莲花湖库区落叶松水源涵养林土壤入渗性能的空间分布特征

以莲花湖库区落叶松水源涵养林为研究对象,由入渗速率拟合入渗模型,运用地统计学理论与方法对模型参数进行空间异质性分析。结果表明:采用Philip公式对入渗过程进行数学模拟最佳,模型参数吸渗率和稳渗率均服从对数正态分布,空间相关性强,结构比分别为0.867、0.759,变程分别为29.13 m、6.16 m,分维数分别为1.786、1.970。两者块金值都很小,小尺度内非连续性变异不明显,空间分布格局相类似,空间自相关范围内呈极显著正相关关系,相关系数R为0.48。二者相比,吸渗率空间自相关尺度大,空间分布较简单;稳渗率均一性差,空间分布复杂,破碎化程度高。     

印度洋中南部长鳍金枪鱼繁殖栖息的适应性

根据2009年3～4月在印度洋中南部水域作业的中国金枪鱼延绳钓渔船上收集数据,基于反映鱼类繁殖能力的重要指标—性腺指数(GSI)及其影响因素—表温(SST)、100 m水层的水温(TEMP)及200 m水层的溶解氧浓度(DO),对长鳍金枪鱼繁殖栖息地适应性进行分析。结果表明,表温、表层盐度、100 m水层的水温及200 m水层的DO与印度洋中南部长鳍金枪鱼GSI的最佳上界分位数回归方程分别为pGSISST0.55=159.47-12.20SST0.55+0.24SST20.55,pGSISSS0.70=527.22-28.51 SSS0.70+0.39SSS20.70,pGSITEMP0.55=2.25-0.23TEMP0.55-0.01TEMP20.55和pGSIDO0.70=53.71-17.66DO0.70+1.49DO20.70。调查区域长鳍金枪鱼繁殖栖息地指数分布在0.52～0.97之间。自北向南,繁殖栖息地指数有逐渐增加的趋势,25°S以南水域,繁殖栖息地指数基本上维持在0.65以下。本研究为阐明印度洋长鳍金枪鱼的繁殖空间分布提供了一条新的思路。     

Trace metal concentrations in hairs of three bat species from an urbanized area in Germany

Metal-contaminated soils and sediments are widespread in urbanized areas due to atmospheric deposition close to emission sources. These metals are bio-available for organisms, e.g., insects, and accumulate in food chains of insectivorous mammals. Especially bats, which live in urban regions and ingest large amounts of food relative to their body mass, are at risk of being poisoned due to the accumulation of trace metals. To determine species-specific trace metal contents in bats from urban environments, hair samples were analyzed by ICP-OES. Observed trace metal concentrations were related to species-specific foraging habitat, prey spectrum and degree of synanthropy. The species studied were Pipistrellus pipistrellus, Myotis daubentonii and Nyctalus noctula. P. pipistrellus showed the highest concentrations of lead and zinc and slightly higher concentrations of cadmium than the other two species, which was related to its high degree of synanthropy with foraging habitat mostly located in cities. In contrast, N. noctula displayed the highest contents of manganese and copper. The reason might be found in its prey spectrum, as N. noctula feeds mainly on beetles that are caught in cultured areas. Trace metal concentrations determined in hair samples of M. daubentonii ranged between the values of P. pipistrellus and N. noctula, probably reflecting an intermediate level of synanthropy. Positive correlations were observed between the concentrations of cadmium and lead and those of manganese and copper. Hair samples from bats are suitable monitoring tools to study trace metal exposure and can be used to determine differences in trace metal levels between species.     

浅水湖泊(阳澄湖)沉积物氨氧化菌的分子证据

选择长江三角洲中型浅水湖泊--阳澄湖,应用分子生物学方法鉴定淡水系统底质中的厌氧氨氧化细菌和好氧氨氧化细菌.试验设计三组厌氧氨氧化特异性巢式引物,对沉积物细菌的16S rRNA进行特异性扩增.其中,引物对AMX368f-AMX820r从底质中扩增出了anammox特异性序列,系统发育分析表明样品序列分别与Candidatus brocadia fulgida、Candidatus brocadia anammoxidans和Candidatus scalindua属近似.应用amoA基因特异性探针在底质中扩增出的好氧氨氧化菌序列,均属于Betaproteobacteria.本研究提供了阳澄湖中好氧氨氧化菌与厌氧氨氧化菌共存的分子证据.     

Spatial distribution of archaeal and bacterial ammonia oxidizers in the littoral buffer zone of a nitrogen-rich lake

The spatial distribution and diversity of archaeal and bacterial ammonia oxidizers (AOA and AOB) were evaluated targeting amoA genes in the gradient of a littoral buffer zone which has been identified as a hot spot for N cycling. Here we found high spatial heterogeneity in the nitrification rate and abundance of ammonia oxidizers in the five sampling sites. The bacterial amoA gene was numerically dominant in most of the surface soil but decreased dramatically in deep layers. Higher nitrification potentials were detected in two sites near the land/water interface at 4.4-6.1 μg NO₂^--N/(g dry weight soil·hr), while only 1.0-1.7 μg NO₂^--N/(g dry weight soil·hr) was measured at other sites. The potential nitrification rates were proportional to the amoA gene abundance for AOB, but with no significant correlation with AOA. The NH4 + concentration was the most determinative parameter for the abundance of AOB and potential nitrification rates in this study. Higher richness in the surface layer was found in the analysis of biodiversity. Phylogenetic analysis revealed that most of the bacterial amoA sequences in surface soil were affiliated with the genus of Nitrosopira while the archaeal sequences were almost equally affiliated with Candidatus ‘Nitrososphaera gargensis’ and Candidatus ‘Nitrosocaldus yellowstonii’. The spatial distribution of AOA and AOB indicated that bacteria may play a more important role in nitrification in the littoral buffer zone of a N-rich lake.     

Factors affecting the distribution of microplastics in soils of China

● Microplastic (MP) abundance in soil of China was highly heterogeneous. ● MP abundance was higher near large rivers and central land affected by monsoons. ● MP abundance was correlated with longitude, mulching film, and average temperature. ● Factors suitable for predicting MP pollution using models were discussed. Microplastics (MPs) are found worldwide in high abundance, posing a potential threat to ecosystems. Despite the ubiquity of MPs in the environment, very little is known about the regional distribution of MPs and underlying factors affecting this distribution in the field, which likely include human activity, but also features of the environment itself. Here, out of a total of 1157 datapoints investigated in 53 Chinese studies, 9.68% datapoints were removed as outliers in the heterogeneity analysis. This review revealed that the abundance of MPs was highly heterogeneous. In addition, microplastic (MP) distribution maps based on China demonstrated that the highest abundance of MPs tended to occur near large rivers and central land affected by the intersection of two monsoons. The model-fitting and previous studies showed that MP abundance in China was correlated with longitude, agricultural mulching film usage per capita, temperature, and precipitation. However, due to the heterogeneity of MPs and the low matching degree between the current environmental data and the sampling points, this pattern was not as evident as reported in any single study. Factors affecting the distribution of MPs can not be captured by linear relationships alone, and systematic selection of suitable environmental factors and further model optimization are needed to explore the cause of MP pollution in soil. Overall, this review revealed an uneven distribution of MPs and serves as a reference for model prediction to assess and control plastic pollution in natural soil environments.     

STREAM HEALTH AFTER URBANIZATION1

ABSTRACT: Urban development has compromised the quality of physical elements offish habitat in low‐order spawning and rearing streams. In order to identify where priorities should lie in stream rehabilitation, field surveys of a number of streams were conducted near Vancouver, British Columbia. All of the streams were located in watersheds which were urbanized approximately 20 years earlier. The study watersheds ranged from 5 to 77 percent total impervious area (percent TIA). The urban streambeds were found to have less fine material and slightly higher values of intragravel dissolved oxygen than in rural streams. This improved gravel quality is attributed to the higher peak flows generated by impervious areas, and the reduced recruitment of fine material in the urban watersheds. Summer base flow was uniformly low when imperviousness was above 40 percent, evidenced by a decrease in velocity rather than water depth. Large woody debris (LWD) was scarce in all streams with > 20 percent TIA. A healthy buffer zone and abundant LWD were found to stabilize stream banks. The introduction of LWD is considered the most important strategy for stream rehabilitation. Stormwater detention ponds, in contrast, are concluded to have few hydrological benefits if constructed after a stream has reached its urban equilibrium.     

Using design effects from previous cluster surveys to guide sample size calculation in emergency settings

A good estimate of the design effect is critical for calculating the most efficient sample size for cluster surveys. We reviewed the design effects for seven nutrition and health outcomes from nine population-based cluster surveys conducted in emergency settings. Most of the design effects for outcomes in children, and one-half of the design effects for crude mortality, were below two. A reassessment of mortality data from Kosovo and Badghis, Afghanistan revealed that, given the same number of clusters, changing sample size had a relatively small impact on the precision of the estimate of mortality. We concluded that, in most surveys, assuming a design effect of 1.5 for acute malnutrition in children and two or less for crude mortality would produce a more efficient sample size. In addition, enhancing the sample size in cluster surveys without increasing the number of clusters may not result in substantial improvements in precision.     

长江经济带生态系统服务权衡与协同及其驱动因素

生态系统服务及其变化是多种因素驱动的复杂过程,了解生态系统服务之间的权衡与协同作用及其驱动因素,对于实现生态系统服务有效管理和人类福祉至关重要.以长江经济带为研究区域,分析了2000~2020年产水、土壤保持、碳固定和粮食供给这4项生态系统服务的时空变化特征,运用相关性分析和地理加权回归识别和量化了生态系统服务间的权衡与协同关系,在此基础上应用偏最小二乘结构方程模型探究自然与人类活动对生态系统服务的影响,再通过地理探测器分析生态系统服务关系变化的驱动机制.结果表明:①近20年来,碳固定服务年均值由946.14 t·km^-2增至1 202.73 t·km^-2,粮食供给均值则由32.73万元·km^-2增至127.22万元·km^-2;产水和土壤保持服务增加幅度较小.②整体上,碳固定与土壤保持、粮食供给与产水为协同关系,其他生态系统服务之间为权衡关系;生态系统服务间的关系在不同地区存在一定的差异.③地形和气候是生态系统服务及多对生态系统服务权衡与协同关系的重要驱动因素,其中结构方程模型结果表明,气候对产水为正向影响（S = 0.73）,地形对粮食供给为负向影响（S = -0.57）;地理探测器结果揭示,影响碳固定与产水在空间上关系的主要驱动因子为海拔（q = 0.38）和降水（q = 0.19）.研究结果可为长江经济带生态系统服务可持续管理和实现该区域生态环境保护与社会经济的协同发展提供科学参考.     

Comparing geographic boundaries in songbird demography data with vegetation boundaries: a new approach to evaluating habitat quality

To plan for the habitat needs of forest songbirds of conservation concern, managers need to understand how spatial heterogeneity in forest conditions influences habitat quality. I used difference boundary detection (wombling) and spatially constrained clustering to delineate boundaries in various combinations of four forest vegetation variables (understory height, understory density, percent deciduous vs. conifer understory, and percent canopy closure) in two Michigan northern hardwood forests. My goal was to identify vegetation boundaries that corresponded with boundaries in an understory-dependent songbird’s distribution, and with boundaries in demographic measures for this songbird that indicate habitat quality (e.g., occupancy by older vs. yearling males, reproductive success). Both forests were actively-managed, mature stands: The first site (78 ha) was heavily deer-browsed (HB), with many browse-resistant conifers in the understory, and the second (62 ha) was less-browsed (LB), with deciduous-dominated understory. I compared the vegetation difference and cluster boundaries to difference boundaries based on 6 years of distribution and demographic data for black-throated blue warblers (Dendroica caerulescens). At the HB site, warbler boundaries overlapped strongly with vegetation boundaries that included all four variables, and clustering effectively divided the habitat into areas with different warbler occupancy and demographic characteristics. At the LB site, warbler distribution showed high overlap with difference and cluster boundaries based on just the height and density of understory vegetation, and cluster boundaries again effectively partitioned the study area into sites that varied in habitat quality. Thus, geographic boundary analysis is likely to be a useful tool for identifying key vegetation variables for management, and for delineating clusters (habitat patches) within sites that capture differences in habitat quality.