Shift Of Vegetation Zones Research Articles

Ormosia (Fabaceae: Faboideae) from the Miocene of southeastern China support historical expansion of the tropical genus in East Asia

ABSTRACT The development of the Asian monsoonal climate sparked a latitudinal shift in vegetation zones from the Oligocene to the Miocene. However, little is known about the history of the megathermal floristic response to the geologic events in key regions like subtropical China. Here, a species of Fabaceae, Ormosia cyclocarpa sp. nov., is recognised based on well-preserved fruits from the Miocene of Zhejiang in middle-subtropical China. This species features dehiscent, compressed suborbicular single-seeded pods with an intramarginal vein. Extensive comparisons with extant/fossil fabaceous taxa confidently support the present taxonomic consideration. Considering the extant distribution, diversity centre and regional climate history, the known fossil occurrences in southern China imply that Ormosia extended northwards during the Miocene from probable tropics of origin into subtropical China, where a once broad latitudinal arid zone prevailed throughout much of the Palaeogene. Such a changing phytogeographic pattern across tropical-subtropical China probably resulted from a drastic East Asian climate change around the Oligo-Miocene boundary, and closely coincided with the early-middle Miocene warming. The spreading of Ormosia and other tropical genera (e.g. Dipterocarpus, Shorea, Bauhinia, Dacrycarpus) sharing similar floristic history in subtropical China indicates a palaeotropical and Miocene origin for some clades of the extant East Asian flora.

Soil‐Aggregate‐Associated Organic Carbon Along Vegetation Zones in Tidal Salt Marshes in the Liaohe Delta

In the tidal salt marshes, the spatial variation of soil carbon (C) quality along the vegetation zones is still unclear. Here, a study is conducted in the mudflat, open shrubland, and dense shrubland in the Liaohe Delta, Northeast China, and soil organic C (OC) stock, particulate organic matter C (POMC), and aggregate‐associated OC in the 0–15 and 15–30 cm depths are investigated along these vegetation zones. Among the three vegetation zones, dense shrubland had the greatest soil OC stock, open shrubland had the lowest value, and mudflat had an intermediate value. In each soil depth, dense shrubland generally had higher soil OC and POMC concentrations, and POMC/OC ratio compared to mudflat and open shrubland, respectively. Moreover, dense shrubland had a greater proportion of macro‐aggregates (>0.25 mm in diameter) and OC content in the macro‐aggregates than mudflat and open shrubland, respectively. In addition, the OC content in the soil macro‐aggregates positively correlated with soil POMC concentration. These results suggest that the high spatial variability in soil OC quantity and quality along the vegetation zones should be incorporated to accurately develop regional C budget in coastal wetlands in the Liaohe Delta, and also imply that a shift in vegetation zones induced by sea level rise could potentially cause substantial changes in the quantity and quality of soil OC in the tidal salt marshes.

Rhododendron species richness patterns and impacts of global warming on its distribution in Central Himalayas, Nepal

Global warming and climate change have caused devastating impacts on biological diversity especially in northern latitude and altitude. Evaluation of species richness patterns and range size distribution is crucial for the conservation and management of biological diversity. As Rhododendron species generally grow in the higher latitude and altitude their study on range size distribution may help to predict the future fate of species against presumed global warming in the Himalayas. This study relates the distribution range of Rhododendron species and the potential impacts of global warming and climate change on it. The distribution range varied from 100 to 2600 m along the Himalayan elevation gradient. Generally, species found at the higher elevation have longer range compared to the species found at lower elevation. Among the Rhododendron species found in Nepal Himalayas, R. epapillatum, R. trichocladum and R. virgatum have only 100 m distribution range, which are therefore most vulnerable to the shift in vegetation zones as a result of future projection of temperature rise. Other species having 300 m range of distribution are also vulnerable to different levels of temperature rise as predicted by various sources. These findings can generate hypothesis that species with shorter distribution rage are more vulnerable to climate change which can be tested quantitatively. This in turn will establish a relationship between distribution ranges of species and shift in vegetation zones, and rising temperatures in the Himalayan region due to global warming.Botanica Orientalis – Journal of Plant Science (2015) 9: 12–19

The Application of Geobiocoenological Landscape Typology in The Modelling of Climate Change Implications

Abstract Geobiocoenological landscape typology, which is used in landscape planning in the Czech Republic, includes vegetation zonation of the landscape. Vegetation zones are determined by climatic conditions. Changes in climatic conditions will probably be manifested in the shift of vegetation zones in the landscape. Mathematical geobiocoenological model of vegetation zonation of the landscape is based on the general ecological relationship between the current vegetation zonation and present climatic conditions and the assumption that this general relationship will be maintained in the future. The paper presents the application of the model using the example of the prediction of changes in climatic conditions for the Norway spruce (the first-generation of the model) and grapevine (the second-generation of the model) in the Czech Republic. In the case of the Norway spruce example, the model shows that the predicted changes in climatic conditions will prevent the cultivation of the spruce in the Czech Republic outside its natural range in mountainous areas. The results of the presented model for grapevine show significant enlargement of areas climatically suitable for growing grapes within the studied area.These examples demonstrate the potential for the application of geobiocoenological landscape typology in the modeling of the effects of climate change in the landscape.

Seasonal variation in kangaroo tooth enamel oxygen and carbon isotopes in southern Australia

Serial sampling of tooth enamel growth increments for carbon and oxygen isotopic analyses of Macropus (kangaroo) teeth was performed to assess the potential for reconstructing paleoseasonality. The carbon isotope composition of tooth enamel apatite carbonate reflects the proportional intake of C3 and C4 vegetation. The oxygen isotopic composition of enamel reflects that of ingested and metabolic water. Tooth enamel forms sequentially from the tip of the crown to the base, so dietary and environmental changes during the tooth's formation can be detected. δ13C and δ18O values were determined for a series of enamel samples drilled from the 3rd and 4th molars of kangaroos that were collected along a 900km north–south transect in southern Australia. The serial sampling method did not yield pronounced seasonal isotopic variation patterns in Macropus enamel. The full extent of dietary isotopic variation may be obscured by attenuation of the isotopic signal during enamel mineralisation. Brachydont (low-crowned) Macropus teeth may be less sensitive to seasonal variation in isotopic composition due to time-averaging during mineralisation. However, geographic variations observed suggest that there may be potential for tracking latitudinal shifts in vegetation zones and seasonal environmental patterns in response to climate change.

Paleoanalogues of global warming in the 21st century

On the basis of landscape-climatic reconstructions for warming periods in the past, likely scenarios of future global warming have been developed for various warming levels that might be reached during the current century. The paleoanalogue of global warming by 0.7–1°C is the Holocene climatic optimum (5.5–6 ka B.P.) and that by 1.7–2°C is the last interglacial optimum (about 125 ka B.P.). The complex analysis concerning response of the principal ecosystem components to the expected warming signifies that there will not be any shifts of vegetation zones during the 21st century; reconstruction will touch only the internal structure of vegetable associations and broadening of interzonal ecotones.

Habitat requirements of the pulmonate land snails Trochulus oreinos oreinos and Cylindrus obtusus endemic to the Northern Calcareous Alps, Austria.

The habitat needs and potential threats to Trochulus oreinos oreinos (Wagner 1915) and Cylindrus obtusus (Draparnaud 1805) were assessed by comparing vegetation maps and our own records. We selected four sites from which we had adequate samples and for which exact vegetation maps were available: the mountains Hoch-schwab, Schneealpe, Rax and Schneeberg. Both taxa prefer open dry alpine grassland with diggable soil and/or stones. T. oreinos oreinos is restricted to subalpine and alpine boulder societies and Caricetum firmae. While C. obtusus dwells on several communities of plants, it seems to be bound to unconsolidated stony ground. As both taxa prefer naturally forest-free areas, they are not affected by structural changes of the habitat, such as reforestation caused by the abandonment of grazing and the shift of vegetation zones. But it has to be considered that T. oreinos oreinos and C. obtusus are limited by microclimatic factors, as they prefer cooler habitats. The mountains Schneealpe, Rax and Schneeberg, reaching barely 2000 m in height, are on the climatic limit of the species distribution. Therefore, the investigated taxa are vulnerable to the upward shift of climate zones. T. oreinos oreinos shows striking similarities in its habitat preference to the Swiss endemic T. biconicus, as both taxa prefer the same dry alpine habitats which are quite different to those of other representatives of the genus, which prefer damp habitats.

A comparison of annual and seasonal carbon dioxide effluxes between sub-Arctic Sweden and High-Arctic Svalbard

Recent climate change predictions suggest altered patterns of winter precipitation across the Arctic. It has been suggested that the presence, timing and quantity of snow all affect microbial activity, thus influencing CO2 production in soil. In this study annual and seasonal emissions of CO2 were estimated in High-Arctic Adventdalen, Svalbard, and sub-Arctic Latnjajaure, Sweden, using a new trace gas-based method to track real-time diffusion rates through the snow. Summer measurements from snow-free soils were made using a chamber-based method. Measurements were obtained from different snow regimes in order to evaluate the effect of snow depth on winter CO2 effluxes. Total annual emissions of CO2 from the sub-Arctic site (0.662–1.487 kg CO2 m–2 yr–1) were found to be more than double the emissions from the High-Arctic site (0.369–0.591 kg CO2 m–2 yr–1). There were no significant differences in winter effluxes between snow regimes or vegetation types, indicating that spatial variability in winter soil CO2 effluxes are not directly linked to snow cover thickness or soil temperatures. Total winter emissions (0.004– 0.248 kg CO2 m–2) were found to be in the lower range of those previously described in the literature. Winter emissions varied in their contribution to total annual production between 1 and 18%. Artificial snow drifts shortened the snow-free period by 2 weeks and decreased the annual CO2 emission by up to 20%. This study suggests that future shifts in vegetation zones may increase soil respiration from Arctic tundra regions.

Response of taiga ecosystems to extreme weather conditions and climate anomalies

The resistance of the biosphere to external impacts is the key problem of modern ecology and geography in view of a vague response of modern ecosystems to current and future climate changes and increasing anthropogenic load [5, 10]. Studies of climate changes clarify only possible delayed structural rearrangement of the modern vegetation cover, shift of vegetation zones, and changes in the productivity and reserves of the carbon pool for large regions. Various climate sce� narios are considered, which assume different rates of economic development and changes in the discharge of greenhouse gases to the atmosphere, as well as his� torical analogues of the current and future climate [5]. On the other hand, describing extreme weather phenomena (EWP) and climate anomalies (CAs) in different regions is becoming a topical issue of modern climate studies [4]. The attention of researchers is focused on studying floods, droughts, tornados, and periods of abnormally high summer temperatures— i.e., the phenomena having dramatic adverse conse� quences for the social and economic sphere. Unfortu� nately, the effect of EWP and CA on ecosystems in general is studied very poorly [4]. It should be taken into account that EWP usually are not considered in common climate scenarios and can be hardly pre� dicted by modern climate models. A priori, this means that

Isotope and lignin signatures in tropical peat core (Rawa Danau, Indonesia): An approach to reconstruct past vegetation and climate changes

Peat samples from a 3.60 m core collected from Rawa Danau, West Java, Indonesia, were studied to reconstruct past vegetation and climate changes. The study carried out combining visual observations, elemental analyses, stable carbon and nitrogen isotope analyses as well as CuO oxidation of lignin residues. Variations of total organic carbon (TOC: 55.53-3.18 %, mean 23.31 %), total nitrogen (TN: 2.52-0.06 %, mean 0.94 %) and water content (WC: 46.8-93.2 %, mean 79.0 %) with core lithology reflected dry and wet cycles. Vertical profiles for TOC, TN, WC and core lithology also had signatures of heavy precipitations and consequent land sliding at the abrupt change of climate (wet cycles). Variations of (C/N)a (15-93, mean 27) and δ13C (-27.0 to -30.1 ‰, mean -28.5 ‰) of organic matter (OM) in the peat core indicated that the organic material was comprised of terrestrial C3 plant material. The direct input of aquatic plant matter was small or overwhelmed by high terrestrial input, although changes in lake productivity due to decreasing/increasing nutrient availability were reflected in δ15N profile. At low elevations in the tropical area, a large shift in vegetation zones was not likely observed. Most species might persist at the site when small-scale localized environmental changes and human disturbances or natural forest fires occurred, but the abundances of particular species might change, depending on the natural conditions in which a species could grow. However, vegetation changes associated with periodical sequence of dry and wet microenvironment were inferred from the total lignin phenol (TLP) profile.

Modeling glacial‐interglacial changes in global fire regimes and trace gas emissions

Climate at the Last Glacial Maximum (LGM) together with low atmospheric CO2 concentration forced a shift in vegetation zones, generally favored grasses over woody plants and allowed the colonization of continental shelves. Many studies using models and/or palaeo data have focused on reconstructing climate and vegetation changes between LGM and present, but the implications for changes in fire regime and atmospheric chemistry have not previously been analyzed. We have investigated possible global changes in fire regime using climate model simulations of the LGM to drive the Lund‐Potsdam‐Jena Dynamic Global Vegetation Model (LPJ) with its embedded fire model, Glob‐FIRM. Simulation results reveal a pronounced shift of pyrogenic emission sources to lower latitudes. Global total emissions were slightly reduced. Enhanced nitrogen oxides emissions in the tropics could potentially have increased the oxidizing capacity of the atmosphere, helping to explain the low atmospheric methane concentrations during glacial periods as observed in the ice core records.

Synthesis of Effects in Four Arctic Subregions

An assessment of impacts on Arctic terrestrial ecosystems has emphasized geographical variability in responses of species and ecosystems to environmental change. This variability is usually associated with north-south gradients in climate, biodiversity, vegetation zones, and ecosystem structure and function. It is clear, however, that significant east-west variability in environment, ecosystem structure and function, environmental history, and recent climate variability is also important. Some areas have cooled while others have become warmer. Also, east-west differences between geographical barriers of oceans, archipelagos and mountains have contributed significantly in the past to the ability of species and vegetation zones to relocate in response to climate changes, and they have created the isolation necessary for genetic differentiation of populations and biodiversity hot-spots to occur. These barriers will also affect the ability of species to relocate during projected future warming. To include this east-west variability and also to strike a balance between overgeneralization and overspecialization, the ACIA identified four major sub regions based on large-scale differences in weather and climate-shaping factors. Drawing on information, mostly model output that can be related to the four ACIA subregions, it is evident that geographical barriers to species re-location, particularly the distribution of landmasses and separation by seas, will affect the northwards shift in vegetation zones. The geographical constraints--or facilitation--of northward movement of vegetation zones will affect the future storage and release of carbon, and the exchange of energy and water between biosphere and atmosphere. In addition, differences in the ability of vegetation zones to re-locate will affect the biodiversity associated with each zone while the number of species threatened by climate change varies greatly between subregions with a significant hot-spot in Beringia. Overall, the subregional synthesis demonstrates the difficulty of generalizing projections of responses of ecosystem structure and function, species loss, and biospheric feedbacks to the climate system for the whole Arctic region and implies a need for a far greater understanding of the spatial variability in the responses of terrestrial arctic ecosystems to climate change.

Synthesis of Effects in Four Arctic Subregions

An assessment of impacts on Arctic terrestrial ecosystems has emphasized geographical variability in responses of species and ecosystems to environmental change. This variability is usually associated with north-south gradients in climate, biodiversity, vegetation zones, and ecosystem structure and function. It is clear, however, that significant east-west variability in environment, ecosystem structure and function, environmental history, and recent climate variability is also important. Some areas have cooled while others have become warmer. Also, east-west differences between geographical barriers of oceans, archipelagos and mountains have contributed significantly in the past to the ability of species and vegetation zones to relocate in response to climate changes, and they have created the isolation necessary for genetic differentiation of populations and biodiversity hot-spots to occur. These barriers will also affect the ability of species to relocate during projected future warming. To include this east-west variability and also to strike a balance between overgeneralization and overspecialization, the ACIA identified four major sub regions based on large-scale differences in weather and climate-shaping factors. Drawing on information, mostly model output that can be related to the four ACIA subregions, it is evident that geographical barriers to species re-location, particularly the distribution of landmasses and separation by seas, will affect the northwards shift in vegetation zones. The geographical constraints—or facilitation —of northward movement of vegetation zones will affect the future storage and release of carbon, and the exchange of energy and water between biosphere and atmosphere. In addition, differences in the ability of vegetation zones to re-locate will affect the biodiversity associated with each zone while the number of species threatened by climate change varies greatly between subregions with a significant hot-spot in Beringia. Overall, the subregional synthesis demonstrates the difficulty of generalizing projections of responses of ecosystem structure and function, species loss, and biospheric feedbacks to the climate system for the whole Arctic region and implies a need for a far greater understanding of the spatial variability in the responses of terrestrial arctic ecosystems to climate change.

Arctic terrestrial ecosystems and environmental change

The impacts of environmental change on Arctic terrestrial ecosystems are complex and difficult to predict because of the many interactions which exist within ecosystems and between several concurrently changing environmental variables. However, some general predictions can be made. (i) In the sub-Arctic, subtle shifts in plant community composition with occasional losses of plant species are more likely than immigration of exotic species. In the high Arctic, colonization of bare ground can proceed and there are likely to be shifts in ecotypes. Major shifts in vegetation zones, such as the advance of the boreal forest, are likely to be slow and species specific responses will result in different assemblages of species in plant communities in the longer term. All changes in community structure, apart from species removal by direct extreme weather conditions (e.g. drought) will be slow because of the slow growth, low levels of fecundity and slow migration rates of plant species over large latitudinal ranges. (ii) Mobile mammals and birds can probably adjust to changes in the distribution of their food plants or prey in the Arctic, but vertebrate and invertebrate herbivores may face problems with changes in the quality of their food plants. Non-migratory animals could be severely affected by altered winter snow conditions which affect availability of food and shelter. (iii) Increases in primary production are uncertain and depend mainly upon the responses of soil microbial decomposer activity to changes in soil temperature, moisture and plant litter quality. Assumptions that climate warming will lead to warmer soils and increased nutrient availability to sustain higher productivity are uncertain as greater biomass may lead to reduced soil temperatures through insulation effects and increased nutrients released may be immobilized by soil microorganisms. (iv) Changes in environmental conditions are themselves often uncertain. There is particular doubt about changes in precipitation, growing season length, cloudiness and UV-B radiation levels while such environmental changes are likely to vary in magnitude and direction between different regions of the Arctic. (v) The large populations and circumpolar distributions typical of Arctic biota lead to a strong buffering of changes in biodiversity. Perhaps the greatest threats to Arctic biota will be imposed by the degradation of permafrost which may lead to either waterlogging or drought depending upon precipitation regimes.

Effects of the age class distributions of the temperate and boreal forests on the global CO<sub>2</sub> source-sink function

The role of the temperate and boreal forests as a global CO 2 source or sink is examined, both for the present time and for the next hundred years. The results of the Forest Resource Assessment for 1990 of the Economic Comission for Europe and the Food and Agricultural Organisation of the United Nations (1992) serve as the main database in this study. Out of the estimated total area of approximately 20 • 10 6 km 2 of forests and wooded lands in the temperate and boreal zone only approximately fifty percent is documented within the category of exploitable forests, which are examined in detail here. In this study, a general formalism of the time evolution of an ensemble of forests within an ecological province is developed using the formalism of the Leslie matrix. This matrix can be formulated if the age class dependent mortalities which arise from the disturbances are known. A distinction is made between the natural disturbances by fire, wind throw and insect infestations and disturbances introduced through harvesting of timber. Through the use of Richards growth function each age class of a given biome is related to the corresponding biomass and annual increment. The data reported on the mean net annual increment and on the mean biomass serve to calibrate the model. The difference of the reported net annual increment and annual fellings of approximately 550 • 10 6 m 3 roundwood correspond to a sink of 210-330 Mt of carbon per year excluding any changes in the soil balance. It could be shown that the present distribution of forest age classes for the United States, Canada, Europe, or the former Soviet Union does not correspond to a quasi-stationary state, in which biomass is accumulated only due to a stimulated growth under enhanced atmospheric CO 2 levels. The present CO 2 sink function will not persist in the next century, if harvesting rates increase with 0.5% annually or even less. The future state will also be influenced by the effect of the greenhouse climate, the impact of which may range from a stimulating effect on growth, which is calculated by the Frankfurt biosphere model, up to a transitional negative effect through a shift in vegetation zones. DOI: 10.1034/j.1600-0889.47.issue1.18.x

Vegetation and wildland fire: Implications of global climate change

Abstract Climate, vegetation, and fire are interrelated so that any change in one will affect the others. Increases in greenhouse gases, especially carbon dioxide, are expected to increase average surface temperatures and alter precipitation patterns. These changes will alter numerous biochemical processes of vegetative communities. Changes in growth rates, carbon allocation patterns, nutrient cycling, and competitive interactions will lead to direct changes in the structure and species composition of many plant communities. Major shifts in vegetation zones will occur in many regions. Climate change will affect fire potential by influencing the frequency and severity of weather favorable for fire. Climate-driven changes in the structure and composition of plant communities will also affect fire potential by altering the physical and chemical properties of fuels. Changes in timing and severity of fire will modify the rate at which communities respond to climate change. This in turn will alter fuel properties, further modifying fire potential. Changes in fire regimes will directly affect the chemistry of the atmosphere by modifying vegetation and emitting gases and particulate matter. The expected rate and magnitude of these changes raises questions for the continued integrity, vitality, and stability of current ecosystems.

Effects of Increased Precipitation and Grazing Management on Northeastern Montana Rangelands

Effects of Increased Precipitation and Grazing Management on Northeastern Montana Rangelands

Pollen Stratigraphy of Playa Lakes: ABSTRACT

Since the discovery 15 years ago by Sears and Clisby that the dry lakes (playa lakes) of western North America contain a rich fossil pollen record, Pleistocene specialists have hoped that a definitive chronology would be forthcoming from this largely unglaciated region. Such a chronology should indicate the number of pluvial episodes and the magnitude of each. The deepest drill cores should reveal whether the Pleistocene began with a bang or a whimper. Though hopes for a continuous Pleistocene chronology go largely unrealized, the pollen record of the last glacio-pluvial maximum, the Wisconsin, is increasingly well known. It indicates a major shift in vegetation zones not once but several times during the C-14-datable part of the record. Among the areas studied to date are the San Augustin Plains, the Willcox Playa, Great Salt Lake Desert, and the Texas High Plains. Some control on the fossil pollen record can be gained from the modern pollen rain of natural plant communities in the southwest. Despite formidable problems of long-distance transport of certain pollen types it appears that the major vegetation zones have their own distinctive local pollen pool, End_Page 473------------------------------ making it possible to interpret Pleistocene vegetation history, at least in rough terms. The results are best illustrated in a Pleistocene full-glacial vegetation map. End_of_Article - Last_Page 474------------