Search results for "Fish"

Male-biased sexual size dimorphism in the nest building corkwing wrasse (Symphodus melops): implications for a size regulated fishery

2016

Technical Solutions to Mitigate Shifting Fish Fauna Zones Impacted by Long Term Habitat Degradation in the Bistra Mărui River – Study Case

2018

Abstract The Bistra Mărului River fish fauna has been severely impacted by man-made activities, especially through longitudinal fragmentation, over the past 40 years. Fish fauna monitoring revealed structural changes and technical methods have been proposed, in order to restore the natural connectivity and the conservation of fish species. Benefits should accrue for key species: Salmo trutta fario, Cottus gobio, Thymallus thymallus, Eudontomyzon danfordi, Eudontomyzon vladykovi, Gobio uranoscopus, Barbus meridionalis, and Condrostoma nasus.

Native and invasive hosts play different roles in host–parasite networks

2020

Parasites are often key players in biological invasions since they can mediate the impact of host invasions or can themselves become invasive species. However, the nature and extent of parasite‐mediated invasions are often difficult to delineate. Here, we used individual‐based, weighted bipartite networks to study the roles (degrees of interactions of individuals in a modular network according to their within‐ and among‐module connections) played by native and invasive host individuals to their parasite communities. We studied two phylogenetically and ecologically close fish species, Mugil cephalus s.l. and Planiliza haematocheilus (Teleostei: Mugilidae). Planiliza haematocheilus is native …

Potential of contemporary evolution to erode fishery benefits from marine reserves

2016

Marine reserves are valued for their ecological role: protecting fish populations from overharvesting while, at the same time, potentially maintaining fisheries yields via recruitment effects (net export of pelagic eggs and larvae) and spillover (net export of post-settled juveniles and mature fish) across reserve borders. Focussing on the spillover effect, we argue that when fitness of the protected individuals depends on the relative size of their home ranges compared to the reserve size, and home range size is a property of the individuals, rapid local adaptation might occur in favour of individuals with smaller home ranges. Individuals that avoid fishing mortality by spending most of th…

Combining environmental DNA and species distribution modeling to evaluate reintroduction success of a freshwater fish

2019

Active species reintroduction is an important conservation tool when aiming for the restoration of biological communities and ecosystems. The effective monitoring of reintroduction success is a crucial factor in this process. Here, we used a combination of environmental DNA (eDNA) techniques and species distribution models (SDMs) to evaluate the success of recent reintroductions of the freshwater fish Alburnoides bipunctatus in central Germany. We built SDMs without and with eDNA presence data to locate further suitable reintroduction sites and potentially overlooked populations of the species. We successfully detected eDNA of A. bipunctatus at all reintroduction sites, as well as several a…

Testing the usefulness of habitat corridors in mitigating the negative effects of fragmentation: the soil faunal community as a model system

2004

Abstract The corridor hypothesis predicts that habitat corridors should attenuate the negative effects of fragmentation on populations or communities by enhancing the dispersal of organisms between the habitat fragments (the ‘rescue effect’). In the present 12-month mesocosm experiment, this hypothesis was tested using the soil micro- and mesofaunal community in humus patches—either connected or unconnected with humus corridors to each other—as a model system. Of particular interest was to explore whether faunal groups with differing life strategies (e.g. in trophic position and dispersal capacity) would differ in their responses to the corridors. The results showed that enchytraeid worms w…

Colonisation of newly established habitats by soil decomposer organisms: the effect of habitat corridors in relation to colonisation distance and hab…

2005

Abstract The aim of the present 2.5-year-long field experiment was to explore the ability of various members of the detrital food web to colonise newly established habitat patches in field conditions, either in the presence or absence of habitat corridors. Patch size and distance to the “mainland” (colonisation source) were manipulated to explore the scale dependency of the corridor effects. Sterilised humus patches, embedded in mineral soil regarded as uninhabitable (or non-preferred) matrix for the soil organisms, functioned as newly established habitats. Intact forest soil served as the source of colonisers. Three kinds of patches were established: large ones situated at relatively long …

Differential recovery of habitat use by birds after wind farm installation: A multi-year comparison

2017

Abstract Onshore wind farms remain one of the most widely used technologies for the production of renewable energy. These are known to affect birds through disturbance or collision. Most research focus on the impact of wind farms on raptors or other large bird species, especially those of conservation concern. However, limited information exists on the effect of wind farms on small birds. Recovery of large versus small bird populations impacted by wind farms is also largely unstudied. A reason for this is the lack of long-term datasets based on standardized, systematic assessments. We monitored birds in the vicinity of a wind farm in an upland habitat in southern Spain (Malaga province), im…

Small-scale life history variability suggests potential for spatial mismatches in Atlantic cod management units

2015

Do enchytraeid worms and habitat corridors facilitate the colonisation of habitat patches by soil microbes?

2004

Due to their high abundance and ubiquitous existence, microbes are considered to be efficient colonisers of newly established habitats. To shed light on the dispersal mechanisms of soil microbes, a controlled microcosm experiment was established. In these microcosms, the dispersal of microbes from a source humus patch to originally sterile humus patches (embedded in a mineral soil matrix) was followed for 16 months, applying 16S and 18S ribosomal DNA-based PCR-DGGE molecular methods. Specifically, the role of enchytraeid worms and habitat (humus) corridors as possible facilitators of microbe dispersal was studied. The results showed that enchytraeid worms function efficiently as vectors for…