Bird Biodiversity Research Articles

Crop patterns and habitat preferences of the grey partridge farmland bird

Agricultural changes such as intensification and specialization are thought to be the major source of the severe decline of farmland bird populations observed on large spatial scales and over long time spans in Europe. We studied farmers' practices at a local level on 22 farms from the Beauce area, France, with regard to habitat preferences of grey partridge, Perdix perdix L. We focused on the study of vegetation cover because it influences grey partridge's reproduction and survival. The results revealed a high diversity of vegetation cover over the municipal territory. This high diversity can be explained by (1) the difference in the crops cultivated by the farmers, only wheat being cultivated by all the farmers; (2) the diversity of elementary crop sequences implemented, as many as 51 having been identified; and (3) the field size, which varies from 0.5 ha to 57 ha, with 54% of fields smaller than 10 ha. Altogether, this potentially creates six different habitat types, 32% of the arable land surveyed being a likely suitable habitat for the grey partridge. We found that irrigation was the main driving factor of vegetation cover diversity. Indeed irrigation controls the farms' crop acreage, the crop sequences and their spatial pattern and field size. Nonetheless, irrigation practices show both positive, e.g. crop diversity, and negative aspects, e.g. large fields and clutch failure, for ground-nesting birds such as the grey partridge. Based on these results, a GIS modeling of the municipal landscape related to grey partridge's habitat requirements is possible and would allow a deeper analysis of the impact of crop diversity on grey partridge populations. cash crop ecosystems / crop sequences / farmland bird biodiversity / grey partridge / technical farm management

Avian diversity in a Kenyan agroecosystem: effects of habitat structure and proximity to forest

Tropical agroecosystems cover an increasingly large proportion of the Earth’s terrestrial surface. Yet, relatively little is known about the factors that influence their avifauna, especially in areas of high human population density. The potential of tropical farmland for sustaining bird biodiversity, including forest birds, can be influenced by habitat structure and the distance from the nearest forest. We investigated the effect of these two factors on the bird community in the farmland near Kakamega Forest, Kenya. Using point counts, we assessed the number of bird species and individuals on 56 study plots in distances up to about 2,100 m from the forest. We observed a total of 96 bird species in the farmland, 22 of which were forest, 58 shrub-land, and 16 open-country species. High vertical vegetation heterogeneity and a large number of woody plant individuals were related to high species richness of forest and shrub-land birds, whereas open-country birds avoided such areas. The species richness and total number of forest birds declined with increasing distance to the forest. A comparison with the bird community within Kakamega Forest indicated that only a fraction of the forest species could be sustained in the farmland. This suggests that agroecosystems with a diverse habitat structure can support a high diversity of birds, but have only a limited capacity to compensate for forest loss.

Breeding birds in hemiboreal clear-cuts: tree-retention effects in relation to site type

Summary The variability of natural disturbance regimes implies that retention cutting, aimed at emulating natural disturbances to support biodiversity, should be forest-type specifi c. We explored in four site types (ranging from dry nutrient-poor to wet nutrient-rich) in Estonia how the retention of live and dead trees affects post-cut abundance and species richness of birds. The whole bird communities and harvest-sensitive species groups responded differently: while the total abundance and relative species richness of birds increased along with the abundance of dead trees, the species of national conservation concern occurred more frequently at higher densities of live trees. Hence, although the species of conservation concern and hole-nesters preferred the cuts having the generally densest and most species-rich avian communities, this co-variation was obviously insuffi cient for using the total community characteristics (particularly density) as indicators of forestry impacts on bird biodiversity. In contrast to expectations, tree retention always infl uenced birds independently of forest type. This may be related to the particular study system (notably low retention levels) but future studies should nevertheless explicitly address to what extent forest species are adapted to natural disturbances, and in which cases that knowledge can be used for forestry planning.

Study on Avi-fauna Diversity in Mangrove Area in Aceh Besar Post Tsunami 2004

The research was conducted after tsunami destroyed mangrove in Aceh Besar coastal area, whichserves as waterfowl habitat. This study was aimed to find out bird diversity and abundant after tsunamidisaster. The study was conducted in Kecamatan Mesjid Raya, Aceh Besar, focusing on bird biodiversityand its number based on habitat type, using count dot survey technique. The study revealed that as manyas eight waterfowl species from four families were found. The variety of bird species in the researchlocation was low, ie; 1.2196 for fish pond, 1.7257 for muddy land, and 1.2528 for vegetation area. The lowlevel of biodiversity indicated fragmented habitat in the mangrove area.Keywords: mangrove conservation, bird biodiversity index, bird conservation

Crops, trees, and birds: Biodiversity change under agricultural intensification in Uganda's farmed landscapes

Geografisk Tidsskrift, Danish Journal of Geography 106(2): 115–130, 2006 This paper examines the relationship between the intensity of agricultural land use and the abundance and richness of trees and birds in a humid tropical developing region where natural vegetation is being rapidly converted into farmland under market and population pressures. We analysed survey data on land use, birds and woody plants collected in 14 study sites situated within smallholder cropland and commercial plantations in southern Uganda. Commercial plantations had very few trees and only 10% of the original bird species. Land use intensification in smallholder systems also showed losses in bird abundance and species richness, but not nearly as much as in plantations. In both systems the impact of intensification was much bigger on the specialised and threatened birds compared to the less specialised species. This argues strongly for ‘species-sensitive’ conservation policies combining protected areas with land use regulation in areas undergoing intensification. We also found a much higher loss in bird biodiversity during the first phases of land use intensification (when larger tracts of forest are cleared) than in later phases characterised by clearing of smaller patches of vegetation and improved management of farm trees. This suggests high pay-offs to geographical targeting of conservation efforts in farmed landscapes.

Bird–Vegetation Relationships in Southeastern British Columbia

To produce better habitat models, we analyzed a 1977 breeding bird data set with recently developed techniques. Our generalized linear models for specific bird species produced precise descriptions of bird–vegetation relationships, using visually obvious habitat features (e.g., grass, broad-leaved shrubs, and conifers of differing heights). This was, in general, confirmed by canonical correspondence analysis, which related the entire bird community to the vegetation across the successional stages. Nevertheless, our analyses produced some results that contradicted our expectations; ground-nesting species negatively associated with bunch grasses (species that grow in clumps within the Agropyron, Festuca, and Stipa genera), and cavity-nesting species negatively associated with stumps and snags. We speculate that those contrary relationships resulted from nest sites not being a limiting resource. We conclude that visually obvious vegetation features are sufficient to describe most breeding bird–habitat relationships. Further, appropriate landscape management for bird biodiversity requires that all successional stages are present.

Conflicting demands on wetland ecosystem services: nutrient retention, biodiversity or both?

Summary1. Wetland ecosystems may, besides having considerable economical value, increase landscape biodiversity and function as traps for nutrients from land to freshwater‐ and marine systems. As a result of these features, wetlands are nowadays often protected and restored, and many countries have even initiated wetland construction programmes.2. In the present study, we aim at increasing the knowledge on how to improve the design of a wetland with respect to both biodiversity and nutrient retention, by analysing physical, chemical and biological features of a large set of constructed wetlands.3. Our results show that a combination of the wetland features, namely shallow depth, large surface area and high shoreline complexity are likely to provide a high biodiversity of birds, benthic invertebrates and macrophytes and to have high nitrogen retention, whereas a small, deep wetland is likely to be more efficient in phosphorus retention, but less valuable in terms of biodiversity.4. Hence, among the features used to design new wetlands, area, depth and shoreline complexity have fundamental, and sometimes conflicting, effects on nutrient retention and biodiversity. This means that there are, within limits, possibilities to direct the ecosystem function of a specific wetland in desired directions.

Assessing ecological resources for remediation and future land uses on contaminated lands.

Increasingly, the public and governmental agencies are concerned about remediating and reclaiming contaminated sites. Understanding the ecological resources on-site and valuing those resources in terms of future uses is important for determining suitable future land uses. In this article, we suggest the major categories of natural resource information required by managers, policy makers, and the general public for making initial future land-use determinations. We then use a dataset of 25 Department of Energy (DOE) sites slated for remediation to explore whether such data are readily available and whether the data can be used to assess natural resource value. Although information is available for almost all sites on federally endangered and threatened species, this information is less available for state-listed species. Biodiversity information is available only for some sites for birds ( N = 17), mammals ( N = 15), reptiles ( N = 14), amphibians ( N = 13), and plants ( N = 11) and is almost nonexistent for invertebrates ( N = 2). Some information is available for invasive species ( N = 9). The number of available habitats is directly related to total acres and nonindustrial acres. Biodiversity of birds, mammals, and reptiles (but not amphibians) is directly related to both total acres and total nonindustrial acres of sites. These data suggest that even over a wide geographical area (from eastern to western United States), biodiversity relates to habitat size and number of habitats available. This information will be useful not only to DOE managers but also to natural resource trustees, ecologists, state and federal regulators, and the general public in the discourse over future uses of these lands.

Are Pinus halepensis plantations useful as a restoration tool in semiarid Mediterranean areas?

In the semiarid areas of the Mediterranean basin, restoration activities during the XXth century have mainly relied on extensive plantations of Pinus halepensis, which now cover thousands of hectares. Here we review studies that have evaluated the effects of these plantations on soils, vegetation, faunal communities, and forest fires. The effects of P. halepensis plantations on soil properties are highly dependent on the planting technique employed. Plantations frequently show enhanced runoff and soil losses when compared to natural shrublands, as well as limited improvement in most physio-chemical properties, which rarely reach the values shown by natural shrublands even 40 years after planting. The increase in tree cover resulting from the introduction of P. halepensis is commonly accompanied by an increase in water use, which may have relevant hydrological consequences at the catchment scale. Most studies performed so far have shown an overall negative effect of P. halepensis plantations on spontaneous vegetation. In these plantations, vegetation is dominated by early-successional species, and the establishment of late-successional sprouting shrubs—even after several decades—has been rarely reported. The effects of P. halepensis plantations on faunal communities may vary depending on the animal group considered. Available studies suggest that P. halepensis plantations can reduce bird biodiversity and promote pest outbreaks. Our review contributes to the debate on the suitability of mono-specific extensive P. halepensis plantations, and suggests that afforestation programmes should be revised.

Importance of gravel pits for the conservation of waterbirds in the Garonne river floodplain (southwest France)

The loss of natural wetlands throughout the World has made created habitats such as gravel pits, reservoirs or rice fields potentially important for waterbird conservation. In southwest France, the increasing abundance of gravel pits has allowed several bird species to colonize the region. The avian community was studied from 1996 to 1998 in six gravel pits in the Garonne floodplain. A total of 39 species of waterbirds were recorded, with higher abundance during the winter and post-breeding periods. We analyzed habitat use to identify key environmental factors determining the temporal and spatial distribution of the avian community. The presence of submerged macrophytes was found to be the most important factor influencing the distribution of waterbirds. The presence of paths in the vicinity of the areas reduced both the total number of birds and species richness owing to human disturbance. Gravel pits have an increasingly important role in the conservation of bird biodiversity. By controlling disturbance and management of vegetation, managers can enhance this role.

Conserving Bird Biodiversity: General Principles and their Application

Conserving Bird Biodiversity: General Principles and their Application

Mapping and monitoring of coastal wetlands of Çukurova Delta in the Eastern Mediterranean region

The aim of this research was to link vegetation characteristics, such as spatial and temporal distribution, and environmental variables, with land cover information derived from remotely sensed satellite images of the Eastern Mediterranean coastal wetlands of Turkey. The research method was based on (i) recording land cover characteristics by means of a vegetation indicator, and (ii) classifying and mapping coastal wetlands utilizing a Landsat Thematic Mapper (TM) image of Cukurova Deltas in Turkey. Vegetation characteristics of various habitats, such as sand dunes, salt marshes, salty plains and afforestation areas, were identified by field surveys. A Landsat TM image of 4 July 1993 was pre-processed and then classified using the Maximum Likelihood (ML) algorithm and Artificial Neural Networks (ANN). As a result of this supervised classification, the land cover types were classified with a largest accuracy of 90.2% by ANN. The classified satellite sensor imagery was linked to vegetation and bird census data, which were available through literature in a Geographical Information System (GIS) environment to determine the spatial distribution of plant and bird biodiversity in this coastal wetland. The resulting data provide an important baseline for further investigations such as monitoring, change detections and designing conservation policies in this coastal ecosystem.

Conserving Bird Biodiversity: General Principles and their Application

Conserving Bird Biodiversity: General Principles and their Application

Conserving Bird Biodiversity: General Principles and Their Application

Preface 1. Biodiversity - evolution, species, genes Michael W. Bruford 2. Why conserve bird diversity? Colin Bibby 3. Mapping and monitoring bird populations: their conservation uses Les Underhill and David Gibbons 4. Priority setting in species conservation Georgina M. Mace and Nigel J. Collar 5. Setting sites for protection Andrew Balmford 6. Critically endangered bird populations and their management, Ben D. Bell and Don V. Merton 7. Diagnosing causes of population declines and selecting remedial actions Rhys E. Green 8. Outside the reserve: pandemic threats to bird biodiversity Deborah J. Pain and Paul F. Donald 9. Predicting the impact of environmental change Ken Norris and Richard Stillman 10. Fragmentation, habitat loss and landscape management Paul Opdam and John A. Wiens 11. The interface between research, education and training Leon Bennun 12. Conservation policies and programs affecting birds Gerard C. Boere and Clayton D. A. Rubec References Index.

Effects of floristics, physiognomy and non‐native vegetation on riparian bird communities in a Mojave Desert watershed

Summary In the deserts of the south‐western United States of America, as in many ecoregions around the world, invasion of non‐native plants is modifying the structure and composition of riparian vegetation. Restoration of native plant species frequently proves to be ecologically and economically difficult. In the Muddy River drainage in the Mojave Desert (Nevada, USA), eradication of one the most aggressive invasive plants, Tamarix ramosissima (salt‐cedar), often reduces the structural and compositional diversity of the remaining vegetation. This can have negative effects on native animals, including birds. The objectives of our work were (i) to examine relationships between avian diversity and measures of vegetational diversity (species richness, dominance of non‐native plants and vegetation structure [total vegetation volume]), (ii) to explore the extent to which avian community composition was associated with vegetation composition (floristics) or vegetation structure (physiognomy), and (iii) to consider the potential effects of alternative land management and ecological restoration strategies on the biodiversity of birds and other native fauna in watersheds in the arid south‐western USA. Species richness of all birds and of breeding birds was best modelled by total vegetation volume alone. Neither species richness of plants nor dominance of non‐native plants had a statistically significant effect on species richness, abundance or evenness of birds. Species composition of birds between sites was more similar when floristics was more similar, and vice versa. Species composition of birds was not correlated with physiognomy. Species richness of native birds in the Muddy River drainage appears not to suffer from invasion of non‐native plants, provided that the vegetational community retains sufficient structural diversity. The composition of the bird community is closely related to floristics, and other taxonomic groups may exhibit different responses to vegetation structure and composition. Therefore, explicit strategies for landscape‐scale management, restoration and maximization of native faunal diversity should consider how removal of invasive plants may affect physiognomy and floristics of the vegetational community as a whole.

Conserving bird biodiversity: general principles and their application

Conserving bird biodiversity: general principles and their application

Keystone status of plateau pikas (Ochotona curzoniae): Effect of control on biodiversity of native birds

The plateau pika (Ochotona curzoniae) of the Qinghai–Xizang (Tibetan) plateau, People's Republic of China, has been considered a pest because it putatively competes with native livestock for forage and contributes to rangeland degradation. As a result the plateau pika has been poisoned across vast areas of the high alpine meadows of the plateau. The plateau pika has also been considered a keystone species for biodiversity on the plateau. As one test of the keystone species hypothesis, we investigated the effects of poisoning plateau pikas on avian species richness and abundance. We conducted standardized censuses of birds on a number of sites across the alpine grassland of Qinghai province on which pikas either had or had not been poisoned. Avian species richness and abundance were higher on non-poisoned sites, in particular for species that nest in pika burrows such as Hume's groundpecker (Pseudopodoces humilis) and six species of snowfinch (Montifringilla spp., Pyrgilauda spp.), and species that prey on pikas (upland buzzard, Buteo hemilasius; black-eared kite, Milvus lineatus). The plateau pika thus appears to be both an allogenic engineer and a keystone species. Poisoning pikas reduces biodiversity of native species on the Qinghai–Xizang plateau, therefore management decisions concerning plateau pikas should reflect caution and careful assessment.

Trophic Cascades and Biodiversity in Grand Teton National Park

The reintroduction of wolves into Grand Teton National Park has the potential of affecting species distribution patterns from the large ungulates down to the insect and plant communities. Trophic cascades, as these effects are called, epitomize the interconnectedness of ecological communities. My research team has been studying montane meadow biodiversity of plants, birds, and butterflies in the Grand Teton National Park since 1996. We have used satellite imagery to classify meadows along a moisture gradient into six categories (Ml-M6). Hydric meadows are dominated by willows and sedges, mesic meadows have a diversity of grasses and flowering plants, and xeric meadows are dominated by sagebrush and grasses. These meadows are important reservoirs of biodiversity in the arid Rocky Mountain ecosystems. We have identified a suite of species in each taxonomic group that are tightly linked with each of the meadow types. We expect that as wolves move into Grand Teton National Park and the surrounding areas, there will be changes in herbivory and species distribution patterns that will cascade through the system. This research will focus on monitoring montane meadow communities to test for trophic cascades in the willow and bird communities.

Birds of remnant vegetation on the Mornington Peninsula, Victoria, Australia: the role of interiors, edges and roadsides

Habitat loss and fragmentation on the Mornington Peninsula, Victoria, Australia, has resulted in a mosaic of forest patches, forest edges abutted by agricultural land and linear habitat strips amidst a human-modified land matrix. To examine the use of forest elements by the avifauna in this landscape, bird populations were sampled along fixed transects established within forest interiors, on forest edges and along forested roadsides. A total of 60 species was recorded during this study, five of which were introduced. Species richness and diversity did not differ significantly between the three habitat elements, but avifaunal composition varied considerably. The species assemblages of all habitat elements differed significantly, with forest interiors and roadsides showing the greatest difference and forest interiors and forest edges showing the least degree of difference. Forest-dependent bird species used both interiors and edges. Interiors differed from edges and roadsides in having lower abundances of open country species, predatory species and introduced species, A clear gradient of change in bird communities from forest interiors to roadside vegetation was observed. This study suggests that the interiors of medium-sized (<1 000 ha) patches may play an important role in conserving bird biodiversity on a local level as they provide refuge for forest-dependent native species in extensively cleared landscapes.

Conserving Bird Biodiversity: General Principles and their Application

Conserving Bird Biodiversity: General Principles and their Application