With the help of a continuation theorem based on Gaines and Mawhin＇s coincidence degree, several verifiable criteria are established for the global existence of positive periodic solutions of a class of non-autonomou...With the help of a continuation theorem based on Gaines and Mawhin＇s coincidence degree, several verifiable criteria are established for the global existence of positive periodic solutions of a class of non-autonomous single species population model with delays （both state-dependent delays and continuous delays） and feedback control. After that, by constructing a suitable Lyapunov functional, sufficient conditions which guarantee the existence of a unique globally asymptotic stable positive periodic solution of a kind of nonlinear feedback control ecosystem are obtained. Our results extend and improve the existing results, and have further applications in population dynamics.展开更多
生态位分化使时空资源利用重叠的物种实现共存,并且生态位研究在野生动物管理、种间关系和群落结构等方面有广泛应用和深远影响。放牧作为最主要的人为干扰之一,通过资源(食物、时间、空间等)竞争改变野生动物资源利用特征,甚至影响同...生态位分化使时空资源利用重叠的物种实现共存,并且生态位研究在野生动物管理、种间关系和群落结构等方面有广泛应用和深远影响。放牧作为最主要的人为干扰之一,通过资源(食物、时间、空间等)竞争改变野生动物资源利用特征,甚至影响同域分布物种的生存。华北豹(Panthera pardus japonesis)是我国特有的珍稀野生动物,而其野生猎物种群数量会因与家畜资源竞争而减少,甚至直接或间接地影响华北豹种群生存。因此掌握保护区内家畜与野生动物的空间、时间利用情况,得以评估野生动物的生存状态。于2018年10月-2019年5月,通过架设62台红外自动相机获取铁桥山自然保护区4种哺乳动物活动数据,采用双物种单季节模型(Two⁃species single season model)和核密度估计(kernel density estimation)分析华北豹与猎物及其家畜在圈养、散养期的空间互作关系和活动规律,并且通过重叠系数(Coefficient of overlap)计算两物种间日活动时间重叠。结果表明:(1)家畜放养期间,华北豹⁃狍,华北豹⁃野猪的空间回避作用均比无家畜存在时减弱,可能是时间重叠程度增大的补偿机制。华北豹⁃牛的空间回避作用最强。(2)华北豹⁃牛时空重叠程度不大,牛⁃狍时空重叠程度较大,牛⁃野猪空间上共存而时间重叠程度较小。(3)日活动节律的结果说明狍为昼行性,野猪为晨昏活动。因探测到华北豹的次数有限,故关于其的日活动节律仍待考究。研究表明,放牧将影响华北豹与猎物的时间、空间资源利用情况,并有可能导致人⁃豹冲突加剧。展开更多
基金supported by the National Natural Science Foundation of China under the Grant(10426010)the Foundation of Science and Technology of Fujian Province for Young Scholars(2004J0002)+3 种基金the Foundation of Fujian Education Bureau(JA04156)the National Natural Science Foundation of China under Grant 60373067the Natural Science Foundation of Jiangsu Province,China under Grants BK2003053Qing-Lan Engineering Project of Jiangsu Province,the Foundation of Southeast University,Nanjing,China under Grant XJ030714
文摘With the help of a continuation theorem based on Gaines and Mawhin＇s coincidence degree, several verifiable criteria are established for the global existence of positive periodic solutions of a class of non-autonomous single species population model with delays （both state-dependent delays and continuous delays） and feedback control. After that, by constructing a suitable Lyapunov functional, sufficient conditions which guarantee the existence of a unique globally asymptotic stable positive periodic solution of a kind of nonlinear feedback control ecosystem are obtained. Our results extend and improve the existing results, and have further applications in population dynamics.
基金This Work is Supported by the National Natural Sciences Foundation of People's Republic of China under Grant 10061004 and the Natural Sciences Foundation of Yunnan Province
文摘生态位分化使时空资源利用重叠的物种实现共存,并且生态位研究在野生动物管理、种间关系和群落结构等方面有广泛应用和深远影响。放牧作为最主要的人为干扰之一,通过资源(食物、时间、空间等)竞争改变野生动物资源利用特征,甚至影响同域分布物种的生存。华北豹(Panthera pardus japonesis)是我国特有的珍稀野生动物,而其野生猎物种群数量会因与家畜资源竞争而减少,甚至直接或间接地影响华北豹种群生存。因此掌握保护区内家畜与野生动物的空间、时间利用情况,得以评估野生动物的生存状态。于2018年10月-2019年5月,通过架设62台红外自动相机获取铁桥山自然保护区4种哺乳动物活动数据,采用双物种单季节模型(Two⁃species single season model)和核密度估计(kernel density estimation)分析华北豹与猎物及其家畜在圈养、散养期的空间互作关系和活动规律,并且通过重叠系数(Coefficient of overlap)计算两物种间日活动时间重叠。结果表明:(1)家畜放养期间,华北豹⁃狍,华北豹⁃野猪的空间回避作用均比无家畜存在时减弱,可能是时间重叠程度增大的补偿机制。华北豹⁃牛的空间回避作用最强。(2)华北豹⁃牛时空重叠程度不大,牛⁃狍时空重叠程度较大,牛⁃野猪空间上共存而时间重叠程度较小。(3)日活动节律的结果说明狍为昼行性,野猪为晨昏活动。因探测到华北豹的次数有限,故关于其的日活动节律仍待考究。研究表明,放牧将影响华北豹与猎物的时间、空间资源利用情况,并有可能导致人⁃豹冲突加剧。
