Patterns of distribution and landscape connectivity of the stag beetle in a human-dominated landscape

Urbanisation and the spread of agriculture have resulted in high levels of forest loss, habitat fragmentation and degradation in many regions of the world. In Italy, the Po Plain is the most human-dominated landscape of the country and, after decades of exploitation, old-growth forests have been reduced to small and isolated patches, often threatened by invasive tree species such as the black locust (Robinia pseudoacacia). In these habitats, the occurrence of many forest-dependent species is related to the quality and availability of suitable areas, as well as the connectivity between the remaining forested patches. Thus, recently developed species distribution models have been applied, namely the Ensemble of Small Models (ESMs), to identify areas of occurrence for a rare and protected saproxylic beetle species, the stag beetle Lucanus cervus and the inverse of the resulting distribution maps as resistance maps have been used to estimate landscape connectivity for this species. Response curves suggested that the probability of the stag beetle occurrence increased with habitat diversity, grassland coverage and native forests, especially oak and mixed forests. The other forest coverage, such as those with black locust, beech, chestnut and black cherry, showed a unimodal relationship peaking approximately at 70%, 8%, 55% and 13% respectively. The stag beetle occurrence was unimodal related to distance to watercourses and distance to human settlements and negatively related to shrub-lands, croplands, sparse and dense human settlements. Landscape connectivity showed similar patterns, except for oak forest coverage, which showed a negative relationship to landscape connectivity. In conclusion, stag beetles can persist in a human dominated landscape only in the presence of forest patches, including those with black locust trees. It is also inferred that ESMs may be suitable for modelling rare species distributions and estimating landscape connectivity to promote species conservation

Ecological factors affecting foraging behaviour during nestling rearing in a high-elevation species, the White-winged Snowfinch (Montifringilla nivalis)

During breeding, parents of avian species must increase their foraging efforts to collect food for their offspring, besides themselves. Foraging trips are thus a key aspect of the foraging ecology of central-place foragers when rearing their offspring. However, studies of the foraging ecology of high-elevation specialists inhabiting harsh environments are scarce. Here we report for the first time quantitative information on ecological determinants of foraging trips in the White-winged Snowfinch (Montifringilla nivalis), a high-elevation specialist threatened by climate warming. We focused on seasonal, meteorological, habitat and social factors affecting distance and duration of foraging trips performed during nestling rearing, recorded by visual observations in the Italian Alps. Based on 309 foraging trips from 35 pairs, we found that trips lasted 6.12 min and foraging areas were located at 175 m from the nest site on average. Trip duration was affected by snow cover (longer at intermediate cover), distance travelled and wind, while distance travelled was affected by snow cover (being higher at intermediate cover) and trip duration. Foraging individuals thus travelled farther and spent more time at areas characterized by intermediate snow cover, implying the presence of snow margins. It is likely that at such snow patches/margins snowfinches collected food for self-maintenance, besides that for their offspring, or collected more food items. Any reduction of snow cover during the breeding season, as expected under current climate warming, will severely alter foraging habitat suitability. Conserving suitable foraging habitats in the nest surroundings will be crucial to buffer such negative impacts

Thermal niche predicts recent changes in range size for bird species

Species’ distributions are strongly affected by climate, and climate change is affecting species and populations. Thermal niches are widely used as proxies for estimating thermal sensitivity of species, and have been frequently related to community composition, population trends and latitudinal/elevational shifts in distribution. To our knowledge, no work has yet explored the relationship between thermal niche and change in range size (changes in the number of occupied spatial units over time) in birds. In this study, we related a 30 yr change in range size to species thermal index (STI: average temperature at occurrence sites) and to other factors (i.e. birds’ associated habitats, body mass, hunting status) potentially affecting bird populations/range size. We analysed trends of breeding bird range in Italy for a suite of poorly studied cold-adapted animals potentially sensitive to global warming, and for a related group of control species taxonomically similar and with comparable mass but mainly occurring at lower/warmer sites. We found a strong positive correlation between change in range size and STI, confirming that recent climatic warming has favoured species of warmer climates and adversely affected species occupying colder areas. A model including STI and birds’ associated habitats was not so strongly supported, with forest species performing better than alpine open habitat and agricultural ones. In line with previous works highlighting effects of recent climate change on community composition, species’ population trends and poleward/upward distributional shifts, we found STI to be the most important predictor of change in range size variation in breeding birds

Coping with unpredictable environments: fine-tune foraging microhabitat use in relation to prey availability in an alpine species

Microhabitat utilisation holds a pivotal role in shaping a species’ ecological dynamics and stands as a crucial concern for effective conservation strategies. Despite its critical importance, microhabitat use has frequently been addressed as static, centering on microhabitat preference. Yet, a dynamic microhabitat use that allows individuals to adjust to fine-scale spatio-temporal prey fluctuations, becomes imperative for species thriving in challenging environments. High-elevation ecosystems, marked by brief growing seasons and distinct abiotic processes like snowmelt, winds, and solar radiation, feature an ephemeral distribution of key resources. To better understand species’ strategies in coping with these rapidly changing environments, we delved into the foraging behaviour of the white-winged snowfinch Montifringilla nivalis, an emblematic high-elevation passerine. Through studying microhabitat preferences during breeding while assessing invertebrate prey availability, we unveiled a highly flexible microhabitat use process. Notably, snowfinches exhibited specific microhabitat preferences, favoring grass and melting snow margins, while also responding to local invertebrate availability. This behaviour was particularly evident in snow-associated microhabitats and less pronounced amid tall grass. Moreover, our investigation underscored snowfinches’ fidelity to foraging sites, with over half located within 10 m of previous spots. This consistent use prevailed in snow-associated microhabitats and high-prey-density zones. These findings provide the first evidence of dynamic microhabitat use in high-elevation ecosystems and offer further insights into the crucial role of microhabitats for climate-sensitive species. They call for multi-faceted conservation strategies that go beyond identifying and protecting optimal thermal buffering areas in the face of global warming to also encompass locations hosting high invertebrate densities

Glorious past, uncertain present, bad future? : assessing effects of land-use changes on habitat suitability for a threatened farmland bird species

Land-use changes have strong impacts on biological communities. Among them, land abandonment is threatening a large number of conservation-concern species associated with semi-natural habitats shaped by \u2018traditional\u2019 farming. We focused on the red-backed shrike as a model for investigating the effect of land abandonment on a threatened bird species, and used historical data to model dynamic scenarios. We explored variations in habitat suitability from the 1950s to the present and predicted possible future variations. After investigating local habitat preferences of the species, we formulated a spatially explicit model of habitat suitability for shrikes according to current land-use types; then, we evaluated past habitat suitability, by applying the model to three known past scenarios, and simulated the habitat changes after land abandonment. By combining a habitat-association approach with past and future land use scenarios, we assessed and predicted the effects of habitat changes caused by abandonment. Shrike occurrence was favoured by the cover of four types of grassland and of shrubland with trees, and negatively affected by broadleaved woodlands. The current average habitat suitability is less than half of what it was in the 1950s. Future predictions in a complete abandonment scenario suggest that important decrease could be expected 10 or 20 years after abandonment, and that after 30 years the red-backed shrike would be completely extinct. Alternative scenarios involving partial abandonment suggested that subsidy policies may mitigate the effects of abandonment. Knowing land-use dynamics allowed the exploration of effects of land-use changes and corroborated the importance of low-intensity farming for conservation

Potential distribution of a climate sensitive species, the White-winged Snowfinch Montifringilla nivalis in Europe

The White-winged Snowfinch Montifringilla nivalis nivalis is assumed to be highly threatened by climate change, but this high elevation species has been little studied and the current breeding distribution is accurately known only for a minor portion of its range. Here, we provide a detailed and spatially explicit identification of the potentially suitable breeding areas for the Snowfinch. We modelled suitable areas in Europe and compared them with the currently known distribution. We built a distribution model using 14,574 records obtained during the breeding period that integrated climatic, topographic and land-cover variables, working at a 2-km spatial resolution with MaxEnt. The model performed well and was very robust; average annual temperature was the most important occurrence predictor (optimum between c.-3°C and 0°; unsuitable conditions below -10° and above 5°). The current European breeding range estimated by BirdLife International was almost three times greater than that classified as potentially suitable by our model. Discrepancies between our model and the distribution estimated by BirdLife International were particularly evident in eastern Europe, where the species is poorly monitored. Southern populations are likely more isolated and at major risk because of global warming. These differences have important implications for the supposed national responsibility for conservation of the species and highlight the need for new investigations on the species in the eastern part of its European range

Recovery of high mountain Alpine lakes after the eradication of introduced brook trout Salvelinus fontinalis using non-chemical methods

The final publication is available at Springer via http://dx.doi.org/10.1007/s10530-018-1867-0Fish stocking is a serious threat to originally fishless mountain lakes. We used non-chemical eradication methods (i.e. gillnetting and electrofishing) in four high mountain lakes in the Gran Paradiso National Park (Western Italian Alps) to eradicate alien brook trout Salvelinus fontinalis. Data of amphibians, macroinvertebrates, zooplankton, chlorophyll-a, nutrient concentrations, and water transparency were used as indicators of the recovery process. All treated lakes were returned to their original fishless condition in spite of their different sizes and habitat complexity, without permanent negative side-effects for native species. Several ecological indicators showed that many impacts of introduced fish can be reversed over a short time period following eradication. The present study adds to a still growing body of specialized literature on the recovery of habitats after the eradication of alien species and provides further evidence that physical eradication methods are effective and can be part of a more general strategy for the conservation of high mountain lake biota