Structure and genetic diversity of Ixora margaretae an endangered species: a baseline study for
conservation and restoration of natural dry forest of New Caledonia
Verhaegen Daniel
Assoumane Aïchatou
Serret Julien
Noe Sandrine
Favreau Bénédicte
Vaillant Alexandre
Gâteblé Gildas
Pain Anthony
Papineau Christian
Maggia Laurent
Tassin Jacques
Bouvet Jean-Marc
The dry forests of New Caledonia are an exceptional ecosystem because of their numerous endemic
botanical species and their highly diversified fauna of insects, mollusks, reptiles and birds.
Unfortunately, the area of the dry forests has been significantly reduced, mainly by human activities.
Ecological, phenological and genetic analysis of Ixora margaretae, a symbolic species of the
sclerophyll forest, has revealed contrasting traits among natural stands. The division of the natural
range and then the separation of forest islands has greatly reduced the existing genetic variability of
this species. The genetic diversity is strongly structured in genetic clusters which correspond well to
specific ecotypes according to the environmental conditions and the forest types. Furthermore,
genetic analysis of the reproductive and non-reproductive trees as well the half-sib families obtained
by complete protection of mother trees has revealed substantial genetic drift which has resulted in
increased loss of allelic variability. The total consumption of seeds by mainly rats confirms the
observed absence of natural regeneration. All these results show that measures taken to protect the
stands of dry forests will not be enough to maintain sufficient genetic variability of Ixora margaretae
populations in the long term. Assisted regeneration with control of the increase in variability will be
necessary to maintain the biodiversity of the species. The results obtained for Ixora margaretae must
be confirmed with other symbolic species in order to take the necessary measures for the effective
preservation of the dry forests in New Caledonia.
Biodiversity hotspot
sclerophyll forests
endemism
ecology
SSR
gene flow
genetic drift
SSRData.xls
The first sheet concerns the genetic variability obtained with 14 SSR locus SSR on a sample of 245
trees harvested in 7 forests (Nékoro, Tiéa, Tipenga, Pindai, Mepouiri, Ouamenie and Nassirah).
Columns 1 - 4: sample identity; forest name; longitude and latitude of the sample. Columns 5 to 32
SSR genotype. Missing data:-1.The sheet n°2 concerns the genetic variability of 82 progenies with 12
SSR loci (2 loci missing).
The sheet n°3 concerns the genetic variability of 10 mothers trees.
NB mothers n°5 and n°8 have many missing data.