Three-dimensional refined modeling of water quality in Victoria Harbour

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(火用)(Exergy)在湖泊生态系统建模中的应用

基于达尔文"适者生存"理论的热力学表述,本文把热力学概念"(火用)(Exergy)"作为一些重要模型参数的目标函数引入湖泊生态动力学模型.应用拥控制下的参数组合模拟程序实现了参数随时间的变化,并通过变化的模型参数来反映湖泊生态系统中物种组成和生态结构随时间的变化.这一改进克服了以往模型刚性较强、适应性差和生态系统特性考虑少的缺陷,该改进的湖泊生态动力学模型被成功用于滇池生态系统的模拟.     

运用开放式条件估值方法评估恢复额济纳旗生态系统服务的总经济价值

条件估值方法(CVM)是当前国际上流行的衡量环境物品非利用经济价值的主要方法之一,它通过调查居民针对恢复或改善环境状况变化的支付意愿,从而定量地估计环境状况变化带来的经济效益和损失.针对黑河流域额济纳旗生态系统恶化的现状,以开放式问卷的调查方法设计了500份调查问卷,调查了黑河流域居民恢复额济纳旗生态系统的支付意愿,并采用非参数分析方法对结果进行分析.结果表明,用20年的时间将额济纳旗的生态系统恢复到80年代初的水平,黑河流域总共有93.2%的居民家庭存在支付意愿,有支付意愿家庭的平均支付意愿为每年每户44.9元,同时采用列联表检验的方法辨明了被调查者的年龄、学历、收入、户籍和居住的地理区域等因素对支付意愿的影响.最后在综合不同区域居民支付意愿差异的基础上,采用当前的市场利率将计算结果在时空尺度上加总,得到恢复黑河下游额济纳生态系统的总经济价值的现值为1.224×10⁸元.     

退水期鄱阳湖薹草(Carex cinerascens)和藜蒿(Artemisia selengensis)洲滩湿地CO2通量变化及其影响因子

于2014年10月到2015年5月鄱阳湖退水期,利用密闭箱—气相色谱法对鄱阳湖北部星子县洲滩两种代表性的植被群落——薹草(Carex cinerascens)和藜蒿(Artemisia selengensis)进行CO_2通量的对比观测,结果表明:薹草和藜蒿湿地的生态系统呼吸具有明显季节变化模式,其最小值均出现在冬季,最大值均出现在春季,平均值分别为3291.80和2581.89mg CO_2/(m~2·h),退水期薹草和藜蒿湿地累积的CO_2通量分别为213.71±2.27和176.39±11.48 t CO_2/hm~2.较高的生物量是薹草湿地CO_2通量高于藜蒿湿地的原因.5 cm土温是影响薹草和藜蒿湿地CO_2通量季节变化最重要的影响因子,藜蒿湿地生态系统呼吸的温度敏感性指数(Q10)高于薹草湿地.水分、植物生物量和湿地CO_2通量之间无显著相关性.     

A seismic monitoring approach to detect and quantify river sediment mobilization by steelhead redd-building activity

The role of spawning salmonids in altering river bed morphology and sediment transport is significant, yet poorly understood. This is due, in large part, to limitations in monitoring the redd-building process in a continuous and spatially extended way. A complementary approach may be provided through the use of a small seismic sensor network analysing the ground motion signals generated by the agitation of sediment during the redd-building process. We successfully tested the viability of this approach by detecting and locating artificially generated redd signals in a reach of the Mashel River, Washington State, USA. We then utilize records of 17 seismic stations, in which we automatically detected seismic events that were subsequently manually checked, yielding a catalogue of 45 potential redd-building events. Such redd-building events typically lasted between 1 and 20 min and consisted of a series of clusters of 50–100 short energetic pulses in the 20–60 Hz frequency range. The majority (>90%) of these redd-building events occurred within 11 days, predominantly during the early morning and late afternoon. The seismically derived locations of the signals were in agreement with independently mapped redds. Improved network geometry and installation conditions are required for more efficient detection, robust location and improved energetic insights into redd-building processes in larger reaches. The passive and continuous nature of the seismic approach in detecting redds and describing fish behaviour provides a novel tool for fish biologists and fisheries managers, but also for fluvial geomorphologists, interested in quantifying the amount of sediment mobilized by this ecosystem engineer. When complemented with classic approaches, it could allow for a more holistic picture of the kinetics and temporal patterns (at scales from seconds to multiple seasons) of a key phase of salmonid life cycles. © 2020 The Authors. Earth Surface Processes and Landforms published by John Wiley & Sons Ltd     

The decomposition rate of the organic carbon content of suspended particulate matter in the tropical seagrass meadows

In terms of downward transport, suspended particulate matter(SPM) from marine or terrigenous sources is an essential contributor to the carbon cycle. Within mesoscale environments such as seagrass ecosystems, SPM flux is an essential part of the total carbon budget that is transported within the ecosystem. By assessing the total SPM transport from water column to sediment, potential carbon burial can be estimated. However, SPM may decompose or reforming aggregate during transport, so estimating the vertical flux without knowing the decomposition rate will lead to over-or underestimation of the total carbon budget. Here this paper presents the potential decomposition rate of the SPM in seagrass ecosystems in an attempt to elucidate the carbon dynamics of SPM. SPM was collected from the seagrass ecosystems located at Sikka and Sorong in Indonesia. In situ experiments using SPM traps were conducted to assess the vertical downward flux and decomposition rate of SPM. The isotopic profile of SPM was measured together with organic carbon and total nitrogen content. The results show that SPM was transported to the bottom of the seagrass ecosystem at a rate of up to(129.45±53.79)mg/(m~2·h)(according to carbon). Considering the whole period of inundation of seagrass meadows, SPM downward flux reached a maximum of 3 096 mg/(m~2·d)(according to carbon). The decomposition rate was estimated at from 5.9 μg/(mg·d)(according to carbon) to 26.6 μg/(mg·d)(according to carbon). Considering the total downward flux of SPM in the study site, the maximum decomposed SPM was estimated 39.9 mg/(m~2·d)(according to carbon) and 82.6 mg/(m~2·d)(according to carbon) for study site at Sorong and Sikka, respectively.The decomposed SPM can be 0.6%–2.7% of the total SPM flux, indicating that it is a small proportion of the total flux. The seagrass ecosystems of Sorong and Sikka SPM show an autochthonous tendency with the primary composition of marine-end materials.     

太湖流域湖荡湿地生态系统健康评价

太湖流域湖荡湿地影响着整个流域生态系统的健康运转,是湖泊水体与陆地之间的过渡带,对周边城市的生态环境起到重要的净化调节作用,对太湖流域湖荡湿地生态系统健康进行评价,有利于湖荡湿地的科学管理,从而实现湖荡湿地资源的可持续利用.本文选择太湖流域11个典型的湖荡湿地为研究对象,于2012-2015年开展周年湿地观测季度调查.利用主客观组合赋权方法,结合太湖流域自然条件和社会功能,提出了基于生态可修复性指标的太湖流域湖荡湿地生态系统健康评价体系和方法.结果表明：太湖流域湖荡湿地中生态系统健康等级为优的占27.27%,分别是傀儡湖、尚湖和钱资荡;生态系统健康等级为良的湖荡湿地占9.09%,为长荡湖;中等生态系统健康水平的湖荡湿地居多,占36.36%,分别是阳澄湖、昆承湖、元荡和淀山湖;生态系统健康等级为差的湖荡湿地占18.18%,分别是滆湖、澄湖和宜兴三氿.本研究建立的湖泊生态健康评估体系和湖泊生态健康评价结果对太湖流域湖荡湿地的后续有效管理具有重要的现实意义.     

Understanding the spatial distribution and physical attributes of upland swamps in the Sydney Basin as a template for their conservation and management

Temperate Highland Peat Swamps on Sandstone (THPSS) and Coastal Upland Swamps in the Sydney Basin (CUSSB) are listed as endangered ecological communities under Australia's national and state legislation. They are threatened by a range of human and climate impacts. Across the region there are 3208 individual, valley-bottom, elongate-shaped, upland swamps that drain first- or second-order drainage lines and small catchment areas (mean?=?0.25?km²). They occur at a median distance of 57?km from the coast in areas with an average annual rainfall of 1505?mm/year and average annual temperature of 15°C. Those closer to the coast occur on elevations as low as 160?m a.s.l., and those further from the coast, on plateau country, occur up to 1172?m a.s.l. (median 634?m a.s.l.). The valleys that contain these swamps terminate downstream at a valley constriction or bedrock step, behind which alluvial materials have accumulated, and peat has formed to produce relatively steep swamps (median slope 6.2 per cent). Understanding the spatial distribution and physical attributes of these systems, and having the accompanying maps as a resource, is critical for development of sound, well-informed conservation, rehabilitation and monitoring programs, and for analysing the ecosystem services they provide.     

Reindeer Herders Without Reindeer. The Challenges of Joint Knowledge Production on Kolguev Island in the Russian Arctic

Kolguev Island in the Russian Arctic has a unique tundra ecosystem and an indigenous Nenets population whose livelihood is traditionally based on reindeer herding. The Nenets faced a major crisis in 2013–2014 when the reindeer population collapsed. Widely different explanations for this collapse were put forward. This lack of a shared perspective points at the failure of genuine joint knowledge production (JKP) in the island’s UNEP–GEF’s ECORA project (2004–2009). The ECORA project aimed to achieve integrated ecosystem management by stimulating dialog and mutual learning among indigenous people, state agencies, and scientists. This paper analyses the failure of ECORA’s JKP, using a recently developed framework of conditions for successful JKP. The results suggest that ECORA met none of these conditions. It failed at bringing the scientific and indigenous knowledge systems together, and the produced knowledge did not resonate with indigenous people’s perception of living in Kolguev.     

中美港湾流域生态系统服务价值变化比较——以浙江象山港与佛罗里达坦帕湾为例

人类活动干扰下的生态系统服务价值变化的国别或区域差异与对比研究成果,可为海岸带综合管理和相关空间规划提供有效指引。以Landsat TM/OLI遥感影像为基础数据,运用GIS空间分析手段,对人类活动影响下的中美两个港湾生态系统服务价值时空变化格局进行了研究。结果表明：① 近30年来象山港流域生态系统类型以农田和森林为主,而坦帕湾流域则以城市和森林为主,两港湾非自然生态系统类型面积大于自然生态系统类型,是研究区生态格局分异的主要影响原因。② 随着人类活动强度增加与开发利用范围扩大,研究时段内象山港流域生态系统服务价值减少了397.64×10⁶元,而坦帕湾减少了1186.73×10⁶元。③ 两港湾流域生态系统服务价值空间分布与区域经济发展水平呈负相关,其中交通布局、农业生产、都市发展等因素对生态系统服务价值分布影响显著。④ 90年代以来坦帕湾海洋功能区划与滨海开发建设过程中遵循自然规律,尤其是“坦帕湾河口保护计划”的管理经验可供象山港开发利用借鉴,象山港需要细化符合其开发的管护方案与多规合一规划,加以启示国内相同级别港湾管理、增强邻里计划与合作交流。