Evaluating regional resiliency of coastal wetlands to sea level rise through hypsometry‐based modeling

Sea level rise (SLR) threatens coastal wetlands worldwide, yet the fate of individual wetlands will vary based on local topography, wetland morphology, sediment dynamics, hydrologic processes, and plant‐mediated feedbacks. Local variability in these factors makes it difficult to predict SLR effects across wetlands or to develop a holistic regional perspective on SLR response for a diversity of wetland types. To improve regional predictions of SLR impacts to coastal wetlands, we developed a model that addresses the scale‐dependent factors controlling SLR response and accommodates different levels of data availability. The model quantifies SLR‐driven habitat conversion within wetlands across a region by predicting changes in individual wetland hypsometry. This standardized approach can be applied to all wetlands in a region regardless of data availability, making it ideal for modeling SLR response across a range of scales. Our model was applied to 105 wetlands in southern California that spanned a broad range of typology and data availability. Our findings suggest that if wetlands are confined to their current extents, the region will lose 12% of marsh habitats (vegetated marsh and unvegetated flats) with 0.6 m of SLR (projected for 2050) and 48% with 1.7 m of SLR (projected for 2100). Habitat conversion was more drastic in wetlands with larger proportions of marsh habitats relative to subtidal habitats and occurred more rapidly in small lagoons relative to larger sites. Our assessment can inform management of coastal wetland vulnerability, improve understanding of the SLR drivers relevant to individual wetlands, and highlight significant data gaps that impede SLR response modeling across spatial scales. This approach augments regional SLR assessments by considering spatial variability in SLR response drivers, addressing data gaps, and accommodating wetland diversity, which will provide greater insights into regional SLR response that are relevant to coastal management and restoration efforts.     

Eight decades of invasion by Chromolaena odorata (Asteraceae) and its biological control in West Africa: the story so far

ABSTRACT

Chromolaena odorata (L.) R.M. King and H. Robinson (Asteraceae) is a perennial weedy shrub of neotropical origin and a serious biotic threat in its invasive range. The Asian-West Africa (AWA) biotype of C. odorata present in West Africa is both morphologically and genetically different from the southern African (SA) biotype. The AWA biotype was first introduced into Nigeria in the late 1930s and rapidly spread across West Africa. Currently, 12 of the 16 countries in West Africa have been invaded, with significant negative effects on indigenous flora and fauna. However, locals in West Africa have found several uses for the weed. As chemical, physical and other conventional methods were unsustainable, costly and largely ineffective, three biological control agents, Apion brunneonigrum (Coleoptera: Brentidae), Pareuchaetes pseudoinsulata (Lepidoptera: Erebidae) and Cecidochares connexa (Diptera: Tephritidae), have been released in West Africa between the 1970s and the early 2000s. However, only C. connexa and P. pseudoinsulata established, contributing to the control of the weed, in six and four countries in West Africa respectively. Limited research funding, the absence of post-release evaluations of the established agents, and the ‘conflict of interest’ status of C. odorata (i.e. being beneficial for local use but damaging to ecosystem services and agriculture), are serious factors deterring the overall biological control effort. Here, using historical records and field surveys, we examine the invasion history, spread, impacts, and management of C. odorata in West Africa and make recommendations for the sustainable management of C. odorata in the region.     

双季稻田冬季种植模式对土壤有机碳和碳库管理指数的影响

为探讨冬季覆盖作物还田对稻田土壤碳库的影响,通过冬季种植油菜、紫云英、黑麦草、马铃薯,并以冬闲为对照进行大田试验,测定了不同冬季作物模式下早稻和晚稻的土壤有机碳、活性有机碳含量,并计算了稳态碳、碳库活度、活度指数、碳库指数和土壤碳库管理指数.结果表明:冬季作物还田增加了土壤有机碳含量,早稻和晚稻后的土壤有机碳含量比对照分别提高了1%～8%和3%～18%;油菜、黑麦草和紫云英还田均促进了土壤活性有机碳含量的增加,早稻后增加16.2%～84.2%,晚稻后增加24.4%～28.1%;冬季作物还田增加了土壤碳库管理指数,增加幅度为1.4%～41.8%.综上所述,冬种作物还田有利于提高土壤的固碳效应,并提升土壤质量,以种植黑麦草、紫云英的综合效果较佳.     

基于地理探测器的中国农业生态效率时空分异及其影响因素

研究农业生态效率的时空分异及其影响因素对实现中国农业生态高质量发展具有重要意义。基于2000—2018年中国30个省/区/市的面板数据,采用超效率SBM模型测算省际农业生态效率,在时间序列、空间可视化及趋势面分析揭示农业生态效率时空演变规律的基础上,进一步利用地理探测器模型识别影响农业生态效率空间分异的主导因子及其交互作用。结果表明: 2000—2018年,中国农业生态效率整体呈现稳定上升的趋势,但仍然处于较低水平,存在较大提升空间;中国农业生态效率具有显著的空间分异特征,总体上呈现出东西部地区较高、而中部地区较低的空间分布格局;中国农业生态效率的空间分异受到农业资源禀赋、社会经济、自然生态环境等多种因素的影响,不同因子对农业生态效率空间分异的影响存在明显差异且因子间交互作用会增强其空间分异。综上,要关注农业生态效率时空分异的主导因子,并注重区域间的协同合作,以实现农业的高质量发展。     

How landscape scale changes affect ecological processes in conservation areas: external factors influence land use by zebra (Equus burchelli) in the Okavango Delta

Most large‐bodied wildlife populations in sub‐Saharan Africa only survive in conservation areas, but are continuing to decline because external changes influence ecological processes within reserves, leading to a lack of functionality. However, failure to understand how landscape scale changes influence ecological processes limits our ability to manage protected areas. We used GPS movement data to calculate dry season home ranges for 14 zebra mares in the Okavango Delta and investigated the effects of a range of landscape characteristics (number of habitat patches, mean patch shape, mean index of juxtaposition, and interspersion) on home range size. Resource utilization functions (RUF) were calculated to investigate how specific landscape characteristics affected space use. Space use by all zebra was clustered. In the wetter (Central) parts of the Delta home range size was negatively correlated with the density of habitat patches, more complex patch shapes, low juxtaposition of habitats and an increased availability of floodplain and grassland habitats. In the drier (Peripheral) parts of the Delta, higher use by zebra was also associated with a greater availability of floodplain and grassland habitats, but a lower density of patches and simpler patch shapes. The most important landscape characteristic was not consistent between zebra within the same area of the Delta, suggesting that no single foraging strategy is substantially superior to others, and so animals using different foraging strategies may all thrive. The distribution and complexity of habitat patches are crucial in determining space use by zebra. The extent and duration of seasonal flooding is the principal process affecting habitat patch characteristics in the Okavango Delta, particularly the availability of floodplains, which are the habitat at greatest risk from climate change and anthropogenic disturbance to the Okavango's catchment basin. Understanding how the factors that determine habitat complexity may change in the future is critical to the conservation of large mammal populations. Our study shows the importance of maintaining flood levels in the Okavango Delta and how the loss of seasonal floodplains will be compounded by changes in habitat configuration, forcing zebra to change their relative space use and enlarge home ranges, leading to increased competition for key resources and population declines.     

PICCO在重型颅脑损伤患者容量管理中的临床应用价值研究

目的:探讨脉搏指数连续心输出量(PICCO)技术在重型颅脑损伤患者液体管理中的临床应用价值。方法:回顾性分析重型颅脑损伤患者46例(男性27例,女性19例),以应用PICCO技术监测血流动力学指标指导液体管理的患者为治疗组(n=26),未应用PICCO技术指导液体管理的患者为对照组(n=20)。比较两组患者的日平均液体量、格拉斯哥昏迷评分(GCS)、急性生理与慢性健康评分(APACHE II)、肺水肿发生率、住院时间、住院总费用以及治疗6个月后的格拉斯哥预后评分(GOS)、生存率、颅脑损伤恢复良好率。结果:治疗期间,治疗组的GCS评分以及APACHEII评分均优于对照组,而治疗组的住院总费用高于对照组,但差异并无统计学意义(P0.05)。治疗组的日平均液体量、肺水肿发生率及住院时间均明显少于对照组,差异有统计学意义(P0.05)。治疗6个月后,治疗组患者的GOS评分、生存率和颅脑损伤恢复良好率均高于对照组,但差异亦无统计学意义(P0.05)。结论:应用PICCO技术监测血流动力学指标指导重型颅脑损伤患者的容量管理可在一定程度上缩短危重患者的住院时间并降低肺水肿的发生率,但并不能明显改善患者的预后。     

武汉市石榴红农场休闲景观的游憩价值和存在价值估算

都市休闲农业将传统农业与旅游业结合,利用农田景观、自然生态及环境资源,融合农业生产、农村文化及农家生活等人文景观,为人们提供休闲、娱乐和游憩等多重功能.价值估算在对武汉市石榴红农场及182位样本游客调查的基础上,应用旅游成本法和条件价值评估法估算休闲农地景观的游憩价值和存在价值.研究结果表明:(1)从传统的种植单位转型为以休闲度假、农事体验、农业观光为主的农业园区,石榴红休闲农场的经营效益明显,单位用地效益较传统蔬菜种植收益 (22990.26元/(hm2·a)) 净增1.6倍,但其带给消费者的更多的是目前无法通过市场配置的非市场价值.(2)利用TCM评价出石榴红农场2006年的总游憩价值在5057.99×104元,人均消费者剩余(consumer surplus, CS)2809.99元,约为游客平均游玩费用的36.71倍;农地景观单位游憩价值334905元/(hm2·a),是休闲农业经济产值(60000元/ (hm2·a))的5.58倍,游憩价值是农地景观价值构成中的重要组成.(3)从游客的支付意愿(willingness to pay, WTP)出发,应用CVM估算出石榴红休闲农地景观保存价值达117.92×104元/a,土地年均存在价值7808元/hm2.(4)农地景观的游憩价值及存在价值等非市场效益显著,然而在现行资源价值核算体系中却往往因缺失交易机制而被遗漏,意味着在土地分配决策与消费实践中,如果只单纯考虑经济产值,土地用途转换过程中将造成大量的社会福利损失.     

水稻主要病虫综合防治专家系统—系统外壳的研制

按照国家八五项目要求,以水稻病虫害管理知识为背景,笔者构建了水稻主要病虫综防专家系统外壳（ESRIPM）．并初步建立了珠江三角洲稻区主要害虫综合防治专家系统,系统中提出一种知识的组织方法,成功地把模型引入专家系统中．本系统具有知识编辑、咨询、专家系统;系统维护、4个一级子系统,系统中已装入三化螟,稻飞虱,稻纵卷叶螟等害虫综防管理的知识,并通过调试．本系统采用下拉式菜单,人机界面友好,操作简单．此专家系统外壳也适用建立其它各种害虫管理的专家系统．     

土壤健康的生物学表征与调控

如何有效判定土壤健康状态是实现农业绿色发展的基本问题。在现有的土壤健康评价体系中,很少考虑土壤生物在维持土壤健康方面的作用。基于此,本文论述了土壤健康的内涵,从土壤生物健康的角度,总结了土壤健康的生物学表征指标,阐述了土壤微生物、土壤酶活性、土壤微食物网及蚯蚓对土壤健康的指示作用。基于上述生物指标,从作物和土壤管理等方面探讨了不同农田管理措施对土壤健康状况的调控途径,并对土壤生物健康的未来发展趋势进行了展望。本文旨在增强科学家和决策者对维护土壤生物健康的认识,充分发挥土壤生物在生态系统服务中的重要作用。