20 research outputs found

    Madagascan day geckos (Phelsuma spp.) exhibit differing responses along a gradient of land-use change

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    Madagascar is a key priority for global conservation efforts, as much of its diverse and highly endemic biota is threatened by deforestation. Despite this threat, there are limited data on the responses and tolerances of herpetofaunal species to landscape change. This study investigated the response of Madagascan day geckos (Phelsuma spp.) to deforestation in Nosy Be, Madagascar. We selected six sites along a gradient of land-use change: two in Sambirano rainforest (“Forest”), two in secondary, fragmented forest (“Fragment”), and two in agricultural plantations (“Orchard” and “Cropland”). We conducted a series of time-constrained searches at each site. The mean encounter rate of Phelsuma geckos (geckos detected per person/hour) was greater in agricultural sites than Forest sites, but no difference was detected between Forest and Fragment or Fragment and agricultural areas. Three species were encountered more frequently in agricultural land than forested sites, but this was not true for Phelsuma seippi, an endangered species on the IUCN Red List. These results suggest that adaptive, generalist species may benefit from anthropogenic land-use change, whereas specialist species will suffer. Our study emphasizes the importance of extending research beyond the borders of protected forests to include anthropogenically disturbed areas

    Here be dragons: important spatial uncertainty driven by climate data in forecasted distribution of an endangered insular reptile

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    International audienceThe effect of future climate change is poorly studied in the tropics, especially in mountainous areas, yet species living in these environments are predicted to be strongly affected. Newly available high-resolution environmental data and statistical methods enable the development of forecasting models, but the uncertainty related to climate models can be strong, which can lead to ineffective conservation actions. Predictive studies aimed at providing conservation guidelines often account for a range of future climate predictions (climate scenarios and global circulation models). However, very few studies consider potential differences related to the source of climate data and/or do not account for spatial information (overlap) in uncertainty assessments. We modelled the environmental suitability for Phelsuma borbonica, an endangered reptile native to Reunion Island. Using two metrics of species range change (difference in overall suitability and spatial overlap), we quantified the uncertainty related to the modelling technique (n = 10), sample bias correction, climate change scenario, global circulation models (GCM) and data source (CHELSA vs. Worldclim). Uncertainty was mainly driven by GCMs when considering overall suitability, while for spatial overlap, the uncertainty related to data source became more important than that of GCMs. The uncertainty driven by sample bias correction and variable selection was much higher when assessed based on the spatial overlap. The modelling technique was a strong driver of uncertainty in both cases. We provide a consensus ensemble prediction map of the environmental suitability of P. borbonica to identify the areas predicted to be the most suitable in the future with the highest certainty. Predictive studies aimed at identifying priority areas for conservation in the face of climate change need to account for a wide panel of modelling techniques, GCMs and data sources. We recommend the use of multiple approaches, including spatial overlap when assessing uncertainty in species distribution models

    Multifrequency Radar Observations Collected in Southern France during HyMeX-SOP1

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    International audienceThe radar network deployed in Southern France during the first Special Observing Period (SOP1) of the Hydrometeorological Cycle in the Mediterranean Experiment (HyMeX) was designed to precisely document the 3-D structure of moist upstream flow impinging on complex terrain as a function of time, height and along-barrier distance as well as surface rainfall patterns associated with orographic precipitation events. This deployment represents one of the most ambitious field experiments yet endeavoring to collect high quality observations of thunderstorms and precipitation systems developing over and in the vicinity of a major mountain chain. Radar observations collected during HyMeX represent a valuable, and potentially unique, dataset that will be used to improve our knowledge of physical processes at play within coastal orographic heavy precipitating systems as well as to develop, and evaluate, novel radar-based products for research and operational activities. This article provides a concise description of this radar network and discusses innovative research ideas based upon preliminary analyses of radar observations collected during this field project with emphasis on the synergetic use of dual-polarimetric radar measurements collected at multiple frequencies

    Characteristics of buyers and renters of cultural goods: the case of movies

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    This article identifies the characteristics of consumers of movies, watched on videotapes, in their homes. Models of the frequency of movie video buying and renting by individuals are estimated using data from the Spanish Cultural Consumption Habits Survey (Encuesta sobre Habitos de Consumo Cultural). This survey featured information about videotapes rented and bought in Spain throughout 1998. Applying a multinomial probit modelling framework, this study analyses whether there are two different video markets (renting and buying) and any discernible socio-economic characteristics for their respective consumers. The influence of film genres on the renting of movie videotapes is also considered.

    Overview of the Meso-NH model version 5.4 and its applications

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    This paper presents the Meso-NH model version 5.4. Meso-NH is an atmospheric non hydrostatic research model that is applied to a broad range of resolutions, from synoptic to turbulent scales, and is designed for studies of physics and chemistry. It is a limited-area model employing advanced numerical techniques, including monotonic advection schemes for scalar transport and fourth-order centered or odd-order WENO advection schemes for momentum. The model includes state-of-the-art physics parameterization schemes that are important to represent convective-scale phenomena and turbulent eddies, as well as flows at larger scales. In addition, Meso-NH has been expanded to provide capabilities for a range of Earth system prediction applications such as chemistry and aerosols, electricity and lightning, hydrology, wildland fires, volcanic eruptions, and cyclones with ocean coupling. Here, we present the main innovations to the dynamics and physics of the code since the pioneer paper of Lafore et al. (1998) and provide an overview of recent applications and couplings
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