Detecting management gaps for biodiversity conservation: An integrated assessment.

The latest report on the state of nature in Europe (2013-2018) shows that biodiversity is declining at an alarming rate, with most protected species and habitats in poor condition. Despite an increasing volume of collected biodiversity information, urgent action is needed to integrate biodiversity data and knowledge to improve conservation efforts. We conducted a study in Catalonia (NE Spain), where we collected management measures implemented between 2013 and 2018, including allocation, budget, pressures aimed, and habitats/species potentially benefiting. We integrated information on pressures and habitats/species with the measures to identify non-spatial management gaps. Then, we integrated the spatially explicit information to determine the spatial management gap, identifying geographical areas where species/habitats are under pressure without registered measures. We demonstrated the importance of integrating existing information. Our findings revealed that resources were often not distributed adequately across species/habitats, with biases towards certain taxa being a common issue. The non-spatial management gap analysis identified taxonomic groups, especially plants and mollusks with the wider management gaps. We also identified threatened areas, especially in the northeast of the region with the larger spatial management gaps. These results could guide priority objectives to optimize conservation efforts. Integrating different information sources provided a broader view of the challenges that conservation science is facing nowadays. Our study offers a path toward bending the curve of biodiversity loss by providing an integrative framework that could optimize the use of the available information and help narrow the knowing-doing gap. In the context of the EU, this example demonstrates how information can be used to promote some environmental policy instruments, such as the Prioritized Action Frameworks (PAFs). Additionally, our findings highlight the importance of supporting decision-making with systematic assessments to identify deficiencies in the conservation process, reduce the loss of critical ecosystems and species, and avoid biases among taxa.

Distance functions of carabids in crop fields depend on functional traits, crop type and adjacent habitat: a synthesis.

Natural pest and weed regulation are essential for agricultural production, but the spatial distribution of natural enemies within crop fields and its drivers are mostly unknown. Using 28 datasets comprising 1204 study sites across eight Western and Central European countries, we performed a quantitative synthesis of carabid richness, activity densities and functional traits in relation to field edges (i.e. distance functions). We show that distance functions of carabids strongly depend on carabid functional traits, crop type and, to a lesser extent, adjacent non-crop habitats. Richness of both carnivores and granivores, and activity densities of small and granivorous species decreased towards field interiors, whereas the densities of large species increased. We found strong distance decays in maize and vegetables whereas richness and densities remained more stable in cereals, oilseed crops and legumes. We conclude that carabid assemblages in agricultural landscapes are driven by the complex interplay of crop types, adjacent non-crop habitats and further landscape parameters with great potential for targeted agroecological management. In particular, our synthesis indicates that a higher edge-interior ratio can counter the distance decay of carabid richness per field and thus likely benefits natural pest and weed regulation, hence contributing to agricultural sustainability.

Hearing to the Unseen: AudioMoth and BirdNET as a Cheap and Easy Method for Monitoring Cryptic Bird Species.

The efficient analyses of sound recordings obtained through passive acoustic monitoring (PAM) might be challenging owing to the vast amount of data collected using such technique. The development of species-specific acoustic recognizers (e.g., through deep learning) may alleviate the time required for sound recordings but are often difficult to create. Here, we evaluate the effectiveness of BirdNET, a new machine learning tool freely available for automated recognition and acoustic data processing, for correctly identifying and detecting two cryptic forest bird species. BirdNET precision was high for both the Coal Tit (Peripatus ater) and the Short-toed Treecreeper (Certhia brachydactyla), with mean values of 92.6% and 87.8%, respectively. Using the default values, BirdNET successfully detected the Coal Tit and the Short-toed Treecreeper in 90.5% and 98.4% of the annotated recordings, respectively. We also tested the impact of variable confidence scores on BirdNET performance and estimated the optimal confidence score for each species. Vocal activity patterns of both species, obtained using PAM and BirdNET, reached their peak during the first two hours after sunrise. We hope that our study may encourage researchers and managers to utilize this user-friendly and ready-to-use software, thus contributing to advancements in acoustic sensing and environmental monitoring.

Age ratio, crippling losses and factors affecting daily hunting bags of European Turtle-dove in Spain: Implications for sustainable harvest management of a declining migratory species.

Knowledge of seasonal variation in hunting pressure and the demographic composition of hunting bags is likely to be important for the effective management of quarry species. Such knowledge is particularly important where regulatory mechanisms aim to avoid the over-exploitation of quarry species having unfavourable conservation status. We compiled information on the age composition of harvested European Turtle-doves (Streptopelia turtur), and the daily numbers of doves shot and retrieved from 68 hunting estates spread across four Spanish regions. We use these data to describe temporal variation, and identify factors affecting daily hunting bags, age composition and crippling losses. We found that more juvenile doves were hunted than adults (and more than expected in a stable population) especially at the beginning of the hunting season, suggesting greater vulnerability of juveniles to hunting. The number of doves hunted each day declined through the hunting season and increased with the number of hunters present. Crippling losses averaged 9.6 % of all doves shot; applying this rate to recent Spanish government hunting statistics suggests under-recording of approximately 90,000 doves annually for the entire country. Our data on age composition and crippling losses can serve as direct inputs into future models of sustainable harvest for Turtle Dove in Europe. Our results highlight the importance of improving knowledge about the variables influencing take at the hunting event level for designing more efficiency regulatory measures.

Protect European green agricultural policies for future food security.

European green agricultural policies have been relaxed to allow cultivation of fallow land to produce animal feed and meet shortfalls in exports from Ukraine and Russia. However, conversion of semi-natural habitats will disproportionately impact long term biodiversity and food security.

Metabarcoding insights into the diet and trophic diversity of six declining farmland birds.

Knowledge of feeding ecology of declining species, such as farmland birds, is essential to address their conservation requirements, especially when their habitats are suffering important reductions of trophic resources. In this study, we apply a metabarcoding approach to describe the diet composition of six of the most significant farmland birds inhabiting European cereal pseudo-steppes: little bustard, great bustard, pin-tailed sandgrouse, black-bellied sandgrouse, red-legged partridge, and common quail. We further studied seasonal diet variations (autumn to spring) in all species but the common quail, whose diet was studied during spring and summer. We show that study species´ diets mostly consisted of plants, although in the case of little bustard and great bustard arthropods are also highly relevant. Among arthropods, we found high proportions of thrips, arachnids, and springtails, which were previously unreported in their diet, and some taxa that could be used as antiparasitic food. Moreover, we report that little bustard's diet is the least rich of that of all studied species, and that diet of all these species is less diverse in winter than in autumn and spring. Diet composition of these declining species supports the importance of natural and semi-natural vegetation and landscape mosaics that can provide a wide variety of arthropods, plants, and seeds all year-round.

Increasing crop heterogeneity enhances multitrophic diversity across agricultural regions.

Agricultural landscape homogenization has detrimental effects on biodiversity and key ecosystem services. Increasing agricultural landscape heterogeneity by increasing seminatural cover can help to mitigate biodiversity loss. However, the amount of seminatural cover is generally low and difficult to increase in many intensively managed agricultural landscapes. We hypothesized that increasing the heterogeneity of the crop mosaic itself (hereafter "crop heterogeneity") can also have positive effects on biodiversity. In 8 contrasting regions of Europe and North America, we selected 435 landscapes along independent gradients of crop diversity and mean field size. Within each landscape, we selected 3 sampling sites in 1, 2, or 3 crop types. We sampled 7 taxa (plants, bees, butterflies, hoverflies, carabids, spiders, and birds) and calculated a synthetic index of multitrophic diversity at the landscape level. Increasing crop heterogeneity was more beneficial for multitrophic diversity than increasing seminatural cover. For instance, the effect of decreasing mean field size from 5 to 2.8 ha was as strong as the effect of increasing seminatural cover from 0.5 to 11%. Decreasing mean field size benefited multitrophic diversity even in the absence of seminatural vegetation between fields. Increasing the number of crop types sampled had a positive effect on landscape-level multitrophic diversity. However, the effect of increasing crop diversity in the landscape surrounding fields sampled depended on the amount of seminatural cover. Our study provides large-scale, multitrophic, cross-regional evidence that increasing crop heterogeneity can be an effective way to increase biodiversity in agricultural landscapes without taking land out of agricultural production.

Designing a network of green infrastructure to enhance the conservation value of protected areas and maintain ecosystem services.

There is a growing demand for holistic landscape planning to enhance sustainable use of ecosystem services (ESS) and maintenance of the biodiversity that supports them. In this context, the EU is developing policy to regulate the maintenance of ESS and enhance connectivity among protected areas (PAs). This is known as the network of Green Infrastructure (GI). However, there is not a working framework defined to plan the spatial design of such network of GI. Here, we use the software Marxan with Zones, to prioritize the spatial distribution of different management zones that accommodate the needs of a network of GI. These zones included a conservation zone, mainly devoted to protecting biodiversity, a GI zone, that aimed at connecting PAs and maintaining regulating and cultural ESS; and a management zone devoted to exploiting provisioning ESS. We performed four planning scenarios that distribute the targets for ESS and biodiversity in different ways across management zones. We also conducted a sensitivity analysis by increasing ESS targets to explore trade-offs that may occur when managing together biodiversity and ESS. We use Catalonia (northeastern Spain) as a case study. We found that the representation of ESS could be achieved for intermediate targets in all scenarios. There was, however, a threshold on these targets over which trade-offs appeared between maintaining regulating and cultural ESS and biodiversity versus getting access to provisioning ESS. These "thresholds values" were displaced towards higher ESS targets when we moved from more strict to more flexible planning scenarios (i.e., scenarios that allowed mixing representation of objectives for biodiversity and ESS within the same zone). This methodological approach could help design a framework to integrate biodiversity and ESS management in holistic plans and decision making and, at the same time, meeting European mandates concerning the design of GI networks, or similar needs elsewhere.

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 predict the consequences of land-use change on species habitat use, especially in areas subject to major habitat transformations, 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 deviance partitioning analyses based on different sets of generalized linear mixed models constructed with environmental 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 identified. Terrain slope, alfalfa, corn stubble and irrigated cereal stubble availability were the variables that most contributed 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 environment 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.

European population trends and current conservation status of an endangered steppe-bird species: the Dupont's lark Chersophilus duponti.

BACKGROUND: Steppe-birds face drastic population declines throughout Europe. The Dupont's lark Chersophilus duponti is an endangered steppe-bird species whose European distribution is restricted to Spain. This scarce passerine bird could be considered an 'umbrella species', since its population trends may reveal the conservation status of shrub-steppes. However, trends for the Spanish, and thus European, population of Dupont's lark are unknown. In this work, we evaluated Dupont's lark population trends in Europe employing the most recent and largest compiled database to date (92 populations over 12 years). In addition, we assessed the species threat category according to current applicable criteria (approved in March 2017) in the Spanish catalogue of threatened species (SCTS), which have never been applied to the Dupont's lark nor to any other Spanish species. Finally, we compared the resulting threat categories with the current conservation status at European, national and regional levels. METHODS: We fitted switching linear trend models (software TRIM-Trends and Indices for Monitoring data) to evaluate population trends at national and regional scale (i.e. per Autonomous Community) during the period 2004-2015. In addition, the average finite annual rate of change ( λ ¯ ) obtained from the TRIM analysis was employed to estimate the percentage of population size change in a 10-year period. A threat category was assigned following A1 and A2 criteria applicable in the SCTS. RESULTS: Trends showed an overall 3.9% annual decline rate for the Spanish population (moderate decline, following TRIM). Regional analyses showed high inter-regional variability. We forecasted a 32.8% average decline over the next 10 years. According to these results, the species should be listed as 'Vulnerable' at a national scale (SCTS). At the regional level, the conservation status of the species is of particular concern in Andalusia and Castile-Leon, where the species qualifies for listing as 'Endangered'. DISCUSSION: Our results highlight the concerning conservation status of the European Dupont's lark population, undergoing a 3.9% annual decline rate. Under this scenario, the implementation of a wide-ranging conservation plan is urgently needed and is vital to ensuring the conservation of this steppe-bird species. The role of administrations in matters of nature protection and the cataloguing of endangered species is crucial to reverse declining population trends of this and other endangered taxa.

Intraspecific and interspecific competition induces density-dependent habitat niche shifts in an endangered steppe bird.

Interspecific competition is a dominant force in animal communities that induces niche shifts in ecological and evolutionary time. If competition occurs, niche expansion can be expected when the competitor disappears because resources previously inaccessible due to competitive constraints can then be exploited (i.e., ecological release). Here, we aimed to determine the potential effects of interspecific competition between the little bustard (Tetrax tetrax) and the great bustard (Otis tarda) using a multidimensional niche approach with habitat distribution data. We explored whether the degree of niche overlap between the species was a density-dependent function of interspecific competition. We then looked for evidences of ecological release by comparing measures of niche breadth and position of the little bustard between allopatric and sympatric situations. Furthermore, we evaluated whether niche shifts could depend not only on the presence of great bustard but also on the density of little and great bustards. The habitat niches of these bustard species partially overlapped when co-occurring, but we found no relationship between degree of overlap and great bustard density. In the presence of the competitor, little bustard's niche was displaced toward increased use of the species' primary habitat. Little bustard's niche breadth decreased proportionally with great bustard density in sympatric sites, in consistence with theory. Overall, our results suggest that density-dependent variation in little bustard's niche is the outcome of interspecific competition with the great bustard. The use of computational tools like kernel density estimators to obtain multidimensional niches should bring novel insights on how species' ecological niches behave under the effects of interspecific competition in ecological communities.

A resource-based modelling framework to assess habitat suitability for steppe birds in semiarid Mediterranean agricultural systems.

European agriculture is undergoing widespread changes that are likely to have profound impacts on farmland biodiversity. The development of tools that allow an assessment of the potential biodiversity effects of different land-use alternatives before changes occur is fundamental to guiding management decisions. In this study, we develop a resource-based model framework to estimate habitat suitability for target species, according to simple information on species' key resource requirements (diet, foraging habitat and nesting site), and examine whether it can be used to link land-use and local species' distribution. We take as a study case four steppe bird species in a lowland area of the north-eastern Iberian Peninsula. We also compare the performance of our resource-based approach to that obtained through habitat-based models relating species' occurrence and land-cover variables. Further, we use our resource-based approach to predict the effects that change in farming systems can have on farmland bird habitat suitability and compare these predictions with those obtained using the habitat-based models. Habitat suitability estimates generated by our resource-based models performed similarly (and better for one study species) than habitat based-models when predicting current species distribution. Moderate prediction success was achieved for three out of four species considered by resource-based models and for two of four by habitat-based models. Although, there is potential for improving the performance of resource-based models, they provide a structure for using available knowledge of the functional links between agricultural practices, provision of key resources and the response of organisms to predict potential effects of changing land-uses in a variety of context or the impacts of changes such as altered management practices that are not easily incorporated into habitat-based models.

Ranging behaviour of little bustard males, Tetrax tetrax, in the lekking grounds.

We investigated the ranging behaviour during the breeding season of 18 radiotracked little bustard (Tetrax tetrax) males, a disperse-lekking species inhabiting the cereal pseudo-steppes. The average kernel 95% home range was 60±50 ha and the average cluster 85% area was 17±17 ha. Range structure was as relevant as home range size for explaining the variation in the ranging behaviour of males, which could be partially explained by age, habitat quality and site. Ranging behaviour varied from males defending small and concentrated home ranges with high habitat quality, to males holding larger home ranges composed by several arenas. Our results suggest that social dominance and resource availability may affect ranging behaviour of males during the breeding season. Also, mating systems constraints may play a role on the use of space of males within the lekking ground. The ranging behaviour of a given male may be determined by a tendency to reduce and concentrate the home range as age and social status increase, and several fine-tuning mechanisms adjusting the ranging behaviour to the prevailing environmental or social factors on a given site and year.

Capture myopathy in little bustards after trapping and marking.

Four little bustards (Tetrax tetrax) (one adult and three juvenile males), captured with leg nooses and fitted with a backpack radiotag, died after capture. The first bird was found after 16 days with its left foot caught in the harness and died after 1 day. The other birds showed symptoms of capture myopathy after release, such as the difficulty or inability to fly and/or walk. They died after 5, 6, and 8 days, respectively. At necropsy, muscles affected in all cases were those from the legs, and these were diffusely pale and dull, with a soft friable texture. Microscopically these muscles had multiple foci of myofiber fragmentation, loss of striation, and necrosis; a mononuclear cell infiltrate was observed in muscle from two birds. These findings suggest the little bustard is susceptible to capture myopathy and that caution should be exercised during its capture and handling.