Impact of climate change on vulnerability of forests and ecosystem service supply in Western Rhodopes Mountains

The vulnerability of forest ecosystem services to climate change is expected to depend on landscape characteristic and management history, but may also be influenced by the proximity to the southern range limit of constituent tree species. In the Western Rhodopes in South Bulgaria, Norway spruce is an important commercial species, but is approaching its current southern limit. Using climate sensitive forest models, we projected the impact of climate change on timber production, carbon storage, biodiversity and soil retention in two representative landscapes in the Western Rhodopes; a lower elevation landscape (1000–1450 m a.s.l) dominated by mixed species forests, and a higher elevation landscape (1550–2100 m a.s.l.) currently dominated by spruce. In both landscapes climate change is projected to induce a shift in forest composition, with drought-sensitive species, such as Norway spruce, being replaced by more drought-tolerant species such as Scots pine and black pine at lower elevations. In the higher elevation landscape a reduction in spruce growth is projected, particularly under the more severe climate change scenarios. Under most climate scenarios a reduction in growing stock is projected to occur, but under some scenarios a moderate increase in higher elevation stands (>1500 m a.s.l.) is expected. Climate change is projected to negatively influence carbon storage potential across landscapes with the magnitude depending on the severity of the climate change scenario. The impact of climate change on forest diversity and habitat availability is projected to differ considerably between the two landscapes, with diversity and habitat quality generally increasing at higher elevations, and being reduced at lower elevations. Our results suggest that if currently management practices are maintained the sensitivity of forests and forest ecosystem services in the Western Rhodopes to climate change will differ between low and higher elevation sites and will depend strongly on current forest composition.     

Accurate modeling of harvesting is key for projecting future forest dynamics: a case study in the Slovenian mountains

Maintaining the provision of multiple forest ecosystem services requires to take into consideration forest sensitivity and adaptability to a changing environment. In this context, dynamic models are indispensable to assess the combined effects of management and climate change on forest dynamics. We evaluated the importance of implementing different approaches for simulating forest management in the climate-sensitive gap model ForClim and compared its outputs with forest inventory data at multiple sites across the European Alps. The model was then used to study forest dynamics in representative silver fir–European beech stands in the Dinaric Mountains (Slovenia) under current management and different climate scenarios. On average, ForClim accurately predicted the development of basal area and stem numbers, but the type of harvesting algorithm used and the information for stand initialization are key elements that must be defined carefully. Empirical harvesting functions that rigorously impose the number and size of stems to remove fail to reproduce stand dynamics when growth is just slightly under- or overestimated, and thus should be substituted by analytical thinning algorithms that are based on stochastic distribution functions. Long-term simulations revealed that both management and climate change negatively impact conifer growth and regeneration. Under current climate, most of the simulated stands were dominated by European beech at the end of the simulation (i.e., 2150 AD), due to the decline of silver fir and Norway spruce caused mainly by harvesting. This trend was amplified under climate change as growth of European beech was favored by higher temperatures, in contrast to drought-induced growth reductions in both conifers. This forest development scenario is highly undesired by local managers who aim at preserving conifers with high economic value. Overall, our results suggest that maintaining a considerable share of conifers in these forests may not be feasible under climate change, especially at lower elevations where foresters should consider alternative management strategies.     

Climate changes and tree stand dynamics at the upper limit of their growth in the North Ural mountains

The composition and structure of tree stands near the timberline have been studied on different slopes and at different elevations in the Tylaisko-Konzhakovsko-Serebryanskii Massif, the North Urals. It has been found that the upper limits of tree stands with different degrees of canopy closure have risen considerably (by about 100 m of elevation) since the mid-19th century, although the formation of these stands started as early as the late 18th century. Woodless areas in the eastern part of the massif started to be colonized by Larix sibirica in the late 18th to early 19th centuries; those in the western part, by Picea obovata in the mid-19th century; and in the southern part, by Betula tortuosa in the late 19th century. Analysis of meteorological data provides evidence for warming and increasing humidity of the climate since the late 19th century. Favorable climatic changes that facilitated the expansion of the forest have taken place both in the summer (prolongation of the growing period) and in winter seasons (increase of air temperature and precipitation). The observed differences in the composition and dynamics of tree stands between the studied areas of the mountain range are most probably explained by different requirements of tree species for the depth of snow cover and the degree of soil freezing.     

Sustainable forest management in a mountain region in the Central Western Carpathians,northeastern Slovakia: the role of climate change

European forestry is facing many challenges, including the need to adapt to climate change and an unprecedented increase in forest damage. We investigated these challenges in a Norway spruce-dominated mountain region in Central Europe. We used the model Sibyla to explore forest biomass production to the year 2100 under climate change and under two alternative management systems: the currently applied management (CM), which strives to actively improve the forest’s adaptive capacity, and no management (NM) as a reference. Because biodiversity is thought to have mostly positive effects on the adaptive capacity of forests and on the quality of ecosystem services, we explored how climate change and management affect indicators of biodiversity. We found a differential response across the elevation-climatic gradient, including a drought-induced decrease in biomass production over large areas. With CM, the support of non-spruce species and the projected improvement of their growth increased tree species diversity. The promotion of species with higher survival rates led to a decrease in forest damage relative to both the present conditions and NM. NM preserved the high density of over-matured spruce trees, which caused forest damage to increase. An abundance of dead wood and large standing trees, which can increase biodiversity, increased with NM. Our results suggest that commercial spruce forests, which are not actively adapted to climate change, tend to preserve their monospecific composition at a cost of increased forest damage. The persisting high rates of damage along with the adverse effects of climate change make the prospects of such forests uncertain.     

Models of taiga-steppe communities on the western coast of Lake Baikal

As a result of monitoring spatial changes in the cenotic structure of plant communities at the taiga-extrazonal steppe boundary on the western coast of Lake Baikal, models of taiga-steppe communities reflecting the formation, dynamics, and genesis of forests in the taiga zone have been constructed. Changes in the species composition of communities, mesophytization of steppes, the expansion of moss synusiae characteristic of polydominant dark conifer and light conifer taiga forests, active forest invasion into steppe areas, and the presence of dark conifer tree species in light conifer forests have been revealed.     

Differences in plant species diversity between conifer (<Emphasis Type="Italic">Pinus tabulaeformis</Emphasis>) plantations and natural forests in middle of the Loess plateau

We compared differences in plant species diversity between conifer (Pinus tabulaeformis) plantations and natural secondary forests in the middle of the Loess plateau. The goal of the study was to examine the differences in the effect of stand development on species diversity and in species responses to changes between forest types and between forest layers. To clarify the effects of differences in forest management, we emphasized the functional types of plant species occurring in each forest type. The result as follow: (1) The H′ and S of tree layer were significantly lower in natural conifer forest than old conifer and secondary forest, but were not different compared with mid aged conifer forest. The H′ and S of shrub layer were significantly lower in mid aged conifer forest compared with other forest types. The H′ of herb layer showed no significant differences in the four forest types. The evenness index (J′) of tree layer of mid aged conifer forest was lower than other forest communities and its J′ of shrub layer was highest although its richness of shrub layer was lower than in the other forest types. (2) The analysis of β diversity index also indicated large differences between conifer plantations and natural forests. Although the tree layer species were similar in old plantation and natural conifer forests, they differed greatly between the natural conifer and secondary forests. The natural conifer and secondary forest species composition in shrub layer differed significantly from those in plantation and secondary plots. Tree species were significantly less common in plantations than in abandoned coppice forests. Species composition in the herb layer of different forest types was similar. (3) The management of P. tabulaeformis plantations alters plant species composition considerably; the number of sub tall-tree species is increased in old aged conifer forest, especially species dispersed by animals. Plantation management appears to affect ecological processes through seed dispersal. From the perspective of management, the change in the structure and composition of the canopy in plantations could affect the behavior of dispersers and regeneration.     

Changes in the dry tropical forests in Central India with human use

Understanding changes in forest composition and structure is important to help formulate effective policies that promote future ability of forests to provide local livelihood needs, habitat and ecosystem services. This is particularly important in dry tropical forests that are ecologically different from other forests and are heavily used by local, forest-dependent residents. In this study, we identify biophysical, demographic and use factors associated with differences in species diversity, vegetation structure (abundance at different size classes), biomass and relative abundance of species across the Kanha–Pench landscape in Central India. We sampled vegetation in twenty transects across different human and livestock population densities and frequencies of use. We found that biomass, species diversity and vegetation (abundance at different size classes) are negatively associated with increasing population density, and species composition at different size classes is significantly different at higher frequencies of use at low population densities. Lack of difference in species composition at high population densities may be due to colonization and growth of individuals at some of these sites due to creation of new ecological niches and gaps at high human use. Relative abundance of species at different size classes also varies with frequency of use and population density. Results suggest that human use is altering relative abundance of species, which may change long-term forest composition and thus alter biomass and vegetation structure of the forest. We conclude that human use is an agent in altering long-term composition that can alter availability of tree species for local use and other ecosystem services.     

南京紫金山马尾松树轮δ13C对气候变化响应敏感性的研究

树木年轮宽度指标在气候重建中发挥了重要的作用，可是在温暖湿润的地区，利用树木年轮宽度重建古气候遇到了困难。因此寻找其他代用指标就成为一项急迫而重要的任务。一些研究发现，树轮稳定碳同位素可以发挥重要的作用。但是，是否所有的树种的树轮碳同位素对气候的响应都同样的敏感，还需要通过大量的研究分析工作来验证。为了了解温暖湿润的亚热带季风区马尾松树轮δ13C对气候响应的敏感性，选取了南京紫金山的两个马尾松树盘，进行了树轮δ13C的分析，建立了1939~2002和1955~2002年两个树轮δ13C变化序列。与降水、温度、相对湿度、光照时数、风速等气候指标进行了相关分析。结果表明：（1）马尾松树轮δ13C对于气候的响应是敏感的，可以作为气候变化的代用指标；（2）坡向对于马尾松树轮δ13C对气候的响应敏感性也有一定的影响，树轮δ13C平均值西南坡比东南坡高，西南坡比东南坡对月平均最低和最高温度的响应更敏感；（3）紫金山马尾松树轮δ13C与该地区生长季（尤其是夏、秋季）的月平均气温、月平均最高气温和日照时数呈正相关，而与月平均最低气温、降水量、空气相对湿度呈负相关     

Climatic changes and their impact on socio-economic sectors in the Bhutan Himalayas: an implementation strategy

This paper contributes to an enhanced understanding of present climatic conditions, observed climate trends and regional climate vulnerability of the Bhutan Himalayas. Bhutan’s complex, often high-altitude terrain and the severe impact of the Indian summer monsoon leads to a strong exposure of the countries’ key economic sectors (agriculture, forestry, hydropower generation and tourism) to climatic changes. Climate change also threatens Bhutan’s vast biodiversity and increases the likelihood of natural hazards (e.g. glacier lake outburst floods, flash floods, droughts and forest fires). A better understanding of Bhutan’s climate and its variability, as well as observed and possible climate impacts, will help in improving the handling of regional social, economic and ecologic challenges not limited to the Himalayas. Only a few climatological studies exist for the eastern Himalayas. They mainly focus on adaptation to immediate threats by glacier lake outbursts. In contrast, this paper (1) investigates the average spatial and inner-annual diversity of the air temperature regime of Bhutan, based on local meteorological observations, (2) discusses past temperature variability, based on global datasets, and (3) relates effects of observed warming to water availability, hydropower development, natural hazards, forests, biodiversity, agriculture, human health and tourism in the Bhutan Himalayas. Results indicate a large spatial and temporal temperature variability within Bhutan and considerably increasing temperatures especially over recent decades. Implications of regional climatic changes on various socio-economic sectors and possible adaptation efforts are discussed.     

Dynamics of snowmelt water composition in conifer forests exposed to airborne industrial pollution

An analysis is made of the spatial variability of snowmelt water composition (within and between biogeocenoses), with regard to its long-term dynamics, in pine and spruce forests exposed to airborne industrial pollution from the Europe’s largest Severonikel Copper–Nickel Smelter Complex. Snowmelt waters from under the tree canopy, compared to those from intercrown areas, contain higher concentrations of chemical elements due to their washing and leaching from tree crowns. This is especially true of spruce forests, since the crowns of spruce trees have a high sorption capacity. Distinct trends in the long-term dynamics of snowmelt water composition, related to reduction of industrial emissions, are observed in background forest areas and defoliating forests but not in the vicinity of pollution sources. It is shown that the main factors determining these dynamics in forests of the Kola Peninsula are edificator tree species, airborne industrial pollution, and, possibly, an increase in the number of days with above-zero temperatures in the period of snow accumulation, which facilitates washing and leaching of chemical compounds from tree crowns.     

Projecting canopy cover change in Tasmanian eucalypt forests using dynamically downscaled regional climate models

Loss of forest cover is a likely consequence of climate change in many parts of the world. To test the vulnerability of eucalypt forests in Australia’s island state of Tasmania, we modelled tree canopy cover in the period 2070–2099 under a high-emission scenario using the current climate–canopy cover relationship in conjunction with output from a dynamically downscaled regional climate model. The current climate–canopy cover relationship was quantified using Random Forest modelling, and the future climate projections were provided by three dynamically downscaled general circulation model (GCM) simulations. Three GCMs were used to show a range of projections for the selected scenario. We also explored the sensitivity of key endemic and non-endemic Tasmanian eucalypts to climate change. All GCMs suggested that canopy cover should remain stable (proportional cover change <10 %) across ~70 % of the Tasmanian eucalypt forests. However, there were geographic areas where all models projected a decline in canopy cover due to increased summer temperatures and lower precipitation, and in addition, all models projected an increase in canopy cover in the coldest part of the state. The model projections differed substantially for other areas. Tasmanian endemic species appear vulnerable to climate change, but species that also occur on the mainland are likely to be less affected. Given these changes, restoration and carbon sequestration plantings must consider the species and provenances most suitable for future, rather than present, climates.     

Environmental and climatic signals from stable isotopes in Anatolian tree rings, Turkey

Dendrochronological and oxygen–carbon isotopic analysis was conducted on tree rings collected at two different elevations from three different regions in western Anatolia, Turkey. Tree rings were sampled from Anatolian black pines (Pinus nigra Arn. subsp. pallasiana (Lamb.) Holmboe) of at least 200?years old through an N–S transect covering Bolu-Mengen (north), Kütahya–Simav, and Antalya–Alanya (south) forests. Cellulose was extracted from 5-year blocks of tree rings from lower to upper altitudes in each region. Dendrochronological site chronologies were built for each of the 6 sites, and response to climate was evaluated. The long-term δ¹³C chronologies comprising the period 1800–2008 strongly decline by an average of 2.5‰ from the mid-twentieth century, which corresponds with the commencement of industrialization in Turkey. Oxygen isotope (δ¹⁸O) time series show dominantly low undulations, although some high-frequency variations of up to 6‰ are also observed. As a result of latitude and continent effects, oxygen isotope values of tree rings show an average of 3‰ increase from south (Antalya) to the north (Bolu). Correlations between carbon isotope ratios yield high positive values indicating that industrial pollution exerts a major control on the δ¹³C systematics of the studied trees. Corrected δ¹³C ratios are mostly represented by strong positive responses to variations in temperature and precipitation, whereas δ¹⁸O and summer temperature/precipitation are negatively correlated. Tree-ring widths and δ¹⁸O display similar responses to the temperature and sensitivity to the climatic impact of historic volcanic eruptions, and changes in the solar irradiance record are also detected in other high-resolution paleoclimate archives for the region.     

金沙江干热河谷几种引进树种人工植被的生态学研究

采用标准木法和收获法,对金沙江元谋干热河谷几种引进树种的人工植被（即赤桉×新银合欢混交林、赤桉纯林、新银合欢纯林和印楝纯林）各层植被生物量与天然次生植被（坡柳-扭黄茅灌草丛）进行了比较研究,同时对各类植被的物种组成和物种多样性进行了比较分析。结果表明：（1）采用引进树种人工恢复的植被积累了大量生物质,总生物量大小依次为：赤桉×新银合欢混交林（4491 t/hm2）>新银合欢纯林（3991 t/hm2）>赤桉纯林（3857 t/ hm2）>印楝纯林（1306 t/hm2）>天然次生林（935 t/ hm2）。人工恢复植被生物量主要集中在乔木层,天然次生植被生物量主要集中在灌木、草本和凋落物层。（2）人工恢复植被的物种数均少于天然次生植被,而且不同植被的物种数和物种组成也存在差异。（3）各植被的Shannon wiener多样性指数和Margalef丰富度指数均表现为：印楝纯林>坡柳-扭黄茅灌草丛>赤桉纯林>赤桉×新银合欢混交林。在Alatato均匀度指数方面,各人工植被之间的差异不大,但人工植被与天然次生植被之间有显著差异。〖     

Towards a general relationship between climate change and biodiversity: an example for plant species in Europe

Climate change is one of the main factors that will affect biodiversity in the future and may even cause species extinctions. We suggest a methodology to derive a general relationship between biodiversity change and global warming. In conjunction with other pressure relationships, our relationship can help to assess the combined effect of different pressures to overall biodiversity change and indicate areas that are most at risk. We use a combination of an integrated environmental model (IMAGE) and climate envelope models for European plant species for several climate change scenarios to estimate changes in mean stable area of species and species turnover. We show that if global temperature increases, then both species turnover will increase, and mean stable area of species will decrease in all biomes. The most dramatic changes will occur in Northern Europe, where more than 35% of the species composition in 2100 will be new for that region, and in Southern Europe, where up to 25% of the species now present will have disappeared under the climatic circumstances forecasted for 2100. In Mediterranean scrubland and natural grassland/steppe systems, arctic and tundra systems species turnover is high, indicating major changes in species composition in these ecosystems. The mean stable area of species decreases mostly in Mediterranean scrubland, grassland/steppe systems and warm mixed forests.     

Forest dynamics in Mississippi, USA: a hybrid statistical and geospatial analysis

Understanding forest changes and its trajectory is important to develop policy options and future scenarios for climate analysis. This research is conducted to gain insights on secondary forests change using Mississippi, USA, as a case study. We investigate the spatial patterns and temporal dynamics of secondary forests at high resolution and examine the forces driving their changes. An extensive literature review is conducted to refine the conceptual framework of forest changes and identify the underlying key factors. Forest changes are quantified at high spatial (30-m) and temporal (biennial) resolutions, using time series remotely sensed data between 1984 and 2007. A number of geospatial and socioeconomic data were compiled to analyze the spatial variations of forest disturbances and their linkages to various socioeconomic, political, and biogeophysical factors. The results show that the secondary forests are highly dynamic and variable. Disturbances and regeneration occur continuously everywhere in a systematic and coordinated fashion. This pattern prevents an extensive disturbance and increases total forest cover. Market conditions (i.e., timber price) are the key predictor of the level and overall trend of forest disturbances. However, spatial patterns of forest dynamics cannot be explained by location-specific biophysical, socioeconomic, and policy factors identified in the literature. They can best be described by the ecological characteristics of the forests (i.e., the forest type and age distribution), which have a clear economic linkage. The research shows that regenerated forests frequently experience loss and gain of their extent, and their ecological characteristics change drastically on a short-term basis. These results point out challenges and opportunities in forest management and policy with regard to reforestation.     

The Holocene dynamics of vegetation and climatic conditions on the eastern slope of the Subpolar Urals

Changes in the vegetation and climatic conditions on the eastern slope of the Subpolar Urals over the past 10000 years have been reconstructed on the basis of integrated palynological, botanical, and radiocarbon analysis of material from two sections of peat deposits in the floodplains of the Lyapin and Man’ya rivers (the Severnaya Sos’va basin). The dynamics of regional vegetation have been traced: from the herb–shrub tundra in the late postglacial time to the spruce–larch forest–tundra and sparse larch–birch–spruce stands in the Early Holocene, to birch–pine–spruce forests with an admixture of fir in the Middle Holocene, and to northern taiga forests with dominance of Scots pine and Siberian stone pine (similar to present-day forests) in the Late Holocene. The results show that the northern taiga zone of the study region in the period between approximately 5500 and 2500 years BP was occupied by forests of middle and southern taiga facies, as the climate was significantly warmer than it is today.     

Structural-functional organization of lower vegetation layers in tree communities of the upper timberline ecotone in the Polar Urals

Typologically identical (dwarf birch-herb-dwarf shrub-moss) open and closed larch forests growing on the same altitudinal transect have proved to differ in the structural-functional organization of lower vegetation layers. Coverage, general species composition, and species richness of the herb-dwarf shrub layer are higher in the open forest than in the closed forest. Correlations between individual species of vascular plants weaken upon transition from the open to the closed forest. Conversely, the coverage of the lichen-moss layer increases in the closed forest, which contributes to its role as a factor of selection of vascular plant species against the background of the prevailing influence of the tree layer.     

Impacts of climate change on Chinese ecosystems: key vulnerable regions and potential thresholds

China is a key vulnerable region of climate change in the world. Climate warming and general increase in precipitation with strong temporal and spatial variations have happened in China during the past century. Such changes in climate associated with the human disturbances have influenced natural ecosystems of China, leading to the advanced plant phenology in spring, lengthened growing season of vegetation, modified composition and geographical pattern of vegetation, especially in ecotone and tree-lines, and the increases in vegetation cover, vegetation activity and net primary productivity. Increases in temperature, changes in precipitation regime and CO₂ concentration enrichment will happen in the future in China according to climate model simulations. The projected climate scenarios (associated with land use changes again) will significantly influence Chinese ecosystems, resulting in a northward shift of all forests, disappearance of boreal forest from northeastern China, new tropical forests and woodlands move into the tropics, an eastward shift of grasslands (expansion) and deserts (shrinkage), a reduction in alpine vegetation and an increase in net primary productivity of most vegetation types. Ecosystems in northern and western parts of China are more vulnerable to climate changes than those in eastern China, while ecosystems in the east are more vulnerable to land use changes other than climate changes. Such assessment could be helpful to address the ultimate objective of the United Nations Framework Convention on Climate Change (UNFCCC Article 2).     

The holocene dynamics of vegetation and environmental conditions on the eastern slope of the Northern Urals

Consideration is given to changes in the vegetation and climatic conditions on the eastern slope of the Northern Urals in the second half of the Holocene as reconstructed on the basis of integrated palynological, botanical, paleocarpological, and radiocarbon analysis of material from a peat bog section in the floodplain of the Loz’va River. The results show that the northern taiga zone of the study region in the period between approximately 5000 and 700 years BP was occupied by forests of southern taiga facies, as the climate was significantly warmer than it is today.