December 2013 Vol.58 Suppl.Ⅰ: 126133 www.scichina.com csb.scichina.com Citation: Limaye R B, Kumaran K P N. Biogeographical and palaeoclimate appraisal of mangrove vegetation in South Asia and Southeast Asia in the post Himalayan uplift scenario. Chin Sci Bull(Chin Ver), 2013, 58(Suppl. I):126–133, doi: 10.1360/tb-2013-suppl009 ȧ中国科学Ȩ杂志社 SCIENCE CHINA PRESS Article Biogeographical and palaeoclimate appraisal of mangrove vegetation in South Asia and Southeast Asia in the post Himalayan uplift scenario LIMAYE Ruta Bharat & KUMARAN Krisnamenon Palghat Navnith * Palynology and Palaeoclimate Laboratory, Palaeobiology Group, Agharkar Research Institute, G G Agarkar road, Pune 411004, India *Corresponding author (email: kpnkumaran@gmail.com) Received April 11, 2013; accepted August 8, 2013 Fossil evidence indicates that mangrove species have had their first appearance in the Late Cretaceous (70−65 Ma) and they have evolved around the Tethys seaway after the plate tectonics and the movement of the continents when Tethys Sea was fast closing as the massive continental fragments continued to shift and jostle across the globe. The oldest geological record of Acrostichum and Nypa palm offers good examples as these species prefer low-salinity requirements and have wide ecological tolerance. Such environmental and habitat preferences must have been the probable reason for their initial adaptation to mangrove habitat and a wider distribution. The open sea link must have also provided enough coastal areas for the establishment of mangrove ecosystem and subsequent spreading of the mangroves into newer areas by Early to Middle Eocene (ca 50–40 Ma). However, the mangroves started acquiring the present geographical positions towards Oligocene- Middle Miocene period. The fossil record and the modern analogues of Kandelia, Nypa and Pelliciera indicate that their biogeographical preferences have been shifted due to oceanic reorganization wherein the latter is now confined only to Atlantic East Pacific mangrove realm despite it was earlier widespread in the Tethys Sea. Although Rhizophora and Avicennia differ only at the species level and common occurrence of Acrostichum aureum, the present mangrove distribution shows the contrast in the biogeography of many genera due to geomorphic barriers and climatic changes. The Himalayan uplift and establishment of Asian summer monsoon system towards Late Neogene has also affected the coastal dynamics considerably which in turn modified the distribution of mangrove vegetation of the Indian subcontinent. The loss of sensitive habitats, disjunct distribution of a few species and local extinction of significant taxa has affected the overall biogeography of mangroves in South and SE Asia. Palaeomangroves, modern analogues, biogeography, Palaeoclimate, South and Southeast Asia, Himalayan uplift Mangroves constitute the major components of the coastal ecosystem and are associated with the intertidal habitat in the tropical and subtropical regions approximately be- tween 30°N and 30°S latitude of the world. They are found in 123 countries and territories globally and cover a total of 152000 square kilometers. There are approximately 73 species and hybrids of mangroves distributed world wide. Of the total mangrove coverage, 41.4% exists in South and Southeast Asia. Global distribution of mangroves is based on major biogeographical regimes–Indo-West Pa- cific (IWP), or eastern group, extending from East Africa eastwards to the islands of the central Pacific; and the At- lantic East Pacific (AEP), or western group, including all of the Americas, West and Central Africa [1]. Among the major mangroves Nypa and Kandelia are found in the for- mer while Pelliciera is restricted to the later and Acrostichum aureum is common to both regimes. Luxuri- ant patches of mangroves are found in all the other conti- nents but the best mangroves are found in Indo-West Pa- cific region in Asia especially in India and Bangladesh. The Sundarbans have the largest mangrove forests in the world both in size as well as biodiversity and the Niger Delta, deltaic coastline of northern Brazil and Southern Papua contain rest of the major mangrove forests. The benefits obtained from these mangrove ecosystems include a variety of economic, environmental and social aspects, including carbon sequestration for combating global warm- ing [2] and protection from erosion, floods, cyclones, ty- phoons and tidal waves [3]. The mangrove forests help stabilize shorelines and reduce the devastating impact of