References of "Boisson, Sylvain"
     in
Bookmark and Share    
Full Text
Peer Reviewed
See detailHow to increase species diversity in phytostabilization strategies near Lubumbashi (D.R.C.)
Boisson, Sylvain ULg; Collignon, Julien ULg; Le Stradic, Soizig ULg et al

Conference (2013, October 08)

Copper contamination of soils represents a threat to natural areas and to human health. Phytostabilization, i.e using plants to immobilize contaminants, represents a well-known technology to hemper heavy ... [more ▼]

Copper contamination of soils represents a threat to natural areas and to human health. Phytostabilization, i.e using plants to immobilize contaminants, represents a well-known technology to hemper heavy metals spread across landscapes. In Katanga (Congo D.R.), Microchloa altera was recently identified as a candidate species to stabilize copper in soil. This grass naturally tolerates and accumulates high copper concentrations and belongs to the typical copper flora of Katanga. However more than 600 species compose this flora and other grasses may be used in phytostabilisation strategies. But little is known about the phenology reproductive strategy and demography of these species, which makes their use in current phytostabilization strategies difficult. The present study aims to characterize the reproduction capacity of seven other dominant grass species for future phytostabilisation tests. A total of 67 quadrats (1m²) were randomly placed across three sites. At two periods over the fruiting season, three inflorescences per species per quadrat were collected in order to estimate the number of spikes, spikelets and viable seeds. All species have sexual reproductive strategy and spikelets number presents little variation between populations. Three species are very common (Andropogon shirensis, Loudetia simplex and Eragrostis racemosa) and represent potential candidates to increase species diversity in phytostabilization strategies in Katanga. Further research, including germination tests and phytostabilization tests in situ, is planned in a near future. [less ▲]

Detailed reference viewed: 35 (7 ULg)
Full Text
Peer Reviewed
See detailPlant ecological niche distribution along heavy metal gradients
Boisson, Sylvain ULg; Monty, Arnaud ULg; Seleck, Maxime ULg et al

Conference (2013, June 26)

Why species do not occur everywhere? The concept of ecological niche is central to understand relationships among biotic/abiotic factors and species distribution. Gradients of environmental stress ... [more ▼]

Why species do not occur everywhere? The concept of ecological niche is central to understand relationships among biotic/abiotic factors and species distribution. Gradients of environmental stress associated to interspecific interactions generate testable patterns of specie’s response curves. Distribution of response curves have been seldom tested along toxicity gradient, in contrast to resource gradients. On Katangan copper hills (south R.D.C.), natural copper and cobalt concentrations span a large range: 2 - 1000 mg kg-1 for cobalt and 30 - 10 000 mg kg-1 for copper. In this study, we evaluate three hypotheses related to niche distributions and shapes along metal toxic gradients: (1) Species optima are uniformly distributed over copper-cobalt gradient. (2) Realized niche width varies in relation to the niche optimum along copper and cobalt gradient. (3) Absolute values of skewness coefficient are higher when plant species optima are in the extremes of cobalt gradient with a niche tails toward mesic conditions. Realized niches of 80 taxa were modeled with general additive models (GAM) using presence/absence data in 172 1m² plots. Niche optima, niche widths and skewness coefficients were estimated from species response curves. The three hypotheses were globally validated. Three groups of species were distinguished according to their optima position along metal gradient with packed optima on intermediate concentrations suggesting higher interspecific competition in low metal concentrations. Niche width increased with metal concentrations. Highest metal tolerant plant species had broader niches. Skewness coefficient was inversely related to niche optima positions. Our study demonstrates that species distribution pattern on toxicity gradient presents similarities with resource gradient. Broad realized amplitude of species adapted to high levels of copper cobalt concentrations suggests that fundamental niche of specialist metallophytes may be larger than expected. This should be further tested in controlled conditions in association to competition tests. [less ▲]

Detailed reference viewed: 74 (26 ULg)
See detailCopperflora.org - website
Boisson, Sylvain ULg; Lebrun, Julie ULg; Seleck, Maxime ULg et al

Textual, factual or bibliographical database (2012)

This website is intended as a place of exchange for scientists and mine managers interested in the conservation, the restoration and the taxonomy of the copper-cobalt flora.

Detailed reference viewed: 33 (16 ULg)
Full Text
See detailModelling realized niche of metallophyte species along copper and cobalt gradients on Katanga copper hills
Boisson, Sylvain ULg; Seleck, Maxime ULg; Guillaume, Arielle et al

Poster (2012, February 10)

In South Central Africa were identified more than 650 plant species tolerant to heavy metals, several of which endemic to Katanga and critically endangered by mining activities. These metallophyte are ... [more ▼]

In South Central Africa were identified more than 650 plant species tolerant to heavy metals, several of which endemic to Katanga and critically endangered by mining activities. These metallophyte are distributed over a hundred hills containing high copper and cobalt concentrations (20 to 10000 mg/kg for copper and 2 to 1000 mg/kg for cobalt). To understand the response of metallophyte to heavy metals, the ecological niches of 80 cupro-cobaltophytes were modeled with general additive models (GAM). Results show that (1) three groups of species were identified according to their optimum along a metal concentrations gradient and (2) a positive relationship exists between niche amplitude and optimum copper concentration. [less ▲]

Detailed reference viewed: 48 (14 ULg)
Full Text
See detailContribution à la conservation de la flore cupro-cobalticole endémique du Katanga (R.D.C.) : Conservation en banque de graines et régénération d'espèces métallicoles
Boisson, Sylvain ULg

Master's dissertation (2011)

Metallophytes are plants that represent the biodiversity of metal-rich soils. Some of them are able to accumulate high metal concentrations: metal hyperaccumulators plants. In Katanga (RD Congo), 32 ... [more ▼]

Metallophytes are plants that represent the biodiversity of metal-rich soils. Some of them are able to accumulate high metal concentrations: metal hyperaccumulators plants. In Katanga (RD Congo), 32 species have been identified as copper-cobalt endemic but mining activities are still a threat to outcrop ecosystems. We must characterize native environmental parameters (realized niche) and the full range of environmental conditions in culture (fundamental niche) to conserve, preserve and restore these ecosystems. Six representative species of the natural copper gradient were selected after soil-species data analyses (Crepidorhopalon perennis, Crotalaria cobalticola, Gladiolus ledoctei, Haumaniastrum robertii, Lopholaena deltombei and Sopubia mannii). The study determined their behavior (germination, survival) and their development (vegetative measures) on one group of natural soil (from three copper gradients of Fungurume V hill), two groups of artificially contaminated soils with incremental doses (copper sulfate and copper hydroxycarbonate: 500, 2000 and 5000 mg.kg-1) and one uncontaminated soil (control) by two types of plant establishment (direct seeding and transplant from Petri dishes). The results depend on species habitat and show that four of these species can grow on uncontaminated soil in the early stages of growth. In addition, the seed bank (in Faculty of Agronomy - University of Lubumbashi) management (cleaning, updating and germination tests of accessions) was maintained using standard methods. The results of germination tests demonstrated the effectiveness of some conservation methods and helped to provide recommendations for the methodology. [less ▲]

Detailed reference viewed: 161 (31 ULg)