The Ecological Adaptability Of Trachemys Scripta Elegans In Brackish Water Of Nandu River, Hainan Island, China

The Red ear turtle（Trachemys scripta elegans）has been recognized as one of the100world’s most dangerous alien species. The current researches about Trachemysscripta elegans were all conducted at the fresh water areas. It is the first time to studythe ecology invade mechanism of Trachemys scripta elegans, and to get the Homerange, Microhabitatuse, Reproductive, Feeding habits ect, to carry out the ecologyand reveal the ecological adaptability in the brackish water. The data shownTrachemys scripta elegans can adapt to brackish water, that is the basic theory for thesolution for its invasion. Finally we known how to judge the danger bring byTrachemys scripta elegans, and how to control them. This experiment are includefollow parts:Homerange: The home range of the invasive Trachemys scripta elegans wastracked by acoustic and code radio receiving technology in the periods of September2012to November2013in brackish water(5.3‰～14.6‰) of Nandu River, HainanIsland, China. The home range and home range core of each individual wascalculated by minimum convex polygon and home range core domain method. Thehome range of turtles was3.83hm2±0.76hm2,the home range core was0.47hm2±0.21hm2.In breeding season, especially the male turtles, the home range andhome range core were significantly larger than those in non-breedingseason(P=0.032，P=0.030).In addition, the home range and home range core of maleturtles in breeding, were significantly larger than those of females(P=0.016，P=0.027).But, there were on significant difference between genders innon-breeding(P=0.561，P=0.625).Microhabitatuse: Using radio telemetry and tracking method of coil and followmicrobial application method to study and compare Trachemys scripta elegans’ fieldsmicrobial application. The result indicated that Trachemys scripta elegans hasselectivity for below6ecological factories: the depth of river, the distance from bank,the distance of disturbance, the flow of water, the crown density, the hidden degreesand the density of algae. Trachemys scripta elegans prefer to live in the shallow waterthat with moderate crown density(26.73%), high hidden degrees(50.17%), fullalgae(56.93%) and close to the bank(7.61m).Reproductive: Using Radio Telemetry and Coils to test12gravids Trachemys scripta elegans. During the study I got5egg nests from4different gravids, finally Igot55eggs and hatched15eggs successfully. The average of the hatch time andhatch temperature is62.25d±5.06d and27.65℃±0.57℃. The main tay eggs time isbetween11:00to15:00, there were around11±2.24eggs（n=5，8-14eggs）in eachnests. According to analysis the different ecological facories from the nests andquadrats, I found the significate difference onvegetation density(P=0.036), hetght ofvegetation(P=0.021), vegetation coverage(P=0.007),vegetation type(P=0.004) andsoil hardenss(P=0.000). All the data are indicate Trachemys scripta elegans wouldmore prefer to select medium crown density, medium vegetation coverage and soilhardness smaller sites as the nest.Feeding habits: Combine Anatomy, Stomach clean and Faeces3ways togetherto analysis the Feeding habits, the results shown that fish and algae is the highfrequency food for Trachemys scripta elegans, such as Tilapia, Periophthalmuscantonensis, Asparagus schoberioides, Cladophora etc. Red ear tortoise male andfemale, between a young for plant animal feeding frequency and weight than thedifference was not significant. into whole, red-eared turtle feeding weight than thesignificant difference of animals and plants(female P=0.023，male P=0.026，adultP=0.033，young P=0.019，total P=0.027), no significant difference than feedingfrequency(female P=0.235，male P=0.192，adult P=0.263，young P=0.312，totalP=0.286), with the increase of salinity, animal food feeding frequency ratio andweight ratio drops, plant rose.All the data from this research shown that red ear turtles can normal feeding,activities and breeding in brackish water environment. So Trachemys scripta eleganscan adapt to the brackish water environment and has the ability of invasion tobrackish water ecosystem, at the same time invasion of range will be increased andbring the danger to the ecosystem.