白头叶猴采食植物的再研究

2006年使用了较先进的录像设备,结合单筒望远镜对白头叶猴进行了全天候的跟踪观察和录像,使我们有可能更准确地仔细鉴定白头叶猴采食的植物及采食部位,也为动物生态的研究提供一个可重复验证的方法。经统计分析发现:白头叶猴属热带分布的灵长类动物,全以植物的各部分器官为食;被采食的植物大多数为热带分布的物种,是当地植被重要的建群种或优势种;在白头叶猴采食的物种中,有一部分是人类使用的药用植物;其中落叶成分和喜钙植物都较多;初步认为白头叶猴对不同的植物其喜食程度有明显不同。     

白头叶猴采食植物初析

白头叶猴是仅分布于热带北缘广西西南部岩溶区的猴类,属国家一级保护动物。对白头叶猴采食的植物进行初步分析表明,其食性较复杂(共采食138种植物),以常绿和落叶的乔木、灌木和藤本植物为主;以桑科、大戟科、蝶形花科、鼠李科、苏木科、葡萄科和萝摩科等被采食的种类较多。多属森林的中下层成分,其中有100种为民间常用的中草药,32种为常见动物(牛、羊、猪、马)的饲料植物,未发现其采食裸子植物、禾本科植物和珍稀植物。初步认为白头叶猴的采食不会对当地植被造成大的威胁,但对其攀登栖息所造成的影响尚未研究。     

皇甫川流域治理区与原生植被区植物多样性比较研究

在皇甫川流域,分别选择原生植被区、人工恢复治理区和退化未治理区3个样区,对其物种组成特征、优势种重要值、物种多样性特征等进行了对比分析.结果表明:人工恢复治理区经过20余年的小流域治理,其植被的区系组成、优势种组成和物种丰富度已接近原生植被区,生态优势度则显著高于退化未治理区和原生植被区,但其生活型谱、水分生态类型组成特征与未治理区相似而与原生植被区差异较大,均匀度和信息多样性指数则低于退化未治理区和原生植被区.文中还对流域治理过程中植被重建措施及生物多样性恢复等问题进行了初步探讨.     

海南次生植被与其土壤性质的关系探讨

在野外调查和室内分析的基础上,对海南岛热带次生植被及其土壤性质变化关系开展了研究。结果表明,热带森林在不同程度的人为干扰下,形成了多样化的次生植被类型,在调查区域内植物群落类型多达36种。其中,次生密林有10种类型;次生疏林有4种;灌丛有11种,草地11种。结果还表明,不同植被类型的土壤肥力状况从大到小依次为次生林>灌丛>草地。植被性状、植被与土壤复杂关系主要体现在:(1)次生植被类型的物种组成特性间相关性较大;土壤各营养元素含量之间的相关性变化较大;(2)植物组成特征与土壤各营养元素含量之间的相关性系数普遍偏小。     

任楼矿区塌陷土地复垦规划与利用现状研究

露天煤矿排土场占用和破坏了大量土地资源,植被恢复是露天煤矿排土场生态恢复最常用,也是最有效的方法。关于排土场自然恢复植被群落特征的研究,对于指导排土场的生态恢复建设具有重要的理论价值与实际意义。以呼伦贝尔草原区伊敏露天煤矿排土场为研究对象,采用野外调查和统计分析相结合的方法,对排土场自然恢复过程中植物群落特征进行了研究。结果表明,研究区排土场共有植物21科64种,其中菊科、禾本科、豆科和藜科所占比例较大,为4科33属37种,占总种数的57.8%。随着自然恢复时间的增加,物种数由初期的6科8属8种增至后期21科43属48种;植被由耐干旱贫瘠的1年生草本蒺藜和猪毛菜向多年生草本大针茅、羊草和克氏针茅演替;物种多样性指数、物种丰富度指数和Pielou均匀度指数均呈增加趋势,且与恢复年限呈显著正相关,Alatalo均匀度指数与恢复年限呈显著负相关。群落物种组成逐渐接近原生植物群落,物种多样性高于原生植物群落,但分布均匀程度低,达到稳定状态还需更长的时间。     

甘肃环县天然草地植被近40年演变的研究

环县地处陇东黄土高原北部,面积9 326 km2,其天然植被为森林草原与荒漠草原过渡地带.通过对40年前后天然草地植被的比较研究,得出40年来在自然和人类共同作用下,天然草地植被演变的结果是:天然分布的原生植被基本被天然次生植被所替代,植被组成更趋于简单化,天然生长的乔木和灌木群系消失,地带性顶极植被类型短花针茅、长芒草和大针茅群系消失,小面积分布的部分群系消失,各群系中次优势种发生了改变,植被的生态学特征发生变化,生态功能显著降低,天然草地植被严重退化,造成这一结果的主要原因是人类的垦荒、砍伐和过度放牧,而非自然因素的作用.     

山东省济莱高速公路生态护坡植被恢复过程分析

以山东省中部半干旱地区济青南线济南至莱芜高速公路部分石质边坡客土喷播生态防护试验工程为研究对象,通过应用样方调查法对试验研究区内的路堑岩石边坡原生和次生生态恢复植被进行了随机调查.结果表明,客土喷播和植生带绿化等是实现开挖山体坡面的快速植被恢复的边坡生态防护措施,次生植被恢复演替进程比自然植被恢复明显加快.从植被种群的物种重要值、生态位宽度、生态位重叠等计测结果发现,在次生植被恢复过程中逐渐形成以紫花苜蓿、高羊茅、紫穗槐、多年生黑麦草、马棘等为主的重要值较高的草灌型植被,演替趋势为豆科草向豆禾草演替,多草型向草灌型演替,种间资源竞争不强证明边坡植被恢复1.5a时期的植被仍处于演替的初级阶段.     

工程堆积体上不同植被类型枯落物和土壤水文效应

为探讨工程堆积体不同植被类型的枯落物特征、枯落物持水及拦蓄能力、土壤物理性状和土壤涵水性能,采用室内浸水法和环刀法分别对工程堆积体植被与原生植被的枯落物及0—20 cm土层的持水能力进行研究。结果表明:(1)不同植被类型枯落物厚度及蓄积量均存在显著差异(P0.05),原生乔木林、乔木林、灌木林、草地枯落物厚度依次为3.76,2.89,2.67,1.23 cm,蓄积量分别为5.95,3.86,3.19,0.65 t/hm~2。枯落物未分解层厚度、蓄积量均大于半分解层。(2)各植被类型土壤容重与毛管孔隙度范围分别在1.19～1.25 g/cm~3和41.58%～46.13%,原生乔木林土壤容重小于乔木林,而土壤毛管孔隙度大于乔木林。堆积体各植被类型土壤毛管孔隙度大小依次为草地灌木林乔木林。(3)各植被类型土壤最大持水量及毛管持水量均存在显著差异(P0.05),土壤最大持水量与毛管持水量范围分别为44.31～46.23,34.07～37.98 g/cm~3,均呈现原生乔木林最高,乔木林最低。(4)枯落物持水量随时间呈对数关系,吸水速率随时间呈幂函数关系,其吸水速率在0.5 h最高,在4.0 h下降,12 h最大持水量达饱和,吸水速率接近于0。(5)原生乔木林枯落物最大持水率、有效拦蓄率均大于乔木林,工程堆积体各植被类型最大持水率及有效拦蓄率表现为草地灌木林乔木林。从堆积体枯落物和土壤持水能力角度来看,草灌混交这一搭配模式可以作为工程堆积体的先锋植被,用于在堆积体初期构建稳定群落生态结构。研究结果可为工程堆积体开展水土保持治理措施和植被恢复提供理论依据。     

干旱区荒漠植被动力学及恢复对策调控指标分析

干旱区贫瘠土壤和植被单一是立地质量的重要指标,在水平结构上表现为一种有、无植被及不同种群组成的镶嵌分布,镶嵌分布具有的不均匀性在尺度变换下具有不变性特征;立地质量决定了抵抗破坏力度和恢复力度均弱,因而原生植被破坏时残存的幼苗或幼树经长期恢复形成了顶级单优结构。这就为应用生态学最著名的种群模型来研究其动力学行为奠定了基础。对动力学模型中的控制参数利用多种调控因子的组合分析,定量化地进行了受控变化研究,通过深入调试各种调控因子的数值范围、最佳指标的数值域和危险指标的数值域后,可提供便于操作的具体数据范围。     

青藏高原三江源区不同恢复期高寒草甸土壤线虫群落演变

青藏高原三江源地区的高寒草甸面临着严峻的退化问题，人工建植是三江源地区退化草地的重要修复方式。为探究地下生物对草地人工恢复措施的响应，本研究比较了三江源地区高寒草甸不同恢复期人工草地(建植1、5和10 a)的土壤线虫群落变化。结果显示：与原生植被样地相比，所有恢复期样地的植物地下生物量降低，土壤容重、pH、全磷、全钾和硝态氮含量升高，表明人工草地系统的初级生产力和土壤特性尚未恢复到原生草地状态。不同恢复期样地中土壤线虫的均匀度和多样性指数均显著高于原生植被样地。此外，不同恢复期样地的线虫多度、代谢足迹以及成熟度指数均随恢复年限的增加而增加。相关性分析结果表明，土壤线虫多度与植物地下生物量、土壤有机质、全氮、全磷、矿质氮和速效氮含量显著正相关(P<0.05)，与土壤pH、全钾和容重显著负相关(P<0.05)。尽管三江源区退化草地的人工恢复措施尚未完全恢复牧草生产力至原生植被状态，但土壤生物结构及功能具有改善的趋势，显示该地区退化草地生态系统具有较强的恢复潜力。     

Potential impact of global climate change on forest distribution in Sri Lanka

The potential impact of climate change on forest distribution in Sri Lanka was evaluated. The Holdridge Life Zone Classification was used along with current climate and climate change scenarios derived from two general circulation models, the Geophysical Fluid Dynamics Laboratory model and the Canadian Climate Centre Model, at a 0.5° × 0.5° resolution. Current and future distributions of life zones were mapped with a Geographic Information System. These maps were then used to calculate the extent of the impact areas for the climate change scenarios. The current distribution pattern of forest vegetation includes tropical very dry forest (6%), tropical dry forest (56%), and tropical wet forest (38%). Results obtained using the Geophysical Fluid Dynamics Laboratory model show an increase in tropical dry forest (8%) and decrease in tropical wet forest (2%). The Canadian Climate Centre Model scenario predicted an increase in tropical very dry forest (5%) and tropical dry forest (7%), and a decrease in tropical wet forest (11 %). Both models predicted a northward shift of tropical wet forest into areas currently occupied by tropical dry forest. The application of general circulation models such as the Geophysical Fluid Dynamics Laboratory model and the Canadian Climate Centre Model, as well as the Holdridge Life Zone Classification, to estimate the effect of climate change on Sri Lankan forests in this paper indicates that these methods are suitable as a tool for such investigations in Sri Lanka.     

Modeling potential changes of forest area in Thailand under climate change

The forest cover of Thailand has been characterized according to the Holdridge Life Zone Classification, a model that correlates climatic features with vegetation distribution. Six Holdridge life zone types of forest cover are found in Thailand: subtropical dry forest, subtropical moist forest, subtropical wet forest, tropical dry forest, tropical moist forest, and tropical wet forest. Climate change scenarios were simulated by three general circulation models: two United Kingdom Meteorological Office models (the low and high resolution versions) and the Goddard Institute for Space Studies model. These scenarios were used to simulate the effects of future climate change on Thai forests. The ratios of precipitation and the absolute values of temperature changes were incorporated into a baseline climate scenario from the International Institute of Applied Systems Analysis. Under the climate change scenarios simulated by the three general circulation models, the subtropical dry forest could potentially disappear, and areas of tropical very dry forest would appear. In general, the area of subtropical life zone would decline from about 50% to 20%–12% of total cover, whereas the tropical life zone would expand its cover from 45% to 80%. All three general circulation model scenarios suggest that the tropical dry forest has the greatest potential to extend into the subtropical moist forest. This analysis suggests that global climate change would have a profound effect on the future distribution and health of Thai forests.     

Landscape change and the science of biodiversity conservation in tropical forests: A view from the temperate world

Using a largely temperate forest perspective, this article briefly reviews four often inter-related types of landscape change which can have significant impacts on tropical and temperate forest biodiversity: logging, fire, forest clearing, and plantation expansion. There are many important similarities but also key differences in the kinds of work conducted on these four kinds of landscape change in tropical and temperate forests. For example, direct studies of the effects of forest conversion on biodiversity are relatively rare in both tropical and temperate ecosystems. Temperate forest research differs from tropical research in terms of relative amount of single species work, long-term studies, and research at scales spanning multiple landscapes. There are key areas for cross-fertilization of research in tropical and temperate forest biomes. These include: (1) the ability of species to persist in post-disturbed forest landscapes, including those perturbed by past clearing, logging or wildfire, (2) the impacts of plantation establishment on biodiversity, (3) the effectiveness of altered silvicultural systems on forest structure, vegetation composition, and biota, and (4) inter-relationships between forest logging and fire-proneness. Cross-learning about the impacts of drivers of landscape change between tropical and temperate forests is fundamental for speeding the progress of conservation efforts in both broad kinds of environments. However, some opportunities for cross-learning have not been taken because temperate and tropical forest research has often sometimes been isolated from one another. Some approaches to tackle this problem are briefly outlined.     

Supply of tree-holes limits nest density of cavity-nesting birds in primary and logged subtropical Atlantic forest

Tree cavities are proposed to limit populations and structure communities of cavity-nesting birds. Although the greatest diversity of cavity-nesting birds is found in tropical and subtropical moist forests, little is known about how tropical logging affects the abundance of cavities or cavity-nesting birds. We compared the abundance of cavities and cavity nests between primary and selectively-logged subtropical moist Atlantic forest in Argentina, and conducted the first before-after controlled nest-box addition experiment to determine whether nest sites limit the breeding density of cavity-nesting birds in tropical or subtropical moist forest. Visual inspection of 86 cavities identified through ground-surveys revealed that only 19% were suitable for nesting birds, suggesting that cavity abundance may be overestimated in the literature on tropical forests. Suitable cavities were found in fewer than 1% of 1156 trees <60 cm dbh but 20% of 20 trees >100 cm dbh. Logged forest had half the basal area of primary forest, one third the density of large trees, nine times fewer cavities suitable for nesting birds, and 17 times fewer active nests. When we added nest boxes, nesting density increased on treatment plots but not on control plots in both logged and primary forest, suggesting that cavity supply can limit nest density even in relatively undisturbed forest. This is the first experiment to show how reduced cavity supply in logged tropical forest can limit breeding density of cavity-nesting birds. International initiatives such as forest certification should promote tropical timber management strategies that conserve large live cavity-bearing trees.     

Tolerance of frugivorous birds to habitat disturbance in a tropical cloud forest

In view of the continued decline in tropical forest cover around the globe, forest restoration has become a key tool in tropical rainforest conservation. One of the main - and least expensive - restoration strategies is natural forest regeneration. By aiding forest seed influx both into disturbed and undisturbed habitats, frugivorous birds facilitate forest regeneration. This study focuses on the tolerance of a frugivorous bird community to anthropogenic habitat disturbance within the broader context of natural forest regeneration with conservation purposes. It was carried out in the tropical cloud forest of Costa Rica’s Talamanca Mountains. Bird community response and tolerance to habitat disturbance was assessed by comparing bird presence and densities along a disturbance gradient, ranging from open pastures to closed mature forests. Birds were censused along nine transects applying the variable width line transect procedure. Forty relevant frugivorous bird species were observed during 102 h of survey time. Densities were calculated for 33 species; nine species responded negatively to increasing level of disturbance and nine others positively. Results indicate that large frugivores are generally moderately tolerant to intermediate, but intolerant to severe habitat disturbance, and that tolerance is often higher for medium and small frugivores. It appears that moderately disturbed habitats in tropical cloud forests are highly suitable for restoration through natural regeneration aided by frugivorous birds. Due to a lack of large forest seed dispersers, severely disturbed habitats appear less suitable.     

华南热带水土保持林的水文效应

本文从森林的截留、地表径流、地面侵蚀等方面,以窿缘桉纯林和由多树种组成的阔叶混交林为研究对象,分析了华南热带水土保持林的水文效应。观测和试验结果表明,无论是涵蓄水源或是防止土壤侵蚀,纯桉树林都不如混交林的效果显著。因此,华南热带水土保持林的方向应是发展混交林,改造纯桉树林。     

Conserve or convert? Pan-tropical modeling of REDD–bioenergy competition

The land competition between tropical bioenergy plantations and payments for forest carbon conservation (e.g., through an international scheme for Reduced emissions from deforestation and forest degradation, REDD+) is modeled using spatially explicit data on biofuel feedstock (oil palm and sugar cane) suitability and forest biomass carbon stocks. The results show that a price on the (avoided) carbon emissions from deforestation at the same level as those from fossil fuel use makes clearing for high yielding bioenergy crops unprofitable on about 60% of the tropical evergreen forest area. For the remaining 40% deforestation remains the most profitable option. Continued profitability of forest clearing is most pronounced for oil palm bioenergy systems in Latin America and Africa, with REDD+ making deforestation for sugar cane plantations unprofitable on 97% of evergreen forest land. Results are shown to be relatively robust to assumptions regarding potential yields and to the addition of a ‘biodiversity premium’ on land use change emissions. While REDD+ may play an important role in stemming biodiversity loss and reducing carbon emissions from tropical deforestation in the near future, in the longer run reliance on a system that values forests solely for their carbon retention capacities poses a serious risk. It is imperative that the institutions and policies currently being established as part of REDD+ readiness activities are resilient to future changes in the incentive structures facing tropical forest countries due to, e.g., climate policy induced demand for biofuels.     

Experimental evaluation of bird movements in a fragmented Neotropical landscape

The potential negative effects of forest fragmentation on animal movement and dispersal, and its consequences for population persistence, require an understanding of how modified landscapes affect movement decisions of forest species. We used a dispersal challenge experiment, whereby we released individuals of six bird species in a cattle pasture at different distances from forest edge (0, 50, 100 and 150 m), in a fragmented tropical landscape in Mexico to investigate the gap-crossing abilities and movement behavior of six species of tropical forest birds. Gaps as narrow as 50 m affected movement behavior of tropical forest birds. A sharp change in movement behavior in gaps 100 m and larger suggested the presence of a threshold distance beyond which birds are less likely to attempt and successfully navigate during trans-gap flights. Bird responses varied with degree of forest dependence: three forest-restricted species showed greater latency to cross gaps, independent of gap width, as compared with forest-unrestricted species. Gap width had a stronger effect on the orientation and destination of forest-restricted species than that of forest-unrestricted species. The concordance of our results with those found in species-distribution and radio-tracking studies indicates that dispersal challenge experiments provide reliable predictive information about response of forest birds to gaps between isolated forest fragments. In the landscape we studied, reducing gaps to no more than 50 m and providing corridors or shade trees between fragments should facilitate movements of forest birds.     

Nitrogen and phosphorus constrain labile and stable carbon turnover in lowland tropical forest soils

Tropical forests contain a large stock of soil carbon, but the factors that constrain its mineralization remain poorly understood. Microorganisms, when stimulated by the presence of new inputs of labile organic carbon, can mineralize (‘prime’) soil organic matter to acquire nutrients. We used stable carbon isotopes to assess how nutrient demand and soil properties constrain mineralization of added labile (sucrose) carbon and pre-existing (primed) soil carbon in tropical forest soils. In a series of lowland tropical forest soils from Panama, we found that the mineralization of fresh labile carbon was accelerated foremost by phosphorus addition, whereas the mineralization of pre-existing soil carbon was constrained foremost by nitrogen addition. However, there was variation in the relative importance of these nutrients in different soils and the largest effects on the acceleration of sucrose metabolism and constraint of priming occurred following the addition of nitrogen and phosphorus together. The respiration responses due to sucrose or primed soil carbon mineralization were reduced at pH below 4.8 and above 6.0. We conclude that in these tropical forest soils, phosphorus availability is more important in promoting microbial mineralization of sucrose carbon, whereas nitrogen availability is more important in constraining the priming of pre-existing soil organic carbon. This response likely arises because nitrogen is more closely coupled to organic matter cycling, whereas phosphorus is abundant in both organic and inorganic forms. These results suggest that the greatest impact of priming on soil carbon stocks will occur in moderately acidic tropical forest soils of low nitrogen availability. Given long-term changes in both atmospheric carbon dioxide and nitrogen deposition, the impact of priming effects on soil carbon in tropical forest soils may be partially constrained by the abundance of nitrogen.     

Interference by Iron in the Determination of Boron by ICP-OES in Mehlich-III Extracts and Total Element Digests of Tropical Forest Soils

Boron detection in soil extracts by inductively-coupled plasma optical-emission spectrometry (ICP-OES) can be influenced by iron interference, particularly in strongly weathered tropical forest soils. Boron concentrations in Mehlich-III extracts of 230 soils under lowland tropical forest in Panama were markedly overestimated at the most sensitive ICP-OES wavelength (249.772 nm) compared to a less sensitive but interference-free wavelength (208.957 nm) due to iron interference. Hot-water extracts contained insufficient iron to interfere in boron detection, but boron quantification in total element digests was affected strongly by iron interference at 249.772 nm. The relationship between boron overestimation and iron was used to correct a database of 300 Mehlich-III extractable boron measurements made at 249.772 nm for soils from a large forest dynamics plot. We recommend that boron measurements in tropical forest soils by ICP-OES should use the less sensitive 208.957 nm wavelength to avoid interference by extracted iron.