Monitoring a Recent Delta Formation in a Tropical Coastal Wetland Using Remote Sensing and GIS. Case Study: Guapo River Delta, Laguna de Tacarigua, Venezuela

The integrated use of remotely sensed data and GIS to monitor a rapid recent delta formation was undertaken in the Tacarigua Lagoon, a mangrove coastal protected wetland in the north-central coast of Venezuela. Recently, the resource value of coastal wetlands such as coastal lagoons and deltas, has brought about a need to protect and conserve these ecosystems. To that end, valuable resources such as these should be continuously monitored so that temporal changes in their environment can be analysed. The importance of determining the cause, extent, and spatial distribution of these changes can then be used in different aspects of environmental studies, land suitability analyses and for wise resource management. Aerospace data interpretation and a field survey were utilised to study the formation of the Guapo River delta within the Tacarigua Lagoon and to map the expansion that this depositional environment has undergone. A historical set of aerial photographs and a radar image, together with a GIS, were used to assess the growth of the delta from the beginning of its formation up to the present time.     

HYDROLOGIC EFFECTS OF CLEARCUTTING AND STRIPCUTTING LOBLOLLY PINE IN THE COASTAL PLAIN1

ABSTRACT: Harvesting 29-year-old loblolly pine (Pinus taeda L.) plantations on six small catchments in the Coastal Plain of west Tennessee caused variable but generally minor increases of storm-flow volumes during the four years following harvest. The increases were primarily associated with decreases of rainfall interception rather than with soil disturbance. Harvesting had no effect on stormflow volumes in six nearby catchments of 37-year-old loblolly pine to which the same treatments were applied. Postharvest increases of flow-weighted sediment concentrations averaged higher for the catchments with greater flows at both locations. During the fourth through eighth years after harvest, average sediment concentrations for harvested catchments at each location approximated closely the base rate of 62 mg L^-1 previously defined for undisturbed pine types. Thus, relatively minor postharvest increases of stormflow volumes in the six 29-year-old plantations and increases of sediment concentrations in all 12 catchments were limited to about four years. Nevertheless, because of potential channel erosion, the findings confirm the need to extend stream management zones well up into drainages with intermittent and ephemeral flows wherever water quality is a concern. Despite certain undesirable effects of logging (baring of mineral soil, decreased weight and depth of forest floor, increased soil bulk density), the results demonstrate the high resilience developed by pine planted on severely eroded sites in the southern Coastal Plain.     

Fluxes of CH4 and N2O from soil under a tropical seasonal rain forest in Xishuangbanna, Southwest China

CH4 and N2O fluxes from soil under a tropical seasonal rain forest in Xishuangbanna, Southwest China were measured for one year using closed static chamber technique and gas chromatography method. Three treatments were set in the studied field: (A) litter-free,(B) with litter, and (C) with litter and seedling. The results showed that the soil in our study was a sink of atmospheric CH4 and source of atmospheric N2O. The observed mean CH4 fluxes from treatments A, B, and C were -50.0±4.0, -35.9±2.8,-31.6±2.8 μgC/(m2·h),respectively,and calculated annual fluxes in2003 were -4.1,-3.1,and -2.9kgC/hm2,respectively.The observed mean N2O fluxes from treatments A,B,and C were 30.9±3.1,28.2±3.5,50.2±3.7μgN/(m2·h),respectively,and calculated annual fluxes in 2003 were 2.8, 2.6, and 3.7 kgN/hm2, respectively. Seasonal variations in CH4 and N2O fluxes were significant among all the three treatments. The presence of litter decreased CH4 uptake during wet season (P ＜ 0.05), but not during dry season. There was a similar increase in seedlings-mediated N2O emissions during wet and dry seasons, indicating that seedlings increased N2O emission in both seasons. A strong positive relationship existed between CH4 fluxes and soil moisture for all the three treatments, and weak relationship between CH4 fluxes and soil temperature for treatment B and treatment C. The N2O fluxes correlated with soil temperature for all the three treatments.     

Modeling effects of temperature and precipitation on carbon characteristics and GHGs emissions in Abies fabric forest of subalpine

Abies fabric forest in the eastern slope of Gongga mountain is one type of subalpine dark coniferous forests of southwestern China. It is located on the southeastern edge of the Qinghai-Tibet plateau and is sensitive to climatic changes. A process-oriented biogeochemical model, Forest-DNDC, was applied to simulate the e ects of climatic factors, temperature and precipitation changes on carbon characteristics, and greenhouse gases (GHGs) emissions in A. fabric forest. Validation indicated that the Forest-DNDC could be used to predict carbon characteristics and GHGs emissions with reasonable accuracy. The model simulated carbon fluxes, soil carbon dynamics, soil CO2, N2O, and NO emissions with the changes of temperature and precipitation conditions. The results showed that with variation in the baseline temperature from –2℃ to +2℃, the gross primary production (GPP) and soil organic carbon (SOC) increased, and the net primary production (NPP) and net ecosystem production (NEP) decreased because of higher respiration rate. With increasing baseline precipitation the GPP and NPP increased slightly, and the NEP and SOC showed decreasing trend. Soil CO2 emissions increased with the increase of temperature, and CO2 emissions changed little with increased baseline precipitation. With increased temperature and decreased baseline temperature, the total annual soil N2O emissions increased.With the variation of baseline temperature from –2℃ to +2℃, the total annual soil NO emissions increased. The total annual N2O and NO emissions showed increasing trends with the increase of precipitation. The biogeochemical simulation of the typical forest indicated that temperature changes strongly a ected carbon fluxes, soil carbon dynamics, and soil GHGs emissions. The precipitation was not a principal factor a ecting carbon fluxes, soil carbon dynamics, and soil CO2 emissions, but changes in precipitation could exert strong e ect on soil N2O and NO emissions.     

壶瓶山国家级自然保护区森林生态旅游开发前景

森林是世界上最大的陆地生态系统,森林生态旅游必将是绿色旅游的主体。壶瓶山国家级自然保护区是中国40个具有国际意义（A级）的自然保护区和具有全球意义的17个生物多样性关键地区之一,其旅游资源十分丰富,是开展森林生态旅游的理想之地。阐述了森林生态旅游的内涵和开发意义,从区位优势和资源优势两个方面对壶瓶山国家级自然保护区发展森林生态旅游的可行性进行了研究,在此基础上,对自然保护区森林生态旅游开发提出了对策和建议,认为壶瓶山国家级自然保护区森林生态旅游具有广阔的开发前景。     

“最小存活种群”和“种群生存力分析”理论在生物多样性评价中的应用——以黔北20万吨/年竹浆林一体化工程中原料林基地建设工程为例

概述了“最小存活种群”和“种群生存力分析”概念、产生过程、研究内容及在生物多样性保护中的应用步骤,并运用该理论,以敏感种豹为关键种,分析了黔北新建20万吨/年竹浆林一体化工程中原料林基地建设工程对拟建项目区生物多样性的影响。分析结果表明,如原料林基地远离豹的栖息地,则栖息地面积尚可满足对豹短期保护（50代）的要求。因此,原料林基地的建设对绝大多数野生动物的影响不大,项目区的生物多样性是可以维持的。     

盐城市沿海的适宜开发空间选择研究

开发空间选择通过辨识适宜开发空间,使得工业发展、城市建设活动尽可能地配置在弱自然生态阻力、强经济引力的空间,实现区域生态、经济效益的最大化。借鉴以往研究,结合案例区特点,建立指标体系,基于乡镇单元,运用GIS工具综合分析盐城市域自然生态阻力和经济引力的空间分异特征,运用矩阵列联分类方法划分空间开发适宜类型,并根据适宜开发空间的地域特点将其分为城市区域和临港区域。研究认为,盐城沿海的适宜开发空间主要分布于204国道沿线的县市城区、部分临近乡镇及沿海陈家港、滨海港、海通镇等地区;临海部分乡镇凭借其资源潜力宜作为临港区域,是未来的主要产业空间载体;其它地区应定位于城市化空间,未来建设用地指标应优先向这些区域投放,引导人口、产业向这些地区的集聚。     

官渡区城市森林建设实践与生态效益分析

介绍了官渡区城市森林建设实践,分析了官渡区城市森林综合效益,并提出了提高官渡区城市森林效益的措施。     

Distribution of mercury in di erent environmental compartments in the aquatic ecosystem of the coastal zone of the Southern Baltic Sea

The aim of this study was to characterize mercury (Hg) contamination in the coastal waters of the Southern Baltic Sea, and to investigate transformations of Hg in the initial links of the marine food chain. Concentrations of Hg in water, particulate matter, plankton and macrophytes at various stations in the coastal zone (a bay with restricted water exchange, near an industrial city, river mouths, and the open sea) were measured in 2006–2008. Hg concentrations observed in the Southern Baltic varied greatly, showing the highest average values in all environmental compartments near the river mouths. In shallow, sheltered parts of the gulf, where water exchange is restricted, Hg concentrations in the water and in macrophytes were elevated relative to those in the coastal zone of the deeper part of the bay and in the open Baltic. Distance to the river mouth, terrestrial runo , and quantity and quality of organic matter were more important than seasonal variations in controlling Hg and HgSPM concentrations in water samples. Mercury concentrations in the surface microlayer at the air/sea interface were over 10 times higher than those in the bulk surface water. Concentrations of Hg in macrophytes in the winter were significantly higher than those in the warm seasons (spring, summer, autumn). This was probably the combined e ect of higher availability of Hg in porewaters and leaf growth inhibition.     

九龙江流域森林生态修复模式建立与评价

通过对九龙江上游流域森林生态环境现状调查分析,表明：九龙江上游流域森林生态系统仍然脆弱,森林结构不舍理,林种、树种、龄级结构比例失调;林分总体质量下降,并严重导致为空间分布不均衡的破碎性和单一性的残次林;森林资源管护机制不落实,环境污染和“青山挂白”急待绿化整治。按照“绿、亮、美”要求和以人为本的原则,建立了适宜九龙江上游流域森林生态修复模式,并对实施效果进行评价。