贵州珍稀濒危植物皱叶瘤果茶的种群生态特征研究（英文）

Population Ecological Characteristics of the Rare and Endangered Plant Camellia rhytidophylla from Guizhou

皱叶瘤果茶(Camellia rhytidophylla)是颇具经济价值的特有濒危植物,分布于贵州高原亚地区(Ⅲ D10d)开阳县花梨镇洛旺河流域海拔573~920 m的常绿阔叶落叶混交林中,研究其种群生命特征与保育利用具有重要意义。选择皱叶瘤果茶疑似分布区(6 km^2)开展踏查,在密集分布区设置样地进行详查,分析其种群结构、动态和空间分布格局。结果表明:皱叶瘤果茶种群结构为增长型,幼龄树在种群中占的比重达46.38%,种群密度大小为幼龄树>中龄树>成年树,种群存活曲线为Deevey-Ⅲ型,死亡率曲线和消失率曲线分别在Ⅰ龄期和Ⅳ龄期出现2个高峰,随后又同时在Ⅲ龄期和Ⅵ龄期出现2个低谷。2个样地内的幼树种群在所有尺度下均呈集群分布,中龄树种群在小尺度上呈集群分布,在大尺度上则表现为随机分布,成年树种群由于人为活动干扰和生境异质性而使空间分布格局明显不同。各发育阶段的空间分布格局有较大差异,关系不密切,均表现为负相关或不相关。皱叶瘤果茶种群空间分布格局是其物种生物学特性、生境异质性及人为干扰等因素共同作用的结果,自然繁殖率极低是限制种群扩散的关键因素,生境异质性、山丘阻碍种子散布以及人类活动的干扰是其种群狭限分布的主要原因。

Camellia rhytidophylla is endemic and endangered and with important economic species, from the Ⅲ Dl0d in eastern Asia, which distributed at 573-920 m in evergreen broad-leaved deciduous mixed forest in Luowang river valley of Kaiyang county. So, it is significant to study the population characteristics, conservation and utiliza- tion. We took general survey in suspected distribution area about 6 square kilometers, set up plots in dense area, and analyzed the population structure, development and spatial distribution pattern. The results showed that the structure of C. rhytidophylla populations were increasing and the proportion of young tree in population was 46. 38%. The size of population density was young shrubs〉middle-aged shrubs〉adult shrubs. The survival curve of population was Deevey-Ⅲ model. There were 2 peaks in the Ⅰ and Ⅳ age-classes on the mortality rate curve and disappearance rate curve respectively, then there are 2 troughs in the Ⅲ and Ⅵ age -classed at the same time. The spatial distribu- tion pattern of C. rhytidophylla significantly differentiated at different stages of development, the young individuals were aggregated at all spatial scales while the middle-aged individuals were aggregated at small spatial scales and randomly distributed at larger scales. Differences in the distribution of adult individuals could be attributed to arti-ficial disturbance and habitat heterogeneity. The spatial pattern was not close in different stages of development, which all showed negative or no correlation. The spatial distribution pattern of C. rhytidophylla was the interaction of the factors, such as its biological characteristics, habitat heterogeneity, and artificial disturbance, etc.. The key factor limiting population development was low natural reproduction rate; the primary factors causing its en- demic distribution mainly included habitat heterogeneity, topographical constraints on seed dispersal and artificial disturbance.