Change Scenarios (change + scenario)

Distribution by Scientific Domains
Distribution within Life Sciences

Kinds of Change Scenarios

  • climate change scenario
  • climatic change scenario
  • global change scenario


  • Selected Abstracts


    Performance of High Arctic tundra plants improved during but deteriorated after exposure to a simulated extreme temperature event

    GLOBAL CHANGE BIOLOGY, Issue 12 2005
    Fleur L. Marchand
    Abstract Arctic ecosystems are known to be extremely vulnerable to climate change. As the Intergovernmental Panel on Climate Change scenarios project extreme climate events to increase in frequency and severity, we exposed High Arctic tundra plots during 8 days in summer to a temperature rise of approximately 9°C, induced by infrared irradiation, followed by a recovery period. Increased plant growth rates during the heat wave, increased green cover at the end of the heat wave and higher chlorophyll concentrations of all four predominating species (Salix arctica Pall., Arctagrostis latifolia Griseb., Carex bigelowii Torr. ex Schwein and Polygonum viviparum L.) after the recovery period, indicated stimulation of vegetative growth. Improved plant performance during the heat wave was confirmed at plant level by higher leaf photochemical efficiency (Fv/Fm) and at ecosystem level by increased gross canopy photosynthesis. However, in the aftermath of the temperature extreme, the heated plants were more stressed than the unheated plants, probably because they acclimated to warmer conditions and experienced the return to (low) ambient as stressful. We also calculated the impact of the heat wave on the carbon balance of this tundra ecosystem. Below- and aboveground respiration were stimulated by the instantaneous warmer soil and canopy, respectively, outweighing the increased gross photosynthesis. As a result, during the heat wave, the heated plots were a smaller sink compared with their unheated counterparts, whereas afterwards the balance was not affected. If other High Arctic tundra ecosystems react similarly, more frequent extreme temperature events in a future climate may shift this biome towards a source. It is uncertain, however, whether these short-term effects will hold when C exchange rates acclimate to higher average temperatures. [source]


    Teaching and Learning Guide for: The Geopolitics of Climate Change

    GEOGRAPHY COMPASS (ELECTRONIC), Issue 5 2008
    Jon Barnett
    Author's Introduction Climate change is a security problem in as much as the kinds of environmental changes that may result pose risks to peace and development. However, responsibilities for the causes of climate change, vulnerability to its effects, and capacity to solve the problem, are not equally distributed between countries, classes and cultures. There is no uniformity in the geopolitics of climate change, and this impedes solutions. Author Recommends 1.,Adger, W. N., et al. (eds) (2006). Fairness in adaptation to climate change. Cambridge, MA: MIT Press. A comprehensive collection of articles on the justice dimensions of adaptation to climate change. Chapters discuss potential points at which climate change becomes ,dangerous', the issue of adaptation under the United Nations Framework Convention on Climate Change (UNFCCC), the unequal outcomes of adaptation within a society, the effects of violent conflict on adaptation, the costs of adaptation, and examples from Bangladesh, Tanzania, Botswana, and Hungary. 2.,Leichenko, R., and O'Brien, K. (2008). Environmental change and globalization: double exposures. New York: Oxford University Press. This book uses examples from around the world to show the way global economic and political processes interact with environmental changes to create unequal outcomes within and across societies. A very clear demonstration of the way vulnerability to environmental change is as much driven by social processes as environmental ones, and how solutions lie within the realm of decisions about ,development' and ,environment'. 3.,Nordås, R., and Gleditsch, N. (2007). Climate conflict: common sense or nonsense? Political Geography 26 (6), pp. 627,638. doi:10.1016/j.polgeo.2007.06.003 An up-to-date, systematic and balanced review of research on the links between climate change and violent conflict. See also the other papers in this special issue of Political Geography. 4.,Parry, M., et al. (eds) (2007). Climate change 2007: impacts adaptation and vulnerability. Contribution of Working Group II to the fourth assessment report of the intergovernmental panel on climate change. Cambridge, UK: Cambridge University Press. The definitive review of all the peer-reviewed research on the way climate change may impact on places and sectors across the world. Includes chapters on ecosystems, health, human settlements, primary industries, water resources, and the major regions of the world. All chapters are available online at http://www.ipcc.ch/ipccreports/ar4-wg2.htm 5.,Salehyan, I. (2008). From climate change to conflict? No consensus yet. Journal of Peace Research 45 (3), pp. 315,326. doi:10.1177/0022343308088812 A balanced review of research on the links between climate change and conflict, with attention to existing evidence. 6.,Schwartz, P., and Randall, D. (2003). An abrupt climate change scenario and its implications for United States national security. San Francisco, CA: Global Business Network. Gives insight into how the US security policy community is framing the problem of climate change. This needs to be read critically. Available at http://www.gbn.com/ArticleDisplayServlet.srv?aid=26231 7.,German Advisory Council on Global Change. (2007). World in transition: climate change as a security risk. Berlin, Germany: WBGU. A major report from the German Advisory Council on Global Change on the risks climate changes poses to peace and stability. Needs to be read with caution. Summary and background studies are available online at http://www.wbgu.de/wbgu_jg2007_engl.html 8.,Yamin, F., and Depedge, J. (2004). The International climate change regime: a guide to rules, institutions and procedures. Cambridge, UK: Cambridge University Press. A clear and very detailed explanation of the UNFCCC's objectives, actors, history, and challenges. A must read for anyone seeking to understand the UNFCCC process, written by two scholars with practical experience in negotiations. Online Materials 1.,Environmental Change and Security Program at the Woodrow Wilson International Center for Scholars http://www.wilsoncenter.org/ecsp The major website for information about environmental security. From here, you can download many reports and studies, including the Environmental Change and Security Project Report. 2.,Global Environmental Change and Human Security Project http://www.gechs.org This website is a clearing house for work and events on environmental change and human security. 3.,Intergovernmental Panel on Climate Change (IPCC) http://www.ipcc.ch/ From this website, you can download all the chapters of all the IPCC's reports, including its comprehensive and highly influential assessment reports, the most recent of which was published in 2007. The IPCC were awarded of the Nobel Peace Prize ,for their efforts to build up and disseminate greater knowledge about man-made (sic) climate change, and to lay the foundations for the measures that are needed to counteract such change'. 4.,Tyndall Centre for Climate Change Research http://www.tyndall.ac.uk The website of a major centre for research on climate change, and probably the world's leading centre for social science based analysis of climate change. From this site, you can download many publications about mitigation of and adaptation to climate change, and about various issues in the UNFCCC. 5.,United Nations Framework Convention on Climate Change http://unfccc.int/ The website contains every major document relation to the UNFCCC and its Kyoto Protocol, including the text of the agreements, national communications, country submissions, negotiated outcomes, and background documents about most key issues. Sample Syllabus: The Geopolitics of Climate Change topics for lecture and discussion Week I: Introduction Barnett, J. (2007). The geopolitics of climate change. Geography Compass 1 (6), pp. 1361,1375. United Nations Secretary General, Kofi Annan, address to the 12th Conference of Parties to the United Nations Framework Convention on Climate Change, Nairobi, 15 November 2006. Available online at http://www.unep.org/Documents.Multilingual/Default.asp?DocumentID=495&ArticleID=5424&l=en Week II: The History and Geography of Greenhouse Gas Emissions Topic: The drivers of climate change in space and time Reading Baer, P. (2006). Adaptation: who pays whom? In: Adger, N., et al. (eds) Fairness in adaptation to climate change. Cambridge, MA: MIT Press, pp. 131,154. Boyden, S., and Dovers, S. (1992). Natural-resource consumption and its environmental impacts in the Western World: impacts of increasing per capita consumption. Ambio 21 (1), pp. 63,69. Week III: The Environmental Consequences of climate change Topic: The risks climate change poses to environmental systems Reading Intergovernmental Panel on Climate Change. (2007). Climate change 2007: climate change impacts, adaptation and vulnerability: summary for policymakers. Geneva, Switzerland: IPCC Secretariat. Watch: Al Gore. The Inconvenient Truth. Weeks IV and V: The Social Consequences of Climate Change Topic: The risks climate change poses to social systems Reading Adger, W. N. (1999). Social vulnerability to climate change and extremes in coastal Vietnam. World Development 27, pp. 249,269. Comrie, A. (2007). Climate change and human health. Geography Compass 1 (3), pp. 325,339. Leary, N., et al. (2006). For whom the bell tolls: vulnerability in a changing climate. A Synthesis from the AIACC project, AIACC Working Paper No. 21, International START Secretariat, Florida. Stern, N. (2007). Economics of climate change: the Stern review. Cambridge, UK: Cambridge University Press (Chapters 3,5). Week VI: Mitigation of Climate Change: The UNFCCC Topic: The UNFCCC and the Kyoto Protocol Reading Najam, A., Huq, S., and Sokona, Y. (2003). Climate negotiations beyond Kyoto: developing countries concerns and interests. Climate Policy 3 (3), pp. 221,231. UNFCCC Secretariat. (2005). Caring for climate: a guide to the climate change convention and the Kyoto Protocol. Bonn, Germany: UN Framework Convention on Climate Change Secretariat. Weeks VII and VIII: Adaptation to Climate Change Topic: What can be done to allow societies to adapt to avoid climate impacts? Reading Adger, N., et al. (2007). Assessment of adaptation practices, options, constraints and capacity. In: Parry, M., et al. (eds) Climate change 2007: impacts, adaptation and vulnerability. Contribution of Working Group II to the fourth assessment report of the intergovernmental panel on climate change. Cambridge, UK: Cambridge University Press, pp. 717,744. Burton, I., et al. (2002). From impacts assessment to adaptation priorities: the shaping of adaptation policy. Climate Policy 2 (2,3), pp. 145,159. Eakin, H., and Lemos, M. C. (2006). Adaptation and the state: Latin America and the challenge of capacity-building under globalization. Global Environmental Change: Human and Policy Dimensions 16 (1), pp. 7,18. Ziervogel, G., Bharwani, S., and Downing, T. (2006). Adapting to climate variability: pumpkins, people and policy. Natural Resources Forum 30, pp. 294,305. Weeks IX and X: Climate Change and Migration Topic: Will climate change force migration? Readings Gaim, K. (1997). Environmental causes and impact of refugee movements: a critique of the current debate. Disasters 21 (1), pp. 20,38. McLeman, R., and Smit, B. (2006). Migration as adaptation to climate change. Climatic Change 76 (1), pp. 31,53. Myers, N. (2002). Environmental refugees: a growing phenomenon of the 21st century. Philosophical Transactions of the Royal Society 357 (1420), pp. 609,613. Perch-Nielsen, S., Bättig, M., and Imboden, D. (2008). Exploring the link between climate change and migration. Climatic Change (online first, forthcoming); doi:10.1007/s10584-008-9416-y Weeks XI and XII: Climate Change and Violent Conflict Topic: Will Climate change cause violent conflict? Readings Barnett, J., and Adger, N. (2007). Climate change, human security and violent conflict. Political Geography 26 (6), pp. 639,655. Centre for Strategic and International Studies. (2007). The age of consequences: the foreign policy and national security implications of global climate change. Washington, DC: CSIS. Nordås, R., and Gleditsch, N. (2007). Climate conflict: common sense or nonsense? Political Geography 26 (6), pp. 627,638. Schwartz, P., and Randall, D. (2003). An abrupt climate change scenario and its implications for United States national security. San Francisco, CA: Global Business Network. [online]. Retrieved on 8 April 2007 from http://www.gbn.com/ArticleDisplayServlet.srv?aid=26231 Focus Questions 1Who is most responsible for climate change? 2Who is most vulnerable to climate change? 3Does everyone have equal power in the UNFCCC process? 4Will climate change force people to migrate? Who? 5What is the relationship between adaptation to climate change and violent conflict? [source]


    Genetic maladaptation of coastal Douglas-fir seedlings to future climates

    GLOBAL CHANGE BIOLOGY, Issue 7 2007
    J. BRADLEY ST CLAIR
    Abstract Climates are expected to warm considerably over the next century, resulting in expectations that plant populations will not be adapted to future climates. We estimated the risk of maladaptation of current populations of coastal Douglas-fir (Pseudotsuga menziesii var. menziesii) to future climates as the proportion of nonoverlap between two normal distributions where the means and genetic variances of current and future populations are determined from genecological models derived from seedling common garden studies. The risk of maladaptation was large for most traits when compared with the risk associated with current transfers within seed zones, particularly for the more drastic climate change scenario. For example, the proportion of nonoverlap for a composite trait representing bud set, emergence, growth, and root : shoot ratio was as high as 0.90. We recommend augmenting within-population variation by mixing local populations with some proportion of populations from lower elevations and further south. Populations expected to be adapted to climates a century from now come from locations as far down in elevation as 450,1130 m and as far south in latitude as 1.8,4.9°. [source]


    Consequences of simultaneous elevation of carbon dioxide and temperature for plant,herbivore interactions: a metaanalysis

    GLOBAL CHANGE BIOLOGY, Issue 1 2006
    E. L. ZVEREVA
    Abstract The effects of elevated carbon dioxide on plant,herbivore interactions have been summarized in a number of narrative reviews and metaanalyses, while accompanying elevation of temperature has not received sufficient attention. The goal of our study is to search, by means of metaanalysis, for a general pattern in responses of herbivores, and plant characteristics important for herbivores, to simultaneous experimental increase of carbon dioxide and temperature (ECET) in comparison with both ambient conditions and responses to elevated CO2 (EC) and temperature (ET) applied separately. Our database includes 42 papers describing studies of 31 plant species and seven herbivore species. Nitrogen concentration and C/N ratio in plants decreased under both EC and ECET treatments, whereas ET had no significant effect. Concentrations of nonstructural carbohydrates and phenolics increased in EC, decreased in ET and did not change in ECET treatments, whereas terpenes did not respond to EC but increased in both ET and ECET; leaf toughness increased in both EC and ECET. Responses of defensive secondary compounds to treatments differed between woody and green tissues as well as between gymnosperm and angiosperm plants. Insect herbivore performance was adversely affected by EC, favoured by ET, and not modified by ECET. Our analysis allowed to distinguish three types of relationships between CO2 and temperature elevation: (1) responses to EC do not depend on temperature (nitrogen, C/N, leaf toughness, phenolics in angiosperm leaves), (2) responses to EC are mitigated by ET (sugars and starch, terpenes in needles of gymnosperms, insect performance) and (3) effects emerge only under ECET (nitrogen in gymnosperms, and phenolics and terpenes in woody tissues). This result indicates that conclusions of CO2 elevation studies cannot be directly extrapolated to a more realistic climate change scenario. The predicted negative effects of CO2 elevation on herbivores are likely to be mitigated by temperature increase. [source]


    Potential changes in the distributions of latitudinally restricted Australian butterfly species in response to climate change

    GLOBAL CHANGE BIOLOGY, Issue 10 2002
    Linda J. Beaumont
    Abstract This study assessed potential changes in the distributions of Australian butterfly species in response to global warming. The bioclimatic program, BIOCLIM, was used to determine the current climatic ranges of 77 butterfly species restricted to Australia. We found that the majority of these species had fairly wide climatic ranges in comparison to other taxa, with only 8% of butterfly species having a mean annual temperature range spanning less than 3 °C. The potential changes in the distributions of 24 butterfly species under four climate change scenarios for 2050 were also modelled using BIOCLIM. Results suggested that even species with currently wide climatic ranges may still be vulnerable to climate change; under a very conservative climate change scenario (with a temperature increase of 0.8,1.4 °C by 2050) 88% of species distributions decreased, and 54% of species distributions decreased by at least 20%. Under an extreme scenario (temperature increase of 2.1,3.9 °C by 2050) 92% of species distributions decreased, and 83% of species distributions decreased by at least 50%. Furthermore, the proportion of the current range that was contained within the predicted range decreased from an average of 63% under a very conservative scenario to less than 22% under the most extreme scenario. By assessing the climatic ranges that species are currently exposed to, the extent of potential changes in distributions in response to climate change and details of their life histories, we identified species whose characteristics may make them particularly vulnerable to climate change in the future. [source]


    Stemwood volume increment changes in European forests due to climate change,a simulation study with the EFISCEN model

    GLOBAL CHANGE BIOLOGY, Issue 4 2002
    Gert-Jan Nabuurs
    Abstract This paper presents the results of a modelling study of future net annual increment changes in stemwood of European forests owing to climate change. Seven process-based growth models were applied to 14 representative forest sites across Europe under one climate change scenario. The chosen scenario was the HadCM2 run, based on emission scenario IS92a, and resulted in an increase in mean temperature of 2.5 °C between 1990 and 2050, and an increase in annual precipitation of 5,15%. The information from those runs was incorporated in a transient way in a large-scale forest resource scenario model, EFISCEN (European forest information scenario). European scale forest resource projections were made for 28 countries covering 131.7 million ha of forest under two management scenarios for the period until 2050. The results showed that net annual increments in stemwood of European forests under climate change will further increase with an additional 0.9 m3 ha,1 y,1 in 2030 compared to the ongoing increase under a current climate scenario, i.e. an extra 18% increase. After 2030 the extra increment increase is reduced to 0.79 m3 ha,1 y,1 in 2050. Under climate change, absolute net annual increments will increase from the present 4.95, on average for Europe, to 5.93 m3 ha,1 y,1 in 2025. After 2025, increments in all scenarios start to decline owing to ageing of the forest and the high growing stocks being reached. The results of the present study are surrounded by large uncertainties. These uncertainties are caused by unknown emissions in the future, unknown extent of climate change, uncertainty in process-based models, uncertainty in inventory data, and uncertainty in inventory projection. Although the results are thus not conclusive, climate change may lead to extra felling opportunities in European forests of 87 million m3y,1. Because Europe's forests are intensively managed already, management may adapt to climate change relatively easily. However, this study also indicates that climate change may lead to a faster build-up of growing stocks. That may create a less stable forest resource in terms of risks to storm damage. [source]


    Assessing forest growth across southwestern Oregon under a range of current and future global change scenarios using a process model, 3-PG

    GLOBAL CHANGE BIOLOGY, Issue 1 2001
    N. C. Coops
    Summary With improvements in mapping regional distributions of vegetation using satellite-derived information, there is an increasing interest in the assessment of current limitations on forest growth and in making projections of how productivity may be altered in response to changing climatic conditions and management policies. We utilised a simplified physiologically based process model (3-PG) across a 54 000 km2 mountainous region of southwestern Oregon, USA, to evaluate the degree to which maximum periodic mean annual increment (PAI) of forests could be predicted at a set of 448 forest inventory plots. The survey data were pooled into six broad forest types (coastal rain forest, interior coast range forest, mixed conifer, dry-site Douglas-fir, subalpine forest, and pine forest) and compared to the 3-PG predictions at a spatial resolution of 1 km2. We found good agreement (r2 = 0.84) between mean PAI values of forest productivity for the six forest types with those obtained from field surveys. With confidence at this broader level of integration, we then ran model simulations to evaluate the constraints imposed by (i) soil fertility under current climatic conditions, (ii) the effect of doubling monthly precipitation across the region, and (iii) a widely used climatic change scenario that involves modifications in monthly mean temperatures and precipitation, as well as a doubling in atmospheric CO2 concentrations. These analyses showed that optimum soil fertility would more than double growth, with the greatest response in the subalpine type and the least increase in the coastal rain forests. Doubling the precipitation increased productivity in the pine type (> 50%) with reduced responses elsewhere. The climate change scenario with doubled atmospheric CO2 increased growth by 50% on average across all forest types, primarily as a result of a projected 33% increase in photosynthetic capacity. This modelling exercise indicates that, at a regional scale, a general relationship exists between simulated maximum leaf area index and maximum aboveground growth, supporting the contention that satellite-derived estimates of leaf area index may be good measures of the potential productivity of temperate evergreen forests. [source]


    Modelling the hydrologic effects of dynamic land-use change using a distributed hydrologic model and a spatial land-use allocation model

    HYDROLOGICAL PROCESSES, Issue 18 2010
    Hone-Jay Chu
    Abstract This study develops a novel approach for modelling and examining the impacts of time,space land-use changes on hydrological components. The approach uses an empirical land-use change allocation model (CLUE-s) and a distributed hydrological model (DHSVM) to examine various land-use change scenarios in the Wu-Tu watershed in northern Taiwan. The study also uses a generalized likelihood uncertainty estimation approach to quantify the parameter uncertainty of the distributed hydrological model. The results indicate that various land-use policies,such as no change, dynamic change and simultaneous change,have different levels of impact on simulating the spatial distributions of hydrological components in the watershed study. Peak flow rates under simultaneous and dynamic land-use changes are 5·71% and 2·77%, respectively, greater than the rate under the no land-use change scenario. Using dynamic land-use changes to assess the effect of land-use changes on hydrological components is more practical and feasible than using simultaneous land-use change and no land-use change scenarios. Furthermore, land-use change is a spatial dynamic process that can lead to significant changes in the distributions of ground water and soil moisture. The spatial distributions of land-use changes influence hydrological processes, such as the ground water level of whole areas, particularly in the downstream watershed. Copyright © 2010 John Wiley & Sons, Ltd. [source]


    Modelling runoff from highly glacierized alpine drainage basins in a changing climate

    HYDROLOGICAL PROCESSES, Issue 19 2008
    Matthias Huss
    Abstract The future runoff from three highly glacierized alpine catchments is assessed for the period 2007,2100 using a glacio-hydrological model including the change in glacier coverage. We apply scenarios for the seasonal change in temperature and precipitation derived from regional climate models. Glacier surface mass balance and runoff are calculated in daily time-steps using a distributed temperature-index melt and accumulation model. Model components account for changes in glacier extent and surface elevation, evaporation and runoff routing. The model is calibrated and validated using decadal ice volume changes derived from four digital elevation models (DEMs) between 1962 and 2006, and monthly runoff measured at a gauging station (1979,2006). Annual runoff from the drainage basins shows an initial increase which is due to the release of water from glacial storage. After some decades, depending on catchment characteristics and the applied climate change scenario, runoff stabilizes and then drops below the current level. In all climate projections, the glacier area shrinks dramatically. There is an increase in runoff during spring and early summer, whereas the runoff in July and August decreases significantly. This study highlights the impact of glaciers and their future changes on runoff from high alpine drainage basins. Copyright © 2008 John Wiley & Sons, Ltd. [source]


    Changes of air temperature and precipitation in Poland in the period 1951,2000 and their relationship to atmospheric circulation

    INTERNATIONAL JOURNAL OF CLIMATOLOGY, Issue 3 2004
    Jan Degirmend
    Abstract An analysis of trends of mean monthly temperature and precipitation totals in Poland in the period 1951,2000 was carried out. Areal means of temperature and precipitation were used, averaged for 51 meteorological stations evenly distributed within Poland's borders. Sensitivity of air temperature and precipitation variations towards circulation was assessed. Circulation variations were expressed by sea-level pressure in the 52.5°N, 20°E grid point and geostrophic wind calculated from meridional (45,60°N) and latitudinal (10,30°E) pressure gradients. It was shown that the circulation factor explains up to 77% and 44% of temperature and precipitation variance respectively. Significant upward trends of temperature in March and May were detected. Also, the precipitation total in March was on the increase. The last decade of the 20th century was slightly ,too warm' in comparison with the circulation-induced temperature level, as well as with the temperature change scenario according to HadCM2 GS model. An attempt was made to evaluate the contribution of the frequency of snow cover occurrence to the temperature increase in winter, i.e. the temperature,albedo feedback. Copyright © 2004 Royal Meteorological Society [source]


    Towards a taxonomy of software change

    JOURNAL OF SOFTWARE MAINTENANCE AND EVOLUTION: RESEARCH AND PRACTICE, Issue 5 2005
    Jim Buckley
    Abstract Previous taxonomies of software change have focused on the purpose of the change (i.e., the why) rather than the underlying mechanisms. This paper proposes a taxonomy of software change based on characterizing the mechanisms of change and the factors that influence these mechanisms. The ultimate goal of this taxonomy is to provide a framework that positions concrete tools, formalisms and methods within the domain of software evolution. Such a framework would considerably ease comparison between the various mechanisms of change. It would also allow practitioners to identify and evaluate the relevant tools, methods and formalisms for a particular change scenario. As an initial step towards this taxonomy, the paper presents a framework that can be used to characterize software change support tools and to identify the factors that impact on the use of these tools. The framework is evaluated by applying it to three different change support tools and by comparing these tools based on this analysis. Copyright © 2005 John Wiley & Sons, Ltd. [source]


    CLIMATE CHANGE IMPACTS ON WATER RESOURCES OF THE TSENGWEN CREEK WATERSHED IN TAIWAN,

    JOURNAL OF THE AMERICAN WATER RESOURCES ASSOCIATION, Issue 1 2001
    Ching-pin Tung
    ABSTRACT: This study presents a methodology to evaluate the vulnerability of water resources in the Tsengwen creek watershed, Taiwan. Tsengwen reservoir, located in the Tsengwen creek watershed, is a multipurpose reservoir with a primary function to supply water for the ChiaNan Irrigation District. A simulation procedure was developed to evaluate the impacts of climate change on the water resources system. The simulation procedure includes a streamflow model, a weather generation model, a sequent peak algorithm, and a risk assessment process. Three climate change scenarios were constructed based on the predictions of three General Circulation Models (CCCM, GFDL, and GISS). The impacts of climate change on streamflows were simulated, and, for each climate change scenario, the agricultural water demand was adjusted based on the change of potential evapotranspiration. Simulation results indicated that the climate change may increase the annual and seasonal streamflows in the Tsengwen creek watershed. The increase in streamflows during wet periods may result in serious flooding. In addition, despite the increase in streamflows, the risk of water deficit may still increase from between 4 and 7 percent to between 7 and 13 percent due to higher agricultural water demand. The simulation results suggest that the reservoir capacity may need to be expanded. In response to the climate change, four strategies are suggested: (1) strengthen flood mitigation measures, (2) enhance drought protection strategies, (3) develop new water resources technology, and (4) educate the public. [source]


    Probability distributions, vulnerability and sensitivity in Fagus crenata forests following predicted climate changes in Japan

    JOURNAL OF VEGETATION SCIENCE, Issue 5 2004
    Tetsuya Matsui
    Question: How much is the probability distribution of Fagus crenata forests predicted to change under a climate change scenario by the 2090s, and what are the potential impacts on these forests? What are the main factors inducing such changes? Location: The major islands of Japan. Methods: A predictive distribution model was developed with four climatic factors (summer precipitation, PRS; winter precipitation, PRW; minimum temperature of the coldest month, TMC; and warmth index, WI) and five non-climatic factors (topography, surface geology, soil, slope aspect and inclination). A climate change scenario was applied to the model. Results: Areas with high probability (> 0.5) were predicted to decrease by 91%, retreating from the southwest, shrinking in central regions, and expanding northeastwards beyond their current northern limits. A vulnerability index (the reciprocal of the predicted probability) suggests that Kyushu, Shikoku, the Pacific Ocean side of Honshu and southwest Hokkaido will have high numbers of many vulnerable F. crenata forests. The forests with high negative sensitivity indices (the difference between simulated probabilities of occurrence under current and predicted climates) mainly occur in southwest Hokkaido and the Sea of Japan side of northern Honshu. Conclusion: F. crenata forest distributions may retreat from some islands due to a high WI. The predicted northeastward shift in northern Hokkaido is associated with increased TMC and PRS. High vulnerability and negative sensitivity of the forests in southern Hokkaido are due to increased WI. [source]


    Weather, climate, and farmers: an overview

    METEOROLOGICAL APPLICATIONS, Issue S1 2006
    Roger C. Stone
    Abstract Challenges in linking meteorological and climatological information with a wide range of farming decisions are addressed in this paper. In particular, while a considerable amount of weather and climate information is now available for farmers, some types of information under development or already operational, particularly climate forecasting, formation, may be ill-suited for use by farmers for their decision-making. Case studies show it is particularly important for those key farm decisions that are amenable to weather and climate information to be identified clearly so that weather and climate information can be better tailored to suit farming decisions. A participatory approach provides farmers with ownership of the processes associated with development of weather and climate information and facilitates advances in linking climate and weather information and forecasts to farm decisions. Decision-support systems provide useful output when used with farmer discussion groups. Developing appropriate interdisciplinary systems to connect climate, weather, and agronomic information, especially including forecasting systems, with farm management is needed if uptake of weather and climate information by farmers is to be successful. Provision of output of climate change scenario and trend information to aid long-term strategic farm management decisions needs to be considered, especially in regions where more vulnerable farming zones exist. Copyright © 2006 Royal Meteorological Society [source]


    Inferring the past to predict the future: climate modelling predictions and phylogeography for the freshwater gastropod Radix balthica (Pulmonata, Basommatophora)

    MOLECULAR ECOLOGY, Issue 3 2009
    M. CORDELLIER
    Abstract Understanding the impact of past climatic events on species may facilitate predictions of how species will respond to future climate change. To this end, we sampled populations of the common pond snail Radix balthica over the entire species range (northwestern Europe). Using a recently developed analytical framework that employs ecological niche modelling to obtain hypotheses that are subsequently tested with statistical phylogeography, we inferred the range dynamics of R. balthica over time. A Maxent modelling for present-day conditions was performed to infer the climate envelope for the species, and the modelled niche was used to hindcast climatically suitable range at the last glacial maximum (LGM) c. 21 000 years ago. Ecological niche modelling predicted two suitable areas at the LGM within the present species range. Phylogeographic model selection on a COI mitochondrial DNA data set confirmed that R. balthica most likely spread from these two disjunct refuges after the LGM. The match observed between the potential range of the species at the LGM given its present climatic requirements and the phylogeographically inferred refugial areas was a clear argument in favour of niche conservatism in R. balthica, thus allowing to predict the future range. The subsequent projection of the potential range under a global change scenario predicts a moderate pole-ward shift of the northern range limits, but a dramatic loss of areas currently occupied in France, western Great Britain and southern Germany. [source]


    The geography of climate change: implications for conservation biogeography

    DIVERSITY AND DISTRIBUTIONS, Issue 3 2010
    D. D. Ackerly
    Abstract Aim, Climate change poses significant threats to biodiversity, including impacts on species distributions, abundance and ecological interactions. At a landscape scale, these impacts, and biotic responses such as adaptation and migration, will be mediated by spatial heterogeneity in climate and climate change. We examine several aspects of the geography of climate change and their significance for biodiversity conservation. Location, California and Nevada, USA. Methods, Using current climate surfaces (PRISM) and two scenarios of future climate (A1b, 2070,2099, warmer-drier and warmer-wetter), we mapped disappearing, declining, expanding and novel climates, and the velocity and direction of climate change in California and Nevada. We also examined fine-scale spatial heterogeneity in protected areas of the San Francisco Bay Area in relation to reserve size, topographic complexity and distance from the ocean. Results, Under the two climate change scenarios, current climates across most of California and Nevada will shrink greatly in extent, and the climates of the highest peaks will disappear from this region. Expanding and novel climates are projected for the Central Valley. Current temperature isoclines are projected to move up to 4.9 km year,1 in flatter regions, but substantially slower in mountainous areas because of steep local topoclimate gradients. In the San Francisco Bay Area, climate diversity within currently protected areas increases with reserve size and proximity to the ocean (the latter because of strong coastal climate gradients). However, by 2100 of almost 500 protected areas (>100 ha), only eight of the largest are projected to experience temperatures within their currently observed range. Topoclimate variability will further increase the range of conditions experienced and needs to be incorporated in future analyses. Main Conclusions, Spatial heterogeneity in climate, from mesoclimate to topoclimate scales, represents an important spatial buffer in response to climate change, and merits increased attention in conservation planning. [source]


    Predicting the impact of climate change on Australia's most endangered snake, Hoplocephalus bungaroides

    DIVERSITY AND DISTRIBUTIONS, Issue 1 2010
    Trent D. Penman
    Abstract Aim, To predict how the bioclimatic envelope of the broad-headed snake (BHS) (Hoplocephalus bungaroides) may be redistributed under future climate warming scenarios. Location, South-eastern New South Wales, Australia. Methods, We used 159 independent locations for the species and 35 climatic variables to model the bioclimatic envelope for the BHS using two modelling approaches , Bioclim and Maxent. Predictions were made under current climatic conditions and we also predicted the species distribution under low and high climate change scenarios for 2030 and 2070. Results, Broad-headed snakes currently encompass their entire bioclimatic envelope. Both modelling approaches predict that suitable climate space for BHS will be lost to varying degrees under both climate warming scenarios, and under the worst case, only 14% of known snake populations may persist. Main conclusions, Areas of higher elevation within the current range will be most important for persistence of this species because they will remain relatively moist and cool even under climate change and will match the current climate envelope. Conservation efforts should focus on areas where suitable climate space may persist under climate warming scenarios. Long-term monitoring programs should be established both in these areas and where populations are predicted to become extirpated, so that we can accurately determine changes in the distribution of this species throughout its range. [source]


    Herbivore control of annual grassland composition in current and future environments

    ECOLOGY LETTERS, Issue 1 2006
    Halton A. Peters
    Abstract Selective consumption by herbivores influences the composition and structure of a range of plant communities. Anthropogenically driven global environmental changes, including increased atmospheric carbon dioxide (CO2), warming, increased precipitation, and increased N deposition, directly alter plant physiological properties, which may in turn modify herbivore consumption patterns. In this study, we tested the hypothesis that responses of annual grassland composition to global changes can be predicted exclusively from environmentally induced changes in the consumption patterns of a group of widespread herbivores, the terrestrial gastropods. This was done by: (1) assessing gastropod impacts on grassland composition under ambient conditions; (2) quantifying environmentally induced changes in gastropod feeding behaviour; (3) predicting how grassland composition would respond to global-change manipulations if influenced only by herbivore consumption preferences; and (4) comparing these predictions to observed responses of grassland community composition to simulated global changes. Gastropod herbivores consume nearly half of aboveground production in this system. Global changes induced species-specific changes in plant leaf characteristics, leading gastropods to alter the relative amounts of different plant types consumed. These changes in gastropod feeding preferences consistently explained global-change-induced responses of functional group abundance in an intact annual grassland exposed to simulated future environments. For four of the five global change scenarios, gastropod impacts explained > 50% of the quantitative changes, indicating that herbivore preferences can be a major driver of plant community responses to global changes. [source]


    Effects of temperature and sediment properties on benthic CO2 production in an oligotrophic boreal lake

    FRESHWATER BIOLOGY, Issue 8 2010
    IRINA BERGSTRÖM
    Summary 1. Temperature and many other physical and chemical factors affecting CO2 production in lake sediments vary significantly both seasonally and spatially. The effects of temperature and sediment properties on benthic CO2 production were studied in in situ and in vitro experiments in the boreal oligotrophic Lake Pääjärvi, southern Finland. 2. In in situ experiments, temperature of the water overlying the shallow littoral sediment varied seasonally between 0.5 and 15.7 °C, but in deep water (,20 m) the range was only 1.1,6.6 °C. The same exponential model (r2 = 0.70) described the temperature dependence at 1.2, 10 and 20 m depths. At 2.5 and 5 m depths, however, the slopes of the two regression models (r2 = 0.94) were identical but the intercept values were different. Sediment properties (wet, dry, mineral and organic mass) varied seasonally and with depth, but they did not explain a significantly larger proportion of variation in the CO2 output rate than temperature. 3. In in vitro experiments, there was a clear and uniform exponential dependence of CO2 production on temperature, with a 2.7-fold increase per 10 °C temperature rise. The temperature response (slope of regression) was always the same, but the basic value of CO2 production (intercept) varied, indicating that other factors also contributed to the benthic CO2 output rate. 4. The annual CO2 production of the sediment in Lake Pääjärvi averaged 62 g CO2 m,2, the shallow littoral at 0,3 m depth releasing 114 g CO2 m,2 and deep profundal (>15 m) 30 g CO2 m,2. On the whole lake basis, the shallow littoral at 0,3 m depth accounted for 53% and the sediment area in contact with the summer epilimnion (down to a depth c. 10 m) 75% of the estimated total annual CO2 output of the lake sediment, respectively. Of the annual production, 83% was released during the spring and summer. 5. Using the temperature-CO2 production equations and climate change scenarios we estimated that climatic warming might increase littoral benthic CO2 production in summer by nearly 30% from the period 1961,90 to the period 2071,2100. [source]


    A model for predicting the emergence of dragonflies in a changing climate

    FRESHWATER BIOLOGY, Issue 9 2008
    OTTO RICHTER
    Summary 1. Precise models for the phenology of different species are essential for predicting the potential effects of any temporal mismatch of life cycles with environmental parameters under different climate change scenarios. Here we investigated the effects of ambient water temperature on the onset and synchrony of emergence for a widespread European riverine dragonfly, Gomphus vulgatissimus. 2. Long-term field data on the annual emergence from two rivers in northern Germany, and additional data from a laboratory experiment with different temperature regimes, were used to develop a model that predicted the onset of emergence by using mainly the temperature sum (degree days) as a parameter. 3. Model predictions of the onset of emergence fitted the observations well and could be transferred between localities. This was particularly so when weighting early winter temperature data by using a day length and a temperature-response function, implying potential additional control mechanisms for the onset of emergence. 4. We simulated effects of different winter temperature regimes on the emergence curves in order to predict the effects of climate change. These indicated an acceleration of emergence by 6,7 days per 1 °C temperature increase, which is corroborated by the laboratory data and is in the upper range of data published for other dragonflies. [source]


    Use of tree rings to study the effect of climate change on trembling aspen in Québec

    GLOBAL CHANGE BIOLOGY, Issue 7 2010
    MARIE-PIERRE LAPOINTE-GARANT
    Abstract In this paper, we present a new approach, based on a mixed model procedure, to quantify the tree-ring-based growth-climate relationship of trembling aspen along a latitudinal gradient from 46 to 54 °N in eastern Canada. This approach allows breaking down the growth response into general intersite and local climatic responses, and analyzing variations of absolute ring width as well as interannual variations in tree growth. The final model also integrates nonclimatic variables such as soil characteristics and the occurrence of insect outbreaks into the growth predictions. Tree level random effects on growth were important as intercepts but were nonsignificant for the climatic variables, indicating that a single climate,growth relationship was justified in our case. The response of tree growth to climate showed, however, a strong dependence on the spatial scale at which the analysis was performed. Intersite variations in tree growth were mostly dependent on variations in the thermal heat sum, a variable that showed low interannual and high intersite variation. When variation for a single site was analyzed, other variables showed up to be important while the heat sum was unimportant. Finally, future growth under six different climate change scenarios was simulated in order to study the potential impact of climate change. Results suggest only moderate growth increases in the northern portion of the gradient and a growth decrease in the southern portion under future climatic conditions. [source]


    Impacts of extreme winter warming in the sub-Arctic: growing season responses of dwarf shrub heathland

    GLOBAL CHANGE BIOLOGY, Issue 11 2008
    S. BOKHORST
    Abstract Climate change scenarios predict an increased frequency of extreme climatic events. In Arctic regions, one of the most profound of these are extreme and sudden winter warming events in which temperatures increase rapidly to above freezing, often causing snow melt across whole landscapes and exposure of ecosystems to warm temperatures. Following warming, vegetation and soils no longer insulated below snow are then exposed to rapidly returning extreme cold. Using a new experimental facility established in sub-Arctic dwarf shrub heathland in northern Sweden, we simulated an extreme winter warming event in the field and report findings on growth, phenology and reproduction during the subsequent growing season. A 1-week long extreme winter warming event was simulated in early March using infrared heating lamps run with or without soil warming cables. Both single short events delayed bud development of Vaccinium myrtillus by up to 3 weeks in the following spring (June) and reduced flower production by more than 80%: this also led to a near-complete elimination of berry production in mid-summer. Empetrum hermaphroditum also showed delayed bud development. In contrast, Vaccinium vitis-idaea showed no delay in bud development, but instead appeared to produce a greater number of actively growing vegetative buds within plots warmed by heating lamps only. Again, there was evidence of reduced flowering and berry production in this species. While bud break was delayed, growing season measurements of growth and photosynthesis did not reveal a differential response in the warmed plants for any of the species. These results demonstrate that a single, short, extreme winter warming event can have considerable impact on bud production, phenology and reproductive effort of dominant plant species within sub-Arctic dwarf shrub heathland. Furthermore, large interspecific differences in sensitivity are seen. These findings are of considerable concern, because they suggest that repeated events may potentially impact on the biodiversity and productivity of these systems should these extreme events increase in frequency as a result of global change. Although climate change may lengthen the growing season by earlier spring snow melt, there is a profound danger for these high-latitude ecosystems if extreme, short-lived warming in winter exposes plants to initial warm temperatures, but then extreme cold for the rest of the winter. Work is ongoing to determine the longer term and wider impacts of these events. [source]


    Spatial scale affects bioclimate model projections of climate change impacts on mountain plants

    GLOBAL CHANGE BIOLOGY, Issue 5 2008
    MANDAR R. TRIVEDI
    Abstract Plant species have responded to recent increases in global temperatures by shifting their geographical ranges poleward and to higher altitudes. Bioclimate models project future range contractions of montane species as suitable climate space shifts uphill. The species,climate relationships underlying such models are calibrated using data at either ,macro' scales (coarse resolution, e.g. 50 km × 50 km, and large spatial extent) or ,local' scales (fine resolution, e.g. 50 m × 50 m, and small spatial extent), but the two approaches have not been compared. This study projected macro (European) and local models for vascular plants at a mountain range in Scotland, UK, under low (+1.7 °C) and high (+3.3 °C) climate change scenarios for the 2080s. Depending on scenario, the local models projected that seven or eight out of 10 focal montane species would lose all suitable climate space at the site. However, the European models projected such a loss for only one species. The cause of this divergence was investigated by cross-scale comparisons of estimated temperatures at montane species' warm range edges. The results indicate that European models overestimated species' thermal tolerances because the input coarse resolution climate data were biased against the cold, high-altitude habitats of montane plants. Although tests at other mountain ranges are required, these results indicate that recent large-scale modelling studies may have overestimated montane species' ability to cope with increasing temperatures, thereby underestimating the potential impacts of climate change. Furthermore, the results suggest that montane species persistence in microclimatic refugia might not be as widespread as previously speculated. [source]


    Voltinism flexibility of a riverine dragonfly along thermal gradients

    GLOBAL CHANGE BIOLOGY, Issue 3 2008
    ERIK BRAUNE
    Abstract Potential effects of future warming should be reflected in life history patterns of aquatic organisms observed in warmer climates or in habitats that are different in ambient temperature. In the special case of the dragonfly Gomphus vulgatissimus (L.) (Odonata: Gomphidae) previous research suggests that voltinism decreases from south to north. We analysed data on voltinism from 11 sample sites along a latitudinal gradient from about 44°N to 53°N, comprising small streams to medium-sized rivers. Furthermore, to simulate different conditions and to allow projections for future climate change scenarios, we developed a population dynamic model based on a projection matrix approach. The parameters of the model are dependent on temperature and day length. Our field results indicate a decrease in voltinism along the latitudinal gradient from southern to northern Europe and a corresponding increase of voltinism with higher temperatures. An increase in voltinism with width of the running water implies an effect of varying habitat temperature. Under the impact of global warming, our model predicts an increased development speed, particularly in the northern part of the latitudinal gradient, an extension of the northern range limit and changes in phenology of G. vulgatissimus, leading to an extension of the flight season in certain regions along the gradient. [source]


    Projecting future N2O emissions from agricultural soils in Belgium

    GLOBAL CHANGE BIOLOGY, Issue 1 2007
    CAROLINE ROELANDT
    Abstract This study analyses the spatial and temporal variability of N2O emissions from the agricultural soils of Belgium. Annual N2O emission rates are estimated with two statistical models, MCROPS and MGRASS, which take account of the impact of changes in land use, climate, and nitrogen-fertilization rate. The models are used to simulate the temporal trend of N2O emissions between 1990 and 2050 for a 10, latitude and longitude grid. The results are also aggregated to the regional and national scale to facilitate comparison with other studies and national inventories. Changes in climate and land use are derived from the quantitative scenarios developed by the ATEAM project based on the Intergovernmental Panel on Climate Change-Special Report on Emissions Scenarios (IPCC-SRES) storylines. The average N2O flux for Belgium was estimated to be 8.6 × 106 kg N2O-N yr,1 (STD = 2.1 × 106 kg N2O-N yr,1) for the period 1990,2000. Fluxes estimated for a single year (1996) give a reasonable agreement with published results at the national and regional scales for the same year. The scenario-based simulations of future N2O emissions show the strong influence of land-use change. The scenarios A1FI, B1 and B2 produce similar results between 2001 and 2050 with a national emission rate in 2050 of 11.9 × 106 kg N2O-N yr,1. The A2 scenario, however, is very sensitive to the reduction in agricultural land areas (,14% compared with the 1990 baseline), which results in a reduced emission rate in 2050 of 8.3 × 106 kg N2O-N yr,1. Neither the climatic change scenarios nor the reduction in nitrogen fertilization rate could explain these results leading to the conclusion that N2O emissions from Belgian agricultural soils will be more markedly affected by changes in agricultural land areas. [source]


    Use and misuse of the IUCN Red List Criteria in projecting climate change impacts on biodiversity

    GLOBAL CHANGE BIOLOGY, Issue 11 2006
    H. RESIT AKÇAKAYA
    Abstract Recent attempts at projecting climate change impacts on biodiversity have used the IUCN Red List Criteria to obtain estimates of extinction rates based on projected range shifts. In these studies, the Criteria are often misapplied, potentially introducing substantial bias and uncertainty. These misapplications include arbitrary changes to temporal and spatial scales; confusion of the spatial variables; and assume a linear relationship between abundance and range area. Using the IUCN Red List Criteria to identify which species are threatened by climate change presents special problems and uncertainties, especially for shorter-lived species. Responses of most species to future climate change are not understood well enough to estimate extinction risks based solely on climate change scenarios and projections of shifts and/or reductions in range areas. One way to further such understanding would be to analyze the interactions among habitat shifts, landscape structure and demography for a number of species, using a combination of models. Evaluating the patterns in the results might allow the development of guidelines for assigning species to threat categories, based on a combination of life history parameters, characteristics of the landscapes in which they live, and projected range changes. [source]


    Potential changes in the distributions of latitudinally restricted Australian butterfly species in response to climate change

    GLOBAL CHANGE BIOLOGY, Issue 10 2002
    Linda J. Beaumont
    Abstract This study assessed potential changes in the distributions of Australian butterfly species in response to global warming. The bioclimatic program, BIOCLIM, was used to determine the current climatic ranges of 77 butterfly species restricted to Australia. We found that the majority of these species had fairly wide climatic ranges in comparison to other taxa, with only 8% of butterfly species having a mean annual temperature range spanning less than 3 °C. The potential changes in the distributions of 24 butterfly species under four climate change scenarios for 2050 were also modelled using BIOCLIM. Results suggested that even species with currently wide climatic ranges may still be vulnerable to climate change; under a very conservative climate change scenario (with a temperature increase of 0.8,1.4 °C by 2050) 88% of species distributions decreased, and 54% of species distributions decreased by at least 20%. Under an extreme scenario (temperature increase of 2.1,3.9 °C by 2050) 92% of species distributions decreased, and 83% of species distributions decreased by at least 50%. Furthermore, the proportion of the current range that was contained within the predicted range decreased from an average of 63% under a very conservative scenario to less than 22% under the most extreme scenario. By assessing the climatic ranges that species are currently exposed to, the extent of potential changes in distributions in response to climate change and details of their life histories, we identified species whose characteristics may make them particularly vulnerable to climate change in the future. [source]


    Modelling the interannual variability of net ecosystem CO2 exchange at a subarctic sedge fen

    GLOBAL CHANGE BIOLOGY, Issue 5 2001
    Timothy J. Griffis
    Abstract This paper presents an empirical model of net ecosystem CO2 exchange (NEE) developed for a subarctic fen near Churchill, Manitoba. The model with observed data helps explain the interannual variability in growing season NEE. Five years of tower-flux data are used to test and examine the seasonal behaviour of the model simulations. Processes controlling the observed interannual variability of CO2 exchange at the fen are examined by exploring the sensitivity of the model to changes in air temperature, precipitation and leaf area index. Results indicate that the sensitivity of NEE to changing environmental controls is complex and varies interannually depending on the initial conditions of the wetland. Changes in air temperature and the timing of precipitation events have a strong influence on NEE, which is largely manifest in gross ecosystem photosynthesis (GEP). Climate change scenarios indicate that warmer air temperatures will increase carbon acquisition during wet years but may act to reduce wetland carbon storage in years that experience a large water deficit early in the growing season. Model simulations for this subarctic sedge fen indicate that carbon acquisition is greatest during wet and warm conditions. This suggests therefore that carbon accumulation was greatest at this subarctic fen during its early developmental stages when hydroclimatic conditions were relatively wet and warm at approximately 2500 years before present. [source]


    Elevated carbon dioxide and irrigation effects on water stable aggregates in a Sorghum field: a possible role for arbuscular mycorrhizal fungi

    GLOBAL CHANGE BIOLOGY, Issue 3 2001
    Matthias C. Rillig
    Summary While soil biota and processes are becoming increasingly appreciated as important parameters for consideration in global change studies, the fundamental characteristic of soil structure is a neglected area of research. In a sorghum [Sorghum bicolor (L.) Moench] field experiment in which CO2[supplied using free-air CO2 enrichment (FACE) technology] was crossed factorially with an irrigation treatment, soil aggregate (1,2 mm) water stability increased in response to elevated CO2. Aggregate water stability was increased by 40% and 20% in response to CO2, at ample and limited water supply treatments, respectively. Soil hyphal lengths of arbuscular mycorrhizal fungi (AMF) increased strongly (with a threefold increase in the dry treatment) in response to CO2, and the concentrations of one fraction (easily extractable glomalin, EEG) of the AMF-produced protein glomalin were also increased. Two fractions of glomalin, and AMF hyphal lengths were all positively correlated with soil aggregate water stability. The present results further support the hypothesis that AMF can become important in global change scenarios. Although in this field study a causal relationship between hyphal length, glomalin and aggregate stability cannot be demonstrated, the present data do suggest that AMF could mediate changes in soil structure under elevated CO2. This could be of great importance in agricultural systems threatened by erosional soil loss. [source]


    Assessing forest growth across southwestern Oregon under a range of current and future global change scenarios using a process model, 3-PG

    GLOBAL CHANGE BIOLOGY, Issue 1 2001
    N. C. Coops
    Summary With improvements in mapping regional distributions of vegetation using satellite-derived information, there is an increasing interest in the assessment of current limitations on forest growth and in making projections of how productivity may be altered in response to changing climatic conditions and management policies. We utilised a simplified physiologically based process model (3-PG) across a 54 000 km2 mountainous region of southwestern Oregon, USA, to evaluate the degree to which maximum periodic mean annual increment (PAI) of forests could be predicted at a set of 448 forest inventory plots. The survey data were pooled into six broad forest types (coastal rain forest, interior coast range forest, mixed conifer, dry-site Douglas-fir, subalpine forest, and pine forest) and compared to the 3-PG predictions at a spatial resolution of 1 km2. We found good agreement (r2 = 0.84) between mean PAI values of forest productivity for the six forest types with those obtained from field surveys. With confidence at this broader level of integration, we then ran model simulations to evaluate the constraints imposed by (i) soil fertility under current climatic conditions, (ii) the effect of doubling monthly precipitation across the region, and (iii) a widely used climatic change scenario that involves modifications in monthly mean temperatures and precipitation, as well as a doubling in atmospheric CO2 concentrations. These analyses showed that optimum soil fertility would more than double growth, with the greatest response in the subalpine type and the least increase in the coastal rain forests. Doubling the precipitation increased productivity in the pine type (> 50%) with reduced responses elsewhere. The climate change scenario with doubled atmospheric CO2 increased growth by 50% on average across all forest types, primarily as a result of a projected 33% increase in photosynthetic capacity. This modelling exercise indicates that, at a regional scale, a general relationship exists between simulated maximum leaf area index and maximum aboveground growth, supporting the contention that satellite-derived estimates of leaf area index may be good measures of the potential productivity of temperate evergreen forests. [source]