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The group!
Researchers working together in this project:
Sara Castro
Has been working with us:
Carles Molina
Technicians:
Ana Carvajal
Oscar González
The project
Invasive species represent a driver of global change and biodiversity loss, causing extinctions of native species, changes in ecosystem structure and function, and loss of ecosystem services worldwide. Their ability to successfully invade areas in which they have not evolved represents an intriguing ecological and evolutionary paradox. Understanding the reasons behind such paradox will improve our capacity for preventing, controlling and mitigating the impacts of invasions.
Most previous work on invasions has focused on identifying traits that characterise invader species. Improving our understanding of biological invasions requires complementary work on the characteristics that make native communities more or less prone and vulnerable to such invasions. Three mechanisms, not necessarily exclusive, have been proposed as determinants of the invasibility and vulnerability of native communities: (1) Biotic resistance, mediated by the effect of the diversity of competitors and natural enemies (predators, parasites and/or pathogens) from native communities. (2) Enemy release, i.e. the escape from specialized natural enemies present in the original range of invasive species but absent at the invaded communities, where generalist enemies are not successful in controlling the invader. (3) Biotic facilitation, i.e. the cooption of mutualistic and comensalistic networks at the invaded range.
In this project, we evaluate the effects of recipient communities on the success and impact of invasive species, and the relative importance of the three mechanisms proposed as determinants of such effects: biotic resistance, enemy release, and biotic facilitation. We will use two model species with contrasting characteristics: a global invader of continental origin, the Argentine Ant Linepithema humile, and an insular endemic that invaded insular and continental localities, the Ibiza Wall Lizard Podarcis pityusensis. We expect differences between both alien species in their sensitivity to biotic resistance (low in ants, high in lizards), level of escape from natural enemies (high for ants, low for lizards) and capacity to coopt mutualistic and comensalistic networks (high for ants, high for lizards) at the invaded range. We make use of an additional
contrast between continental and insular localities, differing in the biological diversity of their recipient communities – and, therefore, in expected levels of biotic resistance, abundance and richness of natural enemies, and complexity of mutualistic/commensalistic networks.
Using these focal species and spatial setting, the project will assess biotic resistance effects through a combination of surveys of the diversity and abundance of native species in pairs of invaded and uninvaded sites, combined with field experiment aimed at disentangling invasiveness and vulnerability effects. Enemy release effects will be assessed using surveys and field experiments to quantify predation rates and parasite/pathogen loads for native and invasive species and (for IWL) at native and invaded ranges. We will also assess potential changes in morphological, functional behavioural traits related to antipredator responses. Biotic facilitation effects will be assessed by quantifying rates and patterns of carcase removal, seed removal (ants) and fruit consumption (lizards) in invasive and native species. All these results will be compared by means of comparative analysis, used to evaluate the main hypotheses outlined above.
Sampling sites
Lovely places such as
San Juan de Gaztelugatxe, Basque Country
Doñana Biological Reserve, Huelva
Balearic Islands