Roles of survival and dispersal in reintroduction success of Griffon vulture (Gyps fulvus).
The success of reintroduction programs greatly depends on the amount of mortality and dispersal of the released individuals. Although local environmental pressures are likely to play an important role in these processes, they have rarely been investigated because of the lack of spatial replicates of reintroduction. In the present study, we analyzed a 25-year data set encompassing 272 individuals released in five reintroduction programs of Griffon Vultures (Gyps fulvus) in France to examine the respective roles of survival and dispersal in program successes and failures. We use recent developments in multi-strata capture-recapture models to take into account tag loss in survival estimates and to consider and estimate dispersal among release areas. We also examined the effects of sex, age, time, area, and release status on survival, and we tested whether dispersal patterns among release areas were consistent with habitat selection theories. Results indicated that the survival of released adults was reduced during the first year after release, with no difference between sexes. Taking into account local observations only, we found that early survival rates varied across sites. However when we distinguished dispersal from mortality, early survival rates became equal across release sites. It thus appears that among reintroduction programs difference in failure and success was due to differential dispersal among release sites. We revealed asymmetrical patterns of dispersal due to conspecific attraction: dispersers selected the closest and the largest population. We showed that mortality can be homogeneous from one program to another while, on the contrary, dispersal is highly dependent on the matrix of established populations. Dispersal behavior is thus of major interest for metapopulation restoration and should be taken into account in planning reintroduction designs.
UMR 5173 MNHN-CNRS-UPMC (Conservation des Espèces, Restauration et Suivi des Populations), Museum National d'Histoire Naturelle, 61 Rue Buffon, ler Etage, 75005 Paris, France. legouar@mnhn.fr
Pascaline
P
Le Gouar
Alexandre
A
Robert
Jean-Pierre
JP
Choisy
Sylvain
S
Henriquet
Philippe
P
Lecuyer
Christian
C
Tessier
François
F
Sarrazin
D000367:Age Factors; D000818:Animals; D017753:Ecosystem; D046093:Falconiformes; D005260:Female; D005602:France; D008297:Male; D008954:Models, Biological; D011157:Population Dynamics; D012737:Sex Factors; D013997:Time Factors