UNIVERSITÀ DEGLI STUDI DI TRIESTE XXIX CICLO DEL DOTTORATO DI RICERCA IN AMBIENTE E VITA REGIONE FVG – FONDO SOCIALE EUROPEO LA NEOFITIZZAZIONE DEGLI HABITAT E LA SUA RIPERCUSSIONE SULLE COMPONENTI VEGETALI E SULL’ENTOMOF$UNA DEL CARSO DINARICO ITALIANO Settore scientifico-disciplinare: BIO/03 Botanica ambientale e applicata DOTTORANDA COSTANZA UBONI COORDINATORE PROF. GIORGIO ALBERTI SUPERVISORE DI TESI DOTT.SSA MIRIS CASTELLO ANNO ACCADEMICO 2016/2017 Index General Introduction 2 Study area 15 Checklist of the species 16 Chapter 1 20 Chapter 2 37 Chapter 3 58 Chapter 4 97 General Conclusion 117 Appendix 1 – Ongoing projects 119 Appendix 2 – Collaboration with the University of Florence 141 Appendix 3 – Manuscript in preparation 145 Appendix 4 – Accepted Manuscript 152 Appendix 5 – Submitted, in review and published Manuscripts 162 1 General Introduction Colonization is a worldwide phenomenon considering the occupation of an habitat or a territory by a biological community, or the occupation of an ecological niche by a single population of a species (Onofri, 2011). Species can naturally colonize novel environments or they can expand their range, due to anthropogenic disturbances, into regions where they were not historically present. Moreover, human-mediated transport and human-activity allow more individuals and more species to reach new locations, more often and more quickly, ultimately resulting in colonization rates being greater than natural colonization (Blackburn et al., 2014; Hoffmann & Courchamp, 2016). These species, the so called exotic species (Sax, 2002a,b) or non-native species (Hejda et al., 2009), necessarily go through the same stages of introduction, establishment and spread of native species (Hoffmann & Courchamp, 2016). This happens because they experience the same barriers of survival, reproduction, dispersal and further range expansion (Hoffmann & Courchamp, 2016). Is noteworthy that biological invasions and natural colonization differ in processes and mechanisms in ways that are crucial for science, management, and policy (Wilson et al., 2016). Among introduced species, only a subset of them forms self-sustaining populations, becoming naturalized (Sax, 2002a, b). The introduction of species beyond their native range, as a direct or indirect effect of human action, does not always causes changes in the ecosystems they are introduced to. Sometimes, these species are considered terrestrial habitats modifier (Schirmel & Buchholz, 2013), and their changes in ecosystems are dramatic and may negatively affect resident species (Hejda et al., 2009), with changes in natural faunal composition and food-webs. Moreover, they can cause extinction of native species, loss of biological diversity (i.e., genetic, species, and ecosystem diversity), radical changes in ecosystem functioning (Hejda et al., 2009), changes in natural habitats (Blackburn et al., 2014), in genetic composition of native populations, behavior patterns, species richness and abundances, phylogenetic and taxonomic diversity (Blackburn et al., 2014), and threat the well- being of humans (Schlaepfer et al., 2010). But for the vast majority of non-native species no quantitative information is available on the consequences of such introductions (Jeschke et al., 2014). In many cases, however, they can also provide conservation benefits. Schlaepfer (2010) examined the ways in which non-native species currently contribute to conservation objectives. These include, for example, providing habitat or food resources to rare species, serving as functional substitutes for extinct taxa, and providing desirable ecosystem functions. The greatest part of non-native species will continue to cause biological and economic damage, and substantial uncertainty surrounds the potential future effects of all non-native species (Schlaepfer et al., 2010). Nevertheless, the proportion of non-native species that are viewed as benign or even desirable, will 2 slowly increase over time as their potential contributions to society and to achieving conservation objectives become well recognized and realized (Schlaepfer et al, 2010). For this reason, ecological impacts of invasive species should be carefully evaluated before any definitive assertion of harmfulness (Motard et al., 2015). Biological invasions and ecology of invasion are hot research topics, and the impact of species introduced outside their native range by humans is increasing in an era of globalization, also due to the global change that increases their tendency to spread over larger areas in close relationship with their triggering environmental driving force (Grigorescu, 2016). The study of non-native species became very popular in the last twenty years (Briggs, 2013; Díez et al., 2014), and recently this field has been undergoing an important shift in research priorities (Pyšek, 2008). Invasion biology has, over time, developed into the broader transdisciplinary field of invasion science. The heart of invasion science is the realization that biological invasions are not only a biological phenomenon: the human dimension of invasions is a fundamental component in the social-ecological systems, in which invasions need to be understood and managed (Wilson et al., 2016). Invasive tree species often form mono-specific stands and they are major drivers of environmental change (Richardson, 2011). One of the most important colonizer tree is Ailanthus altissima (Mill.) Swingle (Motard et al., 2011). A. altissima is a deciduous tree native to China, belonging to the Simaroubaceae family, which was first introduced in Europe by the French missionary Pierre d’Incaville, who sent seeds from Nanking to Paris in the of mid-XVIII° century (Enescu et al., 2016). After this first episode, this tree was planted mainly as ornamental plant in all continents (except Antarctica). Thanks to its fast expansion, it is nowadays considered as invasive in the most part of Europe (Motard et al., 2011), and actually it is cited as a concern for biodiversity according to the Global Invasive Species Database (GISD, 2017). A. altissima arrived in Italy in 1760 at the Botanic Garden of Padova. The first reason of this tree success is the vegetative reproduction ability to resprout and develop root networks forming dense clonal stands; the seconds reason is the sexual reproduction with a high production of samaras, that can persist on the plant during winter and disperse over long distances. The species is common in disturbed urban and anthropic areas, for example along roadsides and railroads, in park areas and in old fields (Vila et al., 2006; McAvoy et al. 2012; Motard et al., 2011; Motard et al., 2015; Enescu et al., 2016). A. altissima produces allopathic compounds that can reduce seedling in artificial conditions; it also has an insecticidal activity (Tsao et al., 2002; Motard et al., 2011 and 2015; Enescu et al., 2016) and its pollen is allergenic (Ballero et al., 2003) . It has been shown that this species can transform open ecosystems such as meadows or old fields 3 into closed forests (Kowarik & Böcker, 1984; Kowarik and Saümel, 2007). Moreover, it spreads and displaces native vegetation with a huge canopy cover, with a large amount of root suckers and thanks to allelopathy. The result is the impoverishment of biological diversity through competition (Motard et al., 2011). Invaded forest communities exhibit significantly lower floristic diversity, as evaluated by plant species richness, abundance and rarity indices, when compared to non-invaded adjacent zones (Motard et al., 2011). The species spontaneously invades not only disturbed microsites hardly colonized by other species, but also can penetrate forests through natural or artificial free space (Motard et al., 2011). An earlier study in forests colonized by A. altissima suggests that an increasing density of this plant is associated with a significantly lower floristic diversity (plant species richness, abundance and rarity indices), a lower soil microbial activity, with decreasing in abundance of Acari, Collembola, Coleoptera, and terrestrial Gastropoda. Contrary, increasing A. altissima density is linked to greater abundances of Lumbricidae and coprophagous Coleoptera (Motard et al., 2015). However, it is still unclear whether this impact is due to the direct action of A. altissima by phytotoxicity of the root system, or to the transformation of soil and litter fauna (Motard et al., 2011). Nevertheless, a detailed knowledge of the biology and ecology of individual invasive species remains at the core of invasion ecology, and of its practical applications. Specific case studies are thus an important tool in the quest for a better understanding of invasion phenomena (Pyšek, 2008). Due to the lack in information concerning the impact of A.altissima on terrestrial arthropods, we decided to study the impact of this tree on carabid beetles (Coleoptera, Carabidae) assemblages. Invertebrates are ubiquitous, taxon-rich and dominant organisms throughout the world (Wilson, 1987), and recently there has been an increase in awareness of their importance as indicators in conservation planning (Kremen et al., 1993; McGeoch, 1998; Paoletti, 1999; Angelini et al., 2002; Andersen et al., 2002; Hodkinson, & Jackson, 2005; Gavinelli et al., 2017). Arthropods form the greatest part of biodiversity in each ecosystem (Duelli et al., 1999; Niemelä, 2000; Buchholz et al., 2012; Twardowski, 2017) and if we consider Insects, they are really useful bio-indicators due to their rapid response to environment