Biology subjects

Langhans, S. D.

Publications and source records attributed to Langhans, S. D..

3 recordsLinked to original sources

bioRxiv2021

300 years of change for native fish species in the upper Danube River Basin - historical flow alterations versus future climate change

River ecosystems belong to the most threatened ecosystems on Earth. Historical anthropogenic alterations have, and future climate change will further affect river ecosystems and the species therein. While many studies assess the potential effects of expected future changes on species, little is known about the severity of these changes compared to historical alterations. Here, we used a unique 300-year time series of hydrological and climate data to assess the vulnerability of 48 native fish species in the upper Danube River Basin. We calculated species-specific vulnerability estimates relative to the reference period (1970-2000) for the periods 1800-1830, 1900-1930, and 2070-2100, including two Representative Concentration Pathways (RCP 4.5 and 8.5) and identified the environmental drivers of vulnerability estimates. Models showed that future changes under RCP 4.5 would result in moderate species vulnerability compared to historical conditions, while under RCP 8.5, the vulnerability for all species increased substantially. In addition, species vulnerability was mainly driven by hydrology in the past and is likely to be driven by temperature in the future. Our results show that future climate change would alter environmental conditions for riverine fish species at a similar magnitude as historical anthropogenic hydrological river alterations have. Shedding light on such long-term historical and possible future anthropogenic alterations provides valuable insights for prioritising conservation actions for riverine fish species.

ecology↗

bioRxiv2020

The untapped potential of conservation journals to promote freshwater biodiversity

Freshwater ecosystems are amongst the most diverse ecosystems on the planet. They are subject to intense and increasing threats and have a higher proportion of threatened and extinct species than terrestrial or marine realms. Concurrently, freshwater ecosystems are largely underrepresented in both conservation research and actions arguably as a consequence of less popularity and promotion. To test this assumption, we used cover images as a proxy of exposure and promotion opportunities provided by conservation journals. We collected information on cover images of 18 conservation journals from 1997 to 2016 and data on citations and Altmetric scores of papers published in them. We found that freshwater ecosystems (10.4%) were featured less often than marine (15.2%) or terrestrial (74.4%) ecosystems on covers of these journals. All 15 most featured species are from terrestrial or marine ecosystems, with 14 of them being large vertebrates such as elephants, big cats, rhinos, polar bears, and marine turtles. None of the 95 species featured more than once on the covers of conservation journals spend their whole life history in fresh waters, i.e. they are at least partly associated with terrestrial or marine ecosystems. Our results indicated that cover-featured studies received more attention from academia and the general public, i.e. showed higher citations and Altmetric scores, than non-featured ones within the same issue. By featuring freshwater species and habitats on covers, therewith providing more exposure opportunities, conservation journals hold the potential to promote biodiversity conservation in fresh waters. Scientists can help that endeavour by submitting freshwater-related photos together with their manuscripts for review, therewith providing more options for editors to portray freshwater species and habitats and to ultimately raise awareness and appreciation of freshwater life.

scientific communication and education↗

bioRxiv2018

Evaluation of habitat protection under the European Natura 2000 conservation network - the example for Germany

The worlds largest network of protected areas - Natura 2000 (N2000) - has been implemented to protect Europes biodiversity. N2000 is built upon two cornerstones, the Birds Directive, which lists 230 bird species and the Habitats Directive, which lists next to a variety of species 230 habitat types, to be protected. There is evidence of the positive impact of the Directives on the EUs biodiversity, although the overall improvement reported for species in favourable condition in the last assessment was low. However, most of the assessments are species focused, while habitats have received very little attention. Here we developed a generic workflow, which we exemplified for Germany, to assess the status of habitat coverage within the N2000 network, combining information from publicly available data sources. Applying the workflow allows identifying gaps in habitat protection, followed by the prioritization of potential areas of high protection value, using the conservation planning software Marxan. We found that, in Germany, N2000 covers all target habitats. However common habitats were proportionally underrepresented relative to rare ones, which contrasts with comparable studies for species. Moreover, the German case study suggests that especially highly protected areas (i.e. covered by more than 90% with N2000 sites) build an excellent basis towards a cost-effective and efficient conservation network. Our workflow provides a generic approach to deal with the popular problem of missing habitat distribution data outside of N2000 sites, information which is however crucial for managers to plan conservation action appropriately across Europe. To avoid a biased representation of habitat types within N2000, our results underpin the importance of defining qualitative and quantitative conservation targets which will allow assessing the trajectory of habitat protection in Europe as well as adjusting the network accordingly - a future necessity in the light of climate change.

ecology↗