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《Limnologica》2014
The red swamp crayfish (Procambarus clarkii) is a freshwater invasive species which has become a worldwide problem. Recent work on ectozoochory of freshwater macrocrustacean species indicated that there might be a possibility of transport of recently-hatched crayfish by birds. In this context, we applied a new set of methods to quantify the probability of transport of recently-hatched crayfish, namely with moving animal vectors. First, we tested the desiccation resistance of crayfish and the capacity of crayfish to cling to mallard's feet, depending on the standing time of the feet. We also determined the ability of recently-hatched crayfish to cling to an artificially moving freshly dead mallard (Anas platyrhynchos) and finally, we determined the time required for the death of 50% and 90% of the individuals of recently-hatched crayfish under conditions similar to those of mallard flight.Recently-hatched crayfish were able to survive up to 225 min out of water, withstanding longer at a lower temperature and therefore transport does not seem to be limited by desiccation survival. The duration of the standing period of duck's feet positively affected the probability of transport of crayfish. Recently-hatched crayfish were able to cling to a moving duck and the probability of clinging was significantly affected by the water depth, being lower at greater depths. Moreover, when transported on a freshly dead duck under flight simulation conditions the time required for the death of 50% and 90% of the individuals were 2 min 14 s and 4 min 53 s, respectively. These flight durations correspond to transport distances of 2.8 km and 6.1 km, respectively, which is enough for transport to another aquatic system. The results demonstrate that passive transport of recently hatched P. clarkii by actively moving waterbirds is possible, and therefore it will likely enhance the local process of invasion. 相似文献
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内蒙古桃-阿海子的生境演替与水鸟群落的兴衰 总被引：4，自引：2，他引：2
桃力庙-阿拉善湾海子是内蒙古西部鄂尔多斯高原上一个水面曾为10 km2的荒漠咸水湖泊,因其在20世纪90年代承载了遗鸥最大繁殖群,于2002年被认定为全球第1148号国际重要湿地。随后,干旱少雨加之严重的人为干扰使桃-阿海子趋于干涸,遗鸥繁殖群于2004年放弃该地点而迁居他地,2005年当地水鸟群落彻底消失。数年后,桃-阿海子干涸湖底发育起碱蓬群落。自2011年蓑羽鹤在其间营巢繁殖,且数量逐年增多,并出现蓑羽鹤非繁殖群在此停歇与栖居。在鄂尔多斯高原东部已干涸的湖泊中,桃-阿海子是唯一一处在其湖底碱蓬群落发育后进而成为大型鸟类繁殖与栖息生境的地点,它将以何种方式演替值得关注。 相似文献
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以4种食块茎鸟类———白鹤(Grus leucogeranus)、白枕鹤(Grus vipio)、鸿雁(Anser cygnoides)、小天鹅(Cygnus columbianus)为研究对象,分析越冬候鸟种群数量与鄱阳湖保护区内湖泊水位变化的关系.2003 2007年越冬季节,采用直接计数法调查鸟类的种群数量,通过非参数回归分析鸟类种群数量与水位之间的关系.结果表明,虽然4种食块茎鸟类的种群数量最高值分布在不同水位,但峰值水位差异较小,且种群数量与水位关系的总体趋势呈现一致性.随着保护区内湖泊水位的下降,鸟类种群数量呈现先增长后减少的倒V字形趋势.在水位由16.0 m降至14.8 m(吴淞高程)的过程中,鸟类种群数量随着湖泊水位下降逐步增加达到最高峰;在水位由14.8 m降至13.5 m的过程中,鸟类种群数量随着水位下降而减少.当鄱阳湖水位处于14.5~15.5 m之间时,食块茎鸟类的种群数量较高,其种群数量最高点出现在水位14.8 m左右.2003 2005年3个年度鸟类种群数量与水位的关系相似,呈现出先增多后减少的单峰趋势,峰值水位均位于14.75~14.90 m之间,2006和2007年平均水位升高,鸟类种群数量分布的峰值水位也高于前3年,峰值水位出现在15.25 m附近.由于受到良好保护,大湖池和沙湖鸟类种群数量与水位的关系稳定,而梅西湖未呈现出有规律的变化趋势.研究表明在本研究区域中,水位在14.5~15.5 m之间4种食块茎鸟类的种群数量较高,该研究结果对鄱阳湖国家级自然保护区水位管控具有指导意义. 相似文献
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