Variation in photosynthetic photon flux density within a tropical seasonal rain forest of Xishuangbanna, south-western China

Introduction Photosyntheticphotonfluxdensity(PPFD)withinforestcanopiesisintrinsicallyheterogeneousinspaceandtime.Becausesomespeciesaregenotypicallysuitedforspecificlightregimes,understandingtheheterogeneityofthelightregimewithinaforestcanopyisimportantfor…     

Effects of spatial autocorrelation and sampling design on estimates of protected area effectiveness

Estimating the effectiveness of protected areas (PAs) in reducing deforestation is useful to support decisions on whether to invest in better management of areas already protected or to create new ones. Statistical matching is commonly used to assess this effectiveness, but spatial autocorrelation and regional differences in protection effectiveness are frequently overlooked. Using Colombia as a case study, we employed statistical matching to account for confounding factors in park location and accounted for for spatial autocorrelation to determine statistical significance. We compared the performance of different matching procedures—ways of generating matching pairs at different scales—in estimating PA effectiveness. Differences in matching procedures affected covariate similarity between matched pairs (balance) and estimates of PA effectiveness in reducing deforestation. Independent matching yielded the greatest balance. On average 95% of variables in each region were balanced with independent matching, whereas 33% of variables were balanced when using the method that performed worst. The best estimates suggested that average deforestation inside protected areas in Colombia was 40% lower than in matched sites. Protection significantly reduced deforestation, but PA effectiveness differed among regions. Protected areas in Caribe were the most effective, whereas those in Orinoco and Pacific were least effective. Our results demonstrate that accounting for spatial autocorrelation and using independent matching for each subset of data is needed to infer the effectiveness of protection in reducing deforestation. Not accounting for spatial autocorrelation can distort the assessment of protection effectiveness, increasing type I and II errors and inflating effect size. Our method allowed improved estimates of protection effectiveness across scales and under different conditions and can be applied to other regions to effectively assess PA performance.     

Efficacy of extracting indices from large‐scale acoustic recordings to monitor biodiversity

Passive acoustic monitoring could be a powerful way to assess biodiversity across large spatial and temporal scales. However, extracting meaningful information from recordings can be prohibitively time consuming. Acoustic indices (i.e., a mathematical summary of acoustic energy) offer a relatively rapid method for processing acoustic data and are increasingly used to characterize biological communities. We examined the relationship between acoustic indices and the diversity and abundance of biological sounds in recordings. We reviewed the acoustic‐index literature and found that over 60 indices have been applied to a range of objectives with varying success. We used 36 of the most indicative indices to develop a predictive model of the diversity of animal sounds in recordings. Acoustic data were collected at 43 sites in temperate terrestrial and tropical marine habitats across the continental United States. For terrestrial recordings, random‐forest models with a suite of acoustic indices as covariates predicted Shannon diversity, richness, and total number of biological sounds with high accuracy (R² ≥ 0.94, mean squared error [MSE] ≤170.2). Among the indices assessed, roughness, acoustic activity, and acoustic richness contributed most to the predictive ability of models. Performance of index models was negatively affected by insect, weather, and anthropogenic sounds. For marine recordings, random‐forest models poorly predicted Shannon diversity, richness, and total number of biological sounds (R² ≤ 0.40, MSE ≥ 195). Our results suggest that using a combination of relevant acoustic indices in a flexible model can accurately predict the diversity of biological sounds in temperate terrestrial acoustic recordings. Thus, acoustic approaches could be an important contribution to biodiversity monitoring in some habitats.     

Fragmented forest in tropical landscape--the case of the state of Selangor,Malaysia

This paper presents the pattern and changes of fragmented forest in relation with changes of total forest cover in the state of Selangor in three decades.In this study,inventoried forest cover maps of Selangor in 1971/1972,1981/1982 and 1991/1992 produced by the Forestry Department of Peninsular Malaysia were digitized to examine the changes in area and number of fragmented forest.Results showed that in 1971/1972,16 fragmented forests were identified in Selangor.All fragmented forests were identified as diptercoarp forest.A decade later the number of fragmented forests increased by approximately 44%(23).Of the 23 fragmented forests,two were peat swamp forests whereas the remaining were dipterocarp forests.In 1991/1992 the number of fragmented forests(12)was reduced by 47.8%.Two of the fragmented forests were Fragmentation of both dipterocrp and peat swamp forests occurred profoundly during the period between 1971/1972and 1981/1982,which consequently increased the number of fragmented forests compared with before the period of 1971/1972 where fragmentation happened only at dipterocarp forests.However,many fragmented forests vanished between the 1981/1982 and 1991/1992 periods.     

Termite assemblages in a West-African semi-deciduous forest and teak plantations

Responses of termite assemblages to the conversion of semi-deciduous forest into teak plantations were studied in the Lama Forest Reserve in Benin, West Africa. Four belt transect surveys were run in each of the two forest types, adopting a modified termite diversity assessment protocol. Termite assemblages were remarkably species-poor in both forest types, with only 19 species encountered altogether. The low species richness was due to the rarity of soil-feeders of the soil/humus interface and the absence of true soil-feeders in the compact vertisol soil. Species richness was significantly higher in semi-deciduous forest than in teak plantations, but termite encounters were significantly lower. Termite assemblage and feeding group structure differed significantly among forest types. Wood-feeders were recorded only in semi-deciduous forest. In contrast, fungus-growers were more species-rich and about four times more abundant in teak plantations, mainly due to one Ancistrotermes species. The humification score, which depicts the position of termite assemblages along a gradient of increasing humification of their food substrate, was significantly higher in teak plantations, due to the absence of wood-feeders and the preponderance of fungus-growers. Combined principal components and multiple regression analysis identified two significant predictors of termite assemblages, soil water content and leaf litter biomass. The abundance of fungus-growers in teak plantations seemed to be mainly related to the high leaf litter biomass. Indirect evidence also suggests that lower predation pressure by ants on termites in teak plantations may have contributed to the abundance of termites.     

华南引种优质牧草气候适应性的研究

本文对我国南方有发展前途的三种热带牧草和三种温带牧草所历时两年的分期播种试验进行了总结。试验研究表明,热带牧草与温带牧草的生长发育、产草量形成与气象条件关系密切。同时还对热带牧草越冬、温带牧草越夏的气象指标进行了鉴定。分别找到了热带牧草的霜冻指标、平流寒害指标以及温带牧草的热害指标。此外,还对华南引种优质热带牧草和温带牧草进行了气候适应性评价。合理布局问题亦进行了探讨。并提出华南地区建设人工草场宜牧林农结合,中小型为主的观点。     

纳板河自然保护区参与性有效管理研究初探

纳板河自然保护区内农民落后的耕作方式，对土地的不合理利用以及政策和社会发展等因素对热带雨林带来巨大压力。对其实施有效管理，合理利用土地和野生生物资源，开征资源补偿素，完善管理体制和规章制度，可在帮助当地农民脱贫的同时，有效地保护热带雨林及其生境。     

Estimating baseline carbon emissions for the Eastern Panama Canal watershed

To participate in the potential market for carbon credits based on changes in the use and management of the land, one needs to identify opportunities and implement land-use based emissions reductions or sequestration projects. A key requirement of land-based carbon (C) projects is that any activity developed for generating C benefits must be additional to business-as-usual. A rule-based model was developed and used that estimates changes in land-use and subsequent carbon emissions over the next twenty years using the Eastern Panama Canal Watershed (EPCW) as a case study. These projections of changes in C stocks serve as a baseline to identify where opportunities exist for implementing projects to generate potential C credits and to position Panama to be able to participate in the emerging C market by developing a baseline under scenarios of business-as-usual and new-road development. The projections show that the highest percent change in land use for the new-road scenario compared to the business-as-usual scenario is for urban areas, and the greatest cause of C emission is from deforestation. Thus, the most effective way to reduce C emissions to the atmosphere in the EPCW is by reducing deforestation. In addition to affecting C emissions, reducing deforestation would also protect the soil and water resources of the EPCW. Yet, under the current framework of the Clean Development Mechanism (CDM), only credits arising from reforestation are allowed, which after 20 years of plantation establishment are not enough to offset the C emissions from the ongoing, albeit small, rate of deforestation in the EPCW. The study demonstrates the value of spatial regional projections of changes in land cover and C stocks: The approach helps a country identify its potential greenhouse gas (GHG) emission liabilities into the future and provides opportunity for the country to plan alternative development pathways. It could be used by potential project developers to identify which types of projects will generate the largest C benefits and provide the needed baseline against which a project is then evaluated. Spatial baselines, such as those presented here, can be used by governments to help identify development goals. The development of such a baseline, and its expansion to other vulnerable areas, well positions Panama to respond to the future market demand for C offsets. It is useful to compare the projected change in land cover under the business-as-usual scenario to the goals set by Law 21 for the year 2020. Suggested next steps for analysis includeusing the modeling approach to exploreland-use, C dynamics and management ofsecondary forests and plantations, soilC gains or losses, sources ofvariability in the land use and Cstock projections, and other ecologicalimplications and feedbacks resulting fromprojected changes in land cover.     

Baseline Carbon Stocks Assessment and Projection of Future Carbon Benefits of a Carbon Sequestration Project in East Timor

Climate change is one of the most pressing environmental problems humanity is facing today. Forest ecosystems serve as a source or sink of greenhouse gases, primarily CO₂. With support from the Canadian Climate Change Fund, the Community-based Natural Resource Management for Carbon Sequestration project in East Timor (CBNRM-ET) was implemented to “maintain carbon (C) stocks and increase C sequestration through the development of community-based resource management systems that will simultaneously improve livelihood security”. Project sites were in the Laclubar and Remexio Sub-districts of the Laclo watershed. The objective of this study was to quantify baseline C stocks and sequestration benefits of project components (reforestation with fast-growing species, primarily Casuarina equisetifolia, and agroforestry involving integration of Paraserianthes falcataria). Field measurements show that mature stands (≥30 years) of P. falcataria and C. equisetifolia contain up to 200 Mg C ha⁻¹ in above ground biomass, indicating the vast potential of project sites to sequester carbon. Baseline C stocks in above ground biomass were very low in both Laclubar (6.2 Mg C ha⁻¹ for reforestation sites and 5.2 Mg C ha⁻¹ for agroforestry sites and Remexio (3.0 Mg C ha⁻¹ for reforestation and 2.5 Mg C ha⁻¹ for agroforestry). Baseline soil organic C levels were much higher reaching up to 160 Mg C ha⁻¹ in Laclubar and 70 Mg C ha⁻¹ in Remexio. For the next 25 years, it is projected that 137 671 Mg C and 84 621 Mg C will be sequestered under high- and low C stock scenarios, respectively.     

热带滨海景观设施的腐蚀特征及其影响因素简析

目的 研究热带滨海地区景观设施的腐蚀特征及影响因素.方法 通过宏观调查和微区检查的方法,对比分析湛江、珠海和深圳3个典型的热带滨海城市景观设施腐蚀状况的差异,总结热带滨海景观设施的腐蚀特征.结果 缝隙腐蚀和焊缝腐蚀是热带滨海景观设施发生频次最高的腐蚀类型,其中出现缝隙腐蚀的频次平均为66.6％,出现焊缝腐蚀的频次平均为53.2％.随着离海岸距离的增大,景观设施腐蚀程度减小,其中景观设施在200 m发生大面积腐蚀的程度比100 m平均减轻22.1％.景观设施向海面发生严重腐蚀的比例比背海面高,其中景观设施向海面在100 m发生腐蚀比背海面严重,比200 m平均增高10.4％.结论 热带滨海地区景观设施的腐蚀差异与设施离海距离、设施朝向以及热带海洋大气环境要素(相对湿度和大气污染物浓度)密切相关.