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The Red-eared turle is one of the top 100 endangered invasive species. It is native to America, where the research focuses on these aspect of morphology, physiology and reproduction biology. In invasive places, invasive reports, biology information and potential harm were recommended. Along with an experiment about the competition of Red-eared turtles and native turtles were conducted. However, its habitat and feeding habits in original places and habitat, feeding habits, dispersal and propagation biology in invasive places haven’t been reported yet. From November 2008 to March 2011, we conducted a wide survey, observe in the field, anatomize, radio telemetry and plot survey to study the distribution, population, feeding habits, home range, microhabitat utilization of Red-eared turtle. The main results are as follows:Distribution range and Population density: The distribution and population of Red-eared Turtle in 22 rivers, 6 reservoirs, 8 lakes, 3 aquafarms, 21 markets, 6 temples, 18 cities and towns, 105 villages in Hainan Island were conducted through references review and field survey during November 2008 to December 2010. We found out that there were Red-eared turtle distribution in one little reservoir; 3 artificial lake and 10 rivers which were Nandu River, Wanquan River, Hongcheng Lake and so on. 12 cities and towns that where distributing Red-eared turtle which were Haikou, Qionghai and so on. We found 46 Red-eared turtle in all the surveyed water areas with meeting method.The linear density was 2.08 /km in Nandu river, 1.14 /km in Wangquan river, 2.4 /km in Hongcheng Lake, 1/km in Jinniuling artificial lake, 1 /km in Eastern lake. We caught 16 Red-eared turle by using cage traps method . The density was 0.0021/trap*day in N1 plot, 0.0032/trap*day in N2 plot, 0.0089/trap*day in N2 plot in Nandu river, and 0/trap*day in W1 plot, 0/trap*day in W2 plot, 0.0400/trap*day in W3 plot in Wangquan river. 102 Red-eared turle were caught in the habitates they like by catching directly. The number of Red-eared turle were significantly greater than native fresh water turtle.The distribution character of Red-eared turle were found by us,①they distribute in the water areas near the center of cities, and it begins to disperse to the water areas surrounding.②they like he calm water which abundant in food.③they can live in the half salt water.Feeding habits: Anatomise, observe method and dejecta analysis were conducted in feeding habits researches. The results of research on 76 Red-eared turtle showed that, there are 25 species which have been identified, and they are belong to 14 orders 18 families. Fishes(Unidentify) and seashells are in the main source of food for T. scripta elegans, e.g. Melaniodes tuberculata and Brotia swinhoei and so on. And the next is shrimps, e.g. Macrobrachium hainanense, and rats, crabs, birds, the lowest is batrachia and saurian. In plants, Pontederiaceae, Amaranthaceae, Gramineae are the most common foods, e.g. Eichhornia crassipes and Alternanthera philoxeroides and so on, next is Araceae, Moraceae, and Commelinaceae, e.g. Pistia stratiotes and Commelina communis and so on, the lowest is Convolvuloideae, Lemnaceae, and Euphorbiaceae. There was no significantly difference in frequency of feeding animal or plant food between male and female, young and adults.But there was significantly difference in weight ratio of feeding plant food. The female turtle feeding more plant food than male. There was very significantly difference in frequency and weight ratio of feeding between animal and plant food of male, female, young, adults and whole turtle.Red-eared turtle feeding more animal than plant, so it preference feeding animal food. The species which feeded by Chinese strip-necked turtle also were feeded by Red-eared turtle.Home range: 20 Red-eared turtle and Chinese strip-necked turtle were radio-tracked in Wangquan river during 20 July 2010 to 3 March 2011. 865 effective locuses were acquired, and home range were calculated by Ranges6. The results of radio telemetry showed that, the home range of Red-eared turtle is 14.21±7.88 ha(95%FK,N=8, 0.62-63.95 ha), and the core area is 1.61±0.75 ha(50%FK,N=8, 0.18-6.62 ha). Its line home range is 726.54±183.83m(N=8, 168.28-1802.91m)compared with Chinese strip-necked turtle’s home rang is 0.52±0.37(95%FK,N=2, 0.15-0.89 ha), and the core area is 0.15±0.10(50%FK,N=9, 0.05-0.25ha), and the line home range is 225.90±156.99(N=2, 68.91-382.89m). The home range, core home range, line home range and otherness of range of Red-eared turtle are all larger than that of Chinese strip-necked turtle. The home range of Red-eared turtle is center assembled and lap over with Chinese strip-necked turtle’s home range.Microhabitat use : The use of winter microhabitat was studied by systematic sampling in Red-eared turtle home range. The result of Microhabitat use study is that, species of aquatic animals, speed of flow water, water deep, canopy density, place of Bask in shell, aquatic animal biomass concealment, aquatic plants density and aquatic plants height are important for Red-eared turtle to choice the microhabitat. There are 11 Microhabitat factors are chosen by Red-eared turtle: speed of flow water, water deep, distance from bank, concealment, place of Bask in shell, species of aquatic plants, aquatic plants density, aquatic plants height, species of aquatic animals, aquatic animal density and aquatic animal biomass. Speed of flow water, water deep, distance from bank, concealment, place of Bask in shell, species of aquatic plants and aquatic plants density are differently chosen by Red-eared turtle in its home range. The habitat which Red-eared turtle prefer are abundant in aquatic animals and plants, high concealment, place of Bask in shell, still water or subcritical flow, and shallow water. The result of these study in Hainan island is that Red-eared turtle certainly will negatively affect biodiversity and threaten the local freshwater turtles in the habitat range which it lived in. Because a large number of Red-eared turtles widely distributed in field, lived in the same habitat with Chinese strip-necked turtle, it can eat many kinds of food both in Vegetation and animality and have strong ability to move and adapt.The main reason of Red-eared turtles widely distributed in field is they are released by people, so its distribution is degree related with human population intensive. Many people known about the Red-eared turle but known less about its harmful effects on the environment. So it is necessary to enhance the awareness of general publics to prevent from releasing this species into the wild, and continue to further study its invasive mechanism to provide scientific basis for legislation and management.
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