防护林阶段定向经营研究Ⅰ.理论基础

基于多年防护林经营研究与实践,在分析防护林经营目的的基础上,提出了防护林阶段定向经营理论基础.以防护林的防护成熟为核心,将防护林经营阶段划分为成熟前期, 即从栽植后形成相对稳定的幼林到初始防护成熟龄;防护成熟期,防护成熟状态持续的时期,即从初始防护成熟龄到终止防护成熟龄; 更新期,林木接近自然成熟开始更新直到更新结束并形成相对稳定的幼林.防护林经营的定向是指在任何经营阶段内,一切经营技术与措施都是为了使防护林向着成熟的状态发展,即防护成熟是防护林经营的方向,是最终目的.为尽量维持防护林的成熟状态并使防护效益不间断,针对发育正常与低质衰退的林分,在各个经营阶段内采取相应的系列经营管理与改造措施.     

防护林阶段定向经营研究Ⅱ.典型防护林种——农田防护林

以防护林阶段定向经营理论为基础,对典型防护林种———农田防护林的防护成熟、经营阶段、更新方式、方法进行了研究讨论;通过对东北地区农田防护林长期调查积累资料的分析,确定了乡土杨和杂交杨(Populus spp.)农田防护林的初始防护成熟龄和终止防护成熟龄分别为16～24年和自然成熟龄,第一代农田防护林的更新龄为32～36年.以树木径级离散度、防护成熟龄和更新龄为主要依据定量划分了杨树农田防护林的3个经营阶段,并重点讨论了不同更新方式下3个经营阶段的变化情况,给出了维持农田防护林成熟状态的疏透度调控技术及其相关的林木分级依据与标准.同时为实现定向经营的目标,提出了各个经营阶段内应采取的系列经营管理措施.     

防护林阶段定向经营研究Ⅱ. 典型防护林种--农田防护林

以防护林阶段定向经营理论为基础,对典型防护林种-农田防护林的防护成熟、经营阶段、更新方式、方法进行了研究讨论：通过对东北地区农田防护林长期调查积累资料的分析,确定了乡土杨和杂交杨（Populus spp.)农田防护林和初始防护成熟龄和终止防护成熟龄分别为16-24年和自然成熟龄,第一代农田防护要的更新龄为32-36年,以树木径级离散度,防护成熟龄和更新龄为主要依据定量划分了杨树农田防护林的3个经营阶段,并重点讨论了不同更新方式下3个经营阶段的变化情况,给出了维持农田防护林成熟状态的疏透度调控技术及其相关的林木分级依据与标准,同时为实现定向经营的目标,提出了各个经营阶段内应采取的系列经营管理措施。     

防护林防护成熟与干扰

防护成熟是经营防护林的核心问题.作者在回顾防护林防护成熟研究进展的基础上,指出以往关于防护林防护成熟的研究,往往把森林看作一个纯自然物品,这是个非常理想的状态;提出了在干扰几乎无处不在的当今社会,对防护林防护成熟的认识上应重视干扰因子的作用;并给出了防护林防护效益变化模式图,对防护成熟与干扰的关系进行了分析和讨论.     

基于林网体系尺度上的农田防护林持续经营模型I——模型的构建

在农田防护林可持续经营内涵与目标分析的基础上,提出农田防护林可持续经营的理想结构;以矩(方)形林网体系作为研究对象,分析经营尺度、更新能力、林带更新年龄、更新方式等林网体系时空结构状态要素,提出农田防护林可持续经营模型构建的基本条件;根据林网体系中林带环度与林带数量的关系,标定并量化网格中林带的空间位置和年龄结构分布,定义了需要更新林带之间的距离函数,来表征各林带之间的分散程度;根据更新林带在林网体系内时空分布的均匀性,构建了农田防护林可持续经营模型。     

东北地区农田防护林高效多功能经营的指标体系及标准研究

从单条林带和林网两个尺度出发,建立了农田防护林高效多功能经营的指标体系,并通过分析各个指标之间的机理关系,提出了9个主要评价指标,对于单条林带,用林带疏透度,有效防护距离,初始防护成熟龄,防护成熟期,林带产投比,更新方式等可作为度量林带经营状态的指标;对于林网体系,用林网带斑比,林网连接度,环度,林网优势度等可作为度量林网经营状态的指标;依据主要指标的数量化界定,提出了农田防护林高效多功能经营的标准,可进行综合评价,这些评价指标及其标准,在宏观上确定了主要林网体系的布局,在微观上确定了单条林带的结构,成为衡量是否可持续经营的依据,为其高效多功能经营提供了导向。     

干细胞定向分化的基础和临床应用研究

胚胎干细胞具有多向性分化的潜能,可以分化成为内、中、外三个胚层的所有细胞,存在于组织器官中的成体干细胞（包括心脏等的前体细胞）也能分化成为某些细胞,用来修复、补充体内受损、死亡的细胞.目前干细胞研究的重点是：干细胞未分化和多向性机制的基础研究;干细胞向特定细胞群体分化的调控和分化细胞的应用研究,而后者是连接基础研究和临床研究的必经之路.干细胞的基础和临床应用研究不但可以了解正常的胚胎发育过程,而且利用掌握的知识通过体外诱导或体内激活的方法针对性地治疗某些疾病.目前我们的研究集中在神经细胞（包括视网膜细胞和内耳前体细胞）、脂肪细胞和心肌细胞定向分化的分子机理,并通过疾病动物模型验证这些定向分化的细胞的功能.希望通过建立人胚胎干细胞以及成体干细胞向外胚层的特种神经元（包括前脑神经上皮细胞、GABA和胆碱能神经元、视觉细胞、听觉细胞、多巴胺能神经元）和中胚层的脂肪细胞、骨细胞以及心肌细胞定向分化的模型,继而采用蛋白质组学和基因组学最新技术分析这些建立的模型,研究相关因子通过哪条信号传导通路导致这些细胞的定向分化或者通过改变哪个目的基因的表达,或改变目的蛋白的修饰导致干细胞定向成神经细胞、脂肪细胞和心肌细胞;研究成年脑内源性干细胞定向诱导成这些功能性神经元的机理,并进行比较研究.用Lentivirus转染干细胞高表达、或用RNA干扰抑制上述研究得到的目的基因,在细胞模型和动物体内验证这些信号通路和目的基因在干细胞定向分化中的作用.     

微米木纤维定向重组细胞纤维含量的定量求解理论研究

本文采用人造板微观力学和木材细胞学理论,提出了一种利用木纤维细胞壁厚的数学求解方法,应用本文提出的理论,可以根据纤维、木质素、细胞直径和排列的程度,建立理想状态下微纤丝的含量和分布情况,为人造板力学运用数学手段深入到细胞结构研究的深度提供了一种新的理论和方法,并且可以为定量解释人造板力学规则细胞出现不同剖分方法后,材性与性能提高的理论原因提供定量解释的数学手段。     

大尺度陆地生态系统管理的理论基础及其应用研究的思考

大尺度陆地生态系统管理是解决当前全球资源环境挑战、应对气候变化、治理区域生态环境、实现社会经济可持续发展的重要技术途径,是全球自然资源和生态保护理论及应用研究的热点。本文采用对过去20年间的几个国际大型生态系统管理行动计划跟踪分析方法,从生态系统管理学科发展、理论基础及应用研究的视角,对生态系统管理概念及其应用问题进行了重新思考,具体内容包括以下3个方面: 首先,回顾了生态系统管理科学概念及应用实践的发展历程,讨论了概念的内涵及其再定义,归纳了生态系统管理社会实践及其对学科发展的贡献。其次,明确了生态系统管理研究的科技使命及基本任务,梳理了生态系统管理科学的科学体系及其主要研究领域,概括了生态系统管理科学的生态学基础理论及知识体系,明确了生态系统管理行动的关键环节、管理方案的基本要素与管理途径。最后,分析了生态系统管理科学研究及学科发展的新趋势,讨论了生态系统管理科学的重点研究空间尺度和对象系统,提出了全球生态系统管理的前沿科学问题,整合生态学研究思维及宏生态系统途径,以期为中国的生态系统管理科学研究及学科发展提供参考。     

OECD/PISA研究中科学素养的涵义及其理论基础

OECD／PISA是由经济合作及发展组织(Organization for Economic Co-operation and Development．以下简称OECD)策划的学生基础能力国际研究计划(Programme for International Student Assessment,以下简称PISA),是继TIMSS(第3次国际数学与科学测试项目)之后,全球范围进行的又一项大型学生学习质量比较研究项目。目的是评价15岁学生在完成义务教育之后,是否能够掌握未来生活所需的知识与技能。它是不同政府间的共同研究,是一项集体协作研究计划。     

沙地樟子松人工林营林技术研究进展

人工林能否实现可持续经营与其营林技术息息相关。中国造林与世界各地一样,纯林多．树种单调．发生的问题也相似。自20世纪90年代以来,沙地樟子松人工林出现了不同程度的衰退现象．但目前在我国北方干旱、半干旱风沙地区樟子松人工造林仍在大面积推广．因此,为实现樟子松人工林的可持续经营,总结并探讨樟子松人工林营林技术显得尤为重要。本文在广泛收集国内外有关樟子松研究的基础上,综述了近20年来有关樟子松在造林和经营方面的研究进展,主要包括造成樟子松沙地造林成活率和保存率低的原因、提高造林成活率的技术方法、种子的生产、密度管理、栽培模式以及问伐与更新等,提出了在沙地樟子松造林与经营研究中亟待解决的一些问题和建议．对今后樟子松沙地人工林衰退研究及经营实践具有参考价值。     

不同经营模式茶园土壤微生物熵对台风干扰的响应

台风干扰可能显著影响我国东南沿海山地茶园土壤有机碳稳定性和矿化过程,而土壤微生物熵（qMB）是指示土壤有机碳稳定性和矿化潜力的敏感指标。因此,研究不同经营模式茶园土壤微生物熵对台风干扰的响应,可为山地茶园土壤碳库管理提供重要科学依据。为此,以浙江省台州市天台县苍山顶传统化肥经营的纯茶园（M0）、林茶间作（M1）、茶园养鸡（M2）、施用微生物肥料的纯茶园（M3）四种经营模式茶园为研究对象,在2021年7月28日台风"烟花"（第6号台风）来临前一天（T1）、台风过境后一天（T2）和台风过境后7天（T3）,按照表层土壤（0-10 cm）和亚表层土壤（10-30 cm）采集四种经营模式的茶园土样,同步测定土壤有机碳（SOC）含量、微生物生物量碳（MBC）和可溶性有机碳（DOC）含量。结果表明：（1）台风干扰对M2和M3的土壤有机碳影响更显著,而且不同经营模式茶园中表层和亚表层的土壤有机碳含量对台风干扰的响应存在差异;（2）台风干扰对M2的土壤微生物熵影响更显著,对表层土壤的微生物熵影响更显著,说明台风干扰对M2土壤有机碳稳定性和矿化影响显著,M2的土壤微生物熵对台风干扰的响应显著;（3）台风干扰对M2的土壤微生物生物量碳影响最显著,对M0和M1的影响最弱,且不同经营模式茶园中不同土层的土壤微生物生物量碳对台风干扰的响应存在差异;（4）台风干扰对M0的土壤可溶性有机碳含量影响更显著,M1和M3次之,对M2的影响最弱。而且不同经营模式茶园中表层和亚表层土壤的可溶性有机碳含量对台风干扰的响应存在差异。综上,台风干扰会对不同经营模式茶园土壤微生物熵影响程度不同,说明台风干扰对不同经营模式茶园土壤有机碳稳定性具有不同程度的影响,其中M2的土壤有机碳是响应台风干扰最敏感的经营模式茶园。     

Reducing the impact of insect herbivory in eucalypt plantations through management of extrinsic influences on tree vigour

In this paper it is argued that concepts developed in ecologically derived insect–plant interaction models can contribute directly to the management of insect herbivory in eucalypt plantations. Common to most species of commercially planted eucalypt is their genetic potential for early rapid growth. Several plant defence theories predict that intrinsically fast growing plants are able to tolerate relatively high levels of herbivory. The risk of this strategy failing increases when plants are exposed to external stressful factors that reduce canopy growth and vigour. Results from a young Eucalyptus camaldulensis plantation stressed by moisture deficit and two young Eucalyptus dunnii plantations, stressed by flooding and weed competition, respectively, are summarized. In all three cases, the stress‐inducing agents reduced canopy growth rates and architecture so that the proportion of leaf tissue damaged by insects increased and the tree’s ability to tolerate this damage decreased. Therefore, alleviating tree stress through improved silvicultural practices or improved site selection techniques may indirectly reduce the impact of insect herbivory. In resource‐limiting environments, an alternative approach may be to plant eucalypt species that although slower growing, are predicted to have better defended foliage. Manipulation of these natural antiherbivore plant strategies are not exclusive of other management approaches, such as the need for routine surveillance of key pest insects or the genetic selection of natural insect resistance and selective chemical control techniques, but should be viewed as an overarching concept for plantation health.     

Leishmaniasis vector potential of Lutzomyia spp. in Colombian coffee plantations

Potential vectors of Leishmania braziliensis Vianna were assessed at four study sites in the mountainous Valle del Cauca, western Colombia, from March to June 1989. In an active focus of transmission at 1450 m altitude, a coffee plantation at Versalles, there were high densities of antropophilic phlebotomines: Lutzomyia columbiana (Ritorcelli & Van Ty) and Lu.townsendi (Ortiz), both in the verrucarum species group, and of Lu.pia (Fairchild & Hertig). At a comparable altitude in a forest reserve at Yotoco where leishmaniasis is unknown, Lu.pia was the prevalent species and Lu.townsendi was absent. In two localities at 1150 m altitude, there were plentiful Lu.lichyi (Floch & Abonnenc) plus both species in the verrucarum group, but Lu.pia was absent. One of these localities, a coffee plantation at Villa Hermosa where a leishmaniasis outbreak occurred in 1986, was compared with a leishmaniasis-free, partly wooded nature reserve at Mateguadua. No natural infections of Leishmania were found in a total of 1896 wild-caught female phlebotomines belonging to at least seven species. It remains unclear why Leishmaniasis transmission is associated with coffee plantations in this part of Colombia. Laboratory-bred Lu.lichyi females were invariably autogenous, and blood-seeking females of this species were always parous. Parity rates in wild-caught females of other species were 55% Lu.pia, 24% Lu.columbiana and 14% Lu.townsendi. Female Lutzomyia infected artificially with Le.braziliensis promastigotes developed peripylarian infections. Higher proportions of Lu.townsendi (96%) and Lu.columbiana (78%) became infected but these species developed lower rates of stomodaeal infections (P less than 0.1) than Lu.lichyi (37%) or Lu.pia (44%).(ABSTRACT TRUNCATED AT 250 WORDS)     

杉木火力楠混交林养分归还与生产力

通过对野外试验和室内测试数据的整理分析．比较研究了杉木火力楠混交林和 杉木纯林养分归还、吸收等生态过程的特征以及生产力结果表明混交促进了养分归还过 程．可提高土壤肥力和系统生产力．１５年生混交林技和叶凋落物分别是纯林的２倍和３ 倍,其中容易分解的火力楠凋落物占 ６４％．混交林通过凋落物分解所归还的养分是纯林 的 ２～ ３倍．相当年凋落量 ６５． ９％的混交林根系年死亡量是纯林的 ２倍,在整个系统养分 归还中占有很大的份额．混交林土壤全 Ｎ、 ＮＨ＋４－Ｎ和有效 Ｋ分别比纯林提高 ６４． ３％。 ８２． ３ ％和 ６３． １％．与此同时土壤孔隙组成和水分过程也大为改善．混交林生产力较纯林 提高５２．７％．混交林５种大量元素的归还／吸收比率是纯林的２倍,表明混交林养分循环 效率较高,较少的人为维持可以保持较高的生产力水平．     

元谋干热河谷不同人工林中鞘翅目甲虫多样性比较

在元谋干热河谷采用网扫法调查了云南松林、桉树林、新银合欢林、桉树＋新银合欢林、印楝林及多树种混交的人工林鞘翅目昆虫多样性。结果表明,鞘翅目甲虫标本925号,计71种,分属18个科,其中叶甲科种类最丰富,象甲科数量最丰富。人工林鞘翅目昆虫群落物种丰富度在7～23,Shannon—Wiener多样性指数在1．249～2．562,昆虫多样性总体较低。各样地鞘翅目群落之间为不相似水平。云南松林鞘翅目昆虫群落物种丰富度、Shannon—Wiener指数、Simpson指数及Pielou指数分别为20、2．562、0．104和0．855,其多样性最高,多树种混交林较高,印楝林较低,而桉树林、新银合欢林、桉树＋新银合欢林多样性极低。多树种混交的恢复对昆虫多样性提高有显著促进作用。     

Impact of management intensity on non-vascular epiphyte diversity in cacao plantations in western Ecuador

A first study on the biodiversity of non-vascular epiphytes in cacao (Theobroma cacao L.) plantations in western Ecuador yielded 112 species (51 bryophytes, 61 lichens). Epiphyte assemblages of cacao plantations resembled those of tropical rain forests but species richness was usually lower and individual species were found at lower heights on the trunks. The vast majority of the species are widespread neotropical or pantropical species; one species, Spruceanthus theobromae (Spruce) Gradst., is endemic to cacao plantations of western Ecuador. Differences in management intensity, by manual removal of epiphytes from tree trunks (limpia), had a significant impact on epiphyte species diversity. Total species richness was significantly reduced in plantations with high management intensity, due mainly to the decreased diversity of lichens and liverworts; moss diversity was not affected by management regime. Total percentage cover of bryophytes was highest in plantations with low management intensity, while lichen cover was greatest in plantations with high management intensity. Crustose lichens and smooth mats growing closely appressed to the substrate were little affected by the limpia and their growth may have been promoted when larger-sized species were removed, by reducing competition. Cacao plantations with low and moderate management intensity serve as an important substitute habitat for ecological specialists (sun epiphytes, shade epiphytes) of the rain forest and are of considerable significance for their conservation.     

Natural oak forest vs. ancient pine plantations: lizard microhabitat use may explain the effects of ancient reforestations on distribution and conservation of Iberian lizards

Natural vegetation in Europe appears nowadays deeply modified by human activities. In the Guadarrama Mountains (Central Spain), ancient reforestations with Scots pines, Pinus sylvestris, replaced original deciduous pyrenean oak, Quercus pyrenaica, forests (since the Roman period). However, the effect of reforestations on fauna remains little known, especially in reptiles. We described patterns of microhabitat selection in several species of Lacertid lizards, and analyzed whether the modification of the original vegetation affected distribution and population densities of lizards. The species of lacertid lizards found in oak forests (Psammodromus algirus, Lacerta lepida and Podarcis hispanica) were different to those of in pine plantations (Podarcis muralis and Podarcis hispanica). Lizards did not use habitat at random and this could explain differences in species found in both forests, which differed in some microhabitat structure characteristics. Most lizards selected microhabitats with rocky outcrops, with low cover of trees, and close to refuges. These microhabitat preferences also explained abundance of lizards in transects. From the perspective of conservation and management of lizards, pine plantations seem not to contribute too much to the diversity of lizard species because species typical from oak forests were lost. This study has implications for pine reforestation management, because allowing the recolonization by understory␣oaks, and leaving some open areas, without trees but with dense shrubs and rocks inside reforestations would contributed to maintain lizard populations.