Waterbird Species Are Highly Sensitive to Wetland Traits: Simulation-Based Conservation Strategies for the Birds of the Sicilian Wetlands (Italy).

In this study, we (a) formulated a general hypothesis about how wetland (functional and structural) traits influence avian diversity, (b) turned this hypothesis into a non-parametric Bayesian network, (c) disentangled the direct and indirect effects of the variables influencing waterbird species, and (d) simulated the changes expected to the levels of avian diversity as a result of numerous counterfactual and management scenarios. We applied our framework to the Sicilian wetlands as a whole; then, we downscaled simulations locally to a wetland of particular interest (Pantano Bruno). We found that (1) waterbird species are highly sensitive to wetland traits; (2) wetland traits have both direct and indirect effects upon alpha avian diversity; (3) the direct and indirect effects of wetland traits can be contrasting; (4) water level fluctuations (benefit), diversions (cost), and salinity (cost) are key factors for waterbird conservation; (5) these wetlands have the potential for hosting a level of alpha avian diversity that is double the baseline (from 19 to 38 species); (6) these wetlands are prone to ecological collapse if all traits deteriorate (from 19 to 6 species per wetland); and (7) the ecological information gained at the regional scale can be properly downscaled to the local scale to make inferences on single wetlands.

Simulation Modeling Unveils the Unalike Effects of Alternative Strategies for Waterbird Conservation in the Coastal Wetlands of Sardinia (Italy).

The Sardinian wetlands (Italy) act as stopover sites for many migratory birds along the central eastern Mediterranean bird flyway. These wetlands are now severely threatened by human activities and climate change. Accordingly, we built a simulation framework to predict the effects of several counterfactual and management scenarios on the level of avian diversity in the coastal wetlands of Sardinia. We found that the alpha avian diversity (i.e., the mean number of avian species per wetland) is destined to (a) decrease due to the most likely increase in water salinity, water discharges, and tourism pressure; and (b) halve (from 14.9 to 7.4, with 9 wetlands out of 22 predicted to host only between two and five waterbird species) in the worst possible scenario. However, the results also showed that proper management strategies could prevent and reverse such outcomes. Restrictions on tourism activities, water desalination, prevention of future saltwater intrusions, and the prohibition of water discharges could markedly favor the avian diversity in these wetlands, with an expected increase in the alpha avian diversity from 14.9 to 24.8 (and 10 wetlands out of 22 predicted to host from 29 to 32 waterbird species) in the best possible scenario. The importance of our results could be emphasized in the management plans of these important wetlands, most of which belong to the Natura 2000 network.

Identifying climate refugia for high-elevation Alpine birds under current climate warming predictions.

Identifying climate refugia is key to effective biodiversity conservation under a changing climate, especially for mountain-specialist species adapted to cold conditions and highly threatened by climate warming. We combined species distribution models (SDMs) with climate forecasts to identify climate refugia for high-elevation bird species (Lagopus muta, Anthus spinoletta, Prunella collaris, Montifringilla nivalis) in the European Alps, where the ecological effects of climate changes are particularly evident and predicted to intensify. We considered future (2041-2070) conditions (SSP585 scenario, four climate models) and identified three types of refugia: (1) in-situ refugia potentially suitable under both current and future climate conditions, ex-situ refugia suitable (2) only in the future according to all future conditions, or (3) under at least three out of four future conditions. SDMs were based on a very large, high-resolution occurrence dataset (2901-12,601 independent records for each species) collected by citizen scientists. SDMs were fitted using different algorithms, balancing statistical accuracy, ecological realism and predictive/extrapolation ability. We selected the most reliable ones based on consistency between training and testing data and extrapolation over distant areas. Future predictions revealed that all species (with the partial exception of A. spinoletta) will undergo a range contraction towards higher elevations, losing 17%-59% of their current range (larger losses in L. muta). We identified ~15,000 km2 of the Alpine region as in-situ refugia for at least three species, of which 44% are currently designated as protected areas (PAs; 18%-66% among countries). Our findings highlight the usefulness of spatially accurate data collected by citizen scientists, and the importance of model testing by extrapolating over independent areas. Climate refugia, which are only partly included within the current PAs system, should be priority sites for the conservation of Alpine high-elevation species and habitats, where habitat degradation/alteration by human activities should be prevented to ensure future suitability for alpine species.

Preserving the Mediterranean bird flyways: Assessment and prioritization of 38 main wetlands under human and climate threats in Sardinia and Sicily (Italy).

Wetlands provide a wide range of ecosystem services, including supplying the food and shelter for a rich assemblage of waterbirds and providing the stopover sites that allow birds to make migratory journeys. Human impact and the ongoing climate change are however reducing the ability of wetlands to provide such important services. Through field surveys, GIS analyses and climate projections, we assessed the status of, and threats to, 38 largest wetlands belonging to the Mediterranean bird flyways in Sardinia and Sicily (Italy). We then combined ten decision criteria about avifaunal diversity and human/climate threats in order to prioritize the studied wetlands from most to least worthy of urgent interventions. Results showed that the main wetlands of these two regions have distinct demands with regard to the kind of actions required, going from the mitigation of tourism pressure to the prevention of climate-induced water shortage in summer. Furthermore, clear priorities for interventions emerged in both regions. Our study has direct implications for managers and researchers attempting to assess wetland conditions and set conservation priorities, thus offering a tool for deciding urgent interventions on the main stopover sites along the Mediterranean bird flyways.

Habitat, climate, topography and management differently affect occurrence in declining avian species: Implications for conservation in changing environments.

Climate and land-use change are the most severe threats to biodiversity; their effects are often intermingled, also with those of landscape/habitat management. Birds of mountain grassland are declining throughout Europe. Disentangling climate effects from those of land-cover and management on their occurrence is essential to identify distribution drivers, potential impacts of climate/land-use changes, and effective conservation strategies. We investigated the occurrence of water pipit (elevation specialist), skylark and red-backed shrike (elevation generalists) in Central Apennines, Italy (750-2130 m asl), using point counts. Topographic/climatic, land-cover and management fine-scale variables were considered as potential occurrence predictors in Generalized Linear Models. For all species, combining different types of predictors led to the most accurate models, but the relative importance of single-groups varied: land cover was the most important for skylark, climate/topography for water pipit, all three groups had similar support for red-backed shrike. Skylark was positively affected by solar radiation and grassland cover, and negatively by bare ground, hedgerows, rocks, shrubland, ski-pistes and buildings, confirming sensitivity to anthropic alteration of semi-natural grassland. Water pipit was favoured by grazing and negatively impacted by shrubland and average temperature (most important predictor). Red-backed shrike was affected negatively by broadleaved forest and grazing occurrence, quadratically by isolated shrubs and positively by grassland cover. Climate was a fundamental determinant of water pipit occurrence, but not for the other species. Land-cover was important for all species and also management factors were invariably included in models. Climate, habitat and management factors differently contributed to occurrence patterns in these declining species. Conservation strategies need to embrace landscape planning to preserve grassland extents/mosaics, identify climate refugia for water pipit and implement dedicated management (preventing new ski-pistes over areas suitable for birds and carefully planning grazing). It should be feasible to combine local, sustainable economies with biodiversity conservation into landscape planning for Central Apennines.