Effect of recreational‐fisheries management on fish biodiversity in gravel pit lakes, with contrasts to unmanaged lakes

Gravel pit lakes are novel ecosystems that can be colonized by fish through natural or anthropogenic pathways. In central Europe, many of them are managed by recreational anglers and thus experience regular fish stocking. However, also unmanaged gravel pits may be affected by stocking, either through illegal fish introductions or, occasionally, by immigration from connected water bodies. We sampled 23 small (< 20 ha) gravel pit lakes (16 managed and 7 unmanaged) in north‐western Germany using littoral electrofishing and multimesh gillnets. Our objective was to compare the fish biodiversity in gravel pit lakes in the presence or absence of recreational fisheries. Given the size of the sampled lakes, we expected species poor communities and elevated fish diversity in the managed systems due to regular stocking of game fish species. Our study lakes were primarily mesotrophic and did not differ in key abiotic and biotic environmental characteristics. Lakes of both management types hosted similar fish abundances and biomasses, but were substantially different in terms of fish community structure and species richness. Fish were present in all lakes, with a minimum of three species. Higher α‐diversity and lower β‐diversity was discovered in managed gravel pit lakes compared to unmanaged lakes. Consequently, recreational‐fisheries management fostered homogenization of fish communities, by stocking a similar set of fish species desired by anglers such as piscivorous fish and large bodied cyprinids. However, unmanaged gravel pit lakes were also affected by human‐mediated colonization, presumably by illegal fish releases. Hardly any non‐native species were detected, suggesting that recreational‐fisheries management did not foster the spread of exotic species in our study region

Effect of recreational‐fisheries management on fish biodiversity in gravel pit lakes, with contrasts to unmanaged lakes

Gravel pit lakes are novel ecosystems that can be colonized by fish through natural or anthropogenic pathways. In central Europe, many of them are managed by recreational anglers and thus experience regular fish stocking. However, also unmanaged gravel pits may be affected by stocking, either through illegal fish introductions or, occasionally, by immigration from connected water bodies. We sampled 23 small (< 20 ha) gravel pit lakes (16 managed and 7 unmanaged) in north‐western Germany using littoral electrofishing and multimesh gillnets. Our objective was to compare the fish biodiversity in gravel pit lakes in the presence or absence of recreational fisheries. Given the size of the sampled lakes, we expected species poor communities and elevated fish diversity in the managed systems due to regular stocking of game fish species. Our study lakes were primarily mesotrophic and did not differ in key abiotic and biotic environmental characteristics. Lakes of both management types hosted similar fish abundances and biomasses, but were substantially different in terms of fish community structure and species richness. Fish were present in all lakes, with a minimum of three species. Higher α‐diversity and lower β‐diversity was discovered in managed gravel pit lakes compared to unmanaged lakes. Consequently, recreational‐fisheries management fostered homogenization of fish communities, by stocking a similar set of fish species desired by anglers such as piscivorous fish and large bodied cyprinids. However, unmanaged gravel pit lakes were also affected by human‐mediated colonization, presumably by illegal fish releases. Hardly any non‐native species were detected, suggesting that recreational‐fisheries management did not foster the spread of exotic species in our study region

Die Energiewende regional gestalten : auf dem Weg zu einer Energiewende-Roadmap im Ruhrgebiet

Diese Broschüre ist ein Produkt des Rahmenprogramms zur Umsetzung der Energiewende in den Kommunen des Ruhrgebiets: Die Auf­gabe des Projektes bestand darin auszuloten, in welcher Weise Kommunen ihre Handlungskapazitäten zur Umsetzung der Energiewende in der Region bewahren beziehungsweise perspektivisch erweitern können. Das Rahmenprogramm steuerte in seiner dreijährigen Projektlaufzeit (2013-2016) einen Beitrag zur Analyse der Handlungsfähigkeit von Kommunen im Ruhrgebiet zur Umsetzung der Energiewende bei und systematisierte bisherige Handlungsansätze in der Region. Es setzte an bestehenden Rahmenbedingungen an und versuchte, in Zusammenarbeit mit regionalen Akteurinnen und Akteuren künftige Handlungsansätze für eine langfristig angelegte Umsetzung der Energiewende in der Region zu identifizieren. Das vorliegende Dokument führt Ergebnisse des Pro­jektes zusammen und formuliert strategische Hinweise für die weitere Umsetzung der Energiewende im Ruhrgebiet

Terrestrial mosses as biomonitors of atmospheric POPs pollution: a review

Worldwide there is concern about the continuing release of persistent organic pollutants (POPs) into the environment. In this study we review the application of mosses as biomonitors of atmospheric deposition of POPs. Examples in the literature show that mosses are suitable organisms to monitor spatial patterns and temporal trends of atmospheric concentrations or deposition of POPs. These examples include polycyclic aromatic hydrocarbons (PAHs), polychlorobiphenyls (PCBs), dioxins and furans (PCDD/ Fs), and polybrominated diphenyl ethers (PBDEs). The majority of studies report on PAHs concentrations in mosses and relative few studies have been conducted on other POPs. So far, many studies have focused on spatial patterns around pollution sources or the concentration in mosses in remote areas such as the polar regions, as an indication of long-range transport of POPs. Very few studies have determined temporal trends or have directly related the concentrations in mosses with measured atmospheric concentrations and/or deposition fluxes