Reviewing research priorities in weed ecology,evolution and management: a horizon scan

Weedy plants pose a major threat to food security, biodiversity, ecosystem services and consequently to human health and wellbeing. However, many currently used weed management approaches are increasingly unsustainable. To address this knowledge and practice gap, in June 2014, 35 weed and invasion ecologists, weed scientists, evolutionary biologists and social scientists convened a workshop to explore current and future perspectives and approaches in weed ecology and management. A horizon scanning exercise ranked a list of 124 pre‐submitted questions to identify a priority list of 30 questions. These questions are discussed under seven themed headings that represent areas for renewed and emerging focus for the disciplines of weed research and practice. The themed areas considered the need for transdisciplinarity, increased adoption of integrated weed management and agroecological approaches, better understanding of weed evolution, climate change, weed invasiveness and finally, disciplinary challenges for weed science. Almost all the challenges identified rested on the need for continued efforts to diversify and integrate agroecological, socio‐economic and technological approaches in weed management. These challenges are not newly conceived, though their continued prominence as research priorities highlights an ongoing intransigence that must be addressed through a more system‐oriented and transdisciplinary research agenda that seeks an embedded integration of public and private research approaches. This horizon scanning exercise thus set out the building blocks needed for future weed management research and practice; however, the challenge ahead is to identify effective ways in which sufficient research and implementation efforts can be directed towards these needs.     

Scenario simulation of water retention services under land use/cover and climate changes: a case study of the Loess Plateau,China

Comprehensive assessments of ecosystem services in environments under the influences of human activities and climate change are critical for sustainable regional ecosystem management. Therefore, integrated interdisciplinary modelling has become a major focus of ecosystem service assessment. In this study, we established a model that integrates land use/cover change (LUCC), climate change, and water retention services to evaluate the spatial and temporal variations of water retention services in the Loess Plateau of China in the historical period (2000-2015) and in the future (2020-2050). An improved Markov-Cellular Automata (Markov-CA) model was used to simulate land use/land cover patterns, and ArcGIS 10.2 software was used to simulate and assess water retention services from 2000 to 2050 under six combined scenarios, including three land use/land cover scenarios (historical scenario (HS), ecological protection scenario (EPS), and urban expansion scenario (UES)) and two climate change scenarios (RCP4.5 and RCP8.5, where RCP is the representative concentration pathway). LUCCs in the historical period (2000-2015) and in the future (2020-2050) are dominated by transformations among agricultural land, urban land and grassland. Urban land under UES increased significantly by 0.63×10³ km²/a, which was higher than the increase of urban land under HS and EPS. In the Loess Plateau, water yield decreased by 17.20×10⁶ mm and water retention increased by 0.09×10⁶ mm in the historical period (2000-2015), especially in the Interior drainage zone and its surrounding areas. In the future (2020-2050), the pixel means of water yield is higher under RCP4.5 scenario (96.63 mm) than under RCP8.5 scenario (95.46 mm), and the pixel means of water retention is higher under RCP4.5 scenario (1.95 mm) than under RCP8.5 scenario (1.38 mm). RCP4.5-EPS shows the highest total water retention capacity on the plateau scale among the six combined scenarios, with the value of 1.27×10⁶ mm. Ecological restoration projects in the Loess Plateau have enhanced soil and water retention. However, more attention needs to be paid not only to the simultaneous increase in water retention services and evapotranspiration but also to the type and layout of restored vegetation. Furthermore, urbanization needs to be controlled to prevent uncontrollable LUCCs and climate change. Our findings provide reference data for the regional water and land resources management and the sustainable development of socio-ecological systems in the Loess Plateau under LUCC and climate change scenarios.     

Model based decision support system for land use changes and socio-economic assessments

Hydrological models are often linked with other models in cognate sciences to understand the interactions among climate, earth, water, ecosystem, and human society. This paper presents the development and implementation of a decision support system(DSS) that links the outputs of hydrological models with real-time decision making on social-economic assessments and land use management. Discharge and glacier geometry changes were simulated with hydrological model, water availability in semiarid environments. Irrigation and ecological water were simulated by a new commercial software MIKE HYDRO. Groundwater was simulated by MODFLOW. All the outputs of theses hydrological models were taken as inputs into the DSS in three types of links: regression equations, stationary data inputs, or dynamic data inputs as the models running parallel in the simulation periods. The DSS integrates the hydrological data, geographic data, social and economic statistical data, and establishes the relationships with equations, conditional statements and fuzzy logics. The programming is realized in C++. The DSS has four remarkable features:(1) editable land use maps to assist decision-making;(2) conjunctive use of surface and groundwater resources;(3) interactions among water, earth, ecosystem, and humans; and(4) links with hydrological models. The overall goal of the DSS is to combine the outputs of scientific models, knowledge of experts, and perspectives of stakeholders, into a computer-based system, which allows sustainability impact assessment within regional planning; and to understand ecosystem services and integrate them into land and water management.     

Ecosystem service values of gardens in the Yellow River Basin,China

Studies on the ecosystem service value(ESV)of gardens are critical for informing evidence-based land management practices based on an understanding of the local ecosystem.By analyzing equivalent value factors(EVFs),this paper evaluated the values of 11 ecosystem services of gardens in the Yellow River Basin of China in 2019.High-precision land use survey data were used to improve the accuracy of the land use classification,garden areas,and spatial distribution of the ESVs of gardens.The results showed that garden ecosystem generally had high ESVs,especially in terms of the ESV of food production,which is worthy of further research and application to the practice of land use planning and management.Specifically,the value of one standard EVF of ecosystem services in 2019 was 3587.04 CNY/(hm²·a),and the ESV of food production of gardens was much higher than that of croplands.Garden ecosystem provided an ESV of 1348.66×10⁸CNY/a in the Yellow River Basin.The areas with the most concentrated ESVs of gardens were located in four regions:downstream in the Shandong-Henan zone along the Yellow River,mid-stream in the Shanxi-Shaanxi zone along the Yellow River,the Weihe River Basin,and upstream in the Qinghai-Gansu-Ningxia-Inner Mongolia zone along the Yellow River.The spatial correlation of the ESVs in the basin was significant(global spatial autocorrelation index Moran's I=0.464),which implied that the characteristics of high ESVs adjacent to high ESVs and low ESVs adjacent to low ESVs are prominent.In the Yellow River Basin,the contribution of the ESVs of gardens to the local environment and economy varied across regions.We also put forward some suggestions for promoting the construction of ecological civilization in the Yellow River Basin.The findings of this study provide important contributions to the research of ecosystem service evaluation in the Yellow River Basin.     

2005-2015年石羊河流域生态系统服务时空分异

生态系统服务研究是目前生态学领域的热点和前沿。以石羊河流域为研究区,借助GIS技术和方法,对流域2005、2010年和2015年的水源涵养、土壤保持、水质净化、碳储存、生物多样性、食品供给6项服务进行定量评估,并对不同地类的服务变化规律及生态系统功能分区进行探索与研究。结果表明：① 各服务类型在空间上表现出差异性规律：水源涵养、生物多样性、碳储存在空间上呈现西南高东北低,高值沿河流及周围带状分布的空间格局;水质净化高值区分布较为零碎;武威、永昌和民勤盆地等地为食品供给服务的高值区。② 在不同土地利用类型中,草地和耕地是承担生态系统供给服务的关键角色。③ 研究区划分为3项生态功能区,即祁连山生态保育区、流域绿洲生态功能区、荒漠生态功能区。通过对石羊河流域生态系统服务时空分异特征进行深入分析,以期为相关研究提供数据和方法支持,并为相关流域生态保护与建设目标提供科学参考。     

Application of the InVEST model for assessing water yield and its response to precipitation and land use in the Weihe River Basin,China

With realizing the importance of ecosystem services to society, the efforts to evaluate the ecosystem services have increased. As the largest tributary of the Yellow River, the Weihe River has been endowed with many ecological service functions. Among which, water yield can be a measure of local availability of water and an index for evaluating the conservation function of the region. This study aimed to explore the temporal and spatial variation of water yield and its influencing factors in the Weihe River Basin (WRB), and provide basis for formulating reasonable water resources utilization schemes. Based on the InVEST (integrated valuation of ecosystem services and tradeoffs) model, this study simulated the water yield in the WRB from 1985 to 2019, and discussed the impacts of climatic factors and land use change on water yield by spatial autocorrelation analysis and scenario analysis methods. The results showed that there was a slight increasing trend in water yield in the WRB over the study period with the increasing rate of 4.84 mm/10a and an average depth of 83.14 mm. The main water-producing areas were concentrated along the mainstream of the Weihe River and in the southern basin. Changes in water yield were comprehensively affected by climate and underlying surface factors. Precipitation was the main factor affecting water yield, which was consistent with water yield in time. And there existed significant spatial agglomeration between water yield and precipitation. Land use had little impact on the amount of water yield, but had an impact on its spatial distribution. Water yield was higher in areas with wide distribution of construction land and grassland. Water yield of different land use types were different. Unused land showed the largest water yield capacity, whereas grassland and farmland contributed most to the total water yield. The increasing water yield in the basin indicates an enhanced water supply service function of the ecosystem. These results are of great significance to the water resources management of the WRB.     

五台山地区森林生态系统服务功能价值评估

森林对维持我国自然生态系统的平衡和稳定具有重要意义,其服务功能价值越来越受到人们的重视。采用综合评价方法对五台山地区森林生态系统服务功能价值进行估算。结果表明:五台山地区森林生态系统服务功能总价值为101.47×108元,单位面积价值量为6.80元·m-2·a-1,其中供给功能价值为0.44×108元(占0.43%),支持功能价值为31.34×108元(占30.89%),调节功能价值为65.83×108元(占64.88%),文化服务功能价值为3.86×108元(占3.80%);从不同的服务功能类型来看,其价值量为:防风固沙维持营养物质循环涵养水源气候调节保护生物多样性休憩娱乐净化空气提供林产品控制侵蚀;不同森林类型价值量差异较大,灌丛最大,针阔混交林最小,从单位面积价值量来看,松杉类最大,灌丛最小;五台山地区森林生态系统服务功能价值巨大,该结果对区域生态系统管理具有重要意义。     

青海省土地利用变化对生态系统服务价值的影响研究

以1999年、2006年、2013年3年期青海省土地利用变更调查数据为基础,采用生态系统服务价值定量评估模型、土地利用动态度及敏感性指数对青海省土地利用变化情况及其对生态系统服务价值的影响情况进行分析。结果表明:(1)1999—2013年间,青海省林地、牧草地、园地及建设用地呈增长趋势;耕地、水域及未利用土地呈减少趋势。(2)区域生态系统服务总价值总体呈现出增长趋势,由1999年的4 477.29×108元提高至2013年的4 507.07×108元。研究期间,牧草地、林地、水域面积变化对区域生态系统服务价值起着决定性的作用,3类土地利用类型生态服务价值占总价值的96%以上。(3)各项生态系统服务功能中,水源涵养、土壤形成与保护及废物处理功能贡献率最大,表明青海省生态系统的服务性功能远高于生产性功能。(4)研究区生态系统服务价值对生态服务价值系数缺乏弹性,研究结果具有可信性。     

Modeling and analyzing supply-demand relationships of water resources in Xinjiang from a perspective of ecosystem services

Water shortage is one bottleneck that limits economic and social developments in arid and semi-arid areas.As the impacts of climate change and human disturbance intensify across time,uncertainties in both water resource supplies and demands increase in arid and semi-arid areas.Taking a typical arid region in China,Xinjiang Uygur Autonomous Region,as an example,water yield depth(WYD)and water utilization depth(WUD)from 2002 to 2018 were simulated using the Integrated Valuation of Ecosystem Services and Tradeoffs(InVEST)model and socioeconomic data.The supply-demand relationships of water resources were analyzed using the ecosystem service indices including water supply-demand difference(WSDD)and water supply rate(WSR).The internal factors in changes of WYD and WUD were explored using the controlled variable method.The results show that the supplydemand relationships of water resources in Xinjiang were in a slight deficit,but the deficit was alleviated due to increased precipitation and decreased WUD of irrigation.WYD generally experienced an increasing trend,and significant increase mainly occurred in the oasis areas surrounding both the Junggar Basin and Tarim Basin.WUD had a downward trend with a decline of 20.70%,especially in oasis areas.Water resources in most areas of Xinjiang were fully utilized and the utilization efficiency of water resources increased.The water yield module in the InVEST model was calibrated and validated using gauging station data in Xinjiang,and the result shows that the use of satellite-based water storage data helped to decrease the bias error of the InVEST model by 0.69×10⁸m³.This study analyzed water resource supplies and demands from a perspective of ecosystem services,which expanded the scope of the application of ecosystem services and increased the research perspective of water resource evaluation.The results could provide guidance for water resource management such as spatial allocation and structural optimization of water resources in arid and semi-arid areas.     

塔里木河下游典型区景观生态质量评价

近20年来,由于人类对水资源利用的不合理,塔里木河下游生态环境持续恶化,大西海子水库以下河段自1974年以来至2000年全部断流。本文选取卡拉～台特马湖段呈东南向分布的狭长地带为典型区,以2000年的TM影像为数据源,在RS和GIS技术的支持下提取了土地利用程度及植被类型因子,结合地下水位对塔里木河下游典型区进行了景观生态质量综合评价。研究将典型区按景观生态质量高低分为好、一般、较差、差和极差五个等级,结果表明:质量优的景观多是河道附近呈斑块状分布的人工绿洲,质量差的景观是塔里木河下游典型区的主体,景观质量较差的景观面积占典型区的98.91％,主要分布在距离河道比较远的地区和英苏以下地段。以上研究结果可为生态治理规划提供科学依据。     

土地利用变化对塔里木河中游胡杨林的影响研究

本研究区位于塔里木河中游地区,本研究选取耕地变化、输水堤防的建设以及油气田开发三种土地利用方式,在大量野外调查的基础上,在3S技术和历史数据的支持下,分析了这些土地利用方式变化对胡杨林生态系统的影响。研究结果表明:研究区1992年之后内耕地大量增加,输水堤防对堤防内外侧胡杨生态系统具有不同影响,油气田开发会造成生态破坏和环境污染等问题。     

陕西关中地区土地生态价值时空动态

为探明土地生态系统服务价值的空间差异性,以关中地区遥感影像、气象气候、土壤植被及地形地貌数据为依据,借助格网插值技术和土壤潜力测算模型获取土壤潜力栅格图,运用土地利用栅格图及生态系统服务价值当量因子加权,生成土地生态系统服务价值栅格图;从而在栅格尺度上揭示土地生态系统服务价值的空间异质性。结果表明:1986—2007年间,关中地区土地生态系统服务价值总量由509.61亿元增加到561.02亿元,增幅约为10.09%,2000—2007年段增速约为1986—2000年段的33.65倍;周边山地和黄土梁峁区生态价值增加,增量最大的为周至县;中部平原区的生态价值量减少,减量最大的是西安市区;研究期内的土地利用结构调整取得了较明显的生态效益。     

宁夏固原市生态保育对农民福祉的影响初探

基于土地利用图、统计年鉴及农户调研数据,分析宁夏固原市1995年和2005年食物供给、能源供给、水源涵养、就业供给与收入供给5大生态系统服务的空间格局及变化;通过分析人类对生态系统服务消费需求的满足程度,定量了研究区农民福祉及变化;结合土地利用变化数据,探讨生态保育对农民福祉的影响。结果表明：从1995-2005年,固原市各县农民福祉有大幅提高,其中大多由于收入福祉与食物福祉的增加。整个固原市农民福祉的提高70.4%是来源于耕地生产力的增强,24.0%是由于生态保育。在生态保育对农民福祉的增加中,有26.9%是由于退耕还林还草对农民的补贴,70.5%是由于增强了当地的水源涵养功能。     

塔里木河流域环境信息系统开发研究

环境信息系统是塔里木河流域水量调度管理系统的一个专业分析子系统.通过计算生物丰度指数、植被覆盖指数、水网密度指数、土地退化指数和污染负荷指数进行环境质量评价;采用"植株潜水蒸发定额法"来计算维持天然植被现状的生态需水量;结合生态风险评价思想和景观生态学方法,分别计算生态退化指数、风险度指数和易恢复度指数,构建一个生态风险强度指数进行相应的生态风险分析评价,从而探讨系统建设总体方案、系统的功能和结构以及与其他子系统集成问题.实践表明,将理论研究成果,通过ArcGIS+Oracle9i+ArcSDE技术来开发环境信息系统具有较强的实用性和可操作性,能够为干旱区环境作出科学的评价,也可为其他相关系统开发提供一定的参考.     

塔里木河流域土地荒漠化现状分析

以塔里木河流域为对象,采用遥感与地理信息相结合的方法获取塔里木河流域土地荒漠化现状.结果表明,塔里木河流域土地荒漠化面积占调查区面积的73.60%.在荒漠化主导因素中,塔里木河流域以风蚀为主的荒漠化土地类型,占荒漠化土地面积的73.61%.在荒漠化程度中,以极重度为主,占荒漠化土地的35.41%;在荒漠化土地利用类型中,以未利用土地荒漠化为主,占荒漠化面积的48.45%;在空间分布上,以塔里木河流域中下游荒漠化土地所占比重最大.     

塔里木河干流绿洲250年人类活动、环境变化及可持续发展模式研究

塔里木河是中国最大的内陆河流,其绿洲可持续发展决定着新疆南疆地区的经济发展与环境稳定。文中根据历史文献和野外考察,分析18世纪中期-20世纪50年代的塔河人类活动与环境变化;利用遥感和GIS技术,获取塔里木河干流上、中、下游1973年、1990年、2000年和2008年土地利用/覆被数据;利用生态系统服务价值理论,分析1973-2008年土地利用/覆被变化的生态环境变化,并利用相关分析方法判断这种变化的驱动因子。结果显示:20世纪50年代以前,人工绿洲主要在源流进行,干流是天然绿洲环境,受制于河流特性的影响;以后人工绿洲开发主要在干流进行,以干流生态环境退化为代价,驱动其变化的是人口、经济利益、政策和资本等人文因素。在此基础上,利用自组织理论和利益相关者理论,建立了塔河干流绿洲可持续发展模式。     

塔里木河流域土地荒漠化的现状、成因及防治对策

本文分析了塔里木河流域土地荒漠化的现状和形成原因 ,阐述了自然因素及人为因素在土地荒漠化过程中的交互作用 ,人类不合理的经济活动是叠加在自然因素之上对土地荒漠化的发生和扩展起着“催化剂”的作用。提出了流域综合整治措施 ,加强塔河水资源利用管理、保护天然植被、营造防风林、发展节水农业、合理耕作、提高人民群众生态意识等防治土地荒漠化的有效措施     

Transdisciplinary weed research: new leverage on challenging weed problems?

Transdisciplinary weed research (TWR) is a promising path to more effective management of challenging weed problems. We define TWR as an integrated process of inquiry and action that addresses complex weed problems in the context of broader efforts to improve economic, environmental and social aspects of ecosystem sustainability. TWR seeks to integrate scholarly and practical knowledge across many stakeholder groups (e.g. scientists, private sector, farmers and extension officers) and levels (e.g. local, regional and landscape). Furthermore, TWR features democratic and iterative processes of decision‐making and collective action that aims to align the interests, viewpoints and agendas of a wide range of stakeholders. The fundamental rationale for TWR is that many challenging weed problems (e.g. herbicide resistance or extensive plant invasions in natural areas) are better addressed systemically, as a part of broad‐based efforts to advance ecosystem sustainability, rather than as isolated problems. Addressing challenging weed problems systemically can offer important new leverage on such problems, by creating new opportunities to manage their root causes and by improving complementarity between weed management and other activities. While promising, this approach is complicated by the multidimensional, multilevel, diversely defined and unpredictable nature of ecosystem sustainability. In practice, TWR can be undertaken as a cyclic process of (i) initial problem formulation, (ii) ‘broadening’ of the problem formulation and recruitment of stakeholder participants, (iii) deliberation, negotiation and design of an action agenda for systemic change, (iv) implementation action, (v) monitoring and assessment of outcomes and (vi) reformulation of the problem situation and renegotiation of further actions. Notably, ‘purposive’ disciplines (design, humanities and arts) have central, critical and recurrent roles in this process, as do integrative analyses of relevant multidimensional and multilevel factors, via multiple natural and social science disciplines. We exemplify this process in prospect and retrospect. Importantly TWR is not a replacement for current weed research; rather, the intent is to powerfully leverage current efforts.     

Land use/land cover change responses to ecological water conveyance in the lower reaches of Tarim River,China

The Tarim River is the longest inland river in China and is considered as an important river to protect the oasis economy and environment of the Tarim Basin. However, excessive exploitation and over-utilization of natural resources, particularly water resources, have triggered a series of ecological and environmental problems, such as the reduction in the volume of water in the main river, deterioration of water quality, drying up of downstream rivers, degradation of vegetation, and land desertification. In this study, the land use/land cover change (LUCC) responses to ecological water conveyance in the lower reaches of the Tarim River were investigated using ENVI (Environment for Visualizing Images) and GIS (Geographic Information System) data analysis software for the period of 1990-2018. Multi-temporal remote sensing images and ecological water conveyance data from 1990 to 2018 were used. The results indicate that LUCC covered an area of 2644.34 km² during this period, accounting for 15.79% of the total study area. From 1990 to 2018, wetland, farmland, forestland, and artificial surfaces increased by 533.42 km² (216.77%), 446.68 km² (123.66%), 284.55 km² (5.67%), and 57.51 km² (217.96%), respectively, whereas areas covered by grassland and other land use/land cover types, such as Gobi, bare soil, and deserts, decreased by 103.34 km² (14.31%) and 1218.83 km² (11.75%), respectively. Vegetation area decreased first and then increased, with the order of 2010<2000<1990<2018. LUCC in the overflow and stagnant areas in the lower reaches of the Tarim River was mainly characterized by fragmentation, irregularity, and complexity. By analyzing the LUCC responses to 19 rounds of ecological water conveyance in the lower reaches of the Tarim River from 2000 to the end of 2018, we proposed guidelines for the rational development and utilization of water and soil resources and formulation of strategies for the sustainable development of the lower reaches of the Tarim River. This study provides scientific guidance for optimal scheduling of water resources in the region.     

塔里木河下游沙漠化对绿洲农业生产的影响

荒漠化是全世界所面临的重大的环境灾害之一。塔里木河下游的沙漠化已经对该区域的绿洲农业生产产生了巨大的危害。本文通过对塔里木河下游沙漠化状况和典型生产团场农业生产状况的调查研究发现 ,沙漠化对塔里木河下游农业生产的影响 ,主要表现为下游来水量逐年减少 ,弃耕地面积增加 ;沼泽土面积减少 ,肥沃土壤面积增加 ;风灾、旱灾面积增加 ,盐碱灾害面积相对减少。减轻沙漠化对绿洲农业危害的措施 ,包括加强管理 ,增加塔里木河的来水量 ;发展节水灌溉技术 ,减少水资源浪费 ;调整作物结构 ,提高水资源利用率 ;保护荒漠植被 ,维护生态 ,完善防护林体系。