融入植被结构因子的生态单元制图法在城市生物多样性信息采集中的应用

以前所使用的生态单元制图模型中没有涉及植被时间和空间结构因子,然而一些研究结果显示植被的时空结构对于生物多样性有着重要的影响。因此,设计一个融入植被结构因子的改良城市生态单元制图模型,并且将其应用于瑞典赫尔辛堡市的绿色空间个案研究中,以期能够获得有关生物多样性方面的信息。这个改良的制图方法基于一个生态单元分类系统,此分类系统融入了4个植被结构因子,分别是:植被覆盖的连续性因子、优势乔木种的年龄因子、横向结构因子以及竖向结构因子。公共绿色空间信息的采集借助于全彩色航空照片的分析以及实地调查,生态单元图谱的绘制基于各个层级的生态单元分类重点。通过使用原生林地指示种或林地连续性指示种(AWIS)鉴定林地的连续性以及观测不同的植被结构下动物的分布情况得出,一些含有AWIS的生态单元是长连续性的林地,并且其含有较高的或潜在高的生物多样性;同时,植被的横向和竖向结构以及树木的年龄结构影响着鸟类和哺乳动物的分布、丰富度和多样性。得出融入植被时空结构的生态单元制图法是一个重要的调查城市生物多样性的方法,图谱能够显示出各个生态单元含有生物多样性价值的信息,基于此可以对今后的城市生物多样性保护和提高提出相应的策略。     

基于生态单元制图的宝鸡市城区生物多样性保护规划研究

为探寻适合我国城乡生物多样性保护的有效措施和方法,以宝鸡城区为研究对象,通过实地调研和室内制图相结合的研究方法,创建一套融入植被结构因子(植被水平结构因子、植被优势种的年龄因子、植被垂直结构因子、林木类型因子)的生态单元分类系统,将研究区域内的城市绿地现状以图谱形式表示。通过对不同植被结构的绿地中维管束植物物种丰富度的对比,以检验此分类系统在城乡生物多样性信息采集中的有效性。基于制图信息和检验结果,分析研究区域内绿地空间结构存在的问题并针对宝鸡市城乡生物多样性保护提出相应策略,以期为今后我国城乡生物多样性保护提供理论依据和实践方法。     

植被群落特征对城市生态系统服务的影响研究进展

生态空间（林地、灌木、草地、水体）所产生的生态系统服务极大的改善了人类的生存环境，在城市绿地破碎化日益严重、绿地质量逐渐降低、乡土植物逐渐减少、入侵风险逐渐加剧等生态背景下，如何维持稳定而持续增长的城市生态系统服务供给，一直困扰着当下从事城市生态学领域研究的学者和城市管理者。植被群落作为城市绿地系统的基本组成单元，在绿地破碎化趋势下，可作为研究内容来探讨城市生态系统服务维持或提升策略；植被群落泛指城市中常见的、具有明显边界的、按照一定分布规则的植物群落单元，既包括道路绿地、居住区绿地、公园绿地等，也包括城市郊野自然林地。但对植被群落生态功能的研究也多停留在对某一生态问题的简单相关性研究，缺乏系统性和整体性。从微观层面的植被群落角度，整合相关文献研究，介绍了受植被群落特征影响的6种典型城市生态系统服务，综述了植被群落特征对这6种城市生态系统服务的影响机理，对植被群落特征因子进行总结、归类，从树种特性、垂直结构、水平结构、其他4个角度构建了"植被群落特征因子对城市生态系统服务影响关系表"。最后面向典型生态系统服务提升提出了城市低质量植被群落地区的营建和更新原则，以期为今后城市园林部门、规划部门制定城市绿地系统规划提供基础性技术支撑。     

国家生态保护重要区域植被长势遥感监测评估

国家生态保护重要区域植被长势对于维持区域生态系统结构和功能的稳定性至关重要.以国家重点生态功能区、国家重要生态功能区、国家生物多样性保护优先区和国家级自然保护区等四类生态保护重要区域为研究区,选取年累积NDVI作为指示因子,监测评估了1998-2007年间国家生态保护重要区域的植被长势特征.结果表明:(1)国家生态保护重要区域总面积为536.59万km2,占全国陆地国土面积的55.89％.国家生物多样性保护优先区与国家重点生态功能区、国家重要生态功能区的重叠面积较大,分别占到相应生态功能区总面积的53.36％和50.20％.国家级自然保护区与其他三种类型区域的空间叠加关系较好,尤其与国家重点生态功能区,重叠面积占国家级自然保护区总面积的75.10％.国家重点生态功能区和国家重要生态功能区的重叠面积分别占各自面积的63.73％和39.15％.(2)对于植被长势总体状况,国家生态保护重要区域中东部的植被状况好于西部.植被状况较差的区域面积为10.59％,植被状况一般的区域面积为29.59％,植被状况好的区域面积为23.44％,植被状况较好的区域面积为36.39％.国家级自然保护区和生物多样性保护优优先区的植被状况好于国家重要生态功能区和国家重点生态功能区.国家级自然保护区的空间分布差异最大.(3)对于植被长势变化趋势,国家生态保护重要区域的植被状况整体呈现出变好趋势.62.39％区域面积的植被状况较为稳定,22.69％区域面积的植被状况呈现出变好趋势,14.93％区域面积的植被状况呈现出变差趋势.国家重要生态功能区的植被变好趋势最为明显,其次为国家生物多样性保护优先区.国家生物多样性保护优先区的植被变化趋势空间差异最大,国家级自然保护区的植被变化趋势空间差异最小.     

黄土丘陵区土地覆盖和生物多样性功能演化及预测

为探究黄土丘陵区土地覆盖和生物多样性功能演化,评价生物多样性保护视角下的最优生境,研究以宁夏彭阳县为研究区,1995、2000、2005、2010、2015年的Landsat TM影像为基础数据,集成3S技术获取土地覆盖时空动态变化特征,采用陷阱法于2012和2013年6—8月在研究区灌草混交林地、乔灌混交林地等6种不同生境内采集地表甲虫样本数据,利用InVEST-Habitate Quality模型评价生物多样性功能,结合采样数据探究最佳生境,借助CA-Marcov模型模拟研究区2020年土地覆盖及生物多样性功能。研究结果表明:(1)1995—2015年彭阳县土地覆盖及生物多样性功能发生显著变化,未利用地减少,城镇用地快速扩张,生境中天然封育草地和水平农田地变化明显,研究期间生物多样性功能经历了退化-优化的转变,2015年最佳;(2)模拟2020年土地覆盖中的水平农田地、城镇用地等较2015年有显著变化,生物多样性功能提高;(3)灌草混交林地是彭阳县生物多样性功能保护的最优生境,生境中固有的"88542"水平沟整地措施可作为当地典型生态恢复的最优模式;(4)InVEST模型和CA-Markov模型综合利用,普适性及准确性较好,研究区水平沟、鱼鳞坑、"88542"等水土保持工程和退耕还林还草、生态功能区划等生态恢复策略的实施和建设成效显著。     

生态敏感区旅游开发适宜性评价及生态制图方法

生态适宜性分析尽管在城市和区域生态规划中得到了广泛应用,然而在自然保护区、风景名胜区等涉及重要生态敏感区诸如旅游开发的空间布局和选址,以及规划和项目生态环境影响评价问题上,由于缺少系统的评价技术方法体系,却没有得到较好的推广。因此,提出了一种适用于山岳型生态敏感区旅游开发空间适宜性评价及生态制图的方法体系,并以内蒙古五当召风景旅游区为例,通过对地形地势、坡度坡向、土壤环境、植被覆盖、水文水系、地质岩性等因子及其反映出的水土流失、地质灾害、生物多样性和防洪排涝4种典型生态敏感要素的分析,开展了该方法的案例研究。最后,在以上单因子和综合因子的生态敏感性分析及空间适宜性制图基础上,通过与案例研究区各项旅游开发活动的空间布局进行叠合,针对性地提出了项目规划布局的调整建议和具体的生态保护措施。此外,该方法由于系统综合的考虑了影响山岳型生态敏感区开发建设活动中的各种生态敏感因子,并通过生态制图的方式在空间上得以显示,将有助于涉及生态敏感区项目的决策和管理部门更加有效地开展生态风险的防治并制定相应的监管措施,同时也为涉及该类型区域的生态环境影响评价提供科学有效的技术方法。     

生境因子对岩质边坡生态恢复过程中植被多样性的影响

通过对舟山市已生态恢复的岩质边坡进行植物群落调查,记录了36个不同生境条件下边坡样地中的植物种及生境因子,计算了4个植物物种多样性指数,利用广义线性混合模型分析了生境因子与边坡植被多样性交化的关系,以揭示生境因子对岩质边坡生态恢复植被的影响.结果表明:从1 a到7 a的岩质边坡生态恢复过程中,坡位对边坡植被多样性的影响最显著(P＜0.05),不同坡位的Shannon-Wiener指数、Margalef指数、物种丰富度差异明显,其变化呈现一致的趋势为下坡＞中坡＞上坡;坡向与Margalef指数显著相关(P＜0.05),从阳坡、半阳坡、半阴坡到阴坡,植被多样性呈总体上升趋势;随着边坡恢复年限的延长,边坡植被多样性逐渐增加,但没有表现出统计学意义上的差异(P＞0.05);坡度、海拔、土壤厚度对边坡植被多样性的变化无明显影响(P＞0.05);Pielou均匀度指数与各个生境因子均无显著关系,在边坡植被恢复过程中基本保持稳定的状态.因此,坡位、坡向是影响岩质边坡生态恢复过程中植被多样性最重要的因子;Margalef丰富度指数和Shannon-Wiener多样性指数是岩质边坡生态恢复过程中植物群落变化的主要指示因子.     

遥感用于森林生物多样性监测的进展

随着物种和栖息地的丧失,全球范围的生物多样性保护已经成为迫切的需要。航空航天技术的迅猛发展使遥感成为能提供跨越不同时空尺度监测陆地生态系统生物多样性的重要工具,这方面的研究在欧美等国已经有了小范围的开展,在国内刚刚起步。国外关于生物多样性遥感探测的方法基本有3种:1.利用遥感数据直接对物种或生境制图,进而估算生物多样性;2 .建立遥感数据的光谱反射率与地面观测物种多样性的关系模型;3.与野外调查数据结合直接在遥感数据上进行生物多样性指数制图。研究表明,物种直接制图法只能应用于较小的范围;生境制图的方法,应用广泛,技术相对成熟,研究范围局限于几百公里的范畴,但不能获取生境内部的多样性信息。光谱模型技术目前正处于探索阶段,对于植被复杂、生物多样性高的地域,具有较大的应用潜力。在遥感数据上直接进行生物多样性制图在加拿大已经得到了应用。     

地表蚂蚁在云南萨王纳地区植被恢复过程中的指示作用

为了查清地表蚂蚁在萨王纳地区人工植被恢复过程中的指示作用,采用陷阱法调查了云南省萨王纳地区人工林和自然植被地表蚂蚁多样性。(1)群落物种组成:采集蚂蚁40467头,隶属于5亚科19属47种。扁平虹臭蚁Iridomyrmes anceps是保护较好自然植被的常见种;而迈氏小家蚁Monomorium mayri是干扰较大的自然植被及多数人工林的常见种。(2)多度和α多样性:在人工林中,印楝林地表蚂蚁群落多度和α多样性最高,桉树林次之,新银合欢林最低。(3)群落相似性及β多样性:印楝林地表蚂蚁群落与自然植被灌草丛较接近,而其它人工林蚂蚁物种组成不相似;新银合欢林β多样性最高,βCs值在0.481—0.935;印楝林较低,βCs值在0.200—0.478。(4)相关性分析:地表蚂蚁群落物种丰富度S值及ACE值和草本植物群落S值及ACE值均正相关。印楝林和桉树林具有较高的α多样性,在当地生物多样性保护中具有积极意义;而新银合欢林是生境极度退化区域的重要植被恢复模式之一,这3种人工林对于萨王纳地区植被恢复具有重要作用。蚂蚁群落α多样性能够作为生物多样性的指示物,指示云南萨王纳地区植被恢复中生物多样性的状况。     

基于物种分布的北京平原生态网络构建

高强度的城市化活动导致了生物栖息地破碎化、退化和消失,是生物多样性减少的主要原因。建立城市地区生态网络是保护生物多样性的重要途径。因其他物种数据可获得性差,以观测的典型鸟类群落为指示物种,探讨构建生态网络,可为城市生物多样性保护提供新思路。以北京市平原区为研究范围,重点基于86种鸟类分布大数据,通过Maxent模型掩膜生成栖息地源地并进行分级,在GIS技术的支撑下,以土地利用数据建立鸟类活动阻力面,采用最小累积阻力模型算法,模拟并形成了平原地区分级的生物多样性保护网络。研究结果表明,河湖湿地和城市公园组成了北京平原地区生态网络的优势景观类型,占平原区生态空间的81%。基于景观类型大小与物种数量的线性关系筛选出分级生物栖息地,其中一级生物栖息地58个,二级生物栖息地146个,通过模型模拟形成了平原地区生物多样性保护的一二级生态网络,共948条网络,长3760km。筛选出重要生态节点12处,关键生态廊道6条,是保护平原地区生物多样性的重要生态设施。该生态网络的实施对于提升首都平原区的生物多样性具有重要价值,研究结果可为国土生态空间优化提供重要科学依据和参考。     

Richness of Lichen Species,Especially of Threatened Ones,Is Promoted by Management Methods Furthering Stand Continuity

Lichens are a key component of forest biodiversity. However, a comprehensive study analyzing lichen species richness in relation to several management types, extending over different regions and forest stages and including information on site conditions is missing for temperate European forests. In three German regions (Schwäbische Alb, Hainich-Dün, Schorfheide-Chorin), the so-called Biodiversity Exploratories, we studied lichen species richness in 631 forest plots of 400 m² comprising different management types (unmanaged, selection cutting, deciduous and coniferous age-class forests resulting from clear cutting or shelterwood logging), various stand ages, and site conditions, typical for large parts of temperate Europe. We analyzed how lichen species richness responds to management and habitat variables (standing biomass, cover of deadwood, cover of rocks). We found strong regional differences with highest lichen species richness in the Schwäbische Alb, probably driven by regional differences in former air pollution, and in precipitation and habitat variables. Overall, unmanaged forests harbored 22% more threatened lichen species than managed age-class forests. In general, total, corticolous, and threatened lichen species richness did not differ among management types of deciduous forests. However, in the Schwäbische-Alb region, deciduous forests had 61% more lichen species than coniferous forests and they had 279% more threatened and 76% more corticolous lichen species. Old deciduous age classes were richer in corticolous lichen species than young ones, while old coniferous age-classes were poorer than young ones. Overall, our findings highlight the importance of stand continuity for conservation. To increase total and threatened lichen species richness we suggest (1) conserving unmanaged forests, (2) promoting silvicultural methods assuring stand continuity, (3) conserving old trees in managed forests, (4) promoting stands of native deciduous tree species instead of coniferous plantations, and (5) increasing the amount of deadwood in forests.     

Change in Vegetation Patterns Over a Large Forested Landscape Based on Historical and Contemporary Aerial Photography

Changes to vegetation structure and composition in forests adapted to frequent fire have been well documented. However, little is known about changes to the spatial characteristics of vegetation in these forests. Specifically, patch sizes and detailed information linking vegetation type to specific locations and growing conditions on the landscape are lacking. We used historical and recent aerial imagery to characterize historical vegetation patterns and assess contemporary change from those patterns. We created an orthorectified mosaic of aerial photographs from 1941 covering approximately 100,000 ha in the northern Sierra Nevada. The historical imagery, along with contemporary aerial imagery from 2005, was segmented into homogenous vegetation patches and classified into four relative cover classes using random forests analysis. A generalized linear mixed model was used to compare topographic associations of dense forest cover on the historical and contemporary landscapes. The amount of dense forest cover increased from 30 to 43% from 1941 to 2005, replacing moderate forest cover as the most dominant class. Concurrent with the increase in extent, the area-weighted mean patch size of dense forest cover increased tenfold, indicating greater continuity of dense forest cover and more homogenous vegetation patterns across the contemporary landscape. Historically, dense forest cover was rare on southwesterly aspects, but in the contemporary forest, it was common across a broad range of aspects. Despite the challenges of processing historical air photographs, the unique information they provide on landscape vegetation patterns makes them a valuable source of reference information for forests impacted by past management practices.     

General and specific responses of understory vegetation to cervid herbivory across a range of boreal forests

Understanding the responses of ecological communities to perturbation is a key challenge within contemporary ecology research. In this study we seek to separate specific community responses from general community responses of plant communities to exclusion of large cervid herbivores. Cervid herbivory and forestry are the main drivers of vegetation structure and diversity in boreal forests. While many studies focus on the impact of cervids on trees, a high proportion of the biodiversity and ecosystem services in boreal forests is found in the field layer. However, experimental approaches investigating the influence of herbivory on understory vegetation are highly localised. In this study we use a regional‐scale design with 51 sites in four boreal forest regions of Norway, to investigate the influence of cervid herbivory on the physical and ecological structure of field layer vegetation. Our study sites cover a range of forest types differing in productivity, management and dominant cervid species, allowing us to identify generic responses and those that are specific to particular conditions. We found that the height of the field layer and the abundances of individual species were most susceptible to change following short‐term cervid exclusion across different forest types and cervid species. Total vegetation density and vascular plant diversity did not respond to cervid exclusion on the same time scale. We also found that the field‐layer vegetation in clear‐cut forests used by moose was more susceptible to change following cervid exclusion than mature forests used by red deer, but no strong evidence that the response of vegetation to herbivore exclusion varied with productivity. Our study suggests that the parameters that respond to cervid exclusion are consistent across forest types, but that the responsiveness of different forest types is idiosyncratic and hard to predict.     

Identifying practical indicators of biodiversity for stand-level management of plantation forests

Identification of valid indicators of biodiversity is a critical need for sustainable forest management. We developed compositional, structural and functional indicators of biodiversity for five taxonomic groups—bryophytes, vascular plants, spiders, hoverflies and birds—using data from 44 Sitka spruce (Picea sitchensis) and ash (Fraxinus excelsior) plantation forests in Ireland. The best structural biodiversity indicator was stand stage, defined using a multivariate classification of forest structure variables. However, biodiversity trends over the forest cycle and between tree species differ among the taxonomic groups studied. Canopy cover was the main structural indicator and affected other structural variables such as cover of lower vegetation layers. Other structural indicators included deadwood and distances to forest edge and to broadleaved woodland. Functional indicators included stand age, site environmental characteristics and management practices. Compositional indicators were limited to more easily identifiable plant and bird species. Our results suggest that the biodiversity of any one of the species groups we surveyed cannot act as a surrogate for all of the other species groups. However, certain subgroups, such as forest bryophytes and saproxylic hoverflies, may be able to act as surrogates for each other. The indicators we have identified should be used together to identify stands of potentially high biodiversity or to evaluate the biodiversity effects of silvicultural management practices. They are readily assessed by non-specialists, ecologically meaningful and applicable over a broad area with similar climate conditions and silvicultural systems. The approach we have used to develop biodiversity indicators, including stand structural types, is widely relevant and can enhance sustainable forest management of plantations.     

Effects of forest continuity on flying saproxylic beetle assemblages in small woodlots embedded in agricultural landscapes

Ancient forests are of considerable interest for strategies for biodiversity conservation. However, in European forest landscapes fragmented and harvested for a long time forest continuity might be no longer a key driver for flying organisms such as saproxylic beetles. In a study based on paired samples (n = 60 stands, p = 180 traps) of ancient and recent forests, we investigated the effects of forest continuity on saproxylic beetle assemblages in two French regions. Mean species richness was significantly related with deadwood volume in ancient forests, but not in recent forests. This loss of relationship between assemblages and their environment suggests that dispersal limitation is at work, at least for some species. Forest continuity had a significant effect on mean species richness and on the mean number of common species, but not on rare species. Forest continuity had a significant effect on assemblage composition in one out of the four cases tested. In both regions, we identified species associated with either recent or ancient forests. Finally, mean body size of species was significantly smaller in recent forests compared with ancient ones, as was their tree diameter preference, despite a higher volume of large deadwood in recent forests. These results lend support to using forest continuity as a criterion to identify sites of conservation importance, even in highly fragmented landscapes.     

Vertical and Horizontal Vegetation Structure across Natural and Modified Habitat Types at Mount Kilimanjaro

In most habitats, vegetation provides the main structure of the environment. This complexity can facilitate biodiversity and ecosystem services. Therefore, measures of vegetation structure can serve as indicators in ecosystem management. However, many structural measures are laborious and require expert knowledge. Here, we used consistent and convenient measures to assess vegetation structure over an exceptionally broad elevation gradient of 866–4550m above sea level at Mount Kilimanjaro, Tanzania. Additionally, we compared (human)-modified habitats, including maize fields, traditionally managed home gardens, grasslands, commercial coffee farms and logged and burned forests with natural habitats along this elevation gradient. We distinguished vertical and horizontal vegetation structure to account for habitat complexity and heterogeneity. Vertical vegetation structure (assessed as number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover) displayed a unimodal elevation pattern, peaking at intermediate elevations in montane forests, whereas horizontal structure (assessed as coefficient of variation of number, width and density of vegetation layers, maximum canopy height, leaf area index and vegetation cover) was lowest at intermediate altitudes. Overall, vertical structure was consistently lower in modified than in natural habitat types, whereas horizontal structure was inconsistently different in modified than in natural habitat types, depending on the specific structural measure and habitat type. Our study shows how vertical and horizontal vegetation structure can be assessed efficiently in various habitat types in tropical mountain regions, and we suggest to apply this as a tool for informing future biodiversity and ecosystem service studies.     

Analysis of macrofungal communities reveals a complex reciprocal influence between Mediterranean montane calcareous grassland and surrounding forest habitats

Fungi are essential components of all terrestrial ecosystems. Despite the crucial ecological role of soil fungi in grasslands, knowledge about fungal community diversity and structure in Mediterranean meadow habitats is still fragmentary. We analyzed macrofungal communities in three geographically distinct Mediterranean montane calcareous grasslands and surrounding forests, by means of fruit body surveys. We investigated a number of biotic and abiotic factors influencing the studied fungal communities, including plant species composition. Out of 6365 fruit bodies, a total of 268 species belonging to 84 genera were found. In general, there was a significant correlation between plant species richness and fungal richness. Variation in vegetation and plant community structure accounted for approximately 20% of variance in fungal community structure. Tree and shrub vegetation played a dominant role in shaping the analyzed fungal communities, both in meadows and surrounding forests, with particular influence on ectomycorrhizal, litter, and lignicolous saprotrophic fungi. Fungal biodiversity in the studied meadows was increased by the presence of tree and shrub species from the adjacent forests, but was reduced by the increasing vegetation cover.     

Separating forest continuity from tree age effects on plant diversity in the ground and epiphyte vegetation of a Central European mountain spruce forest

Forest continuity has been identified as an important factor influencing the structure and diversity of forest vegetation. Primary forests with centuries of continuity are usually more diverse than young secondary forests as forest are colonized only slowly and because the former are richer in old tree individuals. In the present study, performed in unmanaged high-elevation spruce forests of the Harz Mountains, Germany, we had the unique opportunity to separate the effects of forest continuity and tree age on plant diversity. We compared an old-growth spruce forest with century-long habitat continuity with an adjacent secondary spruce forest, which had naturally established on a former bog after 1796 when peat exploitation halted. Comparative analysis of the ground and epiphyte vegetation showed that the plant diversity of the old-growth forest was not higher than that of the secondary forest with a similar tree age of >200 years. Our results suggest that a period of >200 years was sufficient for the secondary forest to be colonized by the whole regional species pool of herbaceous and cryptogam forest plants and epiphytes. Therefore, it is likely that habitat structure, including the presence of old and decaying trees, was more important for determining plant diversity than the independent effect of forest continuity. Our results are probably not transferrable to spruce forests younger than 200 years and highly fragmented woodlands with long distances between new stands and old-growth forests that serve as diaspore sources. In addition, our results might be not transferable to remote areas without notable air pollution, as the epiphyte vegetation of the study area was influenced by SO₂ pollution in the second half of the 20th century.