Tiny terminological disagreements with far reaching consequences for global bird trends

Various combinations of data and expert opinion have been used to select species for indices of bird trends. Commonly these indices break species into groups based on their habitat preference such as woodland specialist, farmland specialist and generalist birds. It is unclear what influence differences in how species are allocated to these groups might have on trends in these indices. There is uncertainty surrounding reported trends in these bird groups with studies variously showing declines or increases in prevalence. This is usually attributed to ecological factors but if studies classify bird groups differently this variation may be due to inconsistency in classification. Disagreement about whether these bird groups are stable, increasing or declining has the potential to obscure important changes in bird prevalence and impede appropriate, timely conservation.We examined how consistently European and Australian researchers classified woodland, farmland and generalist birds, and whether this affected the trends in indices of these groups. Researchers from both regions classified species differently, and the population trends seen in these groups were strongly affected by differences in classification. While all classifications we studied suggest that populations are consistently declining for Australian woodland and European farmland birds and increasing for European woodland birds. European generalist and Australian farmland and generalist birds may be seen as increasing or decreasing in prevalence depending on classification.Our results question the current practice of idiosyncratically classifying indicators in scientific research and conservation. Current practice is making it more difficult to infer whether, when and how to preserve bird groups in Europe and Australia, potentially leading to sub-optimal biodiversity outcomes. We offer suggestions for building consensus on how to classify these bird groups in order to provide more reliable evidence to support conservation decisions.     

Agricultural intensification and the collapse of Europe's farmland bird populations

The populations of farmland birds in Europe declined markedly during the last quarter of the 20th century, representing a severe threat to biodiversity. Here, we assess whether declines in the populations and ranges of farmland birds across Europe reflect differences in agricultural intensity, which arise largely through differences in political history. Population and range changes were modelled in terms of a number of indices of agricultural intensity. Population declines and range contractions were significantly greater in countries with more intensive agriculture, and significantly higher in the European Union (EU) than in former communist countries. Cereal yield alone explained over 30% of the variation in population trends. The results suggest that recent trends in agriculture have had deleterious and measurable effects on bird populations on a continental scale. We predict that the introduction of EU agricultural policies into former communist countries hoping to accede to the EU in the near future will result in significant declines in the important bird populations there.     

A Monte Carlo method to account for sampling error in multi-species indicators

The usefulness of biodiversity indicators strongly increases if accompanied by measures of uncertainty. In the case of indicators that combine population indices of species, however, the inclusion of the uncertainty of the species indices has shown to be hard to realize, usually due to imperfections in monitoring programmes. Missing values and time series of different lengths preclude the use of analytical approaches, whereas bootstrapping across sites requires the raw abundance data on the site level, which may not always be available. Sometimes bootstrapping across species rather than sites is opted for, but this approach ignores the uncertainty attached to species indices. We developed a method to account for sampling error of species indices in the calculation of multi-species indicators based on Monte Carlo simulation of annual species indices. The construction of confidence intervals enables various trend assessments, like testing for linear or smooth trends, testing for changes between two time points, testing the significance of a suspected change-point and testing for differences between two multi-species indicators. Here, we compare our method with conventional methods and illustrate the benefits of our approach using Dutch breeding bird indicators.     

Indices of bird-habitat preference from field surveys of birds and remote sensing of land cover: a study of south-eastern England with wider implications for conservation and biodiversity assessment

Aim This paper describes the development of novel indices of bird‐habitat preference to examine bird species’ use of habitats and their distributions relative to habitats. It assesses the implications for bird conservation regionally and the scope for biodiversity assessments generally. Location A 200 km by 400 km area of farmland with seminatural and urban areas, covering south‐eastern England. Methods Cluster analysis was used to link birds to landscapes. Cluster centroid coordinate values were processed to derive indices of bird‐habitat preference. Further developments assessed the relative values of individual habitats for birds. Results Clustering objectively linked birds to landscapes. Maps of the clusters showed strong regional patterns associated with distinctive habitat assemblages. Derived indices related bird species directly to individual habitats and habitats to birds. Even rare species and scarce habitats showed successful linkages, often to each other. Objective corroboration strongly supported the associations of coastal, wetland, urban and woodland birds and habitats; but, it suggested that farmland birds, whose numbers have nearly halved since 1977, may prefer alternative habitats. Main conclusions Land cover maps from remote sensing provide an effective way to link birds to habitats and vice versa. Thus, generalized habitat maps might be used to extrapolate localized or sample‐based bird observations or the results of autecological studies, helping to predict and understand bird distributions in the wider countryside. The weak links between farmland birds and farmland habitats in a region dominated by farming, suggests that reasons for the decline in farmland birds may be deep seated and thus hard to reverse. The procedures described are repeatable elsewhere and applicable more generally to evaluate landscapes and biodiversity. It is suggested that remote sensing could rarely be bettered as a means of assessing habitats, comprehensively, over wide areas, in most parts of the world.     

The past and future of farmland birds in Hungary

Capsule Populations of birds on farmland are larger and more stable in Hungary than in the UK and may provide baseline targets when planning population restoration programmes in more intensively farmed regions of Europe.

Aims To review the available evidence on farmland bird populations and their changes over the past century in Hungary, and to compare this with similar data for the UK.

Methods Published papers and grey literature were searched to determine long-term bird population trends for birds on farmland in Hungary, and for research evidence on the relationship between farmland management and bird diversity in Hungary.

Results Population density of common farmland birds is higher and trends are more positive in Hungary compared to the UK. These findings correlate with the recent change to generally less intensive agriculture in Hungary. However, while the birdlife associated with farmland in Hungary can be considered to have high diversity and density, it is still lower than it was in the first half of the 20th century and earlier. The few studies available showed that low-intensity traditional management promotes a rich biodiversity in both grasslands and arable systems in Hungary. Agri-environment schemes were introduced when Hungary joined the EU in 2004; however, their influence on biodiversity has not been systematically monitored.

Conclusions Insights emerging from farmland bird research in those European countries which still practice extensive agricultural techniques could be used to set general baseline targets for restoring biodiversity in regions where farmlands are now intensively managed. At the European scale urgent tasks are to: (1) investigate the relationships between management and bird diversity and density on a much wider geographical scale, (2) evaluate the geographical generality of the existing evidence base (which is mainly based on studies conducted in more intensively farmed regions), and (3) enhance the policy impact of conservation research.     

Applying red lists to the evaluation of agricultural habitat: regular occurrence of threatened birds,vascular plants,and bryophytes in field margins of Poland

Using the assessments of conservation status of flora and fauna, we discuss declining species in semi-natural field margins and stress the importance of these vanishing habitats. Seventy field margins in the diverse farmland of SW Poland were investigated with regard to their vascular plants, bryophytes and breeding birds. We checked the occurrence of threatened and conservation concern species, i.e. those listed in local, national or European threatened species lists, and birds with an unfavorable conservation status in Europe. Of a total of 673 species, 18 classified as threatened were recorded: 12 vascular plants (2.2 % of the total number of species), five bryophytes (5.6 %), and one bird species (2.0 %). Threatened plants occurred in 18.6 % of study plots, bryophytes in 20.0 % and birds in 12.9 %. Eleven bird species, noted in 95.7 % of study plots, had an unfavorable conservation status in Europe. Increasing volumes of trees and shrubs significantly increased the overall richness in each taxa. In percentage terms the occurrence of focal species in all three taxa tended to be higher in shrubby than in herbaceous and tree-lined margins. Our data demonstrate that field margins in Central European arable farmland regularly support rare and threatened species, and therefore deserve greater conservation efforts. Red lists along with alternative listing approaches can be employed to evaluate the biodiversity of fine-scale habitats, but their applicability depends on the taxonomic group and geographical scale of the lists, reflecting different conservation priorities.     

Geographic variation in the population trends of common breeding birds across central Europe

Recent declines of many European bird species have been linked with various environmental changes, especially land-use change and climate change. Since the intensity of these environmental changes varies among different countries, we can expect geographic variation in bird population trends. Here, we compared the population trends of bird species among neighbouring countries within central Europe (Czech Republic, Denmark, Germany, Switzerland) between 1990 and 2016 and examined trait-associations with population trends at both national and international scales. We found that Denmark had the highest proportion of declining species while Switzerland had the lowest. Species associated with farmland had negative trends, but the effect size tended to differ among countries. A preference for higher temperature was positively associated with population trends and its effect size was similar among countries. Species that were increasing across all four countries were associated with forest; while species that were decreasing across all countries were long-distance migrants or farmland birds. Our results suggest that land-use change tends to be a more regionally variable driver of common bird population trends than climate change in central Europe. For species declining across all countries, international action plans could provide a framework for more efficient conservation. However, farmland birds likely need both, coordinated international action (e.g. through a green agricultural policy) to tackle their widespread declines as well as regionally different approaches to address varying national effect trajectories.     

Multi-species spatially-explicit indicators reveal spatially structured trends in bird communities

Multi-species indicators are often used to assess biodiversity trends. By combining population trends across several species they summarise trends across a community. Composite indicators such as these are useful for examining general temporal patterns and may suggest important drivers of biodiversity change. However, they may also mask substantial spatial variation in population trends, particularly when they are calculated over large spatial regions. We produced spatially-explicit indicators for farmland and woodland bird communities in the UK and further separate these into trends for generalist and specialist species within each group. We found considerable spatial variation in the indicators, which is masked by indicators calculated at the national level. The farmland community indicator showed mostly positive trends in western areas and extensive declines in south-east England. The woodland community indicator showed a north–south divide, with increases in Scotland and northern England and stability in the southern regions. For both communities, indicator trends for specialist species were more negative than those for generalists. We found no significant difference in farmland community indicators between arable land and improved grassland. Woodland specialists had significantly more negative trends in broadleaf compared to coniferous woodlands, suggesting habitat-type is one of the drivers of changes in the woodland community. These spatial patterns in bird population trends may be used to highlight regional conservation priorities and identify where those may differ from the national scale. In combination with information about other environmental changes, they may also be used to develop hypotheses about potential drivers of change. We advocate that this approach is adopted for other taxa and geographical areas.     

Small things are important: the value of singular point elements for birds in agricultural landscapes

Farmland birds belong to the most endangered group of vertebrates in Europe. They are an important component of farmland biodiversity considering the numerous functions they perform (e.g. seed dispersal, improving germination, increasing gene flow, nutrient recycling, and pest control). Therefore, their decline imposes substantial risks on agricultural ecosystems. In general, farmland bird conservation includes land-use and management alterations leading to less-intensive farming and land-sparing for breeding habitats (e.g. agri-environment-climate schemes, and organic farming). However, theoretical concepts describing farmland biodiversity maintenance and applied conservation measures usually ignore the role of singular, often very small, natural or man-made elements in an agricultural landscape. These elements play a role in the populations of certain species, their biology and in the general species richness of farmland. Furthermore, the importance of these elements has never been empirically tested, which means that conservationists and practitioners are not aware of their measurable value for birds. Herein, we define and identify singular point elements in the agricultural landscape (SPELs) which are potentially important for breeding farmland birds. We also describe each SPEL and evaluate its importance for birds in farmland based on a systematic review of the available literature. Using a horizon-scanning technique, we then polled field ornithologists about their personal observations of birds in relation to SPELs and the evaluation of the potential roles of such structures for birds. We identified 17 SPELs that vary in naturalness and age: singular trees, singular shrubs, erratic boulders, puddles, electricity pylons, wind turbines, spiritual sites, hunting platforms, fence and border posts, wells, road signs, scarecrows, piles of manure, piles of brushwood/branches, piles of stones/debris, piles of lime, and haystacks. Analysis of the literature revealed knowledge gaps, because some SPELs are frequently mentioned in ecological studies (e.g. trees, shrubs, pylons), but others such as spiritual sites, stones, hunting platforms, wells, road signs, or piles of lime are ignored. Despite the fact that some authors incorporate the effects of some SPELs in their studies, little research to date has aimed to assess the impact of various SPELs on farmland bird species numbers and distribution. Horizon scanning revealed that ornithologists often observe birds on various SPELs and thus, attribute to SPELs many functions that are important for maintaining bird populations. Horizon scanning also highlighted the importance of SPELs for many declining bird species and suggested possible mitigation of negative changes in the agricultural landscape by retaining SPELs within fields. We suggest that a better understanding of the role of SPELs for farmland birds is required. We also recommend that SPELs are considered as a potential tool for the conservation of birds, and existing conservation programs such as agri-environment-climate schemes and organic farming should be updated accordingly. Finally, we suggest that SPELs are included in predictive models that evaluate habitat suitability for farmland biodiversity.     

The effect of land type diversity and spatial heterogeneity on farmland birds in Norway

The decline in farmland birds observed throughout Europe during recent decades has attracted much attention. Agricultural intensification or land abandonment are commonly forwarded as key drivers. Several countries have established agri-environmental schemes (AES) to counter these negative trends among farmland birds. This paper reports a study of the relationship between land use and bird species in the agricultural landscape of Norway. The main objective was to investigate the effect of spatial heterogeneity and diversity of land use on total richness and abundance of farmland birds at a national level.Monitoring the distribution and abundance of birds is part of the Norwegian monitoring programme for agricultural landscapes. The monitoring programme is based on mapping of 1 × 1 km squares distributed across the entire agricultural landscape. Within these squares permanent observation points are established for bird monitoring. Detailed interpretation of aerial photographs provides the land classification. We tested the relationship between landscape metrics at different levels of land type detail and species richness and abundance of farmland and non-farmland birds.There was a positive relationship between species richness and abundance of farmland birds and agricultural area. For non-farmland birds the relationship was negative. Spatial heterogeneity of land use was a significant positive factor for both farmland and non-farmland species. High land type diversity was positive for farmland bird richness, but negative for abundance. Non-farmland bird richness was not affected by land type diversity, but abundance had a negative response.The results presented in this paper highlight the importance of a spatial heterogeneous landscape. However, we also found that land type diversity could negatively affect the abundance of both farmland and non-farmland birds. Our findings suggest a need for different management approaches depending on whether the aim is increased species richness or abundance. Achieving both aims with the same means might be difficult. We thus suggest a need for land use analyses before proper management strategies can be implemented.     

Comparison of land cover and farming intensity-based models for mapping High Nature Value farmland in Cyprus

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.     

Monitoring change in biodiversity through composite indices

The need to monitor trends in biodiversity raises many technical issues. What are the features of a good biodiversity index? How should trends in abundance of individual species be estimated? How should composite indices, possibly spanning very diverse taxa, be formed? At what spatial scale should composite indices be applied? How might change-points--points at which the underlying trend changes--be identified? We address some of the technical issues underlying composite indices, including survey design, weighting of the constituent indices, identification of change-points and estimation of spatially varying time trends. We suggest some criteria that biodiversity measures for use in monitoring surveys should satisfy, and we discuss the problems of implementing rigorous methods. We illustrate the properties of different composite indices using UK farmland bird data. We conclude that no single index can capture all aspects of biodiversity change, but that a modified Shannon index and the geometric mean of relative abundance have useful properties.     

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. Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users.     

Ants and plants as indicators of biodiversity,ecosystem services,and conservation value in constructed grasslands

Grasslands are constructed for soil and wildlife conservation in agricultural landscapes across Europe and North America. Constructed grasslands may mitigate habitat loss for grassland-dependent animals and enhance ecosystem services that are important to agriculture. The responses of animal species richness and abundance to grassland habitat quality are often highly variable, however, and monitoring of multiple taxa is often not feasible. We evaluated whether multiple animal taxa responded to variation in constructed grassland habitats of southwest Ohio, USA, in ways that could be predicted from indicators based on quality assessment indices, Simpson diversity, and the species richness of ants and plants. The quality assessment indices included a widely used Floristic Quality Assessment (FQA) index, and a new Ant Quality Assessment (AntQA) index, both based on habitat specificity and species traits. The ant and plant indicators were used as predictor variables in separate general linear models of four target taxa—bees, beetles, butterflies and birds—with response variables of overall species richness and abundance, and subsets of taxa that included the abundance of ecosystem-service providers and grassland-associated species. Plant Simpson diversity was the best-fitting predictor variable in models of overall bee and beetle abundance, and the abundance of bees classified as ecosystem-service (ES) providers. FQA and plant richness were the best predictors of overall butterfly species richness and abundance. Ant species richness was the best predictor of overall bird species richness and abundance as well as the abundance of ES birds, while the AntQA index was the best predictor for the abundance of grassland bird and butterfly species. Thus, plant Simpson diversity and ant species richness were the most effective indicators for complementary components of grassland animal communities, whereas quality assessment indices were less robust as indicators and require more knowledge on the habitat specificity of individual ant and plant species.     

Using fledged brood counts of hedgerow birds to assess the effect of summer agri-environment scheme options

A key aim of many European agri-environment schemes (AES) is to improve biodiversity on farmland. In recent years, several countries have been looking at long term trends in the spring adult population size of a target group of farmland birds as an indicator of this. The overall trend in these indicators is however not upwards. While this might suggest we need to look at the design and deployment of habitat management options within schemes, there is an increasing view that we also need to refine and improve our indicators, or the way we monitor them.Relating spring adult bird population size to AES options is problematic not least because of the time lag between the deployment of those designed to enhance bird breeding success in summer, and the spring surveys the following year. At the other end of the scale detailed studies of breeding success in farmland birds have practical/cost restraints. We argue that to understand the impact on farmland birds of particular summer options within AESs we need to be able to estimate the breeding success of local bird populations quickly and cheaply. This would enable us to relate particular AES options to the breeding performance of the birds actually using them.Complementing a previous study of woodland birds, we assess the likelihood of encountering fledged broods of hedgerow nesting bird species during transect surveys without finding nests, and then apply a simple mark-recapture analysis technique to provide an index of breeding success for those species. Following spring adult assessments, counts of fledged broods were undertaken four times a week during April, May, June and July, in four 2.5 km hedgerow transects, at four sites in southern England in 2010. Mean daily detection probabilities of fledged broods of 16 common hedgerow birds were calculated from these counts using the software Presence. For 15 out of these 16 species these detection probabilities were sufficiently high for a programme of fledged brood surveys, involving just two or three visits per week from mid-May to mid-July, to provide a useful estimate of breeding success.The survey technique and associated analyses make certain assumptions when providing estimates of breeding success and these are discussed. Little is known about initial dispersal in passerine fledglings and a study in hedgerows may be useful here. However our pilot study suggests that the method could have application as a relatively easily derived productivity index for hedgerow birds, and hence an additional method available to study the impact of certain AES options on indicator species, or for research studies.     

Moving Window Abundance – A method to characterise the abundance dynamics of farmland birds: The example of Skylark (Alauda arvensis)

Farmland birds are important indicators of the state of biodiversity in rural landscapes, and the occurrence and abundance of birds contribute to their importance as bioindicators. However, the measurement of farmland bird abundance can be difficult. The rapid growth of crop plants in the spring combined with disturbances related to farming practices, such as weed and pest control and other measures, can profoundly change the habitat suitability of arable fields for birds within a short period of time. Consequently, the existing dynamics must be incorporated into the applied methods, and a single value of bird abundance during the breeding season is insufficient to characterise the habitat functions of arable land. The abundance of farmland bird species is influenced by crop specific features, which profoundly change within the breeding season and which we have described using a novel concept called Moving Window Abundance. Based on field surveys in 29 observation areas within arable landscapes, each 1 km², Skylark with territorial behaviour were counted using a mapping method related to the habitats and growth of field crops, such as wheat and maize. To describe the dynamic characteristics of the abundance during the breeding season over the time period from 16 March to 18 July, three methods of Moving Window Abundance were tested: patchy, adjacent and overlapping. These methods differ in the time-space continuity of the considered time window throughout the breeding season. In the Patchy Moving Window Abundance method, we used the exact days in which field surveys were conducted throughout the entire time period of the field surveys. However, with the Adjacent Moving Window Abundance method, the time window included five-day, ten-day and semi-monthly adjacent windows; in the Overlapping Moving Window Abundance method, the time window shifted daily, with five-day, ten-day and semi-monthly overlapping windows used in the calculation procedure. The results indicated that the dynamic nature of Skylark abundance (i) reached a maximum level in the first breeding period in the agricultural landscape and (ii) exhibited large variations in level and time within the various field crops. Therefore, abundance was not described conventionally using a single numerical value but rather using mathematical functions based on the spatial scale of the landscape and habitat. We conclude with recommendations for further research to standardise farmland bird monitoring.     

Indexing European bird population trends using results of national monitoring schemes: a trial of a new method

Many European countries have annual breeding bird monitoring schemes based on nationwide samples; most are in northern and western Europe. We have developed a method to produce yearly population indices of bird species across countries by combining the results of existing national schemes. The method takes into account the differences in population sizes per country, as well as the differences in field methods, and the numbers of sites and years covered by the national schemes. In order to test the method, we collected raw data from a number of countries and applied an index method to produce scheme results per country. Data were collected for five farmland species (Lapwing Vanellus vanellus, Linnet Carduelis cannabina, Skylark Alauda arvensis, Whitethroat Sylvia communis and Yellowhammer Emberiza citrinella), from seven countries (UK, Netherlands, Denmark, Germany, Finland, Latvia and Estonia) for a 20-year period (1978–97). The trial demonstrated that it was possible to combine national indices to provide supra-national yearly totals and their standard errors; the results were similar to those produced when the raw data were used. Thus, yearly European indices can be produced by exchanging only limited amounts of information, that is the national yearly indices of each species or, preferably, the yearly population numbers and their standard errors. At a European scale, the populations of the five species selected have changed considerably. In western Europe (UK, Netherlands, Denmark and former West Germany combined), Linnet, Skylark and Yellowhammer have declined and Whitethroat has increased. Most changes occurred during the first ten-year period (1978–88). The changes in eastern Europe (the remaining countries) were less clear, in part because the statistical power of the national schemes is as yet limited.     

Grassland versus non-grassland bird abundance and diversity in managed grasslands: local,landscape and regional scale effects

Declines of West European farmland birds have been associated with intensive agricultural practices, while in Central and Eastern European countries grasslands still harbour a diverse and unique bird community. However, in these countries comparative studies on the effects of agricultural intensity on biodiversity are virtually missing. We compared bird communities of paired extensively and intensively grazed cattle pastures in three different regions of the Hungarian Great Plain. The influence of grazing intensity, landscape and regional effects were tested on the abundance and species richness of two ecological groups of bird species (grassland and non-grassland birds), as well as on the abundance of the three commonest grassland bird species (Skylark, Yellow wagtail, Corn bunting) in linear mixed models. We found significant effects of grazing intensity on the abundance of grassland birds, which were more abundant on the extensive sites, whereas no effects were found on non-grassland birds. This could be explained by a closer dependence of grassland birds on grasslands for nesting and foraging, whereas non-grassland birds only used grasslands opportunistically for foraging. Landscape effect was shown on grassland bird abundance, but not on non-grassland birds. The regions did affect only the species richness of grassland birds. At species level, the effect of management was significant for the three commonest grassland species, which were more abundant on the extensive fields in all regions. Additionally, on Skylark abundance landscape and regional effects were also shown. These findings suggest that conservation of biodiversity in agricultural systems requires the consideration of landscape perspective to apply the most adequate management.     

Effects of perennial wildflower strips and landscape structure on birds in intensively farmed agricultural landscapes

Farmland bird populations are in a deep crisis across Europe. Agri-environment schemes (AES) were implemented by the European Union to stop and reverse the general decline of biodiversity in agricultural landscapes. In Germany, flower strips are one of the most common AES. Establishing high-quality perennial wildflower strips (WFS) with species-rich native forb mixtures from regional seed propagation is a recent approach, for which the effectiveness for birds has not yet been sufficiently studied. We surveyed breeding birds and vegetation on 40 arable fields with WFS (20 with single and 20 with aggregated WFS) and 20 arable fields lacking WFS as controls across Saxony-Anhalt (Germany). Additionally, vegetation composition, WFS quantity and landscape structure (e.g. distance to nearest woody element) were considered in our analyses. All WFS were established with species-rich native seed mixtures (30 forbs) in agricultural practice as AES. Arable fields with WFS had a higher species richness and territory density of birds than controls, confirming the effectiveness of this AES. A forb-rich vegetation was the main driver promoting birds. Flower strip quantity at the landscape level had positive effects only on bird densities, but also single WFS achieved benefits. A short distance from WFS to woody elements increased total bird species richness. However, the density of farmland birds, which are target species of these AES, were negatively affected by the proximity and proportion of woody elements in the vicinity. The effect of the proportion of non-intensively used open habitats and overall habitat richness was unexpectedly low in the otherwise intensively farmed landscape. Species-rich perennial WFS significantly promoted breeding birds. Successful establishment of WFS, resulting in high-quality habitats, a high flower strip quantity as well as implementation in open landscapes were shown to maximise the effectiveness for restoring declining and AES target farmland birds.