Remote sensing of vegetation cover change in islands of the Kerguelen archipelago

• Published in: Polar Biology
• Main Authors: Robin, Marc, Chapuis, Jean-Louis, Lebouvier, Marc
• Other Authors: Littoral, Environnement, Télédétection, Géomatique (LETG - Nantes), Institut de Géographie et d'Aménagement Régional de l'Université de Nantes (IGARUN), Université de Nantes (UN)-Université de Nantes (UN)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université de Brest (UBO)-Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École pratique des hautes études (EPHE), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS), Centre d'Ecologie et des Sciences de la COnservation (CESCO), Muséum national d'Histoire naturelle (MNHN)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS), Ecosystèmes, biodiversité, évolution Rennes (ECOBIO), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)
• Format: Article in Journal/Newspaper
• Language: English
• Published: HAL CCSD 2011
• Subjects: Remote sensing; Climate change; Vegetation cover; Vegetation index; Sub-Antarctic islands; [SDE.BE]Environmental Sciences/Biodiversity and Ecology; [SDE.MCG]Environmental Sciences/Global Changes; [SHS.GEO]Humanities and Social Sciences/Geography; Antarctic; Kerguelen; Indian; Antarc*; Polar Biology
• Online Access: https://hal.archives-ouvertes.fr/hal-00666745; https://doi.org/10.1007/s00300-011-1069-z

International audience The plant communities in the Iles Kerguelen (South Indian Ocean) have been extensively modified by human activities, particularly through the deliberate release of rabbits, and the intentional or accidental introduction of several plant species. During the 1990 and 2000s, a decrease in precipitation resulted in a drastic reduction of some native plant species and in the increase in alien taxa. To monitor at a wide spatial scale the rapid changes of vegetation cover induced by summer droughts, we developed a method combining field data and satellite image analysis. A long-term field monitoring of plant communities was initiated on five small islands in 1992, and annually continued for over 15 years on a total of 161 line transects. Among these islands, the rabbit--which was the only introduced herbivore--was eradicated on three, remained on one control island, and had never been present on a second control island. We computed a linear model to link remote sensored vegetation indexes to plant cover deduced from line transects in numerous habitat types. After testing 14 vegetation indexes, we used a model based on the normalized difference vegetation index to precisely map the vegetation cover at several dates. A map of differences and spatial statistics indicated that vegetation cover, as a whole, decreased over the 15-year period. This study provides a reliable tool for long-term monitoring of the dynamics of plant cover in relation to climate change on the Iles Kerguelen.