Search results for "Study"
showing 10 items of 15483 documents
Long-term changes in winter abundance of the barbastelle Barbastella barbastellus in Poland and the climate change - Are current monitoring schemes s…
2020
Warmer winters may lead to changes in the hibernation behaviour of bats, such as the barbastelle Barbastella barbastellus, which prefers to hibernate at low temperatures. The species is also known for its large annual fluctuations in the number of wintering individuals, so inference about population trends should be based on long-term data. Prior to 2005, analyses indicated stable or even increasing barbastelle population in Poland. We analysed the results of 13 winter bat counts (2005–2017) of the species from 15 of the largest hibernacula, and additional site of 47 small bunkers, in Poland. The total number of wintering individuals remained stable during the study period, because the barb…
Interspecific variation in the relationship between clutch size, laying date and intensity of urbanization in four species of hole-nesting birds
2016
Marie Vaugoyeau [et al.]
Reproduction ecology of the recently invasive snake Hemorrhois hippocrepis on the island of Ibiza
2019
Abstract Knowing the causes of biological invasion success can be relevant to combat future invasive processes. The recent invasion of the horseshoe whip snake Hemorrhois hippocrepis on the island of Ibiza provides the opportunity to compare natural history traits between invasive and source populations, and to unravel what makes this snake a successful invader that is threatening the only endemic vertebrate of the island, Podarcis pityusensis. This study compares the basic reproductive traits of mainland native and invasive populations of the snake. Our results revealed that invasive populations were characterized by female maturity at a smaller size, extended reproductive period, and much…
Geographical variation in egg mass and egg content in a passerine bird
2011
Reproductive, phenotypic and life-history traits in many animal and plant taxa show geographic variation, indicating spatial variation in selection regimes. Maternal deposition to avian eggs, such as hormones, antibodies and antioxidants, critically affect development of the offspring, with long-lasting effects on the phenotype and fitness. Little is however known about large-scale geographical patterns of variation in maternal deposition to eggs. We studied geographical variation in egg components of a passerine bird, the pied flycatcher (Ficedula hypoleuca), by collecting samples from 16 populations and measuring egg and yolk mass, albumen lysozyme activity, yolk immunoglobulins, yolk and…
Early developmental conditions affect stress response in juvenile but not in adult house sparrows (Passer domesticus).
2009
6 pages; International audience; The short- and long-term consequences of developmental conditions on fitness have received growing attention because the environmental conditions during early life may influence growth, condition at independence, recruitment, reproductive success or survival. We tested here, in a natural house sparrow population, if early conditions during nestling stage affected the stress response of the birds (i) shortly after fledging and (ii) next year, during their first breeding. We experimentally manipulated brood size to mimic different rearing conditions, creating reduced (-2 chicks) and enlarged broods (+2 chicks), while in a third group brood size was not manipul…
Colour variation and alternative reproductive strategies in females of the Common lizard Lacerta vivipara
2007
Within-sex colour variation is a widespread phenomenon in animals that often plays a role in social selection. In males, colour variation is typically associated with the existence of alternative reproductive strategies. Despite ecological conditions theoretically favourable to the emergence of such alternative strategies in females, the social significance of colour variation in females has less commonly been addressed, relative to the attention given to male strategies. In a population of the common lizard, females display three classes of ventral colouration: pale yellow, orange and mixed. These ventral colours are stable through individual's life and maternally heritable. Females of dif…
Substantial decline of Northern European peatland bird populations: Consequences of drainage
2017
Northern European peatlands are important habitats for biological conservation because they support rich biodiversity and unique species compositions. However, historical management of peatland habitats has had negative consequences for biodiversity and their degradation remains a major conservation concern. Despite increasing awareness of the conservation value of peatlands, the statuses and ecological requirements of peat land species have remained largely understudied. Here, we first analysed temporal trends of Northern European peatland birds to document the status of their populations using bird data from five different countries. Second, we used Finnish monitoring data to assess habit…
Drivers of Spruce Bark Beetle (Ips typographus) Infestations on Downed Trees after Severe Windthrow
2020
Research Highlights: Bark beetles are important agents of disturbance regimes in temperate forests, and specifically in a connected wind-bark beetle disturbance system. Large-scale windthrows trigger population growth of the European spruce bark beetle (Ips typographus L.) from endemic to epidemic levels, thereby allowing the killing of Norway spruce trees over several consecutive years. Background and Objectives: There is a lack of evidence to differentiate how outbreaks are promoted by the effects of environmental variables versus beetle preferences of trees from endemic to outbreak. However, little is known about how individual downed-tree characteristics and local conditions such as tre…
Potential Solar Radiation as a Driver for Bark Beetle Infestation on a Landscape Scale
2019
In recent decades, Norway spruce (Picea abies L. Karst.) forests of the High Tatra Mountains have suffered unprecedented tree mortality caused by European spruce bark beetle (Ips typographus L.). Analysis of the spatiotemporal pattern of bark beetle outbreaks across the landscape in consecutive years can provide new insights into the population dynamics of tree-killing insects. A bark beetle outbreak occurred in the High Tatra Mountains after a storm damaged more than 10,000 ha of forests in 2004. We combined yearly Landsat-derived bark beetle infestation spots from 2006 to 2014 and meteorological data to identify the susceptibility of forest stands to beetle infestation. We found that digi…
Impacts of chitinase-transformed silver birch on leaf decomposition and soil organisms
2004
Genetically manipulated silver birch (Betula pendula) leaves were used in microcosms experiments to evaluate their impacts on different groups of decomposing soil fauna. Birches were transformed to produce chitinase IV from sugar beet. We compared decomposition rates of leaves, growth and reproduction of soil fauna deriving nutrition from these leaves. Population numbers of collembolans (Folsomia candida and Lepidocyrtus lignorum) and nematodes were measured and decomposition rates of the birch leaves were recorded. Woodlice (Porcellio scaber) juveniles living in the microcosms were weighed at 2- to 4-week intervals to determine growth rate. This study revealed that birch leaves manipulated…