Ornella WEIDELI

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Doctorant
École Pratique des Hautes Études (EPHE)

CRIOBE - Perpignan
USR3278 CRIOBE EPHE-CNRS-UPVD
Bâtiment R-CBETM
58 Avenue Paul Alduy
66860 Perpignan Cedex
France

Email:

Domaines de Recherche:

  • Community Biology
  • Trophic Ecology
  • Special interest in Shark Biology and Ecology

Soutenance de Doctorat | 11 Juin 2020

Titre : Mechanisms of coexistence: A multi-disciplinary investigation of sympatric juvenile reef sharks
Abstract (Short) : In areas of sympatry, closely related and morphologically similar species are expected to occupy different ecological niches in order to avoid competition. However, without knowledge on competitive abilities (e.g. dominance hierarchies) and population characteristics (e.g., growth rates, fitness traits), the origin and the potential effects of niche pattern (segregation and overlap) are unknown. Within the scope of this PhD, juvenile blacktip reef sharks (Carcharhinus melanopterus) and juvenile sicklefin lemon sharks (Negaprion acutidens) were studied at St. Joseph Atoll, Seychelles and at Moorea, French Polynesia. Evidence suggests that juvenile blacktip reef sharks and juvenile sicklefin lemon sharks exhibit fine-scale segregation patterns as a means to avoid competition. In contrast, slight differences in population characteristics were more likely to be caused by prey availability, intraspecific competition, and anthropogenic impacts. This thesis highlights the importance of multi-disciplinary investigations to unveil the underlying mechanisms of coexistence, but future investigations - also including other study sites - are needed to further address these mechanisms.

Sélection de Publications

Biographie

I’m investigating how natural resources (habitat and diet) are partitioned between juvenile blacktip reef sharks, Carcharhinus melanopterus and sicklefin lemon sharks, Negaprion acutidens to elucidate new insights about coexistence, niche segregation patterns, and competition.

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