Importància dels guarets ambientals com a font d'insectes per a la conservació del sisó (Tetrax tetrax) i altres ocells esteparis en els secans cerealístics

Els sistemes agrícoles d'Europa occidental (entre els quals els secans cerealístics, amb una rica comunitat d'ocells esteparis greument amenaçada) han sofert una important intensificació que ha comportant fortes disminucions de les comunitats de plantes, d'ocells i d'insectes. Aquests darrers, sobretot els ortòpters, són la base de l'alimentació de molts ocells esteparis, fins i tot de polls d'espècies no insectívores, com el sisó (Tetrax tetrax). Tot i que els marges dels camps són un hàbitat clau com a font d'invertebrats i, en general, per a la conservació de la biodiversitat dels entorns conreats, poden ser insuficient per compensar la pèrdua d'hàbitat en el seu conjunt. La introducció de guarets ambientals dins de la matriu agrícola de cereal constitueix una eina útil per a la diversificació dels paisatges agraris excessivament homogenis. En el cas del sisó, poden proporcionar zones de cant, de nidificació i d'alimentació tant de polls com adults. Per revertir la negativa situació del sisó a Catalunya, a partir de l'any 2006 es van començar a implantar a la ZEPA Secans de Belianes-Preixana (entre altres) guarets ambientals, bé amb vegetació natural o bé sembrats amb alfals. Per avaluar els resultats de les actuacions realitzades, entre el 2010 i 2012 es va realitzar un total 140 censos d'ortòpters i lepidòpters en els diferents medis entre finals de juny-primers de juliol, quan hi ha els polls de sisó. Dels resultats es desprèn que els guarets ambientals presenten l'abundància més alta d'ortòpters i lepidòpters, seguits per les parcel·les amb ordi, els rostoll i finalment els llaurats. Així, els guarets ambientals, sobretot amb alfals, tenen de mitjana entre 2,5 i 4 vegades més ortòpters que els camps de cereal abans de la sega i entre 9 i 14 vegades més que els rostolls, essent els ortòpters pràcticament absents als llaurats. Un cas semblant, tot i que menys marcat, s'observa també en els lepidòpters. La precipitació de finals d'hivern–primavera sembla també un paràmetre important per explicar el nombre d'artròpodes dels diferents medis, sobretot dels guarets amb alfals. Per tot l'anterior, es considera que l'establiment de guarets ambientals és una pràctica clarament positiva per a les poblacions d'artròpodes, que pot afavorir també l'èxit reproductor del sisó i altres ocells esteparis en les àrees cerealistes intensificades.Farmland ecosystems of Western Europe (including the dryland cereal pseudo-steppes, with a rich and seriously endangered community of steppe birds) have undergone a great intensification process which has led to sharp decreases in the communities of plants, birds and insects. These, especially orthopterans, are the staple diet of many steppe birds, including some strictly herbivorous species whose chicks rely mainly on insects during their first weeks of live, such as the little bustard (Tetrax tetrax). Although field edges are key invertebrate source habitats, as well as for biodiversity conservation in general, they may not compensate for the loss and homogenization of landscape in intensified farmland. The introduction of wildlife fallows within the cereal matrix can be a very useful tool to diversify the landscape in excessively homogeneous areas. In the case of the little bustard, to provide display, nesting and feeding areas for adults and chicks. To reverse the negative situation of the little bustard in Catalonia, in 2006 a program was started in the SPA Belianes- Preixana (among others) to implement wildlife fallows, either with natural or sown with alfalfa. To evaluate the results of this actions, between 2010 and 2012 we conducted a total of 140 Orthoptera and Lepidoptera counts in different habitats in late June-early July, coinciding with the chick little bustard growing period. The results show that the wildlife fallows have the highest abundance of orthopterans and lepidopterans, followed by plots with barley stubble and, finally, plough fields. Thus, wildlife fallows, especially those sown with alfalfa, have on average between 2.5-4 times more orthopterans than unharvested cereal fields, between 9-14 times more than cereal stubble fields. Orthopterans are virtually absent from plough fields. A similar, though less marked, pattern is also observed in the lepidopterans. The amount of rain in late winterspring seems to be an important parameter to account for the number of arthropods in the different habitats, especially in the wildlife fallowsimwith alfalfa. To conclude with, we believe that the establishment of wildlife fallows is a positive management practice to promote arthropod populations in farmland, which can also have positive effects to improve the reproductive success of the little bustard and other steppe birds in areas intensified cereal

Impacte de la recuperació de l'estany d'Ivars i Vila-sana sobre la població d'ocells aquàtics hivernal a la plana de Lleida

L'estany d'Ivars i Vila-sana havia estat una de les principals zones humides de la Catalunya interior. La seva dessecació a principis dels anys 50 del segle passat va comportar la desaparició dels ocells aquàtics que hi habitaven . L'any 2006, després de més de 50 anys de la seva dessecació, es va posar en marxa el procés per a recuperar l'antic estany i es va començar a reinundar la seva cubeta. Per tal de valorar la resposta dels ocells aquàtics a la recuperació de l'estany s'han analitzat les dades dels censos d'ocells aquàtics hivernants de Catalunya Obtingudes a la plana de Lleida el període 2003-201

Black-shouldered Kite (Elanus caeruleus) diet in an area recently colonized in the north-east of Iberian Peninsula

S'ha estudiat la dieta de l'esparver d'espatlles negres en una zona colonitzada recentment a Catalunya. Els resultats es basen en l'anàlisi de 342 egagròpiles recollides després de la reproducció en quatre dels cinc nius coneguts a Catalunya entre 1998, 1999, 2003 i 2004. Es van identificar un total de 512 preses, totes elles petits vertebrats, principalment talpons i ratolins els quals van suposar entre un 64,4-30,3% del total de les preses consumides. El nombre de polls volanders es va correlacionar positivament amb el percentatge de talpons de la dieta, cosa que dóna suport al caràcter de l'esparver d'espatlles negres com un especialista de talpons al sud d'Europa

Landscape-scale effects of irrigation on a dry cereal farmland bird community

Landscape modification and habitat fragmentation are one of the major current threats to biodiversity. The main source of habitat fragmentation is the loss of focal habitat area, but changes in the composition of the surrounding landscape also have a direct effect on biodiversity. These changes may lead to the loss of some species but also may favor species replacement. Farmland birds in Europe are affected by landscape changes due to farmland intensification, such as the spread of irrigation, which may occur at different spatial scales. As irrigation is expected to increase in the coming years, which may affect protected areas, it is necessary to evaluate its potential consequences over focal biodiversity. In this study we assess the relationship between the increase of irrigated land at different spatial scales and changes in a dry cereal farmland bird community, bird abundance and species richness, using generalized linear models. We used a dry cereal farmland affinity index to describe the level of community specificity for dry cereal farmland. The increase in irrigated tree orchards produced an increase in species richness up to 500 m away from the irrigated area, which had a negative effect on the dry cereal farmland bird community, by triggering a replacement of specialist by generalist species. Our results show the importance of landscape-scale effects of irrigation occurring outside protected areas on the farmland bird community inside Natura 2000 sites, as well as how these effects are detected even at long distances from the disturbance source.Departament d’Agricultura, Ramaderia, Pesca i Alimentació and Infraestructures de la Generalitat de Catalunya S.A.U. have funded a relevant part of the field work and data acquisition

Passive acoustic monitoring for estimating human-wildlife conflicts: The case of bee-eaters and apiculture

In human-wildlife conflicts, it is crucial to develop accurate protocols for the reliable verification of the causative species and its relationship with potential damage claims. One of such conflicts is that occurring between apiarists and bee-eaters. In this work, we aim to assess the utility of passive acoustic monitoring (PAM) as an efficient methodology to measure European bee-eater (Merops apiaster) predation pressure at beehives and its impact on honeybees foraging activity. Using Autonomous Recording Units (ARUs) in apiaries, coupled to automated recognition methods for bee-eater calls identification, we found a positive relationship between Vocal Activity Rate (VAR) index and number of bee-eaters hunting attempts on honeybees. We also found that VAR varied over time, showing a lower predation pressure during midday hours and higher during the post-breeding migratory period. Honeybees flying activity was negatively associated with VAR and this relationship was conditioned by the hour of the day. Our study offers a new application of PAM and acoustic derived indices for the evaluation of potential damages caused by wildlife. We focused on the interaction between honeybees and the European bee-eater, but we expect PAM might be useful also to remotely monitor impacts to human activities produced by other vocally active species.European bee-eater monitoring was funded by the Department of Territory and Sustainability of the Generalitat de Catalunya. ARUs conception and design were partially supported by Programa de Investigación y Conservación del Zoo de Barcelona within the project ‘Nuevas tecnologías para viejos trabajos. Uso de grabadores automáticos para la detección y censo de especies raras y amenazadas. El caso de la alondra ricotí en Lleida y otras poblaciones pequeñas’. CPG acknowledges the support from Ministerio de Educación y Formación Profesional through the Beatriz Galindo Fellowship (Beatriz Galindo – Convocatoria 2020)

Low-cost open-source recorders and ready-to-use machine learning approaches provide effective monitoring of threatened species

Passive acoustic monitoring is a powerful tool for monitoring vocally active taxa. Automated signal recognition software reduces the expert time needed for recording analyses and allows researchers and managers to manage large acoustic datasets. The application of state-of-the-art techniques for automated identification, such as Convolutional Neural Networks, may be challenging for ecologists and managers without informatics or engineering expertise. Here, we evaluated the use of AudioMoth — a low-cost and open-source sound recorder — to monitor a threatened and patchily distributed species, the Eurasian bittern (Botaurus stellaris). Passive acoustic monitoring was carried out across 17 potential wetlands in north Spain. We also assessed the performance of BirdNET — an automated and freely available classifier able to identify over 3000 bird species — and Kaleidoscope Pro — a user-friendly recognition software — to detect the vocalizations and the presence of the target species. The percentage of presences and vocalizations of the Eurasian bittern automatically detected by BirdNET and Kaleidoscope software was compared to manual annotations of 205 recordings. The species was effectively recorded up to distances of 801–900 m, with at least 50% of the vocalizations uttered within that distance being manually detected; this distance was reduced to 601–700 m when considering the analyses carried out using Kaleidoscope. BirdNET detected the species in 59 of the 63 (93.7%) recordings with known presence of the species, while Kaleidoscope detected the bittern in 62 recordings (98.4%). At the vocalization level, BirdNet and Kaleidoscope were able to detect between 76 and 78%, respectively, of the vocalizations detected by a human observer. Our study highlights the ability of AudioMoth for detecting the bittern at large distances, which increases the potential of that technique for monitoring the species at large spatial scales. According to our results, a single AudioMoth could be useful for monitoring the species' presence in wetlands of up to 150 ha. Our study proves the utility of passive acoustic monitoring, coupled with BirdNet or Kaleidoscope Pro, as an accurate, repeatable, and cost-efficient method for monitoring the Eurasian bittern at large spatial and temporal scales. Nonetheless, further research should evaluate the performance of BirdNET on a larger number of species, and under different recording conditions (e.g., more closed habitats), to improve our knowledge about BirdNET's ability to perform bird monitoring. Future studies should also aim to develop an adequate protocol to perform effective passive acoustic monitoring of the Eurasian bittern.CPG acknowledges the support from the Ministerio de Educación y Formación Profesional through the Beatriz Galindo Fellowship (Beatriz Galindo – Convocatoria 2020)

Efficiency of species survey networks can be improved by integrating different monitoring approaches in a spatial prioritization design

Public participation to monitoring programs is increasingly advocated to overcome scarcity of resources and deliver important information for policy-making. Here, we illustrate the design of optimal monitoring networks for bird species of conservation concern in Catalonia (NE Spain), under different scenarios of combined governmental and citizen-science monitoring approaches. In our case study, current government efforts, limited to protected areas, were insufficient to cover the whole spectrum of target species and species-threat levels, reinforcing the assumption that citizen-science data can greatly assist in achieving monitoring targets. However, simply carrying out both government and citizen-science monitoring ad hoc led to inefficiency and duplication of efforts: some species were represented in excess of targets while several features were undersampled. Policy-making should concentrate on providing an adequate platform for coordination of government and public-participatory monitoring to minimize duplicated efforts, overcome the biases of each monitoring program and obtain the best from both

Inter‑individual consistency in habitat selection patterns and spatial range constraints of female little bustards during the non‑breeding season

Background: Identifying the factors that affect ranging behavior of animals is a central issue to ecology and an essential tool for designing effective conservation policies. This knowledge provides the information needed to pre- dict the consequences of land-use change on species habitat use, especially in areas subject to major habitat trans- formations, such as agricultural landscapes. We evaluate inter-individual variation relative to environmental predictors and spatial constraints in limiting ranging behavior of female little bustards (Tetrax tetrax) in the non-breeding season. Our analyses were based on 11 females tracked with GPS during 5 years in northeastern Spain. We conducted devi- ance partitioning analyses based on different sets of generalized linear mixed models constructed with environmen- tal variables and spatial filters obtained by eigenvector mapping, while controlling for temporal and inter-individual variation. Results: The occurrence probability of female little bustards in response to environmental variables and spatial filters within the non-breeding range exhibited inter-individual consistency. Pure spatial factors and joint spatial-habitat factors explained most of the variance in the models. Spatial predictors representing aggregation patterns at ~ 18 km and 3-5 km respectively had a high importance in female occurrence. However, pure habitat effects were also identi- fied. Terrain slope, alfalfa, corn stubble and irrigated cereal stubble availability were the variables that most contrib- uted to environmental models. Overall, models revealed a non-linear negative effect of slope and positive effects of intermediate values of alfalfa and corn stubble availability. High levels of cereal stubble in irrigated land and roads had also a positive effect on occurrence at the population level. Conclusions: Our results provide evidence that female little bustard ranging behavior was spatially constrained beyond environmental variables during the non-breeding season. This pattern may result from different not mutually exclusive processes, such as cost-benefit balances of animal movement, configurational heterogeneity of environ- ment or from high site fidelity and conspecific attraction. Measures aimed at keeping alfalfa availability and habitat heterogeneity in open landscapes and flat terrains, in safe places close to breeding grounds, could contribute to protect little bustard populations during the non-breeding season

Th e roles of environmental and geographic variables in explaining the diff erential wintering distribution of a migratory passerine in southern Europe

Abstract In birds, spatial segregation between age or sex categories during the non-breeding period is a common phenomenon. The main single-factor hypotheses that have been stated to explain this are: (1) body-size variations (that result in more or less cold tolerance) interact with local climate, which promotes age-or sex-associated distributional optima; (2) the dominant age or sex monopolizes high-quality areas; and (3) the age or sex overwintering closer to breeding quarters does so due to the benefits of earlier arrival at the breeding quarters. Southern European countries host millions of birds from northern Europe during the winter period each year. In this work, we aimed to determine the ultimate causes (geographic location and distance to obligate migratory pathways, temperature and land use as a surrogate for food availability) explaining spatial segregation of Reed Buntings (Emberiza schoeniclus) by age and sex in winter. We used data from 38 sampling points across Iberia during the winter of 2011-2012. Reed Bunting abundance did not fit any of our possible models better than the null model, so we were unable to predict bird numbers across Iberia. Moreover, males were found to be predominant at sites close to presumably obligate migratory pathways (western/eastern Pyrenees). Body mass was higher in first-year birds and males, and tended to increase with distance to obligate migratory pathways, land use (in particular with a decreasing proportion of open habitats and urban areas), increasing minimum temperature, and decreasing mean temperature. Our data suggest that the increase in the proportion of males close to obligate migratory pathways is associated with the advantage to males in wintering as close as possible to breeding quarters