CONSERVATION OF ENDANGERED ENDEMIC SEABIRDS WITHIN A MULTI-PREDATOR CONTEXT: THE BARAU'S PETREL IN RÉUNION ISLAND
Article first published online: 20 JUL 2010
©2010 Wiley Periodicals, Inc.
Natural Resource Modeling
Volume 23, Issue 3, pages 381–436, August 2010
How to Cite
DUMONT, Y., RUSSELL, J. C., LECOMTE, V. and LE CORRE, M. (2010), CONSERVATION OF ENDANGERED ENDEMIC SEABIRDS WITHIN A MULTI-PREDATOR CONTEXT: THE BARAU'S PETREL IN RÉUNION ISLAND. Natural Resource Modeling, 23: 381–436. doi: 10.1111/j.1939-7445.2010.00068.x
- Issue published online: 20 JUL 2010
- Article first published online: 20 JUL 2010
- Received by the editors on 31st October 2009. Accepted 13th May 2010.
- Population dynamics;
- intraguild predation;
- nonstandard finite difference method;
- dynamic consistency;
- numerical simulation
Abstract Seabirds breeding on islands are vulnerable to introduced predators, such as rats and cats, and the removal of such predators is generally viewed as a priority for seabird conservation and restoration. However, multiple invasive mammal species interacting may generate unexpected outcomes following the removal (eradication) of one species. Generally these indirect interactions are not well understood or demonstrated. We propose and study a prey (seabird)-mesopredator (rat)-superpredator (cat) model, taking into account the juvenile stages in the prey population, in order to direct conservation management for seabird conservation. We give a more biologically realistic differential system than those studied before (Courchamp et al. ; Fan et al. ), in particular for long-lived seabird species. We present a theoretical study and show existence and uniqueness of a positive solution as well as a qualitative study of the equilibria that may appear. Because standard numerical methods, usually implemented in scientific softwares, can fail to give the right biological approximations (Anguelov et al. ), we propose a reliable algorithm that preserves most of the qualitative properties of the continuous system, using the theory of nonstandard finite difference methods. Finally, we use biologically realistic parameters available for the representative Barau's petrel (Pinet et al. ), an endemic species from Réunion island, to present numerical simulations that support the theoretical study. Cats play the major role in seabird prey population dynamics. Seasonality in seabird breeding delays but does not prevent extinction. In all scenarios, cat control (or preferably eradication) is imperative to prevent extinction of vulnerable long-lived seabirds, like the Barau's petrel.