Benthic invertebrate neozoa in Austrian rivers

Neozoa werden als gebietsfremde Arten definiert, welche nach 1492 direkt oder indirekt durch den Menschen eingeführt wurden und selbstreproduzierende Populationen zu bilden im Stande sind (Essl & Rabitsch 2002). Biologische Invasionen sind schon seit dem Zeitalter des Kolonialismus ein bekanntes Phänomen, gegenwärtig hat das Problem in einer Zeit der Globalisierung von Wirtschaft und Tourismus und einer globalen Klimaveränderung jedoch eine neue Dimension und Geschwindigkeit erreicht. In Österreich gibt es grundsätzlich eine gute Datenbasis über das Auftreten von benthischen Einwanderern. Bereits in der älteren Literatur findet man dazu einige Hinweise, z.B.: Strouhal (1939), Vornatscher (1965) und Liepolt (1965–67). Größere Aufmerksamkeit wurde dem Phänomen invasiver Arten seit der massiven Ausbreitung der Dreikantmuschel Dreissena polymorpha geschenkt, als sich diese in den 1970er Jahren in vielen Flüssen und Seen in einem sehr kurzen Zeitraum ausbreitete. Verstärkte Beachtung wurde den Neozoa in der Limnologie aber erst im letzten Jahrzehnt zuteil, als die Fundnachweise immer häufiger wurden und sowohl ökonomische als auchbemerkenswerte ökologische Auswirkungen durch invasive Arten vermutet oder nachgewiesen wurden. Beispielsweise belegte Gruber (2006), dass der autochthone Steinkrebs (Austropotamobius torrentium) bereits bis in die Quellregion hinein durch den amerikanischen Signalkrebs (Pacifastacus leniusculus) verdrängt wird. In Österreich entstand als Folge des erhöhten Problembewusstseins in den letzten Jahren eine Reihe von umfassenden Publikationen zum Thema Neobiota: „Invaders“ (Aescht & al. 1995), „Neobiota in Österreich“ (Essl & Rabitsch 2002) und „Aliens“ (Wallner 2005). Während die überwiegende Zahl der Publikationen zum Thema Neozoa von taxonomischen Fachspezialisten stammt und deshalb zumeist auf eine oder einige ausgewählte Tiergruppen beschränkt bleibt, basiert vorliegender Beitrag auf Monitoringdaten und gewässerökologischen Untersuchungen, in welchen immer die gesamte Artengesellschaft der benthischen Evertebraten erhoben wurde.Based on 9,544 data sets from 1,060 Austrian rivers and streams the paper gives a quantitative and qualitative overview of the occurrence and distribution of benthic invertebrate neozoa in Austrian running waters. Excluding those species that have been recorded only as single findings or which inhabit greenhouses with no connection to natural water bodies, a total number of 46 benthic invertebrate species can be classified as neozoa for Austria. Referred to the known number of about 3,200 benthic macro-invertebrate species the neozoa fauna comprises only a small amount of 1.8 %. On the other hand these neozoa colonise 16.1% of the investigated water bodies. Most investigation sites are inhabited by only one neozoa species. The maximum number of neozoa species found at one investigation site was not higher than 13. However, at some river sites the abundance of neobiota specimens can clearly dominate the benthic community. E. g. a maximum number of about 500,000 Corophium curvispinum individuals per m² (99% of the total abundance) with a biomass up to 0.6 kg fresh weight per m² has been observed in the River Morava (Lower Austria), a neozoa biomass of 7 kg/m2 (Corbicula fluminea) was documented in a muddy Danube harbour at Linz, Upper Austria. In contrast to the indigenous fauna, which is mainly composed of insects (85%) the neozoa fauna is dominated by Crustacea (53%) and Mollusca (24%). 47% of the neozoa species originate from European regions, mainly the ponto-caspian area. Other important donor areas are North America and South East Asia. With respect to aquatic neozoa in Austria, the River Danube can be clearly identified as the main immigration channel of the ponto-caspian (most of the Mollusca and Crustacea neobiota species) as well as the mediterranean fauna (Atyaephyra desmaresti) and other species that spread via Western Europe, respectively. Although most of the benthic invertebrate neozoa have never left the main Danube channel, a steady immigration from Danube tributaries by some species has been observed in the last years

Incongruent latitudinal patterns of taxonomic, phylogenetic and functional diversity reveal different drivers of caddisfly community assembly across spatial scales

Aim: Community assembly processes are difficult to observe in nature but can be inferred from species diversity patterns. However, taxonomic patterns may be consistent with multiple explanations, such as habitat filtering or biogeographical processes, which can also act differently across spatial scales. Here, we assessed multiple facets of diversity to determine the relative contributions of local versus regional processes and historical versus contemporary factors in establishing macroecological patterns. Location: From the Mediterranean peninsulas to northern Scandinavia. Time period: Species occurrence data gathered since c. 1980. Major organism group studied: Trichoptera (Insecta). Methods: Based on an extensive functional space and a phylogenetic tree including 197 and 509 species, respectively, and the composition of 180 communities, we assessed the distribution of taxonomic, functional and phylogenetic diversity within 18 ecoregions (local α- and β-diversity) and among those ecoregions (regional γ- and β-diversity). Results: Local estimates of taxonomic, functional and phylogenetic α- and β-diversity were similar across Europe, which reveals that all streams have similar carrying capacity even though the local abiotic factors involved are likely different among ecoregions. In contrast, regional taxonomic and phylogenetic diversities decreased as latitude increased, whereas functional richness and functional dispersion displayed unimodal relationships. The position of species on the functional space was not conserved, while northern species pools were found to be phylogenetically clustered and southern ones overdispersed. The nestedness component mainly contributed to the taxonomic and phylogenetic β-diversity among northern communities, whereas in southern latitudes the turnover was dominant. Main conclusions: Decoupled latitudinal patterns of taxonomic, phylogenetic and functional diversity reveal the importance of regional environmental filtering over local factors in limiting species range and shaping the regional species pool. The biogeographical signature is still present; the northern recolonizations following the Pleistocene glaciations originated exclusively from central regions, instead of Mediterranean refugia, as was previously accepted

A trait-based approach to assess the vulnerability of European aquatic insects to climate change

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The Freshwater Information Platform: a global online network providing data, tools and resources for science and policy support

Freshwaters are among the most complex, dynamic, and diverse ecosystems globally. Despite their small share of the earth’s surface (less than 1%) they are home to over 10% of all known animal species. Biodiversity decrease in general and freshwater biodiversity decline in particular have recently received increasing attention, and various policy instruments are now targeting the conservation, protection and enhancement of biodiversity and associated ecosystem services. Surveillance programs as well as a variety of research projects have been producing a tremendous amount of freshwater-related information. Though there have been various attempts to build infrastructures for online collection of such data, tools and reports, they often provide only limited access to resources that can readily be extracted for conducting large scale analyses. Here, we present the Freshwater Information Platform, an open system of relevant freshwater biodiversity-related information. We provide a comprehensive overview of the platform’s core components, highlight their values, present options for their use, and discuss future developments. This is complemented by information on the platform’s current management structure, options for contributing data and research results and an outlook for the future

The Freshwater Information Platform : a global online network providing data, tools and resources for science and policy support

Freshwaters are among the most complex, dynamic, and diverse ecosystems globally. Despite their small share of the earth's surface (less than 1%) they are home to over 10% of all known animal species. Biodiversity decrease in general and freshwater biodiversity decline in particular have recently received increasing attention, and various policy instruments are now targeting the conservation, protection and enhancement of biodiversity and associated ecosystem services. Surveillance programs as well as a variety of research projects have been producing a tremendous amount of freshwater-related information. Though there have been various attempts to build infrastructures for online collection of such data, tools and reports, they often provide only limited access to resources that can readily be extracted for conducting large scale analyses. Here, we present the Freshwater Information Platform, an open system of relevant freshwater biodiversity-related information. We provide a comprehensive overview of the platform's core components, highlight their values, present options for their use, and discuss future developments. This is complemented by information on the platform's current management structure, options for contributing data and research results and an outlook for the future

Safeguarding freshwater life beyond 2020: Recommendations for the new global biodiversity framework from the European experience

Plans are currently being drafted for the next decade of action on biodiversity-both the post-2020 Global Biodiversity Framework of the Convention on Biological Diversity (CBD) and Biodiversity Strategy of the European Union (EU). Freshwater biodiversity is disproportionately threatened and underprioritized relative to the marine and terrestrial biota, despite supporting a richness of species and ecosystems with their own intrinsic value and providing multiple essential ecosystem services. Future policies and strategies must have a greater focus on the unique ecology of freshwater life and its multiple threats, and now is a critical time to reflect on how this may be achieved. We identify priority topics including environmental flows, water quality, invasive species, integrated water resources management, strategic conservation planning, and emerging technologies for freshwater ecosystem monitoring. We synthesize these topics with decades of first-hand experience and recent literature into 14 special recommendations for global freshwater biodiversity conservation based on the successes and setbacks of European policy, management, and research. Applying and following these recommendations will inform and enhance the ability of global and European post-2020 biodiversity agreements to halt and reverse the rapid global decline of freshwater biodiversity

Integration and dissemination of aquatic biodiversity and ecosystem services data for case studies focusing on ecosystem-based management

Aquatic ecosystems –from marine and coastal to freshwater– are rich in biodiversity and home to a diverse array of species and habitats, providing numerous economic and societal benefits to the European population. Many of these valuable ecosystems are at risk of being irreversibly damaged by human activities and pressures, including pollution, contamination, hydromorphological alterations, invasive species, overfishing and climate change. These pressures threaten the sustainability of these ecosystems, their provision of ecosystem services and ultimately human well-being. AQUACROSS (Knowledge, Assessment, and Management for AQUAtic Biodiversity and Ecosystem Services aCROSS EU policies – http://aquacross.eu) seeks to advance the application of ecosystem-based management for aquatic ecosystems in an effort to support the timely achievement of the EU 2020 Biodiversity Strategy and other international conservation targets. In this regard, AQUACROSS aims to develop and test an assessment framework through a series of cases studies which considers the full array of interactions within aquatic ecosystems, including human activities. Following the Horizon 2020 Open Research Data Pilot, AQUACROSS addresses the challenge of bringing together newly generated as well as existing data used in the framework of the case studies, while at the same time supporting the project partners in terms of data integration and harmonisation. Through a lightweight CKAN-based information platform, we aim on one hand to support project partners in terms of discovery and data access (in interoperable formats), while on the other hand we offer operational support to open up raw and processed data for use in other contexts and disseminating these data and results. The latter is facilitated by the capabilities of the CKAN software which includes on-the-fly analysis and visualisation tools and enables easy data access through external software and tools such as R, QGis and Phyton. During this presentation we will report on the main lessons learned during this data integration exercise and focus on selected case study examples

The recovery of European freshwater biodiversity has come to a halt

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.publishedVersio

A global agenda for advancing freshwater biodiversity research

Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation

A global agenda for advancing freshwater biodiversity research

Global freshwater biodiversity is declining dramatically, and meeting the challenges of this crisis requires bold goals and the mobilisation of substantial resources. While the reasons are varied, investments in both research and conservation of freshwater biodiversity lag far behind those in the terrestrial and marine realms. Inspired by a global consultation, we identify 15 pressing priority needs, grouped into five research areas, in an effort to support informed stewardship of freshwater biodiversity. The proposed agenda aims to advance freshwater biodiversity research globally as a critical step in improving coordinated actions towards its sustainable management and conservation.Peer reviewe