Introduced deer and the pollination and reproduction of an animal-pollinated herb

We evaluated the hypothesis that the modified population density of Aquilegia formosa Fisch. ex DC. (Ranun culaceae) resulting from the introduction of Sitka black-tailed deer (Odocoileus hemionus sitkensis) in the Haida Gwaii ar chipelago affects the pollination and reproductive performance of this herbaceous species. We compared the population density, pollination, and reproductive success of A. formosa among three small islands colonized by deer and three deer-free islands. Islands with deer had a substantially lower absolute density and a greater relative density of A. formosa than deer-free islands. The presence of deer was associated with higher pollen deposition, which probably resulted from the greater relative density of A. formosa on islands with deer. However, the presence of deer had no significant effect on in dividual reproductive success. The latter result is likely a consequence of the lack of pollen limitation in this species, as well as of the conflicting relationship between the absolute and relative densities of A. formosa and the presence of deer.Fil: Vazquez, Diego P.. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Provincia de Mendoza. Instituto Argentino de Investigaciones de las Zonas Áridas. Universidad Nacional de Cuyo. Instituto Argentino de Investigaciones de las Zonas Áridas; ArgentinaFil: Gresser, Julie. École nationale supérieure d’agronomie de Montpellier; FranciaFil: Martin, Jean-Louis. Carleton University; Canad

Processus érosifs et transport solide en milieu tropical insulaire. Cas des bassins versants de la Baie du Robert, Martinique, FWI

Particulièrement vulnérable aux pressions d’origine anthropique, la Baie du Robert en Martinique est marquée par une dégradation généralisée de ses écosystèmes. L’envasement des fonds marins, les changements de bathymétrie et la dégradation de biocénoses remarquables sont notamment les conséquences d’un apport excessif de particules solides dans la baie. Sur certains sous-bassins versants de ce territoire, nous avons caractérisé et quantifié le transfert de solutés dans les eaux superficielles. Une première approche qualitative a permis d’établir un diagnostic cartographié de la vulnérabilité des terres à l’érosion à l’échelle des bassins versants. Dans un deuxième temps, un réseau de stations de mesures a été installé pour évaluer quantitativement le régime hydrologique et la dynamique de transport solide des cours d’eau instrumentés. Les principaux résultats de cette seconde étape permettent de caractériser les variations spatiales et temporelles du transport solide et d’estimer les quantités de matériaux entraînés en fonction des spécificités des sous-bassins instrumentés.In Martinique (FWI), the Robert bay is characterised by some signs of eutrophication and hyper sedimentation, inducing impacts on its natural ecosystems. This study has allowed highlighting some of the main driving factors of erosion processes in the catchment basins. Combination of agricultural practices and human settlements uphill during the last decades is one of the phenomena of erosion amplification. A first step was to build a diagnosis of erosion vulnerability in the catchment basins. The second step was dedicated to design monitoring programmes, install equipment and collect physical and chemical data on three different basins. First results allow improving scientific knowledge on spatiotemporal variability of solid transport on catchment basin scale and assessing contribution of solid transport in pesticides contamination

A conceptual model of organochlorine fate from a combined analysis of spatial and mid-to long-term trends of surface and ground water contamination in tropical areas (FWI)

International audienceIn this study, we investigated the management of long-term environmental pollution by organic pollutants such as organochlorine pesticides. We set out to identify conditions that are conducive to reducing pollution levels for these persistent molecules and then propose a conceptual model of organochlorine fate in water. Our approach looked at spatio-temporal changes in pollutant contents in surface water (SW) and groundwater (GW) on a large scale, in order to decipher the respective roles of soil, geology, hydrology and past treatment practices. The case of chlordecone (CLD) on the island of Martinique (1100 km(2)) was selected given the sampling campaigns carried out since 2007 over more than 150 sites. CLD, its metabolite chlordecone-5b-hydro(5bCLD) and the metabolite-to-parent-compound ratio were compared. As regards the spatial variability of water contamination, our results showed that banana cropping areas explained the location of contaminated SW and GW, whereas the combination of soil and geology factors explained the main spatial variability in the 5bCLD/CLD ratio. For temporal variability, these conditions defined a high diversity of situations in terms of the duration of pollution, highlighting two groups: water draining old geological formations and ferralsols or vertisols vs. recent geology and andosols. A conceptual leaching model provided some key information to help interpret downward trends in CLD and 5bCLD observed in water. Lastly, a conceptual model of organochlorine fate is proposed to explain the diversity of the 5bCLD/CLD ratio in water. Our conclusions highlight the combined role of soil and groundwater residence time for differentiating between conditions that are more conducive, or not, to the disappearance of CLD from the environment. This paper presents a model that provides an overall perception of organochlorine pesticide fate in the environment

Identification of marine key areas across the Caribbean to ensure the conservation of the critically endangered hawksbill turtle

International audienceAcquisition of data on animal movement when developing management strategies is a common challenge in species conservation, especially when dealing with a critically endangered species as the hawksbill turtle Eretmochelys imbricata. To reach the objective of the 2008 national action plan for Martinique Island (French West Indies), the present paper examines horizontal and vertical movements in juveniles (n = 3) and adults life stages (11 females and 2 males) of 16 hawksbill turtles. Our results reveal the strong site fidelity of individuals to their foraging grounds (mean male foraging home range: 89.3 ± 20.2 km 2 , mean female foraging home range: 336 ± 284.7 km 2 , mean juvenile foraging home range: 157.3 ± 71.2 km 2) and to the females' inter-nesting areas (mean home range: 284.2 ± 523.7 km 2). A spatial foraging overlap occurred between juveniles and males as they shared 41% of their 95% kernel foraging habitat. The turtles performed mainly long and shallow dives within the first 20 m deep around Martinique Island, occupying shallow waters close to shore. The migratory routes of the adult females revealed regional connectivity between the Caribbean islands, crossing 31 exclusive economic zones and international waters, and featuring distinct foraging grounds. This finding reinforces the significance of a cooperative network at the Caribbean scale to ensure the efficient conservation of this critically endangered species

Behavioural inference from signal processing using animal-borne multi-sensor loggers: a novel solution to extend the knowledge of sea turtle ecology

International audienceThe identification of sea turtle behaviours is a prerequisite to predicting the activities and time-budget of these animals in their natural habitat over the long term. However, this is hampered by a lack of reliable methods that enable the detection and monitoring of certain key behaviours such as feeding. This study proposes a combined approach that automatically identifies the different behaviours of free-ranging sea turtles through the use of animal-borne multi-sensor recorders (accelerometer, gyroscope and time-depth recorder), validated by animal-borne videorecorder data. We show here that the combination of supervised learning algorithms and multisignal analysis tools can provide accurate inferences of the behaviours expressed, including feeding and scratching behaviours that are of crucial ecological interest for sea turtles. Our procedure uses multi-sensor miniaturized loggers that can be deployed on free-ranging animals with minimal disturbance. It provides an easily adaptable and replicable approach for the long-term automatic identification of the different activities and determination of time-budgets in sea turtles. This approach should also be applicable to a broad range of other species and could significantly contribute to the conservation of endangered species by providing detailed knowledge of key animal activities such as feeding, travelling and resting

Connecting paths between juvenile and adult habitats in the Atlantic green turtle using genetics and satellite tracking

International audienceAlthough it is commonly assumed that female sea turtles always return to the beach they hatched, the pathways they use during the years preceding their first reproduction and their natal origins are most often unknown, as it is the case for juvenile green turtles found in Martinique waters in the Caribbean. Given the oceanic circulation of the Guiana current flowing toward Martinique and the presence of important nesting sites for this species in Suriname and French Guiana, we may assume that a large proportion of the juvenile green turtles found in Martinique are originating from the Suriname-French Guiana beaches. To confirm this hypothesis, we performed mixed stock analysis (MSA) on 40 green turtles sampled in Martinique Island and satellite tracked 31 juvenile green turtles tagged in Martinique to (a) assess their natal origin and (b) identify their destination. Our results from MSA confirm that these juveniles are descendant from females laying on several Caribbean and Atlantic beaches, mostly from Suriname and French Guiana, but also from more southern Brazilian beaches. These results were confirmed by the tracking data as the 10 turtles leaving Martinique headed across the Caribbean-Atlantic region in six different directions and 50% of these turtles reached the Brazilian foraging grounds used by the adult green turtles coming from French Guiana. One turtle left the French Guianan coast to perform the first transatlantic migration ever recorded in juvenile green turtles, swimming toward Guinea-Bissau, which is the most important nesting site for green turtles along the African coast. The extensive movements of the migrant turtles evidenced the crossing of international waters and more than 25 exclusive economic zones, reinforcing the need for an international cooperative network to ensure the conservation of future breeders in this endangered species

High fidelity of sea turtles to their foraging grounds revealed by satellite tracking and capture-mark-recapture: New insights for the establishment of key marine conservation areas

Movement ecology studies are essential to protect highly mobile threatened species such as the green turtle (Chelonia mydas), classified as an endangered species by the IUCN. In 2019, the South Atlantic subpopulation has been downlisted to ‘Least Concern’, but the maintenance of this status strongly relies on the pursuit of research and conservation, especially on immatures, which contribute to the demographic renewal of this subpopulation. Identifying marine areas used by immatures is therefore crucial to implement efficient measures for the conservation of sea turtles in the Caribbean. We analysed data of capture-mark-recapture of 107 (out of 299) immatures recaptured at least once in Martinique, and satellite tracked 24 immatures to investigate their site fidelity and habitat use. Our results revealed a strong fidelity to foraging grounds, with mean residence times higher than 2 years, and with a high degree of affinity for specific areas within the coastal marine vegetation strip. Home ranges (95% kernel contour) and core areas (50% kernel contour) varied from 0.17 to 235.13 km2 (mean ± SD = 30.73 ± 54.34 km2) and from 0.03 to 22.66 km2 (mean ± SD = 2.95 ± 5.06 km2), respectively. Our findings shed light on a critical developmental area for immature green turtles in the French West Indies, and should help to refine Regional Management Units and reinforce the cooperative network aiming at ensuring conservation of the species at international scale