reviews on the functional traits related to invasion success of macrophytes. We believe this review contributed to the identification of the most common set of traits related with invasiveness, helping to speculate on successful invaders in the future

Modularity in host-parasite mixed-networks: interaction configuration shifts based on human perturbation and parasitism form

Parasitism is an association based on host individual traits and environmental factors. The complexity of this type of interaction is often lost when studying species-by-species interaction networks. Here we analyze changes in modularity - a metric describing groups of nodes interacting much more frequently among themselves than they do with nodes of other modules, considering the host individual variation and the different forms of parasitism: ecto- and endo parasitism. For this, we studied mixed networks: bipartite networks comprising host individuals and parasite species as two sets of nodes interacting with each other. We used a fish-parasite mixed-network from a highly perturbed coastal river to understand how an anthropogenic perturbation gradient influences the modular structure of host-parasite networks. In addition, we tested how host individual traits drove module configuration within host-parasite mixed-networks. Our results showed that different forms of parasitism respond differently to the environment: modularity in fish-ectoparasite networks increased with human perturbation, but modularity was not related to human perturbation in fish-endoparasite networks. In addition, mixed-network module were intrinsically related to individual variation, with host intensity of infection being the most important trait, regardless of the parasite’s life form. The effect of total abundance over network structure indicates signs of changes in community equilibrium, with an increase of species with opportunistic behavior. Module composition was also related to host fitness and body size, which were most predictive in more preserved and diverse river sections. Overall, our results indicate that host-parasite networks are sensitive to ecological gradients marked by human perturbations and that individual fitness helps to determine network structure

Nutrient enrichment is related to two facets of beta diversity for stream invertebrates across the united states

Beta diversity, the spatial or temporal variability of species composition, is a key concept in community ecology. However, our ability to predict the relative importance of the main drivers of beta diversity (e. g., environmental heterogeneity, dispersal limitation, and environmental productivity) remains limited. Using a comprehensive data set on stream invertebrate assemblages across the continental United States, we found a hump-shaped relationship between beta diversity and within-ecoregion nutrient concentrations. Within-ecoregion compositional dissimilarity matrices were mainly related to environmental distances in most of the 30 ecoregions analyzed, suggesting a stronger role for species-sorting than for spatial processes. The strength of these relationships varied considerably among ecoregions, but they were unrelated to within-ecoregion environmental heterogeneity or spatial extent. Instead, we detected a negative correlation between the strength of species sorting and nutrient concentrations. We suggest that eutrophication is a major mechanism disassembling invertebrate assemblages in streams at a continental scale

Main predictors of phytoplankton occurrence in lotic ecosystems

Abstract: Aim Our goal was to relate the phytoplankton metacommunity to its possible determinants in a micro watershed: (I) determinants related to landscape-scale filtering, (II) determinants referring to local microhabitat filtering, (III) determinants referring to previous colonization, and (IV) determinants representing three different dispersal routes. Methods Eight sampling stations were selected along the Cascavel River watershed, located in the state of Paraná, Brazil. Samples were collected quarterly for three years. All phytoplankton samples were quantitatively analyzed to determine the density of the metacommunity. In addition, it was characterized the landscape in terms of land use and occupation, and environmental characterization in terms of physical and chemical variables of the water. All data underwent relevant statistical analysis, where variance partitioning was carried out using partial RDA models, with prior selection of predictor variables, to estimate the relative role of each predictor in the community. We also compared three possible dispersal routes: “Asymmetric Eigenvector Map” (AEM), “Overland” and “Watercourse”. Results It was found that the metacommunity was best explained by “asymmetric eigenvector mapping” (AEM), indicating that because it is a small spatial scale the high connectivity between the sampling stations enables species to disperse overland as well. The different filters act together and depend on rainfall variation. Besides fluctuating temporally, the influence of these mechanisms is subject to which dispersal hypothesis is being considered. Conclusions At the watershed scale, we argue that small-scale processes should be considered, since they homogenize the landscape and consequently leave the environmental gradient similar between sampling stations. In addition, the connectivity of colonization patches is essential to understand the behavior of microalgae that have a high dispersal capacity and are not restricted only to the river course

Aquatic ecosystem services: an overview of the Special Issue

The dependency of human wellbeing from ecological systems has been long recognized. At the same time, ecosystems’ integrity and their capacity to sustain human wellbeing have been threatened (Vörösmarty et al., 2010; Steffen et al., 2015; Culhane et al., 2019). One way of raising public awareness about ecosystems’ value and the need for their protection is to recognize and value the services they provide to society (Bull et al., 2016); an approach that is not without criticism (Bekessy et al., 2018)...Fil: Ferreira, Verónica. Universidad de Coimbra; PortugalFil: Bini, Luis Mauricio. Universidade Federal de Goiás; BrasilFil: Gonzalez Sagrario, Maria de Los Angeles. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Marinas y Costeras. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Marinas y Costeras; ArgentinaFil: Kovalenko, Katya E.. University of Minnesota; Estados UnidosFil: Naselli Flores, Luigi. Università degli Studi di Palermo; ItaliaFil: Padial, Andre Andrian. Universidade Federal do Paraná; BrasilFil: Padisák, Judit. University of Pannonia; Hungría. ELKH-PE Limnoecology Research Group; Hungrí