Éditeur(s) : HAL CCSD Linnean Society of London
Résumé : Disentangling the impact of landscape features such as rivers and historical events on dispersal is a challenging but necessary task to gain a comprehensive picture of the evolution of diverse biota such as that found in Amazonia. Adenomera andreae, a small, territorial, terrestrial frog species of the Amazonian forest represents a good model for such studies. We combined cytochrome b sequences with 12 microsatellites to investigate the genetic structure at two contrasted spatial scales in French Guiana: along a similar to 6-km transect, to evaluate dispersal ability, and between paired bank populations along a similar to 65-km stretch of the Approuague river, to test the effect of rivers as barriers to dispersal. We observed significant spatial genetic structure between individuals at a remarkably small geographical scale, and conclude that the species has a restricted dispersal ability that is probably tied to its life-history traits. Mitochondrial and microsatellite data also indicate a high level of differentiation among populations on opposite banks of the river, and, in some cases, among populations on the same riverbank. These results suggest that the observed population structure in A. andreae is the result of restricted dispersal abilities combined with the action of rivers and Quaternary population isolation. Given that Amazonia hosts a great portion of anurans, as well as other small vertebrates, that display life-history traits comparable with A. andreae, we argue that our analyses provide new insights into the complex interactions among evolutionary processes shaping Amazonian biodiversity. (c) 2012 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 106, 356373.
ISSN: 0024-4066

hal-01032422
https://hal.archives-ouvertes.fr/hal-01032422
DOI : 10.1111/j.1095-8312.2012.01871.x

Éditeur(s) : HAL CCSD
Résumé : CIRAD, Montpellier, Perspective
In the Brazilian Amazon, degraded forests dominate the landscapes on the agricultural frontiers. This region is now facing a major challenge: halting degradation and sustainably managing these forests. Today, degraded forests represent a class of forest in their own right. They can nevertheless play a key role in combating climate change, and can also help to improve the ecological functioning of the different territories. Implementing public policies with the twin objectives of reducing degradation and promoting these forests implies strong support from research. In this Perspective, we focus on four research priorities: developing methods to characterise and monitor degraded forests; drafting specific forest management plans; understanding the role played by all social actors; and supporting policies at the territorial level.
En Amazonie brésilienne, les forêts dégradées dominent les paysages des fronts pionniers. Un grand défi attend désormais cette région : stopper la dégradation et gérer durablement ces forêts. Les forêts dégradées représentent aujourd’hui une catégorie de forêt à part entière. Elles peuvent néanmoins jouer un rôle majeur pour lutter contre le changement climatique. Elles peuvent aussi contribuer à un meilleur fonctionnement écologique des territoires. Développer des politiques publiques visant le double objectif de réduire la dégradation et de valoriser ces forêts implique un appui fort de la recherche. Dans ce Perspective, nous mettons l’accent sur quatre priorités de recherche : développer des méthodes de caractérisation et de suivi des forêts dégradées, élaborer des plans d’aménagement spécifiques, comprendre le rôle joué par tous les acteurs sociaux et accompagner les politiques à l’échelle territoriale.
Na Amazônia brasileira, as florestas degradadas dominam as paisagens das frentes pioneiras. Atualmente, esta região enfrenta um grande desafio: parar a degradação e fazer a gestão sustentável dessas florestas. As florestas degradadas são atualmente parte integrante de uma categoria de florestas. No entanto, elas podem desempenhar um papel importante na luta contra as mudanças climáticas e podem contribuir para um melhor funcionamento ecológico dos territórios. Desenvolver políticas públicas com o duplo objetivo de reduzir a degradação e melhorar a condição dessas florestas implica um forte apoio da pesquisa. Neste Perspective, nós focalizamos em quatro prioridades de pesquisa: desenvolver os métodos de caracterização e monitoramento das florestas degradadas, elaborar planos específicos de ordenamento do território, compreender o papel desempenhado por todos os atores sociais e acompanhar as politicas em escala territorial.
https://hal.archives-ouvertes.fr/hal-01537653

Droits : http://creativecommons.org/licenses/by-nc-sa/
hal-01537653
https://hal.archives-ouvertes.fr/hal-01537653
https://hal.archives-ouvertes.fr/hal-01537653/document
https://hal.archives-ouvertes.fr/hal-01537653/file/Persp40_LBLanc%20FR.pdf
https://hal.archives-ouvertes.fr/hal-01537653/file/Persp40_LBLanc%20PORT.pdf

Éditeur(s) : HAL CCSD
Résumé : International audience
The Black Curassow (Crax alector) is a large game bird with Vulnerable conservation status found in north-centralSouth America. We examined its distributional pattern across French Guiana using a large number of environmentaldescriptors at 3 scales of analysis: landscape, forest type, and microhabitat. We used a hierarchical model withtemporary emigration and imperfect detection for data collected by standard distance sampling methods at 35study sites. At the landscape scale, Black Curassow density decreased with hunting pressure and increased withsteeper slopes in both hunted and unhunted areas. Topography appeared to be a good proxy for Black Curassowecological requirements and probably reflected habitat quality. At the forest scale, population density wasnegatively correlated with the abundance of palms and Mimosoideae and positively correlated with the abundanceof Lauraceae. Botanical families did not directly influence Black Curassow distribution, but rather determined spatialpatterns by being markers of a particular forest type. At the microhabitat scale, Black Curassows used hilltops morefrequently than other parts of the local topographical gradient. Our multiscale analysis shows that this species’distribution can be explained by biotic or abiotic conditions, regardless of the scale. For conservation, werecommend maintaining connectivity between Black Curassow populations separated by hunted areas. Ourpredicted densities could be used to adapt hunting quotas across French Guiana’s forests. We show that combiningfield and remote sensing data helps to understand the ecological processes responsible for Black Curassow habitatrelationships.
The Condor Ornithological Applications

hal-01455653
https://hal.archives-ouvertes.fr/hal-01455653
https://hal.archives-ouvertes.fr/hal-01455653/document
https://hal.archives-ouvertes.fr/hal-01455653/file/condor-15-28.1.pdf
DOI : 10.1650/CONDOR-15-28.1

Éditeur(s) : HAL CCSD
Résumé : Juin 2003
Dans le contexte actuel de mondialisation, de changement climatique et de forte anthropisation de la biosphère, les Petites Antilles s'érigent en monde marginal ou encore en anti-monde. Fracturées du point de vue politique, économique, linguistique et à certains égards culturel, ces territoires insulaires du Bassin caraïbe recèlent de richesses environnementales (physiques, écosystèmiques et paysagères). Comme partout ailleurs dans le monde humanisé, la survie de ces sociétés implique le rétablissement des grands équilibres écologiques consubstantiels à une articulation efficiente entre le naturel, l'urbain et l'agricole. Compte tenu de la pression démographique, variable d'une île à l'autre, la pérennité des écosystèmes en covariance avec un développement économique profitant au plus grand nombre ne peut se concevoir à l'échelle insulaire. Il semble judicieux d'imaginer un développement à l'échelle de l'archipel basé sur la complémentarité, puisque au sein de chaque composante les diverses ressources biologiques terrestres et marines sont insuffisantes pour assurer une autosuffisance en termes de produits de premières nécessités et d'énergie. Le développement des Petites Antilles s'il doit être durable et prendre comme ossature les directives de Rio (Brésil, 1992) et de Johannesburg (Afrique du Sud, 2002), il devra s'inscrire dans une gestion administrative, scientifique, technique et agricole commune dans le cadre d'une Caraïbe fonctionnellement unifiée. A l'unité floristique, faunistique et biocénotique doivent correspondre des stratégies et donc des politiques, similaires mais diversifiées, d'utilisation des ressources abiotiques (énergie éolienne, hydroélectrique et photovoltaïque) et biotiques (écosystèmes terrestres et marins, flore, faune, sols). Malheureusement dans le présent, la compartimentation économique et politique de la Caraïbe rend ces propos profondément utopiques. Néanmoins dans le futur la survie des peuples des Petites Antilles, impliquera un développement durable signifié par des rapports équilibrés entre hommes et milieux.
–––––
In the nowadays context of "globalization", climatic variation and great anthropization of the biosphere, the Lesser Antilles appear as a marginal world. In a political point of view, those islands offer a greatly distinct and fractured image. The same fact can also be observed in an economic, linguistic and, in a certain measure, cultural perspective. Despite of such a statement, those territories of the Caribbean basin keep economic and landscape resources whom survival depends on the re-establishment of the great ecologic structures implying a productive articulation between the natural, the urban and the agricultural. It seems pertinent to imagine a development on the level of the archipelago based upon complementarity since each constituent presents a limited number of earth and marine biologic reserves which do not guarantee an autosubsistance in energy and first nessecity productivity. A lasting development of the Lesser Antilles supposes a necessary and commun administrative, scientific, technical and agricultural management within the setting of a Caribbean functionally unified. Facing the biocenotic unity, a useful strategy, based on a similar and diversified organization in the exploitation of biophisic resources, must be erected. Such statements could be considered as utopic, regarding the situation of politic and economic division in the Caribbean nowadays. However, in the future, the survival of those insular societies will imply a lasting development lying upon an efficient relationship between Man and environment.
https://halshs.archives-ouvertes.fr/halshs-00003054

Droits : info:eu-repo/semantics/OpenAccess
halshs-00003054
https://halshs.archives-ouvertes.fr/halshs-00003054
https://halshs.archives-ouvertes.fr/halshs-00003054/document
https://halshs.archives-ouvertes.fr/halshs-00003054/file/Devpt-durable_JOSEPH-PHILIPPE.pdf

Éditeur(s) : HAL CCSD Wiley
Résumé : The evolutionary potential of long-lived species, such as forest trees, is fundamental for their local persistence under climate change (CC). Genome–environment association (GEA) analyses reveal if species in heterogeneous environments at the regional scale are under differential selection resulting in populations with potential preadaptation to CC within this area. In 79 natural [i]Fagus sylvatica[/i] populations, neutral genetic patterns were characterized using 12 simple sequence repeat (SSR) markers, and genomic variation (144 single nucleotide polymorphisms (SNPs) out of 52 candidate genes) was related to 87 environmental predictors in the latent factor mixed model, logistic regressions and isolation by distance/environmental (IBD/IBE) tests. SSR diversity revealed relatedness at up to 150m intertree distance but an absence of large-scale spatial genetic structure and IBE. In the GEA analyses, 16 SNPs in 10 genes responded to one or several environmental predictors and IBE, corrected for IBD, was confirmed. The GEA often reflected the proposed gene functions, including indications for adaptation to water availability and temperature. Genomic divergence and the lack of large-scale neutral genetic patterns suggest that gene flow allows the spread of advantageous alleles in adaptive genes. Thereby, adaptation processes are likely to take place in species occurring in heterogeneous environments, which might reduce their regional extinction risk under CC
ISSN: 0028-646X

hal-01309135
https://hal.archives-ouvertes.fr/hal-01309135
PRODINRA : 343710
DOI : 10.1111/nph.13809

Éditeur(s) : HAL CCSD IOS Press
Résumé : International audience
Cancer is generally conceived as a dedifferentiation process in which quiescent post-mitotic differentiated cells acquire stem-like properties and the capacity to proliferate. This view holds for the initial stages of carcinogenesis but is more questionable for advanced stages when the cells can transdifferentiate into the contractile phenotype associated to migration and metastasis. Singularly from this perspective, the hallmark of the most aggressive cancers would correspond to a genuine differentiation status, even if it is different from the original one. This seeming paradox could help reconciling discrepancies in the literature about the pro-or anti-tumoral functions of candidate molecules involved in cancer and whose actual effects depend on the tumoral grade. These ambiguities which are likely to concern a myriad of molecules and pathways, are illustrated here with the selected examples of chromatin epigenetics and myocardin-related transcription factors, using the human MCF10A and MCF7 breast cancer cells. Self-renewing stem like cells are characterized by a loose chromatin with low levels of the H3K9 trimetylation, but high levels of this mark can also appear in cancer cells acquiring a contractile-type differentiation state associated to metastasis. Similarly, the myocardin-related transcription factor MRTF-A is involved in metastasis and epithelial-mesenchymal transition, whereas this factor is naturally enriched in the quiescent cells which are precisely the most resistant to cancer: cardiomyocytes. These seeming paradoxes reflect the bistable epigenetic landscape of cancer in which dedifferentiated self-renewing and differentiated migrating states are incompatible at the single cell level, though coexisting at the population level. © 2016-IOS Press and the authors. All rights reserved.
ISSN: 0888-6008

hal-01367146
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01367146
DOI : 10.3233/BD-150210
PUBMED : 27177343

Éditeur(s) : HAL CCSD
Résumé : International audience
Here, we synthesize conceptual frameworks, applied modeling approaches, and as case studies to highlight complex social-ecological system (SES) dynamics that inform environmental policy, conservation and management. Although a set of “good practices” about what constitutes a good SES study are emerging, there is still a disconnection between generating SES scientific studies and providing decision-relevant information to policy makers. Classical single variable/hypothesis studies rooted in one or two disciplines are still most common, leading to incremental growth in knowledge about the natural or social system, but rarely both. The recognition of human dimensions is a key aspect of successful planning and implementation in natural resource management, ecosystem-based management, fisheries management, and marine conservation. The lack of social data relating to human-nature interactions in this particular context is now seen as an omission, which can often erode the efficacy of any resource management or conservation action. There have been repeated calls for a transdisciplinary approach to complex SESs that incorporates resilience, complexity science characterized by intricate feedback interactions, emergent processes, non-linear dynamics and uncertainty. To achieve this vision, we need to embrace diverse research methodologies that incorporate ecology, sociology, anthropology, political science, economics and other disciplines that are anchored in empirical data. We conclude that to make SES research most useful in adding practical value to conservation planning, marine resource management planning processes and implementation, and the integration of resilience thinking into adaptation strategies, more research is needed on (1) understanding social-ecological landscapes and seascapes and patterns that would ensure planning process legitimacy, (2) costs of transformation (financial, social, environmental) to a stable resilient social-ecological system, (3) overcoming place-based data collection challenges as well as modeling challenges.
Ocean and Coastal Management

Droits : http://creativecommons.org/licenses/by-nc-nd/
hal-01224152
https://hal-univ-perp.archives-ouvertes.fr/hal-01224152
https://hal-univ-perp.archives-ouvertes.fr/hal-01224152/document
https://hal-univ-perp.archives-ouvertes.fr/hal-01224152/file/1-s2.0-S096456911500126X-main.pdf
DOI : 10.1016/j.ocecoaman.2015.04.018

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
The increased use of pesticides has caused concern over the possible direct association of exposure to combinations of these compounds with bee health problems. There is growing proof that bees are regularly exposed to mixtures of agrochemicals, but most research has been focused on managed bees living in farmland, whereas little is known about exposure of wild bees, both in farmland and urban habitats. To determine exposure of wild bumblebees to pesticides in agricultural and urban environments through the season, specimens of five different species were collected from farms and ornamental urban gardens in three sampling periods. Five neonicotinoid insecticides, thirteen fungicides and a pesticide synergist were analysed in each of the specimens collected. In total, 61% of the 150 individuals tested had detectable levels of at least one of the compounds, with boscalid being the most frequently detected (35%), followed by tebuconazole (27%), spiroxamine (19%), carbendazim (11%), epoxiconazole (8%), imidacloprid (7%), metconazole (7%) and thiamethoxam (6%). Quantifiable concentrations ranged from 0.17 to 54.4 ng/g (bee body weight) for individual pesticides. From all the bees where pesticides were detected, the majority (71%) had more than one compound, with a maximum of seven pesticides detected in one specimen. Concentrations and detection frequencies were higher in bees collected from farmland compared to urban sites, and pesticide concentrations decreased through the season. Overall, our results show that wild bumblebees are exposed to multiple pesticides when foraging in agricultural and urban landscapes. Such mixtures are detected in bee tissues not just during the crop flowering period, but also later in the season. Therefore, contact with these combinations of active compounds might be more prolonged in time and widespread in the environment than previously assumed. These findings may help to direct future research and pesticide regulation strategies to promote the conservation of wild bee populations.
ISSN: 0269-7491

hal-01477203
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01477203
https://hal-univ-rennes1.archives-ouvertes.fr/hal-01477203/file/Quantifying%20exposure%20of%20wild%20bumblebees_accepted.pdf
DOI : 10.1016/j.envpol.2017.01.001
PUBMED : 28087090

Éditeur(s) : HAL CCSD American Association for the Advancement of Science
Résumé : International audience
Most eukaryotic organisms are arthropods. Yet, their diversity in rich terrestrial ecosystems is still unknown. Here we produce tangible estimates of the total species richness of arthropods in a tropical rainforest. Using a comprehensive range of structured protocols, we sampled the phylogenetic breadth of arthropod taxa from the soil to the forest canopy in the San Lorenzo forest, Panama. We collected 6144 arthropod species from 0.48 hectare and extrapolated total species richness to larger areas on the basis of competing models. The whole 6000-hectare forest reserve most likely sustains 25,000 arthropod species. Notably, just 1 hectare of rainforest yields >60% of the arthropod biodiversity held in the wider landscape. Models based on plant diversity fitted the accumulated species richness of both herbivore and nonherbivore taxa exceptionally well. This lends credence to global estimates of arthropod biodiversity developed from plant models.
ISSN: 0036-8075

hal-00817285
https://hal.archives-ouvertes.fr/hal-00817285
https://hal.archives-ouvertes.fr/hal-00817285/document
https://hal.archives-ouvertes.fr/hal-00817285/file/1226727Revisedtext.pdf
DOI : 10.1126/science.1226727

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : Region Gdansk Pomerania is an excellent geographic area for the development of yachting. Gdansk Bay and the Vistula Lagoon is characterized by very good weather conditions. Numerous advantages of anthropogenic and tourist resorts strengthen the attractiveness of the coast. The marina recently ended in Gdansk, Sopot and Gdynia create very good conditions for the development of yachting. The combination of the Gulf of Gdansk by the river network and channels Żuławy of the Great Masurian Lakes promotes the development of yachting in both the Gulf of Gdansk and Masurian Lake region. However, new infrastructure investments, realized with funding from the EU, like ‘Loop Żuławska’ and the new marina, leading to an increase in tourist traffic and threats to existing reserves and landscape parks. Another problem is the lack of regulation of the right on the crossing of the Strait of Baltiysk, leading from the Vistula Lagoon on the Baltic Sea, which is located in the territorial waters of Russia. The concentration of investments in the region of Żuławy contrasts with too little spending on development of tourist infrastructure in the Hel Peninsula. There are large disparities in tourist traffic. Tourism in Hel Peninsula significantly exceeded the absorption of tourism in the region and leads to the degradation of the local environment. In addition, the seasonality of tourism on the coast favours the trend of maximizing profit tourism enterprises. New, designed ditch the Vistula Spit, which connects directly to the Vistula Lagoon from the Baltic Sea, bypassing the Russian territorial waters, can lead to serious ecological changes.
La région de Gdansk en Poméranie est une excellente zone géographique pour le développement du yachting. La baie de Gdansk et la lagune de la Vistule se caractérisent par de très bonnes conditions climatiques. Divers avantages anthropiques et stations touristiques renforcent l’attractivité de la côte.Les marinas nouvellement terminées à Gdansk, Sopot et Gdynia, créent de très bonnes conditions pour le développement du yachting. La combinaison du golfe de Gdansk, du réseau fluvial et des canaux Żuławy qui relient les Grands Lacs de Mazuries, favorise le développement du yachting dans le golfe de Gdansk et la région des lacs. Les nouveaux investissements dans les infrastructures, réalisés grâce à des financements de l’Union européenne, tels "Loop Żuławska" et la nouvelle marina, conduisent à une augmentation de l’activité touristique qui menace les réserves existantes et les parcs naturels. L’autre problème est l’absence de réglementation relative au droit de passage dans le détroit de Baltiysk, menant de la lagune de la Vistule, qui est située dans les eaux territoriales de la Russie. Entre la concentration des investissements dans la région de Żuławy et les faibles dépenses pour le développement de l’infrastructure touristique dans la péninsule d’Hel, il existe de grandes disparités dans le trafic touristique. Les infrastructures touristiques de la péninsule d’Hel ne sont pas en mesure d’absorber les flux touristiques de la région et la situation conduit inéluctablement à la dégradation de l’environnement. La situation de la lagune de la Vistule, dont les eaux sont partagées entre la Russie et la Pologne, peut entraîner de graves changements écologiques.
Gdańsk
Pologne
Poméranie
Hel
Zulawy

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.10762
http://journals.openedition.org/etudescaribeennes/10762

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : Precise mapping of above-ground biomass (AGB) is a major challenge for the success of REDD+ processes in tropical rainforest. The usual mapping methods are based on two hypotheses: a large and long-ranged spatial autocorrelation and a strong environment influence at the regional scale. However, there are no studies of the spatial structure of AGB at the landscapes scale to support these assumptions. We studied spatial variation in AGB at various scales using two large forest inventories conducted in French Guiana. The dataset comprised 2507 plots (0.4 to 0.5 ha) of undisturbed rainforest distributed over the whole region. After checking the uncertainties of estimates obtained from these data, we used half of the dataset to develop explicit predictive models including spatial and environmental effects and tested the accuracy of the resulting maps according to their resolution using the rest of the data. Forest inventories provided accurate AGB estimates at the plot scale, for a mean of 325 Mg.ha^-1. They revealed high local variability combined with a weak autocorrelation up to distances of no more than10 km. Environmental variables accounted for a minor part of spatial variation. Accuracy of the best model including spatial effects was 90 Mg.ha^-1 at plot scale but coarse graining up to 2-km resolution allowed mapping AGB with accuracy lower than 50 Mg.ha^-1. Whatever the resolution, no agreement was found with available pan-tropical reference maps at all resolutions. We concluded that the combined weak autocorrelation and weak environmental effect limit AGB maps accuracy in rainforest, and that a trade-off has to be found between spatial resolution and effective accuracy until adequate “wall-to-wall” remote sensing signals provide reliable AGB predictions. Waiting for this, using large forest inventories with low sampling rate (<0.5%) may be an efficient way to increase the global coverage of AGB maps with acceptable accuracy at kilometric resolution
ISSN: 1932-6203

hal-01269305
https://hal.archives-ouvertes.fr/hal-01269305
DOI : 10.1371/journal.pone.0138456
PRODINRA : 326359

Éditeur(s) : HAL CCSD Elsevier
Résumé : International audience
This study constitutes one of the few works conducted on the colonization of recent lava flows by fish communities in coral reef environment. It attempted to describe the mechanisms of colonization and environmental variables infuencing the structure of communities on the lava flows of the Piton de la Fournaise volcano at Reunion Island. It also proposed some hypotheses on the mechanisms of selection and speciation of endemic species of thesouthwestern Indian Ocean region, particularly diversified on the most recent lava flows of the Piton de la Fournaise, and provided a model of distribution of environmental and fish assemblage variables in four homogeneous patterns of colonization (landscapes) retained within the study area. The results showed fish community structure strongly related to measured environmental variables, of which depth, width of the island shelf, age of the lava flow and distance to the most recent lava flow were the most influential. It also appeared that the maximum endemic species richness was measured on the shallower stations, with narrow insular shelf, located on recent lava flows, near the lava flow from the eruption of 2007 (latest volcanic event). These characteristics define a harsh environment, to which endemic species seem well-adapted due in particular to their strong demographic and dietary flexibility. Finally, the patterns of colonization were characterized by significantly different environmental variables. The four homogeneous areas, defined by two geomorphological features, basalt blocks and drop-offs, nested within two locations, inside and outside the volcanic enclosure (current caldera), hosted fish communities whose dominant diets mainly depend on the nature, the abundance and the accessibility of available food resources. Overall, the study highlights that during early stages of ecological succession, site selection by fish communities is highly dependent on environmental constraints, specially of volcanic origin, but the physical habitat selection (geomorphology, substrate rugosity, percentage of soft substrate) seems to have littleimportance, while at least on the trophic structure and the distribution of endemic species.
ISSN: 0022-0981

hal-01253768
https://hal.archives-ouvertes.fr/hal-01253768
https://hal.archives-ouvertes.fr/hal-01253768/document
https://hal.archives-ouvertes.fr/hal-01253768/file/Pinault%20et%20al.%20-%202014%20-%20Fish%20community%20structure%20in%20relation%20to%20environmen_hal.pdf
DOI : 10.1016/j.jembe.2014.06.005

Éditeur(s) : HAL CCSD Public Library of Science
Résumé : The analysis of fine-scale spatial genetic structure (FSGS) within populations can provide insights into eco-evolutionary processes. Restricted dispersal and locally occurring genetic drift are the primary causes for FSGS at equilibrium, as described in the isolation by distance (IBD) model. Beyond IBD expectations, spatial, environmental or historical factors can affect FSGS. We examined FSGS in seven African and Neotropical populations of the late-successional rain forest tree Symphonia globulifera L. f. (Clusiaceae) to discriminate the influence of drift-dispersal vs. landscape/ecological features and historical processes on FSGS. We used spatial principal component analysis and Bayesian clustering to assess spatial genetic heterogeneity at SSRs and examined its association with plastid DNA and habitat features. African populations (from Cameroon and São Tomé) displayed a stronger FSGS than Neotropical populations at both marker types (mean Sp = 0.025 vs. Sp = 0.008 at SSRs) and had a stronger spatial genetic heterogeneity. All three African populations occurred in pronounced altitudinal gradients, possibly restricting animal-mediated seed dispersal. Cyto-nuclear disequilibria in Cameroonian populations also suggested a legacy of biogeographic history to explain these genetic patterns. Conversely, Neotropical populations exhibited a weaker FSGS, which may reflect more efficient wide-ranging seed dispersal by Neotropical bats and other dispersers. The population from French Guiana displayed an association of plastid haplotypes with two morphotypes characterized by differential habitat preferences. Our results highlight the importance of the microenvironment for eco-evolutionary processes within persistent tropical tree populations.
ISSN: 1932-6203

hal-01608324
https://hal.archives-ouvertes.fr/hal-01608324
DOI : 10.1371/journal.pone.0182515
PRODINRA : 403154
PUBMED : 28771629

Éditeur(s) : Université des Antilles Études caribéennes
Résumé : La mer des Caraïbes abrite une diversité de biotopes littoraux qui favorisent l’installation de trois écosystèmes - les récifs coralliens, les mangroves et les herbiers – riches et complexes. On y trouve également d’autres formations uniques tels les stromatolithes ou les trous bleus. Des conditions climatiques et océanographiques homogènes permettent à l’ensemble du bassin Caraïbe de constituer une unité sur les plans floristique et faunistique. Cette unité n’exclut pas une diversité biologique exceptionnelle avec notamment des espèces endémiques à la zone ; ce qui confère aux côtes des pays caribéens un intérêt écologique, paysager et scientifique certain. La reconnaissance sur le plan international et régional de l’importance de la Mer des Caraïbes mais aussi de sa fragilité a permis au milieu marin caribéen d’acquérir son statut de patrimoine naturel.En plus des services écosystémiques qu’elle rend (ressources halieutiques, protection des littoraux…), la Mer des Caraïbes constitue un atout indéniable dans le cadre du développement touristique de la zone aussi bien par le balnéaire que, plus récemment, par l’écotourisme. Ce dernier s’appuie généralement sur des aires marines protégées et doit permettre un développement durable des îles.A partir d’une étude de cas, le parc marin de Saba, l’objectif de cette étude est d’analyser les rapports entre patrimoine naturel marin et l’écotourisme, ainsi que les impacts économiques, sociaux et environnementaux de la mise en valeur de ces ressources.
The Caribbean Sea is home to a diversity of coastal habitats that support the installation of three rich and complex ecosystems - coral reefs, mangroves and seagrasses -. There are also other unique formations such as stromatolites or blue holes. Oceanographic and climatic conditions allow homogeneous throughout the Caribbean basin to form a unit in terms of flora and fauna. This unit does not exclude an exceptional biological diversity, including species endemic to the area, which give the coasts of the Caribbean countries an ecological, landscape and some science. Recognition on the international and regional importance of the Caribbean Sea but also its fragile marine environment has allowed the Caribbean to gain its status as a natural heritage.In addition to the ecosystem services it render (fisheries, coastal protection ...), the Caribbean Sea is a definite asset in the development of tourism in the area by the seaside as well as, more recently, ecotourism. The latter is generally based on marine protected areas and should facilitate the sustainable development of islands.From a case study, the Saba Marine Park, the objective of this study is to analyze the relationship between natural heritage and marine ecotourism, as well as economic, social and environmental development of these resources.
Saba

Droits : info:eu-repo/semantics/openAccess
urn:doi:10.4000/etudescaribeennes.5487
http://journals.openedition.org/etudescaribeennes/5487

Éditeur(s) : HAL CCSD Wiley-Blackwell Wiley
Résumé : A new record from the heart of the Moroccan Middle Atlas cedar forests spans the last 18 000 years and provides valuable insight into our understanding of the natural vegetation and environmental changes. The approach is based on the study of pollen content, geochemical elements and grain size analysis. The pollen data indicate that the vegetation was dominated by herbaceous plants until 9000 BP. Such open landscape allowed greater soil erosion and an input of chemical elements from the watershed. After 9000 BP, tree cover, mainly oak, increased slightly and was accompanied by a higher taxonomic diversity. However, several steppe elements remain well represented in the area until 5000 BP, which suggests that the climate was rather dry during the first part of the Holocene. After 6000 BP, the climate became more favourable to expansion of the forest ecosystems, including Cedrus atlantica, thereby reducing erosion. A strong reduction of the tree pollen percentages is recorded after 2000 BP, which may be related to increasing human activities during the Roman period. These forest changes are concomitant with an increase of lead and copper concentrations in the record, probably related to Roman metalworking activities.
ISSN: 0267-8179

hal-01122848
https://hal.archives-ouvertes.fr/hal-01122848
DOI : 10.1002/jqs.2708