Vol. 32 – 2006 - Ecologia Mediterranea
Vol. 32 – 2006 - Ecologia Mediterranea
Vol. 32 – 2006 - Ecologia Mediterranea
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ence of historical biogeographic patterns associated with<br />
Quaternary climatic changes, and the current ecological<br />
patterns associated with diverse disturbances (fragmentation,<br />
fire, grazing) or environmental changes, is examined.<br />
Three species with a distribution more or less narrow are<br />
studied: two snowflakes, Acis nicaeensis (Alliaceae)<br />
endemic from the Southern Maritime Alps and Acis fabrei,<br />
endemic from the Mont Ventoux, and Gentiana ligustica<br />
(Gentianaceae) endemic from the South-Western Alps in<br />
France and Italy.<br />
Phylogeographic data of G. ligustica combined with glacial<br />
history suggest the presence of several peripheral<br />
microrefugia in the south and in valley lowlands of the<br />
Maritime and Ligurian Alps, and the existence of several<br />
postglacial migration routes. At present, endemic plants<br />
along the littoral, among which A. nicaeensis, are seriously<br />
endangered by diverse and serious human impacts. Recent<br />
habitat fragmentation decreases population viability, reducing<br />
population size which induces an extinction vortex. In<br />
addition, rapid colonisation by ligneous species, due to<br />
land-abandonment, induces negative effects on the population<br />
structure and dynamic of A. nicaeensis. On the other<br />
hand, disturbances characterized by intermediate intensity<br />
and frequency, among which cattle grazing for G. ligustica<br />
and fire for A. nicaeensis, favour population persistence.<br />
Despite the higher rarity of A. fabrei, the three known populations<br />
seem not threatened at short-term, in contrast with<br />
A. nicaeensis which needs an urgent planning of habitat<br />
conservation. Also, the natural habitat fragmentation of<br />
G. ligustica, due to paleoecological events, has possibly<br />
induced limited consequences on its genetic diversity.<br />
Within a global change context, it appears necessary to propose<br />
some specific conservation strategies, including the<br />
preservation of intermediate disturbances, habitat conservation,<br />
or an assessment of population history and of their<br />
ecogeographical variability.<br />
Karen BOURGEOIS<br />
<strong>2006</strong><br />
Ecology, biology and conservation<br />
of a <strong>Mediterranea</strong>n endemic seabird<br />
Puffinus yelkouan<br />
Thèse de doctorat en sciences soutenue le 6 décembre <strong>2006</strong><br />
à l’université Paul Cézanne, Aix-Marseille 3, Institut<br />
méditerranéen d’écologie et de paléoécologie (IMEP, UMR-<br />
CNRS 6116, équipe écologie du paysage et biologie de la<br />
conservation, Europôle méditerranéen de l'Arbois, avenue<br />
Philibert, BP 80, 13545 Aix-en-Provence cedex 04, France).<br />
Jury <strong>–</strong> Éric VIDAL (MCF, université Paul Cézanne), P r Thierry TATONI<br />
(université Paul Cézanne), directeur et codirecteur de thèse. Jacob<br />
ecologia mediterranea <strong>–</strong> <strong>Vol</strong>. <strong>32</strong> <strong>–</strong> <strong>2006</strong><br />
Résumés de thèses<br />
GONZALEZ-SOLIS (chargé de recherche, université de Barcelone,<br />
Espagne) et Michel GAUTHIER-CLERC (chargé de recherche HDR, station<br />
biologique de la Tour du Valat), rapporteurs. Bernard DECEUN-<br />
INCK (chargé de mission, BirdLife International/LPO) et Matthieu<br />
LECORRE (MCF, université de la Réunion), examinateurs.<br />
Keywords: breeding biology, breeding habitat selection,<br />
conservation biology, conservation status, introduced<br />
predators, <strong>Mediterranea</strong>n islands, seabird, yelkouan<br />
shearwater.<br />
Procellarids, particularly species of the Manx shearwater<br />
taxonomic complex, are seabirds exhibiting a strong<br />
vulnerability to their habitat disturbance because of their<br />
extreme K demographic strategy. In this complex, the yelkouan<br />
shearwater, Puffinus yelkouan, is a unique case with<br />
its strict endemism to the closed <strong>Mediterranea</strong>n Basin, its<br />
recent elevation to the specific rank and the magnitude of<br />
lacking knowledge of this species. Thus, this thesis general<br />
purpose was to study this still poorly known pelagic<br />
seabird, in order to at least partially fill the knowledge gaps<br />
for this species ecology and biology, and in order to provide<br />
tangible data for management and conservation action<br />
planning for this species.<br />
We firstly reviewed this species population, distribution and<br />
threats throughout its world range. This emphasized the<br />
dramatic lack of reliable and available data concerning the<br />
yelkouan shearwater, yielding to imprecise and overestimated<br />
breeding numbers, to a lack of confirmation for purported<br />
breeding sites, and to the consideration of a stable<br />
population while consistent data suggested population<br />
decline and strong threats. Due to the poorness of existing<br />
data on this species, we secondly developed basic methodologies<br />
to ease its study. Thus, a new sexing method, based<br />
on vocalization analysis, was shown perfectly efficient and<br />
non-invasive in comparison with the classical morphometric<br />
sexing. Moreover, shearwater presence and activity patterns<br />
at colonies were analysed and we demonstrated that<br />
ambient light, breeding cycle and wind speed should be<br />
essential in monitoring and census planning. Both nest-cavity<br />
and colony-site selection analyses, thirdly, allowed to<br />
describe the species ecological preferences, and, above all,<br />
to highlight a particularly low suitable breeding habitat proportion<br />
that is currently occupied by yelkouan shearwaters.<br />
Finally, patterns and impact of feral cat predation were<br />
studied through cat scat analysis and by demographic modelling<br />
(Population Viability Analysis). This predation constitutes<br />
a strong threat for the yelkouan shearwater on our<br />
study site and this analysis revealed an unexpected shearwater<br />
population structure.<br />
These results prioritized cat eradication on the study site<br />
in order to enhance shearwater population dynamics and<br />
to avoid its extinction. Moreover, the abundance of available<br />
and favourable breeding habitat will certainly support<br />
an increase in the shearwater population. By continuing<br />
current monitoring and actions, and by increasing study<br />
area, we will be able to precise the understanding of terrestrial<br />
yelkouan shearwater breeding cycle and to validate<br />
our hypothesis concerning the species population structure.<br />
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