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1.
The parental food compensation hypothesis suggests that parents may compensate for the negative effects of parasites on chicks by increased food provisioning. However, this ability differs widely among host species and may also depend on ecological factors such as adverse weather conditions and habitat quality. Although weed management can improve habitat quality, management measures can bring about a temporary decrease in food availability and thus may reduce parents’ ability to provide their nestlings with enough energy. In our study we investigated the interaction of parasitism and weed management, and the influence of climate on feeding rates in a Darwin’s tree finch species, which is negatively impacted by two invasive species. The larvae of the invasive parasitic fly Philornis downsi ingest the blood and body tissues of tree finch nestlings, and the invasive Blackberry Rubus niveus affects one of the main habitats of Darwin’s tree finches. We compared parental food provisioning of the Small Tree Finch Camarhynchus parvulus in parasitized and parasite‐free nests in three different areas, which differed in invasive weed management (no management, short‐term and long‐term management). In a parasite reduction experiment, we investigated whether the Small Tree Finch increases food provisioning rates to nestlings when parasitized and whether this ability depends on weed management conditions and precipitation. Our results provide no evidence that Small Tree Finches can compensate with additional food provisioning when parasitized with P. downsi. However, we found an increase in male effort in the short‐term management area, which might indicate that males compensate for lower food quality with increased provisioning effort. Furthermore, parental food provisioning was lower during rainfall, which provides an explanation for the negative influence of rain on breeding success found in earlier studies. Like other Darwin’s finches, the Small Tree Finch seems to lack the ability to compensate for the negative effects of P. downsi parasitism, which is one explanation for why this invasive parasite has such a devastating effect on this host species.  相似文献   
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荔枝蝽Tessaratoma papillosa是荔枝和龙眼生产中的重要害虫,在中国南方及东南亚地区危害严重。该虫以若虫及成虫吸食寄主植物的嫩芽、嫩梢、花穗和幼果,成虫和3龄以上若虫是传播龙眼鬼帚病病原体的传病介体昆虫。本文综述了近60年来国内荔枝蝽的研究情况,旨在为广大科研工作者提供更详尽的荔枝蝽研究现状,以期为该虫的深入研究及绿色防控技术的研发提供参考。荔枝蝽为不完全变态昆虫,一年发生1代,若虫期80 d左右,成虫寿命为203~371 d,单雌产卵总量190粒左右,在习性上表现出明显的聚集性、趋光性、趋色性和趋嫩梢性。近年来,通过荔枝蝽触角感受器分类及分布观察,触角转录组数据测定和分析,臭腺解剖观察以及臭腺分泌物组分分析,对该虫触角和臭腺两大器官组织已有较深入研究及了解。目前,荔枝蝽的发生期主要通过卵巢发育分级法进行预测预报,对该虫的防治仍然是以化学防治为主,农业防治、物理防治和生物防治为辅的策略。其中,荔枝蝽生物防控技术研究报道最多,主要集中在天敌的保护利用和生物源农药的应用。由于荔枝蝽虫源的季节性制约和发生为害地域限制,对该虫的研究进展缓慢,深层次的研究较少,且所涉及到的研究领域也比较窄。从组学、分子生物学、细胞生物学等多角度探明荔枝蝽对寄主植物的选择机制,与寄主植物、天敌及共生菌间的互作关系,以及抗药性机理等,将为荔枝蝽绿色防治技术带来新思路。  相似文献   
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青海东部人工生态公益林近自然经营的林分结构调整   总被引:1,自引:0,他引:1  
王琼琳  王文义  林莎  曹志  陈琪  贺康宁 《生态学报》2021,41(12):5004-5015
依据研究区5种典型人工林近自然状况,以人工生态公益林的近自然经营管理为目标,提出林分结构调整策略与方法。主要从林分结构、物种组成、年龄及枯死木几个方面考虑选取了垂直结构、水平结构、草本盖度及其多样性、天然更新、物种多样性、组成系数、直径分布、枯木比例、健康木比例10个指标,应用基于单位圆的π值法则,采取定性与定量相结合的方法,对5种林分的近自然状态做出评价并依据评价结果提出相应改造措施。青海云杉-白桦混交林(ωPB=0.4786)属于远近自然林分,此类林分在密度合理的情况下无需过多人为抚育;青杨-白桦混交林(ωBP=0.2664)属于近人工林,此类林分以伐除病虫害严重的青杨、调整密度和补植青海云杉为主;青海云杉-青杨混交林(ωPP=0.2283)属于近人工林,此类林分以伐除病虫害严重的青杨、调整密度和补植白桦为主;青海云杉-落叶松混交林(ωPL=0.1872)属于人工林,此类林分以调整密度和补植白桦为主;青海云杉纯林(ωP=0.0190)属于人工林,此类林分以调整密度和营造杉桦混交林为主。通过近自然度评价与分析,为当地近自然经营提供了直观可靠的依据。在进行林分结构调整时,首先通过伐除干扰木来调整林分密度,其次要营造针阔混交林分,其中以青海云杉和白桦混交林为主要目标林分。  相似文献   
5.
耕作方式对潮土土壤团聚体微生物群落结构的影响   总被引:1,自引:0,他引:1  
为探究不同耕作方式对潮土土壤团聚体微生物群落结构和多样性的影响,采用磷脂脂肪酸(PLFA)法测定了土壤团聚体中微生物群落。试验设置4个耕作处理,分别为旋耕+秸秆还田(RT)、深耕+秸秆还田(DP)、深松+秸秆还田(SS)和免耕+秸秆还田(NT)。结果表明:与RT相比,DP处理显著提高了原状土壤和>5 mm粒级土壤团聚体中真菌PLFAs量和真菌/细菌,为真菌的繁殖提供了有利条件,有助于土壤有机质的贮存,提高了土壤生态系统的缓冲能力;提高了5~2 mm粒级土壤团聚体中细菌PLFAs量,降低了土壤革兰氏阳性菌/革兰氏阴性菌,改善了土壤营养状况;提高了<0.25 mm粒级土壤团聚体中微生物丰富度指数。总的来说,深耕+秸秆还田(DP)对土壤团聚体细菌和真菌生物量有一定的提高作用,并且在一定程度上改善了土壤团聚体微生物群落结构,有利于增加土壤固碳能力和保持土壤微生物多样性。冗余分析结果表明,土壤团聚体总PLFAs量、细菌、革兰氏阴性菌和放线菌PLFAs量与土壤有机碳相关性较强,革兰氏阳性菌PLFAs量与总氮相关性较强。各处理较大粒级土壤团聚体微生物群落主要受碳氮比、含水量、pH值和团聚体质量分数的影响,较小粒级土壤团聚体微生物群落则主要受土壤有机碳和总氮的影响。  相似文献   
6.
草地利用移动性的丧失导致生态系统退化,是草地放牧生态学领域兴起的主导性学说。在我国,草地利用移动性的丧失不仅是政策变化导致的,更是众多自然和社会因素叠加演进的结果。草地利用移动性的重建对于中国草地恢复和可持续性管理具有重要意义,但是很难通过恢复传统或季节性轮牧的途径实现。我们可以依托智能围栏、牲畜智能可穿戴设备以及草地生产力无人机快测等新型放牧管理技术,在我国不同气候区域、不同类型草地,因地制宜地发展新型草地移动性管理模式,进而重建“草地利用的移动性”。新型轮牧模式还应与草畜平衡、牲畜补饲以及土壤养分补充等重要生态草牧业措施结合,确保我国草地资源的高效可持续利用。  相似文献   
7.
全球环境基金(GEF)作为《生物多样性公约》财务机制的运行主体, 已在全球范围内实施了7个周期, 各国在执行GEF项目期间, 遇到了可持续性不强、项目设计方案复杂、期望过高等挑战。作为GEF的国际实施机构, 联合国开发计划署(UNDP)与中国政府合作, 针对各项挑战, 采取综合应对措施, 优化设计与实施的生物多样性项目取得了系列成就, 这些项目的实施是落实爱知生物多样性目标和《2011-2020年生物多样性战略计划》的有效实践并提供了成功范例。这些应对策略与成就包括: (1)撬动了中国政府5-10倍的配套资金用于生物多样性相关工作, 推动生物多样性在中国各级政府的主流化, 使得财务、制度和环境的可持续得以实现。项目贡献于国家宏观战略规划和五年计划的制订、完善法律法规、探索融资机制、推进政策导向等方面, 并将生物多样性纳入国家重要议程, 使生态文明的理念发挥政策引领作用。(2)项目从设计到执行, 充分征询利益相关者的意见, 目标的设定明智, 确保了项目的实施成效。(3)借鉴相关国家成功经验, 结合中国实际开展了诸多创新和示范。(4)提供培训、教育和广泛交流, 综合提升了生物多样性领域相关机构和人员的能力, 对于增强技术、管理、协调、协作等领域的软实力和巧实力发挥了桥梁和纽带作用。(5)利用各种窗口和平台, 广泛开展宣传推广、研讨交流等, 提高了公众对生物多样性的认知, 为长期践行可持续发展战略奠定群众基础。本文结合UNDP作为国际实施机构与相关部委和省级及地方政府共同实施的GEF生物多样性项目实践, 总结了项目的成就与经验, 期望为全球相关项目设计和实施以及2020年后全球生物多样性框架的制定提供借鉴, 以共同实现“到2050年与自然和谐相处”的愿景。  相似文献   
8.
Exotic perennial grasses (EPGs) pose a significant risk to native communities globally. With over 2,200 species in Australia, understanding which characteristics enable high threat invasions, and comparing between functionally similar EPGs, can help prioritise species management. We developed a framework of risk and used the literature to rank 21 EPGs considered a threat to plant communities in New South Wales, while also evaluating the reliability of information currently available. Characteristics were scored within five broad categories that distinguish invasiveness: Arrival, Establishment, Persistence, Impact and Distribution. These included aspects of reproductive biology, competitive ability and environmental tolerance. The risk assessment was effective in assessing key characteristics of invasion. EPGs with an economic benefit (trade‐off species) were more likely to have reliable research and frequently ranked as high‐risk invaders in natural habitats due to the overlap of characteristics important in invasion with those considered important in agriculture. Lack of formal scientific research hindered assessment for some species, and some traits had been poorly assessed in the literature. High uncertainty was associated with key characteristics for Establishment, Persistence and Impact. Uncertainty in key characteristics revealed a need for improved integration of less formal research validated by more formal scientific research. This may lead to more informed decisions in the management of EPGs in native habitats and assist in early control of EPGs not yet assessed.  相似文献   
9.
Question: An ancient woodland site with a long history of coppicing and heavy grazing was protected from domesticated stock in 1955. Results of a vegetation-monitoring experiment were subsequently published in 1983. This study followed up the original research to investigate whether observed trends were as predicted. These included a shift in tree species composition in favour of shade-tolerant species, beech (Fagus sylvatica) and rowan (Sorbus aucuparia), at the expense of light-demanding birch (Betula spp.) and oak (Quercus petraea agg.), and progress towards a typical woodland ground flora. Location: Peak District National Park, United Kingdom. Methods: The mixed oak–birch woodland was re-surveyed in 2011. Two enclosures (1955 and 1980s) and an unenclosed control area were investigated. Overstorey structure and composition was assessed by measuring canopy openness and the girths of all trees and saplings. Herb layer species composition was also recorded in 28 vegetation plots. Results: We demonstrated a progressive decline in the number of mature oaks and birch in the old enclosure although they still regenerated successfully. Only a few individuals of beech and rowan appeared. Herb layer species composition differed between the subareas but since the 1980s, the temporal change in the old enclosure was negligible. The new enclosure followed a similar pattern in both canopy and herb layer as observed in the early years in the old enclosure. However, the control subarea had no regeneration of woody species and limited ground flora. Conclusions: After nearly 60 years, the replacement of light-demanding dominants by shade-tolerant trees was still limited, probably by low pH and stable light conditions. The findings are pertinent to the impacts of large herbivore grazing (domestic stock or wild) on woodland dynamics.  相似文献   
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