Gaucherel C.,French National Institute for Agricultural Research |
Balasubramanian M.,French Institute of Pondicherry IFP |
Karunakaran P.V.,French Institute of Pondicherry IFP |
Ramesh B.R.,French Institute of Pondicherry IFP |
And 4 more authors.
Journal of Zoology | Year: 2010
In spatial ecology, detailed covariance analyses are useful for investigating the influences of landscape properties on fauna and/or flora species. Such ecological influences usually operate at multiple scales, involving biological levels from individual to group, population or community and spatial units from field to farms and regions. The aim of this work was to analyze possible multiscale influences of some landscape properties on elephant distribution in the Western Ghats, India, by applying a recent and simple mathematical method to quantify such ecological relationships across space and scales. This method combines a moving window with various correlation indices to investigate the relationship between two mapped variables. Maps of landscape heterogeneity (quantified here at all locations of the landscape with a modified Shannon index) and Asian elephant presence (a two-dimensional presence probability) were significantly correlated. This correlation systematically decreased with increasing scales (i.e. sizes of the reference moving window). Yet, this global relationship includes both positive and negative correlations located at distinct places. We documented a positive feedback (reinforcement) because elephants appeared to seek greater habitat heterogeneity, in heterogeneous areas, such as along the interface between natural and a human-disturbed habitat or in the natural part of the studied landscape. In parallel, we observed a negative feedback (compensation) making elephants seeking more homogeneous places in some relatively heterogeneous zones. Such negative feedbacks corresponded to higher than average probabilities of elephant presence. Finally, when elephant density varied according to landscape heterogeneity (corresponding to significant correlations), it pointed towards swamps and grasslands, but not towards semi-evergreen or secondary forests (as it may have been expected). Land cover information appeared to be less relevant than an integrated heterogeneity index computed at all scales. © 2009 The Authors. Journal compilation. © 2009 The Zoological Society of London.
Hardy O.J.,Roosevelt University |
Couteron P.,IRD Montpellier |
Munoz F.,IRD Montpellier |
Ramesh B.R.,French Institute of Pondicherry IFP |
And 2 more authors.
Global Ecology and Biogeography | Year: 2012
Aim We addressed the roles of environmental filtering, historical biogeography and evolutionary niche conservatism on the phylogenetic structure of tropical tree communities with the following questions. (1) What is the impact of mesoclimatic gradients and dispersal limitation on phylogenetic turnover and species turnover? (2) How does phylogenetic turnover between continents compare in intensity with the turnover driven by climatic gradients at a regional scale? (3) Are independent phylogenetic reconstructions of the mesoclimatic niche of clades congruent between continents? Location Panama Canal Watershed and Western Ghats (India), two anciently divergent biogeographic contexts but with comparable rainfall gradients. Methods Using floristic data for 50 1-ha plots in each region, independent measures of phylogenetic turnover (Π ST) and species turnover (Jaccard) between plots were regressed on geographic and ecological distances. Mesoclimatic niches were reconstructed for each node of the phylogeny and compared between the two continents. Results (1) The phylogenetic turnover within each region is best explained by mesoclimatic differences (environmental filtering), while species turnover depends both on mesoclimatic differences and geographic distances (dispersal limitation). (2) The phylogenetic turnover between continents (Π ST=0.009) is comparable to that caused by mesoclimatic gradients within regions (Π ST=0.010) and both effects seem cumulative. (3) Independent phylogenetic reconstructions of the mesoclimatic niches were strongly correlated between the two continents (r=0.61), despite the absence of shared species. Main conclusions Our results demonstrate a world-wide deep phylogenetic signal for mesoclimatic niche within a biome, indicating that positive phylogenetic turnover at a regional scale reflects environmental filtering in plant communities. © 2012 Blackwell Publishing Ltd.
Richard-Ferroudji A.,French Institute of Pondicherry IFP |
Faysse N.,Asian Institute of Technology |
Bouzidi Z.,Moulay Ismaï University |
T.P. Menon R.,Pondicherry Science Forum CERD |
Rinaudo J.-D.,Bureau de Recherches Géologiques et Minières
Current Opinion in Environmental Sustainability | Year: 2016
In the past decades, groundwater over-exploitation has increased the vulnerability of users, social inequalities and environmental degradation. In this context, the DIALAQ project aimed to experiment and disseminate a participatory approach intended to strengthen stakeholders' capacity to implement more sustainable agricultural and groundwater management. DIALAQ's network encompasses 8 regions in 4 countries (India, Morocco, France and the United States) including groups of farmers, administration's representatives, NGOs, elected representatives and researchers from several disciplines. A seed funding enabled cooperation between academics and non-academic partners that led to the consolidation of the network and enabled the design of the project. Firstly, a focused review of literature on participatory foresight exercises in the field of groundwater management is presented. Secondly, the challenges and pathways taken in designing the research is described. This process resulted in a common methodological and ethical framework presented in conclusion. © 2016 Elsevier B.V.
Gaucherel C.,French Institute of Pondicherry IFP |
Grimaldi V.,French Institute of Pondicherry
Journal of Vibration and Acoustics, Transactions of the ASME | Year: 2015
Rainfall, one of the most important resources for all life and for the environment, is also the most difficult meteorological parameter to measure, mainly due to its nonstationnarity in space and time. Several powerful instruments exist today to measure rainfall, but they often suffer from some strong disadvantages, ranging from high costs and variable space and time coverage to low accuracy. In this study, we explain how a measure the sound of the falling rain could provide a reliable metric of the rainfall. We demonstrate its reliability in a specific case study, for a long rainy tropical event of the Indian monsoon and in noisy conditions. The final determination coefficient computed in cross validation reaches R2=0.9, without any treatment of the signals other than a simple smoothing window. If confirmed through more intensive research, our findings could help in the design of a highly useful acoustic rain gauge, of great value to developing countries that experience intense but poorly studied rainy seasons. Copyright © 2015, ASME. All rights reserved.