The effectiveness of flower strips and hedgerows on pest control,pollination services and crop yield: a quantitative synthesis

Floral plantings are promoted to foster ecological intensification of agriculture through provisioning of ecosystem services. However, a comprehensive assessment of the effectiveness of different floral plantings, their characteristics and consequences for crop yield is lacking. Here we quantified the impacts of flower strips and hedgerows on pest control (18 studies) and pollination services (17 studies) in adjacent crops in North America, Europe and New Zealand. Flower strips, but not hedgerows, enhanced pest control services in adjacent fields by 16% on average. However, effects on crop pollination and yield were more variable. Our synthesis identifies several important drivers of variability in effectiveness of plantings: pollination services declined exponentially with distance from plantings, and perennial and older flower strips with higher flowering plant diversity enhanced pollination more effectively. These findings provide promising pathways to optimise floral plantings to more effectively contribute to ecosystem service delivery and ecological intensification of agriculture in the future.     

基于组合评价法的湖南省农业可持续发展区域分异

从农业资源与环境、农业生产与经济、农业人口与社会3个评价维度构建了区域农业可持续发展指标体系, 运用主成分分析法、熵值法、模糊Borda法、因子分析法及聚类分析法和GIS技术, 通过组合评价方法定量研究湖南省农业可持续发展区域分异现状。结果表明: 湖南省农业可持续发展在区域上总体呈现出不平衡的发展状态, 农业可持续发展综合水平以长株潭城市群为核心, 由东至西递减; 农业人口与社会可持续发展水平南北低中部高, 东部强西部弱; 农业生产与经济可持续发展水平围绕湘北洞庭湖农业区和湘南农业综合区向外围递减; 农业资源与环境可持续发展水平表现为一横两纵优势带和南北两个落后圈。     

Total ecosystem carbon stocks at the marine‐terrestrial interface: Blue carbon of the Pacific Northwest Coast,United States

The coastal ecosystems of temperate North America provide a variety of ecosystem services including high rates of carbon sequestration. Yet, little data exist for the carbon stocks of major tidal wetland types in the Pacific Northwest, United States. We quantified the total ecosystem carbon stocks (TECS) in seagrass, emergent marshes, and forested tidal wetlands, occurring along increasing elevation and decreasing salinity gradients. The TECS included the total aboveground carbon stocks and the entire soil profile (to as deep as 3 m). TECS significantly increased along the elevation and salinity gradients: 217 ± 60 Mg C/ha for seagrass (low elevation/high salinity), 417 ± 70 Mg C/ha for low marsh, 551 ± 47 Mg C/ha for high marsh, and 1,064 ± 38 Mg C/ha for tidal forest (high elevation/low salinity). Soil carbon stocks accounted for >98% of TECS in the seagrass and marsh communities and 78% in the tidal forest. Soils in the 0–100 cm portion of the profile accounted for only 48%–53% of the TECS in seagrasses and marshes and 34% of the TECS in tidal forests. Thus, the commonly applied limit defining TECS to a 100 cm depth would greatly underestimate both carbon stocks and potential greenhouse gas emissions from land‐use conversion. The large carbon stocks coupled with other ecosystem services suggest value in the conservation and restoration of temperate zone tidal wetlands through climate change mitigation strategies. However, the findings suggest that long‐term sea‐level rise effects such as tidal inundation and increased porewater salinity will likely decrease ecosystem carbon stocks in the absence of upslope wetland migration buffer zones.     

Threshold responses of riverine fish communities to land use conversion across regions of the world

The growing human enterprise has sparked greater interest in identifying ecological thresholds in land use conversion beyond which populations or communities demonstrate abrupt nonlinear or substantive change in species composition. Such knowledge remains fundamental to understanding ecosystem resilience to environmental degradation and informing land use planning into the future. Confronting this challenge has been largely limited to inferring thresholds in univariate metrics of species richness and indices of biotic integrity and has largely ignored how land use legacies of the past may shape community responses of today. By leveraging data for 13,069 riverine sites from temperate, subtropical, and boreal climate zones on four continents, we characterize patterns of community change along diverse gradients of urbanization and agricultural land use, and identity threshold values beyond which significant alterations in species composition exists. Our results demonstrate the apparent universality by which freshwater fish communities are sensitive to even low levels of watershed urbanization (range of threshold values: 1%–12%), but consistently higher (and more variable) levels of agricultural development (2%–37%). We demonstrated that fish community compositional thresholds occurred, in general, at lower levels of watershed urbanization and agriculture when compared to threshold responses in species richness. This supports the notion that aggregated taxon‐specific responses may better reflect the complexity of assemblage responses to land use development. We further revealed that the ghost of land use past plays an important role in moderating how current‐day fish communities respond to land use intensification. Subbasins of the United States experiencing greater rates of past land use change demonstrated higher current‐day thresholds. Threshold responses of community composition, such as those identified in our study, illustrate the need for globally coordinated efforts to prioritize country‐specific management and policy initiatives that ensure that freshwater fish diversity is not inevitably lost in the future.     

Defining CO2 and O2 syndromes of marine biomes in the Anthropocene

Research efforts have intensified to foresee the prospects for marine biomes under climate change and anthropogenic drivers over varying temporal and spatial scales. Parallel with these efforts is the utilization of terminology, such as ‘ocean acidification’ (OA) and ‘ocean deoxygenation’ (OD), that can foster rapid comprehension of complex processes driving carbon dioxide (CO₂) and oxygen (O₂) concentrations in the global ocean and thus, are now widely used in discussions within and beyond academia. However, common usage of the terms ‘acidification’ and ‘deoxygenation’ alone are subjective and, without adequate contextualization, have the potential to mislead inferences over drivers that may ultimately shape the future state of marine ecosystems. Here we clarify the usage of the terms OA and OD as global, climate change‐driven processes and discuss the various attributes of elevated CO₂ and reduced O₂ syndromes common to coastal ecosystems. We support the use of the existing terms ‘coastal acidification’ and ‘coastal deoxygenation’ because they help differentiate the sometimes rapid and extreme nature of CO₂ and O₂ syndromes in coastal ecosystems from the global, climate change‐driven processes of OA and OD. Given the complexity and breadth of the processes involved in altering CO₂ and O₂ concentrations across marine ecosystems, we provide a workflow to enable contextualization and clarification of the usage of existing terms and highlight the close link between these two gases across spatial and temporal scales in the ocean. These distinctions are crucial to guide effective communication of research within the scientific community and guide policymakers responsible for intervening on the drivers to secure desirable future ocean states.     

微藻源生物刺激剂的制备及在设施农业中的应用

化肥和农药的过量使用导致的农业面源污染已经成为我国环境污染的重要组成部分,对农业绿色高效安全生产及设施农业带来了巨大挑战。寻找新型的传统化肥替代品、提高化肥使用效率及保护生态环境是亟待解决的重大问题。生物刺激剂是具有调控植物生长作用的成分和(或)微生物的统称,用于农业生产,可改善土壤理化性质与群落微生物,能促进作物的代谢与生长,增强对营养物质的吸收和利用,提升作物抗逆能力及提高作物产量与产品品质。微藻体内具有结构新颖、功能独特的天然活性物质,是制备新型生物刺激剂的理想来源。微藻用于环境治理的同时,可获得足量的微藻生物质来制备生物刺激剂,从而达到治理环境、降低成本及提质增效的目的。就微藻源生物刺激剂的定义及功能、微藻全细胞和天然活性物质生物刺激剂的制备、应用效果及对植物和土壤的作用原理进行综述,以期为微藻源强效生物刺激剂的规模化制备及农业生产应用奠定理论基础和提供生产实践指导。     

In-Water Bridge Construction Effects on Manatees with Implications for Marine Megafauna Species

Globally, increasing coastal development requires construction and maintenance of transportation infrastructure that affects terrestrial and aquatic ecosystems. Construction of bridges as part of transportation networks introduces a series of risks to aquatic species near construction zones. We reviewed relevant literature and obtained exemplary case studies to synthesize potential effects of bridge construction on the West Indian manatee (Trichechus manatus), a nearshore megafauna species vulnerable to human activities. Stages of bridge construction including dredging, pile driving, and installation and assembly of bridge components each involve potential direct and indirect effects on manatees. Direct effects such as vessel interactions, entanglement or ingestion, and entrainment may result in acute physical injury or mortality. Indirect effects from construction such as habitat obstruction or degradation and increased noise from construction activities can alter behavior and intraspecies communication and reduce access to essential resources. Some effects of construction may be immediately difficult to quantify, but cumulative effects through time can result in major habitat and species loss. To prevent large-scale negative effects of construction on manatees and other aquatic species, use and evaluation of mitigation strategies should be implemented pre-, during, and post-construction. As the global human population increasingly occupies coastal zones, effective planning of coastal development, including bridge and other in-water construction, will be essential to support conservation and recovery efforts for manatees and other species at risk in these areas. © 2021 The Wildlife Society.     

Reducing Biotic and Abiotic Land‐Use Legacies to Restore Invaded,Abandoned Citrus Groves

Land‐use legacies associated with agriculture, such as increased soil fertility and elevated soil pH, promote invasions by non‐native plant species on former agricultural lands. Restoring natural soil conditions (i.e. low fertility and low pH) may be an effective, long‐term method to control and reduce the abundance of non‐native and ruderal species that invade abandoned agricultural lands. In this study, we examined how soil manipulation treatments of lowering soil fertility with carbon additions and lowering soil pH by applying sulfur affect non‐native and ruderal native plant species abundance in two former citrus groves in central Florida. Non‐native plant biomass was removed by one of two methods (tilling or topsoil removal), and was combined with a soil amendment of sulfur, carbon, sulfur + carbon, or none. The biomass removal treatments significantly decreased non‐native abundance, with topsoil removal as the most effective. Carbon additions did not affect soil fertility or vegetation. Sulfur and sulfur + carbon additions significantly decreased soil pH in both groves for at least 1 year post‐treatment; however, we did not see a significant vegetation response. Overall, our results suggest that removing vegetation by tilling and topsoil removal is an effective method for reducing non‐target species cover. Although we did not see a response of vegetation to our treatments, we were able to restore the initial soil characteristics, which can be a first step toward complete restoration.