Global Warming： Can Existing Reserves Really Preserve Current Levels of Biological Diversity？

Peleoecologlcel evidence end peleoclimatlc records indicate that there wee e plant polewerd migration in latitude and an upward shift In elevation with increased temperatures after the last glaciation. Recent studies have shown that global warming over the past 100 years has been having a noticeable effect on living systems. Current global warming Is causing a poleward and upward shift In the range of many plants and animals. Climate change, In connection with other global changes, is threatening the survival of a wide range of plant and animal species. This raises the question： can existing reserves really preserve current levels of biological diversity In the long term given the present rapid pace of climate change？ The present paper deals with this question In the context of the responses of plants and animals to global climate change, based on a literature review. Consequently, we recommend expanding reserves towards the poles and/or towards higher altitudes, to permit species to shift their ranges to keep pace with global warming.     

A trait-based approach to assess climate change sensitivity of freshwater invertebrates across Swedish ecoregions

Freshwater habitats and organisms are among the most threatened on Earth, and freshwater ecosystems have been subject to large biodiversity losses. We developed a Climate Change Sensitivity （CCS） indicator based on trait information for a selection of stream- and lake-dwelling Ephemeroptera, Plecoptera and Trichoptera taxa. We calculated the CCS scores based on ten species traits identified as sensitive to global climate change. We then assessed climate change sensitivity between the six main ecoregions of Sweden as well as the three Swedish regions based on lilies. This was done using biological data from 1,382 stream and lake sites where we compared large-scale （ecoregional） patterns in climate change sensitivity with potential future exposure of these ecosystems to increased temperatures using ensemble-modelled future changes in air temperature. Current （1961-1990） measured temperature and ensemble-modelled future （2100） temperature showed an increase from the northernmost towards the southern ecoregions, whereas the predicted temperature change increased from south to north. The CCS indicator scores were highest in the two northernmost boreal ecoregions where we also can expect the largest global climate change-induced increase in temperature, indicating an unfortunate congruence of exposure and sensitivity to climate change. These results are of vital importance when planning and implementing management and conservation strategies in freshwater ecosystems, e.g., to mitigate increased temperatures using riparian buffer strips. We conclude that traits information on taxa specialization, e.g., in terms of feeding specialism or taxa having a preference for high altitudes as well as sensitivity to changes in temperature are important when assessing the risk from future global climate change to freshwater ecosystems [Current Zoology 60 （2）： 221-232, 2014].     

The response of peatlands to climate warming: A review

Peatlands hold a large portion of the Earth’s terrestrial organic carbon and serve as important pools in the global carbon cycle. Due to their strong feedbacks, peatlands are one of the most important ecosystems with respect to climate warming. This paper reviews the effects of climate warming on peatland ecosystems. Climate warming will shift the point in time when vascular peatland plants flower and reach maximum biomass to an earlier date. Flower production for some plants will increase, but how the phenology of peatland bryophytes will react is still unknown. Climate warming may increase productivity of peatlands, especially ombrotrophic Sphagnum bogs, but in the long run the negative effects from decreased water availability may prevail. Climate warming will change the basic characteristics of peatlands: their wetness and the related cold environment and nutrient shortage. By increased mineralization and nitrogen and phosphorus availability, climate warming will facilitate the growth of vascular plants. This will suppress endangered plant species (which usually grow in low-productive, phosphorus-limited habitats) and lead to a change in vegetation composition and a decrease in peatland biodiversity. Climate warming will change the competitive balance between bryophytes and between Sphagnum and vascular plants. Climate warming in the Late Pleistocene facilitated the initiation of peatland formation, but most current experiments show an obvious tendency for climate warming to drive many peatlands to regressive succession with a shift in dominance from Sphagnum to vascular plants. This change in vegetation will increase the flux of CH₄ and possibly also CO₂. The effect of accelerated peat decay as a result of climate warming will vary between types of peatlands. Since climate warming will generally enhance peat respiration more than net primary production, more and more peatlands will become carbon sources rather than carbon sinks, which will aggravate climate warming by positive feedback. Finally, this paper addresses some problems with current manipulative experimental studies on peatland response to climate warming and makes suggestions for further studies.     

The response of peatlands to climate warming: A review

Peatlands hold a large portion of the Earth’s terrestrial organic carbon and serve as important pools in the global carbon cycle. Due to their strong feedbacks, peatlands are one of the most important ecosystems with respect to climate warming. This paper reviews the effects of climate warming on peatland ecosystems. Climate warming will shift the point in time when vascular peatland plants flower and reach maximum biomass to an earlier date. Flower production for some plants will increase, but how the phenology of peatland bryophytes will react is still unknown. Climate warming may increase productivity of peatlands, especially ombrotrophic Sphagnum bogs, but in the long run the negative effects from decreased water availability may prevail. Climate warming will change the basic characteristics of peatlands: their wetness and the related cold environment and nutrient shortage. By increased mineralization and nitrogen and phosphorus availability, climate warming will facilitate the growth of vascular plants. This will suppress endangered plant species (which usually grow in low-productive, phosphorus-limited habitats) and lead to a change in vegetation composition and a decrease in peatland biodiversity. Climate warming will change the competitive balance between bryophytes and between Sphagnum and vascular plants. Climate warming in the Late Pleistocene facilitated the initiation of peatland formation, but most current experiments show an obvious tendency for climate warming to drive many peatlands to regressive succession with a shift in dominance from Sphagnum to vascular plants. This change in vegetation will increase the flux of CH₄ and possibly also CO₂. The effect of accelerated peat decay as a result of climate warming will vary between types of peatlands. Since climate warming will generally enhance peat respiration more than net primary production, more and more peatlands will become carbon sources rather than carbon sinks, which will aggravate climate warming by positive feedback. Finally, this paper addresses some problems with current manipulative experimental studies on peatland response to climate warming and makes suggestions for further studies.     

辽东栎林净初级生产力对气候变化情景响应的模拟与分析

An ecosystem process model, BIOME-BGC, was used to explore the sensitivity of net primary productivity (NPP) of an oak (Quercus liaotungensis Koidz) forest ecosystem in Beijing area to global climate changes caused by increasing atmospheric CO₂ concentrations. Firstly we tested the model, and validated the modeled outputs using observational data; the outputs of BIOME-BGC model were consistent with observed soil water content and annual NPP. Secondly the potential impacts of climate change on the oak forest ecosystem were predicted with BIOME-BGC model. We found that the simulated NPP was much more sensitive to a 20% precipitation increase or a doubling of atmospheric CO₂ from 355 to 710 祄ol/mol than to a 2 ℃ temperature increase. Our results also indicated that the effects of elevated CO₂ and climate change on the response of NPP were not interactive.     

Climate-influenced boreotropical survival and rampant introgressions explain the thriving of New World grapes in the north temperate zone

The north temperate region was characterized by a warm climate and a rich thermophilic flora before the Eocene, but early diversifications of the temperate biome under global climate change and biome shift remain uncertain. Moreover, it is becoming clear that hybridization/introgression is an important driving force of speciation in plant diversity. Here, we applied analyses from biogeography and phylogenetic networks to account for both introgression and incomplete lineage sorting based on geno...     

Tree Rings and Ecology

Tree rings have long been recognized as a useful indicator of past environmental changes. Besides traditional applications in studies of climate change and archaeology, the technique of dendrochronology has been widely used in answering ecological questions. This has been partly reflected by the broad topics on tree rings and ecology presented at the 7th International Conference on Dendrochronology （ICD）, which was held in Beijing, June 11-17 2006. At this conference, Dr Henri Grissono-Mayer, the plenary speaker for the theme, defined dendroecology as the science that uses tree rings, dated to their exact year of formation, to analyze temporal and spatial relationships between living organisms and their environment.     

Ecological characteristics of Abies georgei population at timberline on the north-facing slope of Baima Snow Mountain, Southwest China

Abies georgei is one of the endemic trees at timberline on Qinghai-Tibetan Plateau, but little research has been done about its timberline population. One plot was set up at timberline above 4400 m on the north-facing slope of Baima Snow Mountain in Southwest China, covering an area of 0.8 hm2. Height, DBH (diameter at breast high) or root-collar diameter of seedlings and saplings, and position were recorded for each individual. The population showed a growing trend and the number of individuals decreased with increase of DBH. The survival curve can be described by Deevy-III. The population had 2 distinct peaks of mortality: age I (seedlings, DBH = 0–5 cm) and age V-VI (DBH = 20–30 cm). The highest mortality of seedlings was due to severe climate at timberline. As the saplings grew up, the interspecific and intraspecific competition resulted in another mortality peak. Through SPPA (spatial point pattern analysis), individuals of all age-classes showed uniform, random or clumped distribution with the change of scales; however, they had mainly clumped distribution. Moreover, the relationships between individuals in different age-classes were all significantly correlated with each other. Seedlings showed the highest clumping intensity and scale.     

Effects of permafrost degradation on ecosystems

Permafrost, covering approximately 25% of the land area in the Northern Hemisphere, is one of the key components of terrestrial ecosystem in cold regions. As a product of cold climate, permafrost is extremely sensitive to climate change. Climate warming over past decades has caused degradation in permafrost widely and quickly. Permafrost degradation has the potential to significantly change soil moisture content, alter soil nutrients availability and influence on species composition. In lowland ecosystems the loss of ice-rich permafrost has caused the conversion of terrestrial ecosystem to aquatic ecosystem or wetland. In upland ecosystems permafrost thaw has resulted in replacement of hygrophilous community by xeromorphic community or shrub. Permafrost degradation resulting from climate warming may dramatically change the productivity and carbon dynamics of alpine ecosystems. This paper reviewed the effects of permafrost degradation on ecosystem structure and function. At the same time, we put forward critical questions about the effects of permafrost degradation on ecosystems on Qinghai–Tibetan Plateau, included: (1) carry out research about the effects of permafrost degradation on grassland ecosystem and the response of alpine ecosystem to global change; (2) construct long-term and located field observations and research system, based on which predict ecosystem dynamic in permafrost degradation; (3) pay extensive attention to the dynamic of greenhouse gas in permafrost region on Qinghai–Tibetan Plateau and the feedback of greenhouse gas to climate change; (4) quantitative study on the change of water-heat transport in permafrost degradation and the effects of soil moisture and heat change on vegetation growth.     

Effects of permafrost degradation on ecosystems

Permafrost, covering approximately 25% of the land area in the Northern Hemisphere, is one of the key components of terrestrial ecosystem in cold regions. As a product of cold climate, permafrost is extremely sensitive to climate change. Climate warming over past decades has caused degradation in permafrost widely and quickly. Permafrost degradation has the potential to significantly change soil moisture content, alter soil nutrients availability and influence on species composition. In lowland ecosystems the loss of ice-rich permafrost has caused the conversion of terrestrial ecosystem to aquatic ecosystem or wetland. In upland ecosystems permafrost thaw has resulted in replacement of hygrophilous community by xeromorphic community or shrub. Permafrost degradation resulting from climate warming may dramatically change the productivity and carbon dynamics of alpine ecosystems. This paper reviewed the effects of permafrost degradation on ecosystem structure and function. At the same time, we put forward critical questions about the effects of permafrost degradation on ecosystems on Qinghai–Tibetan Plateau, included: (1) carry out research about the effects of permafrost degradation on grassland ecosystem and the response of alpine ecosystem to global change; (2) construct long-term and located field observations and research system, based on which predict ecosystem dynamic in permafrost degradation; (3) pay extensive attention to the dynamic of greenhouse gas in permafrost region on Qinghai–Tibetan Plateau and the feedback of greenhouse gas to climate change; (4) quantitative study on the change of water-heat transport in permafrost degradation and the effects of soil moisture and heat change on vegetation growth.     

太白山林线附近太白红杉种群的生态特征

高山林线对外界环境的变化和干扰异常敏感,已成为全球气候变化研究的热点。太白红杉(Larix chinensis)是太白山的高山林线树种,对高海拔生态环境的保护起着重要的作用。在太白山林线附近采用样方调查的方法,对太白红杉种群的生态特征进行了研究,结果表明:(1)林线附近不同海拔区域,种群的平均基径、平均胸径、平均树高等基本特征随着海拔的升高明显降低。(2)太白红杉的胸径与年龄存在着较明显的回归关系,而树高与年龄相关性较低。随着海拔的升高,回归方程的拟合优度呈下降趋势。(3)林线附近不同海拔区域,太白红杉种群的径级结构与年龄结构均存在一定的波动。表明该区域存在着波形的更新,可能与太白红杉的年龄结构受外界环境的影响较大有关。(4)太白红杉种群各龄级的空间格局基本上是聚集型。随着取样尺度的增加,聚集强度呈增加的趋势。随年龄增加,种群分布由聚集型向随机型过渡,聚集强度减弱。     

高山林线与气候变化关系研究进展

20世纪全球气候经历了异常的变化。20世纪是过去1000年中增暖最大的1个世纪,并且90年代是最暖的10年。作为两个生态系统的过渡地带,生态过渡带是监测全球变化的重要地点,而森林和苔原之间的高山林线是全球变化最为敏感的地点。从高山林线树木个体对气候变化的响应、气候变化下林线处树木的更新、林线格局变化以及高山林线与气候变化关系研究中所采用的研究方法等方面,综合论述了国内外的研究进展,最后提出了高山林线研究中需要注意的问题,并对今后的研究趋势作了展望。     

干扰对高山林线再形成过程的影响

高山林线是一类典型的生态交错带,因其特殊的结构和功能以及对外界环境的高度敏感性而成为全球气候变化研究的热点之一.本文简要介绍了高山林线的相关概念及其界定,从高山林线海拔位置波动、植被格局变化、生态交错带物种组成变化及其生理生态特征变化等几个方面阐述了干扰对高山林线再形成过程的不同影响,总结了高山林线物种对干扰的两种基本响应方式,即退行和入侵.认为人为干扰在一定程度上弱化了当前气候变暖对高山林线波动的影响,因而在不同地区必须紧密结合当地可能的干扰来讨论高山林线的波动,否则结果有可能因误差较大而失去应有的价值.指出该研究在高海拔地区进行植被恢复的指导意义.     

气候变暖对老秃顶子林线结构特征的影响

运用样带样方法和年轮气候学方法对大海林地区的气候因子和样地数据进行了分析。结果表明 ,近 30 a来老秃顶子地区气候变暖明显 ,尤其是冬季增温最明显 ,月份增温中以 2月份最大 ;寒冷时期 (12月份、翌年 1和 2月份 )和温暖时期 (6～ 9月份 )的温度都有增加 ,但是寒冷时期温度的增加幅度较大 ;冬季与夏季温差稍有减少 ,但积温有所增加 ,整年的热量正在增加。全球变暖导致的大海林地区增温对老秃顶子林线结构特征产生了很大的影响 ,由样地调查和分析可知 ,全球变暖导致林线中上部幼苗、幼树的更新和存活增多 ,森林密度加大 ,树木平均年龄降低 ,年龄结构呈倒 J字型 ,并且多呈聚集分布 ;而在林线的下部 ,幼苗更新很少 ,主要以中龄林存在 ,并且多呈零散分布形式。通过年轮分析得出 ,气候变暖导致林线树木径生长和高生长增加 ,而且增加的趋势和近 30 a来温度的变化基本一致。通过对年轮指数与气候因子的相关性分析 ,表明林线树木年轮指数与温度的相关性较强 ,而与降水的相关性较弱 ,并且年轮指数与温暖时期温度和积温呈正相关 ,而与寒冷时期温度和年平均温度呈负相关 ,表明温暖时期温度和积温控制着林线的海拔高度 ,而寒冷时期的温度和年平均温度主要对林线树种类型起着决定性的作用。从敏感度分析看出 ,林线     

Long‐term forest resilience to climate change indicated by mortality,regeneration, and growth in semiarid southern Siberia

Several studies have documented that regional climate warming and the resulting increase in drought stress have triggered increased tree mortality in semiarid forests with unavoidable impacts on regional and global carbon sequestration. Although climate warming is projected to continue into the future, studies examining long‐term resilience of semiarid forests against climate change are limited. In this study, long‐term forest resilience was defined as the capacity of forest recruitment to compensate for losses from mortality. We observed an obvious change in long‐term forest resilience along a local aridity gradient by reconstructing tree growth trend and disturbance history and investigating postdisturbance regeneration in semiarid forests in southern Siberia. In our study, with increased severity of local aridity, forests became vulnerable to drought stress, and regeneration first accelerated and then ceased. Radial growth of trees during 1900–2012 was also relatively stable on the moderately arid site. Furthermore, we found that smaller forest patches always have relatively weaker resilience under the same climatic conditions. Our results imply a relatively higher resilience in arid timberline forest patches than in continuous forests; however, further climate warming and increased drought could possibly cause the disappearance of small forest patches around the arid tree line. This study sheds light on climate change adaptation and provides insight into managing vulnerable semiarid forests.     

Upper range limit establishment after wildfire of an obligate-seeding montane forest tree fails to keep pace with 20th century warming

Aims How species respond to climate change at local scales will depend on how edaphic and biological characteristics interact with species physiological limits and traits such as dispersal. Obligate seeders, those species that depend on fire for recruitment, have few and episodic opportunities to track a changing climate envelope. In such cases, long-distance seed dispersal will be necessary to take advantage of rare recruitment opportunities. We examine recruitment patterns and seedling growth below, at and above the timberline of an obligate-seeding Australian montane forest tree (Eucalyptus delegatensis) after stand-replacing fire, and place these changes in the context of regional warming.Methods We use two methods to detect whether E. delegatensis can establish and persist above the timberline after stand-replacing wildfire in montane forests in south-east Australia. First, we examine establishment patterns by using belt transects at six sites to quantify how changes in post-fire recruit density with increasing distance above the timberline seven years post-fire. Second, to determine whether dispersal or physiological constraints determine post-fire establishment patterns, we transplanted seedlings and saplings into bare ground above (100 m elevation), at, and below (50 m elevation) timberline 18-months after fire. We monitored seedling growth and survival for one growing season.Important findings There was minimal upslope migration of the species after fire with most saplings observed near seed-bearing timberline trees, with only occasional outpost saplings. Transplanted seedlings and saplings survived equally well across one growing season when planted above existing timberlines, relative to saplings at or below the timberline. Seedling and sapling growth rates also did not differ across these location, although seedlings grew at much faster rates than saplings. These findings suggest that upslope growing season conditions are unlikely to limit initial range expansion of trees after fire. Instead, it is more likely that seed traits governing dispersal modulate responses to environmental gradients, and global change more generally.     

山西五台山高山林线的植被景观

 过草本植物群落的分类和排序,结合对乔木和灌木分布的分析,确定了五台山高山林线的几条植被界线以及五台山森林上限附近植被的性质。结果表明：1）阳坡林线的海拔范围为2 605～2 790 m,阴坡林线的海拔范围为2 810～3 015 m;2）草本植物群落随海拔高度的变化比较明显,阴坡和阳坡从郁闭林到山顶均依次分布林下草本层、林缘草甸、亚高山灌丛草甸、高山草甸,草本植物的分布很好地体现了林线内部景观的差异性;3）海拔高度是高山林线附近草本植物群落空间分异的决定性因素。     

高山林线生态交错区木本植物幼苗分布特征、更新机制及其对气候变化的响应

木本植物幼苗是高山林线生态交错区的重要组成部分,其更新对气候变化背景下树线的移动至关重要.本研究通过对近几十年来全球范围内林线生态交错区的木本植物幼苗分布特征、更新机制及其对气候变化响应的研究总结得出:林线生态交错区木本植物幼苗的空间分布类型主要为渐变型和聚集型,且不同分布类型对树线动态的指示意义各异.在全球尺度上,其分布的海拔高限通常与生长季长度、均温和物种特性等有关,而在区域尺度上则多受降水影响.在幼苗更新初期,种源在很大程度上决定了种子的萌发及分布位置,之后微环境的促进作用为幼苗的定植提供庇护,提高其存活率,而在更新后期多种生物和非生物因素及其相互作用则非常关键.气候变暖促使林线生态交错区气温升高、降水充沛,有利于幼苗生长,使其向高海拔区域扩张而成为树线上移的先兆,但部分物种受遗传特性或适应策略影响,仅表现为密度增加,使树线保持相对稳定.未来应借助树轮、14C等精确定年技术,通过长期的野外定位观测和室内模拟,加强多时空尺度下林线幼苗的空间分布特征和更新机制研究,分析不同类型林线内木本植物幼苗的适应策略,预测气候变化背景下的树线动态,为山地生态系统恢复及保护提供科学依据.     

气候变暖对陆地植被-土壤生态系统的影响研究

由于自然因素及人类活动的长期影响,全球气候变化已经成为不容置疑的事实,并对陆地生态系统的植被及土壤产生了深远影响。陆地植被一土壤生态系统在全球气候变化中的反应与适应等过程已成为众多科学家所关注的问题。为更好地了解陆地植被一土壤生态系统对全球气候变化的响应机制,综述了气候变暖对植物的物候与生长、光合特征、生物量生产与分配,以及土壤呼吸等方面的影响,并对分析得到的结论进行了总结。分析指出,随着全球气候变暖,植物个体和群落特征以及土壤特性都会发生相应改变,高海拔地区的植被高度有增加趋势,而低海拔地区的植被可能出现矮化。然而,在以下方面还存有不确定性：（1）气候变暖导致的植被特征变化是否会减弱全球气候变化;（2）在较长时间尺度上气候变暖如何影响植物的物候和生长,特别是植物的体型;（3）高寒生态系统冬季土壤呼吸对气候变暖如何响应。     

Growth trends and climate responses of Norway spruce along elevational gradients in East-Central Europe

Key message

Decadal growth variability of Norway spruce increases with elevation. Recent temperature sensitivity and growth enhancement are limited to trees growing in the zone adjacent to timberline.

Abstract

Growth trends and climate responses of forest trees along elevational gradients are not fully understood. A deeper insight is, however, fundamental for predicting ecosystem functioning and productivity under future climate change. Supplementary to the effects of elevation and regional provenance on tree growth are sample depth, uneven representation of sample age and varying site conditions. Furthermore, there is only a limited number of studies addressing growth changes along elevational gradients, while at the same time applying tree-ring standardization methods that are sensitive to trend preservation. Here, we introduce 12 novel tree-ring width chronologies of Norway spruce (Picea abies[L.] Karst.) from four elevational belts encompassing montane forests and the local timberline in three regions in East-Central Europe between 15° and 19°E. Each chronology is characterized by sufficient sample replication and a comparable age structure between 1906 and 2010. Tree growth near timberline revealed substantial medium-frequency variability and sharply increasing ring widths since the 1980s. Medium-frequency growth variability of lower elevation trees was, however, relatively small, and growth rates over the last decade were either stable or even decreased. During the last four decades, Norway spruce from higher elevations exhibited a reduced response to autumn temperatures preceding ring formation. In contrast, trees from the lower-montane zone increased their sensitivity to drought during the same time. Our results emphasize not only different but also instable growth trends and climate responses of forest trees along altitudinal gradients, which should be considered in future forest management strategies.