Microbial communities of ultramafic soils in maquis and rainforest at Mont Do,New Caledonia

We analysed variation in microbial community richness and function in soils associated with a fire‐induced vegetation successional gradient from low maquis (shrubland) through tall maquis to rainforest on metal‐rich ultramafic soils at Mt Do, New Caledonia. Random amplified polymorphic DNA fingerprinting was used to determine the extent of genetic relatedness among the microbial communities and indicated that the open and tall maquis microbial communities were more similar to each other than they were to the rainforest community. Sole‐source carbon utilization indicated variation in the microbial communities, again with greater diversity in rainforest soils. Plate counts showed that both rainforest and maquis soils contained bacteria that can grow in the presence of up to 20 mmol L^?1 nickel and 10 mmol L^?1 chromium. Understanding microbial community composition and dynamics in these ultramafic soils may lead to a better understanding of the processes facilitating vegetation succession from shrubland to forest on these high‐metal substrates, and of approaches to successful revegetation following mining for metals including nickel, chromium and cobalt.     

Does soil determine the boundaries of monodominant rain forest with adjacent mixed rain forest and maquis on ultramafic soils in New Caledonia?

Aim To determine the soil characteristics of Nothofagus‐dominated rain forests in an ultramafic region (i.e. soils having high concentrations of metals including Mg, Fe and Ni), and whether soil characteristics may explain the location of monodominant rain forest in relation to adjacent mixed rain forest and maquis (shrub‐dominated vegetation). Location New Caledonia. Methods Soil characteristics were compared among six Nothofagus‐dominated rain forests from a range of altitudes and topographic positions. At four of these sites, comparisons were made with soils of adjacent mixed rain forest and maquis. Results Soil characteristics varied among the monodominant Nothofagus forests, largely due to differences between ultramafic soils and soils influenced by non‐ultramafic intrusions. The soils of all vegetation types had low concentrations of nutrients, particularly P, K and Ca (both total and extractable/exchangeable), and high total concentrations of Ni, Fe, Cr and Mn. There were significant differences between the rain forests and adjacent maquis in soil concentrations of several elements (N, P, Ca, Mg and Mn), more so in surface soils than at depth, but much of this pattern may be caused by effects of vegetation on the soil, rather than of soil on the vegetation. However, there were no significant differences in soil concentrations of any mineral elements between Nothofagus forest and adjacent mixed rain forest. Main conclusions We found no evidence for soil mediation of boundaries of Nothofagus rain forest with mixed rain forest, and little evidence for the boundaries of either forest type with maquis. We suggest that the local abrupt boundaries of these monodominant Nothofagus forests are directly related to temporal factors, such as time since the last wildfire and frequency of wildfire, and that disturbance is therefore a major causal factor in the occurrence of these forests.     

Occurrence of mycorrhizal symbioses in the metal-rich lateritic soils of the Koniambo Massif, New Caledonia

The occurrence of arbuscular mycorrhiza (AM) was surveyed in ten endemic plant species of the Koniambo Massif (New Caledonia) and associated metal-enriched ultramafic soils along a topographic sequence ranging from a plateau at 900 m altitude to a valley at 700 m. In the four different plant formations (Araucaria group on the plateau, ligno-herbaceous maquis, Tristaniopsis maquis and Nothofagus forest in the valley), all plants were consistently colonised by AM fungi, even the sedges Costularia arundinacea, C. nervosa and Lepidosperma perteres and the nickel-hyperaccumulating plant Phyllanthus favieri. Dual (AM and ectomycorrhiza EM) colonisation was observed in the two plant formations dominated by the ectomycorrhizal plants Nothofagus balansae for the forest (site 4) and Tristaniopsis guillainii and T. calobuxus for the Tristaniopsis maquis (site 3). In the soils, there are strong positive correlations between microbial activity, black AM spore abundance and concentrations of available metals indicating the role of the biotic component in the release of metals. These results suggest that these symbioses are important in the adaptation of the endemic plants to these soils, and may be relevant to ecological restoration of the ancient nickel mines.     

Stand structure of the emergent conifer Agathis ovata in forest and maquis, Province Sud, New Caledonia

Abstract. The size structure of the endemic New Caledonian conifer Agathis ovata is reported for sample stands in forest and maquis from three areas on ultramafic substrates in the south of the main island (Grand Terre). In closed forest Agathis ovata is typically represented by a low density of emergent adult trees with only limited evidence of seedling recruitment. In maquis, Agathis ovata is represented by individuals of all sizes, with seedlings and saplings abundant in most sample stands. Preliminary evidence from tree-ring studies indicates that rings may be annual. Estimated diameter growth rate is about 2 mm y^?1 for trees ≥ 10 cm d.b.h., and ring counts suggest tree ages of up to 400 years in maquis and 500 years in forest. Agathis ovata, and three other members of the Araucariaceae found in New Caledonia (Araucaria laubenfelsii, A. montana and A. rulei), are the only tree species which regularly occur scattered in maquis in this way, creating an unusual structural assemblage. No angiosperm tree species show this behaviour. The circumstances under which the Agathis ovata– maquis stands arise and are maintained are the subject of further investigation. Preliminary evidence for tree ages indicates that these stands predate European arrival in New Caledonia and so are not the result of recent increases in the frequency and intensity of human disturbances. The presence of fire scars on many individuals, and location of most stands on slopes and spurs with outcropping laterite (cuirasse), suggests that this assemblage may owe its existence to the interplay of fire regime, topography and rockiness, and a resistance to fire in Agathis ovata which increases with plant size and age.     

Tolerance and induction of tolerance to Ni of arbuscular mycorrhizal fungi from New Caledonian ultramafic soils

The influence of Ni on arbuscular mycorrhizal fungi (AMF) has not been studied yet. We tested the tolerance to Ni of five AMF isolates from New Caledonian ultramafic soils. Spore germination indicated that these isolates were clearly more tolerant to Ni than three other isolates from non-ultramafic soils. They were able to germinate at 30 μg g⁻¹ Ni, whereas spores of the non-ultramafic isolates were totally inhibited at 15 μg g⁻¹ Ni. Among the ultramafic isolates, two were obtained from roots of Ni-hyperaccumulating plants. Their tolerance to Ni was clearly higher than all the other isolates. The proportion of germinated spores of the different isolates in contact with ultramafic soils showed the same tendencies as those observed with Ni solutions. Tolerance to Ni increased when spores were produced from mycorrhiza on plants grown on sand containing 20 μg g⁻¹ Ni, in comparison with those produced on sand without Ni. These results indicate that the tolerance to Ni of AMF spores can be induced by the presence of this metal in the substrate.

Host effects in high ectomycorrhizal diversity tropical rainforests on ultramafic soils in New Caledonia

Tropical rainforests have been thought to have low prevalence and diversity of ectomycorrhizal symbioses. However, to date, tropical regions have been poorly sampled for ectomycorrhizal fungi. Here, we investigated ectomycorrhizal fungal community diversity and the role of host plants in shaping this diversity in three main ultramafic rainforests in New Caledonia, an archipelago renowned for its exceptional plant diversity and recognized as a biodiversity hotspot. Sampling of ectomycorrhizal root tips and fruit bodies in Nothofagus aequilateralis-dominated, Arillastrum gummiferum-dominated and mixed rainforests showed high fungal diversity with, in total, 28 lineages and 311 operational taxonomic units (OTUs), of which 95% might be endemic. We also found that host preference and host density influenced ectomycorrhizal community composition and contributed to the high fungal diversity of New Caledonian rainforests. Finally, the /cortinarius lineage dominated the below- and above-ground communities, which suggests that this lineage plays a central role in ultramafic ecosystems functioning.     

New genera of Copepoda (Poecilostomatoida) from the scleractinian coral Psammocora in New Caledonia

Three new monotypic genera of copepods (Poecilostomatoida) are associated with the hermatypic shallow-water coral Psammocora (Stephanaria) logianensis near Noumea, New Caledonia: in the Anchimolgidae, Lipochaetes extrusus (antenna 4-segmented, endopods absent in legs 3 and 4) and Dumbeana undulatipes (antenna 3-segmcntcd, endopod of leg 3 with formula 0 1; 0–2; 1,11,2; leg 4 endopod with 0 1:1); and in the Rhynchomolgidae; Emunoa proknta (leg 4 endopod with 0 1;II, antenna 4-segmented, mandible witli outer pointed process and inner row of spines). Copepoda (primarily Poecilostomatoida and Siphonostomatoida, but also relatively few Cyclopoida and Harpacticoida) are very frequent associates or parasites of Scleractinia. At present 245 species from 48 scleractinian coral genera are known. Species of these copepod associates, their host genera, and localities, described since (and those not included in) previous publications of the author are listed.     

Tropical dry forests in New Caledonia

Tropical dry forest is the most endangered major vegetation type in the New Caledonia biodiversity hotspot. Vegetation surveys following a transect method used by Gentry were undertaken in two tropical dry forest sites, Ouen-Toro and Pindai, in order to compare species richness, floristic composition, and structure. Pindai contained significantly higher species richness than Ouen-Toro, although there was little difference in forest structure. Tropical dry forest sites in New Caledonia were compared to seven other biodiversity hotspots with tropical dry forest where Gentry's transect method was employed. New Caledonia and other tropical dry forests on islands contain significantly lower species richness than mainland tropical dry forests in biodiversity hotspots. However, New Caledonia contained the highest number of threatened species based on IUCN global conservation categories. Tropical dry forest in New Caledonia appears to be the world's most endangered tropical dry forest based on the extent of forest, number of reserves, and threatened species. Management of tropical dry forests on private and community lands is absolutely imperative to the long-term persistence of this ecosystem.     

Plant extinction in New Caledonia: protection of sclerophyll forests urgently needed

The sclerophyll forests which once extended over the lowlands of the west coast of New Caledonia are now reduced to small fragments representing about 2% (10 000 ha) of their original area. Much of the remaining forests are degraded. Threats to sclerophyll forests come from land clearance, grazing by cattle or deer, and fire. In sclerophyll forests, 223 endemic phanerogam species occur and 59 of these are specific to this forest type. Several of the 59 specific species are known only from a few plants at a single locality and are critically endangered. Pittosporum tanianum sp. nov. became extinct shortly after its discovery in 1988, and becomes the first documented plant extinction in New Caledonia. A further 15 species of New Caledonian plants, not recorded for several decades, are discussed, and it is concluded that between 4 and 9 of them may be extinct. The existing reserves containing sclerophyll forests are inadequate to protect the remaining biodiversity of the forests. Four immediate steps needed to protect sclerophyll forests are (i) restoration of Leprédour Island; (ii) purchase and restoration of selected privately owned forests; (iii) management of publicly owned forest near Népoui; and (iv) ex situ conservation of certain species.     

New records of marine benthic algae from the Lagon Sud-Ouest of New Caledonia, South Pacific

As part of an ongoing project to substantially increase knowledge of the marine algal flora of the French Pacific territory of New Caledonia, a survey of the Nouméa region was conducted that has resulted in the discovery of 41 previously unrecorded species of macroalgae, including 1 Chlorophyta, 1 Phaeophyceae (Heterokontophyta) and 39 Rhodophyta. Among the biogeographically interesting new records are the green macroalga Rhipilia penicilloides N’Yeurt et Keats (previously endemic to the islands of Fiji some 1000 km east of new Caledonia) and the brown alga Cutleria mollis Allender et Kraft (originally described from Lord Howe Island some 1000 km to the south). The red alga Gloiophloea articulata Weber‐van Bosse, known only from its initial discovery in 1928 from the Mascarene Islands in the western Indian Ocean, is now recorded in the deep‐water channels of the Nouméa region of New Caledonia. The widely distributed Indian Ocean species Corynomorpha prismatica (J. Agardh) J. Agardh has its easternmost distribution record from this area, and Dotyella hawaiiensis (Doty et Wainwright) Womersley et Shepley is recorded for the first time outside its central‐Pacific distribution. These new discoveries represent a 12% increase in the total number of species (377) that are reliably known from New Caledonia.     

Testing the assumptions of chronosequences in succession

Many introductory ecology textbooks illustrate succession, at least in part, by using certain classic studies (e.g. sand dunes, ponds/bogs, glacial till, and old fields) that substituted space for time (chronosequence) in determining the sequences of the succession. Despite past criticisms of this method, there is continued, often uncritical, use of chronosequences in current research on topics besides succession, including temporal changes in biodiversity, productivity, nutrient cycling, etc. To show the problem with chronosequence-based studies in general, we review evidence from studies that used non-chronosequence methods (such as long-term study of permanent plots, palynology, and stand reconstruction) to test the space-for-time substitution in four classic succession studies. In several cases, the tests have used the same locations and, in one case, the same plots as those in the original studies. We show that empirical evidence invalidates the chronosequence-based sequences inferred in these classic studies.     

Structural and floristic characteristics of some monodominant and adjacent mixed rainforests in New Caledonia

Nothofagus spp. dominate the upper canopy of some rainforests on ultramafic soils in New Caledonia. These monodominant forests typically occur within, or contiguous with, larger areas of mixed‐canopy rainforest. In this study the structure, diversity and composition of six Nothofagus‐dominated plots were investigated, and comparisons were made with three adjacent mixed rainforest plots. Stand density and basal area (all stems ≥ 1.3 m high) in the Nothofagus plots were in the range 16,056–27,550 stems/ha and 43.1–69.9 m²/ha, respectively. There was no significant difference (P ≥ 0.05) in total stand density or basal area between the paired Nothofagus and mixed rainforests, but there were consistently fewer trees and less basal area of trees ≥ 40 cm d.b.h. in the Nothofagus forests. Species richness, species diversity (Shannon‐Wiener, based on basal area) and equitability (based on basal area) of trees ≥ 20 cm d.b.h. on 0.1 ha Nothofagus plots were in the range 4–17, 0.96–3.76 and 0.45–0.87, respectively. No significant differences (P ≥ 0.05) were recorded in these three parameters between the paired Nothofagus and mixed rainforests, although species diversity was consistently lower in the paired Nothofagus forests. Comparison of dominance by density and basal area indicated that although the uppermost canopy of the Nothofagus forests was dominated by Nothofagus (70–95%), the basal area and density contribution was ≤ 55% except at Col de Yaté (≈ 85%). Analysis of similarity indicated no significant difference in stand composition of trees ≥ 20 cm d.b.h. (following removal of Nothofagus from the data set) between Nothofagus and mixed rainforests using basal area, density or presence‐absence data. It is concluded that the Nothofagus‐dominated forests differ from the adjacent mixed rainforests mainly by (1) dominance of the uppermost canopy, without necessarily dominance of the stand by basal area or density, and (2) the smaller basal area contributed by large trees (all species).     

Anthropology and the Mining Arena in New Caledonia: Issues and Positionalities

In the last 25 years, the mining sector has become an important field of investigation and controversy for anthropologists. As an object, the ‘mine’ itself poses specific problems that make it particularly fertile ground for the exploration of inextricably linked theoretical, methodological, ethical, and political issues. In this paper, I explore the issue of the positionality of anthropologists within the mining arena. The analysis of positionality is taken beyond an individual perspective focusing on ethics, engagement and responsibility, to additionally include discussions of networking, alliance-building and institutionalising processes. I shall begin by dealing with the problems posed by the anthropology of mining and the various perspectives that respond to it. In the second section, I narrow the focus to the case of New Caledonia. In the third section, I present the context and challenges associated with the discussed cases. I portray the cases in question and, in particular, the new arena represented by the National Centre for Technological Research (CNRT) ‘Nickel and its Environment’, an agency established in 2008 to fund research on nickel in New Caledonia. The analysis in terms of a ‘hybrid’ forum of this arena will be complemented by the consideration of the social demand for the anthropology of mining. In the concluding section, the paper outlines options for further research while stressing the need for a balanced, ‘symmetrical’ approach of the multiple actors’ agendas constitutive of the mining arena.     

Life history of the silverside Atherinomorus lacunosus (Atherinidae) in New Caledonia

The abundance, the seasonal variation and the life history of the silverside, Atherinomorus lacunosus , are studied from fish caught in the lagoons around New Caledonia. About 270 nights of fishing were carried out between 1980 and 1983. The silverside is present in most of the fishing hauls but seldom in large quantities. Fish reproduce from September to December at 1 year of age. At this time their size is about 10 cm. Mortality is high and a few individuals can survive a second year and reach 13 cm. Results from other studies indicate that in a less seasonally contrasted environment than the lagoons of New Caledonia, A. lacunosus has several spawning periods during the year. This species is thus able to adjust its phenology to the environmental conditions.     

Distribution and abundance of the dugong in New Caledonia, southwest Pacific

New Caledonia is at the eastern limit of the dugong's range. In June 2003 standardized dugong aerial survey methodology was used to estimate the abundance and distribution of dugongs in the coastal waters of New Caledonia, resulting in a population estimate of 1,814 ± SE 332. This represents the largest concentration of dugongs in Melanesia and one of the largest populations in the world, outside Australia and the Arabian region. Calves comprised 7.2% of the population. The observed density of dugongs was highest in the center and southern part of the west coast of the island but not significantly different from the density on the north west and north east. In the central west region, sightings were associated with a pass in the barrier reef and up to a third of the on‐survey sightings were outside of the barrier reef. The dugong distribution we observed during June 2003 differs from the reported locations of historical hunts in several respects.     

Twenty-one new Polyplectropus species from New Caledonia (Trichoptera: Polycentropodidae)

Twenty-one new Polycentropodidae (Trichoptera) species are described: Polyplectropus aberrus, P. dorsospinus, P. nodyg, P. yndog, P. clavus, P. nathalae, P. millei, P. christinae, P. koueus, P. viklundi, P. hovmoelleri, P. aoupiniensis, P. tenerus, P. angustus, P. curvispinus, P. caledonia, P. piroguensis, P. triangulatus, P. pernodensis, P. taoensis, and P. papei spp. novae, representing the first species records of this family from New Caledonia. A key to males of the New Caledonian Polycentropodidae is provided, and distribution maps are presented for all species.     

江苏省海滩植被演替的研究

江苏省海滩植被可分为滨海盐土植被、盐沼植被及海滩沙生植被三个基本类型。本文论述了这些植被类型的演替规律。滨海盐土植被与盐沼植被的演替,外因于土壤盐分含量递减与有机质含量的递增;海滩沙生植被的演替,外因于土壤沙颗粒大小及其相应的土壤含水量的变化,所以海滩植被演替为外因动态演替。     

Distribution of gymnostoma spp. microsymbiotic frankia strains in new caledonia is related to soil type and to host-plant species

The diversity of the Frankia strains that are naturally in symbiosis with plants belonging to the Gymnostoma genus in New Caledonia was investigated. A direct molecular characterization of DNA extracted from nodules was performed, followed by characterization by restriction fragment length polymorphism (RFLP) of the ribosomal rrs-rrl (16S-23S) intergenic spacer (IGS) polymerase chain reaction (PCR)-amplified region. Seventeen different patterns were identified among the 358 microsymbiotic strains studied in the eight species of host plant present in New Caledonia. This genotypical approach permitted us to show that a large diversity existed among the patterns and that these did not exhibit a strict specificity to any host-plant species comparable with that previously found in the Casuarina and Allocasuarina symbioses in Australia. Despite this lack of specificity, a correspondence analysis nevertheless showed that the distribution of these patterns was related to soil type and to host-plant species. Furthermore, several Frankia strains were exclusively associated with the ultramafic soils.