Impacts of past glaciation events on contemporary fish assemblages of the Ohio River basin

Aim We evaluated variation in fish assemblages on the basis of taxonomic composition and functional groups based on Pleistocene glacial boundaries in the Ohio River basin. We tested for the influence of habitat and hydrology on fish assemblage variation. Location Ohio River basin of North America, including the states of Ohio, Indiana and Illinois. Methods Fish collection sites were identified as Wisconsinan, pre‐Wisconsinan or unglaciated regions. Multivariate analyses, multi‐response permutation procedures, discriminant analysis and indicator species analyses were used to test whether taxonomic and functional assemblages were distinct among regions with varying glacial histories. Principal components analysis was used to identify habitat and water quality, as well as hydrological gradients that could be discerned by glacial region. Results We identified significant differences in both taxonomic and functional fish assemblage structure and habitat variation among regions that had different glaciation histories. The largest differences in taxonomic and functionally based fish communities were for unglaciated and pre‐Wisconsinan regions, while unglaciated and Wisconsinan regions were most similar. We correctly classified study regions in 71% and 60% of sites using taxonomy and functional analyses, respectively. Wisconsinan sites were characterized by Cyprinidae and Catostomidae assemblages with high abundances of tolerant fishes that tended to occur in habitats with reduced current velocity. Pre‐Wisconsinan sites were characterized by Cyprinidae, Catostomidae, Centrarchidae and Percidae families with increased abundances of intolerant fishes that tended to occur in habitats with coarser substrates and increased water velocity in streams of varying size. Unglaciated sites were characterized by Cyprinidae and Percidae families and were not closely associated with any habitat‐based functional group. Habitat in the unglaciated and pre‐Wisconsinan sites was significantly different from that in the Wisconsinan sites, which were characterized by increased channel structure and reduced stream size. Main conclusions Pleistocene glaciation events formed a lasting template of predictable regional differences in stream habitat and in the corresponding taxonomic and functional fish assemblage structures. While many factors impact the distribution of fishes, these results suggest that historical influences such as glaciation may be used to further explain the underlying mechanisms of spatial variation in fish assemblages.     

Preliminary observations on Gibbula umbilicalis (da Costa, 1778) on the Portuguese coast

Physiological indicators of nitrogen and phosphorus deficiency were used to determine the role of these nutrients in the development and proliferation of Cladophora in the Manawatu River, New Zealand. Nitrogen indicator tests showed that surplus nitrogen was available at all times. During a sustained low flow period when the dissolved reactive phosphorus was between 4–5 mg m^–3, phosphorus indicator tests revealed that the Cladophora proliferations were phosphorus deficient. A downstream trend of reduced nitrogen and phosphorus availability was also observed during this period. Sudden high river flows were frequent and had a major influence on the Cladophora biomass.     

Macroinvertebrate community in the lower Ebro river (NE Spain)

We examine the macroinvertebrate community composition and dynamics in the last 60 km of the Ebro river (NE Spain). Different sampling methods (individual stones, Surber, kick samplers and artificial substrate) were used depending on the characteristics of the sites chosen (substrate, current velocity, saline influence).The high nutrient content and the abundance of UFPOM is the origin of a high density in stones although no clear pattern exists between stone surface area and density or species richness. The high spatial heterogeneity and moderate disturbance intensity and frequency because of river regulation explains the relatively rich macroinvertebrate community and the low temporal changes in the community.     

黄河流域生态环境质量时空格局与演变趋势

黄河流域是我国重要的生态功能区，在我国经济社会发展和生态安全方面的作用举足轻重。如何及时、准确的获取黄河流域生态环境质量的时空格局与演变趋势，对黄河流域生态环境保护和建设具有重要意义。利用Google Earth Engine（GEE）平台，筛选目标年份及其前后各1年的夏季（6-9月）Landsat遥感影像，去除有云像元，掩膜水体信息，采取中值合成提取绿度、湿度、热度和干度4个生态指标，通过主成分分析快速构建遥感生态指数（RSEI）。结果表明：（1）绿度（NDVI）、湿度（Wet）、热度（LST）和干度（NDSI）4个指标在第1主成分（PC1）上的平均贡献率为89.60%，依据PC1构建遥感生态指数（RSEI）在黄河流域是可行的。（2）1990-2019年，黄河流域RSEI总体呈现出"快速变好→缓慢转好"2个阶段，1990-2000年增长趋势平均为0.005/a，增长率为11.69%，生态环境质量等级由差转为较差（10.18万km²）、较差转为中等（5.69万km²）、中等转为良（7.08万km²）贡献较大；2000-2019年增长趋势平均为0.001/a，增长率仅为3.86%，生态环境质量等级由较差转为差（6.10万km²）、良转为中等（4.09万km²）贡献较大。（3）1990-2019年，黄河流域生态环境质量提升的面积占黄河流域总面积的76.38%，其中显著提升的面积占26.14%；生态环境质量降低的面积占黄河流域总面积23.62%，其中显著降低的面积仅占1.46%。30年来黄河流域生态环境质量整体向好，实施生态工程的黄河上中游地区生态环境质量提升最快，而一些国家重点经济开发区生态环境质量有所恶化，使用GEE平台可以及时、准确的获取黄河流域生态环境质量的时空格局与演变趋势。     

‘Our bones are made of Iron’: the political ecology of Garhwali women's activism

In the Garhwal Himalaya of India's Uttarakhand State, a series of social movements emerged in the late 2000s to contest hydroelectric dams on a tributary of the sacred River Ganga. Within these opposition movements, men often took high‐profile leadership roles whereas women from a range of socio‐economic backgrounds formed the overwhelming base of participation at meetings, assemblies, and rallies. This article draws from event‐based participation and semi‐structured interviews to explore the diverse concerns that women gave to explain their engagements with opposition efforts. I counter essentialist frames and employ a feminist political ecology approach to argue that the gendered dynamics are attributable to historical, cultural, religious, and political‐economic influences. The article contributes to anthropologies of gender, environment, and social movements by taking an approach focused on disparities of practice and power that helps situate Garhwali women's roles in development contestations.     

The Role of Snowmelt and Spring Rainfall in Inorganic Nutrient Fluxes from a Large Temperate Watershed, the Androscoggin River Basin (Maine and New Hampshire)

The importance of snowmelt and spring rainfall to water and nutrient exports from macro-scale watersheds (>1000 km²) is not well established. Data collected from the Androscoggin River watershed (Maine and New Hampshire) between February 1999 and March 2002 show that the 90-day spring melt period accounted for 39–57% of total annual discharge and is likely driven both by snowpack melting and spring rainfall. While large loads of dissolved inorganic nitrogen (DIN) are delivered to the watershed from snowmelt and rain (from 1.16× 10⁶ to 1.61× 10⁶ kg N over the study years), only one third of this N load is exported from the basin during the snowmelt period (0.40× 10⁶–0.48 × 10⁶ kg N). Despite reduced residence time and temperature limitations on biological N retention, there is a poor mass balance between DIN input to the watershed and the nitrogen exported from mouth of the river. Inferences from a geochemical hydrograph separation suggests that approximately 51–63% of the water leaving the mouth of the Androscoggin river is from these ‘new’ water sources (rain and snowmelt) while 37–49% is from DIN depleted soil and groundwater. Mixing of water from different sources, as well as nutrient retention by dams in the upper watershed, may account for the large discrepancy between DIN inputs and exports from this watershed.     

基于三维生态足迹模型的长江中游城市群平衡性分析与生态补偿研究

长江中游城市群是长江经济带的重要组成部分，明晰生态足迹平衡性对城市群区域间生态补偿以及长江中游城市群生态可持续发展具有重要意义。研究采用三维生态足迹模型和基尼系数，核算长江中游城市群各市生态足迹及生态承载力，并对其生态足迹空间平衡性进行分析；同时依据三维生态足迹相关理论，计算各市生态补偿金额。结果表明：①2000-2015年长江中游城市群整体生态足迹持续上升，由65.52 hm²/人增加至139.38 hm²/人，年增长率为7.52%，武汉城市圈和襄荆宜城市群对生态足迹增长的贡献最大；②生态承载力呈下降趋势，由11.25 hm²/人减小至10.73 hm²/人，从土地利用类型来看，耕地和林地是提供生态承载能力的最主要因素；③生态足迹的综合基尼系数处于0.425-0.488之间，整体上处于"集聚程度较大"的区间范围，空间分布显示出不平衡性；④2000-2015年长江中游城市群生态补偿支付区和补偿金额持续增加，各子城市群生态补偿差异大小关系为：环鄱阳湖城市群 > 环长株潭城市群 > 武汉城市圈和襄荆宜城市群。通过分析区域生态足迹、生态承载力的时空变化特征并提出对应补偿方案，以期为长江中游城市群生态建设和管理提供决策依据。     

Regional material flow behaviors of agro‐food processing craft villages in Red River Delta,Vietnam

The economic reform “??i M?i” in 1986 has rapidly increased the number of craft villages in Vietnam, especially in the Red River Delta (RRD) leading to environmental degradation. This article presents an assessment of environmental and resource issues of agro‐Food Processing Craft Villages (FPCVs) in RRD using a refined approach to material flow analysis focusing on consistent quantification of uncertainty with particular attention to secondary and empirical data that are often faced in material flow analyses in transition economies. Material flows of agro‐Food Processing including eight types of production were examined and linked to activities of private Households, Rice Cultivation, and Pig Farming in a model called Red River Delta. Materials investigated were Goods (i.e., total materials), organic carbon (org.C), nitrogen (N), and phosphorus (P). The findings reveal material cycles are almost entirely open, that is, the materials used in FPCVs do not recycle within the region. From ～10.5 million tons/year of imported Goods used for agro‐Food Processing, final products and utilized materials account for minor fractions (～5%, by weight). Conversely, the majority (88%) is directly discharged. Materials accumulated as stocks represent 1% of Goods (100,000 tons/year), 21% of org.C (～34,000 tons/year), 42% of N (～1,300 tons/year), and 57% of P (～300 tons/year), whose substance concentrations vastly exceed natural resilience capacities. Although agro‐Food Processing accounts for negligible material shares in Red River Delta, FPCVs pollution is severe at local levels due to the location of home‐based production. Several options for closing material loops at various system scales are recommended for environmental and resource management of FPCVs. The material flow analysis results provide a database that may be used as a decision support tool for production establishments in craft villages and relevant authorities in setting priorities on environmental planning and resource management. This article met the requirements for a gold – silver JIE data openness badge described at http://jie.click/badges .     

Black liquor and the hangover effect: fish assemblage recovery dynamics following a pulse disturbance

Anthropogenic perturbations impact aquatic systems causing wide‐ranging responses, from assemblage restructuring to assemblage recovery. Previous studies indicate the duration and intensity of disturbances play a role in the dynamics of assemblage recovery. In August 2011, the Pearl River, United States, was subjected to a weak black liquor spill from a paper mill which resulted in substantial loss of fish in a large stretch of the main channel. We quantified resilience and recovery of fish assemblage structure in the impacted area following the event. We compared downstream (impacted) assemblages to upstream (unimpacted) assemblages to determine initial impacts on structure. Additionally, we incorporated historic fish collections (1988–2011) to examine impacts on assemblage structure across broad temporal scales. Based on NMDS, upstream and downstream sites generally showed similar assemblage structure across sample periods with the exception of the 2 months postdischarge, where upstream and downstream sites visually differed. Multivariate analysis of variance (PERMANOVA) indicated significant seasonal variation among samples, but found no significant interaction between impacted and unimpacted assemblages following the discharge event. However, multivariate dispersion (MVDISP) showed greater variance among assemblage structure following the discharge event. These results suggest that 2 months following the disturbance represent a time period of stochasticity in regard to assemblage structure dynamics, and this was followed by rapid recovery. We term this dynamic the “hangover effect” as it represents the time frame from the cessation of the perturbation to the assemblage's return to predisturbance conditions. The availability and proximity of tributaries and upstream refugia, which were not affected by the disturbance, as well as the rapid recovery of abiotic parameters likely played a substantial role in assemblage recovery. This study not only demonstrates rapid recovery in an aquatic system, but further demonstrates the value of continuous, long‐term, data collections which enhance our understanding of assemblage dynamics.     

Genetic structure and historical demography of Schizothorax nukiangensis (Cyprinidae) in continuous habitat

Geographic distance, different living habitats or Pleistocene climatic oscillations have frequently been found to shape population genetic structure in many species. The genetic structure of Schizothorax nukiangensis, a high altitude, valuable fish species, which is distributed throughout the Nujiang River, was investigated by mitochondrial DNA sequence analysis. The cytochrome c oxidase subunit I (COI), cytochrome b (cytb), and the mitochondrial control region (MCR) of S. nukiangensis were concatenated for examination of population structure and demographic history. The concatenated data set (2405 bp) implied a pronounced genetic population structure (overall F_ST = 0.149) and defined two population units. Strong differentiation was detected between the Sanjiangkou (SJK) population and other populations due to environmental heterogeneity, dispersal ability, and/or glacial cycles. Additional DNA sequencing of the nuclear RAG2 gene also examined significant differentiation between two units and between SJK and the upstream populations (U‐unit). Recent expansion events suggest that S. nukiangensis may have undergone a rapid increase during warm interglacial periods. Surprisingly, S. nukiangensis appears to have undergone an obvious expansion during the last glaciations (LG) for cold hardiness and a sharp contraction from 1.5 ka to the present. However, two population units exhibited different reflections during the LG, which might be closely related to their living habitats and cold hardiness. A clear pattern of isolation by distance was detected in S. nukiangensis due to feeding habits, limited dispersal ability, and/or philopatry. It is vitally important that more attention be given to S. nukiangensis due to low genetic diversity, lack of gene flow, and recent population contraction.