The impact of interventions in the global land and agri‐food sectors on Nature’s Contributions to People and the UN Sustainable Development Goals

Interlocked challenges of climate change, biodiversity loss, and land degradation require transformative interventions in the land management and food production sectors to reduce carbon emissions, strengthen adaptive capacity, and increase food security. However, deciding which interventions to pursue and understanding their relative co‐benefits with and trade‐offs against different social and environmental goals have been difficult without comparisons across a range of possible actions. This study examined 40 different options, implemented through land management, value chains, or risk management, for their relative impacts across 18 Nature's Contributions to People (NCPs) and the 17 Sustainable Development Goals (SDGs). We find that a relatively small number of interventions show positive synergies with both SDGs and NCPs with no significant adverse trade‐offs; these include improved cropland management, improved grazing land management, improved livestock management, agroforestry, integrated water management, increased soil organic carbon content, reduced soil erosion, salinization, and compaction, fire management, reduced landslides and hazards, reduced pollution, reduced post‐harvest losses, improved energy use in food systems, and disaster risk management. Several interventions show potentially significant negative impacts on both SDGs and NCPs; these include bioenergy and bioenergy with carbon capture and storage, afforestation, and some risk sharing measures, like commercial crop insurance. Our results demonstrate that a better understanding of co‐benefits and trade‐offs of different policy approaches can help decision‐makers choose the more effective, or at the very minimum, more benign interventions for implementation.     

Long‐term research avoids spurious and misleading trends in sustainability attributes of no‐till

Agricultural management recommendations based on short‐term studies can produce findings inconsistent with long‐term reality. Here, we test the long‐term environmental sustainability and profitability of continuous no‐till agriculture on yield, soil water availability, and N₂O fluxes. Using a moving window approach, we investigate the development and stability of several attributes of continuous no‐till as compared to conventional till agriculture over a 29‐year period at a site in the upper Midwest, US. Over a decade is needed to detect the consistent effects of no‐till. Both crop yield and soil water availability required 15 years or longer to generate patterns consistent with 29‐year trends. Only marginal trends for N₂O fluxes appeared in this period. Relative profitability analysis suggests that after initial implementation, 86% of periods between 10 and 29 years recuperated the initial expense of no‐till implementation, with the probability of higher relative profit increasing with longevity. Importantly, statistically significant but misleading short‐term trends appeared in more than 20% of the periods examined. Results underscore the importance of decadal and longer studies for revealing consistent dynamics and emergent outcomes of no‐till agriculture, shown to be beneficial in the long term.     

Sustainable intensification of crop residue exploitation for bioenergy: Opportunities and challenges

Crop residue exploitation for bioenergy can play an important role in climate change mitigation without jeopardizing food security, but it may be constrained by impacts on soil organic carbon (SOC) stocks, and market, logistic and conversion challenges. We explore opportunities to increase bioenergy potentials from residues while reducing environmental impacts, in line with sustainable intensification. Using the case study of North Rhine‐Westphalia in Germany, we employ a spatiotemporally explicit approach combined with stakeholder interviews. First, the interviews identify agronomic and environmental impacts due to the potential reduction in SOC as the most critical challenge associated with enhanced crop residue exploitation. Market and technological challenges and competition with other residue uses are also identified as significant barriers. Second, with the use of agroecosystem modelling and estimations of bioenergy potentials and greenhouse gas emissions till mid‐century, we evaluate the ability of agricultural management to tackle the identified agronomic and environmental challenges. Integrated site‐specific management based on (a) humus balancing, (b) optimized fertilization and (c) winter soil cover performs better than our reference scenario with respect to all investigated variables. At the regional level, we estimate (a) a 5% increase in technical residue potentials and displaced emissions from substituting fossil fuels by bioethanol, (b) an 8% decrease in SOC losses and associated emissions, (c) an 18% decrease in nitrous oxide emissions, (d) a 37% decrease in mineral fertilizer requirements and emissions from their production and (e) a 16% decrease in nitrate leaching. Results are spatially variable and, despite improvements induced by management, limited amounts of crop residues are exploitable for bioenergy in areas prone to SOC decline. In order to sustainably intensify crop residue exploitation for bioenergy and reconcile climate change mitigation with other sustainability objectives, such as those on soil and water quality, residue management needs to be designed in an integrated and site‐specific manner.     

水分驱动下茵陈蒿(Artemisia capillaris Thunb.)地上生物量模型与异速生长特征

构建生物量预估模型,探究生物量在各器官中的分配策略和异速生长关系及其对环境因子的响应,对理解植物群落结构、功能、碳储存和分配机制具有重要意义。本研究以内蒙古荒漠草原常见种茵陈蒿(Artemisia capillaris Thunb.)为对象,在不同水分处理下,利用易测指标,如株高、基径、分枝数、冠幅和生物量等参数建立生物量模型,采用标准化主轴分析法分析其异速生长关系。结果表明:在不同水分处理下,茵陈蒿的最佳生物量预估模型的变量选择不同;不同水分处理下茵陈蒿各器官间、各器官与地上生物量间的异速生长关系不同,但相对于自然降水量,增水和减水50%下均为等速生长,这说明在不同水分条件下茵陈蒿对各器官间的资源配置存在权衡策略,符合最优分配假说;而在极端气候条件下,各器官对资源的竞争会变弱;在荒漠草原中,对草本植物进行生物量模拟,选择预测变量和方程模型时,应考虑生长季降水量。本研究可为荒漠草原草本植物生物量预估模型的建立和异速生长关系对环境因子适应的理解等提供方法支持及理论依据。     

“2020年后全球生物多样性框架”进展及展望

“2020年后全球生物多样性框架”是当前《生物多样性公约》谈判的焦点议题之一。本文阐述了框架制定的背景, 介绍了“2020年后全球生物多样性框架”不限成员名额工作组(Open Ended Working Group, OEWG),的谈判过程, 综合分析了缔约方在各有关磋商进程中的观点, 以及目前缔约方对框架各个要素的共识和分歧, 评估了框架的制定进展, 并就框架的设计提出四点展望: (1)阐明转型变革的具体实施路径; (2)平衡反映公约三大目标; (3)加强与其他全球治理进程的协同; (4)强化框架对全球及缔约方履约进展的评估和审查。最后提出对我国的建议: (1)及时更新国家生物多样性战略与行动计划(National Biodiversity Strategies and Action Plans, NBSAP); (2)加强国内生物多样性工作的协调; (3)继续加强生态环境执法和责任机制。为缔约方更好参与框架制定进程, 深入了解框架及其磋商进展提供参考, 并为下一步框架制定提供参考。     

基于文献计量的微藻收获技术研究分析

微藻是能以自养模式固定二氧化碳,生成生物能源的原料,对可持续发展具有重要意义。微藻也能以异养模式生长,用于废水处理和积累高附加值物质。目前,微藻收获的成本占总成本的20%~30%。微藻收获技术已经成为研究热点。本文从文献计量的角度分析了各国微藻收获的研究进展以及我国的研究现状,并展望了微藻收获技术发展趋势,为进一步研究提供参考。     

生物炭对农田土壤氨挥发的影响机制研究进展

降低土壤氨挥发量是农田生态系统中减少土壤氮素损失、提高氮肥利用率的关键途径之一。生物炭具有独特的理化性质,施入土壤后可改变土壤理化性状,影响土壤氮素循环,并对农田土壤中氨挥发产生重要的影响。本文首先介绍了稻田和旱田两种土地利用方式下农田氨挥发过程及其影响因素(气候条件、土壤环境、施肥管理等);其次,重点综述了生物炭对农田生态系统氨挥发影响的研究进展,并从物理吸附机制、气液平衡机制、生物化学过程调节机制等方面探讨了生物炭介入下农田土壤氨挥发的响应机制,认为土壤氨挥发减排的响应主要是基于生物炭表面含氧官能团对土壤NH₄⁺和NH₃的吸附作用及促进土壤硝化作用;而生物炭增加土壤氨挥发排放主要与生物炭提高土壤pH值和透气性、增强土壤有机氮矿化微生物活性有关。最后,对生物炭减少土壤氨挥发、提高氮肥利用率的研究方向进行了展望。     

南北疆区域经济差异化三维生态足迹自然资本利用的时空演变

如何刻画自然资源消费在区域间的流转机制及其对生态的影响,是测度区域可持续发展的难点。采用改进后的三维生态足迹模型并引入存量流量利用比和资本流量占用率,对2003—2018年新疆区域三维生态足迹进行核算,并分别测度新疆各地州市自然资本利用的程度,聚焦南北疆地区自然资本利用的差异性,利用偏最小二乘法(PLS)找出影响生态足迹变化的动因,最后结合基尼系数及差异系数量化南北疆经济差异程度,从自然和经济视角探究南北疆可持续发展态势与差异。结果表明:①2003—2018年新疆人均生态足迹持续增长,增长幅度为119.94%,人均生态承载力基本保持在1.7 hm~2左右,流量资本占用强度不断增加,生态赤字问题愈发严重。②研究期内,南北疆地区生态足迹的增长幅度和速度存在明显空间差异,呈现"北高快,南低慢"的态势。各地州市生态赤字情况呈现不同程度的增长趋势,高值区为北疆的克拉玛依市及天山北坡经济带。③第一产业增加值对生态足迹正向驱动作用最为显著,第三产业增加值对生态足迹起到逆向驱动作用。④2003—2018年间,南北疆地区基尼系数维持在0.4—0.5之间,处于中警警度水平,南北疆区域经济差异系数变化波动不大,北疆区域经济差异系数明显高于南疆区域。     

景感生态学在城市生态系统服务中的应用研究——以城市公园景观设计为例

城市生态系统服务和可持续发展是当前城市生态学研究的热点问题。景感生态学作为联系生态系统服务和可持续发展的桥梁,可作为研究城市生态系服务和可持续发展的一种有效途径。随着社会发展所伴随的人们经济生活的生活压力增大,城市居民的亚健康状态日益突出。城市公园作为城市生态系统的重要构成,其设计目的应考虑应对城市居民健康问题和促进人类精神文明建设方面的作用。以城市公园景观设计为例,从园路、建筑、植物、水体景观和小品等方面探讨景感生态学在城市公园景观设计中的应用价值。景感生态学作为探索城市公园景观设计的新思路,以实现生态效益和居民福祉的提升,丰富和提升城市公园的生态系统服务功能,从而有利于促进为人类当代和后代提供可持续的福祉,以期驱使人类行为和言行规律朝着对生态系统有益的方向演化,自觉维护和改善生态系统服务,从而可持续地保障城市生态系统服务。     

应对气候和生态环境危机促进全球可持续发展——UNEP与自然和谐共处报告简述

2021年2月18日,联合国环境署发布《与自然和谐共处：应对气候、生物多样性和污染危机的科学蓝图》。报告指出：气候变化、生物多样性下降和环境污染已经成为全球三大环境紧急情况;人与自然关系面临着社会经济发展压力加剧环境风险、遏制环境恶化的全球承诺尚未兑现、环境风险威胁可持续发展目标等多重挑战;全球亟需开展以联合国可持续发展目标为框架的系统变革,加快应对全球环境危机的重点行动,改革资源环境和经济系统,提高粮食、能源和水系统的环境友好性与可持续性,加强对人体健康与生态环境健康的协同保护,进而推动人与自然的和谐共处以及可持续发展。该报告结合全球环境评估的最新进展,强调了社会-经济-环境可持续发展仍是未来的重要研究课题,对我国社会-生态系统与可持续发展等领域的科学研究有如下启示：（1）创新社会-生态系统的综合集成研究,探寻不同发展路径和气候变化情景下社会-生态系统时空演变特征与趋势;（2）注重科学研究对决策的支撑以及与国际重大议程的衔接,探索和创新可持续发展的中国方案。