辽宁地区迁飞黏虫种群动态与发生规律研究

为揭示沈阳和岫岩地区迁飞黏虫种群动态规律,本研究利用高空探照灯对迁入和迁出黏虫种群进行了监测,基于气象数据对2017-2018年沈阳和岫岩地区黏虫蛾发生时间、峰期和虫源性质进行了分析,旨在为黏虫灾害预防和异地测报提供参考。结果表明,辽宁地区黏虫蛾发生主要有2个峰期,一代蛾均为外地迁入种群,二代蛾羽化后随气流迁出。沈阳和岫岩两地均位于我国黏虫蛾南北往返迁飞路径之上。沈阳地区监测到黏虫蛾首发日期为5月11日,迁入期为5月中旬至6月上旬,峰期出现在5月底至6月上旬末;二代蛾迁出时期从7月上旬持续至8月上旬结束;三代蛾发生期不规整,8月中旬至9月中旬均有黏虫蛾上灯活动。岫岩地区监测的一代蛾发生期为5月底至6月上旬,迁出时期从7月中旬至8月中旬。降雨等气象活动是导致辽宁地区三代黏虫高发的重要原因,黏虫高发风险是东北北部地区种群南迁过境辽宁时相继迫降和本地外迁受阻种群共同繁殖的结果。

矮嵩草两种群结构水平的空间分布

用两项局部样方方差（ＴＴＬＱＶ）法和成对样方方差（ＰＱＶ）法研究了高寒矮嵩草草甸优势植物矮嵩草（Ｋｏｂｒｅｓｉａｈｕｍｉｌｉｓ）源株种群（ｇｅｎｅｔｐｏｐｕｌａｔｉｏｎ）和分株种群（ｒａｍｅｔｐｏｐｕｌａｔｉｏｎ）的空间分布格局。以方差均值比率（Ｓ￣２／Ｘ）的ｔ－检验和Ｘ￣２－检验对分布型进行检测。结果表明矮嵩草两种群结构水平的空间分布型完全不同，源株种群为随机分布，分株种群则为集聚分布。分株种群集聚分布格局的规模、强度和纹理在水平空间上与放牧强度的变化表现出一致性的关系。

包头市城区及周边地区景观生态规划研究

通过对包头市城区及周边地区景观现状分析,在找出景观生态存在问题基础上,以景观生态学的生态系统空间关系为研究重点,强调尺度的重要性与空间异质性,注重能量和养分空间流动,规划了包头市景观生态。围绕控制性组分进行设计,其中种群源设计了6块,廊道设计了四级,一级4条、二级5条、三级8条、四级22条、景观斑块与节点设计了76块和74个,设定了相应技术指标,满足生物种群的“持久性”和物种流动的“可达性”,实现城区生态系统与周边自然组分进行有效的物质和能量交流。

武汉市东湖新技术开发区景观生态规划研究

通过对武汉东湖新技术开发区景观生态环境的调查和分析 ,找出开发区景观生态环境存在的主要问题。并在此基础上 ,运用景观生态学的理论和方法 ,提出建立东湖新技术开发区景观生态规划的基本思路 :即在大尺度上将开发区整体上规划为光谷商贸中心组团、关东光电子信息产业园组团、关南生物医药园组团等七个组团 ;中小尺度上重点规划了自然山地种群源、南湖风景区及沿岸林带种群源、园林场种群源、汤逊湖种群源四个种群源 ,和三个等级的自然廊道。通过规划 ,达到对开发区的景观要素重新进行优化组合 ,形成多功能、多层次的绿化体系和完善的生态景观格局。

湖北省钟祥市粘虫发生规律研究

为了明确粘虫Mythimna separata(Walker)在湖北省钟祥市的发生规律,对小麦玉米轮作田粘虫成虫和幼虫种群的发生动态、粘虫雌蛾卵巢发育进度以及粘虫越冬虫量作了调查,分析了粘虫种群虫源性质。结果表明,钟祥市为1代粘虫多发区,其虫源为外地迁入的越冬代成虫,1代粘虫危害高峰期在4月中下旬,羽化盛期在5月中下旬,羽化后以迁出为主。第2代粘虫发生量很小,羽化后基本全部迁出;在田间未调查到第3代粘虫幼虫,本区发现的第3代成虫可能为由北方南迁的过境种群;第4代粘虫发生量也很小,羽化后全部迁出,不在本区繁殖危害。在田间未调查到准备越冬的粘虫。

湖北省钟祥市粘虫发生规律研究

为了明确粘虫Mythimna separata(Walker)在湖北省钟祥市的发生规律,对小麦玉米轮作田粘虫成虫和幼虫种群的发生动态、粘虫雌蛾卵巢发育进度以及粘虫越冬虫量作了调查,分析了粘虫种群虫源性质。结果表明,钟祥市为1代粘虫多发区,其虫源为外地迁入的越冬代成虫,1代粘虫危害高峰期在4月中下旬,羽化盛期在5月中下旬,羽化后以迁出为主。第2代粘虫发生量很小,羽化后基本全部迁出;在田间未调查到第3代粘虫幼虫,本区发现的第3代成虫可能为由北方南迁的过境种群;第4代粘虫发生量也很小,羽化后全部迁出,不在本区繁殖危害。在田间未调查到准备越冬的粘虫。

Kinetic Behaviors of Catalysis-Driven Growth of Three-Species Aggregates on Base of Exchange-Driven Aggregations

We propose a solvable aggregation model to mimic the evolution of population A, asset B, and the quantifiable resource C in a society. In this system, the population and asset aggregates themselves grow through selfexchanges with the rate kernels Kl（k,j） = K1kj and K2（h,j） = K2kj, respectively. The actions of the population and asset aggregations on the aggregation evolution of resource aggregates are described by the population-catalyzed monomer death of resource aggregates and asset-catalyzed monomer birth of resource aggregates with the rate kerne/s J1（k,j）=J1k and J2（k,j） = J2k, respectively. Meanwhile, the asset and resource aggregates conjunctly catalyze the monomer birth of population aggregates with the rate kernel I1 （k,i,j） = I1ki^μjη, and population and resource aggregates conjunctly catalyze the monomer birth of asset aggregates with the rate kernel /2（k, i, j） = I2ki^νj^η. The kinetic behaviors of species A, B, and C are investigated by means of the mean-field rate equation approach. The effects of the population-catalyzed death and asset-catalyzed birth on the evolution of resource aggregates based on the self-exchanges of population and asset appear in effective forms. The coefficients of the effective population-catalyzed death and the asset-catalyzed birth are expressed as J1e = J1/K1 and J2e= J2/K2, respectively. The aggregate size distribution of C species is found to be crucially dominated by the competition between the effective death and the effective birth. It satisfies the conventional scaling form, generalized scaling form, and modified scaling form in the cases of J1e〈J2e, J1e=J2e, and J1e〉J2e, respectively. Meanwhile, we also find the aggregate size distributions of populations and assets both fall into two distinct categories for different parameters μ,ν, and η： （i） When μ=ν=η=0 and μ=ν=η=1, the population and asset aggregates obey the generalized scaling forms; and （ii） When μ=ν=1,η=0, and μ=ν=η=1, the population and asset aggregates experience gelation transitions at finite times and the scaling forms break down.

Does landscape structure contribute to the long-term maintenance of generalized parasitism in cowbirds?

Unlike most brood parasites, several species of cowbird (Molothrus) are generalists that parasitize multiple host species across their range and within the same communities; likewise, there is little evidence that individuals within a population specialize on host species. This situation has variously been attributed to the recency of cowbird evolution (the 'evolutionary lag' hypothesis) or to hidden costs of rejection by hosts (the 'equilibrium' hypothesis). Both hypotheses have some support as cowbirds are indeed a relatively young clade compared with more specialized cuckoos and cowbirds are capable of sophisticated behaviors such as retaliation against rejection ('mafia' behaviors) that would select for acceptance of cowbird eggs. Nevertheless, many species in the Americas have evolved specialized defenses against cowbird parasitism, almost all of which live in more open habitats (e. g., grasslands, shrublands, riparian strips), which indicates that coevolutionary processes can operate in ways that select for host defenses in spite of cowbird counterdefenses. We propose that the structure of landscapes in North America may explain why forest-nesting birds lack defenses against parasitism and reinforce the long-term maintenance of generalized brood parasitism in cowbirds. Because cowbirds require open habitats in which to feed, they are rare or absent in large forest tracts, which dominate much of the forest cover of the Americas. These tracts act as 'source habitats' that produce surplus young that recolonize populations in smaller, fragmented forest patches in which rates of both cowbird parasitism and nest predation are very high ('sink' habitats). Evolution of antiparasite adaptations would be very slow in this situation because most hosts are produced in areas where there is little or no cowbird parasitism. In addition, the interplay of host breeding dispersal, source-sink metapopulation dynamics, and fragmented forest habitat could further deter the evolution of host defenses against parasitism. Therefore, as long as large forest tracts remain widespread in North America, most forest birds will likely continue to lack defenses against cowbird parasitism, guaranteeing a steady supply of na ve hosts in forest habitats, even in fragmented landscapes. This situation will, in turn, favor host generalist cowbirds that actively avoid more open habitats in favor of parasitizing forest bird communities. These forest communities may also act as source populations for cowbirds, which might pump surplus generalist cowbirds into more open habitats further slowing the coevolutionary process. As long as large forest tracts are a common part of the landscape, generalist parasitism may persist indefinitely.

COMPLEXITY ANALYSIS AND COMPUTATION OF THE OPTIMAL HARVESTING FOR ONE-SPECIES POPULATION RESOURCES

The exploitation of renewable resources creates many complex problems for culture, ecology and economics as well. Ascertaining the essentials behind the coraplex problems is very important, in this paper, we mainly study various complex relations appearing in the optimal exploitation process for renewable resources. First, we derive a sufficient condition on the existence of optimal harvesting policies for one-species population resources. Then we present every possible optimal harvesting pattern for such a modeh On the basis of this, we give a computing formula for estimating the optimal harvesting period, optimal transitional period, and optimal recruitment period. The main difference with respect to the previous works in literature is that our optimal harvesting policy is a piece-wise continuous function of time t, at the piecewise point to, which is called switching time. At the switching time we switch the harvesting rate from h to some transitional control u,, then to 0. Clearly this kind of harvesting policy is easier to carry out than those by others, provided that there exists a managing department which can highly supervise the resources.

Rufous-and-white wrens Thryophilus rufalbus do not exhibit a dear enemy effects towards conspecific or heterospecific competitors

Many territorial animals exhibit reduced aggression towards neighbours. Known as ＂the dear enemy effect＂, this phenomenon has been documented among conspecific animals across a wide range of animal taxa. In theory, the dear enemy ef- fect can also exist between individuals of different species, particularly when those species compete for shared resources. To date, a heterospecific dear enemy effects has only been documented in ants. In this study, we test for both a conspecific and heterospe- cific dear enemy effect in neotropical rufous-and-white wrens Thryophilus rufalbus. This species competes for resources with banded wrens Thryophilus pleurostictus, a closely related sympatric congener. We used acoustic playback to simulate ruf- ous-and-white wren and banded wren neighbours and non-neighbours at the edges of rufous-and-white wren territories. Ruf- ous-and-white wrens responded more strongly to signals from their own species, demonstrating that resident males discriminate between conspecific and heterospecific rivals. They did not, however, exhibit a conspecific dear enemy effect. Further, they did not exhibit a heterospecific dear enemy effect. This could be due to neighbours and non-neighbours posing similar levels of threat in this system, to the possibility that playback from the edges of the subjects＇ large territories did not simulate a threatening signal, or to other factors. Our study provides the first test of a heterospecific dear enemy effect in vertebrates, and presents a valuable experimental approach for testing for a heterospecific dear enemy effect in other animals [Current Zoology 61 （1）： 23-33, 2015].

OPTIMAL IMPULSIVE HARVESTING FOR FISH POPULATIONS

In this paper the management model a two-species fishery involving impulsesis investigated by using optimal impulsive control theorem. Optimal impulsive harvesting times andthe corresponding optimal harvesting population levels in different cases are obtained.

Resource enrichment combined with biomass removal maintains plant diversity and community stability in a long-term grazed grassland

Aims Long-term heavy grazing reduces plant diversity and ecosystem function by intensifying nitrogen(N)and water limitation.In contrast,the absence of biomass removal can cause species loss by elevating light competition and weakening community stability,which is exacerbated by N and water enrichment.Hence,how to maintain species diversity and community stability is still a huge challenge for sustainable management of worldwide grasslands.Methods We conducted a 4-year manipulated experiment in six long-term grazing blocks to explore combination of resource additions and biomass removal(increased water,N and light availability)on species richness and community stability in semiarid grasslands of Inner Mongolia,China.Important Findings In all blocks treated with the combination of resource additions and biomass removal,primary productivity increased and species richness and community stability were maintained over 4 years of experiment.At both species and plant functional group(PFG)levels,the aboveground biomass of treated plants remained temporally stable in treatments with the combination of N and/or water addition and biomass removal.The maintenance of species richness was primarily caused by the biomass removal,which could increase the amount of light exposure for grasses under resource enrichment.Both species asynchrony and stability of PFGs contributed to the high temporal stability observed in these communities.Our results indicate that management practices of combined resource enrichment with biomass removal,such as grazing or mowing,could not only enhance primary productivity but also maintain plant species diversity,species asynchrony and community stability.Furthermore,as overgrazing-induced degradation and resource enrichment-induced biodiversity loss continue to be major problems worldwide,our findings have important implications for adaptive management in semiarid grasslands and beyond.

Assessing Threats and Setting Conservation Priorities for Plant Species between Forest and Meadow Ecotone in Sanjiangyuan Nature Reserve, China

In order to understand the pattern and status of plant species in the forest-meadow ecotonein Sanjiangyuan Nature Reserve, this study was undertaken through expert consultation, literaturesurvey and fieldwork in various parts of the ecotone during 2002-2004. Based on 3 important systems,i.e. threatened status, genetic loss effect and use value, the list of threatened and prioritized plants wasestablished. In this paper, the threatened coefficient was defined as the criteria of category for threatenedplants, the conservation priorities coefficient summed by threatened coefficient, genetic coefficient anduse value coefficient was defined as the criteria of prioritized plants. In addition, 10 indicators toevaluate threatened grading and conservation priorities sequence were included in the 3 importantsystems. The weights of 3 systems and 10 indicators were given through expert consultation andanalytic hierarchy process. Ten indicators were given scores based on the subcriteria, respectively, andall the scores of the 3 systems were summed up for each species, then contrasted to the criteria ofthreatened grading and conservation priorities for plant species. The status of endangerment andconservation priorities of plant species were analyzed, and the results showed that the number ofendangered species was 2, vulnerable species 37, near threatened species 140, safe species 767; the firstconcern category had 4 species, the second concern category 18, the third concern category 150 and theleast concern category 774.