Studies On Seed Plant Biodiversity And Conservation In Main Forest Regions Of San Jiangyuan Nature Reserve, Qinghai Province

Seed plant diversity and conservation were studied in four main forest regions of San Jiangyuan Nature Reserve, including Jiangxi forest region, Baizha forest region, Ma Kehe forest region and Maixiu forest region. The objective of this paper was to provide scientific methods and theories for plant diversity conservation of San Jiangyuan Nature Reserve. The following results have been obtained in this research.(1)There were 946 seed plant species which belong to 296 genera and 66 families in four main forest regions. Tropical genera accounted for 3.49% of total genera, and temperate genera represented 90.31% in genera level, which revealed that the flora was temperate in nature. 537 plant species that were endemic to China accounted for 57.30% of total species, which indicated that endemism was dominant in species level. The seed plants flora came from the deep fusion of Hengduan Mt. Flora and Tanggute Mt. Flora, and the Hengduan Mt. Flora were the main flora for forest regions. Most plant species were perennial herbs and poor in woody; most of genera endemic to China were common to Qinghai-Tibetan Plateau Hengduan Mt. Region and Tanggute Mt. Region.(2)The quantitative assessment indices for endangerment categories and conservation priority grading of plant species of San Jiangyuan Nature Reserve were established. The quantitative assessment indices included endangerment system, genetic loss system and useful value system. Endangerment coefficient described the endangerment category and conservation priorities coefficient described the preferential conservation of plant species. The results of assessment showed that the number of endangered species was 2, such as Picea brachytyla and Sinadoxa corydalifolia. Vulnerable species 36, such as Sabina pendula, Sinopodophyllum hexandrum and Meconopsis punicea, etc. Near threatened species 140, such as Circaeaster agrestis, Anisodus tanguticus and Astragalus membranaceus, etc. Safe species 768, such as Picea likiangensis, Aconitum tanguticum and Delphinium sparsijlorum, etc. The number of the first concern species was 4, such as Picea brachytyla, Sinadoxa corydalifolia, Abies squamata and Lagotis angustibracteata. The second concern species 18, such as Abies.faxoniana, Astragalus membranaceus and Pomatosace filicula, etc. The third concern species 150, such as Picea likiangensis,Circaeaster agrestis and Sinopodophyllum hexandrum, etc., and the least concern 774, such as Koenigia islandica, Anemone rivularis and Saxifraga tangutica, etc.(3) The niche characteristics of Sinopodophyllum hexandrum, Circaeaster agrestis and a few herbaceous species were described and analyzed ,with different community types and altitude as the resource state, with the important value and abundance as the resource state descriptor of niche. The results indicated that Sinopodophyllum hexandrum, Circaeaster agrestis and Herminium monorchis have lower niche breadth values and have higher requirement of habitat. Niche overlap between a few herbaceous species were lower and only 21.43% of them had a niche overlap over 0.01, the niche overlap between Sinopodophyllum hexandrum, Circaeaster agrestis and Herminium monorchis were lowest.(4)Only a few shrub species presented positive interspecific association, most of them had little opportunity to use the same resources and occupy niche in the same community due to competion., just 104 pairs of species showed their positive correlation in the 351 pairs of shrub species. However, most of herb species could appear in the same community and presented positive interspecific association, but the degree of positive association was very weak, 118 pairs of species showed their positive correlation and and 112 pairs of species showed their negative correlation in 231 pairs of herb species.(5)Two-Way Indicators Species Analysis(TWINSPAN) and Detrended Correspondence Analysis(DCA) were used to study the distribution patterns of vegetation. TWINSPAN classification results showed that the vegetation could be divided into 4 vegetation type groups, such as coniferous for...