A review and meta-analysis of the effects of climate change on Holarctic mountain and upland bird populations

Mountain regions are globally important areas for biodiversity but are subject to multiple human-induced threats, including climate change, which has been more severe at higher elevations. We reviewed evidence for impacts of climate change on Holarctic mountain bird populations in terms of physiology, phenology, trophic interactions, demography and observed and projected distribution shifts, including effects of other factors that interact with climate change. We developed an objective classification of high-elevation, mountain specialist and generalist species, based on the proportion oftheir breeding range occurring in mountain regions. Our review found evidence of responses of mountain bird populations to climate (extreme weather events, temperature, rainfall and snow) and environmental (i.e. land use) change, but we know little about either the underlying mechanisms or the synergistic effects of climate and land use. Long-term studies assessing reproductive success or survival of mountain birds in relation to climate change were rare. Few studies have considered shifts in elevational distribution over time and a meta-analysis did not find a consistent direction in elevation change. A meta-analysis carried out on future projections of distribution shifts suggested that birds whose breeding distributions are largely restricted to mountains are likely to be more negatively impacted than other species. Adaptation responses to climate change rely mostly on managing and extending current protected areas for both species already present, and for expected colonizing species that are losing habitat and climate space at lower elevation. However, developing effective management actions requires an improvement in the current knowledge of mountain species ecology, in the quality of climate data and in understanding the role of interacting factors. Furthermore, the evidence was mostly based on widespread species rather than mountain specialists. Scientists should provide valuable tools to assess the status of mountain birds, for example through the development of a mountain bird population index, and policy-makers should influence legislation to develop efficient agri-environment schemes and forestry practices for mountain birds, as well as to regulate leisure activities at higher elevations.Peer reviewe

New vineyard cultivation practices create patchy ground vegetation, favouring Woodlarks

Intensive agriculture, in which detrimental farming practices lessen food abundance and/or reduce food accessibility for many animal species, has led to a widespread collapse of farmland biodiversity. Vineyards in central and southern Europe are intensively cultivated; though they may still harbour several rare plant and animal species, they remain little studied. Over the past decades, there has been a considerable reduction in the application of insecticides in wine production, with a progressive shift to biological control (integrated production) and, to a lesser extent, organic production. Spraying of herbicides has also diminished, which has led to more vegetation cover on the ground, although most vineyards remain bare, especially in southern Europe. The effects of these potentially positive environmental trends upon biodiversity remain mostly unknown as regards vertebrates. The Woodlark (Lullula arborea) is an endangered, short-distance migratory bird that forages and breeds on the ground. In southern Switzerland (Valais), it occurs mostly in vineyards. We used radiotracking and mixed effects logistic regression models to assess Woodlark response to modern vineyard farming practices, study factors driving foraging micro-habitat selection, and determine optimal habitat profile to inform management. The presence of ground vegetation cover was the main factor dictating the selection of foraging locations, with an optimum around 55% at the foraging patch scale. These conditions are met in integrated production vineyards, but only when grass is tolerated on part of the ground surface, which is the case on ca. 5% of the total Valais vineyard area. In contrast, conventionally managed vineyards covering a parts per thousand yen95% of the vineyard area are too bare because of systematic application of herbicides all over the ground, whilst the rare organic vineyards usually have a too-dense sward. The optimal mosaic with ca. 50% ground vegetation cover is currently achieved in integrated production vineyards where herbicide is applied every second row. In organic production, ca. 50% ground vegetation cover should be promoted, which requires regular mechanical removal of ground vegetation. These measures are likely to benefit general biodiversity in vineyards

Unravelling migration connectivity reveals unsustainable hunting of the declining ortolan bunting

In France, illegal hunting of the endangered ortolan bunting Emberiza hortulana has been defended for the sake of tradition and gastronomy. Hunters argued that ortolan buntings trapped in southwest France originate from large and stable populations across the whole of Europe. Yet, the European Commission referred France to the Court of Justice of the European Union (EU) in December 2016 for infringements to legislation (IP/16/4213). To better assess the impact of hunting in France, we combined Pan-European data from archival light loggers, stable isotopes, and genetics to determine the migration strategy of the species across continents. Ortolan buntings migrating through France come from northern and western populations, which are small, fragmented and declining. Population viability modeling further revealed that harvesting in southwest France is far from sustainable and increases extinction risk. These results provide the sufficient scientific evidence for justifying the ban on ortolan harvesting in France.Peer reviewe

Addressing ecological light pollution at a national scale.

Natural sources of lighting are a major environmental cue that help structure ecological systems, yet these are undermined by artificial lighting which disrupts key processes such as migration, pollination and reproduction. Despite knowledge of diverse impacts and a huge shift towards LED street lighting, conservation practitioners are struggling to respond. We present key findings from a research collaboration between the University of Bern and the Swiss Federal office for the Environment, which aimed to identify practical ways to reduce the ecological impacts of artificial lighting. This project involved a review of the data available on Swiss lighting, a review of the known impacts of artificial lighting on national priority species, and spatial modelling to identify particularly light-sensitive locations. Undertaking such an analysis at a national level had the advantage of bringing the data and research gaps into sharp perspective. We found that in practice, the data used by local governments to manage lighting is typically a database of lamp locations, which also includes entries for lamp type, wattage and height. No national lamp inventory exists, and records for all private sources of lighting (associated with hospitals, commercial and industrial areas) are missing. Other sources of information such as VIIRS satellite data are occasionally used, but only as a broad emission indicator. Some attempts have been made at aerial night photography, but images remain uncalibrated and therefore useful primarily as indicators of bright lighting locations. Nothing is known about the impacts of artificial lighting on the majority of species identified as priorities for nature conservation in Switzerland. Bats are the most well studied group, followed by birds. What was striking was the focus of studies on species reactions to individual point sources of light. In many cases, no information was provided on lamp type, height, luminous flux, wattage, or proximity to the ecological receptor. This is a serious deficiency, as practitioners will inevitably struggle to apply these research results, to identify which locations should be prioritised for mitigation. When considering the responses of these species to natural lighting cues, a range of papers were identified which highlighted the use of the setting sun to calibrate internal compasses or to trigger feeding, and the response to lunar lighting cycles. As a practical response to these deficiencies in lamp data and applicable research, we developed three spatial indicators covering the national extent which reflected three mechanisms by which species might be exposed to lighting. The first identifies priority habitats immediately adjacent to bright emissions, the second uses visibility analysis to identify light polluted viewsheds and the third identifies habitats where natural lunar cycles in sky brightness are undermined.peerReviewe

Lead Ammunition and Illegal Poisoning: Further International Agreements Are Needed to Preserve Vultures and the Crucial Sanitary Service They Provide

Peer reviewe

Use of integrated modeling to enhance estimates of population dynamics obtained from limited data

Demographic data of rare and endangered species are often too sparse to estimate vital rates and population size with sufficient precision for understanding population growth and decline. Yet, the combination of different sources of demographic data into one statistical model holds promise. We applied Bayesian integrated population modeling to demographic data from a colony of the endangered greater horseshoe bats (Rhinolophus ferrumequinum). Available data were the number of subadults and adults emerging from the colony roost at dusk, the number of newborns from 1991 to 2005, and recapture data of subadults and adults from 2004 and 2005. Survival rates did not differ between sexes, and demographic rates remained constant across time. The greater horseshoe bat is a long-lived species with high survival rates (first year: 0.49 [SD 0.06]; adults: 0.91 [SD 0.02]) and low fecundity (0.74 [SD 0.12]). The yearly average population growth was 4.4% (SD 0.1%) and there were 92 (SD 10) adults in the colony in year 2005. Had we analyzed each data set separately, we would not have been able to estimate fecundity, the estimates of survival would have been less precise, and the estimate of population growth biased. Our results demonstrate that integrated models are suitable for obtaining crucial demographic information from limited data.</p

Age and season-related habitat selection patterns of the bearded vulture (Gypaetus barbatus) in the Swiss Alps: a basis for predicting conflict-zones with wind energy construction

The recent increase of wind energy use in Central Europe incurs potential impacts on wildlife. Large soaring raptors, like the bearded vulture, are particularly exposed to collision risk with wind turbines as they sometimes converge in selecting fairly similar combinations of landscape and wind conditions. Considerable efforts and resources have been invested to re-instate the species in the European Alps. There exists a risk, however, that this success will be jeopardized by the sprawl of the wind parks across the alpine massif. We used a maximum entropy modelling approach to predict the potential distribution of the bearded vulture across the Swiss Alpine range using presence-only data. We adopted a stepwise fashion to tune model complexity by varying feature combinations and regularization intensity, selecting the settings that provided the most parsimonious model. We identified and ranked the environmental variables most relevant for the species and tested for differences in ecological requirements between two different age classes (adults and juveniles) in both the cold and the warm season separately. The resulting models had a high accuracy in predicting habitat suitability (mean AUC across 5-folds cross validation ≥ 0.81) in each season for both age classes. Adults and juveniles showed different seasonal habitat selection patterns: whereas for juveniles the most important environmental variable was food availability, particularly ibex density (relative contribution: 40.9% in summer and 25.9% in winter), for adults climatic conditions were more important (altitude with 24.9% contribution in summer and average precipitation with 30.6% contribution in winter). When considering both age classes 67% of the Swiss Alpine range offered suitable habitat for the species, with range shifts between the cold and warm season. This analysis provides a first, broad-scale overview of the species distribution across the Swiss Alps and thus areas of potential conflict with wind energy construction. We will now further investigate flight altitudes and movement patterns at a fine spatial scale in order to identify the sites bearded vultures use most intensively at risky flight heights, i.e. within the rotor-swept area. The results will be integrated into a planning tool that will help avoiding conflicts between wind energy construction and vulture conservation.peerReviewe

Conservation science relevant to action: A research agenda identified and prioritized by practitioners

A wide gap between research and practice hinders the implementation of biodiversity conservation recommendations. As subjects studied by conservation scientists might bear little relevance for implementation, surveys have identified and framed research questions relevant to conservation in practice. No attempts to prioritize these questions have yet been published, although it would provide invaluable information for steering practice-oriented research. We surveyed Swiss conservation practitioners with the aim of identifying and prioritizing their needs in terms of useful scientific information. A first inductive survey of a selected subgroup generated a list of relevant research questions that were reformulated to be generalizable to all main Swiss ecosystems. The resulting compiled questionnaire was submitted through an online platform to all officially registered practitioners who were asked to rate the importance to their own field of expertise of each question, to nominate possibly omitted, subsidiary questions and to specify ‘‘hot topics’’ typically relevant to their field. Most respondents operated in several ecosystems, which facilitated the identification of general and ecosystem-related research priorities. Generally, questions related to economic, societal and stakeholder conflicts were found to be more important than conceptual questions. Questions concerning single-species were rated higher than ecosystem-related questions. Subsidiary questions and hot topics were subsumed and integrated into a final catalogue of research questions. By identifying and framing scientific questions of both general practical relevance and specific regional importance, this study provides a practice-oriented research agenda and a basis for developing conjoint activities with the intention to bridge the gap between conservation science and action