Seed Plant Endemism on Hainan Island: A Framework for Conservation Actions

Abstract

Hainan, the second largest island of China, has the most extensive and best preserved tropical forests of this country. A network of 68 protected areas (54 of them are terrestrial) provides in situ conservation for the unique ecosystems of the island. We: (1) discuss an updated check-list of seed-plant species that are endemic to Hainan, (2) evaluate the extent to which the endemic flora has been the subject of molecular studies, and (3) investigate the conservation status of these species. We recognize 397 endemic species on the island, 271 of which are reported in the protected areas, and 144 of which have been Red-Listed (85 assigned to the Critically Endangered (40) or Endangered (45) IUCN categories). The families with the highest number of endemics are Rubiaceae (33 species), Lauraceae (27 species), and Poaceae (26 species). The island has only seven endemic genera, all of which are unispecific. Compared with other tropical islands, Hainan has a low number of endemics but our preliminary observations suggest that the island has a highly disharmonic flora when compared with that from the mainland. Nevertheless, most of the major clades of the seed-plant tree of life with representatives in China also have endemic species on the island. We argue that the low levels of endemism reflect the continental nature of Hainan and the fact that several areas of the island have not been fully inventoried. We were unable to find a single molecular systematic study focusing exclusively on the Hainan endemics; however, 24 of the endemic species have been included in phylogenetic studies targeting particular genera or families. Future research/conservation actions for the endemic flora of Hainan should focus in developing: (1) a red-list that assesses all 397 endemic species, (2) comprehensive floristic studies for the protected areas, (3) molecular phylogenetic and conservation genetic studies with a primary focus on the endemics, (4) studies to understand what ecological interactions are important in the biology of the endemic species, and (5) eco-geographical studies to identify Important Biodiversity Zones of endemism within Hainan and therefore potential new protected areas.

Tropical birds are declining in the Hainan Island of China

“…1) is located in the southernmost terrestrial portion of China, encompassing an area of approximately 33,900 km 2 . It is the largest tropical island in China and is located within the Indo-Burma biodiversity hotspot (Francisco-Ortega et al, 2010;Myers et al, 2000). The island includes 18 counties or cities.…”

“…The average annual temperature ranges from 16°C in January to 26-29°C in July. The annual precipitation is more than 1600 mm (Francisco-Ortega et al, 2010). Rainfall mainly comes from typhoons in the Pacific Ocean during the rainy season.…”

Deforestation and fragmentation of natural forests in the upper Changhua watershed, Hainan, China: implications for biodiversity conservation

“…1c). The interior uplands of the island are characterized by great habitat diversity and are one of China's most important biodiversity conservation areas (Feng et al 1999;Francisco-Ortega et al 2010). The Changhua watershed is the cradle of Hainan's main rivers (Feng et al 1999) and has been identified as a center of endemism for plants and birds (Wang et al 2006;Chen 2008).…”

Begonia wuzhishanensis (sect. Diploclinium, Begoniaceae), a new species from Hainan Island, China

“…The island harbors the Hainan Island Monsoon Rain Forest Ecoregion, one of the 26 terrestrial habitats of China internationally recognized by the World Wildlife Fund for its global ecological importance (Francisco-Ortega et al [2010]). A recent study on distribution of endangered species in China identifies southern Hainan as one of eight hotspots for plant conservation in the country (Zhang and Ma [2008]).…”