Study On Distribution Pattern And Population Characteristics Of Wild Dipterocarpaceae Plants In Hainan Province

Dipterocarpaceae is on behalf of families in the rainforest of Asia, becoming characterization of families in the tropical rainforests of Asia. Hainan is located in the southernmost area of China and it belongs to a classic tropical monsoon climate. Rainforest is the most complex ecosystems, so it has a very rich plant resources. Dipterocarpaceae plants are important in the tropical lowland rainforest of Hainan, and they are used to play an important role in indicating and regulating the whole ecosystem of Hainan. In recent years, the plants’living environment was protected better because of the establishment and expansion in Hainan natural reserve, but the wild plants, especially rare and endangered plants’living environment, was still under serious threat in non-nature reserves. The main reason was human interference. The impact was so serious that it undermine the growth environment of plants and hinder the development of the population. In order to investigate the current status of the protection of the ecological environment in the whole Hainan Island and some problems, this paper took Dipterocarpaceaeplant as the research target. We used"sampling method" to complete the field survey data so that we could understand the distribution of Dipterocarpaceaeplant resources in Hainan, then we analyzed comparatively the spatial distribution patterns and population characteristics of Dipterocarpaceaeplant populations in different habitats of non-nature reserves and nature reserves through the "spatial distribution" and "size structure division," "life table", "survival curve", "population dynamics quantify" and other methods. The specific results of the analysis were as follows:(1)Compared with environment in the non-nature reserve, the Dipterocarpaceae plants had more distribution points and larger number.Their altitudinal gradients distributed broader in the nature reserve so that the plants could grow better. This result showed that environment in the nature reserve could conducive to the growth of the population of Dipterocarpaceaeplants. Because the Hopea exalata population had been found only in the nature reserve, its population distribution is narrow. This special circumstances needed further study. The Vatica mangachapoi population could survey to 113 points and its frequency was 0.496 in the nature reserve, while in the non-nature reserve the Vatica mangachapoi population could survey to 51 points and its frequency was 0.584. This result showed that the Vatica mangachapoi population distributed wide in Hainan province and the population was relatively large. The Hopea hainanensis population could survey to 27 points and its frequency was 0.259 in the non-nature reserve, while in the non-nature reserve the Hopea hainanensis population could survey to 3 points and its frequency was 0.333.It showed that the Hopea hainanensis population was already in critically endangered.(2)No matter in non-nature reserve or in nature reserve, the Vatica mangachapoi and Hopea exalata population were clumped. This supported the conclusion that endangered plants presented cluster distribution basically. By analyzing the dynamic change of distribution pattern of the Dipterocarpaceaepopulation from different age classes, the population showed a trend of proliferation with the increas of age classes, which was inevitable process for the population to complete self-renewing in adapting to the environment. Compared with the condition in the non-nature reserve, the Vatica mangachapoi and Hopea hainanensis population started to performe uniform distribution in a larger age class. This showed that the efforts on the protection of population were stronger in the nature reserve and the self-renewal ability of population was stronger.(3)Although the Vatica mangachapoi, Hopea hainanensis and Hopea exalata population had a greater difference in the distribution area, Population size, endangered and the reason why they were not the same, the research from size structure, static life table and survival curve of plant populations indicated that the Vatica mangachapoi population was close to DeeveyⅡ type, while the Hopea hainanensis and Hopea exalata population was close to DeeveyⅢ type. From the method of quantitating population to make forward to analyze comparatively the structure of population, the results showed that although the population under two habitats are growth-oriented, but compared with the population of non-contrast nature reserve, the population of Dipterocarpaceaein nature reserves tended to be more stable.To sum up the results above, by analyzing comparatively the distribution and Population characteristics of Dipterocarpaceaeplant population in non-nature reserves and nature reserves, the growth and self-renewal cases of Dipterocarpaceaeplant population were better than the conditions in non-natural reserves. It described that the establishment of nature reserves could create a more powerful environment for the survival of plants to ensure succession and development of plant populations. But the situation about the wild plants which was in danger of extinctionis was still not optimistic, we needed to strengthen protection efforts about wild and rare plants and improve protection measures.