基于恢复生态学的泰山地区“山水林田湖草”生态修复研究

目前大多地方生态修复工作往往是对各类生态系统分割式治理,不利于生态系统的整体修复。“山水林田湖草是生命共同体”理念要求各生态要素和生态系统之间的协同特征和有机联系,恢复生态学理论则关注受损生态系统的驱动因素、生态恢复的路径和干预措施,两者的结合能够为生态保护和修复提供坚实的理论和技术基础。基于恢复生态学理论,以泰山地区为研究对象,运用物能循环和转化的生态学原则对受损生态系统生态关键问题进行诊断,明确了“山水林田湖草”生命共同体中的各要素（子系统）在生态过程中的相互影响及相互制约关系,厘清了泰山地区矿山开采（地质受损）-植被破坏-水土流失-景观失调的生态受损与退化机制,在此基础上提出了“地貌重塑、植被重建、水体重构、景观重现”的生态恢复思路。并尝试构建包含生态风险、生态状况和生态恢复能力三重准则共13项指标的评价体系,以期通过生态恢复效果的评价与监测引导生态恢复目标的有效实现。     

道路网络对景观生态风险的影响——以云南省红河流域为例

道路网络扩展既影响周围的景观格局,也对生态过程造成直接或间接的影响。以云南省红河流域为研究区域,利用GIS和RS技术,进行格网划分,从空间上分析道路对景观格局和土壤侵蚀的影响,并通过基于景观格局和过程的景观生态风险指数计算,分析道路网络扩展影响下的景观生态风险规律。结果表明:红河流域道路周围景观类型以耕地、林地和草地为主,其中林地和草地的格局风险指数随着距离道路的增加而减少,受道路影响显著;一级路、三级路和四级路缓冲区内土壤侵蚀量随着距离道路的增加而减少,三四级路分布广泛,更容易发生土壤侵蚀;道路密度和基于景观格局和过程的景观生态风险指数在空间分布上具有一定的相关性。     

国内外主要湾区生态系统特征、修复理论与技术模式

通过总结粤港澳大湾区、东京湾区和旧金山湾区等国内外主要湾区的生态系统特征、生态修复理论和实践研究进展,在辨析生态修复概念内涵的基础上,基于Meta-Analysis及综合分析方法,分析了生态系统退化机制及驱动因子,归纳总结湾区生态修复的主要理论基础、技术模式及案例。结果表明：（1）国内外三大主要湾区的生态系统特征为森林占比最高,其次是农田和草地占比,城镇占比第三。森林一般分布在湾区外围,城镇分布在湾区内核河口三角洲附近。（2）湾区生态修复理论包括以恢复生态学、景观生态学和复合生态系统生态学为基础的三种修复理论,生态修复的类别分为补救修复、改善修复、生态恢复和复垦等。（3）湾区生态修复技术模式包括主动修复、被动修复和重建等三类技术模式。在总结梳理生态修复理论和技术模式的基础上,结合当前国内生态修复存在问题,本文提出我国和广东省开展生态修复实践的建议和展望,以期为粤港澳大湾区生态修复提供一定的理论指导。     

黄土区被草土质路面产流产沙过程及防蚀效果

通过变坡钢槽装土和人工降雨的室内模拟试验,分析了黄土区裸露土质路和被草土质路(被草土质路种植早熟禾)路面的产流产沙过程及被草土质路的防蚀效果.结果表明:在相同雨强和坡度条件下,研究区被草土质路的径流系数大于裸露土质路;两种路面的径流系数均随着雨强和坡度的增加而增大;不同雨强、相同坡度条件下,径流系数与降雨历时呈对数关系,径流系数与雨强、坡度呈二次函数关系;两种路面的土壤侵蚀速率均随着雨强和坡度的增加而增大;相同降雨条件下,被草土质路的土壤侵蚀速率低于裸露土质路;在不同雨强条件下,被草土质路的平均减沙效益达47.22%;在不同坡度条件下,被草土质路的平均减沙效益达26.24%;被草土质路通过增加路面糙度和增大路面阻力可降低水流搬运泥沙的能力,起到了减少路面产沙量的作用.     

山水林田湖草生态问题系统诊断与保护修复综合分区研究——以陕西省为例

山水林田湖草生态保护修复分区的划定,是科学合理的分区域提出生态保护修复方案的基础。但是,目前生态保护修复分区的划定,对于生态系统问题诊断的综合性考虑不足,未能很好的体现山水林田湖草生命共同体的理念。因此,选取了8个指标综合考察了陕西省的山水林田湖草生态系统问题,并以小流域为基本单元,划定了陕西省山水林田湖草生态保护修复综合分区。研究表明：（1）2015年陕西省生态修复指数平均值为0.39（该值越小表明山水林田湖草人的综合问题越严重）,各流域生态修复指数在0.23-0.60之间。总体来看,陕西省生态修复指数的空间分异较为明显,呈现自南向北逐渐递减的格局。（2）划分了8个生态保护修复分区,包括陕南秦岭东部地区、关中平原中部的城镇地区、汉江河谷盆地、陕北黄土高原中南部地区、陕南秦岭山区、陕北黄土高原北部地区、关中平原地区和陕南大巴山地区。在生态系统问题综合诊断方面,水土流失、植被退化、降水资源不足是陕北黄土高原地区主要生态问题;南部秦巴山区的生态系统则易受到极端降水和土壤侵蚀的影响;关中平原主要存在林草植被退化、矿产资源开采强度大和水土流失等生态问题。     

城市生态用地的空间结构及其生态系统服务动态演变——以常州市为例

生态用地是城市社会-经济-自然复合生态系统重要的组成部分,为城市提供多种显著的生态系统服务。应用遥感、地理信息系统技术和生态系统服务评估等方法,针对城市生态用地的空间结构与服务功能演变科学问题,通过对常州市区1991、1996、2001和2006年4个时段遥感图像的处理与比较分析,揭示了常州市区15a来城市空间景观格局的演变规律,评估了由城市生态用地改变所导致的生态系统服务的变化。研究结果表明,1991-2006年间,常州市区生态用地占市区面积的比例由89.2%降低至65.1%。1991-2001年,林地、农田和水体的面积都呈不同程度的下降趋势。2001-2006年,林地面积增加基本回到1996年水平。常州市区生态用地主要为城市提供了农林产品生产、气候调节、涵养水源、水土保持、生物多样性保护等生态系统服务。在过去15a间,由于城市化占用生态用地,常州市区生态用地生态系统服务的经济价值总体降低了19.3%。其中,农田的生态服务价值减少最大,减少了32.3%。研究结果表明,常州城市空间景观格局演变与生态系统服务变化之间存在着密切相关性,研究可为城市生态系统服务强化、城乡土地利用规划与管理、城市可持续发展等提供科学方法与决策参考。     

三峡库区土质道路侵蚀产沙过程的模拟降雨试验

以三峡库区王家桥小流域为研究区,通过野外调查选择了5个典型路段,在1.0 mm min~(-1)模拟降雨条件下研究了土质道路降雨-径流-泥沙关系.结果表明,土质道路被高度压实,但使用强度和管护方式差异致使容重、路面浮土、杂草盖度、饱和导水率等差异显著.土质道路仅需1～3 mm降雨就能产生地表径流,7～10 mm的降雨使径流趋于稳定,径流系数超过60%,特别是车流量较大干道的径流系数超过70%,平均和峰值径流量达0.69 mm min~(-1)和0.84 mm min~(-1).土质路面大量浮土致使初始径流含沙量高,然后快速下降并趋于稳定.由于路面浮土量大和在降雨过程中能形成人工细沟的车辙等导致较大车流量干道的土壤流失率是其它路段3～4倍.土质道路的容重和路面浮土与径流系数和土壤流失量呈显著正相关,饱和导水率则呈显著负相关;路面杂草能显著减少径流,防治路面侵蚀.     

典型红壤区自然生态修复的适用性

自然修复主要通过封山育林、禁止农作、禁牧禁伐措施,减少人类对环境的扰动,利用自然生态环境的自我演替能力,恢复生态环境,实现生态平衡。自然修复作为一种成本低、无污染的生态修复手段很早就受到人们重视,但关于自然修复适用范围的研究较少。为了正确认识自然修复的适用性,选择了我国南方红壤地区长期遭受严重土壤侵蚀危害的福建省长汀县为研究对象,通过对长期自然修复样地的监测资料分析,发现在坡度条件为20%—30%下,当植被覆盖度低于20%的退化阈值时,严重的土壤侵蚀引发的土壤肥力损失将导致生态系统自我退化,自然修复不仅无法改善当地的生态系统,反而会引起生态系统的进一步恶化。由此可见,自然修复并不适合所有的生态系统,当生态系统退化到一定程度时,退化生态系统必须通过人工干预来修复。因此,必须探索适合当地的生态修复模式,在生态系统退化突破阈值时,红壤丘陵区应通过恢复土壤肥力、促进自然植被覆盖度增加、综合提高生态系统健康水平。     

基于时空分析的生态保护与修复试点工程实施效果评估——以赣州市为例

以“山水林田湖草生命共同体”为中心思想,从生态系统的格局和质量两个方面,对赣州市山水林田湖生态保护与修复试点工程实施效果进行了综合评估。结果如下：（1）从生态系统格局来看,2015到2018年,赣州市森林、农田和城镇生态系统面积明显增加,超过40%的草地生态系统转变为森林生态系统,且近45%的城镇生态系统面积增量由草地生态系统贡献。此外,多数自然生态系统的斑块破碎化加剧,森林生态系统破碎化现象最为明显,最大斑块指数从54.36降低到37.41,而半自然生态系统最大斑块指数增大。（2）从生态系统质量来看,赣州市归一化植被指数稳定在0.7以上并呈增长趋势,水土流失综合治理面积从16543.8 km²增长到18550.4 km²,重点流域水质基本稳定在Ⅱ、Ⅲ级,城镇生态系统受土壤重金属污染的风险较小,但部分县区农田生态系统受一种或多种土壤重金属污染的风险较大。整体而言,赣州市山水林田湖生态保护与修复试点工程取得了显著成效,较好的完成了实施方案中的规划目标。在进一步的生态保护与修复工作中,应重视赣州市自然生态系统斑块破碎化严重地区、水质出现波动较大的河流断面以及农田生态系统受土壤重金属污染威胁较大的县区。     

道路网络扩展对区域生态系统的影响——以景洪市纵向岭谷区为例

道路网络的存在和扩展影响着周边景观的生态格局和过程,进而影响区域生态安全,定量表达道路影响域生态系统变化对生态系统管理具有重要意义.选取景洪市为研究区,利用缓冲区分析、对比分析和情景分析,研究道路与生态系统格局变化的关系,进而揭示不同道路类型对区域生态安全的影响.结果表明：近20a研究区林地、灌丛有所减少,旱地和建设用地增加显著,而道路为显著的驱动因子.景观的多样性,均匀度,斑块密度和人工干扰指数也随着道路缓冲距离增加而降低.道路影响域内林地受道路影响最大,其次为草地,旱地或灌丛,而旱地的斑块数目受低等级道路影响最多,其他等级林地数目最多.情景分析表明,随着道路网络的扩展,生态系统分维数、斑块数目增加,平均斑块面积减少,显示破碎化程度加剧,而低等级道路对区域景观格局的变化贡献率最大.     

Effects of Road Decommissioning on Carbon Stocks,Losses, and Emissions in North Coastal California

During the last 3 decades, many road removal projects have been implemented on public and private lands in the United States to reduce erosion and other impacts from abandoned or unmaintained forest roads. Although effective in decreasing sediment production from roads, such activities have a carbon (C) cost as well as representing a carbon savings for an ecosystem. We assessed the carbon budget implications of 30 years of road decommissioning in Redwood National Park in north coastal California. Road restoration techniques, which evolved during the program, were associated with various carbon costs and savings. Treatment of 425 km of logging roads from 1979 to 2009 saved 72,000 megagrams (Mg) C through on‐site soil erosion prevention, revegetation, and soil development on formerly compacted roads. Carbon sequestration will increase in time as forests and soils develop more fully on the restored sites. The carbon cost for this road decommissioning work, based on heavy equipment and vehicle fuel emissions, short‐term soil loss, and clearing of vegetation, was 23,000 Mg C, resulting in a net carbon savings of 49,000 Mg C to date. Nevertheless, the degree to which soil loss is a carbon sink or source in steep mountainous watersheds needs to be further examined. The ratio of carbon costs to savings will differ by ecosystem and road removal methodology, but the procedure outlined here to assess carbon budgets on restoration sites should be transferable to other systems.     

Impacts of logging roads on tropical forests

Road networks are expanding in tropical countries, increasing human access to remote forests that act as refuges for biodiversity and provide globally important ecosystem services. Logging is one of the main drivers of road construction in tropical forests. We evaluated forest fragmentation and impacts of logging roads on forest resilience and wildlife, considering the full life cycle of logging roads. Through an extensive evidence review we found that for logging road construction, corridors between 3 and 66 m (median 20 m) width are cleared, leading to a loss of 0.6–8.0 percent (median 1.7%) of forest cover. More severe impacts are increased fire incidence, soil erosion, landslides, and sediment accumulation in streams. Once opened, logging roads potentially allow continued access to the forest interior, which can lead to biological invasions, increased hunting pressure, and proliferation of swidden agriculture. Some roads, initially built for logging, become converted to permanent, public roads with subsequent in‐migration and conversion of forest to agriculture. Most logging roads, however, are abandoned to vegetation recovery. Given the far‐reaching impacts of the roads that become conduits for human access, its control after the end of logging operations is crucial. Strategic landscape planning should design road networks that concentrate efficient forest exploitation and conserve roadless areas.     

Do well-connected landscapes promote road-related mortality?

Cost surface (CS) models have emerged as a useful tool to examine the interactions between landscapes patterns and wildlife at large-scale extents. This approach is particularly relevant to guide conservation planning for species that show vulnerability to road networks in human-dominated landscapes. In this study, we measured the functional connectivity of the landscape in southern Portugal and examined how it may be related to stone marten road mortality risk. We addressed three questions: (1) How different levels of landscape connectivity influence stone marten occurrence in montado patches? (2) Is there any relation between montado patches connectivity and stone marten road mortality risk? (3) If so, which road-related features might be responsible for the species’ high road mortality? We developed a series of connectivity models using CS scenarios with different resistance values given to each vegetation cover type to reflect different resistance to species movement. Our models showed that the likelihood of occurrence of stone marten decreased with distance to source areas, meaning continuous montado. Open areas and riparian areas within open area matrices entailed increased costs. We found higher stone marten mortality on roads in well-connected areas. Road sinuosity was an important factor influencing the mortality in those areas. This result challenges the way that connectivity and its relation to mortality has been generally regarded. Clearly, landscape connectivity and road-related mortality are not independent.     

Herbs and herbal constituents active against snake bite

Snake bite, a major socio-medical problem of south east asian countries is still depending on the usage of antisera as the one and only source of treatment, which has its own limitations. In India, mostly in rural areas, health centres are inadequate and the snake bite victims mostly depend on traditional healers and herbal antidotes, as an alternative treatment. The present review has been focussed on the varied folk and traditional herbs and their antisnake venom compounds, which might be a stepping stone in establishing the future therapy against snake bite treatment and management.     

Stone marten (Martes foina) habitat in a Mediterranean ecosystem: effects of scale, sex, and interspecific interactions

Mediterranean ecosystems are inherently patchy, challenging habitat-use behavior. Certain mammalian carnivores take advantage of this patchiness by a strategy of habitat complementation/supplementation, which is invariant to the scale of analysis. To test if the same behavior is adopted by the stone marten, we used a combined data set of capture and radio-tracking data at three scales of analysis (1-m, 25-m, and 452-m radius plots). We used compositional analysis to test if there were sex-specific differences in foraging and resting habitat use of stone martens and if these patterns were affected by the presence of other mesocarnivores. Our results showed that stone martens are found both in rural and forested landscapes. Foraging and resting activities occurred far from roads in large and complex patches of cork oak woodlands, riparian vegetation, orchards, and pastureland. Use varied with the scale of analysis and the sex. At smaller scales, females use pastures for foraging and orchards for resting, whereas riparian vegetation and sparse cork oak forests influenced this use at larger scales. Males, on the other hand, were more consistent across scales, using riparian areas and dense cork oak woodlands for foraging and pastures for resting. Stone martens shared the same areas with other coexisting mesocarnivores. Stone martens use cork oak woodlands and complement/supplement this use with other land cover types. The consistent use of cork oak woodlands across scales emphasizes the importance of this land cover to the preservation of functional Mediterranean ecosystems in southern Portugal.     

Population Migration: Implications for Lymphatic Filariasis Elimination Programmes

Human population migration is a common phenomenon in developing countries. Four categories of migration—endemic to nonendemic areas, rural to urban areas, non-MDA areas to areas that achieved lymphatic filariasis (LF) control/elimination, and across borders—are relevant to LF elimination efforts. In many situations, migrants from endemic areas may not be able to establish active transmission foci and cause infection in local people in known nonendemic areas or countries. Urban areas are at risk of a steady inflow of LF-infected people from rural areas, necessitating prolonged intervention measures or leading to a prolonged “residual microfilaraemia phase.” Migration-facilitated reestablishment of transmission in areas that achieved significant control or elimination of LF appears to be difficult, but such risk can not be excluded, particularly in areas with efficient vector-parasite combination. Transborder migration poses significant problems in some countries. Listing of destinations, in endemic and nonendemic regions/countries, and formulation of guidelines for monitoring the settlements and the infection status of migrants can strengthen the LF elimination efforts.     

Road effects on vegetation composition in a saline environment

Aims Road effects from maintenance and traffic have the potential to alter plant communities, but the exact relationships between these effects and changes in plant community composition have not often been studied in diverse environments. To determine the direction and level of community composition changes in saline environment due to road effects, we conducted a study along roads of different ages and in nearby non-road (i.e. natural) areas in the Yellow River Delta, China. Additionally, to potentially elucidate the mechanisms underlying the changes in the richness and composition of plant communities along roads, we evaluated physiochemical changes in soil of roadside and non-road areas.Methods Floristic and environmental data were collected along roadside of different ages and nearby non-road areas. To evaluate plant communities at each site, six 2 m × 2 m quadrats were placed at 3-m intervals along roads and six quadrats were arranged randomly in non-road areas. To determine the difference in plant community composition between roadside and non-road areas, we measured species richness and the abundance of each species, examined species turnover and floristic dissimilarity between the two areas and positioned plant species and sites in an abstract multivariate space. Plant community (species richness, percentage of halophytes) and soil physicochemical properties (pH, salinity, moisture content, bulk density, nitrate and ammonium nitrogen concentration) were compared between roadside and non-road areas (young roadside vs. corresponding non-road areas, old roadside vs. corresponding non-road areas) by using t -tests. Classification and ordination techniques were used to examine the relationship between vegetation and related environmental variables in both roadside and non-road areas.Important findings For both the young and old roadside areas, species richness in roadside areas was significantly higher than in non-road areas and high floristic dissimilarity values indicated that roadside and non-road areas differed greatly in community composition. In both the young and old roadside areas, the plant communities in roadside areas had lower percentages of halophytes than non-road communities. Correspondence analysis and two-way indicator species analysis showed that halophytes dominated in the non-road areas, while a number of typical non-salt-tolerant species dominated in the roadside areas. Compared to non-road areas, activities associated with roads significantly decreased soil moisture, bulk density and salinity and increased soil pH and nitrate content. Forward selection for the environmental variables in canonical correspondence analysis showed that soil salinity was the most important factor related to the variation of species composition between roadside and non-road areas. Our study demonstrates that road effects have a significant impact on the associated vegetation and soil, and these changes are consistent across roads of different ages in our system.     

Road exposure and the detectability of birds in field surveys

Road ecology, the study of the impacts of roads and their traffic on wildlife, including birds, is a rapidly growing field, with research showing effects on local avian population densities up to several kilometres from a road. However, in most studies, the effects of roads on the detectability of birds by surveyors are not accounted for. This could be a significant source of error in estimates of the impacts of roads on birds and could also affect other studies of bird populations. Using road density, traffic volume and bird count data from across Great Britain, we assess the relationships between roads and detectability of a range of bird species. Of 51 species analysed, the detectability of 36 was significantly associated with road exposure, in most cases inversely. Across the range of road exposure recorded for each species, the mean positive change in detectability was 52% and the mean negative change was 36%, with the strongest negative associations found in smaller-bodied species and those for which aural cues are more important in detection. These associations between road exposure and detectability could be caused by a reduction in surveyors’ abilities to hear birds or by changes in birds’ behaviour, making them harder or easier to detect. We suggest that future studies of the impacts of roads on populations of birds or other taxa, and other studies using survey data from road-exposed areas, should account for the potential impacts of roads on detectability.