| An important part to the wild animal research is to get the accurately and timely,Analyze the factors of animals which lead to its habitat change in dynamicenvironment.3S (GIS\RS\GPS) technologe, was used to analyze the data obtainedfrom field surveys and satellite images can classify and visualize animals habitat, andmake multiple factor analysis to a certain category or some habitat factors in largerscales of time and space for more comprehensive, more accurate animal habitatconditions.Red-eared slider (Trachemys scripta elegans), is a common invasive species offreshwater turtle originating in the Mississippi Valley of Central-South United Statesof America. Red-eared slider nominated as among100of the "World’s Worst"invaders, and widely introduced to South America, Europe, Africa, Australia, Asia andother worldwide area, including the east and west coasts of the USA, and104distribution records has been found in China. Despite a large amount of researchrelated to taxonomy, population, behavior, food habit, and reproduction of red-earedslider has been done in the USA. Some intensive experimental carried out aboutinvasion ecology, focus on its invasive route, Distribution of invasion, food habitat,Competition and hybridization with native species etc in the area of invasion.Recently, Used the SDMs predicted the distribution of suitable habitats, and furtherpredicted potential distribution in large scale that had attracted much attention.In China, there is still limited study on Habitat Suitability analysis of invasivespecies, especially for those in large scale. Hence, this paper was used3S technologeto assess suitable habitat of red-eared slider turtle, and support by National naturalscience foundation of "Studies on the invasion ecology of the exotic red-eared sliderturtle (Trachemys scripta elegans)", and analyze suitable invasion habitat for theRed-eared slider turtle.Basing on1741locations from27individuals tracked, the ecological factors such as elevation, slope, aspect, cover type, distance to water and human disturbancedistance were collected in November2012-June2013. Analyzed the correlation ofecological factors by linear regression. Using Vanderploge and Scavia’s selectivityindex to assess red-eared slider turtle’s habitat selection for the different habitatparameters.3S technology was used to analyze the data obtained from field surveysand satellite images, and classifying remote sensing data of Landsat TM digital imagein2009by supervised classification. At the same time, analyzed space-time evolutionof habitat, landscape pattern and trend forecast of the habitat change. Besides that,The Markov model was used to predict the changes of habitat until2024. The resultsindicated.Habitat selection of red-ear slider turtle Red-eared slider turtle preferred to selectthe habitat with an altitude of0-15meters, the human disturbance distance to waterfrom200to400m, and artificial forest distance to water below100m.Land use in study area The study area were mainly composed of plantation covertype and secondly were dry land cover type, The river were throughout the study area,the large reservoir were relatively concentrated in east in Qionghai, the farmlandcover type mainly distributed around the waters and construction land, and theconstruction land were a lot of concentration distribution in central or eastern regionsof study area. Natural forest distribution in west in Qionghai, Intertidal zonedistributed in the coastal area of rivers, and grassland is more random and scattereddistribution in all of the study area. During the1999to2009, the plantation cover typearea were increasing most significantly, and the secondly were construction land, thenatural forests were decreasing most obviously, reduced3418.4hm2, and the secondlywere dry land.Analysis and prediction on Spatial-temporal Changes of red-eared Slider turtlehabitat During1999to2009, the suitable habitat for the red-eared slider turtle hadbeen increased. Until2009, Suitable habitat and less suitable habitat increased685.47hm2and4594.91hm2respectively, and the increasing rate were7.76%and42.79%, Unsuitable habitat decreased5280.37hm2and the decreasing rate was3.55%.Suitable habitat, less suitable habitat and unsuitable habitat were95.13km2,153.32km2and1432.58km2respectively, accounting for5.66%,9.12%and85.22%respectively of the total area, in2009. According Markov prediction model, the areaof suitable and less suitable habitat will be increasing to10106.38hm2and16672.51hm2respectively, and unsuitable habitat will be reducing to141324.66hm2in2024.Landscape pattern index of red-eared Slider turtle habitat According thelandscape pattern index of study area, the MPS (Mean patch size) value was markeddecreasing, the ED (Edge density), AWMSI (Area-weighted mean shape index) andAWMPFD (Area-weighted mean patch fractal dimension) value had been has beenthe weak trend of decrease, and the SHDI (Shannon’s diversity index) and SHEI(Shannon’s evenness index) value was decreasing from1999to2009. And also foundthat the landscape pattern index of red-eared slider turtle’s habitat, compared otherarea, had the smallest MPS, the most complex shape and larger edge length. It wasimplied that the suitable habitat of red-eared slider turtle had the biggest interferencefor human disturbance.Conclusions The suitable habitat was increased of red-ear slider turtle during the10years and keep on15years in future. This implied that red-ear slider turtle will spreadeasily and native turtle will survive difficultly. We considered that main factorsresulting in this habitat change was human activity. On the one hand, The constructionof tourist city was exacerbated interference of human activity, and led to land-usechange. Unfortunate, Human structural alterations of the environment often facilitateinvasion. On the other hand, More human activity means more chance for invasion ofalien species. The alien species invade pathway main by human activity, such as, trade,aquaculture and religious freeing.This activity easily make red-ear slider turtle invadethe area which cann’t arrive by themselves, and cause a greater threat for ecologicalsystem. Hence, How to manage and control the red-ear slider turtle is particularly critical in the next step. |
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