Miliaria Calandra Research Articles

Fifty years of monitoring changes in the abundance of invertebrates in the cereal ecosystem of the Sussex Downs, England

Abstract Changes in insect abundance are receiving much attention, with agricultural intensification considered to be one of the main drivers of decline. We report on changes in invertebrates collected in cereal fields in Sussex, Southern England, UK, from 1970 to 2019. Samples were taken using D‐vac suction sampling in the third week of June from an average of 95 cereal fields per year (4757 samples in total, comprising 2,983,124 individual invertebrates identified mainly to family level). The study area comprises 12 farms, whose land use, crop rotations and intensity of pesticide use were also recorded, showing marked changes over time. Overall invertebrate abundance declined by 37% across all taxa, and by 48% when excluding the most numerous taxa (Collembola, Aphididae and Thysanoptera). Declines in abundance were identified for 47% of 51 non‐overlapping taxa at the order or family level, increases for 16% and no change for 37%. Most declines occurred in the first decade of the study, most increases in the 1990s. Latterly there have been further declines from 2010. As functional groups, mycetophages, phytophages, predators (both aphid‐specific and polyphagous), parasitoids and cophrophages declined significantly, while there was no detectable change in pollinators. Four of five measures of avian chick‐food invertebrate abundance declined significantly, while one (corn bunting chick‐food index) showed no detectable change. A multivariate constrained redundancy analysis revealed that cropping, field size, pesticide use and weather all significantly explained the variation in the abundance of the 51 non‐overlapping taxa. For functional groups, significant explanatory variables were weather and pesticide use. Changes in farming practices and adoption of measures such as integrated pest management, regenerative farming, agri‐environmental scheme options and intercropping could help to mitigate the factors associated with decline.

Bagaza Virus in Wild Birds, Portugal, 2021.

Bagaza virus emerged in Spain in 2010 and was not reported in other countries in Europe until 2021, when the virus was detected by molecular methods in a corn bunting and several red-legged partridges in Portugal. Sequencing revealed high similarity between the 2021 strains from Portugal and the 2010 strains from Spain.

Conservation potential of semi-natural habitats for birds in intensively-used agricultural landscapes

Agricultural intensification resulted in substantial loss of farmland biodiversity. Semi-natural habitats may be viewed as potential buffers of these adverse impacts, but a rigorous assessment of their capacity for supporting farmland biodiversity is lacking. In this study, we explored conservation potential of two different types of semi-natural habitats for birds in intensively-used agricultural landscapes – farmland hedges (i.e., linear strips of shrubby and tree vegetation) and open scrubland (i.e., scattered shrubs and abandoned orchards). Specifically, we tested whether the abundance and species richness of birds differ between these habitats considering various species traits, such as habitat affinity (i.e., forest, farmland and urban species), diet specialization (i.e., animal eaters, plant eaters, and omnivores) and conservation status (Species of European Conservation Concern). We found that open scrubland hosted on average 37.9 bird species and 122.6 individuals per 1 km2 of the transect, whereas farmland hedges hosted only 19 species and 61.8 individuals per 1 km2 of the transect. However, results have substantially changed if we considered the area of suitable habitat into account. More specifically, open scrubland hosted more bird species and individuals when we considered open habitat species and the area of open habitats, whereas farmland hedges had higher species diversity and individuals of woodland bird species when we considered the area of woodland habitats. Similarly, analyses of habitat affiliations of individual species corresponded to the whole-community patterns; and revealed that several woodland bird species were mainly associated with farmland hedges (e.g., Chaffinch Fringilla coelebs, Common Nightingale Luscinia megarhynchos and Blackcap Sylvia atricapilla), whereas the open scrubland was preferred by open habitat bird species (e.g., Corn Bunting Emberiza calandra, Quail Coturnix coturnix and Skylark Alauda arvensis). These results demonstrate that semi-natural habitats, both open scrubland and farmland hedges, have large potential for promotion and conservation of bird communities within intensively used agricultural landscapes, as both may have represented suitable habitats for species with different ecological requirements. Therefore, management measures focused on the enlargement of the area of these habitats, in combination with suitable management (e.g., regulating the progress of natural succession in open scrubland; increasing structural diversity of existing farmland hedges), may substantially contribute to bird conservation within agricultural landscapes.

Detection Rate of Bird Species and What It Depends on: Tips for Field Surveys

Bird counting inevitably suffers from imperfect detection, which varies across species, habitats, period of the day, and seasons. Although various modeling techniques have recently been developed to account for this phenomenon, the biological basis of natural variation in detection remains insufficiently known. This study examined the bird species’ detection rate throughout the day, considering their body mass and diet type, concerning the environment and weather characteristics. Species detection rates were significantly affected by the number of individuals of that species but were unrelated to body mass. Overall, species with the highest detection rate were Corn bunting, Blackbird, European robin, House sparrow and Common chiffchaff. Granivores-insectivores and insectivores showed significant differences in detection rates throughout the day among habitats, with higher detection rates in grasslands during the afternoon. Insectivores showed higher detection rates in farmland during midday (warmest time of the day). Granivores, omnivores and scavengers did not show changes in detection rates in different day periods. Such patterns in daily detection rates were significant even when considering abundance and total species richness in each community. Finally, cloudiness was unrelated to the overall detection rate of birds, while temperature and wind affected detection rates in some guilds. Our findings provide some advice for choosing a suitable ornithological sampling method by considering the avian communities composition in combination with the type of environment, the diet of bird species, and the period of the day.

Spatial Heterogeneity of Steppe Bird Community in the Azov-Black Sea Enclave of the European Dry-Steppe Zone (Southern Ukraine)

Over the period 2007–2019, the author’s censuses of steppe birds in the Azov-Black Sea dry-steppe enclave determined five species as dominants and co-dominants by their abundance. Thus, Melanocorypha calandra dominates throughout the whole area, Emberiza calandra dominates in 4 subregions and co-dominates in 5 subregions, Motacilla feldegg, Emberiza hortulana, Anthus campestris, Alauda arvensis dominate in 1 subregion and do not dominate or co-dominate in 1–4 subregions. There is a general increasing trend in the total abundance of steppe birds and the number of their rare breeding species from north-west to south-east, whereas the number of their dominants and co-dominants grows in the opposite direction. According to the list, the correlation between the dominants/co-dominants and the number of rare breeding steppe species, it was revealed that the most valuable for the support of the steppe bird populations are subregions with the largest areas of virgin steppes (the Kerch Peninsula, Western and Central Crimea). The least important are the subregions with the highest degree of anthropogenic transformation (northern part of the Syvash region, western part of the Black Sea region) and the Lower Dnipro wetlands. Therefore, it is a high abundance of steppe birds and the maximum number of rare steppe species which should be a specific ornithological indicator of the status of zonal landscapes in the dry steppe zone (especially within protected natural areas of Ukraine) rather than general avian species diversity including introduced, invasive species, synanthropes, etc.

Орнітофауна лучних екосистем у прикордонних районах Львівщини та Волині

Meadow ecosystems comprise a significant part of the area of Ukraine, especially in its western regions. Those ecosystems are subjects of concern today because of the active agricultural use and droughts that also threatens the animal population of meadows, including birds. Studies of meadow bird species of western Ukraine are limited to atlases, which results in a lack of precise data. This work was part of an international project on the conservation of the great snipe Gallinago media and allowed us to collect valuable data on the abundance and occurrence of meadow bird species nearby to the Polish and Belarusian borders of Ukraine — territories that are commonly ignored by Ukrainian researchers. The surveys of meadow birds conducted near the Ukrainian-Polish border in 2020 have shown that the general state of the marshes is worse compared to 2019: even close to the Western Bug river, only deep oxbow lakes were wet or contained some water, but minor lakes and wetlands of the valley were found to be dry. In total, we observed 141 bird species belonging to 17 orders. Among them, 26 were common by abundance and frequency, such as the great egret Ardea alba, the white stork Ciconia ciconia, the common quail Coturnix coturnix, the corn crake Crex crex, the northern lapwing Vanellus vanellus, the common redshank Tringa totanus, the common cuckoo Cuculus canorus, the Eurasian skylark Alauda arvensis, the meadow pipit Anthus pratensis, the western yellow wagtail Motacilla flava, the sedge warbler Acrocephalus schoenobaenus, the marsh warbler A. palustris, the great reed warbler A. arundinaceus, the common whitethroat Sylvia communis, the whinchat Saxicola rubetra, the thrush nightingale Luscinia luscinia, the common linnet Linaria cannabina, the corn bunting Emberiza calandra, the common reed bunting E. schoeniclus, and 7 more species, which were observed frequently though are not typical marshland species. We have identified the species that can be used as indicators of parameters of marsh ecosystems such as grass height (corn crake, western yellow wagtail, and sedge warbler), moisture (common redshank, common cuckoo, and the sedge and great reed warblers), and habitat type (corn crake, European bee-eater Merops apiaster, sedge warbler, common reed, and corn buntings).

Mid-Late Pleistocene Neanderthal landscapes in southern Italy: Paleoecological contributions of the avian assemblage from Grotta del Cavallo, Apulia, southern Italy

We present a detailed paleoecologic analysis of avian assemblages from the Mousterian layers of the Middle Paleolithic Grotta del Cavallo site in southern Italy. Findings improve knowledge of the landscape that was exploited by Neanderthals. During the MIS 7, 6 and 3, the cave was surrounded by extensive grasslands and shrublands, locally interspersed by open woodland and rocky outcrops, whereas the coastal plain (currently underwater) hosted wetlands. Water bird taxa show an increase in population size during the cool-temperate climatic interval attributed to MIS 3, possibly linked to more humid conditions or a shorter distance between the wetland settings and the cave, compared to the previous glacial phase (MIS 6). In addition, coverage-based rarefied richness suggests higher avian diversity during MIS 3, which may reflect greater landscape heterogeneity due to the presence of wetland habitats. The tentative discovery of Branta leucopsis, together with several bird species currently found at higher altitudes, reinforces geochemically-derived palaeoclimate inferences of cooler than the present conditions. These assemblages also include the first fossil occurrence of Larus genei worldwide, the first Italian occurrence of Emberiza calandra, the oldest Italian occurrence of Podiceps nigricollis, and the occurrence of the rarely reported Sylvia cf. communis. Taphonomic analyses indicate that bone modifications are mainly due to physical syn- and post-depositional processes, and that the assemblage mainly accumulated through short-range physical transport and the feeding activities of nocturnal raptors.

A fine-grained bird Atlas as tool for spatial monitoring: a case study from a remnant wetland during the breeding period (Torre Flavia, central Italy)

During the 2019 breeding period we carried out a bird atlas for a small coastal natural reserve (Torre Flavia wetland, Special Protection Area IT6030020, central Italy), comparing quantitative data of spatial occurrences with records from an analogous study carried out in 2005. From 2005 to 2019 some water-related species increased their frequency of occurrence (Fulica atra, significantly). Among the reed and rush-bed species, Acrocephalus scirpaceus spatially increased and Cisticola juncidis decreased significantly. Among ecotonal, synanthropic and open habitat species, we registered a significant increase of Chloris chloris. A decreasing trend of Passer italiae, Saxicola torquatus, Emberiza calandra, although not significant, may be probably linked to regional or continental factors. Both causes at local (reedbed expansion, rushbed reduction, water-level management) and at larger scale (decline in their continental range) can explain the observed changes in spatial occurrences during this medium-long temporal range. Local atlases can be quick tools useful to drive management strategies in remnant wetlands.

Identifying agricultural pesticides that may pose a risk for birds.

In this study, we analyze changing patterns of pesticide use in agriculture in Great Britain over the 1990–2016 period, with respect to the risk they pose to birds. The weight of pesticides applied decreased by 51% between 1990 and 2016, but the area treated increased by 63% over the same period. Over this period, there has been considerable turnover in the pesticides used. The European Union (including Great Britain until 2020) has restricted or banned many pesticides for agricultural use, including organophosphates and carbamates. However, new generations of active substances have been introduced, such as the neonicotinoids, some of which have since been banned. In this analysis, we estimate the annual ‘toxic load’ of agricultural pesticide use in Great Britain for birds, measured as the total number of LD50 doses for corn buntings, Emberiza calandra. We have previously performed similar analyses for bees, for which the total toxic load increased six-fold during this period. In contrast, for birds the total toxic load fell by 80.5%, although still correspond to 8.3e+11 corn bunting LD50 doses in 2016. The decrease in toxicity is largely due to declining use of highly toxic organophosphates in recent years. We identify the pesticides in current use that may pose the highest risk to birds, which include a mix of insecticides, herbicides, fungicides, molluscicides, acaricides and plant growth regulators. The insecticide ethoprop was ranked highest in 2016, with a toxic load of 71 billion potential corn bunting kills. Some of the other chemicals presenting a high toxic load, such as the herbicide chlormequat, are not highly toxic to birds (in terms of LD50) but are used in very large quantities. However, it is important to stress that, in reality, only a tiny proportion of pesticides applied will be ingested by birds, and this will vary according to timing and method of application, persistence of the active substance and many other factors. We further note that impacts of pesticides on birds might often be indirect, for example via depleting their food supply, and that sublethal impacts may occur at much lower doses than the LD50, neither of which do we investigate here. Nonetheless, we suggest that this is a useful approach to highlight pesticides that might be worth closer study with regard to possible impacts.

Livestock species and grazing rotational patterns modulate grassland bird assemblages in Mediterranean drylands

In the last decades, western Iberian Mediterranean drylands have experienced a shift from extensive sheep to beef-cattle farming. In this 5-year study in Évora region (Southern Portugal), we investigated the role of livestock species in favouring grassland bird habitat suitability, starting from the hypothesis that livestock species complement bird habitat requirements under contrasting grazing rotation patterns and annual rainfall conditions. Field methods were based on bird counts and data was analysed using Generalized Linear Mixed Models. Model ranking and selection were based on the estimation of second-order Akaike Information Criterion (AICc). The grazing rotation pattern was the variable that best explained bird richness and total bird abundance, whereas livestock species had a minor effect. The corn bunting, the common quail and the crested lark presented higher abundances in fields grazed by sheep whereas calandra larks showed opposite trends. Except for the crested lark, grazing rotation pattern was the variable that best explained the abundance of individual species. Fields under short-medium duration rotational grazing revealed lower bird abundance and richness. Interactions between livestock species and grazing rotation were only found for the zitting cisticola. Bird species preferences relative to livestock species were found to be independent of annual rainfall conditions. We conclude that shifting from sheep to cattle grazing in Iberian Mediterranean drylands may favour light to moderate changes in the species identity of grassland bird assemblages (i.e. certain species appear or increase while others decrease or disappear from the assemblage), although no significant changes were found for bird richness. However, the grazing rotational patterns had greater effect on species total abundance and richness than the particular livestock species. Given the alarming decline of grassland birds in Europe, changes in grassland bird assemblages associated to the sheep-to-cattle shift currently occurring in Iberia may become an important issue within the framework of future European agricultural policy and should be subject to long term monitoring.

Could Meadow Passerine Distribution Within a Grassland System be Influenced by Spatial Variation in the Mowing Schedule?

This study explored meadow passerine capacity to select habitat conditions likely to preserve their breeding success. We observed the variation in bird abundance, assessed with the point count method, over a 25-year period (1993–2017) within two phytosociological facies of the hay-meadows in the lower Saone Valley (3.000 ha), eastern France: a meso-hygrophilic facies characterized by increasingly early mowing, and a hygrophilic facies mown later, with thereby a lower risk of nesting failure. At the beginning of the monitoring (1993–2001), birds were evenly distributed within the two facies. Later on, as more than 90% of meso-hygrophilic meadows were already mown by July 1, birds became more abundant in the hygrophilic facies. This trend was observed in each of the two most abundant species, the Whinchat Saxicola rubetra and the Corn Bunting Emberiza calandra. In two hygrophilic areas (55 and 76 ha) and two meso-hygrophilic areas (49 and 116 ha), passerine territories were mapped in 2011 with the territory mapping method and invertebrates were captured weekly on transects with colour plates and Barber traps. In spite of substantially higher invertebrate abundance, passerine territory density was lower in meso-hygrophilic study sites (6.4 territories/ 10 ha vs. 10.6). Within each study site however, captured invertebrates were more abundant in the areas selected by territorial birds. In fact, bird abundance estimated from point counts in 2011 varied negatively with the percentage mown by July 1 within a 200m-radius in 2010. This apparently adaptive behaviour leading to a selection of later mown fields seemed to be successful since bird abundance increased until 2010. However, after a succession of extreme climatic events (droughts, late floods), passerine abundance declined thereafter in both facies.

Energy crops affecting farmland birds in Central Europe: insights from a miscanthus-dominated landscape

The expansion of energy crops such as miscanthus Miscanthus x giganteus has changed the habitat of European farmland birds. However, most studies on the subject are based in Western Europe. We surveyed the avian community in a sample bioenergy landscape in Poland to investigate the pattern of use of the crop by birds in Central Europe. During a year-long survey, 80 species were noted, with 32 sighted in miscanthus. The number of bird sightings was negatively correlated with the area covered by miscanthus in study plots. In contrast to results from Western Europe, most woodland-generalist bird species tended to avoid miscanthus. Farmland species (e.g. the corn bunting Miliaria calandra; the tree sparrow Passer montanus; the starling Sturnus vulgaris; the yellowhammer Emberiza citrinella) were less frequently sighted in the crop than in other habitats. Only a few species were sighted more often in miscanthus than in other habitats, e.g. the marsh warbler Acrocephalus palustris; the reed bunting Emberiza schoeniclus; the whinchat Saxicola rubetra. The potential impact of expanded miscanthus cropping on bird communities in Central and Eastern Europe may diverge from predictions derived from studies based in Western Europe due to differing habitat preferences and bird densities between the regions. For a majority of farmland species, the crop may constitute only a suboptimal, supplementary habitat, with only a few birds potentially adapting to the exploitation of bioenergy plantations.

Mismatches between habitat preferences and risk avoidance for birds in intensive Mediterranean farmland

Land use intensification may create habitats that organisms perceive as suitable, but where reproduction or survival is insufficient to maintain self-sustaining populations. Such conditions may qualify as ecological traps, but their existence is often hard to prove. Here, we provide a practical framework to evaluate a potential ecological trap resulting from mismatch between habitat preferences and predation risk, focusing on ground-nesting farmland birds of conservation concern. The framework is based on species-specific associations with safe or unsafe habitat types (i.e. field and landscape types with high or low nest survival), and the occurrence of risk avoidance (i.e. negative responses to predator abundances or to nest failure rates after controlling for habitat effects). Bird densities were far more influenced by field characteristics than landscape context. Corn bunting and fan-tailed warbler were associated with tall swards (safe habitats), and did not show risk avoidance. Tawny pipit and and Galerida larks were associated with short swards (unsafe habitats), with the former avoiding fields with high nest predation rates, and the later avoiding high mongoose abundances. Short-toed lark was associated with fields with short swards and low nest trampling rates. Results suggest that short-toed lark may be the most vulnerable to ecological trapping, because it nests on unsafe habitats and did not show predation risk avoidance. Our approach provides a practical first step to infer vulnerability to a potential ecological trap, though further research is needed to confirm this effect. Management actions increasing nest survival in short sward fields will likely favour grassland bird conservation in intensive Mediterranean farmland.

The effects of forest succession and grazing intensity on bird diversity and the conservation value of a Northern Adriatic karstic landscape

We studied the effects of different land uses on conservation value and bird diversity in a Northern Adriatic karstic landscape. Our research area was situated in SW Slovenia and was covered with dry pastures and meadows in different stages of forest sucession and with different grazing intensities. We surveyed birds in 2007 and 2012 using the line transect method, with 50.4 km being covered each year. In the analysis we divided the survey transects into 200 m tiles which were used as statistical units in the analysis. We then modelled conservation value, bird diversity and bird abundances with different land uses; we used boosted regression trees as a modelling tool. Canonical correspondence analysis showed that a distinct group of birds occurred on tiles with higher grazing intensity. The species in this group also had significantly higher abundances in 2012 than in 2007. Forest succession was the most important predictor of SPA conservation value (Special Protected Areas according to the Directive on the conservation of wild birds of the European Union) and had negative effect on it; grazing intensity had a unimodal positive influence on conservation value and was most beneficial at low intensity. The model for the European conservation value showed a rather low predictive power. Farmland bird diversity was also negatively affected by forest and positively by grazing intensity. For the four Natura 2000 species—protected species in the SPA Kras (Woodlark Lullula arborea, Red-backed Shrike Lanius collurio, Corn Bunting Emberiza calandra and Skylark Alauda arvensis), forest cover also had a negative effect. Grazing intensity had a positive effect for Woodlark, Red-backed Shrike and Skylark. The highest SPA conservation value and farmland bird diversity could therefore be achieved in a landscape with as low a forest succession as possible and grazing present but at low intensity. We recommend inclusion of appropriate measures in the agri-environment schemes (CAP pillar II) of Rural Development Programmes of the countries in the region with similar areas. The payments should be sufficiently stimulative to reopen the large areas subject to forest encroachment in the Northern Adriatic hinterland.

Are Landscape Configuration Metrics Worth Including When Predicting Specialist and Generalist Bird Species Density? A Case of the Generalised Additive Model Approach

Due to the complexity of factors that influence species density on a large geographical scale, the effectiveness of the species distribution model (SDM) is still debatable. That is why the buffer zone (the area within 100 m from the outside edge of the patch), the core, i.e. (patches excluding the 100 m buffer zone from the patch’s edge) and patch shape are explored in this study to see how they affect the density of habitat specialist and generalist bird species. Two sets of generalised additive models were generated separately for each of the four bird species: One set of models contained landscape configuration metrics as an additional predictor variable, and the other did not. The results showed that models including the core, the buffer zone and the shape of patches turned out to be definitely better than models without them. Specialist species, the Corn bunting and the Wood nuthatch, are more likely to occur in the core of the preferred patches, and they choose those of a simple shape; while generalist species, the Whinchat and the Tree pipit, are more probable to be present in the buffer zone of a more complicated shape. Thus, the results clearly show that specific landscape configuration models can improve the predictive power of SDMs and can be used as an effective tool for predicting species density and functional bird diversity (specialist and generalist). Furthermore, from the applied ecology perspective, detailed landscape configuration metrics can be considered as a surrogate of elusive habitat conditions.

On habitat characteristics driving meadow passerine densities in lowland hay-meadow systems in France

For meadow bird conservation in Europe, promoting specific farming models in their remaining strongholds could be a necessary complement to the ongoing agri-environmental policy. This study aims at understanding the main drivers of meadow passerine density in the objective of guiding conservation policies. The data were collected in 56 lowland hay-meadow regions important for grassland bird breeding in France. The objective was to explain, using GLMMs, the variation in meadow passerine density, measured annually in 490 12-ha plots during the period 2006–2010 by the count point method. Explanatory variables enabled us to describe farming management, sward structure and habitat size. Passerine density (all species except the skylark Alauda arvensis) depended on the extent of habitat available and on the percentage of meadow already mown on June 20. More specifically, the skylark was attracted to low, floristically rich and early mown swards, the whinchat Saxicola rubetra and the yellow wagtail Motacilla flava to large areas of favourable habitat, and the corn bunting Emberiza calandra to floristically rich meadows mown later than June 20. Extensive farming models based on late mowing in the largest habitat units should therefore be a target for meadow passerine conservation. The skylark was an exception. Because of its apparent tendency to use early mown grasslands, we recommend to rather invest on alternative habitats for sustaining the demography of this species.

The Proportion of Cropland Influences Negatively the Occurrence of Breeding Birds in an Alkali Grassland Habitat in NW Serbia

Abstract Grasslands host a high diversity of plant and animal species. In Serbia, most alkali grasslands are located in the province of Vojvodina. The majority are not subject to conservation. The aim of the study was to investigate the relationship between the proportion of croplands and (1) the number of breeding species and (2) the number of breeding pairs in the alkali grasslands of the upper Mostonga River catchment basin (NW Serbia). The size of the study area was 400 ha. Birds were surveyed along seven parallel transects eight times per breeding season. Lengths of the cross sections of both grasslands and croplands were measured. The proportion of croplands per transect was calculated by dividing the total length of cross sections of croplands by the total length of transect. The relationship between the proportion of croplands and the number of breeding pairs and the number of breeding species, respectively, was studied using simple linear regression. We recorded a total of 171 nesting pairs belonging to 23 species in the alkali grassland investigated, with breeding densities between 2.2 and 10.3 pairs per 10 ha. The number of species per transect ranged between 6 and 11. The most abundant species were Skylark Alauda arvensis, Yellow Wagtail Motacilla flava and Corn Bunting Emberiza calandra. The numbers of breeding pairs (F6 = 21.761, P < 0.0001) and of breeding species (F6 = 13.758, P = 0.001) were both influenced negatively by the proportion of croplands. These findings highlight the need for coordinated conservation measures on the alkali grasslands of Vojvodina.

Birds and plants: Comparing biodiversity indicators in eight lowland agricultural mosaic landscapes in Hungary

This study compares biodiversity indicators based on plant and bird communities in eight mosaic landscapes in Hungary, dominated by a mixture of agro-ecosystems and grasslands. The eight landscapes were selected to represent the diversity of the mixed agricultural landscapes of South-East Europe, where a mosaic pattern of intensively managed farmlands and high nature value semi natural grasslands is still relatively prevalent. Bird communities were described using several assemblage-level (species number, total abundance, and Shannon diversity of the assemblage, based on 15 pre-selected key farmland bird species), as well as species-level (presence/absence of the 15 bird species) indicators, which were checked against a synthetic landscape quality indicator describing the degradation of the local plant communities with respect to an ideal baseline (vegetation-based natural capital index, NCI). The authors were interested if and how the assemblage- and species-level bird indicators can describe landscape quality in South-East European agricultural mosaic landscapes.It was found that assemblage-level bird indicators were poorly associated to the landscape quality measured in terms of NCI: only total abundance correlated significantly with NCI. On the other hand, species-level indicators were much more successful in predicting landscape quality. Six (Alauda arvensis, Emberiza calandra, Falco tinnunculus, Motacilla flava, Limosa limosa, Vanellus vanellus) of the 15 farmland bird species studied showed significant positive correlation with NCI, while three species (Emberiza citrinella, Galerida cristata, Sylvia communis) exhibited negative correlations. We also found that it was possible to draw conclusions about the landscape quality in an agricultural landscape based on the bird communities better, than to predict the bird assemblages from vegetation condition.The negative correlations for species that indicate good quality habitats in Western Europe, underline the context specificity of biodiversity indicators: whereas the conditions preferred by these species can be considered relatively natural in Western Europe, they correspond to relatively degraded habitats in South-East Europe. The nine farmland bird species which showed a significant connection to NCI can be seen as potential candidates for a regional Farmland Bird Index customized for agricultural landscapes in South-East Europe, in the Pannonian biogeographic region, or in Hungary.

The influence of crop tiller density on the breeding performance of a cereal‐nesting specialist

Summary In the pursuit of maximizing agricultural yields and profits, crop management under intensive agriculture has reduced the heterogeneity of crop sward structure within fields. Several farmland bird specialists that nest within arable crops have undergone marked population declines during recent periods of agricultural intensification. Understanding the mechanisms that link crop sward structure to demographic fitness and population change may be important for developing effective conservation solutions. We studied whole‐season breeding performance of a declining cereal crop specialist, the corn bunting Emberiza calandra, to test the relationships between crop sward structure and both nest site selection and reproductive output within intensively farmed landscapes. Experimental double‐drilling of cereal seed was used to manipulate crop sward structure and explain the observed within‐field nest distribution. The density of crop tillers (reproductive cereal stems) was a strong predictor of nest site selection and a disproportionate number of nests occurred close to (15–30 m) crop edges where regular seed sowing overlaps (operational double‐drilling) occurred during crop establishment. Nest survival was subject to a strong crop edge effect and re‐nesting rate increased with mean tiller density in the surrounding crop. Experimental double‐drilling that simulated seed sowing overlaps increased crop tiller density (by 25%) and corn bunting nest density (by 406%) compared to adjacent areas of operational double‐drilling. Corn buntings breeding in intensively managed cereal crops therefore place their nests in areas of high tiller density which under normal sowing practice tend to occur close to crop edges where nest survival is low. A simple population model indicated that productivity under conventional, intensive cereal management may be too low to sustain local populations in the absence of immigration. Modern cereal husbandry therefore creates an ecological trap for nesting corn buntings. Synthesis and applications. This study highlights a novel mechanism by which modern cereal crop management lowers the potential reproductive success of a conservation priority species nesting in intensively managed cereal crops. Unavoidable overlapping of cereal seed along crop headlands, close to crop edges, systematically produces patches of dense sward that attract nesting corn buntings. This creates an ecological trap because nests close to crop edges are subject to high predation rates, and this may be linked to the loss of arable weeds elsewhere within crops. When double‐drilled strips are intentionally provided adjacent to these areas, nesting preference switches to these strips, suggesting a potential conservation solution. Provision of mid‐field double‐drilled strips at least 100 m from crop edges, if similarly selected by nesting females, should raise nest survival rates and improve population trends. Such interventions are simple and cheap to implement, unlike most conservation measures in high‐value cropping systems.

Risk assessment of pesticide seed treatment for farmland birds using refined field data

Summary Due to reductions in winter food resources, newly sown cereal seeds have become a key component of many bird species' diets, but these seeds are often treated with pesticides that may cause toxic effects. To complete an appropriate risk assessment, data on treated seed toxicity need to be combined with information about the risk of exposure of birds in the field and the factors that modulate such exposure. We studied the abundance of pesticide‐treated seeds available for birds in the field, the pesticides and their concentrations in treated seeds, and the bird species observed in the field that were feeding on these pesticide‐treated seeds. The exposure of red‐legged partridge to treated winter cereal seeds was characterized through the analysis of crop and gizzard contents of hunted individuals (n = 189). Moreover, we measured the contribution of cereal seeds in the autumn–winter diet of partridges in order to assess the potential risk of exposure to pesticide‐treated seeds. Density of treated seeds on the soil surface after sowing (11·3 ± 1·2 seeds m−2 in the centre of field and 43·4 ± 5·5 seeds m−2 in the headlands) was enough to provide, in an area between 6 and 50 m2, doses of six active ingredients above those indicating acute (i.e. a dose capable of killing 50% of individuals of a sensitive species) and / or chronic (no observed effect level) toxicity. Up to 30 bird species were observed consuming treated cereal seeds in recently sown fields. Corn bunting was identified as an appropriate focal passerine species for the risk assessment of pesticide‐treated seeds. We found that treated seeds were an important route of pesticide ingestion for red‐legged partridge; pesticide residues (six fungicides and two insecticides) were found in 32·3% of crops and gizzards. Cereal seeds represented more than half (53·4 ± 4·3%) of total biomass consumed by partridges from October to February. Synthesis and applications. The field exposure data combined with previous studies about the toxicity to partridges of using pesticide‐treated seeds point to an unacceptable risk of this practice to farmland birds. Our results suggest that the prophylactic use of pesticide‐coated seeds should be avoided, with the approval of this treatment considered on a case‐by‐case basis and accompanied with specific measures to minimize risks of adverse effects on avian communities.