Dissolved organic sulfur in streams draining forested catchments in southern China

Dissolved organic sulfur (DOS) is an important fraction for sulfur mobilization in ecosystem. In this work stream waters were sampled in 25 forested sites in southern China to study the dissolved sulfur fractions. Dissolved sulfur was fractionated into dissolved organic sulfur (DOS) and inorganic sulfate (SO₄^2-) for 95 stream water samples. The results showed that the concentration of DOS ranged from 0 to 13.1 mg/L (average 1.3 mg/L) in all the streams. High concentrations of DOS in stream waters were found in the sites with high concentrations of sulfate. DOS constituted less than 60.1% of dissolved sulfur (average 17.9%). Statistical analysis showed that DOS concentration was correlated with SO₄^2- in streams waters and total sulfur in surface layer soils. The results also showed that DOS concentration in stream waters had a seasonal variation, but no trends were found with it. The implication was that the long term sulfur deposition had led the increase of the concentration and fraction of DOS in stream waters in acid rain prevailing regions     

Mega-Development Trends in the Amazon: Implications for Global Change

This paper describes four global-change phenomena that are having major impacts on Amazonian forests. The first is accelerating deforestation and logging. Despite recent government initiatives to slow forest loss, deforestation rates in Brazilian Amazonia have increased from 1.1 million ha yr^–1 in the early 1990s, to nearly 1.5 million ha yr^–1 from 1992–1994, and to more than 1.9 million ha yr^–1 from 1995–1998. Deforestation is also occurring rapidly in some other parts of the Amazon Basin, such as in Bolivia and Ecuador, while industrialized logging is increasing dramatically in the Guianas and central Amazonia.The second phenomenon is that patterns of forest loss and fragmentation are rapidly changing. In recent decades, large-scale deforestation has mainly occurred in the southern and eastern portions of the Amazon — in the Brazilian states of Pará, Maranho, Rondônia, Acre, and Mato Grosso, and in northern Bolivia. While rates of forest loss remain very high in these areas, the development of major new highways is providing direct conduits into the heart of the Amazon. If future trends follow past patterns, land-hungry settlers and loggers may largely bisect the forests of the Amazon Basin.The third phenomenon is that climatic variability is interacting with human land uses, creating additional impacts on forest ecosystems. The 1997/98 El Niño drought, for example, led to a major increase in forest burning, with wildfires raging out of control in the northern Amazonian state of Roraima and other locations. Logging operations, which create labyrinths of roads and tracks in forsts, are increasing fuel loads, desiccation and ignition sources in forest interiors. Forest fragmentation also increases fire susceptibility by creating dry, fire-prone forest edges.Finally, recent evidence suggests that intact Amazonian forests are a globally significant carbon sink, quite possibly caused by higher forest growth rates in response to increasing atmospheric CO₂ fertilization. Evidence for a carbon sink comes from long-term forest mensuration plots, from whole-forest studies of carbon flux and from investigations of atmospheric CO₂ and oxygen isotopes. Unfortunately, intact Amazonian forests are rapidly diminishing. Hence, not only is the destruction of these forests a major source of greenhouse gases, but it is reducing their intrinsic capacity to help buffer the rapid anthropogenic rise in CO₂.     

Sulphate, Nitrogen and Base Cation Budgets at 21 Forested Catchments in Canada, the United States and Europe

To assess the concern over declining base cation levels in forest soils caused by acid deposition, input-output budgets (1990s average) for sulphate (SO₄), inorganic nitrogen (NO₃-N; NH₄-N), calcium (Ca), magnesium (Mg) and potassium (K) were synthesised for 21 forested catchments from 17 regions in Canada, the United States and Europe. Trend analysis was conducted on monthly ion concentrations in deposition and runoff when more than 9 years of data were available (14 regions, 17 sites). Annual average SO₄ deposition during the 1990s ranged between 7.3 and 28.4 kg ha⁻¹ per year, and inorganic nitrogen (N) deposition was between 2.8 and 13.8 kg ha⁻¹ per year, of which 41–67% was nitrate (NO₃-N). Over the period of record, SO₄ concentration in deposition decreased in 13/14 (13 out of 14 total) regions and SO₄ in runoff decreased at 14/17 catchments. In contrast, NO₃-N concentrations in deposition decreased in only 1/14 regions, while NH₄-N concentration patterns varied; increasing at 3/14 regions and decreasing at 2/14 regions. Nitrate concentrations in runoff decreased at 4/17 catchments and increased at only 1 site, whereas runoff levels of NH₄-N increased at 5/17 catchments. Decreasing trends in deposition were also recorded for Ca, Mg, and K at many of the catchments and on an equivalent basis, accounted for up to 131% (median 22%) of the decrease in acid anion deposition. Base cation concentrations in streams generally declined over time, with significant decreases in Ca, Mg and K occurring at 8, 9 and 7 of 17 sites respectively, which accounted for up to 133% (median 48%) of the decrease in acid anion concentration. Sulphate export exceeded input at 18/21 catchments, likely due to dry deposition and/or internal sources. The majority of N in deposition (31–100%; median 94%) was retained in the catchments, although there was a tendency for greater NO₃-N leaching at sites receiving higher (<7 kg ha^-1 per year) bulk inorganic N deposition. Mass balance calculations show that export of Ca and Mg in runoff exceeds input at all 21 catchments, but K export only exceeds input at 16/21 sites. Estimates of base cation weathering were available for 18 sites. When included in the mass balance calculation, Ca, Mg and K exports exceeded inputs at 14, 10 and 2 sites respectively. Annual Ca and Mg losses represent appreciable proportions of the current exchangeable soil Ca and Mg pools, although losses at some of the sites likely occur from weathering reactions beneath the rooting zone and there is considerable uncertainty associated with mineral weathering estimates. Critical loads for sulphur (S) and N, using a critical base cation to aluminium ratio of 10 in soil solution, are currently exceeded at 7 of the 18 sites with base cation weathering estimates. Despite reductions in SO₄ and H⁺ deposition, mass balance estimates indicate that acid deposition continues to acidify soils in many regions with losses of Ca and Mg of primary concern. The U.S. Government's right to retain a non-exclusive, royalty free licence in and to any copyright is acknowledged. The Canadian Crown reserves the right to retain a non-exclusive, royalty free licence in and to any copyright.     

SOUND POLICY OR SMOKE AND MIRRORS: DOES ECOSYSTEM MANAGEMENT MAKE SENSE?1

ABSTRACT: Protection of ecosystems as entities on the landscape has attracted a wide range of support. Ecosystem-based public policies are claimed to be more effective, efficient, and scientifically sound than other approaches to environmental and natural resource policy. The ecosystem concept was never intended to serve as a public policy guide or to determine landscape units for land management purposes. This paper critically examines the use of the ecosystem concept in public policy and land use management and analyzes the proposed rule to manage the National Forest System according to ecosystem management principles. The concept is found to be unsuitable as a basis for guiding environmental and natural resource public policies in general while the proposed rule to manage the national forests according to ecosystem management principles is shown to be incoherent.     

SIMULATION OF HERBICIDE CONCENTRATIONS IN STORMFLOW FROM FORESTED WATERSHEDS1

The breakpoint rainfall hydrology and pesticide options of the field scale model CREAMS (Chemicals, Runoff, and Erosion from Agricultural Management Systems) were used to predict average concentrations of hexazinone [3 cyclohexyl-6-(dimethyl-amino)-1-methyl-1,3,5-triazine-2,4(1H,3H)-dione] in stormflow from four forested watersheds in the upper Piedmont region of Georgia. Predicted concentrations were compared with measured concentrations recorded over a 13-month period. CREAMS accurately predicted hexazinone concetrations in the initial stormflow events which also contained the highest concentrations. The model underestimated the hexazinone concentrations in stormflow two months and greater following pesticide application. In a companion study, the daily rainfall option of the CREAMS model was used to evaluate the reltive risk associated with the maximum expected concentration of hexazinone, bromacil (5-bromo-3 sec-butyl-6 methyuracil), picloram (4-amino-3,5,6 trichloropicolinic acid), dicamba (3,6-dichloro-0-anisic acid), and triclopyr {[(3,5,6-trichloro-2-pyridinyl)oxy] acetic acid} in stormflow from small forested watersheds. The model predicted the following order of potential residue appearance in stormflow: bromacil>triclopyr>hexazinone>picloram>dicamba. Subsurface movement of residues via interflow and deep leaching losses are not simulated by the version of CREAMS used in these studies.     

国有自然资源资产管理体制改革的建议与思考

自然资源产权管理和专业监管的分立可充分发挥市场作用,进一步促进简政放权,实现对山水林田湖草的综合管理,克服监管盲点,提升综合保护绩效,促进绿水青山转化为金山银山。设立专门机构开展自然资源资产管理,《生态文明体制改革总体方案》等规定了改革依据;自然资源统一确权登记试点取得积极进展,奠定了工作基础;与自然资源资产负债表、绿色GDP核算、生态文明建设目标评价考核等结合起来,促进改革的系统化和连贯化;建议在国家和省、市成立三级国有自然资源资产管理机构,在部分区域和流域派驻机构。为保障改革的实施,需界定国有自然资源资产的范围及所有权、监管权的角色和权限;改革生态补偿、排污权有偿使用、资源有偿利用等制度;明晰流域与属地的权力(利)关系;明确自然资源资产管理职责和生态环保党政同责的关系;重构环境保护税、资源税和自然资源资产使用费的关系;规定自然资源资产管理的原则、体制、制度和责任;建立自然资源资产清单、权利清单和管理信息平台;厘清各方权利边界和监管边界,建立评价考核和奖惩机制。     

The Dynamics of Species Composition and Abundance of Wasps from the Families Pompilidae, Sphecidae, and Vespidae (Hymenoptera: Aculeata) in Successional Pine Biogeocenoses of the Berezinskii Biosphere Reserve

The data on the dynamics of population size and species composition of wasps from the families Pompilidae, Sphecidae, and Vespidae were obtained in the course of long-term studies carried out in successional pine forests of the Berezinskii Biosphere Reserve. The abundance and species diversity of wasps were significantly higher in a polewood forest (40 years) than in a young forest (20 years) and mature moss forest (70 years). In an overgrown ride in the moss pine forest, the composition of dominant wasp species remained relatively stable during the seven-year period of observations, although the number of species and their abundance varied significantly from year to year, depending on the weather.     

Identifying forest ecosystem services through socio-ecological bundles: a case study from northern Jordan

This study aims to identify services provided by forest ecosystems based on locals’ perceptions in the northern part of Jordan. By better understanding preferences of locals and by understanding why they value certain services more heavily, policy-makers and planning managers can make more effective decisions regarding development and conservation. Three hundred respondents were interviewed in order to collect information about forest ecosystem services (ES). Data collection was conducted using a structured questionnaire regarding ES provided by three forest types situated in northern Jordan. ES trade-offs and socio-ecological bundles were identified by analyzing respondents’ socioeconomic demographics and preferences of forest ES through multivariate canonical corresponding analysis (CCA). The statistical analysis indicated that the socioeconomic factors and forest type have an effect on social preferences toward ES. Results displayed a clear trade-off between provisioning services and regulating and cultural services. CCA demonstrated that 73% of the variation in ES value is explained by social factors (i.e. education level, income level, and gender), while 26% of perception variation was attributable to categories of ES supplied by each forest ecosystem. These findings imply that involving people in the place-specific management of public forests using the ES approach gives managers a clearer understanding of the benefits people recognize and value, as well as those they either are not aware of or do not value. Such information is useful in forest management and in public outreach. Although direct policy applications are limited by the research’s nature, the paper provides a starting point for incorporating forest users’ voices into policy discussions and management design.     

气温变化对西南山区流域森林水文效应影响的模拟

为了揭示气温变化对西南山区流域森林水文效应的影响,用生物物理/动态植被模型SSiB4/TRIFFID与流域地形指数水文模型TOPMODEL的耦合模型SSiB4T/TRIFFID模拟了西南山区长江上游梭磨河流域森林水文效应对气温变化的响应,分析了气温变化对植被不同演替阶段的流域总径流和总蒸发以及冠层截流蒸发、植被蒸腾和土壤蒸发的影响。结果表明,（1）梭磨河流域森林（常绿针叶林）蒸腾与草和灌木差异小,森林蒸腾潜热比草和灌木仅高1~4 W.m-2,森林冠层截留蒸发高于草和灌木,但土壤蒸发明显低于草和灌木覆盖,森林覆盖流域总蒸发低于草和灌木覆盖甚至低于裸土蒸发,因此增加了流域总径流量,但森林增加径流的作用随土壤蒸发的减小而减小。（2）气温减小1℃将通过减小森林冠层截留蒸发和蒸腾而使森林增加流域总径流量的作用增加;相反,气温增加将增加森林冠层截留蒸发和蒸腾而使森林增加总径流量的作用减小。（3）当温度增加4℃,由于森林总蒸发较草和灌木明显增加,对于较高的土壤蒸发,森林增加总径流量的作用已不明显;对于较低的土壤蒸发,森林减小了流域总径流量。     

Modelling above- and below-ground mass loss and N dynamics in wooden dowels (LIDET) placed across North and Central America biomes at the decadal time scale

This article focuses on modelling above and below-ground mass loss and nitrogen (N) dynamics based on the wooden dowels (Gonystylus bancanus [Miq.] Kurz) of the decadal Long-term Intersite Decomposition Experiment (LIDET) data. These dowels were placed at 27 locations across North and Central America, involving tropical, temperate and boreal forests, grasslands, wetlands and the tundra. The dowel, inserted vertically into the soil with one half remaining exposed to the air, revealed fast mass and N losses under warm to humid conditions, and slow losses under wet as well as cold to dry conditions. The model formulation, referred to as the Wood Decomposition Model, or WDM, related these losses to (i) mean annual precipitation, mean monthly January and July air temperatures, and (ii) mean annual actual evapotranspiration (AET) at each location. The resulting calibrations conformed well to the time-in-field averages for mass remaining by location: R² = 0.83 and 0.90 for the lower and upper parts, respectively. These values dropped, respectively, to 0.41 and 0.55 for the N concentrations, and to 0.28 and 0.43 for N remaining. These reductions likely refer to error propagation and to as yet unresolved variations in N transference into and out of the wood specific to each individual dowel location. Recalibrating the model parameters by ecosystem type reduced the R² values for actual versus best-fitted mass loss by about 0.15. Doing the same without location- or ecosystem-specific adjustments reduced the R² values further, by about 0.3.