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International audience; In this chapter, we propose a new kind of participatory device designed as a serious game suitable for geoprospective workshops and dedicated to help the setting of multiscale and multisectoral long-term adaptation plans to global change. We explain how and why we combined the concepts of the Coupled Infrastructure System with the paradigm of Multi-Agents System to build a generic conceptual model. We present the two games designed with this framework at this date and describe them precisely from their conceptual models up to examples of results obtained during the participatory sessions organized on the field with real stakeholders. The first example is about the George municipality in South Africa and sessions were organized in coordination with South African National park institution (SAN parks). The second example is about the territory of the Scheme Of Territorial Consistency (SCOT) “South of Gard” department in France and sessions were organized with the SCOT “South of Gard” and other institutions.

International audience; Bats are the second most species-rich Mammalian order and provide a wide range of ecologically important and economically significant ecosystem services. Nipah virus is a zoonotic emerging infectious disease for which pteropodid bats have been identified as a natural reservoir. In Cambodia, Nipah virus circulation has been reported in Pteropus lylei, but little is known about the spatial distribution of the species and the associated implications for conservation and public health. We deployed Global Positioning System (GPS) collars on 14 P. lylei to study their movements and foraging behavior in Cambodia in 2016. All of the flying foxes were captured from the same roost, and GPS locations were collected for 1 month. The habitats used by each bat were characterized through ground-truthing, and a spatial distribution model was developed of foraging sites. A total of 13,643 valid locations were collected during the study. Our study bats flew approximately 20 km from the roost each night to forage. The maximum distance traveled per night ranged from 6.88-105 km and averaged 28.3 km. Six of the 14 bats visited another roost for at least one night during the study, including one roost located 105 km away. Most foraging locations were in residential areas (53.7%) followed by plantations (26.6%). Our spatial distribution model confirmed that residential areas were the preferred foraging habitat for P. lylei, although our results should be interpreted with caution due to the limited number of individuals studied. Synthesis and applications: Our findings suggest that the use of residential and agricultural habitats by P. lylei may create opportunities for bats to interact with humans and livestock. They also suggest the importance of anthropogenic habitats for conservation of this vulnerable and ecologically important group in Cambodia. Our mapping of the probability of occurrence of foraging sites will help identification of areas where public awareness should be promoted regarding the ecosystem services provided by flying foxes and potential for disease transmission through indirect contact.

National audience

Although global positioning system (GPS) location data have been used to derive animal movement parameters including step length, rarely have these parameters been used to predict animal responses to human interventions. In this study, we tested whether GPS-derived step length of semi-free range cattle is a function of herder presence. The derived step-length model was used to predict herder presence on independent cattle GPS collar data. We also tested whether cattle foraging behaviour is explained by herder activity and vegetation greenness. We used logistic regression to model herder presence as a function of step length and relate cattle behaviour with herder activity and vegetation greenness. The field-based step length model successfully predicted herder presence on GPS collar data. The average predicted frequency of herder presence for the GPS-collared herds was 31%, whilst the field-based GPS frequency was 27%. Herding activities and vegetation greenness also explained different cattle foraging behaviour.

Poster; International audience

Poster; International audience

In southern Africa, TransFrontier Conservation Areas (TFCAs) are promoting the sustainable coexistence between Mankind and Nature, and are seeking to find a balance between wildlife conservation, agricultural production and natural resource use. In these TFCAs, the various land use types include wildlife/domestic interfaces prone to create human/wildlife conflicts. Amongst those conflicts, disease transmission between buffalo and cattle (and potentially to human for zoonoses) is a serious concern. In this study, we GPS-tracked buffalo and cattle herds in the Great Limpopo TFCA in order to understand disease transmission and estimate the risk of emerging pathogen spillover. This protocol makes it possible to investigate inter-species contacts along multiple spatiotemporal windows, and thus risks of transmission of various pathogens. Regarding buffalo specifically, Adult females were shown to range within stable home ranges, displaying little overlap with adjacent buffalo herds. However, interindividual association patterns strongly challenged the standard concept of herd. Interestingly, two of the young GPS-tracked females displayed long-range (70- 90kms) movements in a few week times, linking distant buffalo populations across communal lands. This shed light on a poorly described behaviour that has major implications in disease ecology in the GLTFCA. We conclude by discussing the implication of buffalo/cattle interactions for disease transmission, particularly in the context of transboundary disease transmission and by listing some hypotheses that will require testing in the near future to manage the health issue at buffalo/cattle interfaces in Africa.

Between 1990 and 1994, geodetic measurements (GPS observations) have been conducted across the New Hebrides subduction zone where the Australia plate subducts under the New Hebrides Arc. This paper establishes convergence rate variations along the trench. In the South, at Tanna, the relative motion is oriented N244 ±4 and has a uniform rate of 11.7±0.8 cm/yr. The rate at Efate is 10.3±0.9 cm/yr, oriented N242 ±4. Both azimuths very well compare with slip vectors of the last major earthquakes. In the North, the rate at Santo is only 3.6 ±1.2 cm/yr, oriented N253 ± 26. The difference in the convergence rates between Santo on the one hand and Efate and Tanna in the other hand points to a right lateral shear zone between Santo and Efate. At Santo where the plate coupling is very high, the very low convergence rate might be related to the absence of recent strong earthquakes. No significant variations are detected for the baselines within the Australia plate.

International audience; We investigated space-use patterns of the West African savanna buffalo (Syncerus caffer brachyceros), a little-studied subspecies occurring at the northern limit of the African buffalo's geographical range. This buffalo generally ranges in small herds (about 45 individuals) and has a low body mass (approximately 400 kg) relative to the Cape buffalo (S. c. caffer). We monitored the movements of 7 breeding herds in W Regional Park (Burkina Faso, Benin, Niger) using global positioning system collars and activity data loggers. Habitat selection was analyzed at both large (interseasonal) and small (intraseasonal) scales in a context where resources are segregated spatially at some times of year. Both biotic (primary production and vegetation types) and abiotic (timing of rainfall and surface water) covariates, and the extent to which neighboring herds shared space, were considered. In the dry season buffalo herds ranged close (within 5.3 +/- 2.0 km, mean +/- SD) to segments of permanent rivers. At the onset of the monsoon all herds but 1 (which had year-round access to suitable resources) performed a large (35 +/- 10 km) directional movement in response to a large-scale gradient of primary production. Spatiotemporal dynamics of forage and water resources thus jointly stimulated interseasonal directional movements and shaped large (335 +/- 167 km(2)) annual home ranges. Furthermore, the establishment of home ranges in the wet season appears to be conditioned by a threshold (about 10%) in the availability of perennial grasses. Habitat-selection analysis at intraseasonal scale also underlines the key role played by perennial grasses for buffaloes. The spatial arrangements of home ranges of neighboring herds also suggest that interherd behavioral avoidance is a high-level constraint on foraging processes. The ability of the African buffalo to cope with contrasting environmental conditions throughout most sub-Saharan ecosystems highlights the high behavioral plasticity of this species.

We estimated home range (HR) and core areas of cattle herds in a semi-arid rangeland in southern Africa using the fixed kernel and the local convex hull (LoCoH) methods. We also compared the HR values of the two methods with the aid of high spatial resolution IKONOS imagery. We also compared area estimates determined by the two methods at different probability contours of the utilization distribution (UD). Results showed that the LoCoH performed better than the kernel method in estimating UD. We found significant (p < 0.05) differences concerning the area estimated at each probability contour of the UD between the fixed kernel and LoCoH methods. However, both methods produced similar land cover preferences within the HR and core areas. Based on IKONOS-imagery-aided evaluation, our results imply that LoCoH determines core areas in HR analysis better than the kernel method, while both methods can be used in preference analysis.

National audience

Sommaire : introduction; méthodes d'estimation des surfaces cultivées en banane; proposition technique et méthodologique (inventaire cartographique); couverture photographique aérienne; stéréorestitution planimétrique et altimétrique; première mise à jour de l'occupation du sol; mise en place d'un système de relevés GPS en mode différentiel; calcul d'un modèle numérique de terrain (MNT); apport des données RADAR du satellite ERS-2; produits cartographiques et statistiques ; conclusion.

Après avoir exposé les principes de base du GPS et les techniques de mesure, quelques exemples sont donnés pour l'élaboration d'un plan

Based on GPS readings taken four mornings running, this article uses statistical methods, taking account of observation dependence, to study bias and variance of errors. It is shown that with or without filtering based on criteria such as the number of satellites or PDOP, mean longitude and latitude values are unbiased. In the experiment carried out, filtering was used to improve the precision of longitude readings, but had a lesser effect on latitude. However, filtering can cause long delays before obtaining a reading. Replicating readings can increase their precision, provided certain operating conditions are respected.

Les trypanosomoses animales restent une des contraintes pathologiques majeures pour l'élevage en Afrique sub-saharienne. La lutte contre les principaux vecteurs de ces parasitoses (Glossina tachinoides et Glossina palpalis gambiensis) repose sur des systèmes attractifs, dont l'emploi doit être le plus ciblé possible pour être techniquement et socialement acceptables. Les objectifs du projet sont d'identifier les zones d'action prioritaires et en révélant à l'échelle du terroir les points épidémiologiquement les plus dangereux

Afin d'établir une méthodologie utilisant l'image Spot comme un outil complémentaire dans le contrôle de la nutrition minérale et de l'état général des palmeraies, on a analysé l'image Spot du 30/01/1991. Soixante-neuf parcelles représentatives localisées sur le terrain avec le GPS, Global positioning system, ont été étudiées et échantillonnées pour les caractères physiologiques, nutritionnels et pédologiques suivants : indice foliaire, hauteur des palmiers, nombre des arbres sains, malades ou morts, rendement en tonnes de régimes par ha, teneurs de N, P, K, Ca, Mg, Cl et B dans les feuilles et sols, types de sols et des pentes. Les valeurs radiométriques des 6 canaux ont été calculées pour chacune des 69 parcelles : 3 canaux bruts et 3 néocanaux créés à partir des 3 premiers par l'algorithme pour mieux illustrer certains aspects végétatifs des palmiers (indices de végétation, de brillance et de pigmentation). Deux méthodes d'analyse statistique ont été utilisées pour évaluer la relation entre les caractères des palmiers étudiés et les valeurs radiométriques correspondantes des parcelles, d'une part, par segmentation par dichotomie de l'ensemble de 69 parcelles, et d'autre part, par régression linéaire de l'une ou de plusieurs variables indépendantes pour illustrer la relation entre les caractères étudiés et la valeur radiométrique de chacun des 5 groupes d'âges (palmiers de 6 ans ou moins, 7 à 11 ans, 12 à 16 ans, 17 à 21 ans, 22 ans ou plus). Pour chacun de ces groupes d'âge, la relation est significative au niveau de .01 ou de .05 entre un ou plusieurs caractères étudiés et la valeur radiométrique des parcelles

The Global Positioning System (GPS) is a trilateration system which allows to compute the position of a receiver from the time the signals need to propagate from the satellites down to the receiver. Since the Selective Availability (SA) was turned off in 2000, the most important source of error is due to the variable delay experienced by the signals when traveling through the ionosphere. Today, the majority of GPS receivers use the L1C/A signal, the only civil signal currently transmitted by a full constellation of satellites, to compute their positions. The United States' GPS is actually only one of several Global Navigation Satellite Systems (GNSS) under development, such as the european Galileo or the Japanese Quasi-Zenith Satellite System (QZSS). In the years to come, the constellations of these new GNSS will be fully deployed, providing new modernized signals. The GPS is actually also being modernized and will provide two new civil signals, the first in the L2 band (1227.6 MHz) and the second in the L5 band (1176.45 MHz), as well as an improved version of the L1C/A signal in the L1 band (1575.42 MHz). The first fully available new civil signal will certainly be the GPS civil signal in the L2 band called the L2C signal. The availability of two civil signals in two different bands will give the opportunity to correct the ionospheric error to a great extent! However, receiving two signals located in different bands will add complexity in the receiver, particularly in the radio-frequency (RF) front-end. This is a major issue since, for the mass market, improved performances do usually not justify a higher power consumption and cost. As a consequence, the first objective of this thesis was to design a low-power dual-frequency RF front-end architecture for the L1C/A and L2C signals that could be integrated using standard CMOS technology and which would have a power consumption and performances comparable with that of state-of-the-art single-frequency GPS RF front-ends. Dual-frequency correction of the ionospheric error will also allow to improve the performances of another application of GPS called GPS timing. Indeed, the GPS provides the most precise time reference globally available anywhere on earth! As a consequence, an attractive solution to synchronize telecommunication networks consists to use the time reference provided by the GPS. However, the accuracy provided by single-frequency GPS receiver will soon not be sufficient anymore to be compliant with upcoming telecommunication standards. For this reason, the second objective of this thesis was the development of a dual-frequency RF front-end for an L1C/A + L2C GPS receiver for timing applications.