Living with the Sharks: A Multi-Methods Study Analyzing Human-Wildlife Conflicts as a Step Towards Coexistence (Réunion)

International audienceOn the island of Réunion, a French overseas department located in the western Indian Ocean, a prefectorial decree taken by the authorities on July 26, 2013 has been reconducted for the past 10 years to forbid swimming and water-based activities, apart from the conditions set out in the injunction. This decision was the outcome of increased shark sightings and incidents causing, in particular, the deaths of 5 ocean users between 2011 and 2013. As a preliminary attempt to address the lack of empirical research on ocean users' social representations and their relationship to non-humans, this paper aims to primarily analyze thoroughly the issues of the acceptance of shark risk mitigation options. Data were gathered through a qualitative study that mobilized several ethnographic tools such as face-to-face semi-structured interviews, participant and non-participant observation as well as social media data survey. Results indicate that the many tensions generated by shark-human interactions (SHIs) on the island of Réunion are related to a lack of public consultation, thus calling the acceptance of the shark management strategy and the scientific recommendations into question. The findings may improve shark-human interactions management as we consider the management of risk as a process to develop a well-balanced way of living with the sharks where residual risk remains. This study contributes to the advancement of knowledge on the management of human-wildlife conflicts (HWCs) while the results tend to confirm the findings of many other studies showing that they are often rooted in human-human conflicts.Sur l'île de La Réunion, département français d'outre-mer situé dans l'ouest de l'océan Indien, un arrêté préfectoral pris par les autorités le 26 juillet 2013 a été reconduit depuis 10 ans pour interdire la baignade et les activités nautiques, en dehors des conditions prévues par l'injonction. Cette décision fait suite à l'augmentation des observations de requins et des incidents, ayant notamment causés la mort de 5 usagers de l'océan entre 2011 et 2013. Afin de pallier le manque de recherches empiriques sur les représentations sociales des usagers de la mer et de leur rapport aux non-humains, cet article a pour objectif principal d'analyser en profondeur la question de l'acceptation sociale des mesures visant à réduire le risque requin. Les données ont été recueillies dans le cadre d'une étude qualitative qui a mobilisé plusieurs outils ethnographiques tels que des entretiens semi-directifs, des observations participantes et non participantes, ainsi qu'une enquête sur les données issues des réseaux sociaux. Les résultats indiquent que les nombreuses tensions générées par les interactions entre requins et humains sur l'île de La Réunion sont le fruit d'un manque de consultation du public, remettant ainsi en question l'acceptation de la stratégie de gestion du risque requin et les recommandations des scientifiques. Les résultats sont susceptibles d'améliorer la gestion des interactions entre les requins et les humains, dans la mesure où nous considérons la gestion du risque comme un processus permettant de développer un mode de vie équilibré avec les requins dans un contexte où un risque résiduel subsiste. Cette étude contribue à l'avancement des connaissances sur la gestion des conflits entre les sociétés humaines et la faune sauvage, puisque les résultats tendent à confirmer les découvertes de nombreuses autres études qui ont démontré qu'ils sont souvent enracinés dans des conflits entre humains

Correction of tropospheric effects in SAR interferometry: a comparison of ERA-Interim, ERA-5 and HRES Global Atmospheric Models

Since the 1970s, Interferometric Synthetic Aperture Radar is commonly used in Earth Sciences to construct high resolution topographic maps or to study surface displacements. The recent launch of new satellites such as Sentinel-1 constellation allows to routinely derive dense deformation maps with millimetre precision thanks to high revisit frequency and wide swath coverage (300 km wide). However, the accuracy of InSAR is still limited by atmospheric noise, as atmospheric delays may lead to subcentimeter biases in measurements. Global Atmospheric Models (GAMs) allow to compute tropospheric delay maps and correct interferograms from atmospheric delays. In the light of the development of these models over the last ten years, where spatio-temporal resolutions became finer and models more accurate, we propose a quantitative comparison of recent GAMs. We first describe how to correct interferograms from atmospheric delays and present three GAMs used in this paper: ERA-5, ERA-Interim and HRES. We then perform a statistical comparison of the performances of atmospheric corrections. We finally discuss the contribution of the enhanced spatio-temporal resolution of ERA-5, the latest global reanalysis from ECMWF, arguing that improving the spatial resolution is key toward better predictions of atmospheric delays in SAR interferometry

CorPhU: an algorithm based on phase closure for the correction of unwrapping errors in SAR interferometry

International audienceInterferometric Synthetic Aperture Radar is commonly used in Earth Sciences to study surface displacements or construct high resolution topographic maps. Recent satellites such as those of the Sentinel-1 constellation allow to derive dense deformation maps with millimetric precision with high revisit frequency. However, InSAR is still limited by interferometric coherence. Interferometric phase noise resulting from a loss of coherence, due to changes in scattering properties between repeated SAR acquisitions, may lead to unwrapping errors, which then in turn lead to centimetric errors in time series reconstruction. We present an algorithm based on interferometric phase closure to automatically correct unwrapping errors. We describe the algorithm and highlight its performances with two case studies, in Lebanon with Envisat satellite data and in Central Turkey with Sentinel-1 data. The first dataset is particularly affected by unwrapping errors because of long spatial (500 m) and temporal baseline interferograms (6 years) and decorrelation due, in particular, to vegetation. The second dataset contains unwrapping errors because of temporal changes in the scattering properties of the ground. For these two examples, the algorithm allows the correction of almost all detectable unwrapping errors, without requiring visual inspection or manual deletions. Our algorithm is efficient especially on large datasets, such as with Sentinel-1 constellation, where interferometric phase is redundant and improves eventually the reconstruction of time series

Valores, Creencias y Normas de los Prestadores de Servicios Turísticos del Parque Nacional Arrecifes de Cozumel, México

Tourist service providers (TSPs) of diving are widely benefited by the tourist attraction capacity of the “Parque Nacional Arrecifes de Cozumel” (PNAC), in the Mexican Caribbean, but the values, beliefs and norms about the conservation of the natural space are diverse, which makes it difficult to achieve a sustainable management of ecosystem services in the face of chronic tourist pressure. The objective of this research was to explore the relationships between the TSP´s values, beliefs and norms towards the conservation of the PNAC and the environmental impacts of tourism. The method of data collection was qualitative, with a triangulation that included an interview script to a sample of providers of diving tourism services and administrative collaborators of the PNAC, a focus group workshop for diagnostic with tourism service providers of diving and participant observation of diving. It was established that providers' intentions are predetermined by systems of external influences, regulated by more influential social peer groups. The results are useful for designing public conservation policies and good environmental practices for tourism development and ecosystem uses in the PNAC.Los prestadores de servicios turísticos (PST) de buceo son ampliamente beneficiados por la capacidad de atracción turística del Parque Nacional Arrecifes de Cozumel (PNAC), en el Caribe mexicano, pero los valores, creencias y normas acerca de la conservación del espacio natural son diversas, lo cual dificulta lograr una gestión sostenible de los servicios ecosistémicos frente a la presión turística crónica. El objetivo de esta investigación fue analizar las relaciones entre servicio turístico y los valores, creencias y normas de los PST hacia la conservación del PNAC. El método de recolección de datos fue con un grupo focal de prestadores de servicios turísticos de buceo y colaboradores administrativos del PNAC. Se estableció que las intenciones de los prestadores están predeterminadas por sistemas de influencias externos, regulados por grupos de pares sociales más influyentes. Los resultados son útiles para diseñar políticas públicas de conservación y buenas prácticas ambientales para el aprovechamiento turístico y los usos ecosistémicos en el PNAC

Valores, Creencias y Normas de los Prestadores de Servicios Turísticos y conservación del Parque Nacional Arrecifes de Cozumel, México

International audienceTourist service providers (TSPs) of diving are widely benefited by the tourist attraction capacity of the “Parque Nacional Arrecifes de Cozumel” (PNAC), in the Mexican Caribbean, but the values, beliefs and norms about the conservation of the natural space are diverse, which makes it difficult to achieve a sustainable management of ecosystem services in the face of chronic tourist pressure. The objective of this research was to explore the relationships between the TSP´s values, beliefs and norms towards the conservation of the PNAC and the environmental impacts of tourism. The method of data collection was qualitative, with a triangulation that included an interview script to a sample of providers of diving tourism services and administrative collaborators of the PNAC, a focus group workshop for diagnostic with tourism service providers of diving and participant observation of diving. It was established that providers' intentions are predetermined by systems of external influences, regulated by more influential social peer groups. The results are useful for designing public conservation policies and good environmental practices for tourism development and ecosystem uses in the PNAC.Los prestadores de servicios turísticos (PST) de buceo son ampliamente beneficiados por la capacidad de atracción turística del Parque Nacional Arrecifes de Cozumel (PNAC), en el Caribe mexicano, pero los valores, creencias y normas acerca de la conservación del espacio natural son diversas, lo cual dificulta lograr una gestión sostenible de los servicios ecosistémicos frente a la presión turística crónica. El objetivo de esta investigación fue explorar las relaciones entre los valores, creencias y normas de los PST hacia la conservación del PNAC y los impactos ambientales del turismo. El método de recolección de datos fue cualitativo, con una triangulación que incluyó un guion de entrevista a una muestra de prestadores de servicios turísticos de buceo y colaboradores administrativos del PNAC, un taller de enfoque grupal de diagnóstico a prestadores de servicios turísticos de buceo y observación participante de buceo. Se estableció que las intenciones de los prestadores están predeterminadas por sistemas de influencias externos, regulados por grupos de pares sociales más influyentes. Los resultados son útiles para diseñar políticas públicas de conservación y buenas prácticas ambientales para el aprovechamiento turístico y los usos ecosistémicos en el PNAC

Valores, Creencias y Normas de los Prestadores de Servicios Turísticos y conservación del Parque Nacional Arrecifes de Cozumel, México

International audienceTourist service providers (TSPs) of diving are widely benefited by the tourist attraction capacity of the “Parque Nacional Arrecifes de Cozumel” (PNAC), in the Mexican Caribbean, but the values, beliefs and norms about the conservation of the natural space are diverse, which makes it difficult to achieve a sustainable management of ecosystem services in the face of chronic tourist pressure. The objective of this research was to explore the relationships between the TSP´s values, beliefs and norms towards the conservation of the PNAC and the environmental impacts of tourism. The method of data collection was qualitative, with a triangulation that included an interview script to a sample of providers of diving tourism services and administrative collaborators of the PNAC, a focus group workshop for diagnostic with tourism service providers of diving and participant observation of diving. It was established that providers' intentions are predetermined by systems of external influences, regulated by more influential social peer groups. The results are useful for designing public conservation policies and good environmental practices for tourism development and ecosystem uses in the PNAC.Los prestadores de servicios turísticos (PST) de buceo son ampliamente beneficiados por la capacidad de atracción turística del Parque Nacional Arrecifes de Cozumel (PNAC), en el Caribe mexicano, pero los valores, creencias y normas acerca de la conservación del espacio natural son diversas, lo cual dificulta lograr una gestión sostenible de los servicios ecosistémicos frente a la presión turística crónica. El objetivo de esta investigación fue explorar las relaciones entre los valores, creencias y normas de los PST hacia la conservación del PNAC y los impactos ambientales del turismo. El método de recolección de datos fue cualitativo, con una triangulación que incluyó un guion de entrevista a una muestra de prestadores de servicios turísticos de buceo y colaboradores administrativos del PNAC, un taller de enfoque grupal de diagnóstico a prestadores de servicios turísticos de buceo y observación participante de buceo. Se estableció que las intenciones de los prestadores están predeterminadas por sistemas de influencias externos, regulados por grupos de pares sociales más influyentes. Los resultados son útiles para diseñar políticas públicas de conservación y buenas prácticas ambientales para el aprovechamiento turístico y los usos ecosistémicos en el PNAC

Les bois de Tapia de Madagascar: approches phytogéographique, floristique et écologique

Ce chapitre a trois objectifs. En premier lieu, il rappelle que les formations végétales à dominance de tapia sont distribuées en quatre ensembles sur les « Hautes Terres malgaches ». En second lieu, à partir d’un examen global de la littérature et de relevés floristiques effectués dans deux des entités, à savoir Arivonimamo et Ambatofinandrahana, il dresse une liste actualisée de la diversité floristique des bois de tapia. Celle-ci est partiellement illustrée par un support photographique et des planches sur un CD-ROM qui reprend également les noms vernaculaires des taxons considérés. Enfin une approche écologique préliminaire est effectuée sur base des groupements végétaux et/ou des niches écologiques de certains taxons inventoriés.This chapter has three objectives. Firstly, it is emphasized that tapia-dominated areas are spatially distributed into four localities situated on the so-called “Highlands”. Secondly, based on a global survey of available literature on tapia vegetation as well as on floristic surveys carried out in two entities (Arivonimamo et Ambatofinandrahana), an actualized list of their floristic diversity is composed. This list is partially illustrated with photographs and plates on a CD-ROM; vernacular names of the considered taxa are quoted. Finally a preliminary ecological interpretation is given based on the vegetation units and (or) ecological niches which are schematically represented

A Simple Phase Unwrapping Errors Correction Algorithm Based on Phase Closure Analysis

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Long-term growth of the Himalaya inferred from interseismic InSAR measurement

International audienceThe rise and support of the ~5000 m topographic scarp at the front of Indian-Eurasian collision in the Himalaya involves long-term uplift above a mid-crustal ramp within the Main Himalayan Thrust (MHT) system. Locking of the shallower portion of the flat-ramp-flat during the interseismic period also produces transient uplift above the transition zone. However, spatial and temporal relationships between permanent and transient vertical deformation in the Himalaya are poorly constrained, leading to an unresolved causal relationship between the two. Here, we use synthetic aperture radar interferometry (InSAR) to measure interseismic uplift on a transect crossing the whole Himalaya in Central Nepal. The uplift velocity of 7 mm/yr at the front of the Annapurnas is explained by a 18–21 mm/yr slip rate on the deep shallow-dipping portion of the MHT, with full locking of the mid-crustal ramp underlying the High Range. The transient uplift peak observed by InSAR matches spatially with the long-term uplift peak deduced from the study of trans-Himalayan rivers incision, although models of the seismic cycle involving thrusting over a ramp of fixed geometry predict a ~20 km separation between the two peaks. We argue that this coincidence indicates that today’s mid-crustal ramp in Central Nepal is located southward with respect to its average long-term location, suggesting that mountain growth proceeds by frontward migration of the ramp driven by underplating of material from the Indian plate under the Himalaya

Presentation of the Small Baselin NSBAS Processing Chain on a Case Example : The Etan Deformation Monitoring from 2003 to 2010 Using Envisat Data

International audienceWe assemble a processing chain that handles InSAR computation from raw data to time series analysis. A large part of the chain (from raw data to geocoded unwrapped interferograms) is based on ROI PAC modules (Rosen et al., 2004), with original routines rearranged and combined with new routines to process in series and in a common radar geometry all SAR images and interferograms. A new feature of the software is the range-dependent spectral filtering to improve coherence in interferograms with long spatial baselines. Additional components include a module to estimate and remove digital elevation model errors before unwrapping, a module to mitigate the effects of the atmospheric phase delay and remove residual orbit errors, and a module to construct the phase change time series from small baseline interferograms (Berardino et al. 2002). This paper describes the main elements of the processing chain and presents an example of application of the software using a data set from the ENVISAT mission covering the Etna volcano