Status of forests in Uganda

Trees, forests and woodlands cover about 14% of Uganda’s land surface. Over the last 30–40 years, growth in human population and corresponding increase in demand for forest products for domestic and industrial use, expansion of agricultural land, illegal settlements and weak forest management capacity have adversely affected the status of natural forests in Uganda, particularly the biodiversity. Until recently, little attention had been paid to development of commercial forests which should have provided alternative forest products and services to relieve the pressure on natural forests and conserve biodiversity. As a result, Uganda’s forests have been degraded, and in some cases, the biodiversity has been eroded. There is a need for regular data collection and monitoring of the status of the forests in terms of areal extent, distribution, plantation species introductions and biodiversity.     

Disrupted montane forest recovery hinders biodiversity conservation in the tropical Andes

Aim

Andean montane forests are biodiversity hotspots and large carbon stores and they provide numerous ecosystem services. Following land abandonment after centuries of forest clearing for agriculture in the Andes, there is an opportunity for forest recovery. Field-based studies show that forests do not always recover. However, large-scale and long-term knowledge of recovery dynamics of Andean forests remains scarce. This paper analyses tropical montane forest recovery trajectories over a 15-year time frame at the landscape and tropical Andean scale to inform restoration planning.

Methods

We first detect “potential recovery” as areas that have experienced a forest transition between 2000 and 2005. Then, we use Landsat time series analysis of the normalized difference water index (NDWI) to classify four “realized recovery” trajectories (“ongoing”, “arrested”, “disrupted” and “no recovery”) based on a sequential pattern of 5-yearly Z-score anomalies for 2005–2020. We compare these results against an analysis of change in tree cover to validate against other datasets.

Results

Across the tropical Andes, we detected a potential recovery area of 274 km² over the period. Despite increases in tree cover, most areas of the Andes remained in early successional states (10–25% tree cover), and NDWI levelled out after 5–10 years. Of all potential forest recovery areas, 22% showed “ongoing recovery”, 61% showed either “disrupted” or “arrested recovery”, and 17% showed “no recovery”. Our method captured forest recovery dynamics in a Peruvian arrested succession context and in landscape-scale tree-planting efforts in Ecuador.

Main conclusions

Forest recovery across the Andes is mostly disrupted, arrested or unsuccessful, with consequences for biodiversity recovery and provision of ecosystem services. Low-recovery areas identified in this study might be good candidates for active restoration interventions in this UN Decade on Restoration. Future studies could determine restoration strategies and priorities and suggest management strategies at a local planning scale across key regions in the biodiversity hotspot.     

The impact of land use and land cover change on biodiversity within and adjacent to Kibasira Swamp in Kilombero Valley,Tanzania

Wetlands are crucial ecosystems with multiple values and functions to a range of different stakeholders. The future of wetlands depends both on the legacy of the past and how they are currently used. Using 48 vegetation survey plots (0.08 ha) combined with Landsat 5 and 7 TM imagery, we assessed the influence of long‐term (1990–2011) land use and land cover change on the biodiversity of the Kibasira Swamp. Information on perceptions of adjacent communities on historical changes and drivers for the changes were also collected. Results showed an increase in the area covered by open water by 1% and forest by 4% between 1990 and 1998 whilst Cyperus papyrus L and cultivated land area decreased by 8% and 3%, respectively on the same period. Between 1998 and 2011, there was a decrease in areas covered by water by 35% and forest by 9% whereas C. papyrus L increased by 40% and cultivated land increased by 8%. These changes have affected the biodiversity of the swamp and adjacent to it as numbers of mammals have declined. However, the Swamp still provides extensive habitat for plants and bird species despite the ongoing human pressure. Interventions may be necessary to maintain biodiversity in Kibasira Swamp to ensure sustainable ecosystem services.     

海河流域森林生态系统服务功能评估

森林生态系统在流域中发挥着极其重要的生态作用,为流域发展提供着巨大的服务功能。本研究根据生态系统服务功能的内涵,建立了流域森林生态系统服务功能评价指标体系,利用市场价值法、影子工程法和生产成本法等,定量评价了海河流域森林生态系统服务功能的经济价值。结果表明：海河流域森林生态系统总价值2349.4亿元,其中直接价值358.7亿元,间接价值1990.7亿元。从不同的服务功能类型来看,其价值量大小依次为：涵养水源>固碳释氧>环境净化>提供产品>土壤保持>营养元素循环;从不同的森林类型来看,其价值量大小依次为：松柏类>灌丛>栎类>桦木类>混交林>杨树类>松杉类。但是从各种森林类型单位面积价值量来看,大小依次是：松杉类>松柏类>桦木类>混交林>栎类>杨树类>灌丛。从研究结果来看,海河流域森林生态系统服务功能价值巨大,该结果有利于加强人们对森林生态系统的认识,可以为流域生态系统管理、生态保护和生态补偿提供依据。     

济南市森林生态系统服务功能的维持机制

森林作为陆地生态系统的重要组成部分,在维持生物多样性、固碳、水源涵养和木材供应等方面起着不可替代的作用。依据《森林生态系统服务功能评估规范》(LY/T1721—2008),以济南市12个林分类型为研究对象,对济南市森林生态系统服务功能维持机制进行研究,得出济南市年森林生态系统涵养水源、保育土壤、固碳释氧、林木积累营养物质、净化大气环境、生物多样性保护的价值为251.80亿元。其中,涵养水源、固碳释氧、生物多样性保护排在前3位;不同林分类型生态系统服务功能价值量中黑杨类和柏类占绝对优势,而泡桐、落叶松和竹林生态系统服务功能较弱;不同林龄生态系统服务功能价值量以中幼龄林为主;济南市森林生态系统服务功能的维持机制,受到森林资源面积、林龄结构、森林起源以及自然保护区建设等诸多因素的影响。     

Land‐use change outweighs projected effects of changing rainfall on tree cover in sub‐Saharan Africa

Global change will likely affect savanna and forest structure and distributions, with implications for diversity within both biomes. Few studies have examined the impacts of both expected precipitation and land use changes on vegetation structure in the future, despite their likely severity. Here, we modeled tree cover in sub‐Saharan Africa, as a proxy for vegetation structure and land cover change, using climatic, edaphic, and anthropic data (R² = 0.97). Projected tree cover for the year 2070, simulated using scenarios that include climate and land use projections, generally decreased, both in forest and savanna, although the directionality of changes varied locally. The main driver of tree cover changes was land use change; the effects of precipitation change were minor by comparison. Interestingly, carbon emissions mitigation via increasing biofuels production resulted in decreases in tree cover, more severe than scenarios with more intense precipitation change, especially within savannas. Evaluation of tree cover change against protected area extent at the WWF Ecoregion scale suggested areas of high biodiversity and ecosystem services concern. Those forests most vulnerable to large decreases in tree cover were also highly protected, potentially buffering the effects of global change. Meanwhile, savannas, especially where they immediately bordered forests (e.g. West and Central Africa), were characterized by a dearth of protected areas, making them highly vulnerable. Savanna must become an explicit policy priority in the face of climate and land use change if conservation and livelihoods are to remain viable into the next century.     

Characterizing a tropical deforestation wave: a dynamic spatial analysis of a deforestation hotspot in the Colombian Amazon

Tropical deforestation is the major contemporary threat to global biodiversity, because a diminishing extent of tropical forests supports the majority of the Earth's biodiversity. Forest clearing is often spatially concentrated in regions where human land use pressures, either planned or unplanned, increase the likelihood of deforestation. However, it is not a random process, but often moves in waves originating from settled areas. We investigate the spatial dynamics of land cover change in a tropical deforestation hotspot in the Colombian Amazon. We apply a forest cover zoning approach which permitted: calculation of colonization speed; comparative spatial analysis of patterns of deforestation and regeneration; analysis of spatial patterns of mature and recently regenerated forests; and the identification of local‐level hotspots experiencing the fastest deforestation or regeneration. The colonization frontline moved at an average of 0.84 km yr^?1 from 1989 to 2002, resulting in the clearing of 3400 ha yr^?1 of forests beyond the 90% forest cover line. The dynamics of forest clearing varied across the colonization front according to the amount of forest in the landscape, but was spatially concentrated in well‐defined ‘local hotspots’ of deforestation and forest regeneration. Behind the deforestation front, the transformed landscape mosaic is composed of cropping and grazing lands interspersed with mature forest fragments and patches of recently regenerated forests. We discuss the implications of the patterns of forest loss and fragmentation for biodiversity conservation within a framework of dynamic conservation planning.     

Shadow conservation and the persistence of sacred church forests in northern Ethiopia

Land‐use change threatens biodiversity and ecosystem function worldwide. These changes have impacts on weather patterns, carbon storage, biodiversity, and other ecosystem services from regional to local scales. Only 8 percent of tropical forests are formally recognized as conservation areas, however globally, there is a network of sites that are protected because they are sacred and as a result act as ‘shadow’ conservation for biodiversity. Unlike other types of protected sites (e.g., national parks), these sites are seats of religious ritual that anchor a community's cultural identity, while also conserving biological diversity and other ecosystem services. We studied the extent and status of sacred forests in northern Ethiopia, which are threatened because of their small size (~5 ha) and isolation, increasing their exposure to edge effects and human pressures. Using historical and modern imagery, we found that over the last 50 yr, sacred forests have increased in area, but decreased in crown closure. We also found that forest ecological status, via ground‐level investigation, had high mean human disturbance (e.g., trails, plantations, exotic planting; 37%); and that forests close to markets (e.g., cities) increased in area due to planting of Eucalyptus (exotic), indicating a potential threat to their persistence and value as shelters of the church.     

大兴安岭5种典型林型森林生物碳储量

森林生态系统是陆地生态系统的重要碳库,森林生态系统的生物碳储量作为森林生态系统碳库的重要组成部分,对全球碳循环与碳平衡产生重要作用。以大兴安岭5种典型林型为研究对象,结合森林资源清查资料,采用地理信息技术(GIS),将5种林型分龄组分别对乔木层、林下的灌木层、草本层和凋落物层各组分的单位面积生物量、含碳率和生物碳储量进行测定和计量估算,并从林分水平上,采用分龄组的方法,计量估算了生物碳储量。结果表明:大兴安岭5种典型林型不同龄组的生物碳储量分别为:兴安落叶松幼龄林、中龄林、近熟林和成熟林的生物碳储量分别为15.20、50.96、95.80t/hm2和109.33t/hm2;白桦幼龄林、中龄林、近熟林和成熟林的生物碳储量分别为15.36、30.67、41.62t/hm2和64.35t/hm2;樟子松幼龄林、中龄林、近熟林和成熟林的生物碳储量分别为29.89、59.92、90.01t/hm2和117.08t/hm2;蒙古栎幼龄林、中龄林、近熟林和成熟林的生物碳储量分别为11.17、11.90、34.94t/hm2和59.49t/hm2;山杨幼龄林、中龄林、近熟林和成熟林的生物碳储量分别为21.81、28.58、42.84t/hm2和64.39t/hm2。研究发现:5种典型林型不同龄组的森林生物碳储量均随着林龄(幼龄林、中龄林、近熟林和成熟林)的增长而增加,但不同林型的碳汇功能存在差异,同一种林型在不同林龄的生物碳储量增幅差异亦较大。尤其是大兴安岭目前林分质量比较差,幼龄林和中龄林所占的比重较大,若能对现有林分加以更好地抚育和管理,该区森林植被仍具有较大的碳汇潜力,碳汇功能将进一步增强,大兴安岭在国家的生态功能区建设中将发挥更重要的碳汇功能,对此提出了森林生态系统碳增汇管理策略与管理路径。研究结果为正确认识森林生物碳储量对区域碳平衡及生态环境的影响具有重要意义,以及在未来营林、造林活动中充分发挥人工林碳汇效应提供参考依据。     

森林生态系统服务价值及其补偿校准——以马尾松林为例

森林补偿资金分配与生态系统服务脱钩,是长期以来制约森林生态保护制度发挥作用的关键因素。建立森林生态保护成效与资金分配挂钩的激励约束机制,对于完善生态补偿制度、保障国家生态安全具有重要意义。以马尾松林为例,运用野外调查、实验室实验等方法,精准计量评价马尾松林的固碳、水源涵养、固土保肥、生物多样性等4种主要生态系统服务;以皮尔(R.Pearl)生长曲线为基础构建生态补偿算法,测算基于生态系统服务价值的马尾松林补偿标准。第一,马尾松林生态系统服务价值为10335.86—16358.06元hm~(-2)a~(-1),固碳价值为165.93—521.03元hm~(-2)a~(-1),水源涵养价值为5024.47—11788.30元hm~(-2)a~(-1),固土保肥价值为3597.84—6405.04元hm~(-2)a~(-1),生物多样性价值为178.57—1346.15元hm~(-2)a~(-1)。第二,固碳价值、固土保肥价值在空间上呈现出随纬度增加而减小的格局,水源涵养价值、生物多样性价值与前两者分布格局相反。植被类型、经营方式影响马尾松林生态系统服务价值,混交林生态系统服务价值大于纯林,间伐补植的马尾松林生态系统服务价值高于皆伐后营造的林分。第三,马尾松林生态系统服务补偿标准为0.15×10~3—1.43×10~3元hm~(-2)a~(-1),大小主要受生态系统服务单价影响。本研究为森林生态系统服务精确计量评价、森林生态系统服务补偿标准的确定提供科学量化的依据。     

Multiple successional pathways in human‐modified tropical landscapes: new insights from forest succession,forest fragmentation and landscape ecology research

Old‐growth tropical forests are being extensively deforested and fragmented worldwide. Yet forest recovery through succession has led to an expansion of secondary forests in human‐modified tropical landscapes (HMTLs). Secondary forests thus emerge as a potential repository for tropical biodiversity, and also as a source of essential ecosystem functions and services in HMTLs. Such critical roles are controversial, however, as they depend on successional, landscape and socio‐economic dynamics, which can vary widely within and across landscapes and regions. Understanding the main drivers of successional pathways of disturbed tropical forests is critically needed for improving management, conservation, and restoration strategies. Here, we combine emerging knowledge from tropical forest succession, forest fragmentation and landscape ecology research to identify the main driving forces shaping successional pathways at different spatial scales. We also explore causal connections between land‐use dynamics and the level of predictability of successional pathways, and examine potential implications of such connections to determine the importance of secondary forests for biodiversity conservation in HMTLs. We show that secondary succession (SS) in tropical landscapes is a multifactorial phenomenon affected by a myriad of forces operating at multiple spatio‐temporal scales. SS is relatively fast and more predictable in recently modified landscapes and where well‐preserved biodiversity‐rich native forests are still present in the landscape. Yet the increasing variation in landscape spatial configuration and matrix heterogeneity in landscapes with intermediate levels of disturbance increases the uncertainty of successional pathways. In landscapes that have suffered extensive and intensive human disturbances, however, succession can be slow or arrested, with impoverished assemblages and reduced potential to deliver ecosystem functions and services. We conclude that: (i) succession must be examined using more comprehensive explanatory models, providing information about the forces affecting not only the presence but also the persistence of species and ecological groups, particularly of those taxa expected to be extirpated from HMTLs; (ii) SS research should integrate new aspects from forest fragmentation and landscape ecology research to address accurately the potential of secondary forests to serve as biodiversity repositories; and (iii) secondary forest stands, as a dynamic component of HMTLs, must be incorporated as key elements of conservation planning; i.e. secondary forest stands must be actively managed (e.g. using assisted forest restoration) according to conservation goals at broad spatial scales.     

National forest inventories and biodiversity monitoring in Australia

Abstract

Forests currently cover over 20% of the Australian continent and are an important resource, subject to a wide range of economic and environmental pressures. These lands support substantial numbers of forest-dependent species with national forest inventories providing important information on biodiversity. National scale information on these forests has been collected or collated since 1988 under the National Forest Inventory (NFI) programme, but substantial problems with the ‘snap shot’ approach have been recognized, particularly with respect to monitoring change and a consequent move towards a permanent and sample-based continental forest monitoring framework (CFMF) has been proposed. CFMF is proposed to consist of three Tiers: (1) satellite imagery of the continent to identify forest and change in forest cover; (2) systematic high-resolution remotely sensed data and (3) permanent ground points at 20×20 km grid interception points. The CFMF approach is in line with the international trend of national forest inventories in developed countries although the Tier 2 approach offers a useful extension. An alternative inventory approach is provided by the National Carbon Accounting System (NCAS) which models the mass of carbon and nitrogen in seven separate living and dead biomass pools for any point under forest or agriculture land use since 1970. The NCAS approach allows fine spatial and temporal monitoring of changes in these carbon and nitrogen biomass pools, and predictions of changes that result from policy or management decisions. This paper briefly reviews NFI, NCAS and the proposed CFMF, with particular emphasis on issues of use and potential for monitoring biodiversity in this biologically very diverse country.     

城市郊区小尺度森林生态系统服务功能评估

该研究以沙塘林场为例,筛选出沙塘林场森林生态系统服务功能评估指标体系,包括7项功能13个指标,并制定具体评价方法。利用广西柳州市沙塘林场2009年森林资源二类调查数据、连续观测数据和社会公共数据,采用?森林生态系统服务功能评估规范?( LY/T1721-2008),评估柳州市郊区小尺度森林生态系统服务功能的总物质量及其价值量。结果表明：沙塘林场每年每公顷涵养水源量为5051.04 m3,固土29.30 t,林分年保肥量1.09 t,固碳5.27 t,释氧11.49 t。沙塘林场森林生态系统服务功能的总价值为78077001元.a-1,每公顷提供的生态服务价值为79630元. hm-2. a-1,沙塘林场各功能项价值量从大到小顺序为涵养水源(52.02％)>固碳释氧(22.36％)>生物多样性保护(12.61％)>净化大气环境(5.06％)>保育土壤(3.84％)>森林游憩(3.09％)>积累营养物质(1.03％)。不同林分类型单位面积生态系统服务功能价值由大到小的顺序为桉类(104673.43元.hm-2.a-1)>其他阔叶林(95538.66元.hm-2.a-1)>经济林(69537.58元.hm-2.a-1)>松类(69433.52元.hm-2.a-1)>杉木类(58820.11元.hm-2.a-1)。沙塘林场单位面积涵养水源量(5051.04 m3.hm-2.a-1)大于广西区单位面积涵养水源量(3368.32m3.hm-2.a-1);沙塘林场的固碳量(5.27 t.hm-2. a-1)大于广西森林的平均固碳量(3.52 t.hm-2.a-1),森林游憩的单位面积价值量也大于广西全区的平均价值量。这说明城市郊区小尺度森林在涵养水源、固碳释氧、森林游憩等方面的生态功能价值在当地生态系统服务功能中起到关键作用。该研究结果可为城市郊区小尺度森林生态功能的评估提供理论参考,为柳州市生态文明建设提供科学依据。     

济南市森林生态系统服务功能空间格局研究

森林生态系统服务同人类福祉密不可分,日益成为全球经济的重要组成部分。依据《森林生态系统服务功能评估规范》（LY/T1721-2008）,以济南市森林生态系统为研究对象,对济南市森林生态系统服务功能进行量化评估,得出济南市年森林生态系统涵养水源、保育土壤、固碳释氧、林木积累营养物质、净化大气环境、森林防护、生物多样性保护、森林游憩的价值为264.41亿元,其中涵养水源、固碳释氧、生物多样性保护排在前3位;各区/县年森林生态系统服务功能价值量排序为：历城区 > 长清区 > 章丘市 > 平阴县 > 商河县 > 济阳县 > 市中区 > 天桥区 > 历下区 > 槐荫区;除森林防护功能以外,其他各项森林生态系统服务功能价值量的空间格局分布大体上均呈现南部 > 北部 > 中部的趋势。     

Protecting a single endangered species and meeting multiple conservation goals: an approach with Guaiacum sanctum in Yucatan Peninsula,Mexico

Aim New protected areas should consider safeguarding high conservation value sites based on multiple criteria and not just the presence of a single endangered or charismatic species. However, the extent to which complementary criteria coincide is usually unknown. We use the case of Guaiacum sanctum (Zygopyllaceae), an endangered timber tree species, to explore whether the protection of forests where this species is most abundant would meet other complementary conservation goals, such as capturing regional plant biodiversity, protecting other threatened/endemic species or safeguarding ecosystem services. Location Yucatan Peninsula, southern Mexico. Methods We conducted an analysis of the structure, composition and diversity of tree communities (including stems ≥5 cm dbh) at eight G. sanctum forest sites. We identified endemic and threatened tree species and quantified above‐ground tree biomass and carbon storage in these G. sanctum forests. Results Guaiacum sanctum forests contain 35–59 tree species on plots as small as 1000 m². The species composition of tree communities changed rapidly (high β‐diversity) across soil boundaries and rainfall regimes. Twenty‐one endemic and eight threatened tree species were recorded in our inventories. Individuals of G. sanctum represented up to 55% of the above‐ground carbon for trees ≥5 cm dbh. The high basal area of G. sanctum forests plus the high wood density, abundance, large size and longevity (more than 500 years) of G. sanctum and other tree species enhance the potential importance of these forests for carbon storage. Main conclusions A conservation strategy focused on protecting important populations of G. sanctum in the Yucatan Peninsula would have significant co‐benefits for conservation of regional tree species biodiversity and provision of critical ecosystem services. Our study illustrates a multiple criteria approach useful for the selection of areas with high conservation value on the basis of endemic, threatened species, species richness and ecosystem services.     

Soil carbon stocks,deforestation and land‐cover changes in the Western Ghats biodiversity hotspot (India)

Habitat loss and soil organic carbon (SOC) stock variations linked to land‐cover change were estimated over two decades in the most densely populated biodiversity hotspot in the world, in order to assess the possible influence of conservation practices on the protection of SOC. For a study area of 88 484 km², 70% of which lie inside the Western Ghats Biodiversity Hotspot (WGBH), land‐cover maps for two dates (1977, 1999) were built from various data sources including remote sensing images and ecological forest maps. SOC stocks were calculated from climatic parameters, altitude, physiography, rock type, soil type and land‐cover, with a modelling approach used in predictive learning and based on Multiple Additive Regression Tree. The model was trained on 361 soil profiles data, and applied to estimate SOC stocks from predictor variables using a Geographical Information System (GIS). Comparison of 1977 and 1999 land‐cover maps showed 628 km² of dense forests habitat loss (6%), corresponding to an annual deforestation rate of 0.44%. This was found consistent with other studies carried out in other parts of the WGBH, but not with FAO figures showing an increase in forest area. This could be explained by the different forest definitions used, based on ecological classification in the former, and on percentage tree cover in the latter. Unexpectedly, our results showed that despite ongoing deforestation, overall SOC stock was maintained (～0.43 Pg). But a closer examination of spatial differences showed that soil carbon losses in deforested areas were compensated by sequestration elsewhere, mainly in recent plantations and newly irrigated croplands. This suggests that more carbon sequestration in soils could be achieved in the future through appropriate wasteland management. It is also expected that increasing concerns about biodiversity loss will favour more conservation and reinforce the already prevailing protective measures, thus further maintaining C stocks.     

面向生态系统服务的森林生态系统经营:现状、挑战与展望

森林生态系统是地球陆地生态系统的主体,它具有很高的生物生产力和生物量以及丰富的生物多样性,对全球生态系统和人类经济社会发展起着至关重要和无可替代的作用。伴随着人口的不断增长和经济社会的迅猛发展,对森林资源和森林生态系统服务的需求不断高涨,而且人类对森林资源价值的认识也发生了很大程度的改变。推进森林资源可持续经营,增加森林总量、提高森林质量、增强生态功能,已成为中国林业可持续发展乃至推进中国生态文明建设和建设美丽中国的战略任务。本文全面综述了森林生态系统经营发展历程,分析了森林生态系统经营的现状和存在问题,在此基础上,提出整合基于生态系统管理与满足现代人类福祉对森林多重需求的新的森林生态系统经营理念,面向生态系统服务的森林生态系统经营理念是未来的发展趋势。森林经营发展战略表现为:1)从单纯的森林面积数量扩张,转变到提高单位面积的森林生产力和森林质量;2)从单一追求木材生产逐步转变为多目标经营,将森林林产品单一的经营目标转变为广泛的生态、经济和社会等多目标经营;3)森林经营重点从林分水平转变为森林景观的经营,强调森林景观的时空异质性和动态变化,权衡和协同多种生态系统的服务功能,倡导森林景观的多样性和连通性,提高森林与其它土地利用模式镶嵌构成的复合景观的可持续性和稳定性,增强森林生态系统对气候变化影响的适应能力;4)森林生态系统经营将从依赖传统经验的主观决策转变为信息化、数字化和智能化的决策,发展森林生态系统经营决策支持系统和森林景观恢复与空间经营规划系统。     

Natural disturbance impacts on ecosystem services and biodiversity in temperate and boreal forests

In many parts of the world forest disturbance regimes have intensified recently, and future climatic changes are expected to amplify this development further in the coming decades. These changes are increasingly challenging the main objectives of forest ecosystem management, which are to provide ecosystem services sustainably to society and maintain the biological diversity of forests. Yet a comprehensive understanding of how disturbances affect these primary goals of ecosystem management is still lacking. We conducted a global literature review on the impact of three of the most important disturbance agents (fire, wind, and bark beetles) on 13 different ecosystem services and three indicators of biodiversity in forests of the boreal, cool‐ and warm‐temperate biomes. Our objectives were to (i) synthesize the effect of natural disturbances on a wide range of possible objectives of forest management, and (ii) investigate standardized effect sizes of disturbance for selected indicators via a quantitative meta‐analysis. We screened a total of 1958 disturbance studies published between 1981 and 2013, and reviewed 478 in detail. We first investigated the overall effect of disturbances on individual ecosystem services and indicators of biodiversity by means of independence tests, and subsequently examined the effect size of disturbances on indicators of carbon storage and biodiversity by means of regression analysis. Additionally, we investigated the effect of commonly used approaches of disturbance management, i.e. salvage logging and prescribed burning. We found that disturbance impacts on ecosystem services are generally negative, an effect that was supported for all categories of ecosystem services, i.e. supporting, provisioning, regulating, and cultural services (P < 0.001). Indicators of biodiversity, i.e. species richness, habitat quality and diversity indices, on the other hand were found to be influenced positively by disturbance (P < 0.001). Our analyses thus reveal a ‘disturbance paradox’, documenting that disturbances can put ecosystem services at risk while simultaneously facilitating biodiversity. A detailed investigation of disturbance effect sizes on carbon storage and biodiversity further underlined these divergent effects of disturbance. While a disturbance event on average causes a decrease in total ecosystem carbon by 38.5% (standardized coefficient for stand‐replacing disturbance), it on average increases overall species richness by 35.6%. Disturbance‐management approaches such as salvage logging and prescribed burning were neither found significantly to mitigate negative effects on ecosystem services nor to enhance positive effects on biodiversity, and thus were not found to alleviate the disturbance paradox. Considering that climate change is expected to intensify natural disturbance regimes, our results indicate that biodiversity will generally benefit from such changes while a sustainable provisioning of ecosystem services might come increasingly under pressure. This underlines that disturbance risk and resilience require increased attention in ecosystem management in the future, and that new approaches to addressing the disturbance paradox in management are needed.     

Spatial distribution of phytomass carbon in Indian forests

A spatial analysis of phytomass carbon (C) in Indian forests for the period (1988–94) at the district‐level is reported. District‐level forest phytomass C (1988, 1994) was computed by combining remote sensing‐based forest area inventories on 1:250 000 scale, field inventories of growing stock volume by the Forest Survey of India (FSI), and crown density‐based biomass expansion factors. The estimates of forest area inventory, forest phytomass C density, and forest phytomass C pools (1988–94) were linked to the district boundary coverage of India in ARC/INFO Geographic Information System (GIS). Of the total 386 districts examined, only 17 districts had more than 75% forest cover (as percent of their geographic area) in 1988. Estimated district‐level forest phytomass C densities ranged from 4.3 to 206.8 MgC ha^?1*. At the national level, forest phytomass C pool was estimated to be 3871.2 and 3874.3 TgC# in 1988 and 1994, respectively. Although the aggregated national estimates were similar, the district‐level change analysis indicated a decrease of 77.8 TgC and an increase of 81 TgC (1988–94). The highest decrease of 10.4 TgC was observed in Vishakapatnam district (Andhra Pradesh) while largest increase of 9.8 TgC in Bastar district (Madhya Pradesh) resulting from deforestation and afforestation activities, respectively. At the national level, the total forest cover decreased by ～0.6 Mha, however, the district‐level spatial analysis indicated an increase of 1.07 Mha, and decrease of 1.65 Mha forest cover during 1988–94 period. Although, this is the first district level phytomass C analysis of Indian forests, the aggregated results at state‐level were close to the earlier estimates. The spatial analysis identified the districts that have undergone significant changes in their forest phytomass C during the study period. This improved understanding of forest phytomass C pools is important to sustainable development and conservation of forests, mitigation strategies for C sequestration, and accurate estimation of contribution of land use changes to C emission in India.     

人类活动对中国国家级自然保护区生态系统的影响

我国已建立了超过2740个自然保护区,面积约占陆地国土面积的14.8%。以我国446个国家级自然保护区作为研究对象,基于遥感信息提取、模型与方程估算、时空趋势分析,揭示2000—2015年不同类型自然保护区、自然保护区不同区域生态系统质量和关键服务的时空变化特征,利用土地覆盖变化量化人类活动并进一步分析人类正面与负面活动对生态系统质量和关键服务的影响。结果表明:(1)国家级自然保护区内土地覆盖变化表明存在不同程度的人类活动,总体表现为保护区外较保护区内剧烈,说明保护区对生态系统具有明显保护作用。(2)农田开垦、居民点修建、工矿建设、能源资源开发等人类活动对保护区生态系统的负面影响表现为草地、湿地开垦导致耕地、水库坑塘面积增加,城镇居民点与工矿建设用地扩张侵占草地。(3)湿地面积净增加而林地、草地面积净减少,反映了湿地保护、退田还湖等措施的积极作用,然而退耕还林、退牧还草局限于部分保护区;(4)气候变化是自然保护区植被覆盖度微弱上升、净初级生产力下降、生态系统水源涵养量微弱增加、土壤保持量明显增加的主要原因,而人类活动仅在局部对生态系统产生影响。为了推动我国自然保护区体系的完善和保护作用的发挥,需要统一保护区建设标准及其规范,完善保护区法律制度,积极开展相关基础科学研究。