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71.
Fire is an important community wetland management tool in Indonesia, but its increasing use in the wetlands of southern Sumatra is degrading the landscape and diminishing household incomes and livelihood options. We studied evolving community land and fire use, resource and livelihood impacts on two sites of roughly 250 km2 each using satellite image analysis and biological and socio-economic surveys. Uncontrolled fire use expanded over time in relation to sonor or swamp rice cultivation, logging, fishing, grazing, and annual cropping on drained wetlands. As a result, most of the landscape has been subject to repeated fires of varying intensities, more extensive in El Niño years. Direct burning by companies played a smaller transitory role in fire ignition over the two decades. But company activities and other large-scale developments contributed to expanding community fire-based land use by bringing in more people, improving access to remote wetlands or making them more flammable. Widespread, repeated fires have transformed the landscape from mature high swamp forests to uniform stands of fire-resistant Gelam (Melaleuca cajuputi) forests and thickets, open savannas and grasslands. These new types of land cover are also degrading. Local communities have rapidly adapted to the changing resources and new opportunities. Logging and fishing declined in importance, and sonor and harvesting of Gelam expanded. But resource depletion has led to falling incomes and fewer livelihood options. The impacts extend beyond local areas as workers migrate into neighbouring forests to extract resources. Large-scale developments, community fire-based management practices and landscape transformation are spreading from accessible to formerly more remote wetlands.  相似文献   
72.
Wetlands in the Rainwater Basin in Nebraska are vulnerable to sediment accumulation from the surrounding watershed. Sediment accumulation has a negative impact on wetland quality by decreasing the depth and volume of water stored, and the plant community species composition and density growing in the wetland. The objective of this study was to determine the amount of sediment that has accumulated in five selected wetlands in the Rainwater Basin in Nebraska. Soil cores were taken at five or six locations along transects across each wetland. This study used the fly ash, which is generated by coal‐burning locomotives that were present generally in the late 1800s and early 1900s, as a marker to quantify the sediment deposition rates. The cores were divided into 5 cm sections and the soils were analyzed using a fly ash extraction and identification technique. Results indicate that the average depth of sediment ranged from 23.00 to 38.00 cm. The annual average depth of sediment accumulation ranged from 0.18 cm/yr to 0.29 cm/yr. The annual sediment accumulation rate from both wind erosion and water erosion in these five sampling wetlands was between 1.946 and 3.225 kg/m2/yr. The results of this research can be used to develop restoration plans for wetlands. The fly ash testing technology can also be applied to other areas with the railroads across the United States.  相似文献   
73.
Many species are restricted to a marginal or suboptimal fraction of their historical range due to anthropogenic impacts, making it hard to interpret their ecological preferences from modern-day data alone. However, inferring past ecological states is limited by the availability of robust data and biases in historical archives, posing a challenge for policy makers . To highlight how historical records can be used to understand the ecological requirements of threatened species and inform conservation, we investigated sperm whale (Physeter macrocephalus) distribution in the Western Indian Ocean. We assessed differences in information content and habitat suitability predictions based on whale occurrence data from Yankee whaling logs (1792–1912) and from modern cetacean surveys (1995–2020). We built maximum entropy habitat suitability models containing static (bathymetry-derived) variables to compare models comprising historical-only and modern-only data. Using both historical and modern habitat suitability predictions  we assessed marine protected area (MPA) placement by contrasting suitability in- and outside MPAs. The historical model predicted high habitat suitability in shelf and coastal regions near continents and islands, whereas the modern model predicted a less coastal distribution with high habitat suitability more restricted to areas of steep topography. The proportion of high habitat suitability inside versus outside MPAs was higher when applying the historical predictions than the modern predictions, suggesting that different marine spatial planning optimums can be reached from either data sources. Moreover, differences in relative habitat suitability predictions between eras were consistent with the historical depletion of sperm whales from coastal regions, which were easily accessed and targeted by whalers, resulting in a modern distribution limited more to steep continental margins and remote oceanic ridges. The use of historical data can provide important new insights and, through cautious interpretation, inform conservation planning and policy, for example, by identifying refugee species and regions of anticipated population recovery.  相似文献   
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Airborne particulate matter (PM) has become one of the dominant pollutants with the increasing material and energy demand due to global economic growth. The main objective of this research is to provide a comprehensive receptor level characterisation of the particulate matter collected in a city environment. Particulate matter samples were collected on Tapered Element Oscillating Microbalance (TEOM) filters from five monitoring sites over a period of 1 year. An Andersen eight-stage cascade impactor was also used to collect airborne PM samples from three other locations to compare with the samples collected by TEOM. All the samples were then subjected to individual particle morphology and chemical composition analysis by SEM/EDS. Bulk chemical composition of the samples were also analysed through ICP–OES. Based on these analyses, possible sources of the PM samples were identified. The results showed that the monitoring sites in residential environments were dominated by transportation-derived particles and other migratory particulates. Monitoring sites near the city centre were dominant by particles from transportation, with biological particles abundant for the site closer to a river. The monitoring station located close to the industrial area, despite only 200 m away from a motorway, has low contribution of non-exhaust particulates from vehicles. Instead, the particulates collected from this site were dominated by industrial sources. An air dispersion modelling package was also used to model the particulate matter dispersion in the city area for the period of sampling. The results from the model showed that the points of high emissions were around industrial areas.  相似文献   
77.
露天生物质燃烧是温室气体(CO2、CH4、N2O)的重要排放源之一,这些排放可影响本地、区域和全球的大气化学和气候变化,并带来一系列生态环境问题,进而对人类及其他生物的生存环境产生影响.本研究采用卫星火点排放清单(FINN),对2010—2019年中国露天生物质燃烧温室气体排放进行研究,并分析秸秆禁燃政策对温室气体排放的影响,对后续秸秆禁燃政策的制定具有重要参考价值.结果表明,我国2010—2019年平均年温室气体排放量为1.53×108t(将CH4和N2O的温室效应换算为同等效应的CO2当量单位),总体呈波动性下降趋势.温室气体排放量最大的植被类型是森林(7.43×107t)和农作物(3.19×107t),分别占总排放量的48.7%和20.9%.从月分布来看,露天生物质燃烧排放的温室气体集中在2—6月,3月是高峰值.从空间分布上看,排放主要集中在华南、西南和华东地区,占总排放量的72.9%...  相似文献   
78.
In the Strait of Georgia and Howe Sound, British Columbia, colonies of individual cloud sponges, growing on rock (known as sponge gardens) receive resource subsidies from the high biodiversity of epifauna on adjacent rock habitats. Bioherms are reefs of glass sponges living on layers of dead sponges. In the same area as the sponge gardens, newly discovered bioherms in Howe Sound, BC (49.34.67 N, 123.16.26 W) at depths of 28- to 35-m are constructed exclusively by Aphrocallistes vastus, the cloud sponge. The sponge gardens had much higher taxon richness than the bioherms. The sponge garden had 106 species from 10 phyla, whereas the bioherm had only 15 species from 5 phyla. For recruiting juvenile rockfish (quillback, Sebastes maliger), the food subsidy of sponge gardens appears to be missing on bioherms of cloud sponge, where biodiversity is relatively low. While adult and subadult rockfishes (S. maliger, S. ruberrimus, S. proriger, and S. elongatus) were present on bioherms, no evidence for nursery recruitment of inshore rockfishes to bioherms was observed, whereas the sponge gardens supported high densities of newly recruited S. maliger, perhaps owing to the combination of both refuge and feeding opportunities. These results indicate that sponge gardens form a habitat for early stages of inshore S. maliger, whereas A. vastus bioherms are associated only with older juvenile and adult rockfishes.  相似文献   
79.
With 2020 energy targets set out by the EU fast approaching, the UK is trying to source a higher proportion of its energy from renewable resources. Coupled with this, a growing population and increasing trends in consumer demand have resulted in national waste loads increasing. A possible solution to both issues is energy-from-waste (EfW) technologies. Many studies have focused on municipal solid waste (MSW) as a potential feedstock, but appear to overlook the potential benefits of commercial and industrial waste (C&IW). In this study, samples of C&IW were collected from three North West waste management companies and Lancaster University campus. The samples were tested for their gross and net calorific value, moisture content, ash content, volatile matter, and also elemental composition to determine their suitability in EfW systems. Intra-sample analysis showed there to be little variation between samples with the exception two samples, from waste management site 3, which showed extensive variation with regards to net calorific value, ash content, and elemental analysis. Comparisons with known fuel types revealed similarities between the sampled C&IW, MSW, and refuse derived fuel (RDF) thereby justifying its potential for use in EfW systems. Mean net calorific value (NCV) was calculated as 9.47 MJ/kg and concentrations of sulphur, nitrogen, and chlorine were found to be below 2%. Potential electrical output was calculated using the NCV of the sampled C&IW coupled with four differing energy generation technologies. Using a conventional incinerator with steam cycle, total electrical output was calculated as 24.9 GWh, based on a plant operating at 100,000 tpa. This value rose to 27.0 GWh when using an integrated gasification combined cycle. A final aspect of this study was to deduce the potential total national electrical output if all suitable C&IW were to be used in EfW systems. Using incineration coupled with a steam turbine, this was determined to be 6 TWh, 1.9% of the national demand thereby contributing 6.5% towards the UK’s 2020 renewable electricity target.  相似文献   
80.
To study potential consequences of climate-induced changes in the biotic disturbance regime at regional to national scale we integrated a model of Ips typographus (L. Scol. Col.) damages into the large-scale forest scenario model EFISCEN. A two-stage multivariate statistical meta-model was used to upscale stand level damages by bark beetles as simulated in the hybrid forest patch model PICUS v1.41. Comparing EFISCEN simulations including the new bark beetle disturbance module against a 15-year damage time series for Austria showed good agreement at province level (R2 between 0.496 and 0.802). A scenario analysis of climate change impacts on bark beetle-induced damages in Austria’s Norway spruce [Picea abies (L.) Karst.] forests resulted in a strong increase in damages (from 1.33 Mm3 a−1, period 1990–2004, to 4.46 Mm3 a−1, period 2095–2099). Studying two adaptive management strategies (species change) revealed a considerable time-lag between the start of adaptation measures and a decrease in simulated damages by bark beetles.  相似文献   
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