Abstract:

Monimopetalum chinense, an endemic species in China, is a deciduous woody liana species with a small geographic distribution in Anhui, Jiangxi and Hubei Province. Now it is listed as one of the Chinese national grade-2 protective wild plants. In order to describe quantitatively dynamics of M. chinense populations, four typical plots in different community types were established with contiguous grid quadrate method and field data were collected in Zongli village of Anhui Province. The time-specific life table and survivorship curve of M. chinense populations were established, and its population structure and spatial distribution pattern were analyzed with the theoretical distributing model and assembling intensity index. The results were as follows. Because of different environmental conditions, the characteristic time-specific life tables and survivorship curves of 4 populations were separately developed. The survivorship curve of populations A and D fitted between Deevey Ⅰ and Deevey Ⅱ type and had a stable structure, and that of population C was Deevey II type. However, the survivorship curve of population B fitted Deevey I type and was in the early stage of declining. In general, most M. chinense individuals in Zongli village were assembled in the 1, 2 and 3 classes, and elder ones were few. It appeared that the population was a stably developmental one with sufficient recruitment. There are two regeneration modes of M. chinense in forest: sexual and asexual reproduction, but the latter was the main mode. Common methods used for quantifying the spatial patterns were employed to detect the spatial pattern of M. chinense populations. Generally speaking, the population was clump in terms of the distribution pattern of the populations, but there was variation among various developmental stages, clump for saplings, random for adult individuals. The study of distribution patterns using different sizes of block showed that the pattern scale was near 4 m² or 16 m². The analysis indicated that numeric characteristics of M. chinense population were decided mainly by the interaction among the biological, ecological property and environmental factors and so on. The reproductive ways of M. chinense restricted greatly its spreading ability, and its rigorous habitat requirements decreased the adaptive capacity to environment change. Therefore, resistivity of M. chinense populations to the environmental disturbance was lower than what they appeared.

Key words: endangered plant, Monimopetalum chinense, time-specific life table, survivorship curve, spatial distribution pattern