Biological invasions and conservation

    Our group is interested in the problems of biodiversity conservation in the context of biological invasions. The main biological system we use is the oceanic island, which regroups many advantages for scientific studies (finite and often small area, non-redundant and relatively simple trophic webs, wide array of different conditions, ubiquity of invasive phenomenons). Moreover, oceanic island ecosystems are characterised bcterised by both a high biodiversity and a large proportion of threatened species.

    Biologic invasions are considered to be the second largest threat to biodiversity, after habitat destruction. The introduction of non-native plant and animal species causes important modifications in native communities that have evolved in their absence. This is especially the case for oceanic islands, which communities present relatively little diversification, simplified trophic webs and high rates of endemism. Because of the considerable ecological fragility of islands, the introduction of alien species currently constitutes a major threat to most of the endemic species on numerous islands throughout the world. Around 90% of vertebrate extinctions since 1600 were of island form. Nearly half them were primarily caused by the invasion of exogenous species

    The research program on biological invasions is headed by Franck Courchamp and is based on several main points :

1/ better understanding of the impact of invasive species from the study of a few flag species, such as sea turtles or sea birds.

2/ characterisation of the optimal control methods of invasive species with regards to ecological and physical conditions, and to secondary effects that can be triggered by restoration programs.

3/ study of concrete cases of invaded island conservation programs, including habitat and trophic web characterisation, invasive species control program, and ecosystem restoration.

    These questions will be tackled by a combinatiombination of mathematical modelling and field work. But what is the point of modelling in the context of invasive species control?

    Cats introduced into Australia kill more than 100 native species of birds, 50 mammals, 50 reptiles, and numerous amphibiens et invertebrates.
    In Western Autralia only, tens of millions of vertebrates are killed each year by these predators.
    Cats have been introduced on at least 123 of the 131 major oceanic island groups and are believed responsible for more than a quarter of island species extinctions due to introduced predators.
    Cats are however but one of the many introduced species.

     Photo Kathie Atkinson, Australistralian Natural History (1993), 24: 44-52

    If you are interested by this theme, you can download a few articles on this subject, by following this link. And if you are even more interested, maybe we can produce some more together!