Identifying and mapping biodiversity processes for conservation planning in islands: A case study in Réunion Island (Western Indian Ocean)

• Published in: Biological conservation Vol. 142; no. 7; pp. 1523 - 1535
• Main Authors: Lagabrielle, Erwann, Rouget, Mathieu, Payet, Karine, Wistebaar, Nokuthula, Durieux, Laurent, Baret, Stéphane, Lombard, Amanda, Strasberg, Dominique
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier Ltd 01.07.2009; Elsevier
• Subjects: Animal, plant and microbial ecology; Applied ecology; Biological and medical sciences; Biological processes; Conservation, protection and management of environment and wildlife; Corridors; Fundamental and applied biological sciences. Psychology; General aspects. Techniques; Integrated conservation planning; Island biogeography; Land use modelling; Life Sciences; Marine; Methods and techniques (sampling, tagging, trapping, modelling...); Parks, reserves, wildlife conservation. Endangered species: population survey and restocking; Socio-economic cost; Vegetal Biology; Reunion island; Indian Ocean; Indian Ocean Islands; ISW, Indian Ocean, Mascarene Is., Reunion; Integrated conservation planning; Corridors; Land use modelling; Socio-economic cost; Biological processes; Island biogeography; Costs; Conservation; Biogeography; Biodiversity; Modeling; Socioeconomics; Land use; Case study; Marine environment; Planning; Environmental protection
• ISSN: 0006-3207; 1873-2917
• DOI: 10.1016/j.biocon.2009.02.022

Over the last century, island biodiversity has become one of the most threatened in the world. Although many island conservation plans address biodiversity requirements at the species level, few plans address the spatial requirements of the biodiversity processes that underpin the persistence of these species. Using systematic conservation planning principles, we map the spatial components of biodiversity processes (SCBPs) and use these to design broad-scale conservation corridors for Réunion Island. Our method is based upon a literature review, expert knowledge, spatially explicit base data, conservation planning software, and spatial modelling. We combine a target-driven algorithm with least-cost path analyses to delineate optimal corridors for capturing key biodiversity processes while simultaneously considering biodiversity pattern targets, conservation opportunities, and future threats. We identify five SCBPs: the oceanic–terrestrial interface; riverine corridors; macrohabitat interfaces; the boundaries of isolated topographic units; and lowland–upland gradients. A large proportion of the SCBPs (81.3%) is currently untransformed, whereas 3% is irreversibly transformed by urbanisation and 15.7% is transformed but restorable. However, SCBPs are almost fully disrupted by urbanisation in the lowlands, thereby compromising functional corridors along full altitudinal gradients. This study is a contribution toward the reconciliation of conservation versus development objectives on Réunion Island but we believe that the delineation method is sufficiently general to be applied to other islands. Our results highlight the need for integrating marine, coastal and terrestrial conservation planning as a matter of urgency, given the rapid transformation of coastal areas on islands.