Search results for "impact"
showing 10 items of 1703 documents
Land-use and climate related drivers of change in the reindeer management system in Finland: geography of perceptions
2021
Drivers of change in the reindeer management system are rather well-known. But when developing the gover-nance to support the traditional livelihoods, it is crucial to understand also practitioner perceptions. Systematic research on these is lacking. We analyzed the land-use and climate related drivers within the reindeer man-agement area (RMA) in Finland, and, using a perception geography approach, studied the herder perceptions towards these. We conducted an on-site questionnaire survey with herders from 51 herding districts. Factors directly affecting the welfare of reindeer were perceived as crucial by herders, for example basal icing affecting the forage availability, and land-use rela…
Are small protected habitat patches within boreal production forests effective in conserving species richness, abundance and community composition? :…
2021
Abstract Background In boreal zone forest management is changing and degrading forest habitats, which has caused declines in biodiversity. To mitigate these harmful effects in production forests, small-scale habitats with high biodiversity values have been protected within them. These habitats include woodland key habitats, and other small habitat patches protected by voluntary conservation actions. In this systematic review we synthesize the evidence on the value of small protected habitat patches (SPHP) within production forest landscapes for biodiversity. Review question: Are small protected habitat patches within boreal production forests effective in conserving species richness, abunda…
“Porţile de Fier/Iron Gates” Gorges Area (Danube) Fish Fauna
2014
AbstractAn important fisheries sector of the Danube, the “Iron Gates” area, was studied by famous naturalists along the history like Marsigli, Haeckel, Kner, Antipa and Bănărescu. After more than half a century after the last main publication in this area, the “Iron Gates” Danube sector suffered significant human impact, and an assessment of the fish fauna was needed. The paper summarizes the trend of fish species along the XIX to XXIst centuries, and reveals the appearance of new species. The study includes data from about 65 fish species, belonging to: Acipenseridae, Polyodontidae, Clupeidae, Salmonidae, Esocidae, Cyprinidae, Cobitidae, Siluridae, Ictaluridae, Anguillidae, Lotidae, Gaster…
Thymallus thymallus (Linnaeus, 1758), Ecological Status in Maramureş Mountains Nature Park (Romania)
2016
Abstract Thymallus thymallus is considered a species of significant protective importance within the Vişeu Watershed. The state of habitats characteristically inhabited by Thymallus thymallus within the Maramureş Mountains Nature Park is balanced between reduced (one third of the lotic sectors where the species was identified), average (one third) and good (one third). The excellent conservation status is currently missing for populations of this fish in the Vișeu Basin. Human impact types identified as contributing towards the decreasing state of Thymallus thymallus habitats and therefore populations in the studied area in comparison with its natural potential are: poaching, minor riverbed…
Environmental Characteristics and Anthropogenic Impact Jointly Modify Aquatic Macrophyte Species Diversity
2018
Species richness and spatial variation in community composition (i.e. beta diversity) are key measures of biodiversity. They are largely determined by natural factors, but also increasingly affected by anthropogenic factors. Thus, there is a need for a clear understanding of the human impact on species richness and beta diversity, the underlying mechanisms, and whether human-induced changes can override natural patterns. Here, we dissect the patterns of species richness, community composition and beta diversity in relation to different environmental factors as well as human impact in one framework: aquatic macrophytes in 66 boreal lakes in Eastern Finland. The lakes had been classified as h…
Severe effects of long-term drought on calcareous grassland seed banks
2018
Climate change models project shifts in precipitation patterns at regional and global scales. Increases in dry areas and the occurrence of drought predicted in future scenarios are likely to threaten grassland ecosystems. Calcareous grassland seed banks have proven to be resistant to short-term drought, but their responses to long-term drought are unknown. Here we show that 14 years of summer drought changed calcareous grassland seed bank composition, reducing its size and richness, and that these responses do not simply reflect patterns in the above-ground vegetation. Moreover, the effect of drought was larger on seed banks than on vegetation, and above-ground responses mediated by soil de…
Characteristics, Main Impacts, and Stewardship of Natural and Artificial Freshwater Environments: Consequences for Biodiversity Conservation
2020
International audience; In this overview (introductory article to a special issue including 14 papers), we consider all main types of natural and artificial inland freshwater habitas (fwh). For each type, we identify the main biodiversity patterns and ecological features, human impacts on the system and environmental issues, and discuss ways to use this information to improve stewardship. Examples of selected key biodiversity/ecological features (habitat type): narrow endemics, sensitive (groundwater and GDEs); crenobionts, LIHRes (springs); unidirectional flow, nutrient spiraling (streams); naturally turbid, floodplains, large-bodied species (large rivers); depth-variation in benthic commu…
Population and reproductive dynamics of the polychaete Pygospio elegans in a boreal estuary complex
2016
Pygospio elegans is an opportunistic, wide-spread spionid polychaete that reproduces asexually via fragmentation and can produce benthic and pelagic larvae, hence combining different developmental modes in one species. We documented the density, size distribution, and reproductive activity of P. elegans at four sites in the Danish Isefjord-Roskilde Fjord estuary complex, where all modes of reproduction were reported. We compared population dynamics of this species to environmental parameters such as salinity, temperature, and sediment characteristics (grain size, sorting, porosity, water content, organic content, C/N). We observed that new cohorts—resulting either from sexual or asexual rep…
Impact loading history modulates hip fracture load and location : A finite element simulation study of the proximal femur in female athletes
2018
Sideways falls impose high stress on the thin superolateral cortical bone of the femoral neck, the region regarded as a fracture-prone region of the hip. Exercise training is a natural mode of mechanical loading to make bone more robust. Exercise-induced adaptation of cortical bone along the femoral neck has been previously demonstrated. However, it is unknown whether this adaption modulates hip fracture behavior. The purpose of this study was to investigate the influence of specific exercise loading history on fall-induced hip fracture behavior by estimating fracture load and location with proximal femur finite element (FE) models created from magnetic resonance images (MRI) of 111 women w…
Rocking of rigid block on nonlinear flexible foundation
2017
Abstract The two prime models used currently to describe rocking of rigid bodies, the Housner’s model and the Winkler foundation model, can capture some of the salient features of the physics of this important problem. These two models involve either null or linear interaction between the block and the foundation. Hopefully, some additional aspects of the problem can be captured by an enhanced nonlinear model for the base-foundation interaction. In this regard, what it is adopted in this paper is the Hunt and Crossley’s nonlinear impact force model in which the impact/contact force is represented by springs in parallel with nonlinear dampers. In this regard, a proper mathematical formulatio…