镇江长江豚类省级自然保护区水域生态修复效果的监测与评价

自2006年以来,长江豚类极度濒危的生存状况得到广泛关注,在其自然保护区实施一系列生态修复工程,为镇江长江豚类省级自然保护区内的江豚提供良好的生存环境。于2015—2018年在和畅洲水域建设生态浮岛、人工鱼巢和放流底栖动物进行水域生态修复,对生态修复工程进行跟踪监测和效果评价。结果表明：生态浮岛的建设可提高区域内浮游植物和浮游动物的生物多样性和群落结构复杂程度;人工鱼巢对产黏性卵鱼类具有一定增殖效果,增殖种类主要为鲤、鲫、䱗和黄尾鲴;生态浮岛和人工鱼巢的建设对鱼类均有较好的聚集效果;底栖动物增殖放流显著增加了放流物种的丰度、生物量及保护区底栖动物群落生物量,增殖放流效果评价为中等。该自然保护区水域生态修复效果明显,为工程施工影响下水生生物保护区生态修复提供科学依据。     

不同乳酸菌组合对苜蓿青贮细菌群落结构的影响

为探讨不同乳酸菌互作对苜蓿（Medicago sativa）青贮细菌群落结构的影响，以2种植物乳杆菌、乳酸片球菌、戊糖片球菌及凝结芽孢杆菌形成的6种乳酸菌组合按1.5 mL·kg^-1的添加量制作苜蓿青贮，以等量蒸馏水替代添加剂作为对照，45 d后运用高通量测序分析细菌群落结构。结果表明，各苜蓿青贮的优势乳酸菌群均为厚壁菌门（Firmicates）的乳杆菌属（Lactobacillus）和片球菌属（Pediococcus），二者相对丰度之和为65.4%~79.0%，其中含植物乳杆菌处理高于对照和含凝结芽孢杆菌处理；与对照相比，乳酸菌组合处理提高了菌群Chao1和ACE指数但降低了Simpson和Shannon指数；6个乳酸菌组合处理中，含凝结芽孢杆菌处理组与对照相似性较高，对苜蓿青贮细菌群落影响较小；相关分析表明，苜蓿青贮菌群结构和多样性可较好地解释其营养品质的变化。综上，乳酸菌组合在一定程度上改善了苜蓿青贮的细菌群落结构，其中含植物乳杆菌的组合效果较好。     

Tracing regime influence on urban community gardening: How resource dependence causes barriers to garden longer term sustainability

This article explores how resource dependence leads to barriers to urban community gardening. Nine barriers to urban gardening were identified: finance, space, organizational structure, water, external damage, soil, communication, interpersonal issues, and participation issues. Using process tracing and grounded theory, we found that these barriers could be divided into three groups: primary, secondary, and participation barriers. Primary barriers are caused and directly influenced by the regime, whereas secondary barriers are the result of decisions and actions taken while addressing the primary barriers. All of these barriers cause frustration and affects the ability of the gardens to retain and acquire new members. This affects the longer term sustainability of the gardens and their potential to contribute to an urban governance transition.     

Substrate composition determines emergence success and development of European nase larvae (Chondrostoma nasus L.)

European nase (Chondrostoma nasus) is a specialist riverine fish, characterised by a complex life cycle making it vulnerable to habitat degradation. Recent findings indicate that, analogously to salmonids, the interstitial zone quality may pose a serious bottleneck for successful recruitment of this species. In this study, nase eggs were exposed to different substrate qualities. First, standardised substrate mixtures with differing fine sediment additions were used. Second, we tested different homogenous gravel fractions for their influence on egg development and emergence success. In both setups, substrate composition significantly affected emergence success, timing of emergence and larvae size at emergence. In the substrate mixtures, emergence was most successful in substratum with no fine sediment addition (98%) and decreased to 55% in substratum with 20% fine sediment addition. Emergence was most successful in the coarsest fraction (93%) and decreased to 47% in the finest fraction. Over all treatments, the time between hatching and emergence from substrate differed by up to 156 degree days, thereby indicating that free embryos of nase use the shelter of the interstitial zone for early ontogeny. These results suggest that a loose and porous stream bed can positively contribute to the development success of eggs and larvae and thereby potentially improve the recruitment of nase populations. It is thus important to consider the substrate and interstitial conditions in the conservation and restoration management of this rheophilic cyprinid.     

Responses of plant community to the linkages in plant-soil C:N:P stoichiometry during secondary succession of abandoned farmlands,China

Succession is one of the central themes of ecology;however,the relationship between aboveground plant communities and underground soils during secondary succession remains unclear.In this study,we investigated the composition of plant community,plant-soil C:N:P stoichiometry and their relationships during secondary succession after the abandonment of farmlands for 0,10,20,30,40 and 50 a in China,2016.Results showed that the composition of plant communities was most diverse in the farmlands after secondary succession for 20 and 50 a.Soil organic carbon and total nitrogen contents slightly decreased after secondary succession for 30 a,but both were significantly higher than those of control farmland(31.21%-139.10%and 24.24%-121.21%,respectively).Moreover,C:N ratios of soil and microbe greatly contributed to the changes in plant community composition during secondary succession of abandoned farmlands,explaining 35.70%of the total variation.Particularly,soil C:N ratio was significantly and positively related with the Shannon-Wiener index.This study provides the evidence of synchronous evolution between plant community and soil during secondary succession and C:N ratio is an important linkage between them.     

生态文明视域下草原治理体系构建研究

草原是我国面积最大的陆地生态系统，既是我国重要的生态安全屏障，也是广大农牧民赖以生存的家园。为深入贯彻习近平生态文明思想，落实山水林田湖草沙系统治理的理念，推进草原保护修复和高效利用，本研究结合"十四五"林业和草原保护发展规划纲要，提出了构建草原监测评价体系、草原保护体系、草原生态修复体系、草原执法监管体系、现代草业体系、支撑保障体系等草原治理体系，旨在为推进草原治理体系和治理能力现代化提供参考。     

基于实地和遥感调查的离子型轻稀土尾砂土壤侵蚀对植被修复措施响应

稀土开采产生大量尾砂,导致严重土壤侵蚀,伴生水质和地质灾害,评价植被修复措施对稀土尾砂土壤侵蚀治理效果可为措施优选提供理论依据。以寻乌县离子型轻稀土尾砂区为研究区,基于1982—2015年GIMMS NDVI 3 g、DEM等遥感和尾砂理化性状现场调查数据,采用空间代时间方法,结合RUSLE模型及其全微分公式探究不同修复年限土壤侵蚀量对植被修复措施的响应机理。结果表明:1982—2015年研究区土壤侵蚀模数显著下降,倾向率为-60 t/(km~2·10a),突变年份为2008年;在植被修复措施实施年(2008年)前后,多年平均土壤侵蚀量减幅超过60%;土壤侵蚀模数呈现上升、平稳、上升、平稳、上升和下降的阶段性变化,与NDVI时程变化呈负相关;水土保持措施、植被覆盖、土壤可蚀性和降雨变化对土壤侵蚀量减小的贡献率分别为33.18%,32.19%,19.95%,13.19%。植被修复过程中,矿区土壤侵蚀量减少的主要影响因子为水土保持措施因子和植被覆盖因子。     

黄河口生态恢复工程对湿地土壤不同形态无机硫动态变化的影响

选择黄河口生态恢复前后的未恢复区（R₀）、2007年恢复区（R₂₀₀₇）和2002年恢复区（R₂₀₀₂）的芦苇湿地为研究对象，探讨了生态恢复工程对生长季湿地土壤无机硫形态变化的影响。结果表明，生态恢复工程不同程度地改变了湿地土壤中各形态无机硫含量。相对于R₀，R₂₀₀₂和R₂₀₀₇土壤中的水溶性硫（H₂O—S）含量分别降低46.7%和44.7%，吸附性硫（Adsorbed—S）和盐酸可溶性硫（HCl—Soluble—S）含量分别增加0.4%，116.0%和50.1%，29.1%，而盐酸挥发性硫（HCl—Volatile—S）含量在R₂₀₀₂下降8.0%，在R₂₀₀₇增加19.7%。不同恢复阶段湿地土壤中各形态无机硫含量在生长季呈不同的变化特征，这一方面与不同湿地植物生长节律以及地上与地下之间的硫养分供给关系密切相关；另一方面则与不同生态补水方式导致的环境因子，尤其是pH、EC和氮养分的变化有关。随着恢复年限的增加，湿地土壤的总无机硫（TIS）含量以及其占全硫（TS）含量的比例均呈降低趋势。湿地土壤的TIS储量整体随恢复年限的增加而降低，而这种降低主要取决于H₂O—S、Adsorbed—S和HCl—Soluble—S的贡献，且以H₂O—S占优（78%~80%）。研究发现，随着黄河口湿地的逐渐恢复以及每年冬季芦苇收割活动的进行，恢复湿地土壤中的无机硫养分逐渐趋于缺乏状态，长期来看将不利于维持湿地的稳定与健康。     

黄土高原植被恢复过程中土壤表面电化学性质演变特征

土壤胶体表面所带电荷是土壤具有一系列物理、化学性质的根本原因。表面电荷数量、比表面积、表面电荷密度、表面电场强度以及表面电位是土壤胶体颗粒重要性质,影响土壤中物理、化学、生物化学过程。运用带电颗粒表面性质联合分析法,测定黄土高原子午岭地区不同植被类型下土壤表面电荷性质,研究自然植被恢复过程对土壤表面电荷性质的影响。结果表明:随着植被的演替,子午岭林区土壤表面电荷数量、比表面积、表面电荷密度均随植被的恢复增加,变化范围分别为10.88～19.85 cmol·kg~(–1)、40.67～61.71 m~2·g~(–1)和0.22～0.31 c·m~(–2),平均值分别为16.18 cmol·kg~(–1)、54.88 m2·g~(–1)和0.28 c·m~(–2),土壤表面电场强度达108 V·m~(–1)数量级;土壤黏粒、有机碳含量是影响表面电荷性质的主要因素,解释率分别为62.5%和27.9%;土壤基本性质对表面电荷性质的影响由强到弱依次为:黏粒、有机碳、砂粒、全氮、C/N、粉粒、碳酸钙、pH。研究结果对于进一步认识黄土高原土壤颗粒表面性质,加深理解土壤中发生的一系列物理化学过程具有重要意义。     

不同保水处理下苏丹草光合特性研究

为了研究矿区生态修复过程中植物对不同保水措施的生理响应,以常用修复植物苏丹草为研究对象,利用CIRAS-2型(PP-Systems)光合仪测定苏丹草的光合指标,探讨高温下苏丹草对不同保水措施的生理响应,以期为矿区生态修复中的保水措施提供理论依据。结果表明：不同保水处理下苏丹草的光合速率Pn和瞬间水分利用效率WUE日变化均呈“W”型曲线,蒸腾速率Tr日变化呈“M”型曲线。苏丹草的Pn有“午休”现象存在,主要受非气孔因素的影响。影响苏丹草Pn、Tr的主要环境因子为大气CO₂浓度Ca、大气温度Tc、大气相对湿度RH。在土壤上覆盖火烧石和添加粉煤灰均显著增大了苏丹草的Pn和WUE,增强了苏丹草适应高温环境的能力。从Pn的指标来看,土壤表面覆盖火烧石处理比土壤中添加粉煤灰处理的效果好,但两者同时作用效果略低于单独用火烧石处理,原因有待进一步研究。