Species distribution models (SDMs) represent a widely acknowledged tool to identify priority areas on the basis of occurrence data and environmental factors. However, high levels of topographical and ...climatic micro-variation are a hindrance to reliably modelling the distribution of narrow-endemic species when based on classic occurrence and climate datasets. Here, we used high-resolution environmental variables and occurrence data obtained from dedicated field studies to produce accurate SDMs at a local scale. We modelled the potential current distribution of 23 of the 25 rarest species from Mount Kaala, a hotspot of narrow-endemism in New Caledonia, using occurrence data from two recent sampling campaigns, and eight high-resolution (10 m and 30 m) environmental predictors in a Species Distribution Modelling framework. After a first sampling operation, we surveyed six additional areas containing, overall, 13 of the 20 species modelled at this stage, to validate our projections where the highest species richness levels were predicted. The ability of our method to define conservation areas was largely validated with an average 84% of predicted species found in the validation areas, and additional data collected enabling us to model three more species. We therefore identified the areas of highest conservation value for the whole of Mount Kaala. Our results support the ability of SDMs based on presence-only data such as MaxEnt to predict areas of high conservation value using fine-resolution environmental layers and field-collected occurrence data in the context of small and heterogeneous systems such as tropical islands.
Agromining: Farming for Metals in the Future? van der Ent, Antony; Baker, Alan J. M; Reeves, Roger D ...
Environmental science & technology,
04/2015, Letnik:
49, Številka:
8
Journal Article
Recenzirano
Odprti dostop
Phytomining technology employs hyperaccumulator plants to take up metal in harvestable plant biomass. Harvesting, drying and incineration of the biomass generates a high-grade bio-ore. We propose ...that “agromining” (a variant of phytomining) could provide local communities with an alternative type of agriculture on degraded lands; farming not for food crops, but for metals such as nickel (Ni). However, two decades after its inception and numerous successful experiments, commercial phytomining has not yet become a reality. To build the case for the minerals industry, a large-scale demonstration is needed to identify operational risks and provide “real-life” evidence for profitability.
New Caledonia is a global biodiversity hotspot facing extreme environmental degradation. Given the urgent need for conservation prioritisation, we have made a first-pass quantitative assessment of ...the distribution of Narrow Endemic Species (NES) in the flora to identify species and sites that are potentially important for conservation action. We assessed the distributional status of all angiosperm and gymnosperm species using data from taxonomic descriptions and herbarium samples. We characterised species as being NES if they occurred in 3 or fewer locations. In total, 635 of the 2930 assessed species were classed as NES, of which only 150 have been subjected to the IUCN conservation assessment. As the distributional patterns of un-assessed species from one or two locations correspond well with assessed species which have been classified as Critically Endangered or Endangered respectively, we suggest that our distributional data can be used to prioritise species for IUCN assessment. We also used the distributional data to produce a map of "Hotspots of Plant Narrow Endemism" (HPNE). Combined, we used these data to evaluate the coincidence of NES with mining activities (a major source of threat on New Caledonia) and also areas of conservation protection. This is to identify species and locations in most urgent need of further conservation assessment and subsequent action. Finally, we grouped the NES based on the environments they occurred in and modelled the habitat distribution of these groups with a Maximum Entropy Species Distribution Model (MaxEnt). The NES were separable into three different groups based primarily on geological differences. The distribution of the habitat types for each group coincide partially with the HPNE described above and also indicates some areas which have high habitat suitability but few recorded NES. Some of these areas may represent under-sampled hotspots of narrow endemism and are priorities for further field work.
Diversispora cerifera
and
Diversispora succinacia
are new arbuscular mycorrhizal fungal species that have been isolated and propagated from spores extracted from rhizosphere soils of native ...vegetation that had naturally established from seeds on a nickel mine tailing test basin in New Caledonia. Interestingly, these species were not recorded from ultramafic soils of maquis vegetation endemic to New Caledonia surrounding the tailing basin. In greenhouse trap and single-species cultures, the fungi produced numerous spores, which were formed terminally or intercalary on subtending hyphae. Spores of
D. cerifera
are white-yellow with a waxy appearance and 70–100–120 µm in diameter; spores of
D. succinacia
are translucent, amber in color, and 60–80–110 µm in diameter; both species have three spore wall layers. A phylogenetic analysis placed
D. cerifera
in a clade sister to
D. succinacia
. The same analysis showed that the sister species of
D. succinacia
is
D. sabulosa
.
When referring to fruit-piercing moths, the genus
, and more specifically
(Linneaus)
is cited as a worldwide crop pest. Damages associated with this pest are substantial on more than 100 fruit ...species, wherever it is encountered. In New Caledonia, the once occasional pest has become a serious threat to the current fruit arboriculture. Particularly devastating during outbreak periods, it has become an urgent need to find a suitable solution able to support farmers in the ecological transition of our agricultural models. This review proposes a synthesis of the existing data and publications on
, worldwide and especially in New Caledonia, with recent observations. The assessment of this knowledge and the dynamics of the species in the territory of New Caledonia provide key information for a better prospect of adapted solutions.
Aims
This study aimed to establish elemental profiles and to spatially resolve the elemental distribution in five New Caledonian woody Ni hyperaccumulator plant species (
Geissois pruinosa
var
. ...pruinosa
,
Homalium francii
,
Hybanthus austrocaledonicus
,
Psychotria gabriellae
, and
Pycnandra acuminata
) originating from the Cunoniaceae, Salicaceae, Violaceae, Rubiaceae, and Sapotaceae families respectively.
Methods
Using synchrotron-based micro-X-ray Fluorescence (μXRF) imaging of different plant tissues, from the roots to the shoots and reproductive organs, this study aimed to clarify how distribution patterns of nickel, and other physiologically relevant elements, differ between these species.
Results
The results show that the tissue-level and cellular-level distribution of nickel in
P. gabriellae, H. austrocaledonicus, G. pruinosa
var
. pruinosa,
and
H. francii
conform with the majority of studied Ni hyperaccumulator plant species globally, including (temperate) herbaceous species, with localization mainly in epidermal cells and phloem bundles. However,
P. acuminata
has nickel-rich laticifers, which constitute an independent network of cells that is parallel to the vascular bundles and are the main sink for nickel.
Conclusions
Synchrotron-based micro-X-ray Fluorescence (μXRF) is a powerful method for investigating how metal hyperaccumulation influences acquisition and spatial distribution of a wide range of elements. This non-invasive method enables investigation into the in vivo distribution of multiple elements and the structure and organisation of cells (e.g. laticifers).
We assess relationships among 192 species in all 12 monocot orders and 72 of 77 families, using 602 conserved single-copy (CSC) genes and 1375 benchmarking single-copy ortholog (BUSCO) genes ...extracted from genomic and transcriptomic datasets. Phylogenomic inferences based on these data, using both coalescent-based and supermatrix analyses, are largely congruent with the most comprehensive plastome-based analysis, and nuclear-gene phylogenomic analyses with less comprehensive taxon sampling. The strongest discordance between the plastome and nuclear gene analyses is the monophyly of a clade comprising Asparagales and Liliales in our nuclear gene analyses, versus the placement of Asparagales and Liliales as successive sister clades to the commelinids in the plastome tree. Within orders, around six of 72 families shifted positions relative to the recent plastome analysis, but four of these involve poorly supported inferred relationships in the plastome-based tree. In Poales, the nuclear data place a clade comprising Ecdeiocoleaceae+Joinvilleaceae as sister to the grasses (Poaceae); Typhaceae, (rather than Bromeliaceae) are resolved as sister to all other Poales. In Commelinales, nuclear data place Philydraceae sister to all other families rather than to a clade comprising Haemodoraceae+Pontederiaceae as seen in the plastome tree. In Liliales, nuclear data place Liliaceae sister to Smilacaceae, and Melanthiaceae are placed sister to all other Liliales except Campynemataceae. Finally, in Alismatales, nuclear data strongly place Tofieldiaceae, rather than Araceae, as sister to all the other families, providing an alternative resolution of what has been the most problematic node to resolve using plastid data, outside of those involving achlorophyllous mycoheterotrophs. As seen in numerous prior studies, the placement of orders Acorales and Alismatales as successive sister lineages to all other extant monocots. Only 21.2% of BUSCO genes were demonstrably single-copy, yet phylogenomic inferences based on BUSCO and CSC genes did not differ, and overall functional annotations of the two sets were very similar. Our analyses also reveal significant gene tree-species tree discordance despite high support values, as expected given incomplete lineage sorting (ILS) related to rapid diversification. Our study advances understanding of monocot relationships and the robustness of phylogenetic inferences based on large numbers of nuclear single-copy genes that can be obtained from transcriptomes and genomes.
Relationships between the trace-elements (TE) content of plants and associated soil have been widely investigated especially to understand the ecology of TE hyperaccumulating species to develop ...applications using TE phytoextraction. Many studies have focused on the possibility of quantifying the soil TE fraction available to plants, and used bioconcentration (BC) as a measure of the plants ability to absorb TE. However, BC only offers a static view of the dynamic phenomenon of TE accumulation. Accumulation kinetics are required to fully account for TE distributions in plants. They are also crucial to design applications where maximum TE concentrations in plant leaves are needed. This paper provides a review of studies of BC (i.e. soil-plant relationships) and leaf-age in relation to TE hyperaccumulation. The paper focuses of Ni and Mn accumulators and hyperaccumulators from New Caledonia who were previously overlooked until recent Ecocatalysis applications emerged for such species. Updated data on Mn hyperaccumulators and accumulators from New Caledonia are also presented and advocate further investigation of the hyperaccumulation of this element. Results show that leaf-age should be considered in the design of sample collection and allowed the reclassification of Grevillea meisneri known previously as a Mn accumulator to a Mn hyperaccumulator
The ovules and seeds of most angiosperm groups are enclosed by two integuments, whose evolutionary origins are considerably separated in time, as the inner integument arose over 300 million years ago ...(MYA) in an ancestor of all living seed plants, while the outer integument arose, perhaps as recently as 164 MYA, in an ancestor of all living angiosperms. Studies of the model angiosperm
indicate that the mechanisms of development of the inner and outer integuments depend on largely different sets of molecular players. However, it was not known, in most cases, whether these differences were already present in early flowering plants, or arose later in the
lineage. Here, we analyze the expression patterns of integument regulators in
, the likely sister to all other living angiosperms. The data obtained indicate that regulators of the YABBY, KANADI, and homeodomain-leucine zipper class III transcription factor families have largely conserved their integument-specific expression profiles in the
and
lineages since the most recent common ancestor (MRCA) of living angiosperms. We identified only one case, involving the paralogous genes
and
, in which integument-specific expression patterns had clearly diverged between
and
. We use the data obtained to partially reconstruct molecular mechanisms of integument development in the MRCA of living angiosperms and discuss our findings in the context of alternative hypotheses for the origin of the angiosperm outer integument.
The discovery of nickel hyperaccumulation, in Pycnandra acuminata, was the start of a global quest in this fascinating phenomenon. Despite recent advances in the physiology and molecular genetics of ...hyperaccumulation, the mechanisms and tolerance of Ni accumulation in the most extreme example reported to date, P. acuminata, remains enigmatic. We conducted a hydroponic experiment to establish Ni tolerance levels and translocation patterns in roots and shoots of P. acuminata, and analyzed elemental partitioning to gain insights into Ni regulation. We combined a phylogeny and foliar Ni concentrations to assess the incidence of hyperaccumulation within the genus Pycnandra. Hydroponic dosing experiments revealed that P. acuminata can resist extreme Ni concentrations in solution (up to 3,000 µM), and dosing at 100 µM Ni was beneficial to growth. All plant parts were highly enriched in Ni, but the latex had extreme Ni concentrations (124,000 µg g-1). Hyperaccumulation evolved independently in only two subgenera and five species of the genus Pycnandra. The extremely high level of Ni tolerance is posited to derive from the unique properties of laticifers. The evolutionary and ecological significance of Ni hyperaccumulation in Pycnandra is discussed in light of these findings. We suggest that Ni-rich laticifers might be more widespread in the plant kingdom and that more investigation is warranted.
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