Spatial and temporal variability of the phenological seasons in Germany from 1951 to 1996

Various indications for shifts in plant and animal phenology resulting from climate change have been observed in Europe. This analysis of phenological seasons in Germany of more than four decades (1951–96) has several major advantages: (i) a wide and dense geographical coverage of data from the phenological network of the German Weather Service, (ii) the 16 phenophases analysed cover the whole annual cycle and, moreover, give a direct estimate of the length of the growing season for four deciduous tree species. After intensive data quality checks, two different methods – linear trend analyses and comparison of averages of subintervals – were applied in order to determine shifts in phenological seasons in the last 46 years. Results from both methods were similar and reveal a strong seasonal variation. There are clear advances in the key indicators of earliest and early spring (?0.18 to ?0.23 d y^?1) and notable advances in the succeeding spring phenophases such as leaf unfolding of deciduous trees (?0.16 to ?0.08 d y^?1). However, phenological changes are less strong during autumn (delayed by + 0.03 to + 0.10 d y^?1 on average). In general, the growing season has been lengthened by up to ?0.2 d y^?1 (mean linear trends) and the mean 1974–96 growing season was up to 5 days longer than in the 1951–73 period. The spatial variability of trends was analysed by statistical means and shown in maps, but these did not reveal any substantial regional differences. Although there is a high spatial variability, trends of phenological phases at single locations are mirrored by subsequent phases, but they are not necessarily identical. Results for changes in the biosphere with such a high resolution with respect to time and space can rarely be obtained by other methods such as analyses of satellite data.     

淮河流域暖季极端高温干旱复合事件的演变特征及其与气候和植被的关系

使用淮河流域1981年至2020年的149个气象站点的气温和相对湿度数据,分析了流域暖季极端高温干旱复合事件(Compound Drought and Heat Events,CDHEs)的时空演变特征,并通过趋势分析和相关分析法探讨了CDHEs与气候和植被的关系。结果表明:①CDHEs的发生日数在年代际尺度上呈现明显的增加趋势,并且范围扩大,频发区逐渐向淮河流域中西部移动;②在年际尺度上,CDHEs随时间序列呈显著的波动上升趋势,空间分布上以西北部为中心向四周递减。连续CDHEs事件呈年际变化,最大2至4天的连续事件存在波动,2019年达到高峰,并且在流域内零散或成片出现;③在月际尺度上,CDHEs的发生日数在6月最多,其次是5月、7月、9月和8月。淮河流域入汛前的旱情和入汛后的旱涝急转都容易导致CDHEs发生,而且随着月际变化向南移动;④CDHEs对水热条件和大气环流具有特别的敏感性。在850hPa反气旋和500hPa显著高压异常的控制下,高温、低湿、高蒸发和降水少的气候背景有利于淮河地区CDHEs的形成,尤其是在淮河中西部地区。因此,CDHEs的发生与气候变化密切相关;⑤CDHEs与植被生长也存在显著关系。CDHEs与GPP呈显著的负相关,而与NDVI呈显著的正相关,显著地区的土地类型以耕地和城乡、工矿、居民用地为主。GPP和NDVI的不同步可能是因为多种因素的非线性相互作用,而不仅仅是单一因素的影响。此外,对于GPP和NDVI来说,土壤含水量至关重要。总之,本文对淮河流域CDHEs的时空分布特征进行了深入研究,并探讨了其与气候和植被的关系。研究结果可以为该地区的气象灾害防御和生态环境保护提供科学依据和参考。     

Application of a Gondwanan perspective to restore ecological integrity in the south‐western Australian global biodiversity hotspot

Bounded by ocean and desert, the isolated, predominately Mediterranean‐climate region of south‐western Australia (SWA) includes nine bioregions (circa 44 million hectares). The ecological integrity of the landscapes in this global biodiversity hotspot has been compromised by deforestation, fragmentation, exploitation, and introduced biota. Nature and degree of transformation varies between four interconnected landscapes (Swan Coastal Plain; South‐west Forests; Wandoo Woodlands; and Great Western Woodlands). A Gondwanan perspective emphasizes a venerable biota and a cultural component to deep time. The particular importance of remnants and protected areas is recognized in restoring ecological integrity to Gondwanan landscapes. The nature and magnitude of the restoration task in these ancient, and neighboring, landscapes require higher levels of investment and more time than do recent landscapes. The protection, conservation, restoration, and rehabilitation of ecological integrity require multiple approaches in each landscape as well as consideration of the whole. Active conservation of biota and minimizing the impact of industrial‐ and agricultural‐use are priorities. Integrating a climate focus and rethinking fire are critical restoration considerations to future trajectories under anthropogenic climate change. A legislative mandate to coordinate industrial‐scale restoration and active conservation to build from protected areas must become a societal priority to restore ecological integrity.     

The relationship of the phase and amplitude of the annual cycle of CO2 to phenological events

Background: A key current issue in studies of global CO₂ is the cause of the recent pronounced changes in the timing (phase) and amplitude of its annual cycle.

Aim: To use a sensitivity analysis in order to identify the most influential parameters in a new four-box diffusion model of global CO₂ transport.

Methods: A new diffusion model of global atmospheric transport is developed, implemented by optimisation and used to assess the effects of oceanic, terrestrial and anthropogenic CO₂ fluxes on the annual CO₂ cycle. As the terrestrial phenology of living organisms in the temperate zones is identified as the central process of concern an improved phenological model for the temperate zones is proposed and used in up-scaling from plant to planet.

Results: The diffusion model is found to be able to mimic many of the features observed by the GLOBALVIEW-CO₂ network, including the global trend, latitudinal gradient, and annual waveform.

Conclusions: It is concluded that, out of five rival hypotheses considered at the outset, the springtime phenology of terrestrial biomes is the dominant controller of recent changes to the annual CO₂ cycle.     

1982—2009年基于卫星数据的北半球中高纬地区植被春季物候动态及其与气候的关系

深入认识北半球植被物候在全球变暖背景下的动态变化特征,对于评估和预测生态系统结构和功能对气候变化的响应有重要的指示作用.遥感技术是获取北半球植被春季物候的最重要方法,但是由于物候提取算法的差异,目前还存在较大的不确定性.本文利用5种方法,基于卫星获取的归一化植被指数估算了北半球中高纬地区1982—2009年植被春季物候开始日期,分析了该日期的多年动态变化的时空特征,并探讨了气候变化对春季物候变化的影响.结果表明: 研究区植被春季物候开始日期呈现提前趋势,研究期间提前(4.0±0.8) d,其中,欧亚大陆提前速率为(0.22±0.04) d·a^-1,显著高于北美大陆的变化速率(0.03±0.02 d·a^-1);不同植被类型的变化趋势不同,5种方法都显示草地表现为显著提前趋势,而林地的提前趋势不显著.区域平均的植被春季物候开始日期的年际波动主要受春季温度的变化所驱动(r² =0.61,P<0.001), 温度每上升1 ℃,可以导致春季物候提前(3.2±0.5) d,而春季降水影响不显著(P>0.05).     

Genetic structure and conservation of Mountain Lions in the South-Brazilian Atlantic Rain Forest

The Brazilian Atlantic Rain Forest, one of the most endangered ecosystems worldwide, is also among the most important hotspots as regards biodiversity. Through intensive logging, the initial area has been reduced to around 12% of its original size. In this study we investigated the genetic variability and structure of the mountain lion, Puma concolor. Using 18 microsatellite loci we analyzed evidence of allele dropout, null alleles and stuttering, calculated the number of allele/locus, PIC, observed and expected heterozygosity, linkage disequilibrium, Hardy-Weinberg equilibrium, F(IS), effective population size and genetic structure (MICROCHECKER, CERVUS, GENEPOP, FSTAT, ARLEQUIN, ONESAMP, LDNe, PCAGEN, GENECLASS software), we also determine whether there was evidence of a bottleneck (HYBRIDLAB, BOTTLENECK software) that might influence the future viability of the population in south Brazil. 106 alleles were identified, with the number of alleles/locus ranging from 2 to 11. Mean observed heterozygosity, mean number of alleles and polymorphism information content were 0.609, 5.89, and 0.6255, respectively. This population presented evidence of a recent bottleneck and loss of genetic variation. Persistent regional poaching constitutes an increasing in the extinction risk.     

Balancing economic costs and ecological outcomes of passive and active restoration in agricultural landscapes: the case of Brazil

Forest restoration requires strategies such as passive restoration to balance financial investments and ecological outcomes. However, the ecological outcomes of passive restoration are traditionally regarded as uncertain. We evaluated technical and legal strategies for balancing economic costs and ecological outcomes of passive versus active restoration in agricultural landscapes. We focused in the case of Brazil, where we assessed the factors driving the proportion of land allocated to passive and active restoration in 42 programs covering 698,398 hectares of farms in the Atlantic Forest, Atlantic Forest/cerrado ecotone and Amazon; the ecological outcomes of passive and active restoration in 2955 monitoring plots placed in six restoration programs; and the legal framework developed by some Brazilian states to balance the different restoration approaches and comply with legal commitments. Active restoration had the highest proportion of land allocated to it (78.4%), followed by passive (14.2%) and mixed restoration (7.4%). Passive restoration was higher in the Amazon, in silviculture, and when remaining forest cover was over 50 percent. Overall, both restoration approaches showed high levels of variation in the ecological outcomes; nevertheless, passively restored areas had a smaller percentage canopy cover, lower species density, and less shrubs and trees (dbh > 5 cm). The studied legal frameworks considered land abandonment for up to 4 years before deciding on a restoration approach, to favor the use of passive restoration. A better understanding of the biophysical and socioeconomic features of areas targeted for restoration is needed to take a better advantage of their natural regeneration potential.     

Drought and the consequences of El Niño in Borneo: a case study of figs

Borneo has a perhumid climate but occasional severe droughts have an important impact. Droughts may affect the composition and size structure of plant communities through differential mortality or, via their impact on the availability of plant resources, affect plant–animal interactions. From January to April 1998, northern Borneo suffered a very severe drought linked to the El Niño Southern Oscillation event of 1997–1998. In this article, the impacts of this drought on the rain forest at Lambir Hills National Park, Sarawak, are considered with special reference to a keystone plant group, the figs. Small fires entered the edge of the forest from the roadside, killing saplings, climbers, and understory trees. Community-wide mortality for adult trees was 0–7 times higher than in nondrought years, with larger trees showing a greater proportional increase. In figs, mortality was significantly higher in pioneers, but hemiepiphytes and roadside species were unaffected. Phenology was substantially affected. Leaf and flower/fruit production decreased or ceased during the drought and increased suddenly following renewed rain. Pollinators of dioecious figs became locally extinct during the drought, and other plant–animal interactions may also have been disrupted. The frequency and severity of droughts has increased substantially in the past three decades, and climate models suggest this may be the result of global warming. The impacts of the 1998 drought at Lambir Hills National Park suggest that, should this trend continue, a substantial alteration of habitats and overall loss of biodiversity can be expected in Borneo.     

气候变化背景下定量解析生态工程对植被动态的影响研究方法概述

植被动态变化受气候和人类活动双重作用力的驱动。在气候变化的背景下,如何定量剖析人类活动在植被动态变化中的作用力,对增加植被生态系统碳储量和缓解气候变化具有重要意义。随着生态文明建设和环境保护意识的加强,就植被生态系统而言,生态工程作为一项巨大的人类活动,对植被影响的广度和深度日益加强。系统分析气候变化背景下生态工程对植被的生态效应影响,对后期生态恢复措施的制定和实施具有十分重要的理论指导意义。虽已有一些生态工程对植被影响的定量化研究方法,但不同方法之间的结果难以进行比较研究。比较探讨各定量研究方法的优缺点有利于推动植被驱动机制的研究,有助于恢复生态学和人类生态学的应用和发展。系统梳理了定量研究生态工程对植被动态的影响主要研究方法:回归分析、残差趋势分析、基于生物物理过程模型方法和阈值分割方法。对比发现,基于生物物理过程模型方法具有较高的应用潜力,趋势分析方法和阈值分割方法仍需进一步完善。目前,定量剖析生态工程对植被变化的影响研究主要侧重于模型模拟,野外实证研究和模型验证较为缺乏,是恢复生态学未来研究的重点和难点之一。     

Relative importance of factors controlling the success of Oxalis acetosella: an example of linear modelling in ecological research

An ecological hypothesis concerning the relative importance of factors governing the success of Oxalis acetosella on mesic upland forest sites in southern Finland was formulated and tested statistically by means of a multivariate linear model. The data consisted of a stratified random sample of 40 plots with biological measurements and associated observations on environmental variables. The covariance matrix between the incorporated variables was computed and the model parameters were estimated using the method of maximum likelihood provided by the computer programme LISREL V. The results supported the hypothesis based on previous observations and experiments: Oxalis acetosella benefits from a high nutrient level of the soil, but is decisively dependent on the shelter provided by the tree stand. When both spruce stands and well-lit pine stands on mesic and relatively rich forest sites were considered simultaneously, only a weak correlation was found between light availability and site fertility. Accordingly, the presumed value of Oxalis acetosella as an indicator of site fertility appears to be questionable. The adequacy of linear modelling in an ecological context is discussed. The kind of models applied in this study have only a limited application range in non-experimental ecological research. However, linear modelling may contribute to solving particular ecological problems in cases where short environmental gradients are considered so that nonlinearity is not a dominant feature.     

On the use of grammars in vegetation analysis

Grammars provide a means of generating large amounts of variability from relatively small resources, and seem especially relevant when the variation to be modelled is discontinuous since they describe the organisation symbols from some alphabet. In order to use grammars, it is desirable that they be inferred from observational data, and we present three examples of such inference. Two involve temporal successions, while the third is based on spatial transects of aquatic vegetation in wetlands in Victoria, Australia. The temporal successions were adequately represented by simpler regular grammars, suggesting that the processes involved may be modelled in a relatively simple manner. The spatial data requires a context-free grammar, reflecting the greater complexity of the spatial series, the uniqueness of each site, and the difficulties of modelling parallel systems with serial models. Examining the grammars further leads to some suggestions concerning the features of them which are important for ecological interpretation. It further leads to a novel view of the nature of groups in classification.     

生态修复前后祁连山地区植被覆盖变化

祁连山是我国重要的生态屏障,定量评估气候变化和人类活动对植被变化的影响对祁连山生态保护和修复具有重要意义。以祁连山地区为研究区,分析1986—2020年植被覆盖时空动态变化,计算气候变化及人类活动对植被覆盖变化的贡献率,进而评估生态修复工程对于植被覆盖变化的影响程度。结果表明：(1)1986—2020年间祁连山地区植被覆盖度呈现显著增加趋势,变化趋势为0.022/10a;中高覆盖度主要分布在东南地区,西北地区仍然是以低覆盖度为主,且1999年的退耕还林还草工程施行后,中低覆盖度向中高覆盖度方向转化。(2)祁连山地区植被覆盖变化是气候因素和人类活动共同作用的结果。气候因素对植被覆盖的贡献率为93.40%,人类活动贡献率为6.60%,气候因素是祁连山区植被变化的主导因素,但人类活动在植被变化中的影响程度逐年增加。祁连山地区植被覆盖呈转好趋势,这主要是因为退耕还林还草等生态工程极大地改善了祁连山地区的植被覆盖状况,为后续植被的恢复和生态系统的稳定奠定了良好的基础。     

延安市生态修复双赢模式实证研究

"越穷越垦、越垦越穷"的贫困陷阱是困扰全球可持续发展的学术难题之一,探索摆脱贫困陷阱的有效途径,是生态修复的核心目标。因此,生态修复不仅要依据当地气候与地理条件开展生态治理,同时要改变当地居民的生产生活行为,发展有利于生态修复的绿色产业,使当地居民的生产生活行为既可以提高收入、改善生活,又有利于生态修复。从而摆脱"越穷越垦、越垦越穷"的被动局面,实现生态修复与居民生计改善的双赢目标。为了验证这一模式的可行性,该研究在退耕还林项目实施的基础上,通过补短板的方式,在延安市开展了生态修复双赢模式实证研究。结果表明,新方案实施前,延安市NDVI增长速度是陕西省平均水平的41%;新方案实施后,是陕西省平均水平的195%,新方案的贡献率为74.0%。双赢模式较好解决了环境保护与社会经济发展彼此分离的这一矛盾,提高了生态修复的治理效果,为我国生态脆弱区精准扶贫和生态文明建设提供了理论依据和治理样板。     

Provenance variation in morphology and leaflet anatomy of Parkia biglobosa and its relation to drought tolerance

 Measurements of morphological and anatomical characteristics made on 4-month-old seedlings from five provenances of Parkia biglobosa (Jacq.) Benth., grown in a tropical greenhouse under controlled conditions, showed significant differences between the northern provenances, which represented the Sudan savanna zone, and the southern provenances which represented the forest zone of the species distribution. Seedlings of provenances from the savanna zone showed more xerophytic characteristics than those from the forest zone. They were smaller in height, with a greater number of smaller leaflets per pinnae, a lower specific leaflet mass, smaller palisade and guard cells and a lower ratio of palisade:non-palisade tissue. There were also significant differences in the same characteristics, except palisade cell length, between provenances from the easterly and westerly extremes of the species range. Stomatal conductance measured after 2 weeks of droughting also showed that provenances from the savanna zone had higher values, indicating greater physiological activity and reduced stress, compared with provenances from the forest zone. Multivariate discriminant analysis of the morphological and anatomical characteristics showed that 98% of the seedlings were classified correctly with respect to provenance. The squared distances between provenances were closely related to the geographical distances between locations. Yet, not all variation in leaf anatomy could be explained by the difference in climatic conditions from north to south. Also drought tolerance was not always related to morphological and anatomical features. It is possible that clinal variation within the species from east to west may be interacting with climatic differences from north to south. Received: 2 June 1998 / Accepted: 29 June 1998     

Gap disturbance regime and composition in the Atlantic Montane Rain Forest: the influence of topography

In the Atlantic Montane Rain Forest of south-eastern Brazil, a field study was carried out to describe the forest disturbance regime, analyse canopy gap composition and evaluate the influence of habitat parameters on gap tree species composition. We characterized canopy gaps considering the group of variables as follows: area, type and number of tree/branch falls, topographic position, soil coverage and surrounding canopy trees. Gap composition was assessed at species level by measuring all individuals inside gaps higher than one meter. Mean gap area of the 42 canopy gaps analysed was 71.9 ± 9.0 m2 (mean ± SE). Out of the studied gaps, 35.7% were created by uprooted and by snapped trees, 16.7% by dead-standing trees and 11.9% by the fall of large branches. The disturbance regime was characterized by gap openings predominantly smaller than 150 m2 and by spatial patterning related to topography. Ridges had smaller gaps and higher proportions of gaps created by branch falls; slopes had bigger gaps generally created by uprooting events. The more abundant and frequent species were shade tolerant and the more species-rich families found inside gaps did not differ from the forest as a whole. Pioneer species were rare and restricted to medium and large size classes. The Indicator Species Analysis and the Canonical Correspondence Analysis indicated gap area, topography and the percentage of soil cover by the genera Calathea and Ctenanthe were the predominant variables correlated with woody species distribution. So, topography emerged as an important issue not only to the gap disturbance regime, but also to gap colonization. In respect to the influence of gap processes on the Atlantic Montane Rain Forest regeneration, our results support the view that canopy gap events may not be working as promoters of community wide floristic shifts.     

Elevational differences in developmental plasticity determine phenological responses of grasshoppers to recent climate warming

Annual species may increase reproduction by increasing adult body size through extended development, but risk being unable to complete development in seasonally limited environments. Synthetic reviews indicate that most, but not all, species have responded to recent climate warming by advancing the seasonal timing of adult emergence or reproduction. Here, we show that 50 years of climate change have delayed development in high-elevation, season-limited grasshopper populations, but advanced development in populations at lower elevations. Developmental delays are most pronounced for early-season species, which might benefit most from delaying development when released from seasonal time constraints. Rearing experiments confirm that population, elevation and temperature interact to determine development time. Population differences in developmental plasticity may account for variability in phenological shifts among adults. An integrated consideration of the full life cycle that considers local adaptation and plasticity may be essential for understanding and predicting responses to climate change.     

近20年防风固沙重点生态功能区植被动态分析

植被是影响防风固沙生态功能的关键指标,也是检验防风固沙区生态保护成效的重要依据。由2010年国务院《全国主体功能区规划》划定的防风固沙类国家重点生态功能区、国家重点生态功能区转移支付县域综合确定研究范围。基于2000-2019年中分辨率成像光谱仪（MODIS）的叶面积指数（LAI）产品,从生态区和像元两个尺度分析近20年防风固沙重点生态功能区植被的时空变化趋势,并进一步探索气候因子对LAI的影响,以期揭示我国北方风沙区生态系统防风固沙功能的现状,为今后生态保护提供支撑。研究结果表明,2000-2019年间,研究区LAI年平均值呈现东高西低的空间格局,随着时间推移有显著增加趋势,平均增幅为0.03 m² m^-2（10a）^-1（P<0.01）。在生态区尺度,LAI在8个生态功能区均表现出不同程度的增长,且2010-2019年间LAI的增长速率高于2000-2009年的,其中,科尔沁草原生态功能区在20年间呈现最为显著的增加趋势,区域平均增幅为0.1154 m² m^-2（10a）^-1（P<0.01）。在像元尺度,近20年LAI显著增长（P<0.05）的区域面积占整个研究区植被面积的41.6%,其中,83.7%的LAI增长区域为草地,11.2%为耕地。增长区域主要集中在研究区东部,呈片状分布,研究区西部的LAI也有一定程度的增长,增长区域呈带状分布。2010-2019年LAI增长的区域面积为7.7%,明显大于2000-2009年LAI增长的区域面积。气候因子对研究区植被的影响为：研究区东部降水的增加对当地植被生长有正向的促进作用,而温度的影响则在整个研究区都较弱。除自然因素外,人为因素（防风固沙政策实施、农业技术进步等）对防风固沙功能区植被状况的改善也至关重要。研究区LAI的显著增加表明我国北方防风固沙屏障的生态功能在近20年有一定程度的提高。     

高寒生态脆弱区农户对气候变化的感知——以甘南高原为例

气候变化作为人类当前面临的最严峻挑战,已对生态脆弱区农户生计产生严重的负面影响,明确农户对气候变化的感知对于制定有效的气候变化适应政策非常关键。以甘南高原为研究区,基于入户调查数据,构建了农户对气候变化的感知度指数,分析了甘南高原农户的气候变化感知特征,并采用经济计量模型分析了影响农户气候变化感知的关键因素。结果表明:(1)甘南高原农户对气温变化的感知能力强于对降水变化的感知,并对近期发生的、规模较大、影响较严重的极端天气记忆较深;(2)农户对气候变化的严重性及可能性感知较强烈,感知到的适应成本与适应功效也较高,但感知到的自我效能较弱,其气候变化严重性、可能性、适应功效、自我效能及适应成本感知度指数分别为3.76、3.34、3.43、2.85、3.53,且农区农户对气候变化的风险感知与适应感知均最强,半农半牧区次之,纯牧区最弱;(3)气候变化信息、农户的客观适应能力、农户对社会话语的信任度、适应激励均会影响农户的气候变化感知,其中,适应激励为最关键的影响因素,其与农户的气候变化适应功效感知、自我效能感知均呈正相关,而与风险感知、适应成本感知呈负相关。最后,针对如何提高农户气候变化感知的准确度,增强农户应对气候变化的能力,提出相关的政策建议。     

Predicting the cover and richness of intertidal macroalgae in remote areas: a case study in the Antarctic Peninsula

Antarctica is an iconic region for scientific explorations as it is remote and a critical component of the global climate system. Recent climate change causes a dramatic retreat of ice in Antarctica with associated impacts to its coastal ecosystem. These anthropogenic impacts have a potential to increase habitat availability for Antarctic intertidal assemblages. Assessing the extent and ecological consequences of these changes requires us to develop accurate biotic baselines and quantitative predictive tools. In this study, we demonstrated that satellite‐based remote sensing, when used jointly with in situ ground‐truthing and machine learning algorithms, provides a powerful tool to predict the cover and richness of intertidal macroalgae. The salient finding was that the Sentinel‐based remote sensing described a significant proportion of variability in the cover and richness of Antarctic macroalgae. The highest performing models were for macroalgal richness and the cover of green algae as opposed to the model of brown and red algal cover. When expanding the geographical range of the ground‐truthing, even involving only a few sample points, it becomes possible to potentially map other Antarctic intertidal macroalgal habitats and monitor their dynamics. This is a significant milestone as logistical constraints are an integral part of the Antarctic expeditions. The method has also a potential in other remote coastal areas where extensive in situ mapping is not feasible.