Cooperative breeders and Allee effect

    This aspect of our research is headed by Franck Courchamp. It deals with the dynamics of obligately cooperative breeding species, and a dynamical process generated by their specific social system, the Allee effect.

We approach this subject by a combination of mathematical modelling and of analyses of field data, in general collected by collaborators. The questions we address in this context concern two main model species: African Wild Dogs, or Painted hunting dogs Lycaon pictus (photo above) and suricates or meerkats, Suricata suricatta (photo below).

When their population size decreases, most species benefit from an associated decrease in intraspecific competition, leading to increased reproduction and/or survival of survivors, which helps the population reach rapidly its optimal size. The Allee effect describes a scenario in which populations at low numbers are affected by a positive relationship between population growth rate and density, which increases their likelihood of extinction. Thus, some population at low density can suffer from a lower recruitement or a higher mortality, leading to a further population decrease. The endpoint of this loop process is often the extinction of the population. The importance of this dynamic process in ecology has been under-appreciated and recent evidence now suggests that it might have an impact on the population dynamics of many plant and animal species. For a more precise definition and detailed examples, please refer to this review.

Another aspect of this research is linked to our theme of biological invasions. We aim to study the importance of accounting for the Allee effect in interspecific relationships of the host-parasite type. In particular, we wish to determine the effects of taking this process into account in classical host-parasite mathematical models. This approach has implications both for the conservation of threatened species with Allee effects (such as painted hunting dogs), and for the management of populations that are to be protected from introduced species, notably through biological control (pathogens). This work is carried out by Anne Deredec, doing her Ph. D. under the supervision of Franck Courchamp.

If you are interested by this theme, you can download a few articles on this subject, by following this link.
    For further information on applications to work with us, please follow this link.