Infertile landscapes on an old oceanic island: the biodiversity hotspot of New Caledonia

Abstract

The OCBIL theory comprises a set of hypotheses to comprehend the biota of old, climatically buffered, infertile landscapes (OCBILs). Here, we review evidence from the literature to evaluate the extent to which this theory could apply to the biodiversity hotspot of New Caledonia. We present geological, pedological and climatic evidence suggesting how the island might qualify as an OCBIL. The predictions of OCBIL theory are then reviewed in the context of New Caledonia. There is evidence for a high rate of micro-endemism, accumulation of relict lineages, a high incidence of dioecy, myrmecochory and nutritional specializations in plants. New Caledonian vegetation also exhibits several types of monodominant formations that reveal the importance of disturbances on the island. Fires and tropical storms are likely to be important factors that contribute to the dynamic of New Caledonian ecosystems. Although naturally infertile, there is archaeological evidence that humans developed specific horticultural practices in the ultramafic landscapes of New Caledonia. Further comparisons between New Caledonia and other areas of the world, such as South Africa and Southwest Australia, are desirable, to develop the OCBIL theory into a more robust and generalized, testable framework and to determine the most efficient strategies to preserve their outstanding biodiversity.

Intensive cycling of nickel in a New Caledonian forest dominated by hyperaccumulator trees

“…, 2008; Jaffré, 1993; Pillon et al. , 2020). Currently, 99 strong Ni‐hyperaccumulating taxa (>5000 μg g −1 Ni in the foliar dry matter) have been identified from New Caledonia from X‐ray fluorescence (XRF) scanning of herbarium specimens, mostly from the families Cunoniaceae, Phyllanthaceae and Salicaceae (Gei et al.…”

“…, 2016; Jaffré, 1980; Jaffré and L’Huillier, 2010; Pillon et al. , 2010, 2020). There has been little work undertaken in examining the biogeochemical cycling of trace elements, such as Ni, in ultramafic rainforest and its relationship to hyperaccumulator plants.…”

“…Previous research on New Caledonian ultramafic soils has primarily focused on the discovery of Ni hyperaccumulator species, or describing the endemic flora and the factors that have structured it over time (Gei et al, 2020;Isnard et al, 2016;Jaffr e, 1980;Jaffr e and L'Huillier, 2010;Pillon et al, 2010Pillon et al, , 2020. There has been little work undertaken in examining the biogeochemical cycling of trace elements, such as Ni, in ultramafic rainforest and its relationship to hyperaccumulator plants.…”

Unique and shared effects of local and catchment predictors over distribution of hyporheic organisms: does the valley rule the stream?

“…The New Caledonian Archipelago is one of the world's biodiversity hotspots (Myers et al 2000). Beside its heterogeneous topography, the main island (Grande Terre) stands out among islands because of the areal importance of peridotite rocks, which cover about one third of the island (Pillon et al 2021). There is ample evidence that nutrient‐poor and metal‐rich ultramafic soils developing on peridotite have contributed disproportionately to the distinctiveness and distribution of terrestrial plants and animals (Nattier et al 2013, Isnard et al 2016).…”

The Nurse Plant Acacia spirorbis Enriches Ectomycorrhizal Community Composition of a Target Species: Tristaniopsis calobuxus

“…Tropical ecosystems have been the subject of far fewer studies than temperate ecosystems [1], thus our knowledge of the unique New Caledonian ecosystem is extremely new and fragmentary [2,3]. Recent work carried out in these ecosystems revealed the importance of ectomycorrhizal (ECM) symbiosis in New Caledonia (e.g., [4,5]).…”