Effects of selective logging on the arboreal ants of a Bornean rainforest

We examined the effect of selective logging and corresponding forest canopy loss on arboreal ant diversity in a tropical rainforest. Arboreal ants were collected from an unlogged forest plot and from forest plots selectively logged 14 years and 24 years earlier in Danum Valley, Sabah, Malaysia, using a canopy fogging method. Selective logging was associated with a significant decrease in canopy cover and an increase in understory vegetation density relative to unlogged forest. Our study showed that selective logging in primary forest might not dramatically decrease total species number and overall abundance of arboreal ants; however, it may influence the species composition and dominance structure of the ant community, accompanied by an increase in abundance of shrub‐layer species and trophobiotic species. In view of the results of this study, management techniques that minimize logging impact on understory vegetation structure are likely to help maintain the conservation value of logged forests for arboreal ants. Our results also suggest that accurate assessment of the impacts on biodiversity should not be based only on measurement of species number and overall abundance, but also on analysis of species composition and community structure.     

Functional diversity and traits assembly patterns of lichens as indicators of successional stages in a tropical rainforest

Understanding community assembly patterns with regard to functional traits, which may be common to different species, allows us to compare ecological communities in a wider range of environmental and phytogeographic conditions. Moreover, a functional approach may facilitate the comprehension of the relation between biotic changes and ecosystem functions in complex systems such as tropical forests. Considering the lack of information in relation to the influence of environmental conditions on lichen functional traits, on lichen functional patterns in tropical forests and the potential usage of this approach in bioindication studies, this paper aims at (i) determining the functional structure of the lichen communities along the forest succession gradient, (ii) assessing the relation of lichen functional traits to this gradient and (iii) verifying the potential of using lichen functional traits as indicators of successional stages in tropical rainforests. Lichens were sampled in 24 sampling units of three successional stages (6–10; 12–20; and 40–60 years of recovering). The results corroborated our main hypothesis that the functional structure of the lichen communities responds to structural changes along a forest regeneration gradient. Growth forms (foliose, fruticose and crustose) as well as some reproductive trait states (lirella, isidia and perithecia) were the most suitable lichen traits to be used as indicators of forest succession in the southern edge of the Atlantic Rainforest. Lirella, fruticose and foliose were more related to earlier successional stages; isidia was more related to intermediate stages, while perithecia and crustose were more related to older stages. These results reinforce the ability of lichens to be used as bioindicators of forest conditions.     

Species' traits predict the effects of disturbance and productivity on diversity

Disturbance is an important factor influencing diversity patterns. Ecological theory predicts that diversity peaks at intermediate levels of disturbance, but this pattern is not present in a majority of empirical tests and can be influenced by the level of ecosystem productivity. We experimentally tested the effects of disturbance on diversity and show that species' autecological traits and community relations predicted species loss. We found that – alone or in concert – increasing disturbance intensity or frequency, or decreasing productivity, reduced diversity. Our species did not exhibit a clear competition-colonization trade-off, and intrinsic growth rate was a more important predictor of response to disturbance and productivity than measures of competitive ability. Furthermore, competitive ability was more important in predicting responses when, in addition to killing individuals, disturbance returned nutrients to the ecosystem. Our results demonstrate that species' traits can help resolve conflicting patterns in the response of diversity to disturbance and productivity.     

The use of ants and other soil and litter arthropods as bio-indicators of the impacts of rainforest clearing and subsequent land use

The present study investigated the impacts of rainforest clearance, and associated subsequent land␣use for pasture, on assemblages of soil and litter arthropods in eastern subtropical Australia. We assessed the utility of soil and litter arthropods as potential bio-indicators of cleared and forested habitats. Arthropods were sampled from 24 sites (12 sites each in rainforest and pasture) using two methods (extraction from litter, pitfall traps). Responses of taxa were analysed at various levels of taxonomic resolution, including ‘coarse’ arthropods (all arthropods sorted to Order/Class), ant genera and ant species. Multivariate analyses of arthropod composition indicated that an increase in the level of taxonomic resolution did not provide a commensurate increase in the sensitivity of assemblage response. Indicator values (IndVals), computed for each taxon, showed that a number of arthropod taxa may have potential as bio-indicators of habitat change. However the use of many of these, especially many ant species found in our study, may be unreliable because even after extensive numbers of sites were sampled, most species showed patchy distributions. To overcome this problem, we generated ‘composite indices’, by combining information from sets of indicator taxa. The utility of these composite indices is discussed.     

南亚热带人工针叶纯林近自然改造早期对群落特征和土壤性质的影响

借鉴近自然森林管理理念,用阔叶林或针阔混交林替代南亚热带大面积人工针叶纯林已被认为是一种有效的森林培育方式.1993年,在位于广西凭祥的中国林业科学研究院热带林业实验中心伏波试验场营造了马尾松和杉木纯林.为了提高针叶纯林的生产力和维护生态平衡,2007-2008年间,运用近自然森林培育技术,分别在间伐后的马尾松和杉木纯林中套种等量混合的当地优质乡土树种红椎(Castanopsis hystrix)和香梓楠(Michelia gioii苗木,套种密度均为405株/hm2(以下简称“马尾松近自然林”、“杉木近自然林”).选择邻近地块相同林龄、相似立地条件的未经改造的马尾松、杉木人工纯林作为对照(以下简称“未改造纯林”),研究了马尾松和杉木人工针叶纯林近自然改造早期对群落特征和土壤性质的影响,以期为马尾松和杉木人工林的可持续经营提供科学依据.研究结果表明:(1)近自然林中马尾松和杉木的密度、胸高断面积均显著低于各自未改造纯林(P＜0.05),但其平均胸径均高于各自未改造纯林,其中马尾松达显著差异(P＜0.05).(2)近自然林成年树(DBH≥10 cm)的林木株数少于未改造纯林,树种仍以马尾松和杉木占据绝对优势地位,而近自然林小树(5 cm≤DBH＜10 cm)和幼树(1 cm≤DBH＜5 cm)的物种数、株数均多于未改造纯林,套种的红椎和香梓楠已经成为近自然林中重要值最大的幼树物种,红椎和香梓楠在马尾松近自然林中的生长状况优于杉木近自然林.(3)马尾松近自然林灌木层和草本层的物种丰富度指数、Shannon-Wiener指数、Simpson指数和Pielou指数与其未改造纯林均无显著差异;杉木近自然林灌木层的丰富度指数和草本层的Pielou指数显著高于其未改造纯林(P＜0.05),其他指数则没有显著差异.(4)马尾松和杉木近自然林的土壤容重、总孔隙度、全磷、全氮、全钾和速效钾与各自未改造纯林没有显著差异,但马尾松近自然林的土壤有机碳含量和pH值显著低于其未改造纯林(P＜0.05),杉木近自然林的速效磷含量显著低于其未改造纯林(P＜0.05).     

Macaranga and Mallotus species (Euphorbiaceae) as indicators for disturbance in the mixed lowland dipterocarp forest of East Kalimantan (Indonesia)

The indicator value (IV) of Macaranga and Mallotus species (Euphorbiaceae) for different types of disturbance in lowland dipterocarp forest was assessed by counting and identifying all individuals of species of these genera taller than 30 cm in 45 (10 m×300 m) plots at nine locations. Twelve Macaranga and nine Mallotus species were found. The main forest disturbance types (primary forest, secondary forest, selectively logged forest, forest burned once, and repeatedly burned forest used for shifting-cultivation) each had their own set of indicator species. The level of disturbance in the forest types was assessed by measuring nine forest structural parameters. The occurrence of Macaranga and Mallotus species was closely related to the level of disturbance in a forest. Most Macaranga species were characteristic of high disturbance levels, while most Mallotus species preferred intermediate to low levels of disturbance. However, both genera had species at both disturbance extremes. Using multiple regression analysis, combinations of Macaranga and Mallotus species were formed and used to predict the separate forest structural parameters and the general level of disturbance of a forest. The Macaranga and Mallotus species could be grouped into (1) primary forest ‘remnant’ species; (2) generalist pioneer species; and (3) high disturbance pioneer species.     

The use of a functional approach as surrogate of Collembola species richness in European perennial crops and forests

Collembolans are known indicators of soil disturbance, used in several soil biodiversity monitoring programmes. As for other groups of soil microarthropods, taxonomic determination of Collembola species requires a huge effort and expert knowledge. In this study, we evaluated whether identification of Collembola species to the morphotype level, using an eco-morphological index which classifies individuals based on their adaptation to the soil, can be used as a surrogate of species richness in extensive monitoring schemes. The same evaluation was performed for higher taxa surrogates, using taxonomic categories at the genus and family levels. Additionally, sampling effort for perennial crops and forest systems was determined. Species data were collected from 35 sites sampled within different projects with the same number of samples (16 per site). Results showed that, on average, 8–12 samples are enough to have a good estimate of species richness for this type of systems, averaging 80–90%, but varying considerably with site habitat heterogeneity and local Collembola species pool. GLM models (using species richness as response variable) fitted for family, genus or morphotype levels (explanatory variables) were all significant (p < 0.05) but only the latter two had a pseudo R² higher than 0.75. This indicates that when a rapid, cost-effective assessment of Collembola richness in different sites is required, this eco-morphological trait approach, as well as the determination to the genus level, could be used.     

The effects of rainforest canopy loss on arboreal dung beetles in Borneo: implications for the measurement of biodiversity in derived tropical ecosystems

We examine the effect of selective timber extraction, and corresponding forest canopy loss, on arboreal dung beetles in the tropical rainforests of Sabah, Malaysian Borneo. Changes in vertical distribution of beetles are measured through differences in the abundance of beetles in ground-based pitfall traps in primary, logged and plantation forest. Previous research has demonstrated that arboreal dung beetles are not generally collected in pitfall traps in primary forest, but are present in large numbers above the ground in canopy vegetation: the presence of arboreal beetles in pitfalls in areas of reduced or modified canopy cover may therefore reflect a response to the absence or modification of their usual habitat, and the proliferation of these beetles nearer to the ground. In this paper, statistically significant differences are found in the abundance of beetles in ground pitfall traps from logged forest compared to primary forest. Results show that virtually no arboreal dung beetles are recorded in primary forest traps, with an increased abundance of arboreal dung beetles in traps from logged and plantation forest, with 1.72% of the total number of arboreal beetles recorded from primary forest, 22.32% from logged forest, and 75.96% from plantation forest. The presence of arboreal dung beetles in plantations demonstrates that arboreal dung beetles can survive outside their normal habitat, and we relate these observations to adaptations to upper rainforest canopy conditions, and proliferation of these microclimatic conditions in man-made habitats. Results are also discussed in terms of their relevance to the measurement of species richness and diversity in logged and other derived ecosystems, where mixing of the ground-based and arboreal faunas occurs.     

Effects of environmental and spatial gradients on Quercus-dominated Mountain forest communities in the Hindu-Kush ranges of Pakistan

Quercus-dominated forests are among the most important broad-leaved evergreen forests of the Hindu Kush ranges and are currently prone to drastic anthropogenic and climatic changes. The aim of this study was to provide basic data for the development of a regional oak forest ecosystem framework for ecological restoration and management plan development to maintain local peoples’ livelihoods. Hence, we analyzed distribution patterns and environmental factors that affect regional oak forests’ species composition and diversity. Ward’s Agglomerative clustering divided oak-dominated forest communities into three groups: i.e., Group I, dominated by Quercus baloot had an importance value index (IVI) of 89.87 ± 4.31, Group II, dominated by Quercus dilatata had an IVI of 32.16 ± 15.01, and Group III, dominated by Quercus oblongata had an IVI of 83.14 ± 4.67, respectively. The environmental factors which vary significantly within these communities were latitude, elevation, clay content and bulk density of the soil. Wilting point, saturation point, and electrical conductivity were also considered as ecosystem structural variables. Canonical correspondence analysis (CCA) indicated that community structure was affected by various environmental factors including precipitation, slope angle, elevation, clay content, and relative humidity.     

博斯腾湖湖滨湿地植物多样性对季节变化的响应

研究生物多样性对季节的响应对于维持生态系统稳定、保护生物多样性、解析群落构建机制具有重要意义。本文以博斯腾湖湖滨湿地为研究对象,探究不同季节植物群落的物种多样性与功能多样性的变化规律。结果显示：(1)物种多样性指数随季节变化没有显著改变;功能多样性指数中,功能丰富度由春季到夏季逐渐减小,功能离散度逐渐增大;不同季节的功能均匀度差异性不显著;(2)植物功能性状在不同季节间差异显著;春季叶绿素含量显著低于夏季;夏季比叶面积和叶干物质含量显著高于秋季;叶片含水量和厚度由春季到秋季呈递增趋势;(3)影响Pielou指数和功能丰富度的主要环境因子分别为土壤铵态氮和速效磷;影响Shannon-Wiener指数、Simpson指数和功能均匀度的主要环境因子为土壤有机质;影响功能离散度的主要环境因子为土壤含水量;(4)影响最大株高的主要环境因子为土壤pH值;影响叶干物质含量的主要环境因子为土壤速效钾;影响叶片厚度和比叶面积的主要环境因子为土壤总磷;而影响叶片含水量的主要环境因子为土壤硝态氮;叶绿素含量与土壤因子无显著相关关系。     

Neotropical dragonflies (Insecta: Odonata) as indicators of ecological condition of small streams in the eastern Amazon

Sensitive and cost‐effective indicators of aquatic ecosystem condition in Amazon streams are necessary to assess the effects of anthropogenic disturbances on those systems in a viable and ecologically meaningful manner. We conducted the present study in the municipality of Paragominas, state of Pará, northern Brazil, where we sampled adult dragonflies in 50 100‐m‐long wadeable stream sites in 2011. We collected 1769 specimens represented by 11 families, 41 genera and 97 species. The suborder Zygoptera contributed 961 individuals and Anisoptera 808. Among the 97 recorded species, nine were classified as useful indicators of ecological condition, with four species being associated with more degraded streams (three Anisoptera, one Zygoptera) and five with more preserved streams (all were Zygoptera). Anisoptera (dragonflies) tend to provide more useful indicators of more degraded environments because they have more efficient homeostatic mechanisms and are more mobile, enabling them to tolerate a wider range of environmental conditions. By contrast, Zygoptera (damselflies) tend to provide a more useful role as indicators of more preserved environments and high levels of environmental heterogeneity because of their smaller body sizes and home ranges and greater ecophysiological restrictions. We conclude from our assessment of this low‐order Amazonian stream system that (i) the occurrence of specific odonate species is strongly associated with the configuration of riparian vegetation, (ii) agricultural activities appear to be the main factor determining changes in the composition of odonate assemblages and (iii) these insects can act as useful indicators of the ecological consequences of riparian habitat loss and disturbance. Because generalist species invade moderately degraded areas, those areas may have high species richness but host few species of Zygoptera. Therefore, preserving dense riparian vegetation is necessary to maintain aquatic ecological condition, and that condition can be rehabilitated by planting new trees. Both require enforcing existing environmental regulations, various types of incentives and educating local communities.     

河西走廊天然固沙植被区地表甲虫多样性及其对沙漠化的指示作用

干旱、半干旱区沙漠化强烈影响动植物分布及多样性,地表甲虫是荒漠中主要的动物类群,它们对沙漠化引起的植被和土壤环境变化响应十分敏感。鉴于此,以河西走廊中部张掖绿洲外围的天然固沙植被区作为研究区,依据沙漠化发育程度选择流动沙丘（ASD）、丘间低地（IL）、半固定（SFSD）和固定沙丘（FSD）4种生境,调查了地表甲虫群落组成及影响甲虫分布的植被和土壤环境。研究发现,4种生境地表甲虫群落组成明显不同并存在季节变异,5月ASD与IL、SFSD和FSD生境地表甲虫群落的相异性大于8月。5月和8月SFSD生境地表甲虫活动密度均显著高于其他生境,8月FSD生境地表甲虫多样性指数显著高于其他生境。不同大小甲虫对沙漠化的响应模式不同,大中型甲虫对沙漠化的响应较小型甲虫敏感,这在5月表现尤为明显。地表甲虫与环境因子的RDA分析结果表明,12个植被和土壤环境因子解释了49.8%的地表甲虫群落变异,其中植被环境解释了甲虫群落变异的16.3%,土壤环境解释了甲虫群落变异的4.2%,植被和土壤环境相互作用解释了甲虫群落变异的29.3%。pRDA分析结果表明,草本物种丰富度、灌木盖度、土壤有机碳含量和粗砂含量是影响地表甲虫分布的主要环境因子,它们解释了43.7%的地表甲虫群落变异。Pearson相关分析表明,草本物种丰富度与地表甲虫活动密度呈显著正相关,而与地表甲虫均匀度呈显著负相关;灌木盖度与地表甲虫多样性呈显著正相关;地表甲虫物种丰富度与灌木盖度和草本物种丰富度均呈显著正相关。此外,研究还发现戈壁琵甲、克氏扁漠甲、中华砚甲和甘肃齿足象可以用于指示FSD生境,东鳖甲属昆虫可以用于指数SFSD生境,谢氏宽漠王可以用于指示IL及ASD生境。     

Environmental heterogeneity and disturbance by humans control much of the tree species diversity of Atlantic montane forest fragments in SE Brazil

The effects of human impact and environmental heterogeneity on the tree species diversity were assessed in 20 fragments of tropical montane seasonal forest in southeastern Brazil. Previous surveys of the tree community, soils and topography of the fragments provided the bulk of the data. The diversity parameters used were the means of species richness, Shannon diversity (H′), and Pielou evenness (J′) obtained from “bootstrap” sub-samplings of 1,000 trees. Morphometric variables obtained for the fragments included total, edge, and inner areas. Investigation forms were used to survey the history of human interventions and prepare an impacts matrix containing scores assigned to assess the extent, severity and duration of selected impacts. Scores for overall environmental impacts were obtained from the ordination scores produced by a multivariate analysis of the impacts matrix. A multivariate analysis of the standard deviations of soil variables was used to identify the variable which contributed most to soil heterogeneity. The same procedure was repeated for the variables related to topography and ground-water regime. The three species diversity parameters were related to the proportions of edges, the overall impacts scores, and the standard deviations of two selected soil and topographic variables. The species diversity in the fragments increased with increasing heterogeneity of both soil chemical properties and topographic features, and decreased with increasing proportion of forest edges. The evenness component of species diversity also increased with increasing severity of overall environmental impacts. This probably occurred because the 20 fragments did not include highly disturbed forests in the range and the intermediate disturbance effect on species diversity was therefore detected.     

A novel comparative research platform designed to determine the functional significance of tree species diversity in European forests

One of the current advances in functional biodiversity research is the move away from short-lived test systems towards the exploration of diversity-ecosystem functioning relationships in structurally more complex ecosystems. In forests, assumptions about the functional significance of tree species diversity have only recently produced a new generation of research on ecosystem processes and services. Novel experimental designs have now replaced traditional forestry trials, but these comparatively young experimental plots suffer from specific difficulties that are mainly related to the tree size and longevity. Tree species diversity experiments therefore need to be complemented with comparative observational studies in existing forests. Here we present the design and implementation of a new network of forest plots along tree species diversity gradients in six major European forest types: the FunDivEUROPE Exploratory Platform. Based on a review of the deficiencies of existing observational approaches and of unresolved research questions and hypotheses, we discuss the fundamental criteria that shaped the design of our platform. Key features include the extent of the species diversity gradient with mixtures up to five species, strict avoidance of a dilution gradient, special attention to community evenness and minimal covariation with other environmental factors. The new European research platform permits the most comprehensive assessment of tree species diversity effects on forest ecosystem functioning to date since it offers a common set of research plots to groups of researchers from very different disciplines and uses the same methodological approach in contrasting forest types along an extensive environmental gradient.     

三峡水库坝下江心洲植物群落及其性状对不同水淹强度的响应

三峡水库的运行,改变了其坝下游的水沙情势,使坝下游沙洲生境呈现出明显的水淹强度梯度变化。阐明这一梯度变化下沙洲植被组成、分布和性状结构特征,是理解植被与沙洲稳定关系的基础,更是阐明三峡工程对长江中下游地区生态环境影响的核心内容之一。选取上荆江河段第一个江心洲-太平口心滩作为研究样地,通过植被组成和分布特征的调查,对不同水淹强度下群落物种组成、多样性和功能特征进行了深入分析。结果表明：太平口心滩植被组成以草本植物为主,稀布小型灌木川三蕊柳。调查共记录物种21科33属39种,以禾本科和菊科植物为主要优势种。轻微（20-40 d）和极强水淹强度（100+d）条件下的生境物种组成同其他水淹强度生境具有显著性差异,轻微水淹强度下牛鞭草和节节草为主要优势种,极强水淹强度下虉草为主要优势种。不同水淹强度下物种多样性指数差异显著,功能多样性指数和生物多样性指数趋势基本一致。随着水淹时间的延长,植被更倾向于表现出花果期位于出露期、植株高度更加低矮、须根系、进行营养繁殖的功能性状。江心洲植被的群落结构和功能性状特征都在水淹梯度下呈现出明显的梯度变化特征。这些研究结果表明水淹强度的梯度变化是沙洲植物群落变化的重要驱动因子,为进一步研究沙洲植物群落动态变化以及沙洲植被协同演替机制,明晰大坝影响下的生态环境变化提供重要依据。     

Applying climatically associated species pools to the modelling of compositional change in tropical montane forests

Aim Predictive species distribution modelling is a useful tool for extracting the maximum amount of information from biological collections and floristic inventories. However, in many tropical regions records are only available from a small number of sites. This can limit the application of predictive modelling, particularly in the case of rare and endangered species. We aim to address this problem by developing a methodology for defining and mapping species pools associated with climatic variables in order to investigate potential species turnover and regional species loss under climate change scenarios combined with anthropogenic disturbance. Location The study covered an area of 6800 km² in the highlands of Chiapas, southern Mexico. Methods We derived climatically associated species pools from floristic inventory data using multivariate analysis combined with spatially explicit discriminant analysis. We then produced predictive maps of the distribution of tree species pools using data derived from 451 inventory plots. After validating the predictive power of potential distributions against an independent historical data set consisting of 3105 botanical collections, we investigated potential changes in the distribution of tree species resulting from forest disturbance and climate change. Results Two species pools, associated with moist and cool climatic conditions, were identified as being particularly threatened by both climate change and ongoing anthropogenic disturbance. A change in climate consistent with low‐emission scenarios of general circulation models was shown to be sufficient to cause major changes in equilibrium forest composition within 50 years. The same species pools were also found to be suffering the fastest current rates of deforestation and internal forest disturbance. Disturbance and deforestation, in combination with climate change, threaten the regional distributions of five tree species listed as endangered by the IUCN. These include the endemic species Magnolia sharpii Miranda and Wimmeria montana Lundell. Eleven vulnerable species and 34 species requiring late successional conditions for their regeneration could also be threatened. Main conclusions Climatically associated species pools can be derived from floristic inventory data available for tropical regions using methods based on multivariate analysis even when data limitations prevent effective application of individual species modelling. Potential consequences of climate change and anthropogenic disturbance on the species diversity of montane tropical forests in our study region are clearly demonstrated by the method.     

恢复方式和地形对晋西黄土区退耕林分物种多样性的影响

运用样带样方调查法,对比不同恢复方式和地形条件下退耕林分的物种多样性,以期为晋西黄土区植被恢复效果评价和经营管理提供参考.结果表明: 恢复方式对退耕林分物种多样性具有显著影响.自然恢复林物种数为刺槐人工林的 1.6倍,Shannon 指数大于刺槐人工林,Pielou 指数小于刺槐人工林.物种多样性受坡位影响显著,各指数均表现为沟底>沟坡>梁峁坡>梁峁顶;坡向对退耕林分物种多样性影响不显著,各指数均表现为阴坡>阳坡.物种多样性受地形和恢复方式综合作用影响显著,在自然恢复林阴坡沟底处最高,物种均匀度在刺槐人工林阴坡沟底处最高.从提高物种多样性角度,黄土区植被恢复在遵循适地适树原则的同时,应参照自然恢复林分,在不同地形部位采用不同的造林设计.