Three hundred years of past and future changes for native fish species in the upper Danube River Basin—Historical flow alterations versus future climate change
The authors show that fish have been particularly sensitive to changes in flow regimes in the past, while higher temperatures will pose the greatest threat in the future. The threat assessment will remain at least as high in the future. However, it could probably be mitigated by reconnecting former floodplains and improving river connectivity.
The shape of density dependence and the relationship between population growth, intraspecific competition and equilibrium population density
The authors focused on extensions of the logistic growth model, and how intrinsic rates of increase and equilibrium population densities are not independent, but instead are functions of the same underlying parameters. They highlight several options for modeling population growth, and provide a mechanistic understanding of how the model parameters of each model relate to one another.
The authors included effects of intraspecific variation to a variance partitioning method that allows quantifying effects of losses and gains of inter- and intraspecific groups to changes in ecosystem functioning. The method will also provide information on how biodiversity loss at different ecological levels changes ecosystem functioning.
The authors used unusual Citizen Science data from several decades to show that the American mink has decimated the native eider duck in the Brokey archipelago by about 60 %. In another Icelandic landscape, the return of the native Arctic fox had no discernible impact on the eider population - presumably due to the common evolutionary history in which the eiders have developed defence strategies.
Patterns and drivers of climatic niche dynamics during biological invasions of island-endemic amphibians, reptiles, and birds
Looking at insular amphibians, reptiles and birds across the world, the authors investigated mismatches between native and non-native climatic niches and how these mismatches can be explained. The results show that climatic mismatches are common for non-native birds and reptiles, but rare for amphibians, and that several factors are significantly related to these mismatches.
Until now, the toxicity assessment of microplastics in the environment relied on the model organism Daphnia magna for evaluating potential hazards to aquatic invertebrates. However, other Daphnia species are primarily found in Northern Hemisphere lakes, most notably Daphnia longispina. The current study reveals that Daphnia longispina can be more sensitive to microplastics than Daphnia magna.
The comprehensive study shows that between 1968 and 2010, biodiversity in river systems in 22 European countries initially recovered due to improved water quality. Since 2010, however, biodiversity has stagnated; many river systems have not fully recovered. The researchers therefore urgently recommend additional measures to further promote the recovery of biodiversity in inland waters.
Phytoplankton Producer Species and Transformation of Released Compounds over Time Define Bacterial Communities following Phytoplankton Dissolved Organic Matter Pulses
Bacterial responses to phytoplankton exudates (DOMp) may be caused by different DOMp compositions. Thereby, the bacterial community leads to a succession of DOMp from highly to less bioavailable, reflected by the temporal presence of specific bacterial phylotypes. The exploitation of species-specific highly bioavailable compounds, results in a more similar remaining DOMp.
Massive expansion of sex-specific SNPs, transposon-related elements, and neocentromere formation shape the young W-chromosome from the mosquitofish Gambusia affinis
The mosquitofish Gambusia affinis, globally introduced to fight mosquitos, is a threat for freshwater ecosystems and a model for sex chromosome evolution. Cyto-/genomics reveals a neocentromere to shield parts of its evolutionary young female sex chromosome (W) that actively differentiates by expansion of transcribed transposons, while major sequence divergence or gene decay are missing.
A synthesis of biological invasion hypotheses associated with the introduction–naturalisation–invasion continuum
Empirical studies show divergent impacts of alien populations on ecosystems which hinders the creation of a unified theory. The authors propose a synthesis that categorizes hypotheses along a timeline of invasion considering population, community and ecosystem levels. For any given case study, this framework provides a guide to choose the appropriate concepts according to the stage of invasion.