Facoltà di Scienze Matematiche, Fisiche e Naturali Dipartimento di Biologia e Biotecnologie “C. Darwin” Dottorato in Biologia Ambientale ed evoluzionistica Curriculum. Biologia Animale (XXIII Ciclo) Birds and climate change: possible scenarios for the European species Dottorando Tutors Alessandro Montemaggiori Prof. Luigi Boitani Matricola: 648658 Dott. Luigi Maiorano Anno Accademico 2017/2018 Cover photo: Corn buntings (Emberiza calandra) by loek van de Leur 2 INDEX 1. EXTENDED ABSTRACT ............................................................................................ 4 2. INTRODUCTION..................................................................................................... 11 2.1 Climate change: what are we speaking about?............................................................ 11 2.2 Consequences of climate change on natural communities and birds .......................... 14 2.3 Aim of the thesis and chapters’ summary .................................................................... 19 3. CLIMATE CHANGE AND MIGRATION #1: ............................................................ 30 The timing of spring migration in trans-Saharan migrants: a comparison between Ottenby, Sweden and Capri, Italy...................................................................................... 30 4. CLIMATE CHANGE AND MIGRATION #2: ............................................................ 38 Temperature and rainfall anomalies in Africa predict timing of spring migration in trans- Saharan migratory birds .................................................................................................... 38 5. CLIMATE CHANGE AND SPECIES DISTRIBUTION: ............................................... 51 Threats from Climate Change to Terrestrial Vertebrate Hotspots in Europe ...................... 51 6. CLIMATE CHANGE AND SPECIES CONSERVATION: ........................................... 66 On how much biodiversity is covered in Europe by national protected areas and by the Natura 2000 network: insights from terrestrial vertebrates ................................................ 66 7. CLIMATE CHANGE AND SPECIES VULNERABILTY: .............................................. 77 Assessing species vulnerability to climate change within European birds .......................... 77 8. COMBINING EXPERT-BASE AND STATISTICAL APPROACH: ............................... 87 Modelling the response of European breeding birds to climate change: combining expert-base and statistical approach ................................................................................. 87 9. CLIMATE CHANGE AND TROPHIC NETWORKS: .................................................. 89 Spatial analyses of multi-trophic terrestrial vertebrate assemblages in Europe.................. 89 10. CONCLUSIONS .................................................................................................... 115 11. REFERENCES ........................................................................................................ 120 12. ACKNOWLEDGMENTS ........................................................................................ 126 3 1. EXTENDED ABSTRACT Climate Change (CC) is emerging as the greatest threat to natural communities in many, if not most, of the world’s ecosystems in coming decades, with mid-range climate change scenarios expected to produce greater extinction rates than habitat loss, currently deemed the top threat to biodiversity. To foresee the biodiversity response to CC has therefore become a crucial field of research, especially in terms of management and conservation. The aim of my PhD was to explore the impact of the CC on 542 bird species regularly breeding in Europe and Turkey. Background Birds are the best known of the large and adaptively diversified classes of animals. According to the last Red List of Threatened Species (IUCN, 2017), 1,375 bird species of the global 10,965 are threatened with extinction (13%). In Europe 43% of 542 regular breeding species are listed as 'threatened' or 'near threatened' (BirdLife International, 2017). CC affects birds in different ways; it can alter distribution, abundance, behavior, even genetic composition. It can also affect the timing of events like migration or breeding. Extinction rates predicted for entire communities, populations or bird species because of CC are frightening. I had the chance to explore the impact of CC on the phenology of trans-Saharan migratory birds by analyzing the data collected for decades during spring migration across the Mediterranean and northern Europe (Jonzén et al., 2006b; Saino et al., 2007). The results of these analyses highlight how the constant advance of arrival dates at stop-over sites and reproductive territories is correlated with the weather conditions at wintering quarters and on the Mediterranean coasts of Africa, which influence the speed of migration. More recently, I used species distribution models (SDM) expert-based and validated with data of presence for each of the over 500 European breeding species, and correlative bioclimatic models that, through presence data and climatic variables sets, allowed me to obtain the current ecological niche of the species. By using the results of specific global circulation models (GCM) based on different climatic future scenarios it was possible to project forward the potential climatic distribution of each species. Comparing present and future I was able to obtain indicative results of the impact of CC on the European breeding bird species. 4 Chapters outline Where are the species and how much are exposed to climate change? In order to obtain specific SDMs, for each species I collected spatially explicit information on the extent of occurrence (EOO) over the entire study area (BirdLife’s EOOs digital database and national birds’ distribution atlases), as well as habitat requirements and all freely available presence data that I could readily access. Whenever possible, habitat requirements were used to refine the EOOs using an expert-based modeling approach, while points of presence were used to evaluate the reliability of the same models. Habitat requirements were defined by me and published literature, and I considered three environmental variables that I assumed to be informative to model species distribution: land cover, elevation and distance to water. For land cover I used GlobCover V2.2 (offering a complete coverage of our study area with a 300m pixel size and 46 land-use/land-cover classes). I obtained data on elevation from the Shuttle Radar Topography Mission database with a 250m pixel size, while data on running and standing water bodies were obtained from the CCM2 v2.1 river and catchments database compiled by the European Joint Research Center. I used the data collected to assign to each of the 46 GlobCover land- use/land-cover classes a suitability score. Whenever possible, I recorded the maximum and the minimum elevations at which a stable population of a given species can be found, and the maximum distance to water at which they have been recorded. So, I combined the elevation range with distance to water and habitat suitability scores to refine the available EOOs and obtained a model of the current species distribution with a cell size of 300m (resolution of the available environmental layers). Finally, I collected all the readily and freely available points of presence and used them to evaluate the reliability of the expert-based distribution models. I used the expert-based distribution models to calculate species richness maps for all breeding species together, species of conservation concern, endemic species. The top 10% richest cells in each map represented the hotspots of species richness. Average monthly precipitation and temperature were projected using climate model outputs made available through the Intergovernmental Panel on Climate Change (IPCC) Data Distribution Centre. Following, it was defined an ensemble of forecasts of climate change considering four different global circulation models and more than one emission scenarios. In this way it was possible to generate an index of risk of exposure to extreme climates that was used to identify the areas with a significant association between hotspots of diversity and high risk of exposure to extreme climates. 5 The results I obtained (Maiorano et al., 2013) outline that the richness hotspots for all European breeding birds are within northern central Europe and western Russia. An important hotspot for threatened species is in the eastern-central part of the study area while the species whose distribution is mainly European (‘endemic’ species) concentrate in northern central Europe, Greece, Alps and Iberian Peninsula. The analyses’ results suggest that the main hotspots of biodiversity for European breeding birds may be extensively influenced by the climate change projected to occur over the coming decades, especially in the Mediterranean bioregion, posing serious concerns for biodiversity conservation. How much protected are European birds? In order to understand the effectiveness of the current conservation tools existing for European birds, which, as already seen, are destined to undergo significant environmental changes, often in areas where high levels of biodiversity persist, a gap analysis of the entire system of European protected areas (PAs) and the Natura2000 network (N2K: the most important European biodiversity conservation effort carried out on a regional scale) was performed by using validated species