The pitfalls of pitfalls: a comparison of pitfall trap catches and absolute density estimates of epigeal invertebrate predators in Arable Land

In an agroecosystem, catches of epigeal invertebrate predators obtained by pitfall traps were compared to absolute population densities estimated by ground photoeclectors in two different habitats, a field and an adjacent set-aside land. In general, abundance of Carabidae and Lycosidae were overestimated by pitfalls, while Staphylinidae and Linyphiidae were underestimated, and beetle larvae showed no obvious trend. The overestimation of Carabidae and Lycosidae by pitfalls had its maximum in spring and summer. Numbers collected by pitfalls did represent actual population densities better in the field than in the set-aside. This is probably caused by the higher vegetation diversity and complexity of the set-aside land which additionally influenced the catches. Pitfalls recovered higher numbers of animals and species, and species composition differed significantly between pitfalls and photoeclectors, in the field as well as in the set-aside. Body size seemed to be the main factor in determining the catch, the relatively larger species being more frequently caught by pitfall traps. In sum, the relationship between pitfall trap catches and actual population densities appeared to be either absent, weak or highly variable among taxa, habitat and time of the season. Thus numbers caught in pitfall traps cannot be considered as reliable indices of “real” abundance nor do they reflect the relative abundance within a given predator community correctly. Therefore, in most cases absolute density estimates should be preferred for the study of epigeal invertebrates in arable land. However, I suggest a combination of both pitfall traps and standardised area samples, because the two approaches possibly provide information of different qualities equally important for the evaluation of epigeal predator species, namely searching activity and population density.     

Variation in the abundance of invertebrate predators of the green spruce aphid Elatobium abietinum (Walker) (Homoptera: Aphididae) along an altitudinal transect

Green spruce aphid Elatobium abietinum (Walker) is a major defoliator of Sitka spruce (Picea sitchensis (Bong.) Carr.) in north-west Europe and other parts of the world that have a mild and wet maritime climate. Periods of cold weather during the winter currently limit E. abietinum populations and the amount of damage, but as mean winter temperatures rise in response to global climate change, overwinter survival of the aphid is likely to improve and the risk of severe and more widespread defoliation will increase. Populations of E. abietinum are also influenced by mortality caused by generalist invertebrate predators, although the extent to which predation might modify the response of E. abietinum to climate change is unclear. In this study, the response of generalist predators to changes in environmental conditions and potential increases in E. abietinum populations was evaluated by sampling invertebrate predators in the canopy of Sitka spruce along an altitudinal gradient from 310 m to 610 m above sea-level. Variation in predator abundance was related to local climate and aphid numbers. Population densities of E. abietinum differed widely between altitudes, and showed different patterns in different years, but mean densities over the 3-year study were highest at mid altitudes. In contrast, the majority of invertebrate predators (coccinellid and cantharid beetles, syrphid larvae, brown lacewings, spiders and harvestmen) were most abundant at low altitudes. Their abundance was not correlated with E. abietinum densities, but coincided with the more favourable climatic conditions at low altitudes and the availability of alternative prey. The association of low population densities of E. abietinum with greater general abundance of invertebrate predators at low altitudes, where higher temperatures would have been expected to promote higher aphid populations, suggests that above a certain temperature regime generalist predators have the capacity to prevent E. abietinum responding to further increases in environmental temperatures and eventually cause mean population densities to decline. Consequently, increases in the activity and abundance of natural enemies need to be considered when predicting how E. abietinum might respond to climate change.     

Analysing the Development of Small-Scale Forestry in Central and Eastern Europe

The current state and future prospects and challenges of small-scale forestry in Czech Republic, Hungary, Latvia, Lithuania, Poland, Romania, Slovakia, Slovenia and Ukraine are examined, and Q-methodology for stakeholder evaluation of forest sustainability and pro-market reforms is applied to an example from Ukraine. Small-scale forestry already provides multiple benefits to the countries in transition. However, these countries differ according to the maturity of the reforms, and the continuing process of transition is being delayed in some of them due to institutional weaknesses, e.g. the authority of government with insufficient involvement of rural communities in decision-making. The necessity of linking international and national sustainable forestry policy to management practices at a local level is especially evident in the countries where bottom-up small-scale adaptive forestry is only starting to catch up with the top-down sustainable forest management principles. The paper highlights the necessity of reconciliation of scientific and conventional knowledge for delivering sustainability objectives to small-scale forestry at a local level. It demonstrates that the social and economic pillars of sustainable forestry reform are of a particular importance for successful performance of small-scale forestry in the countries in transition, as is active involvement of stakeholders and local communities in decision-making and policy implementation.     

应用地理信息系统进行林木空间模拟分析

把地理信息系统方法引入林分空间结构研究中，对具体指定林分(硬阔叶林和白桦林)的林木空间分布进行模拟分析，获得它们分化度、混交度、聚集度、不同树种潜在生长空间，为研究该区域的森林生态系统修复和空间结构优化决策提供基本信息，为森林经营技术的发展提供有效的支持。     

福建九龙江口红树林生存现状分析

介绍了福建九龙江口红树林省级保护区的状况,提出该保护区目前新面临的高速运输工具造成的危害,过度的采挖、利用,与滩涂养殖的冲突,海洋的污染,外来生物的入侵,病虫害的危害,保护、管理的力度不够等问题。针对存在的问题提出了相应的解决对策和建议,认为解决问题的重点不仅仅在于保护红树林本身,更重要的还在于保护红树林的生境。红树林的保护和恢复必须靠全社会的认同和自觉行动。     

用红外光谱分析刨花蒸汽处理后成分的变化

用红外光谱法分析了云杉和白桦刨化蒸汽处埋后成分的变化。红外谱图不出了蒸汽处埋后刨花中的半纤维素和羟基比未处理的减少了,这是蒸汽处理改善刨花板尺寸稳定性的主要原因。红外谱图还示出了在同样的蒸汽处理条件下,白桦中半纤维素和羟基的减少程度大于云杉的减少程度,因此蒸汽处理后白桦刨花板尺寸稳定性的改善程度大于云杉刨花板的改善程度。     

浅析福清瑞岩山风景区规划设计

以福清瑞岩山风景区规划设计为例,分析探讨一种具有佛教特色,兼具地方文化特色的风景名胜区规划模式。     

Semi-forest coffee cultivation and the conservation of Ethiopian Afromontane rainforest fragments

Coffea arabica shrubs are indigenous to the understorey of the moist evergreen montane rainforest of Ethiopia. Semi-forest coffee is harvested from semi-wild plants in forest fragments where farmers thin the upper canopy and annually slash the undergrowth. This traditional method of coffee cultivation is a driver for preservation of indigenous forest cover, differing from other forms of agriculture and land use which tend to reduce forest cover. Because coffee farmers are primarily interested in optimizing coffee productivity, understanding how coffee yield is maximized is necessary to evaluate how, and to what extent, coffee production can be compatible with forest conservation.Abiotic variables and biotic variables of the canopy were recorded in 26 plots within 20 forest fragments managed as semi-forest coffee systems near Jimma, SW Ethiopia. In each plot, coffee shrub characteristics and coffee yield were recorded for four coffee shrubs. Cluster and indicator species analyses were used to differentiate plant communities of shade trees. A multilevel linear mixed model approach was then used to evaluate the effect of abiotic soil variables, shade tree plant community, canopy and stand variables, coffee density and coffee shrub size variables on coffee yield.Climax species of the rainforest were underrepresented in the canopy. There were three impoverished shade tree communities, which differed in tree species composition but did not exhibit significant differences in abiotic soil variables, and did not directly influence coffee yield. Coffee yield was primarily determined by coffee shrub branchiness and basal diameter. At the stand level a reduced crown closure increased coffee yield. Yield was highest for coffee shrubs in stands with crown closure less than median (49 ± 1%). All stands showed a reduced number of stems and a lower canopy compared to values reported for undisturbed moist evergreen montane rainforests.Traditional coffee cultivation is associated to low tree species diversity and simplified forest structure: few stems, low canopy height and low crown closure. Despite intensive human interference some of the climax species are still present and may escape local extinction if they are tolerated and allowed to regenerate. The restoration of healthy populations of climax species is critical to preserve the biodiversity, regeneration capacity, vitality and ecosystem functions of the Ethiopian coffee forests.     

"枫桥香榧"产量不稳定的原因分析和对策

通过对香榧产量不稳定的主要原因的分析,提出了建立甲级母树采穗圃、积(蓄)水仓、合理施肥、人工授粉、慎用植物生长剂等综合措施相配套的解决办法。     

Development and structure of the terminal layer in bamboo culms

In bamboo, the inner lining of the culm wall towards the lacuna is designated as a terminal layer. It develops during culm elongation by separation of pith cells. Subsequently, these cells collapse thus forming a skin-like structure to be attached to a transition layer of the culm wall. The transition layer between the skin-like structure and the ground tissue consists of a few cell rows of mostly radially and axially shortened cells with often thickened walls. Both the skin-like structure and the transition layer exhibit structural differences between species. These characteristics of the inner culm wall have significance for culm seasoning and especially for the diffusion treatment with preservatives.     

影响广东省石灰岩地区造林成活率的因素分析

石灰岩地区造林成活率低导致多年造林不见林 ,严重阻碍石灰岩地区绿化进程和经济发展。对石灰岩地区造林绿化现状调查 ,运用全面质量管理的理论和原理 ,采用PDCA循环工作法 ,分析导致石灰岩地区造林成活率低的各种因素 ,并提出对策措施。     

中（高）密度纤维板的近期市场分析与预测

干法中密度纤维板（以下简称ＭＤＦ）自６０年代中期问世以来，因其质地细密、结构均匀、力学性能好以及加工性能优异等特点，已经成为人造板家族中一个前景看好的重要板种。干法高密度硬质纤维板（以下简称ＨＤＦ）是近几年来随着复合地板市场及室内装修、装饰材料市场的快速增长而兴起的新板种，尤其是强化复合地板对薄板型ＨＤＦ的需求迅猛增长，使ＨＤＦ也成为人造板市场中前景很好的板种之一。１ 我国中密度纤维板的现状 我国对ＭＤＦ的研制工作起步于７０年代，并在８０年代初由黑龙江省林业设计研究院设计建成我国第一条ＭＤＦ生产线…     

Consequences of elevated temperature on the biology,predation, and competitiveness of two mirid predators in the rice ecosystem

Journal of Pest Science - Temperature is an important environmental factor in agriculture, affecting individual organisms and the entire farmland ecosystem. Global warming has become more tangible,...     

浅析福建省林产化工的现状和发展对策

通过对福建省林产化学工业的现状及存在问题进行分析，提出今后的发展对策     

Effect of pesticidal application during the early and late cotton season on the abundance of certain predators associated with cotton plants

The output of inspection resulted in the following common predators:Orius laevigatus Fieb.,Orius albidipennis Reut. (Hem., Anthocoridae);Chrysoperla carnea Steph. (Neur., Chrysopidae);Coccinella undecimpunctata L.,Scymnus syriacus Mars,Scymnus interruptus Goeze (Col., Coccinellidae). It was found that the 6 insect species appeared on the cotton plants during the last week of April or the first week of May. The population increased gradually during May and the first two weeks of June then decreased during the second two weeks of June and the first week of July.Orius spp. constitutes more than 50% of the inspected species. Data show that application of kelthane-S and methomyl against mites and aphids slightly reduced the population of these predators, percent reduction ranged between 10.6–17.9%. The same species previously inspected during the early season were found during the second half of the season, exceptC. undecimpunetata.

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Zusammenfassung Die Untersuchungen umfaßten folgende 6 Predatoren-Arten:Orius laevigatus Fieb.,O. albidipennis Reut. (Hem., Anthocoridae), —Chrysoperla carnea Steph. (Neur., Chrysopidae),—Coccinella undecimpunctata L.,Scymnus syriacus Marsh.,S. interruptus Goeze (Col., Coccinellidae). Es wurde festgestellt, daß diese 6 Insektenarten auf den Baumwolle-Pflanzen während der letzten April- oder ersten Mai-Woche erschienen. Ihre Populationen wuchsen während des Mai bis Mitte Juni und verringerten sich danach bis Ende Juni, Anfang Juli.Orius spp. machte mehr als 50% der Gesamt-Predatorenpopulation aus. Die Daten zeigen, daß die Anwendung von Kelthane-S und Methomyl gegen Milben und Blattläuse die Predatoren-Population um 10,6–17,9% reduzierte. Die gleichen Predatoren-Arten wie in der Frühsaison wurden auch in der Spätsaison festgestellt, mit Ausnahme vonC. undecimpunctata, der in der Spätsaison fehlte.

     

Isolation and growth of single genotype axenic cultures of Cronartium quercuum f. sp. fusiforme using hyphal fragments from multi-genotype stock colonies

A technique was developed to isolate and grow single genotype axenic cultures of Cronartium quercuum f. sp. fusiforme from individual hyphal fragments.Multi-genotype colonies established from multiple basidiospores served as stock material for single genotype establishments via hyphal fragments. multi-genotype colonies, subcultured fifteen days earlier, were minced via scalpel chopping and streaked on fresh medium. Single fragments of hyphae liberated from the minced inoculum were dispersed along the streak line, and those fragments widely separated from others were chosen as potential precursors for single genotype cultures. Three days after streaking, the widely separated fragments of hyphae were transferred along with a small amount of supporting agar to fresh medium. On fresh medium, single genotype cultures developed from individual hyphal fragments in 1.5 to 2 months. The addition of BSA (bovine serum albumin) to the growth medium greatly enhanced establishment of cultures. Of several media tested, HGYP with 0.4% or 1% BSA yielded superior establishment frequencies of 79% and 77%, respectively.This work represents a portion of a M.S. thesis submitted to North Carolina State University by the senior author.     

Potential for combined use of parasitoids and generalist predators for biological control of the key invasive tomato pest Tuta absoluta

The tomato leafminer Tuta absoluta (Meyrick) (Lepidoptera: Gelechiidae) has recently invaded Mediterranean countries and is a major pest in tomato crops. Trichogrammatid oophagous parasitoids have shown promising potential for controlling the pest before the yield decreases in the greenhouse. In protected tomato crops (greenhouse), mirid predators are commonly used for biological control of whiteflies and they also prey on T. absoluta. These predators do not attack Trichogramma adults but they may partially decrease the overall impact of parasitoids on T. absoluta if intraguild predation (IGP) occurs on parasitized eggs. Under laboratory conditions, we tested if the mirid predator Macrolophus pygmaeus shows preference between parasitized and unparasitized T. absoluta eggs. We also tested if the predator reduces the number of parasitized eggs on caged tomato plants (microcosms) and assessed the efficacy of natural enemies used alone or together in limiting T. absoluta populations. We found that IGP is inflicted on the parasitoid Trichogramma achaeae by M. pygmaeus and that the risk of IGP depends on the developmental stage of T. achaeae inside the egg because the larva is at risk mostly early in its development (when parasitized egg is still yellow). In addition, we observed that non-consumptive events, likely probing of the predator on parasitized eggs, may induce mortality in parasitoid offspring without actual feeding on parasitized eggs. However, both IGP and non-consumptive events decreased when the predator was not confined with parasitized eggs in small arenas. Despite negative effects of the predator to the parasitoid, results demonstrate that adding Trichogramma parasitoids may significantly increase the level of control of the pest over what could be attained when only the mirid predator M. pygmaeus is present on tomato. Implications of results are discussed regarding potential of these natural enemies for biological control of T. absoluta in greenhouse tomato crops.     

浅析国有林场可持续发展现状与对策

以浙江省开化县林场为例,通过分析当前国有林场存在的思想观念陈旧、素质偏低、继续教育滞后;生态公益林多、林种单一、经营机制不活;人员多负担重、干扰不断、基础设施落后;国家对林场投入长期不足;森林外延产业及森林绿色产品开发少;新兴产业发展慢,管理机制不活等方面的制约,对国有林场的可持续发展对策进行探讨。