都支杜鹃地理分布及种群现状分析

在查阅相关文献及标本的基础上,对杜鹃属(Rhododendron L.)种类都支杜鹃(R.shanii Fang)的地理分布和种群现状进行了全面调查分析,并对该种的濒危级别进行了评价.结果表明:都支杜鹃为大别山狭域分布种,分布范围仅限于安徽省岳西县、霍山县与湖北省英山县三县交界处面积110 km2的狭长区域内,主要生于海拔1400m以上的山脊或靠近山脊的山坡上.目前仅存11个自然种群,种群占有面积总和1.2 km2；其中含有成年个体的种群有10个,成年个体总数仅存约5 400株；种群中幼体和亚成体数量远少于成年个体且大多分布于种群的边缘地带.各种群的面积和规模差别悬殊；最大种群占有面积40 hm2,最小种群占有面积2 hm2;成年个体数量上千的种群有2个,个体数量不超过100株的种群有3个.该种的地理分布呈不连续分布,生境片断化明显.根据调查结果及IUCN濒危物种红色名录分级标准,可确定都支杜鹃濒危级别至少应为易危级(vulnerable,VU).

Analyses of geographical distribution and population status of Rhododendron shanii

On the basis of consulting documents and specimens,geographical distribution and population status of Rhododendron shanii Fang in Rhododendron L.were comprehensively investigated and analyzed,and also its endangered level was evaluated.The results show that R.shanii is a narrowly distributed species in the Dabie Mountain,its distribution range is only limited to a long and narrow zone with an area of 110 km2 in the junction district of Yuexi County,Huoshan County in Anhui Province and Yingshan County in Hubei Province,and mainly distributes on the ridge or on the slope near the ridge at altitude over 1 400 m.At present,there are only 11 natural populations of R.shanii with total occupancy area of 1.2 km2.In which,10 populations contain adult individuals and the total number of adults is only about 5 400.In R.shanii populations,the number of seedlings and sub-adult individuals is much less than that of adult individuals,and they mostly distribute in edge regions of populations.There are obviously differences in occupancy area and population size.The occupancy area of the biggest population is 40 hm2 and that of the smallest population is 2 hm2.There are two populations containing thousands of adult individuals,while there are three populations containing no more than 100 adult individuals.The geographical distribution of R.shanii is discontinuous and its habitat is obviously fragmented.According to these investigation results and classification standard of IUCN endangered species red list,it is determined that the endangered level of R.shanii should be vulnerable grade(VU) at least.