No abstract

Summary Biological invasions represent one of the main threats to biodiversity and a recognized economic burden worldwide; the issue has been included in the conservation agenda such as the Convention on Biological Diversity (CBD). Brazil is a signatory country of the CBD; however, the number of alien species records in its territory is continuously rising. To evaluate the invasive alien species (IAS) policy in Brazil, we reviewed the legislation delineating historical trends to identify potential gaps and avenues for improvement. We consulted several websites using keywords related to invasions in order to track legal instruments such as laws, decrees and regulations. We classified the documents regarding their main aims with regard to IAS, taxon and environment of interest. We found 85 legal instruments in force related to IAS published in the federal sphere up to October 2021, with decrees being the most common type. Most documents were classified as ‘control’ and ‘prevention’ and were related to all taxa and environments. Two species (wild boar Sus scrofa and golden mussel Limnoperna fortunei) have more specific legislation, probably due to their conspicuous economic impacts. We discuss policy gaps and their implications for the efficient management and prevention of new IAS introductions to the country.

Biological invasions are one of the major threats to the integrity of aquatic ecosystems worldwide. We examined the influence of reservoirs, availability of food resources, abiotic resistance, and biotic resistance on the distribution of Daphnia lumholtzi, a non‐native cladoceran that is spreading through habitats in the upper Paraná River basin, Brazil. We sampled 48 sites distributed in four habitat types: reservoirs, lakes, tributaries, and the main river. D. lumholtzi densities were higher in reservoirs than in other habitat types (lentic and lotic). We found a significant correlation between a higher density of D. lumholtzi and the distance from reservoirs to the other sampling points. Additionally, a relationship between D. lumholtzi and types of environments was noted. It is known that cladocerans, including D. lumholtzi, have a reduced swimming ability, which makes it difficult for them to overcome currents and consequently establish or maintain large populations in lotic environments. Further research is needed to identify other factors responsible for the species' occurrence in this system and to determine the possible effects this species may have on the native community.

Studies of metacommunities are of great importance for ecological knowledge because they assess how the processes related to the species' niche and the dispersion processes structure the communities. In this context, the objective of the present study was to investigate the main assembly mechanisms responsible for the structuring of the zooplankton community in a complex of neotropical palm swamps ("veredas"), consisting of sets of small common ponds in the Brazilian savannah, similar to swamps. Zooplankton were sampled in the pelagic region of 15 veredas in April 2018. The zooplankton total community showed a distribution related to spatial and environmental factors. For Rotifera the relative importance of environmental factors was greater, while Cladocera and Copepoda were more structured by space. The community was still structured according to the Gleasonian model of distribution, where Rotifera presented a Gleasonian structure, Cladocera quasi-Gleasonian, and Copepoda quasi-nested random. The influence of environmental and spatial factors and the resulting structure of the zooplankton metacommunity seem to be directly related to the dispersal capacity in each group.Differences in relative importance of the factors that shaped the community highlight the idiosyncratic characteristics of zooplankton species. Thus, we emphasize the importance of using the two approaches of metacommunity studies to help to elucidate the processes that govern the structuring of metacommunities.

The introduction of non-native species is one of the most important causes of biodiversity loss. Non-native organisms are not recognized by native communities, leading to differential predation rates and differential impacts on a variety of ecological interactions. In this context, the present study was intended to carry out a review of the literature on the impacts of non-native zooplankters on the zooplankton and the dynamics of aquatic ecosystems--literature reviews are a valuable tool that can highlight gaps and find possible biases in our understanding of biological invasions. We carried out a review of the current literature (20 years) looking for any alteration in the natural dynamics of the environment at all ecological levels. A total of 181 studies that addressed some type of non-native zooplankton effect were included in the review. Most studies focused on a just few non-native species and evidenced demographic changes at the population level. A geographic bias in favor of North America was also found. The various gaps in the literature on non-native zooplankton are derived from the same problem, an excessive number of investigations of the same taxa in the same places. Consequently, the recorded impacts are similar since they come from the same groups, and neglect less studied, but not necessarily less impactful, species. A greater focus on studies of lesser-known species could generate more comprehensive knowledge about the effects of non-native zooplankton and contribute to the distribution of conservation efforts beyond the better-known species.