科创中国

在生态系统中,时滞对种群稳定性的影响一直是研究的重点内容之一.考虑了一类具有时滞的三种群食物链模型,利用微分不等式得到了种群的有界性;利用Matlab软件下的Simulink平台,对种群模型进行了数值仿真,得到了不同参数情况下的相空间轨迹,通过分岔图说明时滞对种群模型稳定性的影响.

在种群的增长率满足广义logistic方程的情况下,建立了在污染环境中一类新的单种群模型,给出了该模型中种群一致持续生存和灭绝的充分条件.这里建立的模型是He和Wang[Appl.Math.Modell.31(2007)2227-2238]中模型的改进.

Behavioral?research?has?long?had?an?important?role?in?the?conservation?of?terns?(Ayes:?Stemidae).?Habitat?management?and?restoration?of?breeding?colony?sites?depends?on?knowledge?of?the?cues?used?to?select?colony?and?nest?sites.?For?example,?conspecific?attraction?with?playback?and?decoys?is?commonly?used?to?bring?terns?to?suitable?colony?sites?and?habitat?modification?is?often?used?to?increase?the?availability?of?suitable?nest?sites.?Tern?colonies?are?interconnected?by?dispersal,?and?a?metapopulation?approach?is?needed?for?effective?management.?Population?dynamics?are?therefore?affected?by?behaviors?that?influence?the?frequency?of?movement?among?colony?sites:?site?fidelity,?natal?and?breeding?dispersal,?and?group?adherence.?The?monogamous?breeding?system?of?terns?should?keep?effective?population?size?similar?to?census?population?size,?but?variation?in?sex?ratios?(likely?resulting?from?sex?differences?in?behavior)?and?in?parental?quality?can?result?in?a?smaller?than?expected?effective?population?size.?In?addition?to?the?behavior?of?terns,?knowledge?of?the?behavior?of?predators?on?terns?contributes?to?management?plans,?because?predator?behavior?can?sometimes?be?manipulated?and?predation?is?often?performed?by?only?a?few?specialized?individuals.?Other?examples?of?links?between?tern?behavior?and?conservation?are?also?briefly?reviewed,?such?as?behavioral?toxicology?research?and?studies?of?behavioral?responses?to?human?disturbance?and?manmade?structures.?More?work?is?needed?on?the?behavior?of?migratory?terns?at?staging?sites,?stopover?sites?and?wintering?grounds,?and?on?the?behavior?of?less?well-studied?species?and?species?in?less?well-studied?geographic?regions?[Current?Zoology?60?(4):?500-514,?2014].

通过对系统进行细致的分析,得到一类具反馈控制和分布时滞的单种群微分系统持久性的充分条件.

为探讨吡虫啉对绿盲蝽种群数量的控制作用,2011-2012年连续两年采用种子包衣、颗粒剂穴施和灌根处理棉花,并结合种植绿豆诱集带的方式,研究其对棉田绿盲蝽种群动态的影响.在吡虫啉有效成分用量为1 500 g/hm^2时,棉花颗粒剂穴施+绿豆诱集带颗粒剂穴施、灌根和颗粒剂穴施3种处理,对棉田绿盲蝽种群数量控制作用较好,自棉花苗期至8月中旬花铃期百株绿盲蝽数量分别为12、15、17、8、19头,均低于为害经济阈值,控制有效期接近110 d;在吡虫啉有效成分用量为900 g/hm^2时的棉花颗粒剂穴施、灌根处理以及吡虫啉有效成分用量为675 g/hm^2的棉花种子包衣+绿豆诱集带种子包衣处理,对棉田绿盲蝽种群数量控制作用次之,控制期在100 d左右.单一棉花种子包衣处理控制效果低于上述处理,持效接近90 d.各处理对棉叶受害指数减退率的影响与其对绿盲蝽种群数量的控制结果基本一致,表明棉田吡虫啉颗粒剂穴施及液体制剂灌根施药是控制绿盲蝽为害的有效施药手段.

为了解中哈边境阿拉山口口岸地区蚊虫种群本底构成及生态习性,采用帐诱、挥网、灯诱采集蚊虫,进行形态学分类鉴定.2012与2013两年共采集成蚊16 317只、经随机抽样鉴定3 370只,隶属2科5属11种.2013年比2012年增加了2种,比历史资料记录的增加了5种,其中凶小库蚊占蚊虫总数的46.0%,为当地优势种.其生境季节变化从3月开始活动,5月达到高峰,8月为次高峰,至11月活动消失.调查结果显示应重视对优势蚊种的防控及携带病原的研究,识别外来物种的入侵、蚊媒疾病的监控提供了基础资料.

Studying movements is essential for shedding light on a number of issues related to avian biology: behavioral aspects such as foraging, migratory routes and strategies, navigation and orientation mechanisms; ecological aspects such as metapopulation dynamics, insular biogeography, seed dispersal, disease spread; conservation biology such as the effects of habitat fragmentation, identification of key areas deserving protection, effects of climate change. Despite these relevant issues, the topic of "Movement ecology" on its own has only been highlighted recently (Nathan et al., 2008);although, the investigation of animal movements has always been one of the most fascinating topics for any zoologist and often is also quite a difficult task.

文章研究一个具有脉冲与随机扰动的周期单种群扩散模型.通过构建合适的Lyapunov函数及利用脉冲微分方程比较定理与随机微分方程比较定理,获得种群灭绝和平均持续生存的条件.进而我们确定系统解的均值上界条件.

为了快速求解大规模优化问题,基于集合种群理论构造出了可全局收敛的生物地理学优化算法.在该算法中,每个斑块对应着优化问题的一个试探解;采用正交拉丁方原理构造出了斑块的适宜度特征变量初始化算法,实现了对搜索空间的均衡分散性和整齐可比性覆盖;将局域种群的跳转、混融和静止行为以及斑块的突变和选择现象用于构造斑块的适宜度特征向量演变策略,以便使得斑块的适宜度指数要么保持原状不变,要么向好的方向转移,从而确保了整个算法的全局收敛性;在斑块演变过程中,斑块从一种状态转移到另一种状态实现了对优化问题最优解的搜索.应用可归约随机矩阵的稳定性条件证明了本算法具有全局收敛性.测试结果表明本算法是高效的.