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1.
European Bison (Bison bonasus) barely escaped extinction in the early 20th century and now only occur in small isolated herds scattered across Central and Eastern Europe. The species’ survival in the wild depends on identifying suitable habitat for establishing bison metapopulations via reintroductions of new herds. We assessed European Bison habitat across the Carpathian Mountains, a stronghold of European Bison and one of the only places where a viable bison metapopulation may be possible. We used maximum entropy models to analyze herd range maps and habitat use data from radio-collared bison to identify key habitat variables and map European Bison habitat across the entire Carpathian ecoregion (210,000 km2). Forest cover (primarily core and perforated forests) and variables linked to human disturbance best predict bison habitat suitability. Bison show no clear preference for particular forest types but prefer managed grasslands over fallow and abandoned fields. Several large, suitable, but currently unoccupied habitat patches exist, particularly in the eastern Carpathians. This available suitable habitat suggests that European Bison have an opportunity to establish a viable Carpathian metapopulation, especially if recent trends of declining human pressure and reforestation of abandoned farmland continue. Our results also confirm the suitability of a proposed Romanian reintroduction site. Establishing the first European Bison metapopulation would be a milestone in efforts to conserve this species in the wild and demonstrate a significant and hopeful step towards conserving large grazers and their ecological roles in human-dominated landscapes across the globe.  相似文献   

2.
The European bison Bison bonasus had been extirpated from the present territory of Ukraine by late 18th century. Since its restitution initiated in mid-sixties of the 20th century, seven bison herds occur in lowlands, and four along the Ukrainian Carpathians. Initial genetic structure of a herd has been evaluated on the basis of pedigree records on founder animals available for seven herds. Low bison numbers in particular herds, and considerable distances among their home ranges, do not create favourable conditions for further development of the population and natural gene exchange. Due to limited natural linkage among present bison ranges, and impenetrable barriers fragmenting lowland Ukraine, the establishment of a viable meta-population would require an active population management including the monitoring of its genetic structure, enrichment of gene pool through exchange of animals among herds, and facilitation of contacts with free ranging bison in neighbouring countries - Byelorussia, Poland and Romania.  相似文献   

3.
We investigated the effects of habitat patch size and connectivity on cryptogam richness on 288 calcareous boulders. The studied boulders were found to be a particularly suitable ‘metacommunity model system’ and allowed comparison of species richness among cryptogams with differing substrate specificity, life history and red list status. The dependence of species richness on boulder surface area was modelled using Arrhenius power model, and contrasts were analysed between connected and isolated boulders. Species richness was clearly related to boulder size, but the rates of increase of species richness with increasing boulder area (z-values) were highly variable among species groups. Highest value of z (1.17) was found for species with large propagules, and values around 0.5 were obtained for calciphilous and regionally red-listed species and z = 0.42 for perennials. The lowest value of z (0.27) occurred in calcicolous species while for all species, colonists, and species with small propagules the values were 0.3-0.4. The richness of all species was 11% higher on connected than isolated boulders, while connected boulders had 31% more of both calcicolous and regionally red-listed species and 19% more of colonists. The result suggests that in the investigated system that boulder size is a crucial determinant of cryptogam richness, and their spatial configuration in terms of connectivity may further contribute to cryptogam richness. The latter result lends support to the importance of metacommunity processes for the maintenance of cryptogam richness.  相似文献   

4.
We collected 1605 isopod individuals (eight species) and 671 diplopod individuals (17 species) in four primeval forests of the Western Carpathians, Central Slovakia, by leaf litter extraction. The forests are of different temperate deciduous forest types varying in tree species, aspect, elevation and soil characteristics. The oak forests, established on southwest oriented slopes at an elevation of 280-600 m, were characterized by Hyloniscus riparius, Porcellium conspersum, Enantiulus nanus and Ophioiulus pilosus. The beech forests, established on northeast oriented slopes at an elevation of 700-1100 m, were characterised by Ligidium hypnorum, Trachysphaera costata and Polyzonium germanicum. A remarkable increase of the total number of species and individuals occurred in both forest types adjacent to coarse woody debris (CWD). Woodlice density close to CWD was between 200 and 630 individuals m−2 (35-130 individuals m−2 distant from CWD); millipede density close to CWD ranged from 60 to 230 individuals m−2 (15-75 individuals m−2 distant from CWD). Species richness of both taxa close to CWD varied from 13 to 16 species m−2 (7-12 species m−2 distant from CWD). Thus, CWD has a significant influence on saprophages. However, structural components such as CWD and the amount of leaf litter did not significantly alter species assemblages. Species at sites distant from CWD were a subset of species at sites close to CWD. According to a canonical correspondence analysis (CCA), ‘forest type’ and ‘elevation within a slope’, as well as chemistry of the upper soil layer, i.e. ‘acidification’ and ‘nutrition’, strongly influenced species assemblages.  相似文献   

5.
Jzef Kukulak 《CATENA》2003,51(3-4):255-266
An abrupt change in sedimentary processes occurs in the alluvium of the San River headwaters in the Bieszczady mountains, Polish Eastern Carpathians. Older gravels are overlain, with a sharp boundary, by an extensive cover of sand and silt, which is enriched in wood debris, partly burned, at the base. The spatial distribution of the fine-grained alluvium, the wood debris composition and radiocarbon ages are best explained by a relatively sudden onset of deforestation and cultivation of the valley bottom and slopes in the middle of the second millennium. This corresponds well with palynological, archaeological and historical data on the agricultural colonisation of the valley.  相似文献   

6.
7.
Timing and causes of the present-day channel downcutting of Carpathian tributaries to the Vistula River are exemplified by a case study of the Raba River, a gravel-bed stream characterized by great variability of water stage and discharge. Up to 3 m of river incision has occurred since the beginning of the present century associated with an increase in stream power caused by river-control works, and reduction in bed-material load linked to changes in basin management. Gravel extraction from the channel and modifications in flood flows have increased rates of incision over the last thirty years.Lowering of ground-water levels on the valley floor, increase in river-bank susceptibility to erosion, decrease or cessation of overbank-sediment accretion, and impoverishment of plant and animal communities of riverside biotopes are the principal environmental effects of channel downcutting.  相似文献   

8.
J. PelíšeK 《Geoderma》1973,9(3):193-211
The Carpathians in Czechoslovakia form distinct mountain ranges. The major soil-forming rocks are flysch, so-called crystallinicum (granite, gneiss, phyllites) and mesozoic (mainly limestones), and young igneous rocks (andesites). Each of these kinds dominates a region with vertical soil zonality, and each vertical zone is also a zone of ecological conditions for biocoenoses, i.e. ecosystems.Soils of the vertical zones are characterized by different physical, chemical, biochemical, and microbial properties. Over a range from the lowlands to the high mountains, i.e. with rising elevation, the soil properties reveal the following trends: amounts of clay particles diminish and gravel content increases, soil-moisture content increases, temperature decreases, porosity increases, acidity and humus content increase, amounts of available nutrients diminish, C and N contents increase, C/N ratio increases, saturation of the sorption complex decreases, and biological activity decreases.  相似文献   

9.
Specialist species face higher extinction risks as a result of smaller, isolated populations with reduced gene flow. The large-footed myotis (Myotis macropus) is the only microbat in Australia specialised for foraging directly over water surfaces. Such highly specialised feeding ecology restricts the distribution of M. macropus to coastal regions and inland waterways. Using five novel and two existing nuclear microsatellite markers, we investigated genetic diversity within and among five M. macropus populations in Victoria. Significant genetic differentiation was detected between all populations. FST values between populations ranged from 0.02 to 0.24. We suggest that the movement of M. macropus throughout the landscape is constrained by the availability of permanent waterways and associated riparian habitats. These findings represent important considerations for the conservation of this specialist species and the management of riparian vegetation, particularly on private land.  相似文献   

10.
Recent declines in North American honeybee populations have highlighted the importance of native bee conservation, and the need for research on the ecological requirements of native bees in farmland. In this study, we investigated the value of hedgerows as foraging habitat for native bees in mosaics of small-scale agriculture and natural vegetation in two riparian landscapes in southeast Arizona, USA. In the summers of 2002 and 2003, we surveyed bees and flowers in four habitats: hedgerows, agricultural fields, woodlots, and native woodland. We asked: (1) How do hedgerows compare to other available habitats in bee abundance and species richness? (2) How does bee species composition in hedgerows compare to species composition in agricultural fields and woodland? (3) How do flower resources in hedgerows compare to those in fields and woodland?We found that hedgerows were attractive foraging habitat for native bees, especially in early summer, when hedgerows tended to have higher species richness than other agricultural or natural habitats. Cumulative species richness was highest in agricultural fields, although cumulative species richness did not significantly differ among fields, hedgerows, and woodland. While bee faunas overlapped among habitats, bee assemblages in hedgerows were more similar to those in woodland than to those in fields. The hedgerow herbaceous flora was roughly intermediate to that of fields and woodland; hedgerows also supported high densities of woodland-characteristic shrubs. These flowering shrubs were important in attracting bees that were otherwise uncommon in the landscape, including some species that are potentially valuable pollinators of agricultural crops.  相似文献   

11.
Although much work has been done on factors which influence the patterning of species and species trait assemblages in a variety of groups such as plants, vertebrates and invertebrates, few studies have been realized at a broad geographic scale. We analyzed patterns of relationships between species, species trait distribution/assembly, and environmental variables from the west of Europe to Slovakia, Poland and Sweden. We created a database by compiling traits and occurrence data of European collembolan species, using literature and personal field studies embracing a large range of environmental gradients (vertical stratification, habitat closure, humus form, soil acidity and moisture, temperature, rainfall, altitude) over which Collembola are supposed to be distributed. Occurrences of the 58 best-documented species, environmental variables and species traits allowed us to (i) show which environmental variables impact the distribution of the 58 species at broad scale and (ii) document to what extent environmental variables and species trait assemblages are related and which trends could be found in trait/environment relationships. The impact of vertical stratification, habitat closure, humus form, soil acidity, soil moisture, temperature, and to a lesser extent rainfall and altitude on species distribution, firstly revealed by indirect gradient analysis (correspondence analysis, CA), was further shown to be significant by direct gradient analysis (canonical correspondence analysis, CCA). RLQ analyses were performed to find linear combination of variables of table R (environmental variables) and linear combinations of the variables of table Q (species traits) of maximum covariance weighted by species occurrence data contained in table L. RLQ followed by permutation tests showed that all tested environmental variables apparently contributed significantly to the assemblages of the twelve species traits studied. A convergence was observed between traits related to vertical stratification and those related to habitat closure/aperture. Well-developed locomotory organs (furcula, legs), presence of sensorial organs sensitive to air movements and light (e.g. trichobothria and eye spots), spherical body, large body size, pigmentation (UV protection and signaling) and sexual reproduction largely occur in epigeic and open habitats, while most of woodland and edaphic habitats are characterized by short locomotory appendages, small body size, high number of defense organs (pseudocelli), presence of post-antennal organs and parthenogenesis. Climate and especially temperature exert an effect on the assemblage of traits that are mostly present above-ground and in open habitats. The contribution of combinations of some environmental variables to the occurrence of each species trait was tested by linear, logistic or multinomial regression (Generalized Linear Models). Vertical stratification, followed by temperature, played a dominant role in the variation of the twelve studied traits. Relationships between traits and environment tested here shows that it is possible to use some traits as proxies to identify potential ecological preferences or tolerances of invertebrate species. However, a significant part of species distribution remained unexplained, probably partly because some traits, like ecophysiological ones, or traits involved in biotic interactions (e.g. competition) were unavailable. The present work is thus a first step towards the creation of models predicting changes in collembolan communities. Further studies are required to inform ecophysiological traits, in order to complete such models. Moreover the niche width of species will have to be determined.  相似文献   

12.
The recent decline of the European starling in northern Europe has been associated with changes in agricultural land-use. We investigated how agricultural land-use affected starling habitat use and home-range size in a heterogeneous landscape in southern Sweden. Breeding starlings primarily foraged in pastures, a habitat with a high availability of potential food for nestlings. When the availability of pasture close to the nest was low, starlings increased their use of other permanently grass-covered habitats such as field margins and ditches. They also spent a larger proportion of their daytime flying because they visited more distant foraging areas. The further from the nest parents foraged, the higher was the probability that they foraged on a pasture. Feeding frequency of nestlings was negatively related to the distance from the nest parents foraged, but no consequences on nestling survival or growth were found. A lower breeding density at low local availability of pasture may compensate for lack of good foraging habitat. It is suggested that recent changes in the agricultural landscape may have increased the mismatch between the availability of good foraging areas and nest-sites. This might have contributed to the recent population decline of the starling in northern Europe by affecting both foraging habitat quality and flight costs paid by parents during breeding.  相似文献   

13.
Cereal steppe habitat is a low intensive system that is rapidly disappearing as a result of changes in agricultural practices, and has the highest number of bird species with an Unfavourable Conservation Status of any habitat in Europe. A logistic regression model showed that the lesser kestrel, a globally threatened species, prefers to forage close to colonies, selects fields with livestock and avoids tree plantations. The conservation of this species is dependent on maintenance of extensive agriculture characterised by a rotation of cereal and grazed fallow. Abandonment of traditional agriculture and recent changes in agri-environmental programme support, which favour afforestation, are jeopardising the future of cereal steppes. Agri-environment measures are likely to be the most effective means of retaining the specific characteristics of cereal steppe habitat.  相似文献   

14.
Assessment of habitat thresholds is a topical issue in ecology, both from theoretical and applied perspectives. We examined how forest structure influences selection of breeding habitat in the Eurasian treecreeper (Certhia familiaris). It is an old-growth forest passerine, which can be considered an umbrella species. Habitat selection data, covering five breeding seasons, were collected from a study area across three spatial scales: (a) territory core scale (a radius of 30 m), (b) territory scale (a radius of 200 m) and (c) large scale (a radius of 500 m). Logistic regression analyses revealed that the radii of 30 and 200 m from the nest were the most important spatial scales for the forest patch occupancy. A loss of forest habitat and a low circumference of stems within the territory decreased the probability of occupancy. There was a distinct threshold in the amount of forest cover on forest patch occupancy when the volume of timber was taken into account. At low timber volumes (0-151 m3/ha) the amount of forest cover was negatively related to the occupancy rate of forest patches. This negative relationship changed abruptly when the volume of timber exceeded 152 m3/ha, after which forest cover had a positive effect on the occupancy rate of forest patches. This is a new way to examine habitat thresholds in relation to forest cover. Furthermore, as debated in recent literature, treecreepers also tend to respond to habitat loss rather than to changes in habitat configuration, which stresses the need for habitat restoration and conservation. Moreover, our results emphasize the importance of within-territory structure over the characteristics of the habitat matrix in selection of breeding habitat.  相似文献   

15.
Parasites are thought to increase the risk of host extinction, but their dynamics in endangered species have not been well investigated. The free-living European bison population in Bia?owie?a Forest has recently been massively invaded by a blood-sucking nematode, Ashworthius sidemi. This nematode originated in Asia and was probably transmitted to Europe with the introduction of the sika deer. Here, we investigate the impacts of genetic factors (the Major Histocompatibility Complex class II genes responsible for extracellular parasite recognition) and management practices (supplementary feeding affecting winter population density) on the intensity of A. sidemi infections in bison. All but two out of 110 animals investigated between 2005 and 2009 were infected with A. sidemi, and the intensity of infection increased significantly with time. Due to a severe population bottleneck experienced by the bison, only four class II DRB alleles are retained in the Bia?owie?a population. We found that despite high sequence divergence, neither any of the alleles nor DRB heterozygosity was significantly associated with infection intensity. We did find, however, that winter density of bison herds was positively associated with infection intensity. Winter bison population densities were in turn predicted by the intensity of supplementary feeding.  相似文献   

16.
The stratigraphic rank of warming, distinguished in marine deposits as ‘marine oxygen isotope stage 7’ (MOIS 7) and recorded in terrestrial deposits as a palaeosol, has been discussed for a long time. The purpose of this paper is to describe the climate and environment of the time, determined from palaeopedological and palynological investigations of loess‐palaeosol sequences in the peri‐ and metha‐Carpathian zones, and to correlate these sequences with the Pleistocene stratigraphic units. The changes in chemical composition of the deposits were used to reconstruct the processes of chemical weathering and translocation of mobile elements during pedogenesis in three sections (Orzechowce, Galych and Velykyi Glybochok). The variability of the mean annual temperature and precipitation was estimated from the changes of elemental ratios resulting from chemical weathering and vegetation composition. From micromorphological analysis, the stages of palaeosol development and their transformation in cold periods were reconstructed. Pollen analysis carried out for the Velykyi Glyboczok, Maksymivka and Stari Kodaky sites, was used to reconstruct the vegetation cover and the temperature changes of the coldest and warmest months were calculated. The results indicate that the penultimate interglacial period, correlated with MOIS 7, comprised two warming periods separated by a profound cooling period. Warm periods were cooler than the last interglacial and more recent conditions. Vegetation was characterized by the co‐occurrence in changing proportions of patches of mixed forests and steppe vegetation. In the cold period, permafrost developed in places and cryogenic structures were formed. Regional differentiation of biotope environments, resulting from the increase in the continental nature of the climate towards the east, occurred during the whole interglacial period.  相似文献   

17.
18.
It is argued that the podzol of Silpho Moor could be converted under birch to a typical brown earth only if it could sustain an earthworm population with a Lumbricus terrestris biomass of not less than 100 g m?2. No worms of this species were found under experimental birch plots 30 yr old. The presence of podzolizing species in the ground vegetation; the low pH of the raw humus layer; the low Ca and N supply in the soil, litter and rainfall; and the impeded soil drainage lead to the conclusion that colonization by L. terrestris is unlikely.  相似文献   

19.
To clarify whether a particular group of soils of Archangelsk region (European N Russia) with humus‐rich topsoils exceeding the plowing zone supports an anthropogenic formation, four exemplary profiles were investigated. The investigation sites are characterized by distinct elevated surfaces, and the soils show thick toplayers of up to 60 cm with enrichment of soil organic matter and artifacts like brick, charcoal, and peat fragments, all indicating an anthropogenic origin. Increased phytolith amounts and high P contents of up to 800 mg kg–1 citric acid–soluble P and up to 1,400 mg kg–1 total P in the top horizons support an anthropogenic influence. These properties are very similar to the Plagganthrepts of NW Europe. The same is true regarding the main management aims: increasing soil fertility and overcoming the need of bedding materials. Having the required depths of the anthropogenic topsoil, the properties of the soils of the Archangelsk region allow a classification as Agrozems (Russian classification), Plaggenesche (German classification), and Plagganthrepts (US taxonomy). Since the high base saturation of the topsoil excludes a designation as plaggic horizon, the topsoil has to be considered as terric horizon, which leads to a classification as Terric Anthrosol according to WRB.  相似文献   

20.
We demonstrate how home range and habitat use analysis can inform landscape-scale conservation planning for the bobcat, Lynx rufus, in Vermont USA. From 2005 to 2008, we outfitted fourteen bobcats with GPS collars that collected spatially explicit locations from individuals every 4 h for 3–4 months. Kernel home range techniques were used to estimate home range size and boundaries, and to quantify the utilization distribution (UD), which is a spatially explicit, topographic mapping of how different areas within the home range are used. We then used GIS methods to quantify both biotic (e.g. habitat types, stream density) and abiotic (e.g. slope) resources within each bobcat’s home range. Across bobcats, upper 20th UD percentiles (core areas) had 18% less agriculture, 42% less development, 26% more bobcat habitat (shrub, deciduous, coniferous forest, and wetland cover types), and 33% lower road density than lower UD percentiles (UD valleys). For each bobcat, we used Akaike’s Information Criterion (AIC) to evaluate and compare 24 alternative Resource Utilization Functions (hypotheses) that could explain the topology of the individual’s UD. A model-averaged population-level Resource Utilization Function suggested positive responses to shrub, deciduous, coniferous forest, and wetland cover types within 1 km of a location, and negative responses to roads and mixed forest cover types within 1 km of a location. Applying this model-averaged function to each pixel in the study area revealed habitat suitability for bobcats across the entire study area, with suitability scores ranging between ?1.69 and 1.44, where higher values were assumed to represent higher quality habitat. The southern Champlain Valley, which contained ample wetland and shrub habitat, was a concentrated area of highly suitable habitat, while areas at higher elevation areas were less suitable. Female bobcat home ranges, on average, had an average habitat suitability score of near 0, indicating that home ranges consisted of both beneficial and detrimental habitat types. We discuss the application of habitat suitability mapping and home range requirements for bobcat conservation and landscape scale management.  相似文献   

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