Roodbergen M.,Wageningen University |
Roodbergen M.,University of Groningen |
van der Werf B.,Wageningen University |
Hotker H.,Michael Otto Institute im NABU
Journal of Ornithology | Year: 2012
In this review, we summarize available data on nest success, chick survival and reproductive output, and adult and juvenile survival of five meadow breeding waders in Europe: Eurasian Oystercatcher (Haematopus ostralegus), Northern Lapwing (Vanellus vanellus), Black-tailed Godwit (Limosa limosa), Eurasian Curlew (Numenius arquata), and Common Redshank (Tringa totanus). The survival data from the assembled studies did not show an overall decline in adult survival in any of these species. However, our meta-analyses on reproduction data show that chick survival declined strongly in the last 40 years in western Europe and that nest success declined in eastern Europe in the period 1995-2005, in Scandinavia in the period 1985-2005, and in western Europe in the period 1950-1980. Predation of nests has increased by c. +40% in all five species in western Europe during the last four decades. Results on reproductive output, the number of fledglings produced per breeding pair, were less clear. A decline was apparent in Eurasian Oystercatcher in the period 1963-2005; an initial decline in 1953-1990, but slight recent (1990-2006) recovery in Northern Lapwing; an initial decline in Black-tailed Godwit in the period 1985-1995, but again slight increase from 1995 onwards; no trend in Common Redshank (1992-2006) nor in Eurasian Curlew (1961-2006). In all five species the results indicate that present population declines are caused by a decrease in reproduction, not in adult survival, and that reproductive output is presently too low to compensate for adult mortality. © 2011 Dt. Ornithologen-Gesellschaft e.V.
Salewski V.,Michael Otto Institute im NABU |
Siebenrock K.-H.,Max Planck Institute for Ornithology (Radolfzell) |
Hochachka W.M.,Cornell University |
Woog F.,Staatliches Museum fur Naturkunde Stuttgart |
Fiedler W.,Max Planck Institute for Ornithology (Radolfzell)
PLoS ONE | Year: 2014
Changes in morphology have been postulated as one of the responses of animals to global warming, with increasing ambient temperatures leading to decreasing body size. However, the results of previous studies are inconsistent. Problems related to the analyses of trends in body size may be related to the short-term nature of data sets, to the selection of surrogates for body size, to the appropriate models for data analyses, and to the interpretation as morphology may change in response to ecological drivers other than climate and irrespective of size. Using generalized additive models, we analysed trends in three morphological traits of 4529 specimens of eleven bird species collected between 1889 and 2010 in southern Germany and adjacent areas. Changes and trends in morphology over time were not consistent when all species and traits were considered. Six of the eleven species displayed a significant association of tarsus length with time but the direction of the association varied. Wing length decreased in the majority of species but there were few significant trends in wing pointedness. Few of the traits were significantly associated with mean ambient temperatures. We argue that although there are significant changes in morphology over time there is no consistent trend for decreasing body size and therefore no support for the hypothesis of decreasing body size because of climate change. Non-consistent trends of change in surrogates for size within species indicate that fluctuations are influenced by factors other than temperature, and that not all surrogates may represent size appropriately. Future analyses should carefully select measures of body size and consider alternative hypotheses for change. © 2014 Salewski et al.
PubMed | Staatliches Museum fur Naturkunde Stuttgart, Michael Otto Institute im NABU, Cornell University and Max Planck Institute for Ornithology (Radolfzell)
Type: Journal Article | Journal: PloS one | Year: 2014
Changes in morphology have been postulated as one of the responses of animals to global warming, with increasing ambient temperatures leading to decreasing body size. However, the results of previous studies are inconsistent. Problems related to the analyses of trends in body size may be related to the short-term nature of data sets, to the selection of surrogates for body size, to the appropriate models for data analyses, and to the interpretation as morphology may change in response to ecological drivers other than climate and irrespective of size. Using generalized additive models, we analysed trends in three morphological traits of 4529 specimens of eleven bird species collected between 1889 and 2010 in southern Germany and adjacent areas. Changes and trends in morphology over time were not consistent when all species and traits were considered. Six of the eleven species displayed a significant association of tarsus length with time but the direction of the association varied. Wing length decreased in the majority of species but there were few significant trends in wing pointedness. Few of the traits were significantly associated with mean ambient temperatures. We argue that although there are significant changes in morphology over time there is no consistent trend for decreasing body size and therefore no support for the hypothesis of decreasing body size because of climate change. Non-consistent trends of change in surrogates for size within species indicate that fluctuations are influenced by factors other than temperature, and that not all surrogates may represent size appropriately. Future analyses should carefully select measures of body size and consider alternative hypotheses for change.
PubMed | University of Turku, Swiss Ornithological Institute, Michael Otto Institute im NABU, Palacky University and 2 more.
Type: | Journal: Scientific reports | Year: 2016
Over decades it has been unclear how individual migratory songbirds cross large ecological barriers such as seas or deserts. By deploying light-level geolocators on four songbird species weighing only about 12 g, we found that these otherwise mainly nocturnal migrants seem to regularly extend their nocturnal flights into the day when crossing the Sahara Desert and the Mediterranean Sea. The proportion of the proposed diurnally flying birds gradually declined over the day with similar landing patterns in autumn and spring. The prolonged flights were slightly more frequent in spring than in autumn, suggesting tighter migratory schedules when returning to breeding sites. Often we found several patterns for barrier crossing for the same individual in autumn compared to the spring journey. As only a small proportion of the birds flew strictly during the night and even some individuals might have flown non-stop, we suggest that prolonged endurance flights are not an exception even in small migratory species. We emphasise an individuals ability to perform both diurnal and nocturnal migration when facing the challenge of crossing a large ecological barrier to successfully complete a migratory journey.
Salewski V.,Michael Otto Institute im NABU |
Hochachka W.M.,Cornell University |
Flinks H.,Am Kuhm 19
Journal of Ornithology | Year: 2014
Declining body size has been suggested to be a response of animals to global warming, but analyses of time series have led to contradictory results. One problem is that each trait related to body size may vary in response to factors other than temperature and independently of size. We analyse trends of three morphological traits of a passerine bird species: the Stonechat Saxicola torquata. Wing lengths were increasing and tail length mostly decreasing between 1989 and 2012. Variation in tarsus length showed no consistent trend. Wing length increased with increasing temperature. Concomitant decreasing tail length suggests, however, that increasing wing length cannot be explained by increasing temperatures during the study period. As tarsus length is a surrogate for overall size, we argue that there was no detectable trend in body size. Wing and tail length are related to flight performance, and increasing wing and decreasing tail length could be indicative of selection for more effective flight, related to either longer migration distances or increased predation pressure. The first scenario is unlikely given the strong suggestions of reduced migratory activity in birds as a response to climate change. The density of the Sparrowhawk Accipiter nisus recently increased almost tenfold in the study area, but the hypothesis of changing morphology as a response to increasing predation pressure remains to be tested. Our study suggests, however, that linking fluctuating lengths in single morphological traits to body size change as a response to global warming may be premature when alternative hypotheses are not considered. © 2014 Dt. Ornithologen-Gesellschaft e.V.
Kupper C.,Harvard University |
Kupper C.,University of Sheffield |
Edwards S.V.,Harvard University |
Kosztolanyi A.,Eötvös Loránd University |
And 11 more authors.
Molecular Ecology | Year: 2012
Gene flow promotes genetic homogeneity of species in time and space. Gene flow can be modulated by sex-biased dispersal that links population genetics to mating systems. We investigated the phylogeography of the widely distributed Kentish plover Charadrius alexandrinus. This small shorebird has a large breeding range spanning from Western Europe to Japan and exhibits an unusually flexible mating system with high female breeding dispersal. We analysed genetic structure and gene flow using a 427-bp fragment of the mitochondrial (mtDNA) control region, 21 autosomal microsatellite markers and a Z microsatellite marker in 397 unrelated individuals from 21 locations. We found no structure or isolation-by-distance over the continental range. However, island populations had low genetic diversity and were moderately differentiated from mainland locations. Genetic differentiation based on autosomal markers was positively correlated with distance between mainland and each island. Comparisons of uniparentally and biparentally inherited markers were consistent with female-biased gene flow. Maternally inherited mtDNA was less structured, whereas the Z-chromosomal marker was more structured than autosomal microsatellites. Adult males were more related than females within genetic clusters. Taken together, our results suggest a prominent role for polyandrous females in maintaining genetic homogeneity across large geographic distances. © 2012 Blackwell Publishing Ltd.
Hotker H.,Michael Otto Institute im NABU |
Dierschke V.,Tonnhauser Dorfstrasse 20 |
Flade M.,Dorfstrasse 60 |
Leuschner C.,University of Gottingen
Natur und Landschaft | Year: 2014
This article documents changes in the avifauna of Germany's farmland in the course of agricultural intensification, mainly since the 1980s but less severely also since the 1950s. The study is based on the breeding bird monitoring programme in Germany and the comparison of old and more recent censuses of breeding bird densities. Large population declines occurred in the 1970s and 1980s, followed by more stable, but greatly reduced populations in the 1990s. With the abandonment of the set-aside requirement of the CAP in 2007 and intensified conversion of grassland to arable land, increased population declines were recorded again from 2008 onwards, particularly in the grasslands. Various causes are responsible for the decline. They include the loss of grassland area, the shift from summer to winter cereals, the general increase in field size, the greater use of pesticides and fertilizers, grassland management intensification and reduced crop diversity. Biodiversity conservation efforts in agricultural landscapes in the past were unable to halt the loss because agri-environmental measures (AEM) covered only a very small area of the cropland and many habitat management measures in grasslands were not sufficiently efficient, mostly due to lack of personnel. Moreover, the success of AEM has been recently monitored in only three of Germany's 16 states. New, more efficient and locally-adapted conservation approaches in the farmland are urgently needed. These should include best-practice demonstration projects on conventional farms where measures to increase biodiversity are implemented while farm profitability is maintained. © 2014. Kohlhammer, Stuttgart.
Schrautzer J.,University of Kiel |
Fichtner A.,University of Kiel |
Huckauf A.,University of Kiel |
Rasran L.,Michael Otto Institute im NABU |
Jensen K.,University of Hamburg
Flora: Morphology, Distribution, Functional Ecology of Plants | Year: 2011
The orchid Dactylorhiza incarnata (L.) Soó is a highly polymorphic species listed as endangered in many regional red lists of Central Europe and Scandinavia. The dramatic decline of its populations during recent decades has been caused by the loss and degradation of their natural and semi-natural habitats (fens and wet meadows, respectively) as a result of secondary succession following intensification or abandonment of traditional land use.In this study, we analysed the effects of abandonment and re-introduction of mowing on the long-term (28 years) population dynamics of Dactylorhiza incarnata at Lake Barsbek in northern Germany. In this area, to preserve a remaining population of D. incarnata, an annual mowing regime was re-established in 1981 on site M-1 of the investigated plots after a period of abandonment. Annual mowing was introduced on a second site, M-2, in 1987. Two- to three-year mowing was introduced on a third site, M-3. Site A, abandoned since 1970, was used as a reference. On each of these sites, flowering individuals were counted once a year. Population structure and accompanying vegetation were recorded simultaneously. In 2006, light measurements were carried out in the mowed areas.The D. incarnata population at M-1 increased exponentially during the first 10 years after re-introduction of mowing. Pronounced decreases in the number of flowering individuals were recorded in 1997 and 2003. Population dynamics at M-2 generally resembled the temporal development at M-1. D. incarnata disappeared on site A during the investigation period, while vegetation height and litter layer increased by 60 and 100%, respectively. D. incarnata was able to withstand reduced light availability to a certain extent by increasing its vertical growth (shade avoidance). It is concluded that the maintenance of D. incarnata populations in Central Europe requires continuation or re-establishment of wet meadow management. On previously abandoned sites, an initially higher mowing frequency is recommended. Management intensity can be reduced after phytomass production of the vegetation has declined. © 2011 Elsevier GmbH.
Dominance of particular weed species in relation to nature conservation management on permanent grasslands (review) [Problempflanzen im Fokus des Naturschutzmanagements von Dauergrünlandflächen (Literaturstudie)]
Rasran L.,Michael Otto Institute im NABU |
Jeromin H.,Michael Otto Institute im NABU
Telma | Year: 2010
In recent time agricultural use of large areas of moist and wet grasslands on fens, bogs and marsh soils has been changed according to the guidelines of nature conservation. A consequence of such changes (lower intensity of grazing/mowing, reduction of fertilizer, rewetting) is sometimes a rapid spread and dominance of some specific weeds (Soft rush -Juncus effusus, Tussock grass-Deschampsia cespitosa, Docks - Rumex crispus, R. obtusifolius, Marsh horsetail - Equisetum palustre). These developments are from the viewpoint of nature conservation undesirable and make the further management of the areas difficult. The current review deals with reasons and mechanisms for the rapid invasion of wet grasslands by the above mentioned weed species, methods of weed control and the reconcilability of these methods with aims and practices of nature conservation.
Hotker H.,Michael Otto Institute im NABU
Vogelwarte | Year: 2015
Most populations of wader species breeding on wet grassland in Western and Central Europe have decline4 over the past decades. In Germany, Northern Lapwing Vanellus vanellus, Dunlin subspecies Calidris alpina schinzii, Ruff Philomachus pugnax, Common Snipe Gallinago gallinago, Eurasian Curlew Numenius arquata, Black-tailed Godwit Limosa limosa and Redshank Tringa totanus are red listed. Survival rates of adult and first year birds of different populations of European Oystercatchers Haematopus ostralegus, Northern Lapwings, Eurasian Curlews, Black-tailed Godwits and Redshanks were almost stable since the 1970ies, whereas breeding success rates (numbers of fledglings per pair) decreased over the same period. Threats present at the breeding sites thus are more likely to have caused the declines than threats present during the non-breeding season. © DO-G, IfV, MPG 2015.