While biodiversity loss is undeniably a global phenomenon, an increase in taxonomic richness has recently been reported from some ecosystems and spatial scales. A striking increase in abundance and/or species richness has been documented from temperate rivers over the last 25 years, with many of the expanding species (i.e. winners) being native species. However, the lack of repeatedly collected local environmental data prevents the exploration of their niche dynamics and also makes it difficult to distinguish between possible causes. We fill this gap by using species occurrence data from 65 pristine Czech rivers sampled in 1997-2000 and 2015. The same methods were used for sampling macroinvertebrates and measuring environmental parameters in both periods. We selected 43 winners, defined as taxonomically validated and originally non-rare native macroinvertebrate species whose occupancy increased by at least six sites between the time periods. We searched for consistent patterns of niche dynamics (i.e. stability, expansion and restriction) among species that might contribute most to the overall increase in species richness. Using several biological traits, we also compared the winners with the other 253 taxa collected to look for differences. Analysis of the occurrence data showed that niche stability was by far the predominant pattern of the niche dynamics. This clearly indicates that the winners fill their original niches, with a limited contribution of niche shift or expansion, depending on the species. As no significant differences in either temperature preferences or the other biological traits were found between the winners and the other taxa, there is no unique set of functional traits that explain the success of the winners. The observed mechanism of filling the original niche space by the spreading native species not only explains the increase in local species richness, but also contributes to support the hypothesis of a climate-driven increase in ecosystem energy flow from a new perspective. The increased metabolism of the system may relax interspecific competition allowing it to carry more individuals and species, even without the need for an increase in nutrients and ecosystem recovery.

• Klíčová slova
• aquatic invertebrates, increasing temperature, long‐term changes, niche filling, niche shift, streams, winners,
• MeSH
• bezobratlí * fyziologie   MeSH
• biodiverzita * MeSH
• ekosystém * MeSH
• populační dynamika MeSH
• řeky * MeSH
• zavlečené druhy * MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Česká republika MeSH

Owing to a long history of anthropogenic pressures, freshwater ecosystems are among the most vulnerable to biodiversity loss1. Mitigation measures, including wastewater treatment and hydromorphological restoration, have aimed to improve environmental quality and foster the recovery of freshwater biodiversity2. Here, using 1,816 time series of freshwater invertebrate communities collected across 22 European countries between 1968 and 2020, we quantified temporal trends in taxonomic and functional diversity and their responses to environmental pressures and gradients. We observed overall increases in taxon richness (0.73% per year), functional richness (2.4% per year) and abundance (1.17% per year). However, these increases primarily occurred before the 2010s, and have since plateaued. Freshwater communities downstream of dams, urban areas and cropland were less likely to experience recovery. Communities at sites with faster rates of warming had fewer gains in taxon richness, functional richness and abundance. Although biodiversity gains in the 1990s and 2000s probably reflect the effectiveness of water-quality improvements and restoration projects, the decelerating trajectory in the 2010s suggests that the current measures offer diminishing returns. Given new and persistent pressures on freshwater ecosystems, including emerging pollutants, climate change and the spread of invasive species, we call for additional mitigation to revive the recovery of freshwater biodiversity.

• MeSH
• bezobratlí * klasifikace   fyziologie   MeSH
• biodiverzita * MeSH
• časové faktory MeSH
• globální oteplování MeSH
• hydrobiologie MeSH
• látky znečišťující vodu analýza   MeSH
• lidské činnosti MeSH
• monitorování životního prostředí * MeSH
• ochrana vodních zdrojů * statistika a číselné údaje   trendy   MeSH
• pěstování plodin MeSH
• sladká voda * MeSH
• urbanizace MeSH
• zavlečené druhy trendy   MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Geografické názvy
• Evropa MeSH
• Názvy látek
• látky znečišťující vodu MeSH

While there has been increasing interest in how taxonomic diversity is changing over time, less is known about how long-term taxonomic changes may affect ecosystem functioning and resilience. Exploring long-term patterns of functional diversity can provide key insights into the capacity of a community to carry out ecological processes and the redundancy of species' roles. We focus on a protected freshwater system located in a national park in southeast Germany. We use a high-resolution benthic macroinvertebrate dataset spanning 32 years (1983-2014) and test whether changes in functional diversity are reflected in taxonomic diversity using a multidimensional trait-based approach and regression analyses. Specifically, we asked: (i) How has functional diversity changed over time? (ii) How functionally distinct are the community's taxa? (iii) Are changes in functional diversity concurrent with taxonomic diversity? And (iv) what is the extent of community functional redundancy? Resultant from acidification mitigation, macroinvertebrate taxonomic diversity increased over the study period. Recovery of functional diversity was less pronounced, lagging behind responses of taxonomic diversity. Over multidecadal timescales, the macroinvertebrate community has become more homogenous with a high degree of functional redundancy, despite being isolated from direct anthropogenic activity. While taxonomic diversity increased over time, functional diversity has yet to catch up. These results demonstrate that anthropogenic pressures can remain a threat to biotic communities even in protected areas. The differences in taxonomic and functional recovery processes highlight the need to incorporate functional traits in assessments of biodiversity responses to global change.

• Klíčová slova
• freshwater, functional diversity, functional redundancy, long term, long‐term ecosystem research, macroinvertebrate, protected area,
• Publikační typ
• časopisecké články MeSH

Dispersal is an essential process in population and community dynamics, but is difficult to measure in the field. In freshwater ecosystems, information on biological traits related to organisms' morphology, life history and behaviour provides useful dispersal proxies, but information remains scattered or unpublished for many taxa. We compiled information on multiple dispersal-related biological traits of European aquatic macroinvertebrates in a unique resource, the DISPERSE database. DISPERSE includes nine dispersal-related traits subdivided into 39 trait categories for 480 taxa, including Annelida, Mollusca, Platyhelminthes, and Arthropoda such as Crustacea and Insecta, generally at the genus level. Information within DISPERSE can be used to address fundamental research questions in metapopulation ecology, metacommunity ecology, macroecology and evolutionary ecology. Information on dispersal proxies can be applied to improve predictions of ecological responses to global change, and to inform improvements to biomonitoring, conservation and management strategies. The diverse sources used in DISPERSE complement existing trait databases by providing new information on dispersal traits, most of which would not otherwise be accessible to the scientific community.

• MeSH
• bezobratlí * MeSH
• ekologie MeSH
• monitorování životního prostředí MeSH
• rozšíření zvířat * MeSH
• vodní organismy * MeSH
• zachování přírodních zdrojů MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• dataset MeSH
• práce podpořená grantem MeSH
• Geografické názvy
• Evropa MeSH