Hautekeete N.-C.,Lille University of Science and Technology |
Frachon L.,Lille University of Science and Technology |
Frachon L.,French National Institute for Agricultural Research |
Frachon L.,French National Center for Scientific Research |
And 6 more authors.
Diversity and Distributions
Aim: At a global scale, biodiversity changes are mainly driven by extinction, resulting in an overall decrease in species richness. At regional and local scales, although immigration often (over)compensates for local extinction, biodiversity changes have no clear trends. We tested the hypotheses that (1) at both regional and local scales, biodiversity changes result from the differential dynamics of local extinction and immigration, ultimately leading to increases in biodiversity following periods of transient surplus or deficit and (2) habitats are differentially affected by human activities, resulting in contrasting trends and dynamics that together shape the regional biodiversity budget. Location: Northern France and Belgian Flanders, north-western Europe. Methods: We analysed changes in plant species richness over one century in two adjacent and densely populated regions. Because local to regional changes are expected to be driven by species-environment interactions, and because species ecology and environmental change are largely embodied by the habitat, we assessed biodiversity budgets according to the type of habitat. Results: We observed major changes in species composition at the regional scale with about one of every five to six species becoming regionally extinct or newly naturalized. Immigration offset or exceeded losses, with local extinctions generally preceding gains. Overall, regional dynamics were driven by contrasting changes in a few habitat types, with either local extinction or immigration predominating. Transient biodiversity surpluses or deficits were observed at the regional scale and in certain habitat types. Main conclusions: Including habitat types bridges the gap between regional and local studies and provides a more accurate assessment of the biodiversity budget: integrating habitat type into regional analyses or meta-analyses can lead future research towards the understanding of the determinisms of biodiversity change across spatial scales. © 2014 John Wiley & Sons Ltd. Source
Godefroid S.,National Botanic Garden of Belgium |
Godefroid S.,Vrije Universiteit Brussel |
Godefroid S.,Roosevelt University |
Piazza C.,Conservatoire botanique national de Corse |
And 18 more authors.
Reintroduction of native species has become increasingly important in conservation worldwide for recovery of rare species and restoration purposes. However, few studies have reported the outcome of reintroduction efforts in plant species. Using data from the literature combined with a questionnaire survey, this paper analyses 249 plant species reintroductions worldwide by assessing the methods used and the results obtained from these reintroduction experiments. The objectives were: (1) to examine how successful plant species reintroductions have been so far in establishing or significantly augmenting viable, self-sustaining populations in nature; (2) to determine the conditions under which we might expect plant species reintroductions to be most successful; (3) to make the results of this survey available for future plant reintroduction trials. Results indicate that survival, flowering and fruiting rates of reintroduced plants are generally quite low (on average 52%, 19% and 16%, respectively). Furthermore, our results show a success rate decline in individual experiments with time. Survival rates reported in the literature are also much higher (78% on average) than those mentioned by survey participants (33% on average). We identified various parameters that positively influence plant reintroduction outcomes, e.g., working in protected sites, using seedlings, increasing the number of reintroduced individuals, mixing material from diverse populations, using transplants from stable source populations, site preparation or management effort and knowledge of the genetic variation of the target species. This study also revealed shortcomings of common experimental designs that greatly limit the interpretation of plant reintroduction studies: (1) insufficient monitoring following reintroduction (usually ceasing after 4 years); (2) inadequate documentation, which is especially acute for reintroductions that are regarded as failures; (3) lack of understanding of the underlying reasons for decline in existing plant populations; (4) overly optimistic evaluation of success based on short-term results; and (5) poorly defined success criteria for reintroduction projects. We therefore conclude that the value of plant reintroductions as a conservation tool could be improved by: (1) an increased focus on species biology; (2) using a higher number of transplants (preferring seedlings rather than seeds); (3) taking better account of seed production and recruitment when assessing the success of reintroductions; (4) a consistent long-term monitoring after reintroduction. © 2010 Elsevier Ltd. Source
Leducq J.-B.,Lille University of Science and Technology |
Gosset C.C.,Lille University of Science and Technology |
Poiret M.,Lille University of Science and Technology |
Hendoux F.,Conservatoire Botanique National de Bailleul |
And 2 more authors.
Homomorphic self-incompatibility (SI) evolved in many plant families to enforce selfing avoidance, and is controlled by a single multiallelic locus (the S-locus). In a fragmented landscape, strong variation in population size and in local density is expected to cause strong variation in allelic diversity at the S-locus, which could generate an Allee effect on female reproductive success by constraining compatible pollen availability. In this experimental study, we aimed at detecting this SI-specific Allee effect (or S-Allee effect) in the endangered species Biscutella neustriaca. We demonstrated the occurrence of a SI mating system in the species and determined compatibility relationships among genotypes through a large set of controlled pollinations. For the experiment, we chose three different pollen receptor genotypes, each compatible with respectively 100, 75 and 25% of four other genotypes, which constituted the pollen sources. We placed different ramets of each receptor at different distances from the pollen sources to control for pollen limitation due to low local density, and we measured the seed set on each receptor plant three times consecutively. Analyses performed with generalized linear mixed models showed that both the distance to the pollen sources and the mate availability due to SI had a significant effect on seed set, with a strong reduction observed when mate availability was limited to 25%. Our results suggest that pollen limitation due to a restriction in compatible mate availability could occur in small or scattered populations exhibiting low allelic diversity at the S-locus. © 2010 Springer Science+Business Media B.V. Source
Vanden Broeck A.,Research Institute for Nature and Forest INBO |
Van Landuyt W.,Research Institute for Nature and Forest INBO |
Cox K.,Research Institute for Nature and Forest INBO |
De Bruyn L.,Research Institute for Nature and Forest INBO |
And 8 more authors.
Background: Gene flow and adaptive divergence are key aspects of metapopulation dynamics and ecological speciation. Long-distance dispersal is hard to detect and few studies estimate dispersal in combination with adaptive divergence. The aim of this study was to investigate effective long-distance dispersal and adaptive divergence in the fen orchid (Liparis loeselii (L.) Rich.). We used amplified fragment length polymorphism (AFLP)-based assignment tests to quantify effective long-distance dispersal at two different regions in Northwest Europe. In addition, genomic divergence between fen orchid populations occupying two distinguishable habitats, wet dune slacks and alkaline fens, was investigated by a genome scan approach at different spatial scales (continental, landscape and regional) and based on 451 AFLP loci.Results: We expected that different habitats would contribute to strong divergence and restricted gene flow resulting in isolation-by-adaptation. Instead, we found remarkably high levels of effective long-distance seed dispersal and low levels of adaptive divergence. At least 15% of the assigned individuals likely originated from among-population dispersal events with dispersal distances up to 220 km. Six (1.3%) 'outlier' loci, potentially reflecting local adaptation to habitat-type, were identified with high statistical support. Of these, only one (0.22%) was a replicated outlier in multiple independent dune-fen population comparisons and thus possibly reflecting truly parallel divergence. Signals of adaptation in response to habitat type were most evident at the scale of individual populations.Conclusions: The findings of this study suggest that the homogenizing effect of effective long-distance seed dispersal may overwhelm divergent selection associated to habitat type in fen orchids in Northwest Europe. © 2014 Vanden Broeck et al.; licensee BioMed Central Ltd. Source
Leducq J.-B.,CNRS Evolution, Ecology, and Paleonthology Laboratory |
Leducq J.-B.,Laval University |
Siniarsky C.,CNRS Evolution, Ecology, and Paleonthology Laboratory |
Gosset C.C.,CNRS Evolution, Ecology, and Paleonthology Laboratory |
And 9 more authors.
Biscutella neustriaca is an isolated plant taxon with about three thousand known individuals distributed in several fragmented populations. Despite its status as an endangered plant subject to a European LIFE programme for its protection, no conclusive genetic analysis has been performed to help its conservation. We analysed the genetic variability and distribution of nuclear microsatellite markers in a large sample of the population, as well as of the MatK chloroplastic gene in a subsample. We showed, first, that both pollen and seed dispersal, as well as clonal reproduction are strongly limited, and the mating system is obligate outcrossing. Second, we detected two highly divergent chloroplast haplogroups, as well as two completely distinct nuclear gene pools suggesting an ancient isolation between two groups of populations. Intriguingly, a third group of populations appears to combine the nuclear gene pool of one group with the chloroplast haplotype of the other group, suggesting a more recent dramatic colonization and foundation event. Thanks to complementary geological and historical data, we propose a scenario for the evolutionary history of this metapopulation influenced by the dynamics of Seine meanders and human activities. Finally, we give some suggestions for future conservation actions. © 2012 Springer Science+Business Media Dordrecht. Source