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Intensive forest management has caused a decline in the numbers of birds specialized on old growth. Understanding how forest stand attributes influence the distribution of these specialists has hence become a prerequisite for sustainable forest management. In this study, we evaluated the conservation value of managed forests for old-growth forest specialists using the poorly studied Semi-collared Flycatcher as an example. We applied a boosted generalized additive model to identify forest characteristics that determine the occurrence of the bird in Bulgaria. We found that on a national scale, forest stand age and percent cover of broad-leaved forests best explain the breeding distribution of the flycatcher. Although, forest stands became suitable habitat at an age of around 70 years for this species, stands in the interior forest featuring trees older than 160 years and composed of more than 80% broad-leaved trees were preferred by the species. At a local scale, the amount of dead wood positively influenced nest site choice of the flycatcher. In total, 22.3% of all studied broad-leaved forests in Bulgaria showed a predicted habitat suitability higher than 50%. High-stem forests that are old enough to develop old-growth characteristics had the highest potential to serve as habitat for the Semi-collared Flycatcher in Bulgaria. Therefore, we conclude that a decrease in logging of forests stands older than 160 years decreases the risk of decline of the Semi-collared Flycatcher.

As more and more species become threatened, the need to assess population sizes accurately in order to facilitate effective management actions increases. There is an extensive literature on counting birds, but no consensus on the most appropriate units in which to record the results. To stimulate discussion on the use of “number of pairs” for estimating bird population size we review some of the main problems and difficulties. Some counts, especially of seabirds, give total numbers, whereas breeding season counts of songbirds often record territories or, less frequently, numbers of nests. The use of different units complicates comparisons, for example between non-breeding and breeding populations. In many populations there are non-breeding individuals (including immatures, helpers or those who have failed to secure a mate or a territory) that may be hard to distinguish from those that are breeding. Some of the last may even be more conspicuous than paired birds. The proportion of such, for most s...

Understanding the rules of habitat selection and the individual behavioural routines in the home-range is crucial for developing evidence-based conservation action. We investigated habitat selection and range use of adult little owls Athene noctua in relation to landscape configuration, habitat structure and resource distribution. We determined the preference of habitat structures by VHF-telemetry. Large- and fine-scale distribution patterns of voles – the main prey during the breeding season – were assessed by transect counts of signs of vole presence. An experiment using artificial perches was carried out to determine the fine-scale adjustment of the owls' range use in relation to prey abundance and vegetation height. Habitat selection and resource exploitation by little owls were structured at all spatial levels: (1) at the landscape scale, orchards were highly preferred over other areas. This accords with the patchy large-scale occurrence of voles, which were absent in cropland, but abundant in orchards and grassland; (2) within home-ranges, the spatial distribution of voles was highly inhomogeneous and structures with high prey abundance were used over-proportionally; (3) at the scale of foraging sites, little owls preferred patches with low vegetation over those with high prey abundance, establishing that prey availability is the crux. The results suggest that all levels of habitat selection and range use were related to farming practices and affected by current cultivation. Conservation measures should focus on the conservation and restoration of orchards on the landscape level and habitat management measures should focus on grasslands – the main food providers – by creating a mosaic of patches with short grass and tall grass. Together with other habitat structures providing food resources such as field edges, wildflower areas and structures facilitating access to prey, the quality of habitat patches in terms of food availability may be highly improved.

Within the European Union, national approaches of a ‘High Nature Value (HNV) farmland’ indicator have been developed to inform about the potential of agricultural landscapes to maintain biodiversity. We assessed how bird species abundance, richness and community composition, particularly of specialist species, were associated with the German HNV farmland indicator as an area-based aggregate and with its particular components which were semi-natural landscape elements and agricultural patches with characteristic plant species mapped in representative sample plots. The aggregated HNV indicator score showed a weak but positive relationship with generalist bird species only, while specialist species were associated with individual HNV farmland features characterizing wet grasslands and open farmland. Bird community analysis revealed three groups of HNV farmland features representative of particular landscape types: (1) complex landscapes with vertical woody structures such as hedgerows or small woodlands, (2) wet grasslands and (3) open agricultural land of low land-use intensity. Large portions of unexplained variance, however, indicated that the small-scaled HNV farmland features recorded without considering the landscape context may not have fully captured all important drivers of bird diversity in agricultural landscapes. To achieve a better representation of habitat requirements particularly of specialist bird species we propose surveying HNV farmland in a landscape context and calculating landscape-specific scores for highly structured, wetland-dominated and open landscapes of low land-use intensity. As compared to the aggregated indicator, the small-scale HNV farmland survey data would more efficiently enfold its potential for tailoring conservation schemes specifically to a given landscape type and its associated bird species.

Producing energy crops as an alternative to fossil fuels in order to reduce CO2 emissions will lead to large-scale changes in agricultural landscapes. Here, we quantify the potential impact of an increase in maize fields on the diversity of farmland birds by means of high resolution (25 9 25 m) land-use scenarios. We generated scenarios in which the area of maize production in Germany increases from presently 2.6 to 2.9, 3.6 and 4.3 million ha, corresponding to the energy crop production targets of the German Renewable Energy Act for the years 2020, 2035 and 2050. To test the mitigating potential of conservation measures, each scenario was generated in a standard version and a landscape protection version, with the latter excluding valuable farmland areas from being converted into maize fields. Nine species of farmland birds belonging to the governmental indicator scheme for sustainable land-use in Germany were modelled for the six nation-wide scenarios. The models predicted that only the Northern Lapwing and the Little Owl might profit from extended maize production. Despite this, the total number of breeding pairs of the indicator species was predicted to decline by about 0.4 million breeding pairs in the most intensive scenario. Protection of valuable farmland did not mitigate these negative effects in the models. Our findings suggest that increased production of energy crops conflicts with conservation of biological diversity.

Central Europe has the responsibility to protect the Red Kite Milvus milvus as it holds the majority (>50 % of all breeding pairs) of the global population. This entails the need for comprehensive knowledge of the birds’ ecology and distribution. Currently, only little is known about the factors limiting both the global occurrence of the Red Kite and its distribution on regional scales. In this study we analysed the effect of land use on the breeding distribution of Red Kites throughout Germany, the species’ core distribution area, using a distribution model. For the first time, an extensive data set was used for modelling comprising a sample size of 2,625 Red Kite breeding sites, high-resolution land-use data (10 m × 10 m) and climatic as well as topographic variables. The model revealed a strong relationship between land-use patterns and the Red Kite’s distribution. Furthermore, a comparison of the predicted habitat suitability map with the actual distribution of Red Kites showed that not all suitable habitats were occupied by the species and thus, the species’ distribution seems not to be in equilibrium with its environment. The differences between actual and predicted distribution may stem from present or former high mortality rates which are not compensated for by current reproduction rates. Additionally, low juvenile dispersal of Red Kites reduces recolonisation of unoccupied patches.

The use of artificial nest boxes to bolster populations of endangered cavity-nesting birds has increased significantly, but spatial variation of nest-box occupancy rates and breeding success within a nest-box population has been little studied. In a case study with 798 Little Owl (Athene noctua) nest boxes established in central Germany, we analyzed the dependence of occupancy rate and breeding success on the characteristics of the surrounding habitat. The analysis focused on two aspects of general concern for nest-box management: (1) whether nest boxes were occupied for breeding or were left unoccupied, and (2) whether Little Owls had different reproductive rates, depending on the location of nest boxes. A high resolution (1 × 1 m) land-use map was used to analyze species-habitat relationships, and Generalized Linear Mixed Models were used to predict suitable nest-box locations. During the period from 2004 to 2006, 544 (68%) of the nest boxes were never occupied, 144 (18%) housed birds with low ...

Distance sampling (DS) and territory mapping (TM) are globally applied bird survey techniques. However, specifically designed studies comparing results of both methods in different habitats in the framework of a scientific experiment have rarely been conducted. To provide a more generalized guidance for the field surveyor, here we evaluated estimates of bird abundances and number of bird species in four different habitats (broad-leaved forest, coniferous forest, open woodland and farmland) in central Germany. Abundances were estimated in parallel by TM and DS in 2006 and 2008, following standard protocols. Detection probability differed significantly among habitats and species. Density estimates by DS were in total 24% lower than those estimated by standardized TM. While the number of bird species detected with both methods was approximately the same, the estimated abundances of 15 bird species showed significant differences. Increasing the number from two to four and five registrations to count a territory by using TM decreased the density on average about 28 and 42%, respectively. Using standardized TM resulted in an overestimation of abundances of species showing a high detection probability. In contrast, DS estimated very high densities for species that had a very low detection probability. In fact, a highly negative correlation was found between the density estimated by DS and the detection probability. Using standardized TM and setting a fixed number of registrations before a location qualifies for a bird territory cannot compensate for the large differences in species detectability. Instead, the number of registrations required to count a territory should be adjusted to differences in detection probabilities and seasonal activity. From our results we can recommend a mean of four registrations if eight visits were conducted to count a territory. However, the lack of any statistically-based quality assessment reduces the serious usability of TM for estimating densities for science-based management application, whereas, the clear advantage of DS is that it provides error estimates and considers differences in species detectability.

For a large number of threatened bird species, no information on habitat requirements or population estimates are available. We show for one of the least-studied African birds, the Oberlander's Ground-Thrush Zoothera oberlaenderi, how a first assessment of its habitat preferences and population size can be done if a short-term census is combined with a GIS-based species–habitat analysis. Between 9 February and 14 March 2008, we made intensive field surveys, using point counts and mist-netting in Semliki and Bwindi Impenetrable National Parks (BINP), two forests in Uganda from which there are previous records. While the species was not recorded in Semliki, eight were heard singing in BINP. We made the first analysis of this species’ habitat preferences by analysing all records of the species with variables extracted from GIS layers for the BINP. It preferred dense forest types, close to rivers and at elevations of 1 500–1 935 m. Using detailed habitat information we calculated 30 km2 of suitable habitat (o...

Biodiversity on farmland is declining due to agricultural intensification and occurs across many taxa such as plants, insects or birds. Here, we modelled population sizes of five farmland birds in central Germany as the German Sustainability Indicator for Species Diversity (SISD) is based on this taxon. We explored options for sustainable farmland management by generating land-use scenarios at the regional scale. For individual bird species, high SISD scores could be reached by changing environmental variables, such as landscape or crop diversity, percent cover of spring cereals or hedge density. However, contrasting species responses to these variables prevented from reaching high scores for all species simultaneously. We were able to improve the total SISD score from 0.77 at present to 0.94 by increasing landscape and crop diversity or to 0.87 by increasing hedge density and reducing spring cereals, respectively. An economic evaluation of the return losses associated with these changes revealed that annual costs of approx. 5.5 €/ha farmland would suffice for this latter increase by optimizing hedges and spring cereals towards high SISD. We conclude that balancing three levels of trade-offs, i.e. contrasting requirements of species, diverging responses in different landscapes, and alternative economic options, is difficult to achieve without systematic modelling. Yet, by accounting for differences in landscape structure and species distributions at a regional spatial scale and by focusing on clearly defined measures such as hedge density or the cover of spring cereals rather than composite indices like landscape or crop diversity it seems possible to develop realisable, affordable and sustainable management strategies.

The Caucasian black grouse (CBG) is classified as “data deficient” by the IUCN. Lack of information to guide conservation measures is mainly due to the bird’s elusive behaviour for much of the year and to its remote distribution at higher altitudes of the Caucasus Mountains. In order to fill some of the knowledge gaps, we mapped potential suitable habitat across the Turkish part of the Lesser Caucasus using a spatial regression model, and estimated the total CBG population from alternative assumptions on population density and habitat separation. The CBG model was derived from 167 CBG records obtained during a survey in representative areas of the Turkish Caucasus, in conjunction with a supervised habitat classification of satellite images and with topographic parameters calculated from a digital elevation model. In total, approx. 5,000 km2 of suitable habitat were predicted to exist within the borders of Turkey, including areas where the CBG has not previously been searched for. Under conservative assumptions, this area can carry more than 4,800 individuals, which is higher than previously estimated. The predicted distribution map can be used to select priority areas for conservation and to specify additional survey locations of the species in areas, which so far have been less well sampled.

The Serengeti–Mara ecosystem holds one of the largest natural grasslands of the world, which is well known for its large herds of mammals. However, the bird community structure of these grasslands has hardly ever been studied. For the first time, a large-scale study on grassland bird communities has been conducted in all typical open grasslands of the Serengeti National Park. We used ten grassland plots representing a gradient of increasing vegetation height and also including shrubs and trees to analyse the influence of vegetation structure on the composition of grassland bird communities. Three communities of breeding birds were identified in relation to (a) short grass, (b) intermediate and long grass and (c) wooded grasslands. The bird communities of intermediate, long and wooded grassland were very similar, because of identical dominant bird species. Our results suggest that breeding birds of East African grasslands exhibit two contrasting habitat relationships: (1) birds that are restricted to short grass, and (2) species that are tolerant to vegetational shifts from intermediate grass via long grass to early stages of woody vegetation. Because the vegetation is often driven beyond this range in managed tropical grasslands through high grazing pressure or through shrub encroachment, we expect that the long-grass bird communities will not generally resist anthropogenic disturbance. Resume L’ecosysteme Mara-Serengeti contient une des plus vastes prairies naturelles du monde, bien connue pour ses importantes populations de mammiferes. Cependant, la structure de la communaute aviaire a a peine eteetudiee. Pour la premiere fois, une etude a grande echelle a ete realisee sur les communautes d'oiseaux des savanes herbeuses dans toutes les prairies ouvertes typiques du Parc National de Serengeti. Nous avons delimite 10 plots de prairies representant un gradient de hauteur de vegetation croissant et comprenant aussi des arbustes et des arbres, afin d'analyser l'influence de la structure de la vegetation sur la composition des communautes aviaires en savane herbeuse. On a identifie trois communautes d'oiseaux reproducteurs liees (a) a l'herbe rase, (b) a l'herbe intermediaire ou haute et (c) a la savane arboree. Les communautes d'oiseaux des herbes intermediaires, hautes et arborees etaient tres semblables en raison de l'espece d'oiseau dominante identique dans les deux milieux. Nos resultats laissent penser que les oiseaux reproducteurs des prairies est-africaines presentent deux types contrastes de relation avec leur habitat: (1) les oiseaux qui se limitent aux herbes courtes et (2) les especes qui tolerent des changements de vegetation entre herbes intermediaires et hautes et les stades precoces de vegetation ligneuse. Comme la vegetation evolue souvent au-dela de cet etat dans les prairies tropicales gerees qui connaissent un pâturage intense ou l'envahissement des buissons, nous nous attendons a ce que les communautes qui vivent dans les hautes herbes ne resistent generalement pas aux perturbations d'origine humaine.

Agricultural management is a major factor driving the change of faunal richness in anthropogenic landscapes. Thus, there is an urgent need to develop tools that allow decision-makers to understand better intended and unintended effects of agricultural policy measures on biodiversity. Here we demonstrate the potential of such a tool by combining a socio-economic model with the biodiversity model GEPARD to forecast the response of bird and carabid species richness to two scenarios of agricultural subsidies: (1) subsidies based on production levels and prices and (2) direct income support that is independent of production levels. We focussed on farmland of the Lahn-Dill area, Germany, as an example of European regions with low intensity farming. GEPARD predicts faunal richness and is based on multi-scaled resource-selection functions. Under both scenarios the area of predicted losses in species richness of birds and carabids was larger than the area of predicted gains in species richness. However, the area with predicted losses of avian richness was smaller under the direct income support scenario than under the production-based subsidy scenario, whereas the area with predicted losses of carabid species richness was smaller under the production-based subsidy scenario than under the direct income support. Yet locally, richness gains of up to four species were predicted for carabids under both scenarios. We conclude that the sometimes contrasting and heterogeneous responses of birds and carabids at different localities suggest the need for spatially targeted subsidy schemes. With the help of the GIS-based approach presented in this study, prediction maps on potential changes in local and regional species richness can be easily generated.

International audience; Key messageWe forecasted the effects of climate change and forest conversion options on common forest bird species by employing nation-wide high-resolution models. The results give details on how, where, and for which species forest conversion can mitigate climate change effects.Context To mitigate effects of climate change on forests, alterations are required to convert forests into less vulnerable forest types. Coniferous forest that has been cultivated extensively outside its natural range has been identified as being more vulnerable to climate change effects than deciduous forest.Aims The aim is to evaluate the effect of climate change mitigation measures on biodiversity due to forest conversion.MethodsWe generated five forest scenarios for Germany in which we systematically replaced coniferous with deciduous forest types. We forecasted the effects of climate change and forest conversion options on 25 forest bird species by employing high-resolution models to predict their current and future ranges and population size.Results Our simulations and modeling approach clearly predicted that climate change has a stronger impact on populations compared to distribution areas of common forest bird species. Forest conversion was predicted to amplify (15 species) and to weaken (10 species) the predicted gains and losses of species’ population size due to climate change. Using the total bird population size to evaluate the mitigation effect of the different forest scenarios, forest conversion below an elevation of 500 m a.s.l. was predicted to mitigate climate change effects by 0.3 million breeding pairs (−10 %). The relatively weak mitigation effect was mainly due to few generalist species that inhabit coniferous forests in large abundances and did not profit from a conversion to deciduous forests. Conclusion The results of the study give details on how, where, and for which species forest conversion can mitigate the anticipated effects of climate change.

There is a strong need to assess impacts on wildlife and their habitats before they occur, and to act proactively to avoid “costs” (e.g., loss of species, wilderness, ecological ­services, human lives or money; see Nielsen et al. 2008 for an applied example). Although the concept of being proactive has been known for decades, the global climate change discussion has brought these concepts to the forefront. Proactive action also has use in impact studies of stochastic catastrophes such as floods or hurricanes. Simulations and predictions across time can help to mitigate or even resolve current problems (Fig. 10.1). Such techniques are widely used to assess risks and they have evolved into industrial standards elsewhere, such as in operations research (Fuller et al. 2008), within the pharmaceutical, insurance, and car industries, and in public health (Herrick et al. in press). Weather forecasts have already shown the value and power of such models, ­driving many day-to-day decisions.

Windstorms, bark beetle outbreaks and fires are important natural disturbances in coniferous forests worldwide. Wind-thrown trees promote biodiversity and restoration within production forests, but also cause large economic losses due to bark beetle infestation and accelerated fungal decomposition. Such damaged trees are often removed by salvage logging, which leads to decreased biodiversity and thus increasingly evokes discussions between economists and ecologists about appropriate strategies. To reveal the reasons behind species loss after salvage logging, we used a functional approach based on four habitat-related ecological traits and focused on saproxylic beetles. We predicted that salvage logging would decrease functional diversity (measured as effect sizes of mean pairwise distances using null models) as well as mean values of beetle body size, wood diameter niche and canopy cover niche, but would increase decay stage niche. As expected, salvage logging caused a decrease in species richness, but led to an increase in functional diversity by altering the species composition from habitat-filtered assemblages toward random assemblages. Even though salvage logging removes tree trunks, the most negative effects were found for small and heliophilous species and for species specialized on wood of small diameter. Our results suggested that salvage logging disrupts the natural assembly process on windthrown trees and that negative ecological impacts are caused more by microclimate alteration of the dead-wood objects than by loss of resource amount. These insights underline the power of functional approaches to detect ecosystem responses to anthropogenic disturbance and form a basis for management decisions in conservation. To mitigate negative effects on saproxylic beetle diversity after windthrows, we recommend preserving single windthrown trees or at least their tops with exposed branches during salvage logging. Such an extension of the green-tree retention approach to windthrown trees will preserve natural succession and associated communities of disturbed spruce forests.

Intensive agriculture has had multiple negative effects on the environment across large areas of Europe, including a decrease in the degree to which these landscapes serve multiple functions. A quantitative evaluation of the deficits in landscape multifunctionality is difficult, however, for a given landscape as long as "multifunctional reference landscapes" are lacking. We present an interdisciplinary normative scenario approach to overcome this obstacle. Given the example of the lower Wetter-catchment in the Wetterau region (Hesse, Germany), we compare the existing landscape with an expert-generated multifunctional landscape scenario that may also serve as an alternative future. This approach may inspire policy makers and land users by providing a methodology for the design of alternative multifunctional futures in five steps: (1) documentation of today's landscape structure and land use at the scale of uniformly managed land units; (2) detection of functional deficits of today's landscape considering environmental (soil contamination, groundwater production, water quality, biodiversity), economic (land rent), and societal (landscape perception by its population) attributes; (3) compilation of a catalogue of alternative land uses (including linear landscape elements) suitable to minimize the detected functional deficits; (4) rule-based modification of today's land-use pattern into a normative scenario; and (5) comparison of today's landscape and the normative scenario by applying the model network ITE²M. Results highlight a strongly unbalanced allocation of private and public goods in today's landscape with severe deficits in environmental and societal landscape features, but a significantly higher land rent. The designed multifunctional scenario, instead, may be preferred by the local population, and their willingness to pay for multifunctionality could potentially compensate calculated opportunity costs. Hence, the generated landscape scenario may be regarded as an alternative, multifunctional future.

In this study we assess possible benefits of using satellite sensor data in large-scale landscape ecology. The study was conducted on the Serengeti Plains, Tanzania, combining (1) records from a bird survey, (2) local measurements of vegetation structure and precipitation, and (3) a habitat map derived from a Landsat satellite image classification. The question of whether ground-based or satellite data explained more of the species-environment relationships was explored by means of multivariate regression. On average across all 62 bird species recorded, the combination of satellite-based and groundbased data improved explained variance (R 2 = 0.26), as compared to satellite sensor data, or ground-based data alone (R 2 = 0.18 and 0.21, respectively). In spite of this low level of explained variance in the regressions, a classification of bird species according to utilised parameter space yielded reasonable results. Satellite image data seem to be suited to this kind of investigation. Ostrich 2007, 78(2): 259–263

High resolution remote sensing data facilitate the use of small-scale habitat features such as trees or hedges in the analysis of species–habitat relationships. Such data potentially enable more accurate species–habitat mapping than lower resolution data. Here, for the first time, we systematically investigated this hypothesis by altering the spatial resolution from 1 m up to 1000 m grain size in species–habitat models of 13 bird species. The study area covered the Nidda river catchment in central Germany, a large heterogeneous landscape of 1620 km 2 . A high resolution habitat map of the area was converted to coarser spatial and thematic resolutions in seven steps. We investigated how model performance responded to grain size, and we compared the differential effects of spatial resolution and thematic resolution on model performance. Explained deviance ( D 2 ) of the bird models generally decreased with coarser spatial resolution of the data, although it did not decrease monotonically in all species. On average across all species, model D 2 decreased from 41.5 at 1 m grain size to 15.9 at 1000 m grain size. Ten species were best modelled at 1 m, two species at 3 m and one species at 32 m grain size. Model performance degraded continuously with increasing grain size, both in habitat generalist and habitat specialist bird species, and was systematically lower in habitat generalists. The higher model performance observed at finer grain sizes was most likely caused by the combination of three factors: (1) high spatial accuracy of bird records and (2) a more precise location and delineation of habitat features and, (3) to a lesser degree, by more habitat types differentiated in maps of finer resolution. We conclude that higher spatial and thematic resolution data can be essential for deriving accurate predictions on bird distribution patterns from species–habitat models. Especially for bird species that are sensitive to specific land-use types or to small-scaled habitat features, a grain size of 1–3 m seems most promising.