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Ibanez T.,CNRS European Center for Research and Education in Environmental Geosciences | Ibanez T.,Laboratoire Of Botanique Et Decologie Vegetale Appliquees | Curt T.,IRSTEA | Hely C.,CNRS European Center for Research and Education in Environmental Geosciences
Journal of Vegetation Science | Year: 2013

Questions: How do early secondary successional forest species that grow in savannas differ in their tolerance to surface fires? What are the consequences of these fire tolerances for savanna-forest dynamics and landscape management? Location: Anthropogenic savannas in the New Caledonian biodiversity hotspot (SW Pacific). Methods: We estimated the range of fire intensity in New Caledonian savannas using field survey of fuels and the BehavePlus fire behaviour model. Within the predicted range of fire line intensity, we assessed theoretical fire injury to the cambium and crown for 11 species: the dominant tree of New Caledonian savannas (Melaleuca quinquenervia) and early secondary successional forest species. Using empirical models, for each species we estimated cambium damage from depth of necrosis (as a function of fire line intensity and fire residence time) and bark thickness, and crown damage from scorch height (as a function of fire line intensity) and tree height. We compared bark thickness and tree height increment patterns among species as well as species potential fire tolerance. Results: The 11 species had very contrasting capacity to avoid fire injury to the bole cambium due to differences in bark investment patterns, but were all very exposed to scorching and crown injury. Overall, most of sampled individuals are likely top-killed by low intensity fires (<1000 kW·m-1), which are frequent according to our simulations. Conclusions: The early secondary successional forest species growing in New Caledonian savannas are poorly adapted to fire, in comparison with literature on worldwide trees in savannas. As a result, their juveniles are unlikely to reach adult size in fire-prone areas. Restoration using the most fire-tolerant species and fire prevention may be complementary strategies to manage such tropical landscapes in order to conserve biodiversity and ecosystem services. We used a combination of allometric relationships and models of fire behaviour with fire injuries to assess how savanna and early secondary successional forest species differ in their tolerance to fires. We showed that the tolerance of these species to fire is highly variable and that the investment in bark thickness seems to be the prevailing trait that differentiates them. © 2012 International Association for Vegetation Science.

Ibanez T.,IAC | Ibanez T.,Laboratoire Of Botanique Et Decologie Vegetale Appliquees | Munzinger J.,IRD Montpellier | Munzinger J.,Laboratoire Of Botanique Et Decologie Vegetale Appliquees | And 10 more authors.
Applied Vegetation Science | Year: 2014

Aims: To describe the structural and floristic diversity of New Caledonian mixed tropical rain forest and investigate its environmental determinants. Location: New Caledonia (SW Pacific), a biodiversity hotspot. Methods: Structural (stem density, basal area) and floristic characteristics (composition, species richness and dissimilarity) were investigated along environmental gradients (elevation, rainfall and slope) on different substrates (ultramafic and non-ultramafic) through the New Caledonian Plant Inventory and Permanent Plots Network (NC-PIPPN, 201 plots each measuring 20 m x 20 m). Results: A total of 28,640 trees (DBH ≥5 cm) belonging to 749 species, 240 genera and 92 families were inventoried in the NC-PIPPN. The New Caledonian mixed rain forest studied was characterized as having high stem density, basal area and species richness, and many small stems (60% of the trees <10 cm DBH and almost a quarter of species did not exceed this threshold). More than one-third of the species were rare (i.e. inventoried in less than three plots or represented by fewer than three individuals) in the plot network and floristic dissimilarity was high (Bray-Curtis index >0.70). The presence of ultramafic (UM) and non- ultramafic substrates (non-UM) combined with altitudinal and rainfall gradients were the main drivers of floristic dissimilarity, whereas the effect of geographic distance between the plots was surprisingly low. Floristic dissimilarity was very high between UM and non-UM substrates from species up to family level. About 75% of the species occurred on a single substrate type. The mixed rain forest on UM and non-UM substrates differed in floristic composition but not in structure. Conclusions: NC-PIPPN proved to be an effective tool for investigating the woody species richness of New Caledonia as containing ca. 46% of its non-herbaceous species. However, the network's design, and more specifically its small plots, restricts its capacity to capture beta diversity and forest structure. High species richness and floristic dissimilarity confirm that New Caledonian mixed rain forest is exceptionally rich. The New Caledonian Plant Inventory and Permanent Plot Network (NC-PIPPN) offers new opportunities to investigate structural and floristic diversity of tropical rainforest in the biodiversity hotspot of New Caledonia. Through the study of 201 plots and the inventory of 28,640 trees belonging to 749 species, 240 genera and 92 families we explored the environmental and spatial drivers of rainforest diversity. © 2013 International Association for Vegetation Science.

Donovan B.J.,Donovan Scientific Insect Research | Munzinger J.,Laboratoire Of Botanique Et Decologie Vegetale Appliquees | Pauly A.,Institute Royal des science Naturelles des Belgique | McPherson G.,Missouri Botanical Garden
Annals of the Missouri Botanical Garden | Year: 2013

The flower-visiting records for the 43 species of bees considered to be native to New Caledonia show that females of 21 species visited 116 native species of plants in 69 genera and 41 families, and the bees were documented to carry pollen from 64 species and possibly four more. The plant families with the greatest number of species documented for visits by female bees were, in descending order: Myrtaceae (21), Dilleniaceae (10), Cunoniaceae (nine), Araliaceae (seven), Fabaceae (seven, encompassing the Caesalpinioideae, Mimosoideae, and Papilionoideae), Goodeniaceae (five), Proteaceae (five), Apocynaceae (four), Sapindaceae (four), and remaining families with one to three species. Females of six and possibly one more species carried pollen from each of Dilleniaceae and Myrtaceae, six carried pollen from Araliaceae, five from Goodeniaceae, four and possibly one more from Cunoniaceae, four from each of Fabaceae and Sapindaceae, and none to three from the remaining 34 families observed. For introduced plants, female bees of 12 species visited 54 species in 43 genera among 19 plant families and were documented to carry pollen from 31 and possibly one more species. For introduced plants, families with the highest number of species visited by female bees, in descending order, were: Asteraceae (12); Fabaceae (eight); Verbenaceae (seven); and Euphorbiaceae, Myrtaceae, and Solanaceae each with three. The remaining 13 families had either one or two species visited by bees. Females of seven species of bees carried pollen from Fabaceae, six from Asteraceae, three each from Myrtaceae and Solanaceae, and none to "2 + 1?" (two or possibly three) from remaining families. Only half a dozen species of native bees can be considered to be common, in that they can be expected to be observed reasonably regularly on a range of flowers. The ubiquitous introduced honey bee Apis mellifera L. and its constant foraging for nectar and pollen on a very wide range of flowers may outcompete many species of native bees, potentially reducing their numbers, and consequently obscuring their relationships with the flora.

Munzinger J.,Laboratoire Of Botanique Et Decologie Vegetale Appliquees | Munzinger J.,IRD Montpellier | Swenson U.,Swedish Museum of Natural History
Australian Systematic Botany | Year: 2015

The genus Pycnandra Benth. (Sapotaceae, Chrysophylloideae) is endemic to New Caledonia with 66 known species and is subdivided in six subgenera. We have earlier revised four of these subgenera and here continue with P. subgenus Leptostylis and describe P. subgenus Wagapensia. Subgenus Leptostylis is distinguished mainly by its opposite leaves and four sepals, and includes eight species, of which two are described as new (P. amplexicaulis and P. sclerophylla). Two species, P. longiflora and P. micrantha, are assumed extinct because extensive fieldwork has not been able to relocate the plants. Variation in leaf morphology was observed in Leptostylis gatopensis, which is by consequence considered as synonym of Pycnandra filipes. Two additional taxa belong to this subgenus, but cannot presently be described because sufficient fertile material is unavailable. Subgenus Wagapensia is monotypic and readily distinguished on the basis of its subverticillate leaves and leafy shoots usually borne beneath apical clusters of leaves, a character common in Sapotaceae but unique in Pycnandra. The members of P. subgenus Leptostylis occur mainly in maquis vegetation or sclerophyllous forests on ultramafic soil, but three taxa are confined to calcareous areas. Mining activities in New Caledonian ultramafic areas are extensive and because some of these species are naturally rare, IUCN Red List assessments are provided to all species. Pycnandra grandifolia and P. wagapensis are assigned the IUCN status Vulnerable, P. amplexicaulis and P. sclerophylla are considered Endangered, P. filipes subspecies multiflora and P. goroensis are considered to be Critically Endangered, whereas P. micrantha and P. longiflora appear to be extinct. © CSIRO 2015.

Morat P.,French Natural History Museum | Jaffre T.,Laboratoire Of Botanique Et Decologie Vegetale Appliquees | Tronchet F.,French Natural History Museum | Munzinger J.,Laboratoire Of Botanique Et Decologie Vegetale Appliquees | And 8 more authors.
Adansonia | Year: 2012

The floristic inventory presented here comprises the evolving computerised database Florical (http://www.botanique.nc/herbier/florical). As of the date of publication, it lists all native vascular plant species (as well as infraspecific taxa) present in the territory of New Caledonia, whether validly published or in press, along with their basionym, organised according to the most recent classifications systems (APG III 2009 for the angiosperms, Smith et al. [2006] for the ferns and lycophytes, and Mabberley [2009] for the gymnosperms), accompanied by their status (native or endemic) and the various vegetation types in which they occur. After a brief historical review of our knowledge of New Caledonian botany, the characteristics (richness, composition and endemism) of the different taxonomic groups (ferns and lycophytes, gymnosperms and then angiosperms - mono- and dicotyledons) are analyzed, followed by an assessment of the distribution of these groups among the vegetation types. The vascular flora of New Caledonia is characterised by its high level of richness (3371 species, including 3099 for the flowering plants alone), despite the absence or under-representation of some taxa that are abundantly represented elsewhere in the tropics, and especially by its remarkable distinctiveness (with endemism at the species level reaching 74,7%, and 77.8% for the flowering plants). The flora stands out by the presence of several relictual taxa and a high level of speciation among certain groups, despite the fact that the island was re-colonised relatively recently following the total submersion of its much older basement during the Paleocene and the Oligocene. Details of the measures taken to conserve this extraordinary natural heritage show that only 3.4% of the territory's total surface area is effectively protected. Despite the undeniable progress made in recent years by the authorities concerned, significant work remains to be done, especially in the northern Province. © Publications Scientifiques du Muséum national d'Histoire naturelle.

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