10 research outputs found
Ecological and life history correlates of changes in avian migration timing in response to climate change
Spring migration of birds in many parts of the world has advanced as the climate has become warmer. Variation in advancement among species has been proposed to correlate with geography and life history features, but individual studies have reported variable results, and general patterns have been elusive. In a quantitative review of data from 389 bird species sampled at 69 European and 23 North American localities, we evaluated associations between change in the timing of migration and life history (body size, molt, broodedness), ecology (habitat, diet, nest position), and geography. We confirmed that spring migration advanced: -0.214 d yr-1 (95% CI: -0.266, -0.162) for first-arriving individuals and -0.104 d yr-1 (-0.139, -0.071) for the median date of passage. The rate of change in autumn was more variable: 0.090 d yr-1 (0.002, 0.176) delay for median passage and 0.019 d yr-1 (-0.175, 0.204) delay for the date of last departure. The response during spring was weaker in the far north and in species that migrate long distances to the wintering area. Autumn migration became increasingly delayed in species that are large-bodied, molt before departure, and that feed on seeds, insects, or fruits. Variation among species, especially during autumn, was associated in part with constraints surrounding the timing of the postnuptial molt. The results suggest that ecological and life history features of species may influence their ability to respond to climate change
Kleinsäuger mit Haarproben zuverlässig bestimmen
Um das Vorkommen der Schweizer Kleinsäugetiere zu untersuchen, müssen diese lebend gefangen und bestimmt werden. Gewisse ähnliche Arten lassen sich jedoch morphologisch nicht genau unterscheiden. Für eine sichere Artbestimmung ist deshalb bei einigen Arten eine DNA-Analyse unumgänglich. Die Entnahme von Haarproben ermöglicht eine für das Tier schnelle und schonende Gewinnung von DNA
Auerhuhnprojekt Teufimatt : Monitoring der Wirkung forstlicher Aufwertungsmassnahmen auf Raufusshuhnvorkommen und Nahrungsangebot fĂĽr KĂĽken
Eine Veröffentlichung der Fachstelle Wildtier- und Landschaftsmanagement WILMA im Auftrag der Abteilung Natur, Jagd und Fischerei / lawa Luzern
Nahrungsangebot fĂĽr AuerhuhnkĂĽken : der Einfluss forstlicher Aufwertungen
Chick food availability after forestry activities in favour of capercaillie
Conservation measures to further the remaining capercaillie populations in Switzerland focus mainly on improving habitat quality of the forests. So far, programs to survey the effect of these forestry measures have been restricted to changes in forest structure and capercaillie presence on the treated areas. Potential changes in arthropod food availability, a key factor for the habitat quality for chicks in their first weeks of life, however, have not been assessed systematically in Central European habitats. We measured the biomass of arthropods in four habitat types: dense, semiopen and open stands and inner forest edges. In our study area in the Swiss Prealps, these habitat types resulted from logging activities in twelve cable-way lines between 2008 and 2011 that were carried out with the aim to improve habitat quality for capercaillie. Arthropod availability varied strongly between plots and high numbers of individuals could be observed in all four habitat types. Coleoptera accounted for more than half of the total dry weight of the catch. Summing up the three most important arthropod groups for the chick diet as reported in literature (spiders, ants and lepidoptera larvae), open stands, forest edges and semiopen stands yielded higher arthropod biomasses than the dense stands that had not been treated in the logging campaigns. In this case study, habitat improvement measures increased the arthropod food supply, and thus probably improved the conditions for capercaillie chicks in the first weeks of their development.</jats:p
Fish population genetic structure shaped by hydroelectric power plants in the upper Rhine catchment
The Rhine catchment in Switzerland has been transformed by a chain of hydroelectric power stations. We addressed the impact of fragmentation on the genetic structure of fish populations by focusing on the European chub (Squalius cephalus). This fish species is not stocked and copes well with altered habitats, enabling an assessment of the effects of fragmentation per se. Using microsatellites, we genotyped 2133 chub from 47 sites within the catchment fragmented by 37 hydroelectric power stations, two weirs and the Rhine Falls. The shallow genetic population structure reflected drainage topology and was affected significantly by barriers to migration. The effect of power stations equipped with fishpasses on genetic differentiation was detectable, albeit weaker than that of man-made barriers without fishpasses. The Rhine Falls as the only long-standing natural obstacle (formed 14 000 to 17 000 years ago) also had a strong effect. Man-made barriers also exacerbated the upstream decrease in allelic diversity in the catchment, particularly when lacking fishpasses. Thus, existing fishpasses do have the desired effect of mitigating fragmentation, but barriers still reduce population connectivity in a fish that traverses fishpasses better than many other species. Less mobile species are likely to be affected more severely.ISSN:1752-4571ISSN:1752-456
Data from: Fish population genetic structure shaped by hydroelectric power plants in the upper Rhine catchment
The Rhine catchment in Switzerland has been transformed by a chain of hydroelectric power stations. We addressed the impact of fragmentation on the genetic structure of fish populations by focusing on the European chub (Squalius cephalus). This fish species is not stocked and copes well with altered habitats, enabling an assessment of the effects of fragmentation per se. Using microsatellites, we genotyped 2133 chub from 47 sites within the catchment fragmented by 37 hydroelectric power stations, two weirs and the Rhine Falls. The shallow genetic population structure reflected drainage topology and was affected significantly by barriers to migration. The effect of power stations equipped with fishpasses on genetic differentiation was detectable, albeit weaker than that of man-made barriers without fishpasses. The Rhine Falls as the only long-standing natural obstacle (formed 14 000 to 17 000 years ago) also had a strong effect. Man-made barriers also exacerbated the upstream decrease in allelic diversity in the catchment, particularly when lacking fishpasses. Thus, existing fishpasses do have the desired effect of mitigating fragmentation, but barriers still reduce population connectivity in a fish that traverses fishpasses better than many other species. Less mobile species are likely to be affected more severely