气候变化和人类活动对流域水文恢复力影响的研究进展

水文恢复力是流域或生态系统维持水文稳定性的重要参考指标,深入研究植被结构和水文恢复力之间的关系是未来在全球变化背景下生态水文学的重要方向。但目前水文恢复力对气候变化与人类活动等不同干扰方式的响应机制还缺乏系统的研究,水文恢复力的形成机制及其与植被结构的关系也尚无全面的认识。系统总结了当前水文恢复力的主要概念,从水分利用效率、Budyko框架的水平衡、植被景观结构变化与受到干旱干扰的恢复时间等不同角度总结了5种主要的算法,分析了气候变化、人类活动和植被结构对水文恢复力的响应特点并分析了水文恢复力发挥作用的内在机制。结果表明：(1)Budyko模式和生态系统水分利用效率在水文恢复力的计算中具有重要价值;(2)在能量限制的流域,水文恢复力随着暖干化程度增大而减小;在水分限制的流域,水文恢复力随着暖干化程度增大而增大;(3)森林主导的流域比其他生物群落主导的流域具有更高的水文恢复力;(4)大面积森林采伐或者造林通常会降低流域的水文恢复力;(5)天然林、多样性较高的植被结构有利于维持较高的水文恢复力;(6)干扰条件下植被水分利用效率较高的流域有利于维持较高的水文恢复力;(7)流域植被类型的多样性...     

鄂尔多斯社会—生态系统恢复力评价及驱动机制研究

在对社会—生态系统恢复力概念界定的基础上,运用熵值法和集对分析相结合的研究方法,从脆弱性、应对能力两大层面出发,构建复合系统恢复力测度模型,以典型矿业城市鄂尔多斯为例,分析恢复力的演变趋势及驱动机制。结果表明:(1)应对能力对恢复力的影响居于主导地位,2001—2013年鄂尔多斯社会—生态系统恢复力指数呈现缓慢上升趋势。(2)作用因子对于恢复力的驱动主要以二次线性关系为主,具有较大的不确定性。建议发展除矿产资源开采以外的支撑性产业,减少资源开发对环境带来的负面影响,鼓励节约集约利用资源,有效提高系统的应急能力,增强复合系统的恢复力。     

基于韧性评价方法的乡镇旅游评估——以汶川县卧龙镇为例

【目的】 基于乡村振兴以及乡镇旅游业加速发展的背景下,对大熊猫国家公园内卧龙镇主要的旅游资源和经济社会状况进行分析,评价汶川县卧龙镇整体的旅游韧性。【方法】 文章通过对卧龙镇的基础资料分析研究和实地踏勘,从安全防控、生态环境、旅游模式、服务人群四个方面综合评价研究区旅游韧性。【结果】 卧龙镇整体旅游韧性亟需提升,安全防控韧性较差,减灾防灾的应急能力和医疗服务保障力较弱;生物多样性较好,但随着经济发展生态韧性不断减弱,一定程度上限制了旅游的发展;卧龙镇服务人群韧性较其他几项韧性稍强,但在增加就业岗位,扩大市场客源方面也需加强。【结论】 针对4个不同的方面提出提升乡镇旅游韧性的建议,提出构建防减灾技术支撑体系、绿色交通体系、基础设施体系、服务保障体系四大支撑体系;生态方面集约用地,避免旅游过度开发,建立多元治理体系;经济韧性发展上多元产业,强化农旅融合,提升产业链韧性。改善原有的乡镇旅游模式,使得乡镇的本土风貌、人文特色依托于乡镇旅游得以传承。     

土壤生态系统服务功能表征与计量

2015年是世界土壤年,健康的土壤是地球可持续发展的基石。然而,由于人类直接或间接的干扰,如土地利用变化、土壤管理和土地退化,使得土壤在全球变化压力下变得愈加脆弱。土壤在生态系统服务供应中发挥着至关重要的作用,土壤所提供的各种生态系统服务之间的相互协同或抵消作用是土壤生态系统服务功能研究的主要内容。土壤的碳、氮、水三大生物地球化学循环以及土壤的生物多样性与供给、调节、支持和文化四个生态系统服务紧密相关。为探索土壤可持续管理途径,提升土壤的生态系统服务能力,从碳、氮、水循环与生物多样性出发进行土壤生态系统服务功能表征与计量方法学研究亟待进行。开发用于评价土地利用和土壤管理可持续性的生态系统服务指标体系,采用多尺度、多目标、多因素集成分析探讨各生态系统服务之间的协同或抵消效应是研究的难点,而模型模拟可以在土壤生态系统服务功能计量研究中扮演重要的角色。     

数字普惠金融与农业产业链韧性耦合协调及影响因素

为探究数字普惠金融与农业产业链韧性耦合协调及其影响因素,基于2012—2021年中国31个省域面板数据（统计数据未含港澳台地区,下同）,在构建农业产业链韧性指标体系的基础上,借助熵权法评估数字普惠金融与农业产业链韧性水平,并通过耦合协调度模型、核密度估计分析两者耦合协调的时空演化特征,在此基础上,采用空间计量模型探究影响两者耦合协调发展的因素。研究发现：1）时间维度上,数字普惠金融与农业产业链韧性耦合协调关系趋于增强,整体呈缓慢上升趋势。其中,农业产业链韧性提升趋缓,数字普惠金融快速发展已成为推动两者耦合协调发展的重要因素。2）空间维度上,数字普惠金融与农业产业链韧性耦合协调度呈现“点状分散—块状集聚”的空间演化特征,极度失调、低度协调区逐渐消失,逐渐形成西北、西南方向“陷落”的空间格局。3）经济发展水平、财政支农水平、城镇化水平对两者耦合协调发展具有正向促进作用,城乡收入差距具有负向抑制作用。鉴于此,应强化区域协同发展理念,充分挖掘协同发展潜力,因地制宜实现数字普惠金融与农业产业链韧性协调高质量发展。     

茶农生计恢复力测度及影响因素研究——以安溪县为例

依据生计恢复力理论,结合可持续生计分析框架,构建茶农生计恢复力测度指标体系,选取福建省安溪县作为研究区域,运用综合指数法和多元线性回归模型,测度茶农生计恢复力并识别其影响因素.研究结果显示:(1)茶农生计恢复力指数由高到低依次为:务工主导型>务农主导型>纯农业型,总体呈现由非农收入主导向纯农业收入逐渐减弱的态势,并且不...     

Identifying spawner biomass per‐recruit reference points from life‐history parameters

Analysis of spawning biomass per‐recruit has been widely adopted in fisheries management. Fishing mortality expressed as spawning potential ratio (SPR) often requires a reference point as an appropriate proxy for the fishing mortality that supports a maximum sustainable yield—F_MSY. To date, a single generic level between F_30% and F_40% is routinely used. Using records from stock assessments in the RAM Legacy Database (RAMLD), we confirm that SPR at MSY (SPR_MSY) is a declining function of stock productivity quantified by F_MSY. We then use general linear models (GLM) and Bayesian errors‐in‐variables models (BEIVM) to show that SPR_MSY can be predicted from life‐history parameters (LHPs, including maximum lifespan, age‐ and length‐at‐maturation, growth parameters, natural mortality, and taxonomic Class) as well as gear selectivity. The calculated SPR_MSY ranges from about 13% to 95% with a mean of 47%. About 64% of the stocks in the RAMLD require SPR_MSY > 40%. Modelling SPR_MSY reveals that LHPs plus Class explain 61% of the deviance in SPR_MSY. Faster‐growing, low‐survival, and short‐lived species generally require a high SPR. With equal LHPs, elasmobranchs require about 20% higher SPR_MSY than teleosts. When F_MSY is estimated from fisheries that harvest older fish, increasing the vulnerable age by one year leads to about an 8% increase in SPR_MSY. The BEIVM yields smaller variance and bias than the GLM. The models developed in this study could be used to predict SPR_MSY reference points for new stocks using the same LHPs for calculating F_x%, but without knowledge of the stock‐recruitment parameters.     

Early Warnings for State Transitions

New concepts have emerged in theoretical ecology with the intent to quantify complexities in ecological change that are unaccounted for in state-and-transition models and to provide applied ecologists with statistical early warning metrics able to predict and prevent state transitions. With its rich history of furthering ecological theory and its robust and broad-scale monitoring frameworks, the rangeland discipline is poised to empirically assess these newly proposed ideas while also serving as early adopters of novel statistical metrics that provide advanced warning of a pending shift to an alternative ecological regime. We review multivariate early warning and regime shift detection metrics, identify situations where various metrics will be most useful for rangeland science, and then highlight known shortcomings. Our review of a suite of multivariate-based regime shift/early warning indicators provides a broad range of metrics applicable to a wide variety of data types or contexts, from situations where a great deal is known about the key system drivers and a regime shift is hypothesized a priori, to situations where the key drivers and the possibility of a regime shift are both unknown. These metrics can be used to answer ecological state-and-transition questions, inform policymakers, and provide quantitative decision-making tools for managers.     

Evolutionarily persistent and evolutionarily stable strategies in plant pathosystems

Summary Using gene-for-gene relationships as a basis for comparison, I show that Robinson's (1979, 1980) concept of an evolutionarily stable strategy, or ESS for short, is very different from the original definition of Maynard Smith & Price (1973) and, in fact, contradicts it in a number of important respects. The notion of an evolutionarily persistent strategy, or EPS for short, is introduced to clarify these differences and to reduce the potential for confusion in the future. The EPS concept is developed in terms of Holling's (1973) concept of resilience and Van Valen's (1976) notion of expansive energy. The combination of an ESS (sensu Maynard Smith & Price, 1973) and an EPS is offered as an alternative to Robinson's (1979, 1980) ESS concept. Robinson's recommendations for a holistic approach to plant pathosystem management are supported.