Structure And Dynamic Characteristics Of Key Protected Wild Plants In Wan-ning City, Hainan

Due to the impact of human activities and natural factors, natural vegetation is compressed; the distribution, population dynamics characteristics and landscape types of all kinds of wild plants change a lot. Taking the city (county) field as a unit, this paper adopted the "quadrat method" and "actual measuring" to conduct field investigations on key protected wild plants in Wanning City, and analyzed the relations between the terrain factor and key protected wild plants in Hainan Province. Dimocarpus longan, Vatica mangachapoi, Heritiera parvifolia, Hydnocarpus hainanensis were taken as examples, and spatial distribution pattern, population diameter structure, static life table, and survival curve were used to analyze the population of Dimocarpus longan, Vatica mangachapoi, Heritiera parvifolia, Hydnocarpus hainanensis. In addition, Litchi chinensisas was taken as an example in this article to comparatively analyze the distribution patterns and population dynamics both inside and outside the natural conservation area to reveal the population distribution and the trend of population dynamics of wild litchi, thus providing the basis for the protection of wild litchi resources. The results showed that:(1) The results indicated that 23 state key protected wild plants were found totally in Wanning City, accounting for key protected wild plants in China (a total of 307 kinds) of 5.86%, accounting for key protected wild plants (a total of 43 kinds) in Hainan of 42.86%, showing the relative abundance of key protected wild plants resources; The key protected wild plants distributed around 200-300m and the number of species distributed most widely species on shady, half shade slope and gentle slope.(2) The results of population dynamics and distribution patterns showed that:the growth type of the key protected wild plants population was different. For example Dimocarpus longan population and Heritiera parvifolia population were stable-growth model; Vatica mangachapoi population was slow-growth model; Hydnocarpus hainanensis population was an unstable-growth model; while uniform distribution pattern was also appeared such as Dimocarpus longan population.(3) Litchi chinensis taken as an example in this article to comparatively analyze the distribution patterns and population dynamics both inside and outside the natural conservation areas. The research results of Distribution pattern showed that:the wild litchi population both inside and outside the natural reserves were aggregated distribution, and the aggregation degree of the non-natural conservation area was more obvious than that of the natural conservation area. The results of population dynamics characteristics showed that:the population structure of wild litchi was growth-oriented and sensitive to environment while those outside the natural reserve was declining type and was less susceptible to the environmental impact.Taking all the results of the study showed that:key protected wild plant resources were relatively abundant in Wanning City, but due to the influence of human activity, the living spaces of key protected wild plants were smaller and smaller and aggregation degrees of populations were more and more obvious. But in recent years, under the conduct of related protection policy, nature reserves were established in Wanning City, and the key protected wild plants had recovered from different degree, and some part of the population presented a growth trend.