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1.
Capsule Negative forest edge effects were detected for Willow Ptarmigan (Red Grouse) Lagopus lagopus and Dunlin Calidris alpina.

Aims To investigate the effects of distance to forest on the abundance and changes in abundance of four key peatland breeding bird species, and to measure changes in predatory bird numbers, in the peatlands of northern Scotland.

Methods Bird surveys were carried out in 2000 at 34 plots, covering 197 km2 of peatland, and 80 forestry point‐count sites, first surveyed in 1988. Habitat data were also collected in 2000. We used multi‐model inference to investigate the associations between forest distance and other habitat variables, and the abundance, and changes in abundance, of four bird species of economic or conservation importance: Red Grouse, European Golden Plover Pluvialis apricaria, Dunlin and Common Greenshank Tringa nebularia.

Results There was strong evidence that distance to forest was negatively associated with Dunlin abundance and changes in Red Grouse abundance, but only weak evidence for negative associations with Golden Plover abundance and changes in Dunlin abundance. There was no evidence of a forest distance effect on Greenshank. Among predatory birds, there were no significant increases either on peatland plots or in new forestry plantations.

Conclusions This study provides evidence that, for a given habitat quality, Dunlin densities are lower, and Red Grouse declines more likely, near to forest edges, but weak evidence only that Dunlin declines are more likely, and Golden Plover abundance lower, near to forests. These results suggest that for at least two key peatland breeding birds, forest removal is likely to benefit birds breeding on adjacent unafforested peatland.  相似文献   

2.
Summary

Scottish peatlands have suffered loss and damage for centuries through cutting for fuel and agricultural and forestry practices. The ombrogenous blanket mires of Caithness and Sutherland (the ‘Flow Country’) are of international importance for the range and quality of their peatland types and vegetation, and their breeding bird populations. Loss of this habitat in the last decade, due to rapid expansion of forestry, caused great concern which was expressed by voluntary and statutory nature conservation organizations and the national media. Government at both national and local levels responded with changes in forestry policies, protection of large areas of peatland and by a land-use strategy which divides the area into four forestry policy zones.  相似文献   

3.
We compared wintering bird communities and their habitats among three shoals at Jiuduansha, a newly-formed wetland in the Yangtze River estuary. The highest species richness and diversity were recorded in Shangsha, which is the highest shoal, and the highest abundance and lowest species diversity were recorded in Xiasha, which is the lowest shoal. Shangsha had the largest abundance of perching birds whereas Xiasha was the most abundant in waterbirds. Bird assemblages showed different associations with the different habitat types—perching birds were favored by reed (Phragmites australis) communities, shallow water foragers and dabbling ducks preferred sea-bulrush (Scirpus mariqueter) communities, and moist-soil foragers and gulls showed a preference for bare intertidal zones. All bird assemblages, however, avoided the smooth cordgrass (Spartina alterniflora) communities, which are dominated by an alien invasive plant. The composition of avian communities was related to habitat types at the three shoals. Our results suggest that the newly-formed tidelands can provide suitable habitats for waterbirds and that the lower tidelands can attract more waterfowl than the higher tidelands. Because the shoal with low species diversity could have exclusive bird species, conservation efforts should not concentrate only on the area with high species diversity. The estuarine wetlands should be considered as a whole when conservation strategies are designed. The alien invasive plant should, moreover, be effectively controlled, to provide suitable habitats for birds.  相似文献   

4.
Capsule Habitats in lowland South Iceland sustain bird populations of international importance, with highest densities in wet habitats.

Aims In areas important for biodiversity there is an urgent need to assess large-scale variation in the biodiversity value of habitats to inform management. We carried out a large-scale survey to assess the conservation value of sub-arctic, Icelandic bird habitats.

Methods Bird counts were carried out on 200 transects in the five most common vegetated habitat types in South Iceland. Based on these counts, breeding bird density and diversity were compared between habitats and total population sizes of common species in these habitats were calculated.

Results Overall, eight species (seven waders and Meadow Pipit) composed over 95% of all birds counted. The combined density of those species exceeded 275 birds/km2 in all habitats. The two wettest habitat types had the highest density of birds.

Conclusion Wet habitats in lowland South Iceland held particularly high densities of breeding birds, notably waders, which constitute populations of international importance. Wet habitat types are generally of higher value for more species, than dryer ones.  相似文献   

5.
The habitat use and seasonal migratory pattern of birds in Ethiopia is less explored as compared to diversity studies. To this end, this study aimed at investigating the patterns of distribution related to seasonality and the effect of habitat characteristics (elevation, slope, and average vegetation height) on habitat use of birds of Wondo Genet Forest Patch. A stratified random sampling design was used to assess the avian fauna across the four dominant habitat types found in the study area: natural forest, wooded grassland, grassland, and agroforestry land. A point transect count was employed to investigate avian species richness and abundance per habitat type per season. Ancillary data, such as elevation above sea level, latitude and longitude, average vegetation height, and percent slope inclination, were recorded with a GPS and clinometers per plot. A total of 33 migratory bird species were recorded from the area, of which 20 species were northern (Palearctic) migrants while 13 were inter‐African migrants. There was a significant difference in the mean abundance of migratory bird species between dry and wet seasons (t = 2.13, p = .038, df = 44). The variation in mean abundance per plot between the dry and wet seasons in the grassland habitat was significant (t = 2.35, p = .051, df = 7). In most habitat types during both dry and wet seasons, omnivore birds were the most abundant. While slope was a good predictor for bird species abundance in the dry season, altitude and average vegetation height accounted more in the wet season. The patch of forest and its surrounding is an important bird area for migratory, endemic, and global threatened species. Hence, it is conservation priority area, and the study suggests that conservation coupled with ecotourism development is needed for its sustainability.  相似文献   

6.
In the Indian subcontinent there is hardly any study that compares the bird community structure of urban/suburban areas with those of forest habitat. The present survey identified diverse assemblages of birds in the Pauri district at different elevations. A total of 125 bird species belonging to 40 families including two least count species (Lophura leucomelanos and Pucrasia marcolopha) were recorded during this survey in the forest and urbanized habitats of Pauri District (Garhwal Hiamalaya) of Uttarakhand state, India. The high elevation (Pauri 1600–2100 m a.s.l.), mid elevation (Srikot-Khanda 900–1300 m a.s.l.) and low elevation (Srinagar 500–900 m a.s.l.) contributed 88.8%, 63.2% and 58.4% of the total species respectively. Rarefaction analysis and Shannon diversity index showed that the high elevation forest habitat had highest bird species richness (BSR) and bird species diversity (BSD) followed by the mid and then the low elevation forests. BSR and BSD fluctuated across seasons at all elevations but not across habitat types. Present study provides a base line data about avian community composition in urbanized and natural habitats along altitudinal gradient in the study area. This information may be useful to the conservation biologists for the better management and conservation of the avifauna in the Western Himalaya, a part of one of the hot biodiversity spots of the world.  相似文献   

7.
Peatlands in Australia and New Zealand are composed mainly of Restionaceous and Cyperaceous peats, although Sphagnum peat is common in wetter climates (Mean Annual Precipitation > 1,000 mm) and at higher altitudes (>1,000 m). Experimental trials in two contrasting peatland types—fire‐damaged Sphagnum peatlands in the Australian Alps and cutover restiad bogs in lowland New Zealand—revealed similar approaches to peatland restoration. Hydrological restoration and rehydration of drying peats involved blocking drainage ditches to raise water tables or, additionally in burnt Sphagnum peatlands, peat‐trenching, and the use of sterilized straw bales to form semipermanent “dam walls” and barriers to spread and slow surface water movement. Recovery to the predisturbance vegetation community was most successful once protective microclimates had been established, either artificially or naturally. Specifically, horizontally laid shadecloth resulted in Sphagnum cristatum regeneration rates and biomass production 3–4 times that of unshaded vegetation (Australia), and early successional nurse shrubs facilitated establishment of Sporadanthus ferrugineus (New Zealand) within 2–3 years. On severely burnt or cutover sites, a patch dynamic approach using transplants of Sphagnum or creation of restiad peat “islands” markedly improved vegetation recovery. In New Zealand, this approach has been scaled up to whole mine‐site restoration, in which the newly vegetated islands provide habitat and seed sources for plants and invertebrates to spread onto surrounding areas. Although a vegetation cover can be established relatively rapidly in both peatland types, restoration of invertebrate communities, ecosystem processes, and peat hydrological function and accumulation may take many decades.  相似文献   

8.
Capsule Flowers of an invasive plant species are more visited by native birds than flowers of ornithophilous endemic plants.

Aims To describe the bird guild and its behaviour visiting the century plant Agave americana in an insular environment and to determine which factors are affecting visitation rates.

Methods We noted number and species of birds visiting inflorescences on Tenerife, Canary Islands. We used multimodel inference of generalized linear models to analyse the factors affecting the number of visits and the visitor species richness.

Results Eighty-one per cent of inflorescences were visited by eight native bird species. All species fed on nectar and only the Atlantic Canary fed also on pollen. Foraging behaviour varied among species. Visitation rate increased with density and diversity of birds and flower characteristics and decreased through the day. The number of species visiting the inflorescences increased with diversity and density of birds in the surroundings and decreased through the day.

Conclusion The native bird community uses the invasive century plant as a feeding resource at a higher rate than it uses endemic ornithophilous plants. This could have negative effects for the pollination of endemic plants, but positive effects for birds.  相似文献   

9.
CapsuleExtensive surveys highlighted the importance of weedy fodder brassicas, stubbles and open farmland landscapes to declining birds.

Aims To determine habitat associations of seed-eating passerines on Scottish farmland in winter, and recommend appropriate conservation measures.

Methods Transect surveys were carried out on farmland in 100 1-km squares, containing 2885 fields, across Scotland. Birds, crops, field boundary features and weeds were recorded on three visits. Bird–habitat associations were examined using logistic regression models.

Results Seed-eating passerines were highly concentrated: 100 fields (1.4% of the area surveyed) held half the total count. The highest field densities of birds were recorded in fodder brassica crops and stubbles, averaging 12 and 3.3 birds/ha respectively. In fodder crops, weedier fields held many more birds. Multiple regression analysis emphasized the importance of fodder crops, stubbles and farmyards and suggested that declining bird species preferred more open landscapes. Several bird species were associated with fields containing very weedy patches, and/or weeds of the family Chenopodiaceae. These features were commonest in fodder brassicas. Many of the crop types found to be important as bird habitats in winter have declined in area in Scotland; the availability of seed food in such habitats may also have diminished. Such changes may partly explain recent population declines.

Conclusions Agri-environment measures for seed-eating passerines should support the widespread provision of small areas of seed-rich wintering habitats, such as weedy fodder brassicas and stubbles, especially in open (0–10% woodland and scrub) landscapes in areas with mild winters.  相似文献   

10.
This is the first report of the avian assemblage in the study area of Dutse, Nigeria. In addition to recording bird species, the effects of season, dominant vegetation structure, locality and anthropogenic activities on bird abundance, species richness and diversity were investigated. Using the point transect method, 264 points on 48 km of transect were used to count birds between 06:30 and 11:00 from August 2015 to February 2016. A total of 122 bird species of 41 families were recorded. Highest bird species richness was recorded in Warwade, highest abundance in Model, and highest diversity in Malamawa. The dry season and woodland habitat showed higher bird species richness, abundance and diversity than the wet season and shrubland habitat. Tree density was more important in increasing bird abundance than shrub density. Small-scale anthropogenic activities and habitat modification, such as farming, grazing, wood removal and human interference did not appear to have impacted the birds; however, loss of high tree-density woodland habitats may pose a major threat to the bird community in Dutse. The presence of birds of concern in the area suggests the need for conservation efforts of avifauna and as well as the forested habitats in Dutse.  相似文献   

11.
A vegetation survey was carried out in a relatively intact Atlantic blanket bog in Southwest Ireland to study the vegetation patterns in relation to environmental variation, and to quantify the effect of artificial and natural borders on compositional variation. The data were analysed using canonical correspondence analysis. In terms of both vegetation and water chemistry, the study site can be categorized as typical of Atlantic blanket bogs in the maritime regions of North-western Europe. The distribution of plant species was explained mainly by depth of the water table. The distribution of bryophytes was secondarily explained by the pH of the bog water, while the distribution of vascular plants was secondarily explained by concentrations of ammonia. The vegetation distribution exhibited little variation between the central sector of the peatland and its disturbed edges (hill-grazing and restoration areas), but a substantial variation was observed between the area along a natural edge (stream) and the areas close to the other peatland borders or centre. Similarly, the internal variation within each sector (centre, hill-grazing edge and restoration area edge) was small, but substantial vegetation variation was observed within the area located along the stream. The area along the stream was associated with relatively deep water table, shallow peat depth, high water colour, pH and NH4 + concentrations, and low Cl concentrations in the bog water. Our results suggest the existence of strong centre-natural margin gradients, as in raised bogs, and indicate that human or animal disturbance do not give rise to the marked transition zones that often characterize natural margins of mire systems. This indicates that even small areas and remnants of Atlantic blanket bogs are worthy of conservation and that their conservation value would benefit from the inclusion of sectors close to the natural peatland borders, which would increase the plant biodiversity of the conserved area.  相似文献   

12.
Drainage and afforestation of peatlands cause extensive habitat degradation and species losses. Restoration supports peatland biodiversity by creating suitable habitat conditions, including stable high water tables. However, colonization by characteristic species can take decades or even fail. Peatland recovery is often monitored shortly after restoration, but initial trends may not continue, and results might differ among taxonomic groups. This study analyzes trends in plant, dragonfly, and butterfly diversity within 18 years after rewetting of montane peatlands in central Germany. We compared diversity and species composition of 19 restored sites with three drained peatlands and one near‐natural reference site. Restoration resulted in improved habitat conditions and benefited species diversity, but there were marked differences among taxonomic groups. Dragonflies rapidly colonized small water bodies but their diversity did not further increase in older restoration sites. Characteristic peatland vegetation recovered slowly, since it depended on a high water holding capacity that was only reached after peat started accumulating. Generally, plant diversity developed toward reference conditions albeit incompletely, even 18 years after restoration. Butterflies responded less to peatland restoration; generalists increased only temporarily and specialists could not establish. In conclusion, peatland restoration improves habitat conditions and biodiversity, while trajectories of recovery are nonlinear and incomplete after two decades. This highlights the need for long‐term monitoring and a strategic selection of indicator species for evaluation of restoration success.  相似文献   

13.
The present study deals with the species abundance, diversity and species richness of avian communities in the Bangalore University Campus (BUC), Bengaluru, India. One hundred and six species of birds belonging to 42 families under 68 genera were recorded. Shannon–Wiener’s and Fisher’s alpha diversities, species evenness, species richness of bird communities, number of bird species and percentage of population density of birds between various seasons in the BUC differed significantly between the study years. Of these bird species, the relative abundance (6.96 %) and species distribution ratio (0.070) of Psittacula krameri were highest, whereas relative abundance (0.04 %) and species distribution ratio (0.002) of Coracias benghalensis were lowest. The existing 32 species of flowering plants/trees belonging to 29 genera under 14 families in the campus are used for perching by birds. Moreover 29 species of flowering plants/trees belonging to 24 genera under 16 families depend on birds for pollination and/or seed dispersal. Occurrence of greater bird diversity and abundance of avian communities were recorded highest in the winter season in the BUC premises. In the different seasons, the BUC had varying community structure of birds between the study years. BUC suffers from numerous threats namely grass cutting, fire and grazing of domestic animals. Conservation methods needed for habitat management are restoration of vegetation and wetlands, and increase plant and tree diversity to protect the ecosystem of BUC habitat and to preserve its diversity of avifauna.  相似文献   

14.
《Bird Study》2012,59(3):317-328
ABSTRACT

Capsule: Breeding bird survey data were used to compare biodiversity at sites defined as High Nature Value farmland (HNVf) under two different mapping models.

Aims: To examine whether farmland classified as HNVf was important for bird diversity and conservation of priority bird species in Cyprus, through comparison of two different HNVf maps. The HNV concept aims to define biodiversity-rich farmland and facilitate its protection and management. Heterogeneous, low-intensity cropping and grazing systems are important areas for biodiversity conservation in Europe and for birds in particular, but are threatened by abandonment and agricultural intensification. We compared two HNVf mapping systems, a simpler model based on land cover data (CLC map) and a more complex Cyprus Environment Department model (ED map) including layers relating to agricultural intensity.

Methods: Line transect bird surveys were carried out to compare bird diversity, abundance of farmland bird species of conservation priority and also of the endemic Cyprus Warbler Sylvia melanothorax, at sites classified as HNV or not.

Results: A greater diversity of breeding birds was found in sites classified as HNVf under combined ED and CLC maps. However, for the set of 12 priority bird species, neither HNV mapping approach encompassed their overall abundance, but a combined CLC and ED model did predict higher abundances of the Cyprus Warbler. Vineyard sites were found to be associated with high overall breeding bird diversity, but with low abundance of priority bird species.

Conclusion: We identified weaknesses in both mapping systems, with the ED model failing to capture all HNV grazing land and the CLC model defining some intensive farming systems as HNV. We conclude that the overlap between the two models best captures HNVf, but layers encompassing grazing land and priority habitats need to be added to better define HNVf in Cyprus and facilitate its protection and management.  相似文献   

15.
The purpose of this study was to consider the relative importance of several habitat variables in explaining the patterns in the structure of macroinvertebrate assemblages in open-water habitats, in relatively intact bogs and fens, which should inform conservation strategies. It was hypothesised that variables relating to the size of the water body would differentiate the communities and that some species would be unique to certain conditions. The macroinvertebrate communities from pools >100 m2, 10.1–100 m2 and Sphagnum hollows were characterised using sweep sampling for eight intact peatland sites across four bog types, and related to habitat variables including pool size, Sphagnum cover and hydrochemistry. Results showed community composition and structure differed significantly between deep, permanent pools and shallow, drought-sensitive Sphagnum hollows, with larger invertebrates, such as Odonates and Dytiscinae, rarely found in the hollows. Sphagnum cover accounted for a substantial amount of the variation in community composition. An examination of life-history strategies found species dependent on predictable conditions for juvenile development to be more abundant in pools. In contrast, taxa that could delay juvenile development until conditions were favourable were more abundant in Sphagnum hollows. These results highlight the importance of habitat heterogeneity in maintaining macroinvertebrate diversity in peatlands.  相似文献   

16.
We compared the relative contribution of blackwater inundation forest (igapó) and unflooded (terra firme) forest for regional bird species diversity in the lower Rio Negro region. For analyses of habitat preference we used mist-net samples and an unpublished bird species check-list. The igapó forest had lower bird species diversity than the terra firme forest. However, some 14% of the forest bird species in the region are restricted to igapó forest. Species composition was found to be distinct between the understories of the two forest types. Common forest bird guilds in the Neotropics such as ant-following birds avoid igapó forest. The differential habitat selection among birds in the inundated and unflooded forest is likely to result from vegetation structure and biological interactions such as aggressive behaviour. Since the inundated forest has a typical biota, conservation efforts needs to be directed to protect these habitats. Unfortunately, inundation forests are threatened by several human actions, especially dam construction. The extent of protected areas in the Brazilian Amazon is insufficient for the adequate protection of the inundated habitats, because it includes only 3% of the total area.  相似文献   

17.
Capsule Habitat associations of breeding birds in a complex coastal environment are clear, interpretable and mostly consistent between years.

Aims To match archive territory mapping data with historical aerial photographs and develop data handling and analytical techniques for the study of bird–habitat relationships.

Methods Bird registrations were digitized from archive British Trust for Ornithology Common Birds Census maps and habitat characteristics from contemporaneous aerial photographs. The resulting maps were overlaid and ranks of habitat preference for 15 species calculated using compositional analysis. Similarity analysis identified species with consistent habitat profiles across years. Cluster analysis identified groups of species with similar patterns of habitat use.

Results A total of 5400 registrations of 15 species in 14 habitats were analysed. Of these, 13 species showed stable patterns of habitat association across survey years. Clear differences and similarities in habitat preferences among the species were identified. The results may be used to inform conservation and management programmes in this and similar environments.

Conclusions Extensive archives of bird survey data can be used to study bird–habitat relationships and to measure the effects of natural and anthropogenic environmental change if contemporaneous aerial photographs can be sourced.  相似文献   

18.

Aims

The cultivation of Sphagnum mosses in paludiculture has high potential for the use of formerly drained peatlands under wet conditions. The aim of this study was to evaluate the plant species composition and vegetation structure of Sphagnum cultivation sites in comparison with near-natural donor sites and rewetted sites without Sphagnum introduction.

Location

Central Europe, northwest Germany close to the Dutch–German border.

Methods

The treatments (rewetting with and without Sphagnum introduction) and a near-natural donor as a reference were each studied at three different sites. At each site, bryophyte and vascular plant species composition as well as parameters of vegetation structure were sampled in 40 randomly positioned plots of 25 cm × 25 cm.

Results

In addition to the highly frequent Sphagnum, several further plant species typical of bogs were introduced. At two cultivation sites, the species composition showed a high degree of similarity to the near-natural donor sites, whereas the third site was more similar to the rewetted sites without the introduction of Sphagnum biomass. Rewetted sites were species-poor in comparison with all other sites. Apart from a high cover of Sphagnum, the vegetation structure at the cultivation sites differed significantly from the near-natural donor sites.

Conclusions

Sphagnum cultivation sites can be used to grow donor material for peatland restoration and contribute to species conservation by providing substitute habitat for bog-typical and threatened plant species.  相似文献   

19.
Species traits explain variation in detectability of UK birds   总被引:1,自引:0,他引:1  
Capsule Heterogeneous detectability amongst species may impact multi-species bird surveys and if not accounted for, may bias community level conclusions. Estimates of detectability were produced for 195 UK bird species, and detectability was significantly affected by bird size, diet and habitat specialization.

Aims To estimate detectability and understand which species traits may impact detectability.

Methods We estimated the detectability of 195 species of birds in the UK using distance sampling methods and examined the average detectability of genetically related groups. We tested the significance of species traits in describing variation in detectability, whilst controlling for phylogenetic relationships.

Results Passeriformes had the lowest median detectability of 0.37 and Charadriiformes the highest median detectability of 0.65, of the seven largest orders considered. Species most associated with closed habitats such as woodland and urban areas had the lowest detectability. Smaller species had lower detectability than larger species.

Conclusion Heterogeneity in species detectability could lead to biased conclusions, particularly when calculating multi-species indices such as species richness or diversity. Accounting for detectability will be most important in studies that cover a wide range of habitat types or a diverse spread of taxa.  相似文献   

20.
Many of the world’s large river systems have been greatly altered in the past century due to river regulation, agriculture, and invasion of introduced Tamarix spp. (saltcedar, tamarisk). These riverine ecosystems are known to provide important habitat for avian communities, but information on responses of birds to differing levels of Tamarix is not known. Past research on birds along the Colorado River has shown that avian abundance in general is greater in native than in non‐native habitat. In this article, we address habitat restoration on the lower Colorado River by comparing abundance and diversity of avian communities at a matrix of different amounts of native and non‐native habitats at National Wildlife Refuges in Arizona. Two major patterns emerged from this study: (1) Not all bird species responded to Tamarix in a similar fashion, and for many bird species, abundance was highest at intermediate Tamarix levels (40–60%), suggesting a response threshold. (2) In Tamarix‐dominated habitats, the greatest increase in bird abundance occurred when small amounts of native vegetation were present as a component of that habitat. In fact, Tamarix was the best vegetation predictor of avian abundance when compared to vegetation density and canopy cover. Our results suggest that to positively benefit avian abundance and diversity, one cost‐effective way to rehabilitate larger monoculture Tamarix stands would be to add relatively low levels of native vegetation (~20–40%) within homogenous Tamarix habitat. In addition, this could be much more cost effective and feasible than attempting to replace all Tamarix with native vegetation.  相似文献   

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