Orchid conservation in the biodiversity hotspot of southwestern China

Xishuangbanna is on the northern margins of tropical Asia in southwestern China and has the largest area of tropical forest remaining in the country. It is in the Indo‐Burma hotspot and contains 16% of China's vascular flora in <0.2% of the country's total area (19,690 km²). Rapid expansion of monoculture crops in the last 20 years, particularly rubber, threatens this region's exceptional biodiversity. To understand the effects of land‐use change and collection on orchid species diversity and determine protection priorities, we conducted systematic field surveys, observed markets, interviewed orchid collectors, and then determined the conservation status of all orchids. We identified 426 orchid species in 115 genera in Xishuangbanna: 31% of all orchid species that occur in China. Species richness was highest at 1000–1200 m elevation. Three orchid species were assessed as possibly extinct in the wild, 15 as critically endangered, 82 as endangered, 124 as vulnerable, 186 as least concern, and 16 as data deficient. Declines over 20 years in harvested species suggested over‐collection was the major threat, and utility value (i.e., medicinal or ornamental value) was significantly related to endangerment. Expansion of rubber tree plantations was less of a threat to orchids than to other taxa because only 75 orchid species (17.6%) occurred below the 1000‐m‐elevation ceiling for rubber cultivation, and most of these (46) occurred in nature reserves. However, climate change is projected to lift this ceiling to around 1300 m by 2050, and the limited area at higher elevations reduces the potential for upslope range expansion. The Xishuangbanna Tropical Botanical Garden is committed to achieving zero plant extinctions in Xishuangbanna, and orchids are a high priority. Appropriate in and ex situ conservation strategies, including new protected areas and seed banking, have been developed for every threatened orchid species and are being implemented.     

Coupling urban 3-D information and circuit theory to advance the development of urban ecological networks

Ongoing, rapid urban growth accompanied by habitat fragmentation and loss challenges biodiversity conservation and leads to decreases in ecosystem services. Application of the concept of ecological networks in the preservation and restoration of connections among isolated patches of natural areas is a powerful conservation strategy. However, previous approaches often failed to objectively consider the impacts of complex 3-D city environments on ecological niches. We used airborne lidar-derived information on the 3-D structure of the built environment and vegetation and detailed land use and cover data to characterize habitat quality, niche diversity, and human disturbance and to predict habitat connectivity among 38 identified habitat core areas (HCAs) in Nanjing, China. We used circuit theory and Linkage Mapper to create a landscape resistance layer, simulate habitat connectivity, and identify and prioritize important corridors. We mapped 64 links by using current flow centrality to evaluate each HCA's contribution and the links that facilitate intact connectivity. Values were highest for HCA links located in the west, south, and northeast of the study area, where natural forests with complex 3-D structures predominate. Two smaller HCA areas had high centrality scores relative to their extents, which means they could act as important stepping stones in connectivity planning. The mapped pinch-point regions had narrow and fragile links among the HCAs, suggesting they require special protection. The barriers with the highest impact scores were mainly located at the HCA connections to Purple Mountain and, based on these high scores, are more likely to indicate important locations that can be restored to improve potential connections. Our novel framework allowed us to sufficiently convey spatially explicit information to identify targets for habitat restoration and potential pathways for species movement and dispersal. Such information is critical for assessing existing or potential habitats and corridors and developing strategic plans to balance habitat conservation and other land uses based on scientifically informed connectivity planning and implementation.     

Investigating the effect of landfill leachates on the characteristics of dissolved organic matter in groundwater using excitation–emission matrix fluorescence spectra coupled with fluorescence regional integration and self-organizing map

For the purpose of investigating the effect of landfill leachate on the characteristics of organic matter in groundwater, groundwater samples were collected near and in a landfill site, and dissolved organic matter (DOM) was extracted from the groundwater samples and characterized by excitation–emission matrix (EEM) fluorescence spectra combined with fluorescence regional integration (FRI) and self-organizing map (SOM). The results showed that the groundwater DOM comprised humic-, fulvic-, and protein-like substances. The concentration of humic-like matter showed no obvious variation for all groundwater except the sample collected in the landfill site. Fulvic-like substance content decreased when the groundwater was polluted by landfill leachates. There were two kinds of protein-like matter in the groundwater. One kind was bound to humic-like substances, and its content did not change along with groundwater pollution. However, the other kind was present as “free” molecules or else bound in proteins, and its concentration increased significantly when the groundwater was polluted by landfill leachates. The FRI and SOM methods both can characterize the composition and evolution of DOM in the groundwater. However, the SOM analysis can identify whether protein-like moieties was bound to humic-like matter.     

近50 a三江源地区蒸发量的变化特征及其影响因子分析

选用青海省三江源地区1964~2013年14个气象台站观测的基本气象数据,利用线性倾向性估计和Mann-Kendall检验方法等分析了三江源地区蒸发皿蒸发量的时空变化和变化趋势,并以完全相关分析方法进行蒸发量上升成因分析。结果表明:三江源地区年蒸发量总体呈显著上升趋势,其线性变化速率为30.1 mm/10 a,夏秋冬季蒸发量均呈显著上升变化,春季变化趋势不明显,夏季和秋季蒸发量上升对年蒸发量上升贡献最大;逐月蒸发量变化趋势均增加,但幅度各异;冬季蒸发量在2011年发生了突变,其余各季和年均未发生突变.蒸发量月际变化规律明显,表现为双峰型分布,双峰出现在5月和7月,最小值出现在1月;季节变化也十分明显,夏季蒸发量最大,其次为春季和秋季,冬季蒸发量最少,表明春夏两季蒸发量的多少对三江源地区水循环起重要作用。年和四季蒸发量呈现出西北部少,东南部及东北部多的分布特点,气候变化速率分布自西向东逐渐增大。蒸发量年际变化不剧烈,年蒸发量变异系数从西北向东南逐渐增大,四季蒸发量变异系数空间分布明显不同。年蒸发量与平均气温总体上呈正相关,与气温日较差、相对湿度呈负相关,平均气温上升、气温日较差和相对湿度下降是三江源地区蒸发量上升的主要因素。     

分层型水库水体好氧不产氧光合细菌时空演替特征

好氧不产氧光合细菌（aerobic anoxygenic photosynthesis bacteria,AAPB）以多样的群落结构及独特的代谢功能在水体物质循环中扮演着重要角色.基于实时荧光定量PCR及Illumina MiSeq高通量DNA测序技术研究金盆水库水体中AAPB丰度及群落结构时空演替特征,结合冗余分析揭示环境因子对其群落结构影响规律.结果表明,金盆水库水体AAPB丰度（以pufM基因计）变化范围为（6.70±0.43）×10³~（2.69±0.15）×10⁴ copies·mL^-1,最大值出现于10月,且随水深增加而减小.样本主要归为19个属（除未分类菌属外）,优势AAPB菌属包括慢生根瘤菌属（Bradyrhizobium sp.）和甲烷菌属（Methylobacterium sp.）,两者隶属α-变形菌（α-Proteobacteria）,其中慢生根瘤菌属（Bradyrhizobium sp.）占比于11月最高,高达60%以上（除10 m外）,此外也发现了以低比例存在的红长命菌属（Rubrivivax sp.）,隶属β-变形菌（β-Proteobacteria）.AAPB不同属间存在较强的互作关系,如红杆菌属（Rhodobacter sp.）与小红卵菌属（Rhodovulum sp.）呈正相关,噬氢菌属（Hydrogenophaga sp.）与慢生根瘤菌属（Bradyrhizobium sp.）呈负相关等.AAPB种群结构组成及分布差异显著,主要受T、TN、NO₃^--N和光照强度影响,且由环境因素综合调控.如10月水深0、5和15 m水体AAPB种群结构受水温（T）、总氮（TN）和总磷（TP）显著影响,12月水深5 m水体AAPB种群结构受光照强度、pH、溶解氧（DO）和叶绿素a（Chla）显著影响等.研究结果对解析分层型水库水体AAPB丰度和多样性的时空变化特征具有指导意义,并为探索AAPB种群结构的水环境驱动因素提供理论依据.     

化工码头罐区泄漏事故风险的模糊评价

泄漏是化工过程中很重要的风险事故,危险化学品的泄漏容易发生中毒或转化为火灾爆炸事故。将模糊综合评价模型应用于化工码头罐区的泄漏事故风险评价中,对重大危险源泄漏引起中毒的严重度进行排序,有助于确定安全管理工作的重心。     

黄磷尾气生产甲酸中尾气净化试验研究

通过综合研究试验筛选,研发专门适用以黄磷生产中外排废尾气为原料,匹配当今较先进的甲酸甲酯水解法(改进工艺)生产具有广泛用途和良好市场前景的环保型有机强酸———甲酸,完全满足优级甲酸生产的气体净化、提纯、提浓工艺技术,且安全可靠,经济合理。     

Historical trends in the anthropogenic heavy metal levels in the tidal flat sediments of Lianyungang, China

The sedimentation of metals can preserve the historical record of contaminant input from local and regional sources and provide information on the historical changes in regional water and sediment quality. We report the ²¹⁰Pb activities and the heavy metal (Cd, Cr, Cu, Mn, Pb and Zn) depth profiles from sediment cores retrieved in 2010. The mean sedimentation rates of 0.85-1.5 cm/yr are determined by ²¹⁰Pb dating. The sediments in the tidal flat have recorded heavy metal deposition and thus allow the establishment of a connection between the temporal evolution of the heavy metal pollution and the historical changes in the economic development of Lianyungang. The enrichment factors (EF) are calculated to estimate the level of contamination stored in these sediments. The results show that in the studied sites, Cr and Cu display low EF values and are mainly from lithogenic origin. For the other studied trace metals, a great variability in the sedimentary record is observed. Significant anthropogenic enrichment over the last 50 years is revealed at the tidal flat that receives fluvial inputs. Zinc is the element with the highest EF values, followed by the order of Pb > Cd > Mn > Cu and Cr. The temporal variations of the heavy metals peak during the late 1980s to the early 2000s and show a decreasing trend afterward. The pollution intensity of the tidal flat is determined by using EF and the geo-accumulation index (I_geo), which show that, based on the I_geo scale, the tidal flat of Haizhou Bay is unpolluted to moderately polluted.     

Influence of Chironomid Larvae on oxygen and nitrogen fluxes across the sediment-water interface (Lake Taihu, China)

The microscale distribution of oxygen,the nitrogen flux and the denitrification rates in sediment inhabited by chironomid larvae(Tanypus chinensis) were measured in eutrophic Lake Taihu,China.The presence of the chironomids in the sediment increased the oxygen diffusional flux from 10.4 ± 1.4 to 12.7 ± 2.5 mmol O 2 /(m 2 ·day).The burrows of the larvae represented "hot spots" and strongly influenced the nitrogen cycles and diagenetic activity in the sediment.The results indicate that the bioturbation effects of Tanypus chinensis chironomid larvae increased the capacity of the sediment as a sink for nitrate and a source for ammonium.Nitrate influx and ammonium outflux were increased 8.8 and 1.7 times,respectively.Under bioturbation,the amount of nitrate consumed was greater than the amount of ammonium released.The total denitrification rate was also enhanced from 0.76 ± 0.34 to 5.50 ± 1.30 mmol N/(m 2 ·day).The net effect was that the bioturbated sediments acted as a net sink for inorganic nitrogen under direct and indirect bioturbation effects compared to the control.     

Speciation of organic phosphorus in a sediment profile of Lake Taihu I: Chemical forms and their transformation

Organic phosphorus(nonreactive P,NRP)is a major component of P in sediments,but information about its chemical forms and dynamic transformation is limited.The chemical forms and dynamic behaviors of NRP in a sediment profile from Lake Taihu,a freshwater and eutrophic lake in China,were investigated.Five forms of NRP in the sediments were extracted based on a chemical fractionation technique,including easily labile NRP(NaHCO3-NRP),reactive metal oxide-bound NRP(HCl-NRP),humic acid-associated NRP(NaOH-NRPHA),fulvic acid-associated NRP(NaOH-NRPFA)and residual NRP(Res-TP).There were notable transformations with increasing sediment depth from the labile NaHCO3-NRP and NaOH-NRP pools to the recalcitrant HCl-NRP and Res-TP pools,which caused the NRP to become increasingly recalcitrant as the early diagenetic processes proceeded.Further analyses showed that the relative changes in contents of organic matter and reactive Fe oxides in the sediment profile triggered a competition for binding NRP fractions and led to the transformation of NRP.The results highlighted the importance of abiotic processes in regulating the diagenesis of organic P and its stability in sediments.