景观空间异质性对生态系统服务形成与供给的影响

景观空间异质性与生态系统服务的关系极为密切,适当调整景观空间异质性有助于生态系统服务的持续形成与稳定供给。研究景观空间异质性和生态系统服务形成与供给之间的相互影响作用及响应机制具有重要的理论与现实意义,是保护生物多样性、管理生态系统服务与优化景观空间配置的基础。现有研究大多在不同尺度上探讨了景观格局与生态过程或生态系统服务间的相互影响关系,而缺乏景观格局-生态过程-生态系统服务三者间有效联结等方面的研究。景观空间异质性是怎样直接或间接地作用于生态系统服务形成与供给的,目前还没有一个较为明确的解释。因此,通过分析国内外文献,回顾了景观格局或景观空间异质性与生态系统服务之间关系的研究进展、研究内容和研究方法;从景观组成、景观构型的变化入手,讨论了景观空间异质性对生态系统服务形成与供给的影响及其强度,并认为景观组成异质性变化能够直接影响生态系统服务,而景观构型异质性变化会通过改变生态过程而间接影响生态系统服务;阐述了景观空间异质性在影响生态系统服务形成与供给的同时,也使生态系统服务在空间上产生了异质性分布,并从自然因素和人为因素两个方面对其进行解释;强调了尺度问题在景观空间异质性与生态系统服务研究中的重要性;最后,明确了对生态系统服务形成与供给的景观空间异质性影响研究不仅有助于生态系统服务的维持与调节,也能更深层次地揭示其中的生态学意义。     

Hotspot and relationship identification in multiple landscape services: A case study on an area with intensive human activities

The identification of the relationships between different landscape services is important in social–ecological complex systems, especially in areas with intensive human activities. In this paper, Beijing and its peripheral regions are taken as a case study to calculate and map the intensities of five classic landscape services including material production, carbon storage, soil retention, habitat conservation, and population support based on grid maps. Overlap and correlation analyses were used to identify multiple service hotspots and the relationships between landscape services. The results show that (1) landscape services have spatial heterogeneity: high-intensity area of material production and population support is on the southeast plains of this region and high-intensity area of soil retention and habitat conservation is on the northwest; (2) approximately 96.03% of the region can provide at least one type of landscape services, whereas approximately three-quarters of the area provide multiple services, with the multiple service hotspots surrounding Beijing and Tianjin; (3) correlations exist between all pairs of landscape services, but strong correlations (correlation coefficient >0.5 or <−0.5) exist between four pairs, which are soil retention and habitat conservation (0.672), soil retention and population support (−0.613), habitat conservation and population support (−0.540), and material production and population support (0.529); (4) the services can be divided into two trade-off service bundles: the “natural” bundle, which contains carbon storage, soil retention, and habitat conservation, and the “artificial” bundle, which contains material production and population support. Only 4.19% of the area in this region contains these service bundles simultaneously. Finally, an improved understanding of the relationships between services was illustrated, and the importance of such services was highlighted for decision-makers and stakeholders.     

农业景观异质性对生物多样性与生态系统服务的影响研究进展

农业景观是人类生活所需资料的最主要来源地,农业景观及其提供的生物多样性和生态系统服务是影响人类福祉的最主要因素之一。系统梳理了景观异质性变化对生物多样性和生态系统服务影响的相关研究,总结指出:(1)农业景观格局变化会强烈的影响着区域生物多样性和生态系统服务,但总体上更关注了空间异质性,对于时间和功能异质性的研究仍需加强;(2)尺度效应、大尺度上景观背景的差异、种间差异、营养级联效应等会对景观异质性和生物多样性、生态系统服务间的关系产生显著的、综合的、交互的影响效应。未来区域农业景观中如何通过景观构建和管理措施的施行来确保生物多样性与生态系统服务供给的持续稳定仍需进一步加强以下内容的研究:景观异质性变化在时间上和功能上的影响效应及其阈值的探讨;跨尺度、多因素、多物种类群与多生态系统服务的综合及其交互作用;不同生物类群和不同生态系统服务间的权衡;景观异质性提高与有效生境面积下降及其引起的生物随机丧失间的权衡等问题。     

陕北黄土高原景观格局对生态系统服务权衡关系的影响

揭示景观格局对生态系统服务权衡关系的作用机理对于开展多种ES的可持续管理具有重要意义。在评估陕北黄土高原2000—2020年粮食供给、水源涵养、土壤保持、生境质量和景观美学等5种生态系统服务的基础上,利用相关系数和均方根误差测度其权衡强度,结合R指数模型、变异划分法定量表达景观组分和景观配置对生态系统服务权衡关系的影响差异。结果表明：1)2000—2020年陕北黄土高原5种生态系统服务整体呈上升趋势,空间上粮食供给北高南低,水源涵养、土壤保持、生境质量和景观美学则为南高北低的分布格局;2)粮食供给与其他4种服务为权衡关系,而水源涵养、土壤保持、生境质量和景观美学之间呈协同关系;3)斑块丰富度对各组权衡关系具有正向影响,而斑块面积和景观百分比则具有负向影响;4)景观组分对各组权衡关系的单独贡献度高于景观配置,多数情况下,权衡关系更多由组分和配置的联合作用主导。研究从景观管理角度为改善陕北黄土高原生态系统服务间的权衡关系、提升ES的潜在供给能力提供了科学依据。     

四川盆地多重生态系统服务景观指数评价与服务簇识别

明确多重生态系统服务与生态系统服务簇的空间格局对于维持区域生态安全格局与可持续发展至关重要。在评估四川盆地2015年6种生态系统服务的基础上,计算了表征综合水平的多重生态系统服务景观指数;进而分析了生态系统服务间权衡与协同关系;并基于K-均值聚类法识别了研究区内生态系统服务簇的空间格局。研究结果表明：（1）研究区的多重生态系统服务景观指数平均值达到3.12,同时具有明显的空间分异性,整体上呈现出东南高西北低的空间分布格局,高值区主要分布于川东平行岭谷区,以林、草地为主的区域最高,城市建成区及其邻近地区最低。（2）6种生态系统服务空间异质性显著,且不同服务间协同与权衡关系并存,其中碳汇、生境质量和水土保持服务三者间的协同关系显著,碳汇、生境质量和水土保持服务与娱乐和粮食供给服务间的权衡关系均较强;产水服务与其他各项服务间的权衡与协同关系均较弱。（3）四川盆地可划分为文化旅游、食物供给、生态保育和多功能复合均衡型4种服务簇,其空间布局与内部结构分异明显。文化旅游型服务簇面积最小,面积占比为3.11%,主要分布于成都和重庆城镇及其周边地区,其提供多重生态系统服务功能的能力最弱;食物供给型服务簇主要位于成都平原、浅丘及部分河谷区域,面积约占36.23%;生态保育型服务簇主要分布于盆周山地,以林地为主导,其提供多重生态系统服务功能的能力最强,面积占比达22.61%;多功能复合均衡型服务簇分布最广,面积占比为38.04%,集中于川中、川东丘陵及平行岭谷槽谷区域。采取差异化优化措施有利于整体提升四川盆地生态系统服务能力,维护区域生态安全格局。     

Assessing regulating and provisioning ecosystem services in a contrasting tropical forest landscape

Ecosystem services are the bridge between nature and society, and are essential elements of community well-being. The Wet Tropics Australia, is environmentally and biologically diverse, and supplies numerous ecosystem services. It contributes to the community well-being of this region, Australian national economy and global climate change mitigation efforts. However, the ecosystem services in the region have rarely been assessed undermining strategic landscape planning to sustain their future flow. In this study, we attempted to: (i) assess the quantity of five regulating ecosystem services – global climate regulation, air quality regulation, erosion regulation, nutrient regulation, and cyclone protection, and three provisioning ecosystem services – habitat provision, energy provision and timber provision across rainforests, sclerophyll forests and rehabilitated plantation forests; (ii) evaluate the variation of supply of those regulating and provisioning ecosystem services across environmental gradients, such as rainfall, temperature, and elevation; (iii) show the relationships among those ecosystem services; and (iv) identify the hotspots of single and multiple ecosystem services supply across the landscape. The results showed that rainforests possess a very high capacity to supply single and multiple ecosystem services, and the hotspots for most of the regulating and provisioning ecosystem services are found in upland rainforest followed by lowland rainforest, and upland sclerophyll forest. Elevation, rainfall and temperature gradients along with forest structure are the main determinant factors for the quantity of ecosystem services supplied across the three forest types. The correlation among ecosystem services may be positive or negative depending on the ecosystem service category and vegetation type. The rehabilitated plantation forests may provide some ecosystem services comparable to the rainforest. The results demonstrated disturbance regimes (such as tropical cyclones) may have influenced the usual spatial trend of ecosystem service values. This study will assist decision makers in incorporating ecosystem services into their natural resource management planning, and for practitioners to identify the areas with higher values of specific and multiple ecosystem services.     

河流景观生态服务供给与需求/消费的互馈机制

河流景观系统孕育了人类文明,为人类社会提供类型多样的生态系统服务。其本身是一个自然景观过程和社会经济过程高度耦合的社会-生态系统,具有极高的空间异质性、时间动态和鲜明的组织尺度等级结构。当前,对河流景观系统这种特点所决定的生态系统服务供给与需求/消费互馈的机制研究不够深入,普遍缺乏从过程角度刻画生态服务供给与需求/消费互馈关系及其时空异质性和尺度特征。生态服务供给、需求和消费产生于社会-生态系统,是社会-生态耦合的纽带。阐述了河流景观生态服务供给和需求/消费的时空异质性,阐释了它们时空耦合机制和尺度特征,梳理了当前对生态服务供给、需求/消费互馈机理研究的不足。认为未来需要在社会-生态系统的框架下,从景观结构和生态过程出发,融合景观生态过程和社会过程来深入认识河流景观系统的生态服务供给与区内人类对生态服务的需求/消费之间的互馈机制。未来应重点关注：（1）河流景观结构和过程决定的生态服务供给和消费的空间分异及驱动机制;（2）河流生态服务传输的自然和人文载体及其耦合格局;（3）将生态服务需求/消费通过景观结构和生态过程对生态服务供给的反馈融入生态服务评估的方法框架,研发基于生态服务供给和需求/消费的社会-生态互馈过程模型。     

京津冀地区县域耕地景观多功能性评价

随着城镇化发展和农业产业化升级,耕地景观功能由单一的生产功能向经济功能、生态功能、文化功能拓展,耕地景观多功能性成为新的学术热点。已有研究往往侧重于探讨耕地功能的多指数耦合,缺乏耕地景观多重功能空间定量化与相互关联的分析。以京津冀地区为研究区,对耕地景观的粮食供给功能、生境维持功能、景观连通功能、土壤保持功能、景观美学功能和人口承载功能六项功能及其冷热点聚集区分别空间定量化,评价县域尺度耕地景观多功能性,并识别耕地景观多种功能的空间关联。研究结果表明,京津冀中部平原地区粮食供给功能显著,南部平原地区景观连通功能突出,燕山与太行山山脉土壤保持功能、维持生境功能最高,山前平原地带人口承载功能相对重要。2010年京津冀地区耕地景观功能总体呈现南高北低的分布格局,但功能高低值分布规律差异明显,各功能全部处于高值或低值的样本极少;耕地景观不同功能间的权衡与协同关系数量相当,景观连通功能与粮食供给功能呈现明显协同关系,而与土壤保持功能呈现较强权衡关联。     

农业景观动态对林地地表节肢动物多样性的影响

以黄河下游典型农区封丘县为研究区,在林地景观中进行地表节肢动物的观测。用物种丰富度和香农多样性指数代表物种多样性,选择代表景观背景的5个竞争模型:生境特性(H1,2012)、基质特性(H2,2012)、生境变化(H3,1984—2012)、基质变化(H4,1984—2012)和土壤-环境条件(H5,2012)从4个空间尺度上(100,250,350和500 m)进行分析,通过运用基于赤池信息量准则(Akaike information criterion,AIC)的多模型推理(Multi-model Inference,MMI)方法,在R软件里用广义线性模型(Generalized Linear Models,GLM)探究了研究区近30年(1984—2012年)景观背景变化对林地地表节肢动物多样性的影响。研究表明,不同景观背景模型对地表节肢动物多样性的影响具有尺度依赖性。在100 m的尺度下,生境特性(H1)最能够解释香农多样性和物种丰富度,但是随着尺度的增加,生境特性变化(H3)在较大(250、350 m和500 m)的尺度对物种丰富度和香农多样性影响最大,而基质特性和土壤-环境条件(H2和H5)的作用不显著。景观背景对地表节肢动物多样性的解释量达到40%。在研究区域,生境特性是表征香农多样性指数和物种丰富度的指标。     

多尺度生态系统服务的权衡关系及其对景观配置的响应——以湖北省为例

多种生态系统服务相互关系及其对景观配置响应的多尺度分析一直是生态系统服务研究的热点问题,对于厘清生态系统服务尺度效应和实现区域分级管理具有重要的意义。以湖北省为研究区域,采用遥感、土地利用类型、水文、气象、土壤等多元数据,从5 km×5 km、10 km×10 km、15 km×15 km、20 km×20 km、25 km×25 km、县域和市域等7个递增尺度分析4种生态系统服务(水源供给、碳固持、粮食生产、水质净化)对景观配置的响应关系。结果表明：(1)4种生态系统服务的空间分布具有较强的异质性,粮食生产服务的高值区与水质净化服务的低值区主要分布于湖北省中部和东部的耕地集中区域,碳固持与水源供给呈现相反的空间特征。(2)生态系统服务权衡关系的作用强度随尺度增加而减弱,而协同关系呈增加趋势;同时服务间相互作用强度的变化大于作用方向的变化。(3)景观配置对生态系统服务的影响程度在县域和市域尺度上大于格网尺度。结果反映了受尺度变化中“削峰填谷”过程的影响,景观配置对生态系统服务影响的大小和正负效应具有尺度差异性。研究结果可为区域生态系统服务分级管理和景观格局调控提供科学参考。     

Linear woodlots increase wild bee abundance by providing additional food sources in an agricultural landscape

1. Mid-field woodlots play an important role in maintaining biodiversity in agricultural landscapes. However, it is not clear whether non-linear or linear woodlots are most beneficial for wild bee conservation.
2. We assessed the attractiveness of two common types of woodlots in an agricultural landscape in northern Poland (non-linear and linear: 7 and 9 sites, respectively) in terms of wild bee abundance, species richness, and functional diversity.
3. Linear habitats had higher abundance of wild bees. However, woodlot type did not affect wild bee species composition or functional trait composition. Species composition responded significantly to measures of syntaxonomic heterogeneity and landscape heterogeneity. Woodlot area, landscape context (isolation and landscape heterogeneity), and syntaxonomic heterogeneity explained most of the differences among habitats (non-linear vs. linear) in wild bee abundance and species richness, regardless of the habitat type. The higher attractiveness of linear woodlots was due to increased food availability in the herbaceous layer in the spring–summer (June) and summer (July–August) periods.
4. Linear woodlots have the potential to be used as tools for integrating agricultural production with biodiversity conservation and ecosystem services.

     

黄淮平原农业景观不同生境鸟类多样性特征及年际动态

鸟类是地球生物多样性中的重要组成部分,在生态系统功能和服务中发挥着重要作用,是生态环境变化的重要指示物种。农业景观中的食虫鸟类提供了重要的虫害控制服务。当前,农业景观中鸟类多样性丧失加剧,为探讨鸟类多样性在各生境以及年际间的变化,以黄淮平原为研究区,在河流、湖泊、农田、村庄等生境中共设置20个样点。于2016-2019年连续4年在繁殖期采用样线法对鸟类进行多样性调查。调查结果显示：（1）共发现22922只个体,分属14目,38科,53属。从区系分布来看,各生境各年间均以广布种为主;从生态类群来看,鸣禽占绝对优势;从居留型来看,留鸟所占比例最高。（2）在食性组成上,从物种丰富度看,食虫鸟类有57种,约占总物种数的77%;从个体数来看,杂食性鸟类占比超52%。（3）物种丰富度、多样性和均匀度指数最高值均出现在湖泊或河流生境中。（4）鸟类群落相似性分析显示,各生境间鸟类群落均为中等相似程度;鸟类物种丰富度波动幅度在农田和村庄中呈逐年上升趋势。（5）物种多样性加性拆分分析显示,在生境尺度上,局地的α多样性是生物多样性的最重要组成,而从整个研究区来看,生境间的差异则更为重要。造成鸟类多样性时空差异的原因复杂多样,而生境异质性的增加和水域的存在对提高鸟类多样性是具有积极作用的。调查中超过77%的物种和40%的个体均为食虫鸟类,应当充分重视鸟类为区域农业景观提供的虫害控制服务。本研究可为区域鸟类多样性保护及鸟类提供的生态系统服务的提升管理提供理论基础和科学依据。     

Spatial heterogeneity in landscape structure influences dispersal and genetic structure: empirical evidence from a grasshopper in an agricultural landscape

Dispersal may be strongly influenced by landscape and habitat characteristics that could either enhance or restrict movements of organisms. Therefore, spatial heterogeneity in landscape structure could influence gene flow and the spatial structure of populations. In the past decades, agricultural intensification has led to the reduction in grassland surfaces, their fragmentation and intensification. As these changes are not homogeneously distributed in landscapes, they have resulted in spatial heterogeneity with generally less intensified hedged farmland areas remaining alongside streams and rivers. In this study, we assessed spatial pattern of abundance and population genetic structure of a flightless grasshopper species, Pezotettix giornae, based on the surveys of 363 grasslands in a 430‐km² agricultural landscape of western France. Data were analysed using geostatistics and landscape genetics based on microsatellites markers and computer simulations. Results suggested that small‐scale intense dispersal allows this species to survive in intensive agricultural landscapes. A complex spatial genetic structure related to landscape and habitat characteristics was also detected. Two P. giornae genetic clusters bisected by a linear hedged farmland were inferred from clustering analyses. This linear hedged farmland was characterized by high hedgerow and grassland density as well as higher grassland temporal stability that were suspected to slow down dispersal. Computer simulations demonstrated that a linear‐shaped landscape feature limiting dispersal could be detected as a barrier to gene flow and generate the observed genetic pattern. This study illustrates the relevance of using computer simulations to test hypotheses in landscape genetics studies.     

Elephant response to spatial heterogeneity in a savanna landscape of northern Tanzania

Landscape heterogeneity, namely the variation of a landscape property across space and time, can influence the distribution of a species and its abundance. Quantifying landscape heterogeneity is important for the management of semi‐natural areas through predicting species response to landscape changes, such as habitat fragmentation. In this paper, we tested whether the change in spatial heterogeneity of the vegetation cover due to farming expansion affected the distribution of the African elephant in the Tarangire‐Manyara ecosystem, northern Tanzania. Spatial heterogeneity (based on the normalized difference vegetation index) was characterized at multiple spatial scales using the wavelet transform and the intensity‐dominant scale method. Elephant distribution was estimated from time‐series aerial surveys using a kernel density function. The intensity, which relates to the contrast in vegetation cover, quantified the maximum variation in NDVI across multiple spatial scales, whereas the dominant scale, which represents the scale at which this maximum variation occurs, identified the dominant inter‐patches distance, i.e. the size of dominant landscape features. We related the dominant scale of spatial heterogeneity to the probability of elephant occurrence in order to identify: 1) the scale that maximizes elephant occurrence, and 2) its change between 1988 and 2001. Neither the dominant scale and intensity of spatial heterogeneity, nor the probability of the elephant occurrence changed significantly between 1988 and 2001. The spatial scale maximizing elephant occurrence remained constant at 7000 to 8000 m during each wet season. Compared to the findings of a recent, similar study in Zimbabwe, our results suggest that the change in the dominant scale was relatively small in Tarangire‐Manyara ecosystem and well within the critical threshold for elephant persistence. The method is a useful tool for monitoring ecosystems and their properties.     

2003-2018年土地利用变化对丹江口市景观格局与生态服务价值的影响

丹江口市是南水北调中线工程核心水源区,通过开展土地利用动态变化、景观格局变化与生态系统服务价值等研究,为丹江口库区生态安全提供科学支撑。以丹江口市2003-2018年4期遥感影像数据为基础,运用ENVI 5.3、ArcGIS 10.5以及Fragstats 4.2等软件,统计了丹江口市土地利用动态变化,分析了景观格局变化指数,计量了生态系统服务价值。结果表明：丹江口市土地利用类型变化显著,水域和林地面积、建设用地面积分别增加了38.07%、19.73%、11.63%,耕地和园地面积分别减少了42.83%、52.40%,除2003年土地利用程度高达25.02%,其余年份均保持在23%左右;景观空间格局变化明显,市域范围内各斑块类型趋于规则,呈均衡趋势分布,斑块类型间形成了良好的连接性,景观聚集程度逐渐提升,空间分布趋向集中;丹江口市生态系统服务价值不断增长,由2003年105.31×10⁸元增长至2018年116.99×10⁸元,其中水源涵养和土壤形成与保护生态价值最高,原材料生产、美学景观和食物生产占比较低。在未来城市建设中,应加大水域和林地的保护力度,优化调整土地利用结构,合理规划建设用地,发展无污染农业生产,适时增设自然景观,稳步提升区域生态系统服务价值。     

Determinants of distribution and abundance in the clouded apollo butterfly: a landscape ecological approach

Recent studies on the determinants of distribution and abundance of animals at landscape level have emphasized the usefulness of the metapopulation approach, in which patch area and habitat connectivity have often proved to explain satisfactorily existing patch occupancy patterns. A different approach is needed to study the common situation in which suitable habitat is difficult to determine or does not occur in well‐defined habitat patches. We applied a landscape ecological approach to study the determinants of distribution and abundance of the threatened clouded apollo Parnassius mnemosyne butterfly within an area of 6 km² of agricultural landscape in south‐western Finland. The relative role of 24 environmental variables potentially affecting the distribution and abundance of the butterfly was studied using a spatial grid system with 2408 grid squares of 0.25 ha, of which 349 were occupied by the clouded apollo. Both the probability of butterfly presence and abundance in a 0.25 ha square increased with the presence of the larval host plant Corydalis solida the cover of semi‐natural grassland, the amount of solar radiation and spalial autocorrelation in butterfly occurrence. Additionally, butterfly abundance increased with overall mean patch size and decreased with maximum slope angle and wind speed. Two advantages of the employment of a spatial grid system included the avoidance of a subjective definition of suitable habitat patches and an evaluation of the relative significance of different components of habitat quality at the same time with habitat availability and connectivity. The large variation in habitat quality was influenced by the abundance of the larval host plant and adult nectar sources but also by climatological. topographical and structural factors. The application of a spatial grid system as used here has potential for a wide use in studies on landscape‐level distribution and abundance patterns in species with complex habitat requirements and habitat availability patterns.     

基于贝叶斯网络的生态系统服务权衡协同关系及其驱动因子分析——以陕北黄土高原为例

了解生态系统服务的权衡协同关系及其驱动因子效应是实现生态系统有效管理和改善人类福祉的基础。以陕北黄土高原为例,定量评估其2018年土壤保持、产水服务、粮食供给和固碳服务,在构建贝叶斯网络生态系统服务模型的基础上,通过节点的重要性分析识别影响生态系统服务的关键节点,利用联合概率分布、概率推理和情景模拟探讨生态系统服务权衡协同关系及其驱动因子效应。结果表明：（1）陕北黄土高原各类生态系统服务空间异质性较强。其中,土壤保持、产水服务和固碳服务的空间分布情况较为一致,高值区集中在东南部,低值区在西北部,呈"南高北低"的分布特征;粮食供给呈"中部高、南北低"的分布特征。（2）土壤保持、产水服务和固碳服务之间互为协同关系,粮食供给分别与土壤保持、产水服务、固碳服务为权衡关系。其中,产水服务与固碳服务的协同关系、产水服务与粮食供给的权衡关系较强。（3）土地利用、降水和NPP （Net primary production）是影响生态系统服务权衡协同关系的主要驱动因子,其中土地利用主要影响生态系统服务的协同关系,而降水和NPP在影响协同关系的同时对权衡关系也有一定的制约作用。研究发现：不同驱动因子在不同状态下产生相同的协同（或权衡）方式,相同驱动因子在不同状态则会造成协同（或权衡）方式的差异。研究对于认识多种生态系统服务间的复杂关系及其驱动因子差异,为后续提出改善生态系统管理和提高人类福祉的对策与措施,具有重要的理论和实践价值。     

基于景观格局-服务的景观生态风险评价——以广州市为例

城市化对景观的结构和功能造成极大干扰,城市景观变化引起的生态风险受到城市生态建设的关注,但景观生态风险评价技术体系尚待深化,以促进风险防范决策。研究选取植被碳固定、土壤保持、水源涵养与提供和栖息地提供等景观服务改进景观脆弱度的评价方法,以广州市为案例研究区,评价了1990—2015年广州市城市景观生态风险及其时空变化特征。研究结果表明:(1)基于景观格局与服务的景观生态风险评价能够有效地评估城市景观生态风险的空间分布,但评价需要关注结果验证和辅助情景分析,方可为景观生态风险的预警和预测提供科学依据。(2)1990—2015年广州市的景观干扰度先增加后降低,2000年是景观干扰度变化的转折点;25年间,景观脆弱度不断增加,中脆弱度和高脆弱度比例之和维持在60%以上;2000年是景观生态风险的转折点,1990—2000年景观生态风险趋于增大,2000—2015年景观生态风险趋向降低;景观干扰度、脆弱度和生态风险在空间上呈现南部高于北部,西部高于东部的分布特征。(3)近25年,广州市景观生态风险与景观变化具有较好的空间一致性。维持低风险的比例为40.74%,基本都分布在北部山区,而维持高风险...     

Conservation biological control and enemy diversity on a landscape scale

Conservation biological control in agroecosystems requires a landscape management perspective, because most arthropod species experience their habitat at spatial scales beyond the plot level, and there is spillover of natural enemies across the crop–noncrop interface. The species pool in the surrounding landscape and the distance of crop from natural habitat are important for the conservation of enemy diversity and, in particular, the conservation of poorly-dispersing and specialized enemies. Hence, structurally complex landscapes with high habitat connectivity may enhance the probability of pest regulation. In contrast, generalist and highly vagile enemies may even profit from the high primary productivity of crops at a landscape scale and their abundance may partly compensate for losses in enemy diversity. Conservation biological control also needs a multitrophic perspective. For example, entomopathogenic fungi, plant pathogens and endophytes as well as below- and above-ground microorganisms are known to influence pest-enemy interactions in ways that vary across spatiotemporal scales. Enemy distribution in agricultural landscapes is determined by beta diversity among patches. The diversity needed for conservation biological control may occur where patch heterogeneity at larger spatial scales is high. However, enemy communities in managed systems are more similar across space and time than those in natural systems, emphasizing the importance of natural habitat for a spillover of diverse enemies. According to the insurance hypothesis, species richness can buffer against spatiotemporal disturbances, thereby insuring functioning in changing environments. Seemingly redundant enemy species may become important under global change. Complex landscapes characterized by highly connected crop–noncrop mosaics may be best for long-term conservation biological control and sustainable crop production, but experimental evidence for detailed recommendations to design the composition and configuration of agricultural landscapes that maintain a diversity of generalist and specialist natural enemies is still needed.