首页 | 本学科首页   官方微博 | 高级检索  
相似文献
 共查询到20条相似文献,搜索用时 15 毫秒
1.
Helmeted Guineafowl, Numida meleagris, populations have declined significantly within the Midlands of KwaZulu-Natal since the early 1980s. Because guineafowl have been observed feeding on harvested soybean lands and because raw soybeans are known to contain anti-nutritional factors, research into the digestibility of raw soybeans was conducted to investigate possible localized factors in suppressing populations of these birds. A digestibility study was carried out on the apparent metabolizable energy (AME) and the amino acids of both raw and processed soybeans, as well as a number of other feed ingredients, using Helmeted Guineafowl and adult roosters, Gallus gallus, as a control. The results of the energy balance studies were similar for both the guineafowl and the roosters. Soybean, both raw and processed, was found to be comparable with the other feed ingredients in terms of the digestibility of gross energy, but the amino acid digestibility of raw soybeans was considerably lower than that of processed soybean oilcake meal. The availability of raw soybean may thus only be contributing to localized dietary constraints within guineafowl populations.  相似文献   

2.
Coastal Fynbos on the Agulhas Plain of the Western Cape, South Africa, has been transformed extensively by crop and pastoral agriculture. Many bird species, e.g. sunbirds, nightjars and mousebirds have consequently been affected negatively by the reduction of suitable habitat for daily requirements. However, populations of certain bird species, especially granivores and omnivores, such as sparrows, larks and pipits, as well as Egyptian Geese and Helmeted Guineafowl have proliferated on the Agulhas Plain. This study investigates the effects of agricultural development on overall bird diversity on the Agulhas Plain. In 1998, twice monthly transect counts at 13 farmland sites recorded 106 bird species. Fifteen species occurred at 75% or more of the sites. Highest avian diversity was recorded at the sites with a mixture of crops and Coastal Fynbos (Mixed regime). A small number of species, e.g. sunbirds, are reliant on the natural Coastal Fynbos for their survival. With the exception of the Mixed regime that gained 50 species, all the other agricultural regimes reflected a loss of diversity when compared with Fynbos. To provide more suitable habitat for a greater diversity of birds, mixed landscapes should be maintained, and further destruction of natural Fynbos habitat should be prevented.  相似文献   

3.
《Ostrich》2013,84(2):153-156
Field surveys were conducted in the Krugersdorp Game Reserve, Gauteng province, South Africa, during 1978–1981 to study the habitat preferences of Helmeted Guineafowl Numida meleagris. The study area was traversed with a vehicle in the late afternoons on a set route (12 km) and at least one observation was conducted each month during the three-year period. With the aid of binoculars all guineafowl that were sighted were counted and recorded on a map. The purposes were to (1) describe the habitat preferences of guineafowl and (2) to demonstrate that weeds attracted guineafowl during winter and can be retained in modified landscapes (e.g. farms) to provide important microhabitats. The highest mean monthly density across five habitat categories throughout the year was recorded in old vegetable gardens. The old vegetable gardens of c. 35 ha attracted more than 60% of the guineafowl population from April to October, which was mainly during winter when the birds scratched actively in weedy patches.  相似文献   

4.
J. D. Macdonald 《Ostrich》2013,84(4):195-196
This study investigates the possibility of hybridisation between introduced domestic Helmeted Guineafowl Numida meleagris, derived from the West African subspecies N. m. galeata, and South African guineafowl, N. m. coronata. There is putative morphological evidence of such hybridisation in wild populations and it is known that domestic guineafowl do not survive well in the wild. Molecular analysis of the control region of mtDNA confirmed the occurrence of the domestic guineafowl haplotype in individuals present in wild populations from KwaZulu-Natal, but not in birds from populations from the Free State. Thus, despite the absence of the availability of bi-parentally inherited nuclear DNA marker, the presence of the domestic haplotype in individuals of both wild and intermediate phenotype (between wild and domestic birds) suggests that there is hybridisation in the wild between domestic and wild guineafowl. To avoid potential negative affects associated with outbreeding depression, we argue for careful control of releases of domestic guineafowl into the wild. This study investigates the possibility of hybridisation between introduced domestic Helmeted Guineafowl Numida meleagris, derived from the West African subspecies N. m. galeata, and South African guineafowl, N. m. coronata. There is putative morphological evidence of such hybridisation in wild populations and it is known that domestic guineafowl do not survive well in the wild. Molecular analysis of the control region of mtDNA confirmed the occurrence of the domestic guineafowl haplotype in individuals present in wild populations from KwaZulu-Natal, but not in birds from populations from the Free State. Thus, despite the absence of the availability of bi-parentally inherited nuclear DNA marker, the presence of the domestic haplotype in individuals of both wild and intermediate phenotype (between wild and domestic birds) suggests that there is hybridisation in the wild between domestic and wild guineafowl. To avoid potential negative affects associated with outbreeding depression, we argue for careful control of releases of domestic guineafowl into the wild.  相似文献   

5.
This study describes the relationship between Helmeted Guineafowl Numida meleagris and invasive alien trees on livestock and maize farms south-east of Johannesburg, Gauteng province, South Africa. The dependence of the birds on alien trees affects strategies for the removal of these trees. During June to December 2014, Helmeted Guineafowl were recorded weekly on maps along a 42 km transect. Since Helmeted Guineafowl live in cohesive social groups of 15–20 birds, they roost communally in one or two trees during winter rather than spreading across an entire tree grove. The distribution of alien trees across the landscape in patches has enabled Helmeted Guineafowl flocks to reach new feeding patches near to roosting trees, as old feeding patches are depleted. One Helmeted Guineafowl flock of 15–20 birds requires ~0.09 ha covered with mature alien trees for roosting. Suggestions are presented relating to the reduction of alien trees in compliance with the Conservation of Agricultural Resources Act 43 of 1983 and conservation of Helmeted Guineafowl.  相似文献   

6.
Landscape pattern metrics are widely used for predicting habitat and species diversity. However, the relationship between landscape pattern and species diversity is typically measured at a single spatial scale, even though both landscape pattern, and species occurrence and community composition are scale‐dependent. While the effects of scale on landscape pattern are well documented, the effects of scale on the relationships between spatial pattern and species richness and composition are not well known. Here, our main goal was to quantify the effects of cartographic scale (spatial resolution and extent) on the relationships between spatial pattern and avian richness and community structure in a mosaic of grassland, woodland, and savanna in central Wisconsin. Our secondary goal was to evaluate the effectiveness of a newly developed tool for spatial pattern analysis, multiscale contextual spatial pattern analysis (MCSPA), compared to existing landscape metrics. Landscape metrics and avian species richness had quadratic, exponential, or logarithmic relationships, and these patterns were generally consistent across two spatial resolutions and six spatial extents. However, the magnitude of the relationships was affected by both resolution and extent. At the finer resolution (10‐m), edge density was consistently the best predictor of species richness, followed by an MCSPA metric that measures the standard deviation of woody cover across extents. At the coarser resolution (30‐m), NDVI was the best predictor of species richness by far, regardless of spatial extent. Another MCSPA metric that denotes the average woody cover across extents, together with percent of woody cover, were always the best predictors of variation in avian community structure. Spatial resolution and extent had varying effects on the relationships between spatial pattern and avian community structure. We therefore conclude that cartographic scale not only affects measures of landscape pattern per se, but also the relationships among spatial pattern, species richness, and community structure, often in complex ways, which reduces the efficacy of landscape metrics for predicting the richness and diversity of organisms.  相似文献   

7.
We studied the relationship between genetic diversity of the subterranean Gansu zokor Myospalax cansus and habitat variability in the Loess Plateau, Qinghai Province, China. We used a combination of geographic information systems and molecular techniques to assess the impact of habitat composition and human activities on the genetic diversity of zokor populations in this semi-natural landscape. Although they occurred relatively infrequently in the landscape, woodland and high-coverage grassland habitats were the main positive contributors to the genetic diversity of zokor populations. Rural residential land, plain agricultural land and low-coverage grassland had a negative effect on genetic diversity. Hilly agricultural land and middle-coverage grassland had little impact on zokor genetic diversity. There were also interactions between some habitat types, that is, habitat types with relatively better quality together promoted conservation of genetic diversity, while the interaction between (among) bad habitat types made situations worse. Finally, habitat diversity, measured as patch richness and Shannon's diversity index, was positively correlated with the genetic diversity. These results demonstrated that: (1) different habitat types had different effects on the genetic diversity of zokor populations and (2) habitat quality and habitat heterogeneity were important in maintaining genetic diversity. Habitat composition was closely related to land use thus emphasizing the importance of human activities on the genetic diversity of subterranean rodent populations in this semi-natural landscape. Although the Gansu zokor was considered to be a pest species in the Loess Plateau, our study provides insights for the management and conservation of other subterranean rodent species.  相似文献   

8.
The objective of this study was to determine the relative population densities and habitat utilization of gamebird species in relation to plant communities, the amount of ecotone, and vegetation structure. The distribution of five terrestrial gamebird populations was monitored for 12 months in the Nyslvley Nature Reserve, South Africa. Only three species, Swainson's francolin (40.44% of the total gamebird population), crested francolin (10.41%) and guineafowl (43.94%), were found in significant numbers. Group sizes of these gamebird populations were typical for the species. The high amount of edge or ecotone (total amount of edge (DI) = 0.26), the short (9.36 cm) and evenly structured grass layer (mean Foliage Height Diversity (FHD) = 0.38), and a mosaic of open areas and termitaria thickets rendered the Sporobolus ioclados–Acacia tortilis Savanna suitable for gamebirds. The adjacent seasonally inundated floodplain was also utilized to some extent, mainly by Swainson's francolin. It appears that visibility is more important for gamebirds than a high diversity in grass structure. Also, a mosaic of feeding areas and cover makes an area suitable for terrestrial gamebirds. Of the gamebird species found in the reserve, only the Swainson's francolin, crested francolin and guineafowl populations had the potential to be harvested.  相似文献   

9.
Urban expansion threatens global biodiversity through the destruction of natural and semi-natural habitats and increased levels of disturbance. Whilst woodlands in urban areas may reduce the impact of urbanisation on biodiversity, they are often subject to under or over-management and consist of small, fragmented patches which may be isolated. Effective management strategies for urban woodland require an understanding of the ecology and habitat requirements of all relevant taxa. Yet, little is known of how invertebrate, and in particular moth, assemblages utilise urban woodland despite being commonly found within the urban landscape. Here we show that the abundance, species richness, and species diversity of moth assemblages found within urban woodlands are determined by woodland vegetation character, patch configuration and the surrounding landscape. In general, mature broadleaved woodlands supported the highest abundance and diversity of moths. Large compact woodlands with proportionally less edge exposed to the surrounding matrix were associated with higher moth abundance than small complex woodlands. Woodland vegetation characteristics were more important than the surrounding landscape, suggesting that management at a local scale to ensure provision of good quality habitat may be relatively more important for moth populations than improving habitat connectivity across the urban matrix. Our results show that the planting of broadleaved woodlands, retaining mature trees and minimising woodland fragmentation will be beneficial for moth assemblages.  相似文献   

10.
Federal mandates to increase biofuel production in North America will require large new tracts of land with potential to negatively impact biodiversity, yet empirical information to guide implementation is limited. Because the temperate grassland biome will be a production hotspot for many candidate feedstocks, production is likely to impact grassland birds, a group of major conservation concern. We employed a multiscaled approach to investigate the relative importance of arthropod food availability, microhabitat structure, patch size and landscape‐scale habitat structure and composition as factors shaping avian richness and abundance in fields of one contemporary (corn) and two candidate cellulosic biomass feedstocks (switchgrass and mixed‐grass prairie) not currently managed as crops. Bird species richness and species density increased with patch size in prairie and switchgrass, but not in corn, and was lower in landscapes with higher forest cover. Perennial plantings supported greater diversity and biomass of arthropods, an important food for land birds, but neither metric was important in explaining variation in the avian community. Avian richness was higher in perennial plantings with greater forb content and a more diverse vegetation structure. Maximum bird species richness was commonly found in fields of intermediate vegetation density and grassland specialists were more likely to occur in prairies. Our results suggest that, in contrast to corn, perennial biomass feedstocks have potential to provide benefits to grassland bird populations if they are cultivated in large patches within relatively unforested landscapes. Ultimately, genetic improvement of feedstock genets and crop management techniques that attempt to maximize biomass production and simplify crop vegetation structure will be likely to reduce the value of perennial biomass plantings to grassland bird populations.  相似文献   

11.
The South African grassland biome is one of the most threatened biomes in South Africa. Approximately 45% of the grassland biome area is transformed, degraded or severely invaded by alien plants and the remaining natural areas are highly fragmented. In this fragmented landscape, the connectivity between habitat patches is very important to maintain viable populations. In this study we aimed to quantify connectivity of the grassland biome in Mpumalanga using graph theory in order to identify conservation priorities and to direct conservation efforts. Graph theory‐based connectivity indices have the ability to combine spatially explicit habitat data with species specific dispersal data and can quantify structural and functional connectivity over large landscapes. We used these indices to quantify the overall connectivity of the study area, to determine the influence of abandoned croplands on overall connectivity, and to identify the habitat patches and vegetation types most in need of maintaining overall connectivity. Natural areas were identified using 2008 land cover data for Mpumalanga. Connectivity within the grassland biome of Mpumalanga was analysed for grassland species with dispersal distances ranging from 50 to 1000 m. The grassland habitat patches were mostly well connected, with 99.6% of the total habitat area connected in a single component at a threshold distance of 1000 m. The inclusion of abandoned croplands resulted in a 33% increase in connectivity at a threshold distance of 500 m. The habitat patches most important for maintaining overall connectivity were the large patches of continuous habitat in the upper and lower centres of the study area and the most important vegetation types were the Wakkerstroom Montane Grassland and the Eastern Temperate Freshwater Wetlands. These results can be used to inform management decisions and reserve design to improve and maintain connectivity in this biome.  相似文献   

12.
Eastern collared lizards of the Ozarks live in glades—open, rocky habitats embedded in a woodland matrix. Past fire suppression had made the woodlands a barrier to dispersal, leading to habitat destruction, fragmentation and local extinction. Reintroduced populations of lizards were subjected to 10 years of habitat fragmentation under continued fire suppression followed by twelve years of landscape restoration with prescribed burns. Prior to prescribed burning, genetic diversity decreased within glades and differentiation increased among glades. With woodland burning, genetic diversity within glades first decreased during an expanding colonization phase, but then increased as a dynamically stable metapopulation was established. Population differentiation among glades also stabilized in the metapopulation under weak isolation‐by‐distance. This study is one of the first to examine the genetic changes in a species of conservation concern throughout all the stages of decline and recovery and shows the importance of landscape‐level restoration for maintaining the genetic integrity of populations. This study also demonstrates how mark–recapture and genetic data together can yield detailed insight into metapopulation dynamics that would be impossible from just one type of data alone.  相似文献   

13.
The Palearctic forest-steppe biome is a narrow vegetation zone between the temperate forest and steppe biomes, which provides important habitats for many endangered species and represents an important hotspot of biodiversity. Although the number of studies on forest–grassland mosaics is increasing, information currently available about the general compositional and structural patterns of Eurasian forest-steppes is scarce. Our study aimed to compare the habitat structure, species composition and diversity patterns of two distant sandy forest-steppes of Eurasia. We compared 72 relevés made in the main habitat components (forest, forest edge and grassland) of sandy forest-steppes in three Hungarian and three Kazakh sites. The size of the plots was 25 m2. Species number, Shannon diversity and species evenness values were calculated for each plot. Fidelity calculations and linear mixed effects models were used for the analyses. We found that the vegetation and diversity patterns of the two forest-steppes are similar and their components play important roles in maintaining landscape-scale diversity. Despite the higher species richness in Hungary, Shannon diversity was higher in Kazakhstan. The deciduous forest edges of both areas had significantly higher species richness than the neighbouring habitats (forests and grasslands); therefore they can be considered local biodiversity hotspots. Due to the special characteristics of this vegetation complex, we emphasize the high conservation value of all landscape components as a coherent system throughout the entire range of the Eurasian forest-steppe biome.  相似文献   

14.
Aim To examine biogeographical affiliations, habitat‐associated heterogeneity and endemism of avian assemblages in sand forest patches and the savanna‐like mixed woodland matrix. Location Two reserves in the Maputaland Centre of Endemism (MC) on the southern Mozambique Coastal Plain of northern KwaZulu‐Natal, South Africa. Methods Replicated surveys were undertaken in each of the two habitat types in each reserve, providing species abundance data over a full year. Vegetation structure at each of the survey sites was also quantified. Differences between the bird assemblages and the extent to which vegetation structure explained these differences were assessed using multi‐variate techniques. Biogeographical comparisons were based on species presence/absence data and clustering techniques. Results Bird assemblages differed significantly between habitats both within a given reserve and between reserves, and also between reserves for a given habitat. Differences in vegetation structure contributed substantially to differences between the avian assemblages. Of the four species endemic to the MC, three (Neergaard’s sunbird, Rudd’s apalis, and Woodward’s batis) were consistently present in sand forest. The fourth (pink‐throated twinspot) preferred mixed woodland. None of these endemic species was classed as rare. In the biogeographical analysis, both the sand forest and the mixed woodland bird assemblages were most similar to bird assemblages found in the forest biome or the Afromontane forest biome, depending on the biome classification used. Main conclusions The close affinities of sand forest and mixed woodland assemblages to those of the forest biome are most likely due to similarities in vegetation structure of these forests. Bird assemblages differ between the sand forest and mixed woodland habitats both within a given reserve and between reserves, and also between reserves for a given habitat. These differences extend to species endemic to the MC. Thus, conservation of sand forest habitat in a variety of areas is necessary to ensure the long‐term persistence of the biota.  相似文献   

15.
Dispersal limitation between habitat fragments is a known driver of landscape-scale biodiversity loss. In Europe, agricultural intensification during the twentieth century resulted in losses of both grassland habitat and traditional grassland seed dispersal vectors such as livestock. During the same period, populations of large wild herbivores have increased in the landscape. Usually studied in woodland ecosystems, these animals are found to disperse seeds from grasslands and other open habitats. We studied endozoochorous seed dispersal by roe deer (Capreolus capreolus) in fragmented grasslands and grassland remnants, comparing dispersed subcommunities of plant species to those in the established vegetation and the seed bank. A total of 652 seedlings of 67 species emerged from 219 samples of roe deer dung. This included many grassland species, and several local grassland specialists. Dispersal had potentially different effects on diversity at different spatial scales. Almost all sites received seeds of species not observed in the vegetation or seed bank at that site, suggesting that local diversity might not be dispersal limited. This pattern was less evident at the landscape scale, where fewer new species were introduced. Nonetheless, long-distance dispersal by large wild herbivores might still provide connectivity between fragmented habitats within a landscape in the areas in which they are active. Finally, as only a subset of the available species were found to disperse in space as well as time, the danger of future biodiversity loss might still exist in many isolated grassland habitats.  相似文献   

16.
This study investigates the importance of spatial landscape characteristics and habitat management on the condition of calcareous grassland in the North Down Natural Area, Kent UK. We used a digitised map of the study area containing shapefiles of all the habitats including 82 patches of calcareous grassland together with management information for each patch and data on the presence and abundance of a range of calcareous grassland indicator plant species. We defined habitat condition by presence of indicator species and used classification trees to generate models with rules for predicting habitat condition from the landscape spatial characteristics and management information. We also applied the same method to investigate the factors affecting presence or diversity of three ecological groups of positive indicator species and dominance of a negative indicator species. All the models except one showed good classification accuracy and high kappa statistic. Favourable habitat condition was predicted by presence of different types of grazing management, presence of woodland around patches of calcareous grassland and shape complexity. These results indicate that calcareous grassland in favourable condition is management-dependent but also located in less intensively managed landscapes. Unfavourable habitat condition was predicted by threat factors such as lack of management and high incidence of arable or improved grassland around patches of calcareous grassland, indicating nutrient enrichment and habitat degradation. Some of these factors also predicted high diversity of the different ecological species groups. The value of this method for predicting habitat condition and species diversity from baseline ecological data for conservation monitoring at the landscape level is emphasised.  相似文献   

17.
Many passerine bird populations, particularly those that have open‐cup nests, are in decline in agricultural landscapes. Current theory suggests that an increase in habitat generalist predators in response to landscape change is partially responsible for these declines. However, empirical tests have failed to reach a consensus on how and through what mechanisms landscape change affects nest predation. We tested one hypothesis, the Additive Predation Model, with an artificial nest experiment in fragmented landscapes in southern Queensland, Australia. We employed structural equation modelling of the influence of the relative density of woodland and habitat generalist predators and landscape features at the nest, site, patch and landscape scales on the probability of nest predation. We found little support for the Additive Predation Model, with no significant influence of the density of woodland predators on the probability of nest predation, although landscape features at different spatial scales were important. Within woodlands fragmented by agriculture in eastern Australia, the presence of noisy miner colonies appears to influence ecological processes important for nest predation such that the Additive Predation Model does not hold. In the absence of colonies of the aggressive native bird, the noisy miner, the influence of woodland predators on the risk of artificial nest predation was low compared with that of habitat generalist predators. Outside noisy miner colonies, we found significant edge effects with greater predation rates for artificial nests within woodland patches located closer to the agricultural matrix. Furthermore, the density of habitat generalist predators increased with the extent of irrigated land‐use, suggesting that in the absence of noisy miner colonies, nest predation increases with land‐use intensity at the landscape scale.  相似文献   

18.
Landscape heterogeneity affects the spatial distribution of species. This makes it an important consideration for conservation planning, particularly when designing sustainable production landscapes. We determine whether conserving landscape elements within a transformed landscape is adequate for conserving dung beetle biodiversity. Dung beetles are excellent indicators for landscape biodiversity studies as they are ecologically sensitive. Here we measure dung beetle alpha-diversity, as well as beta-diversity within landscape elements and across different landscape elements. In doing so, we assess the value of landscape elements, as well as variation within landscape elements, in determining the spatial distribution of dung beetles across a production landscape. The study was conducted in the commercial timber production area of the KwaZulu-Natal Midlands, South Africa. In this system, the different landscape elements are a mosaic of natural indigenous forests, grasslands and alien pine plantation blocks. Our results show that the only response for dung beetle alpha-diversity was higher species richness in grasslands and pine blocks compared to natural forests. The highest beta-diversity for a landscape element was the grassland, for elevational category was low elevational areas and grassland type was the Midlands Mistbelt Grassland. The compositional diversity (beta-diversity between elements) was significantly different for all pairwise variations between landscape elements, the elevational categories and grassland types. Natural forests embedded in the two different grassland types had greater differences in compositional diversity than those embedded in natural (grassland) or transformed (pine blocks) matrices. This highlights the need to conserve a range of similar remnant patches of natural vegetation regionally, in addition to conserving broad landscape elements (i.e. grasslands or natural forests) as conservation targets. Furthermore, our results are encouraging for the potential benefits from the ecosystem service provided by dung beetles across the whole landscape, even in the transformed elements.  相似文献   

19.
Avian community composition of kopjes in a heterogeneous landscape   总被引:1,自引:0,他引:1  
Trager M  Mistry S 《Oecologia》2003,135(3):458-468
We examined avian communities of kopjes (naturally occurring insular rock outcrops) in grassland and thorn tree woodland habitats in the Seronera region of Serengeti National Park, northwestern Tanzania. Although kopjes cover a small proportion of the Park's area, they provide resources that are uncommon in the Serengeti landscape and are known to host diverse, yet poorly documented, biotic communities. The primary objectives of this study were (1) to compare avian communities of kopjes with those of their surrounding habitat matrixes; (2) to compare the avian communities among kopjes; and (3) to determine the effects of kopje characteristics (e.g., size, vegetation cover, level of human disturbance and matrix type) on avian diversity and community composition. The avian communities of kopjes differed significantly from those of the matrixes in species composition and guild characteristics. Rare species, frugivorous species and nectarivorous species were more abundant on kopjes, whereas there were more ground-feeding species in matrix sites. Species richness was positively correlated with the area of kopjes covered by tall vegetation (5+ m), but neither total habitat area nor total vegetation cover significantly affected avian diversity. The surrounding habitat type, the fruiting phenology of Ficus and Commiphora trees and the level of human disturbance also influenced the presence and abundance of individual species and accounted for differences in community composition among kopjes. Our results show that kopjes support unique avian assemblages comprising many species that are otherwise rare in Serengeti, and consequently that kopjes may be local hotspots of avian diversity in the region.  相似文献   

20.
Diversity of ground beetle (Coleoptera: Carabidae) assemblages and sub‐assemblages was compared between reafforested woodland, grassland, and intensively cultivated fields at Chongli County in Northern China. An array of eight pitfall traps per plot was used to sample the beetles on four replicate plots for each habitat. Replanted conifer woodland and semi‐natural grassland harbored very similar beetle assemblages. These had significantly lower rarefied species numbers than the distinctly different assemblages recorded in cultivated fields, with differences in alpha diversity being less pronounced for large and predatory species. Carabid activity‐density levels were higher in both woodland and grassland than in fields, with this trend being most pronounced for predatory and large species. To conserve high levels of gamma diversity, it is important to maintain a mosaic of agricultural areas and semi‐natural habitats. The latter also form a potential source for predatory species important in pest control. It appears that woodland‐specific species are rare in the study area, or they have not been able to reach and colonize the newly established woodland sites. It can also be concluded that morphological and ecological traits allow important insights into underlying ecological principles of overall diversity patterns.  相似文献   

设为首页 | 免责声明 | 关于勤云 | 加入收藏

Copyright©北京勤云科技发展有限公司  京ICP备09084417号