长江流域常量元素的分布特征

2003年4月到5月对长江干流及主要支流河水中常量元素（Ca ²⁺,K⁺,Na⁺,Mg²⁺,Cl^-,SO^2-₄及碱度）进行了测定,并对常量元素的含量及影响因素进行了研究。结果表明,长江阳离子以钙为主,占阳离子总量的40%~80%;而阴离子主要为HCO^-₃,占阴离子总量的60%~90%;阴阳离子含量顺序为HCO^-₃>SO^2-₄>Cl^-,Ca ²⁺>Na⁺ >Mg ²⁺>K⁺。长江干流及主要支流河水的常量离子主要来自于岩石的风化,主要受碳酸盐类溶解的控制,硅酸盐类的风化过程较弱。而大气沉降的影响很小,只有SO^2-₄受大气沉降影响较大。长江干流的Na⁺、Mg²⁺、Ca²⁺、HCO^-₃和Cl^-主要来自于上游,下游只是对上游的简单稀释,而没有额外来源。与世界上其它大河相比,长江的常量离子浓度处于较高的水平;温带地区的河流河水中常量离子的含量常处于较高的水平;热带地区的河流河水中常量离子的含量相对较低。     

长三角典型地区土壤环境中Se的空间变异特征及其与人类健康的关系

农业土壤环境中硒（Se）的缺乏或过量都会通过食物链最终影响人类健康。在203个土壤采样点的基础上,利用GIS和地统计学相结合的方法,对江苏省如皋市农田土壤环境中Se的空间变异特征及其影响因素进行分析,同时,对土壤中Se的空间分布与长寿人口的空间分布进行空间叠加分析。研究结果表明,如皋市土壤环境中总Se及水溶态Se的平均含量分别为0.13 mg/kg和2.16 μg/kg,研究区处在相对低Se的土壤环境中。总Se的空间变异性不大,其空间分布比较均一;但水溶态Se的空间变异性较大,主要受成土条件及土壤母质、土壤类型及地形地貌等结构性因子的影响。水溶态Se对土壤的理化性质也比较敏感,特别是速效磷、有机质及全钾含量与水溶态硒的相关性较显著,因此在有机质及土壤养分含量较高、土壤颗粒组成较细的东部及北部地区水溶态硒的含量也较高。土壤水溶态Se的空间分异与长寿人口比率的空间分异呈极显著的正相关关系(〖WTBX〗P〖WTBZ〗<001),相关系数达〖WTBX〗r〖WTBZ〗=0325,表明人类的健康长寿现象与环境中水溶态硒的含量有很大关系,但人类长寿的本质和真正机理仍需进一步研究验证。     

城乡交错带土地利用方式对土壤理化性质的影响

以长沙市南郊山地丘陵区为研究对象,选择7种不同土地利用方式（次生林地、经济林地、杉木人工林、采伐迹地、撂荒地、苗圃地、坡耕地）研究了城乡交错带不同土地利用方式对土壤理化性质的影响。结果表明：7种土地利用方式下,土壤颗粒组成主要集中在1～0.05 mm和＜0.001 mm两个粒级范围内,土壤质地以重壤土和轻粘土为主。随着人为干扰程度的减弱,土壤砂粒（1.0～0.05 mm）、土壤粉粒（0.05～0.01 mm）百分率逐渐下降,＜0.01 mm的土壤物理性粘粒百分率增加。自然、半自然状态利用方式的林地（次生林地、经济林地、杉木人工林地）土壤总孔隙度、含水量普遍较高,土壤密度低于坡耕地、苗圃地、撂荒地、采伐迹地,而土壤pH值、有机质含量及氮、磷、钾含量普遍高于坡耕地、苗圃地、撂荒地、采伐迹地     

外循环厌氧处理工艺中布水和三相分离的改进研究

污水处理中的布水设备和三相分离设备存在很多缺点,通过旋流配水装置和传统配水装置、小间距斜板三相分离装置和传统三相分离装置的比较试验,研究了旋流配水装置和小间距斜板三相分离装置的性能.研究结果表明:在相同膨胀率的条件下,旋流配水装置所需的回流量小,能耗相对较少;在水力上升流速为8 m/h时,采用旋流配水装置进水时,污泥分布曲线较平缓,污泥在高度上分布较均匀,而采用传统配水装置进水时,污泥主要分布在反应器底部,污泥浓度分布不均匀;在上升流速相同的情况下,采用小间距三相分离装置的反应器出水携带的颗粒污泥浓度较小;在相同的进水COD浓度时,小间距三相分离装置分离的沼气量较多.改进的布水和三相分离装置的性能明显优于传统的布水和三相分离装置.     

基于GIS与RUSLE的武陵山区小流域土壤侵蚀评价研究

以长江中下游武陵山区女儿寨小流域为研究区,基于数据观测积累及实地调查采样等方法,计算了研究区降雨侵蚀力、土壤可蚀性等因子,运用GIS与RUSLE评价了流域土壤侵蚀强度并分析了其与土地利用方式、海拔高度的关系。结果表明,流域平均土壤侵蚀强度为78844 t/（km2·a）,属微度侵蚀,流域面积9518%的范围发生轻度以下的侵蚀,强烈以上侵蚀仅占1.19%。从土地利用类型来看,耕地、果园侵蚀强度较大,均达到中度侵蚀,有林地除竹林地为轻度侵蚀外均属微度侵蚀,耕地、果园、竹林地是今后水土流失防治的主要地类。不同海拔高度中,低海拔（200～400 m）区域侵蚀量占到流域侵蚀总量的6442%,是水土流失防治的重点地带。研究为应用修正通用土壤流失方程在武陵山区进行土壤侵蚀评价提供范例,为研究区防治土壤侵蚀和流域管理规划决策提供相应参考     

Spatial Patterns of Breeding Success of Grizzly Bears Derived from Hierarchical Multistate Models

Conservation programs often manage populations indirectly through the landscapes in which they live. Empirically, linking reproductive success with landscape structure and anthropogenic change is a first step in understanding and managing the spatial mechanisms that affect reproduction, but this link is not sufficiently informed by data. Hierarchical multistate occupancy models can forge these links by estimating spatial patterns of reproductive success across landscapes. To illustrate, we surveyed the occurrence of grizzly bears (Ursus arctos) in the Canadian Rocky Mountains Alberta, Canada. We deployed camera traps for 6 weeks at 54 surveys sites in different types of land cover. We used hierarchical multistate occupancy models to estimate probability of detection, grizzly bear occupancy, and probability of reproductive success at each site. Grizzly bear occupancy varied among cover types and was greater in herbaceous alpine ecotones than in low‐elevation wetlands or mid‐elevation conifer forests. The conditional probability of reproductive success given grizzly bear occupancy was 30% (SE = 0.14). Grizzly bears with cubs had a higher probability of detection than grizzly bears without cubs, but sites were correctly classified as being occupied by breeding females 49% of the time based on raw data and thus would have been underestimated by half. Repeated surveys and multistate modeling reduced the probability of misclassifying sites occupied by breeders as unoccupied to <2%. The probability of breeding grizzly bear occupancy varied across the landscape. Those patches with highest probabilities of breeding occupancy—herbaceous alpine ecotones—were small and highly dispersed and are projected to shrink as treelines advance due to climate warming. Understanding spatial correlates in breeding distribution is a key requirement for species conservation in the face of climate change and can help identify priorities for landscape management and protection. Patrones Espaciales del Éxito Reproductivo de Osos Pardos, Derivados de Modelos Jerárquicos Multi‐Estado     

Effects of organic matter on Leymus chinensis germination,growth, and urease activity and available nitrogen in coastal saline soil

ABSTRACT

The present study was carried out to investigate the effect of three organic matters (stalk powder, microbial fertilizer, and manure) on Leymus chinensis germination, growth, and urease activity and available nitrogen (N) in coastal saline soil. The study was conducted in a completely randomized design with eight treatments: J₀V₀Y₀, J₁V₀Y₀, J₀V₁Y₀, J₀V₀Y₁, J₁V₁Y₀, J₁V₀Y₁, J₀V₁Y₁, J₁V₁Y₁. The notations were based on the quantities of each agent added to 1 kg of coastal saline soil: J₀ – no straw powder, J₁ – 0.2 kg straw powder, Y₀ – no manure, Y₁ – 0.3 kg manure, V₀ – no microbial fertilizer, V₁ – 0.2 L microbial fertilizer, each in quantic repeat. L. chinensis was sown as 50 seeds per pot. Results indicated that addition of organic agents exerted a significantly enhanced germination, increase in fresh weight and elevated soil urease activity. Soil available N levels were significantly positively correlated with soil urease activity and fresh weight, but not with germination rate. It is noteworthy that the halophyte L. chinensis showed improved characteristics when grown in coastal saline soil with addition of organic amendments.     

The Value of Using Feasibility Models in Systematic Conservation Planning to Predict Landholder Management Uptake

Understanding the social dimensions of conservation opportunity is crucial for conservation planning in multiple‐use landscapes. However, factors that influence the feasibility of implementing conservation actions, such as the history of landscape management, and landholders’ willingness to engage are often difficult or time consuming to quantify and rarely incorporated into planning. We examined how conservation agencies could reduce costs of acquiring such data by developing predictive models of management feasibility parameterized with social and biophysical factors likely to influence landholders’ decisions to engage in management. To test the utility of our best‐supported model, we developed 4 alternative investment scenarios based on different input data for conservation planning: social data only; biological data only; potential conservation opportunity derived from modeled feasibility that incurs no social data collection costs; and existing conservation opportunity derived from feasibility data that incurred collection costs. Using spatially explicit information on biodiversity values, feasibility, and management costs, we prioritized locations in southwest Australia to control an invasive predator that is detrimental to both agriculture and natural ecosystems: the red fox (Vulpes vulpes). When social data collection costs were moderate to high, the most cost‐effective investment scenario resulted from a predictive model of feasibility. Combining empirical feasibility data with biological data was more cost‐effective for prioritizing management when social data collection costs were low (<4% of the total budget). Calls for more data to inform conservation planning should take into account the costs and benefits of collecting and using social data to ensure that limited funding for conservation is spent in the most cost‐efficient and effective manner.     

基于均匀分布的滑坡数值模拟参数取值概率研究--以甘肃黑方台黄土滑坡为例

针对数值模拟参数选取主观性强、量化难度大的问题,在高精度无人机地形数据的基础上,通过对11起滑坡案例进行了407组参数反演实验,对结果准确度定量评价后,得到基于Massflow数值软件关键参数λ0的分布范围,进而运用小样本极大似然估计理论,分析区间边界长度对反演精度的影响,最终提出基于均匀分布的参数取值概率模型,并选用案例验证该模型的准确性。结果表明:地形约束会导致反演过程中所需的内聚力减小,反演获得的11组最优λ0的极差和方差分别为0.29、0.01,在置信度为95%下,极大似然法得到区间边界估计长度仅为0.0998,表明参数λ收敛性较好;反演过程中质心滑动距离ψ准确度优于堆积面积重叠率η,在λ0±0.05的范围,参数估计区间内任意值对模拟误差影响较小,评价指标ψ、η与λ0对应案例的相对误差不超过15%;所选案例验证了在置信度为95%下,以反演得到的最优参数区间边界中点构建概率分布函数的可行性和准确性,研究方法可为单体滑坡数值模拟风险评价提供理论支撑。     

Cd污染土壤的植物修复研究进展

我国农业土壤重金属污染十分严重,在所有的重金属污染中,Cd以其移动性大、毒性高成为最受关注的重金属污染之一。修复Cd污染的土壤,已成为我国农业可持续发展亟待解决的问题。与传统环境修复技术相比,植物修复技术治理成本低廉,土壤破坏力小,安全性高,是目前发展最快的环境友好、经济、高效的治理技术。介绍了Cd污染现状、超积累植物的概念和特征、土壤重金属污染植物修复国内外研究进展,并对其发展趋势进行了分析。