Coconut synthesis report on gaps for priority collecting and conservation : technical report LOA 2014/44

• Main Authors: Coppens d'Eeckenbrugge, G., Wolf, V., Baudoin, L., Depraetere, Christian
• Format: Text
• Language: English
• Published: Biodiversa 2015
• Subjects: Antarctic; West Antarctic Ice Sheet; Pacific; Antarc*; Ice Sheet
• Online Access: http://www.documentation.ird.fr/hor/fdi:010067234

Based on the information available from COGENT, important gaps persist in the affiliated germplasm collections, e.g. for large parts of Polynesia, Melanesia, Micronesia, Australia, Indonesia, Malaysia, India, Myanmar, Madagascar, Kenya and Somalia, among regions where coconut is likely to be native. SSR marker data for 86 coconut populations were analyzed to study the distribution of genetic diversity, using Jost’s J1 index. The Indo-Pacific region presents the highest diversity, with hotspots in Vanuatu, Papua New Guinea, South East Asia, and East Africa. Atlantic shores, where the coconut was introduced in historical times, appear less diverse. However, this picture is incomplete, as many neighboring areas correspond to gaps in collections and genetic studies. The potential impact of climate change on coconut distribution was anticipated for the year 2050, using three climate models (BCC-CSM1-1, CCSM4, and HadGEM2-ES) and three gas emission/radiative forcing scenarios (rcp4.5, rcp6.0, and rcp8.5). All results converge in predicting a very strong increase of areas climatically suitable for the coconut, thus discarding a global negative impact of climate change per se. This seems reassuring in terms of genetic erosion risk, as well as production. However, a few regions, including southeastern India and Bangladesh, would be negatively affected. Due the eastward shift of favorable areas around the Bay of Bengal, Bangladesh could lose about half of his coconut production areas. The 0.2-0.4m sea-level rise expectation for 2000-2050 might be doubled in case the West Antarctic Ice Sheet has already been set into motion. Even so, its impact on coastal coconut populations should be negligible for continents and large islands, where shoreline retreat should be modest, compared to the extension of climatically suitable areas. The situation would be different for distant, small and low-lying islands, as well as delta areas, particularly in the Indo-Pacific region, where rising rates are up to thrice the global rate. Thus, there are severe threats on the Maldives, Laccadive, and Mascarene archipelagos, and on the myriad of far Polynesian, Micronesian, and Melanesian islands, all regions hosting an important diversity of coconut germplasm, not well studied so far. Flooding threats will increase on the shores of eastern India and the Bay of Bengal, increasing the pressure on coconut and people.