【作者】 刘丹；

【导师】 史海涛；

【作者基本信息】 海南师范大学 ， 动物学， 2011， 硕士

【摘要】 红耳龟(Trachemys scripta elegans)已被列为世界最危险的100个外来入侵物种之一。在美国原产地对红耳龟的研究主要集中在其形态学、生理学和繁殖生物学等方面;在入侵地主要为入侵报道和已有生物学知识及潜在危害的介绍,以及人工实验条件下与当地龟种的竞争对比实验。未见该种原产地针对其栖息地选择、食性方面进行的研究报道,也没有入侵地关于其栖息地选择、食性、扩散和繁殖生态学等与入侵成功密切相关的研究报道。2008年11月至2011年3月,我们采用走访调查、野外调查、解剖、无线电遥测和样方调查相结合的方法,对红耳龟在海南岛的分布状况、种群数量﹑食性、活动家域、微生境利用等进行了研究。主要研究结果如下:分布范围和种群密度调查:2008年11月到2010年12月期间,采用走访和野外调查等方法对红耳龟在海南岛22条河流、6个水库、8个湖泊、3个养殖场、21个市场、6所寺庙的分布做了调查,共涉及18个市县和105个村庄。发现红耳龟在南渡江、万泉河、红城湖等共10条河流、1个小型水库、3个人工湖泊有分布,遍及海口、琼海等12个市县。采用遇见法发现红耳龟46只,遇见线密度南渡江为2.08只/km、万泉河为1.14只/km、洪城湖为2.4只/km、金牛岭湖为1只/km、东湖1只/km;采用笼捕法共笼捕到红耳龟16只,努力密度南渡江样区N1为0.0021只/笼捕日、N2为0.0032只/笼捕日、N3为0.0089只/笼捕日,万泉河样区W1为0只/笼捕日、W2为0只/笼捕日、W3为0.0400只/笼捕日;采用直接捕捉法在其偏好的生境共直接捕捉到红耳龟102只。其数量已经明显大于本地淡水龟。红耳龟在海南岛的分布特点为:①分布主要集中在城市中心附近的水域,并开始向其周边的水环境扩散;②栖息于平缓或静止的、食物较为丰富的水流中;③能在半咸水中生活。食性研究:食性研究采用解剖法、观察法、粪便分析法三种方法相结合。对76只红耳龟进行分析,结果显示红耳龟取食并已经鉴定的物种共25种,分别属于14目18科。统计结果显示,鱼类(未能鉴定到种)和贝类是红耳龟动物性食物中出现次数最高的食物,如瘤拟黑螺(Melaniodes tuberculata)、大川蜷(Brotia swinhoei)等,其次是虾类,即海南沼虾(Macrobrachium hainanense),接下来依次是鼠类、蟹类、鸟类,最低的是蛙类,蜥蜴类;植物性食物中,久雨花科(Pontederiaceae)、苋科(Amaranthaceae)、禾本科(Gramineae)是红耳龟取食次数较多的植物,如凤眼莲(Eichhornia crassipes)、空心莲子草(Alternanthera philoxeroides)等,其次是天南星科(Araceae)、桑科(Moraceae)、鸭跖草科(Commelinaceae),如大薸(Pistia stratiotes)、鸭趾草(Commelina communis)等,最低的是旋花科(Convolvulaceae)、浮萍科(Lemnaceae)、大戟科(Euphorbiaceae)。红耳龟雄雌、成幼间动植物取食频次上差异不显著,在取食重量比上仅雌雄间对植物性食物取食差异显著,雌性取食植物性食物多于雄性。其雌、雄、成、幼及整体对动、植物性食物的取食在频次和重量比上差异极显著,取食动物性食物频次、重量比均大于植物性食物,红耳龟偏爱于动物性食物。红耳龟与中华条颈龟在对物种的取食上存在重叠。家域面积:2010年7月20日到2010年3月3日期间,在万泉河主要研究区对20只红耳龟7只中华条颈龟进行了遥测跟踪,共获得865个有效位点,利用Ranges6软件计算其家域的面积。遥测结果显示红耳龟家域面积的大小为14.21±7.88 ha(95%FK,N=8, 0.62-63.95 ha),核心区面积大小是1.61±0.75 ha( 50%FK,N=8, 0.18-6.62 ha ),活动线家域是726.54±183.83m ( N=8, 168.28-1802.91m )。与之对比的中华条颈龟家域面积的大小为0.52±0.37(95%FK,N=2, 0.15-0.89 ha),核心区面积大小是0.15±0.10(50%FK,N=9, 0.05-0.25ha),活动线家域是225.90±156.99(N=2, 68.91 -382.89m)。红耳龟家域面积、核心家域面积、线家域面积及差异性均大于中华条颈龟。红耳龟活动家域有明显的中心聚集,且与中华条颈龟的活动家域重叠。生境选择:采用系统抽样法,选择了78个对照样方,40个实验样方,大样方为5m×5m,小样方为1m×1m,在红耳龟家域内对其冬季微生境的利用开展了调查。微生境利用研究结果表明,水生动物种数、水面流速、水深、郁闭度、晒壳场所、水生动物生物量、隐蔽度和水生植物密度、水生植物高度对红耳龟冬季微生境利用有重要影响。红耳龟对水面流速、水深、距岸距离、隐蔽度、晒壳场所、水生植物种数、水生植物密度、水生动物种数、水生动物的密度,水生动物的生物量等11个微生境因子的利用具有选择性,并且在其活动家域内对水面流速、水深、距岸距离、隐蔽度、晒壳场所、水生植物种数、水生植物密度等7个生态因子中的不同等级具有选择性。红耳龟偏爱于近岸的水生动植物资源丰富、隐蔽度高,有晒壳场所、静水或者水流缓慢的浅水环境。综合本次研究的结果可知,红耳龟在海南岛野外分布广泛、数量多、食性杂、取食种类多、活动范围大、适应能力强、与中华条颈龟生活环境相同,势必影响其同生境范围的生物多样性,威胁本地淡水龟的生存。其分布与人口密集程度相关,导致其野外大量分布的最主要的原因就是人为放生。民众对红耳龟有一定的了解,但程度不高,需加强宣传教育,提高对外来物种的防范意识,从根本切断红耳龟入侵源头。同时需继续深入开展红耳龟入侵机制研究,为立法管理提供科学依据。更多还原

【Abstract】 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.更多还原