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Classification, Phytogeography And Conservation Of The Pteridophytes From Hainan Island

Posted on:2005-06-10Degree:DoctorType:Dissertation
Country:ChinaCandidate:S Y DongFull Text:PDF
GTID:1100360152471702Subject:Botany
Abstract/Summary:PDF Full Text Request
Based on extensive fieldwork and study of herbaria collections, the pteridophytes of Hainan Island were taxonomically revised. The characteristics and origin of the Hainan pteridophyte flora was also analyzed. The 439 pteridophyte taxa in Hainan were evaluated according to IUCN Red List 2001 categories and criteria. In addition, the conservation status of all threatened species was reported and documented, and proposals to conserve selected threatened taxa were also presented. The results are summarized as follows:1. 439 taxa (421 species, 15 varieties, 2 subspecies and 1 form) of 140 genera in 56 families are recognized from Hainan Island. Among them, one species is new record to China, 27 taxa are new records to Hainan, one is a new species (Teratophyllum hainanense). In addition, 11 scientific names are treated as synonyms for the first time, the types of Phymatopteris hainanensis and P. obtusa are clarified; the lectotypes are respectively designated for Ataxipteris dianguiensis, Microlepia ampla and Phymatopteris hainanensis.2. The Hainan pteridophyte flora is characterized by:i. five predominat families — Polypodiaceae, Thelypteridaceae, Aspleniaceae, Tectariaceae and Angiopteridaceae;ii. tropical distribution elements — represented by 97.5% tropical families, 92.5% tropical genera and 83.6% tropical species;iii. abundant species diversity and a great species density, but small species number within genera;iv. the most close relation with the pteridophyte flora of Indochina — of the 140 pteridophyte genera in Hainan, 136 also occur in Indochina, the similarity coefficient between Hainan and Indochina reaches to 87.2%;v. native origin — natively originated from Palaeozoic landmass Cathaysia, the origin time is at least before Early Carboniferous.3. Of the 439 pteridophyte taxa in Hainan, 183 are common, 113 are Data Deficient (DD), 47 are Near Threatened (NT), 53 are Vulnerable (VU), 37 are Endangered (EN) and 6 are Critically Endangered (CR). The threatened species numbered 96. Most of the threatened species in Hainan have been protected, for they grow in nature reserves and/or protected forests area. Besides for the biological and ecological factors, and the species distribution limitation, the main reason for the 96 threatened species in Hainan Island is the human activities, especially the severe disafforestation during the last century. In order to conserve the 96 threatened species, three measures are urgent: to strengthen the management of the nature reserves and forests in Hainan, to protect the threatened species on the spot (in-site conservation), to take actions of ex-site conservation.
Keywords/Search Tags:Pteridophyte flora, Taxonomic revision, Floristic characteristics, Conservation, Hainan Island
PDF Full Text Request
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