Worldwide, incidental bycatch in fisheries is a conservation threat to many seabird species. Although knowledge on bycatch of seabirds has increased in the last decade, most stems from longline fisheries and the impacts of coastal gillnet fisheries are poorly understood. Gillnet fishing for North Atlantic lumpsucker (Cyclopterus lumpus) is one such fishery. We collated and synthesized the available information on seabird bycatch in lumpsucker gillnet fisheries across the entire geographical range to estimate and infer the magnitude of their impact on the affected seabird populations. Most birds killed were diving ducks, cormorants and auks, and each year locally high numbers of seabirds were taken as bycatch. We found large differences in bycatch rates among countries. The estimated mean bycatch in Iceland was 2.43 birds/trip, while the estimates in Norway was 0.44 and 0.39 birds/trip, respectively. The large disparities between estimates might reflect large spatial differences in bycatch rates, but could partly also arise due to distinctions in data recorded by onboard inspectors (Iceland), self-administered registration (Norway) and direct observations by cameras (Denmark). We show that lumpsucker gillnet fisheries might pose a significant risk to some populations of diving seabirds. However, a distinct data deficiency on seabird bycatch in terms of spatio-temporal coverage and the age and origins of the birds killed, limited our abilities to fully assess the extent and population consequences of the bycatch. Our results highlight the need for a joint effort among countries to standardize monitoring methods to better document the impact of these fisheries on seabirds.
The Arctic fox (Vulpes lagopus) population in Fennoscandia experienced a drastic bottleneck in the late 19th century as a result of high hunting pressure. In the 1990s, despite nearly 70 years of protection, the population showed no signs of recovery. In order to mitigate the population decline and facilitate re-establishment, conservation actions including supplementary feeding and red fox culling were implemented in 1998, followed by the reintroduction of foxes from a captive breeding programme, starting in 2006. A positive demographic impact of these actions is evident from a doubling of the population size over the past decade. We used genetic data collected in eight subpopulations between 2008 and 2015 to address whether the recent demographic recovery has been complemented by changes in genetic variation and connectivity between subpopulations. Our results show that genetic variation within subpopulations has increased considerably during the last decade, while genetic differentiation among subpopulations has decreased. A marked shift in metapopulation dynamics is evident during the study period, suggesting substantially increased migration across the metapopulation. This shift followed the recolonization of an extinct subpopulation through the release of foxes from the captive breeding programme and was synchronized in time with the implementation of supplementary feeding and red fox culling in stepping stone patches between core subpopulations in mid-Scandinavia. Indeed, the increase in genetic variation and connectivity in the Scandinavian arctic fox population suggests that metapopulation dynamics have been restored, which may indicate an increase in the long-term viability of the population.
This study investigates the influence of fragment size on tree species composition, speciesrichness and on individual groups of species within 11 semideciduous forest fragments insoutheastern Brazil. We compared same-sized samples of 500 trees from 10 fragments<100 ha, allocated to three size categories, with three 500-tree samples collected in differentareas within a large forest, used as a reference forest. The variation in species richness,in the proportion of species/individuals in dispersal modes, and in the proportion of rarespecies was not related to fragment size. Nonetheless, comparisons between the mean valuesof these variables of each fragment size categories, using 95% confidence intervals,showed a wider range of variation within the category of small-sized fragments than inthe other size categories. NMS ordination plot also suggested the absence of a relationshipbetween fragment area and tree species composition. However, multiple regressions usingthe scores from the NMS ordination as response variables, and area and disturbance intensitiesas predictor variables, suggested that the interaction of area and disturbance mightbe a good predictor of species composition. Pre-existing environmental heterogeneityand geographical proximity also appeared to play a role in the variations of forest compositionamong the fragments studied. Our results demonstrated the high conservation value of small forest fragments.
Extinction risk is not randomly distributed among species but depends on species traits, their relationship to climate and land use, and corresponding threats by global change. While knowledge of which factors influence extinction risk is increasingly available for some taxonomic groups, this is still largely lacking for bryophytes. Here, we used random forest models to study which biological and ecological traits and bioclimatic variables are important predictors for extinction risk in European bryophytes. We hypothesized that species with a high extinction risk have a short life span, low dispersal capacities, and are more likely specialists than generalists in terms of ecological traits and bioclimate. Overall, we found bioclimatic variables to be the most important predictors for extinction risk, most notably precipitation seasonality, and related ecological traits such as continentality and elevational range. Important biological traits were plant size, life strategy and sporophyte production. In general, species living at climatic extremes and/or those with a narrow environmental range are more likely to be threatened. In addition, small-sized species and/or species with low reproductive effort and/or larger spore size are more likely to be threatened. Our findings imply that climate change may become an important driver of bryophytes extinction risk and that biological and ecological traits will be most relevant for species in coping with future threats.