| Zhoushan island group lie southern to the Yangze river mouth and east sea area in hangzhouwan bay, 29°32′-31°04′N in latitude, 121°31′-123°25′E in Longitude. The island group is composed of 1390 individual islands, which cover a area of 1439.8 square km. These islands are dorminated by those blow 250m in altitude. The peak is 544.5m high, which is named Duizhi mount in Taohua island.The Huangyangjian ranked second in height, with a latitute of 503.6m. It lies in Zhoushan island.The main islands include Zhoushan island, Liuheng island, Jintang island, Zhujiajian island, Qushan island, Taohua island and Sijiao island ect. Dinghai district and Putuo district lie in the southwest regoin of Zhoushan, which are near to the mainland. These districts are comparetively high in altitute, with large amount of huge islands densely distributed.Cities of Daishan and Shengsi lie in the northeast part of Zhoushan, which are far from the mainland. These cities are comparetively low in altitute, with low islands scattered.The whole regoin belongs to northern edege of middle subtropical moosoon climatic area, with profound sea influences.The annual mean teperature ranges from 15.6℃to 16.6℃, with 4784℃to 5120.8℃accumulitive temperature(above 10℃), 251 day to 303 day nonefrost period, 927mm to 1620.2mm annual precipatation,1208.7mm to 1446.2mm mean evaporation in the whole year round, 0.91 to 1.73 average drought and wetness index.Soils on hillous areas are dormanated by red earth and Skeletol soils. Soils on little islands and on the facing-sea slops of huge islands are salt saturated red earth or morderate Skeletol soils. Coastal solonchaks distribute along both side of water mark of islands. In hill slopes and sandy land in front of valleys, soils belong to windy sand soil.The sea island vegetation lies in Castanopsis eyrei (Champ.)Tutch and Schima superba Gardn. et Champ. forest district of Zhejiang Fujian hillous area of northern part of mid subtropical ever green broad leaf forest belt.Because there exists a drought and wetness gradient from southern part to northern part of the sea island group, vegetation types, as restrained by the drought and wetness gradient, appear in turn Dinghai-Putuo ever green broad leaf forest, Daishan-Changtu mixed forest of ever green broad leaf trees and dicidous broad leaf trees, Qushan-Sijiao dicidous broad leaf forests.Zhoushan sea islands persue an unique resource of wild Fruiter species, which have a speciel importance in sea island biodiversity conservation. Based on the tramendous documentation in and outside Zhejiang, this paper studied and analysised the overall wild Fruiter resources in Zhoushan regoin, through field investagations carried out mainly in Zhoushan island, Daishan island, Liuheng island, Jintang island, Zhujiajian island, Qushan island, Taohua island, Sijiao island and Putuo island.The investagation covered an area of 93302.49 square km. From three different levels of species, ecosystems and distributions, the study, for the first time, sysmatically analysised biodiversity of wild fruit recources on Zhoushan islands. The main conclusions are as follows:1. Studies on wild Fruiters in Zhoushan was still blank. This study gave an overall and sysmatic report of wild Fruiter species in Zhoushan. There are 60 species blonging to 31 genus and 18 familia. Among these species, Rosaceae is the dormanating, with 16 species, belongs to 7 genus, which occupying a proportion of 22.6 percent of total genus and 26.7 percent of total species respectively. 3 family have species belonging to over 2 genus, these are Moraceae containing 4 genus, Fagaceae containing 4 genus and Rutaceae containing 2 genus. Those 4 familia as Rosaceae, Moraceae, Rutaceae and Fagaceae have 33species of 17genus,occupying a percentage of 22.2% of total famila, 54.8% of total genus and 55.0% of total species, which shows an important position in species compositon of wild Fruiters in Zhoushan sea islands.2. Some wild Fruiters have large amount of resoureces. There exist wild types or near family species of cultived Fruiters, and some species uniquely distribute on these sea islands or along coastal areas. Even some of the wild Fruiters have been widely implied with large exploitation potential.3. Besides richness in species, wild Fruiter species are special, whose distribution related with ecoenviorment indexes such as geography,climat etc. The species distribution pattern is southern regoin have more species than northern part, western regoin have more species than eastern part, mountainous regoins have more species than plain areas. As to administritive area, Putuo district in southern regoin have the largest number of 54 species, covering 90.0% fruit eppriciative species. Dinghai ranks second with 52 species, occupying 86.7%. Daishan city have 27 speices, which occupy 86.7% of total species.Shengsi city have 21 wild Fruiter species, which occupy the lowest 45.0%. This indicates that with a gradient of reduction in precipatation and increase in evaporation from south to north of Zhoushan island group, the life habitats get more and more sever for wild Fruiter species, as a result, species reveals an obvious reduction tendency from south to north. This phenomena concides well with the distributive rules of wild vascular plants in Zhoushan sea islands.4.Through investagaion in such different site types as stone based coastals, sandy coastals, alluvial coastals, hillous slpoes and around houses(road side at county entrance), we studied the distributive catergaries of wild Fruiter species. By doing this, not only can we tell the ecotype diversity of wild Fruiters, but also choose suitable and adaptive species for various purposes and diverse site.5. Attentions should be paid to the decreasing distribution, lose of areas, reduction of species of wild Fruiter species, as they are profoundly affected by hunman ecomomic activities, even some of then are threnghtened to extinct. Based on the detailed analysis of the resource status, biological characters, fruit periods, exploitation value and distribution of 60 wild Fruiter species, this study proposed advice and polices on resources pretection and sustainable utilization of wild Fruiters in Zhoushan sea islands (1) to pretect the native ecoenviorment, which the local vegetation depends on, (2) to strenthen the work on wild Fruiter resoures collection and conservation, (3) to standardize the wild resoure selection and seedling management, and (4) to hilight the study on resoure breeding, culitvation and utilization for apropriat and comprehensive expoitation of the wild Fruiter resource in Zhoushan sea islands.
|
PDF Full Text Request