Climate Change and Species/Ecosystems

Regional and Country studies

Africa

Malawi

Mkanda, Francis X. 1999. "Drought as an analogue climate change scenario for prediction of potential impacts on Malawi's wildlife habitats," Climate Research, Vol. 12, No 2-3, pp. 215-222.
ABSTRACT: This study compares precipitation and temperature from recent drought episodes with general circulation model outputs to examine the likely effects of climate change on herbaceous layer productivity, ground cover, and forage utilization in Malawi's Lengwe National Park. There are no differences in precipitation distribution and temperature during the drought episodes and climate change scenarios. The implication is that deteriorating habitat conditions such as those observed during the drought incidents might occur under climate change. Herbacious layer productivity was 2 to 6 times lower than in a normal year; ground cover was reduced to 22-32%; and the number of intensely browsed plants increased significantly (chi-square = 10.5, p = 0.01) as the drought progressed. Consequently, it is unlikely that the degraded habitat would support large mammal populations in Lengwe specifically, or in Malawi in general.

Asia

China

Chen, Xiongwen, "Modeling the Effects of Global Climatic Change at the Ecotone of Boreal Larch Forest and Temperate Forest in Northeast China," Climatic Change, Vol. 55, No. 1-2, October, pp. 77-97.
ABSTRACT: The dynamics of the forest at the ecotone of the boreal forest and temperate forest in Northeast China were simulated using the adapted gap model BKPF under global climatic change (GFDL scenario) and doubled CO2 concentrations at 50 years in the future. The response of tree species and species with similar biological characteristics under global climate change and double CO2 concentrations were based on biophysical limits of the tree species in the area and their biological competition. The results showed that after 50 years the stand density and LAI (leaf area index) of the forest growing from a clear-cut would not be significantly different from those under current conditions. Stand productivity would increase about 7%, and stand aboveground biomass would increase 15%. However, the stand density of the current mature forest would be reduced by more than 20%. The stand would be dominated by Quercus mongolica Fisch., Populus davidiana Dode., Betula spp. and other broadleaved tree species, and Quercus mongolica would account for about 50% of the total density. The stand biomass would be reduced by more than 90%. Quercus mongolica would comprise about 57% of the total stand biomass. The stand productivity would not change significantly, but it would be comprised mainly of Quercus mongolica, Populus davidiana, Betula spp. The current stand height would decrease slightly. The stand LAI would decline dramatically, moreover, Quercus mongolica would comprise about 50% of the stand LAI.

Gao, Qiong, Mei Yu, and Xiusheng Yang. 2000. "An Analysis of Sensitivity of Terrestrial Ecosystems in China to Climatic Change Using Spatial Simulation," Climatic Change, Vol. 47, No. 4, December, pp. 373-400. ABSTRACT: A computer simulation model of regional vegetation dynamics was applied to the terrestrial ecosystems of China to study the responses of vegetation to elevated CO2 and global climatic change. The primary production processes were coupled with vegetation structure in the model. The model was parameterized and partially validated in light of a large number of field observations made throughout China on primary productivity, 10 years of monthly meteorological data, 5 years of monthly normalized differential vegetation index observed by NOAA-11 satellite, and digital vegetation and terrain maps. Eight different climatic scenarios, set by perturbations from the present climate, 100% in atmospheric CO2 concentration, 2 °C in monthly mean temperature, and 20% in monthly precipitation, were applied to analyze the sensitivity of the Chinese terrestrial ecosystems to climatic change. Simulation results were obtained for each of the climatic scenarios with the model running toward equilibrium solutions at a time step of 1 month. Preliminary validation indicated that the model was capable of simulating the net primary productivity of most vegetation classes and the potential vegetation structure in China under present climatic conditions. The simulations for the altered climatic scenarios predicted that grasslands, shrubs, and conifer forests are more sensitive to environmental changes than evergreen broadleaf forests in warm, wet southeast China and desert vegetation in cold, arid northwest China. For less than 150% of changes in vegetation structure under altered climatic conditions, about three quarters of the changes in net primary productivity of individual vegetation classes were shown to be attributed to the changes in the corresponding distribution area.

Pakistan

Siddiqui, K. M., Iqbal Mohammad, and Mohammad Ayaz. 1999. "Forest ecosystem climate change impact assessment and adaptation strategies for Pakistan," Climate Research, Vol. 12, No. 2-3, pp. 195-203.
ABSTRACT: A study was carried out to determine the impact of climate change on natural forest ecosystems in Pakistan assuming a 0.3°C rise in temperature and a precipitation change of 0, +1 and -1% decade-1 with 1990 as the base year. The current atmospheric CO2 concentration of 350 ppmv was assumed to increase to 425 ppmv in 2020, 500 ppmv in 2050 and 575 ppmv in 2080. The BIOME3 model was used for computer simulation of 9 dominant plant types, or biomes. Of these, 3 biomes (alpine tundra, grassland/arid woodlands and deserts) showed a reduction in their area, and 5 biomes (cold conifer/mixed woodland, cold conifer/mixed forests, temperate conifer/mixed forests, warm conifer/mixed forests, and steppe/arid shrub lands) showed an increase in their area as a result of climate change. Enhanced CO2 concentration in the atmosphere appeared to have a pronounced effect on the biomes' area. Net primary productivity exhibited an increase in all biomes and scenarios. However, there is a possibility of forest dieback occurring and of time lag before the dominant plant types have enough time to adjust to changed climate and migrate to new sites. In the intervening period, they would be vulnerable to environmental and socio-economic disturbances (e.g. erosion, deforestation, and land-use changes). Thus, the overall impact of climate change on the forest ecosystems of Pakistan could be negative. A number of adaptation strategies are proposed to cope with climate change impacts on forest ecosystems.

India

Ravindranath, N.H., and R. Sukumar. 1998. "Climate Change and Tropical Forests in India," Climatic Change, Vol. 39, No. 2-3, July, pp. 563-581.
ABSTRACT: India has 64 Mha under forests, of which 72% are tropical moist deciduous, dry deciduous, and wet evergreen forest. Projected changes in temperature, rainfall, and soil moisture are considered at regional level for India under two scenarios, the first involving greenhouse gas forcing, and the second, sulphate aerosols. Under the former model, a general increase in temperature and rainfall in all regions is indicated. This could potentially result in increased productivity, and shift forest type boundaries along attitudinal and rainfall gradients, with species migrating from lower to higher elevations and the drier forest types being transformed to moister types. The aerosol model, however, indicates a more modest increase in temperature and a decrease in precipitation in central and northern India, which would considerably stress the forests in these regions.
Although India seems to have stabilized the area under forest since 1980, anthropogenic stresses such as livestock pressure, biomass demand for fuelwood and timber, and the fragmented nature of forests will all affect forest response to changing climate. Thus, forest area is unlikely to expand even if climatically suitable, and will probably decrease in parts of northeast India due to extensive shifting cultivation and deforestation. A number of general adaptation measures to climate change are listed.

Europe

Sukopp, Herbert and Angelika Wurzel. 2003. "The Effects of Climate Change on the Vegetation of Central European Cities," Urban Habitats, Vol. 1, No. 1, pp. 3-26.
PDF: http://www.urbanhabitats.org/v01n01/climatechange_pdf.pdf
ABSTRACT: Since the 1850s the effects of global warming have been anticipated by the rise of temperature in many big cities. In addition, vegetation changes in central European cities have been well documented. This paper explores the changing urban distribution of some ruderal herbaceous species and discusses changes in distribution and physiological changes in tree and shrub species in response to this rise in temperature. Examples of affected species covered here include Acer negundo, Ailanthus altissima, Amelanchier spicata, Berberis julianae, Buddleia davidii, Colutea arborescens, Cornus alba, C. stolonifera, Cotoneaster bullatus, Cytisus multiflorus, C. striatus, Juglans regia, Laburnum anagyroides, Ligustrum vulgare, Mahonia aquifolium, Paulownia tomentosa, Philadelphus coronarius, Platanus ??hispanica, Populus ??canadensis, Prunus armeniaca, P. laurocerasus, P. mahaleb, P. persica, P. serotina, Pyrus communis, Quercus cerris, Q. rubra, Q. robur, Ribes aureum, Robinia pseudacacia, Sambucus spp., Sorbus intermedia agg., Symphoricarpos albus, and Syringa vulgaris. The responses of some woody scramblers and creepers are also examined. For many of these species, there was a long lag time between introduction and invasion in the wild. We briefly review phenological investigations, including studies of Aesculus hippocastanum and Tilia euchlora. Finally, we consider the extent to which cities can act as simulators of global climate change. We conclude that although other ecological and socioeconomic factors are affecting the vegetation in urban areas, many of the nonnative invasive species found colonizing cities (or naturalizing within them) originate in warmer areas and are benefiting from the more favorable climate.

Theurillat, Jean-Paul and Antoine Guisan. 2001. "Potential Impact of Climate Change on Vegetation in the European Alps: A Review," Climatic Change, Vol. 50, No. 1-2, July, pp. 77-109.
ABSTRACT: Based on conclusions drawn from general climatic impact assessment in mountain regions, the review synthesizes results relevant to the European Alps published mainly from 1994 onward in the fields of population genetics, ecophysiology, phenology, phytogeography, modeling, paleoecology and vegetation dynamics. Other important factors of global change interacting synergistically with climatic factors are also mentioned, such as atmospheric CO2 concentration, eutrophication, ozone or changes in land-use. Topics addressed are general species distribution and populations (persistence, acclimation, genetic variability, dispersal, fragmentation, plant/animal interaction, species richness, conservation), potential response of vegetation (ecotonal shift - area, physiography - changes in the composition, structural changes), phenology, growth and productivity, and landscape. In conclusion, the European Alps appear to have a natural inertia and thus to tolerate an increase of 1-2 K of mean air temperature as far as plant species and ecosystems are concerned in general. However, the impact of land-use is very likely to negate this buffer in many areas. For a change of the order of 3 K or more, profound changes may be expected.

Estonia

Nilson, Artur, Andres Kiviste, Henn Korjus, Saadi Mihkelson, Ivar Etverk, and Tõnu Oja. 1999. "Impact of recent and future climate change on Estonian forestry and adaptation tools," Climate Research, Vol. 12, No. 2-3, pp. 205-214.
ABSTRACT: The possible impact of recent and predicted future climate change on forestry in Estonia was studied. The quickening forest growth, about 15% in the last 4 decades, was verified by statistical analysis of the growth of over 50000 stands, and quickening forest growth was predicted for the next century by the RipFor model. The risk of forest damage and the uncertainty of forest growth predictions have been increasing and will continue to do so. The genome diversity of the dominant tree species growing in Estonia is sufficient for adaptation to the changing climate conditions. Computer-aided decision support systems built into the forest management information system can improve forest management planning.

Finland

Heli Peltola, Seppo Kellomäki, and Hannu Väisänen. 1999. "Model Computations of the Impact of Climatic Change on the Windthrow Risk of Trees," Climatic Change, Vol. 41, No. 1, January, pp. 17-36. ABSTRACT: The more humid, warmer weather pattern predicted for the future is expected to increase the windthrow risk of trees through reduced tree anchorage due to a decrease in soil freezing between late autumn and early spring, i.e during the most windy months of the year. In this context, the present study aimed at calculating how a potential increase of up to 4°C in mean annual temperature might modify the duration of soil frost and the depth of frozen soil in forests and consequently increase the risk of windthrow. The risk was evaluated by combining the simulated critical windspeeds needed to uproot Scots pines (Pinus sylvestris L.) under unfrozen soil conditions with the possible change in the frequency of these winds during the unfrozen period. The evaluation of the impacts of elevated temperature on the frequency of these winds at times of unfrozen and frozen soil conditions was based on monthly wind speed statistics for the years 1961-1990 (Meteorological Yearbooks of Finland, 1961-1990). Frost simulations in a Scots pine stand growing on a moraine sandy soil (height 20 m, stand density 800 stems ha-1) showed that the duration of soil frost will decrease from 4-5 months to 2-3 months per year in southern Finland and from 5-6 months to 4-5 months in northern Finland given a temperature elevation of 4°C. In addition, it could decrease substantially more in the deeper soil layers (40-60 cm) than near the surface (0-20 cm), particularly in southern Finland. Consequently, tree anchorage may lose much of the additional support gained at present from the frozen soil in winter, making Scots pines more liable to windthrow during winter and spring storms. Critical wind-speed simulations showed mean winds of 11-15 m s-1 to be enough to uproot Scots pines under unfrozen soil conditions, i.e. especially slender trees with a high height to breast height diameter ratio (taper of 1:120 and 1:100). In the future, as many as 80% of these mean winds of 11-15 m s-1 would occur during months when the soil is unfrozen in southern Finland, whereas the corresponding proportion at present is about 55%. In northern Finland, the percentage is 40% today and is expected to be 50% in the future. Thus, as the strongest winds usually occur between late autumn and early spring, climate change could increase the loss of standing timber through windthrow, especially in southern Finland.

Russia

Krankina, O. N., R. K. Dixon, A. P. Kirilenko, K. I. Kobak. 1997. "Global Climate Change Adaptation: Examples from Russian Boreal Forest," Climatic Change, Vol. 36, No. 1-2, May - June, pp. 197-215.
ABSTRACT: The Russian Federation contains approximately 20% of the world's timber resources and more than half of all boreal forests. These forests play a prominent role in environmental protection and economic development at global, national, and local levels, as well as, provide commodities for indigenous people and habitat for a variety of plant and animal species. The response and feedbacks of Russian boreal forests to projected global climate change are expected to be profound. Large shifts in the distribution (up to 19% area reduction) and productivity of boreal forests are implied by scenarios of General Circulation Models (GCMs). Uncertainty regarding the potential distribution and productivity of future boreal forests complicates the development of adaptation strategies for forest establishment, management, harvesting and wood processing. Although a low potential exists for rapid natural adaptation of long-lived, complex boreal forests, recent analyses suggest Russian forest management and utilization strategies should be field tested to assess their potential to assist boreal forests in adaptation to a changing global environment. Current understanding of the vulnerability of Russian forest resources to projected climate change is discussed and examples of possible adaptation measures for Russian forests are presented, including: (1) artificial forestation techniques that can be applied with the advent of failed natural regeneration and to facilitate forest migration northward; (2) silvicultural measures that can influence the species mix to maintain productivity under future climates; (3) identifying forests at risk and developing special management adaptation measures for them; (4) alternative processing and uses of wood and non-wood products from future forests; and (5) potential future infrastructure and transport systems that can be employed as boreal forests shift northward into melting permafrost zones. Current infrastructure and technology can be employed to help Russian boreal forests adapt to projected global environmental change, however many current forest management practices may have to be modified. Application of this technical knowledge can help policymakers identify priorities for climate change adaptation.

Lelyakin, Alexander L., Alexey O. Kokorin and Igor M. Nazarov. 1997. "Vulnerability of Russian Forests to Climate Changes: Model Estimation of CO2 Fluxes," Climatic Change, Vol. 36, No. 1-2, May - June, pp. 123-133.
ABSTRACT: The aim of this paper is an estimation of the CO2 sequestration by Russian forests, caused by previous and future climate changes. The method of estimation is simulation of carbon budget via mathematical model. This model has a number of specific features: description of age distribution of forests, number of carbon reservoirs, modeling of cuttings and fires. Current net-sink of CO2 is estimated as 160 MtC/yr. This sink will grow up to 200-240 Mt/yr in 2010. Main uncertainty of results are caused by variation in parameters of forest reaction to climate changes.

Latin America

Mexico

Villers-Ruíza, Lourdes, and Irma Trejo-Vázquez. 1998. "Climate change on Mexican forests and natural protected areas," Global Environmental Change, Vol. 8, No. 2, July, pp. 141-157.
ABSTRACT: In order to determine the vulnerability of Mexican forest ecosystems, natural protected and forestry areas to climate change, an assessment was performed under two climate change scenarios generated by the Canadian Climate Center (CCC) and the Geophysical Fluid Dynamics Laboratory (GFDL) models. Based on Holdridge's life zones and local classifications, the results suggest that the most vulnerable life zones would be temperate cold and warm forests, mainly due to the increase in temperature. Tropical dry, very dry and thorn forests would enlarge their current area coverage under the climate change CCC scenario, while under the GFDL scenario increases in the distribution of tropical humid and wet forests would occur. For some ecosystems, such as tropical forest, climate change is a minor threat compared to the degradation currently induced by human activities. A current land-use assessment indicates that, in the recent years, the ecosystems most affected by human activities are the tropical forests due to the expansion of grasslands for tropical cattle ranching. Man-induced forest fires, to increase pasture production, are the main cause of degradation in temperate forests. The natural protected areas most affected by climate change would be the northern and western regions of the country, as well as the southern tropical mountains where an important number of endemic plants exist. On the other hand, forestry areas that would be most affected are located in the Sierra Madre Occidental, where timber exploitation in coniferous forests is high.

Villers-Ruiz, Lourdes, and Irma Trejo-Vázquez. 1997. "Assessment of the vulnerability of forest ecosystems to climate change in Mexico," Climate Research, Vol. 9, No. 1-2, December 29, pp. 87-93.
ABSTRACT: An assessment of the vulnerability of forest ecosystems in Mexico to climate change is carried out on the basis of the scenarios projected by 3 climate models. A vegetation classification was performed according to 2 models, the Holdridge Life Zone Classification and the so-called Mexican Classification (a climate-vegetation classification based on typologies developed for Mexico). Projections of climate models were based on a doubled CO2 concentration condition. The models used were: the CCCM, which estimates an average increase in temperature for the country of 2.8°C and a decrease in annual precipitation of 7%; the GFDL-R30, which estimates an increase in both parameters by 3.2°C and 20% respectively; and a sensitivity model in which a homogeneous increase of 2°C in temperature and a 10% decrease in precipitation are applied throughout the country. In general, the cool temperate and warm temperate ecosystems were the most affected and tended to disappear under the conditions of the 3 scenarios. In contrast, the dry and very dry tropical forests and the warm thorn woodlands tended to occupy larger areas than at present, particularly under the conditions projected by the CCCM model. However, under the GFDL-derived scenario an increase in the distribution of moist and wet forests, which would be favoured by an increase in precipitation, was predicted.

Panama

Condit, Richard. 1998. "Ecological Implications of Changes in Drought Patterns: Shifts in Forest Composition in Panama," Climatic Change, Vol. 39, No. 2-3, July, pp. 413-427.
ABSTRACT: CO2 concentration is increasing, temperature is likely to rise, and precipitation patterns might change. Of these potential climatic shifts, it is precipitation that will have the most impact on tropical forests, and seasonal patterns of rainfall and drought will probably be more important than the total quantity of precipitation. Many tree species are limited in distribution by their inability to survive drought. In a 50 ha forest plot at Barro Colorado Island in Panama (BCI), nearly all tree and shrub species associated with moist microhabitats are declining in abundance due to a decline in rainfall and lengthening dry seasons. This information forms the basis for a simple, general prediction: drying trends can rapidly remove drought-sensitive species from a forest. If the drying trend continues at BCI, the invasion of drought-tolerant species would be anticipated, but computer models predict that it could take 500 or more years for tree species to invade and become established. Predicting climate-induced changes in tropical forest also requires geographic information on tree distribution relative to precipitation patterns. In central Panama, species with the most restricted ranges are those from areas with a short dry season (10-14 weeks): 26-39% of the tree species in these wet regions do not occur where it is drier. In comparison, just 11-19% of species from the drier side of Panama (18 week dry season) are restricted to the dry region. From this information, I predict that a four-week extension of the dry season could eliminate 25% of the species locally; a nine-week extension in very wet regions could cause 40% extinction. Since drier forests are more deciduous than wetter forests, satellite images that monitor deciduousness might provide a way to assess long-term forest changes caused by changes in drought patterns. I predict that increasing rainfall and shorter dry seasons would not cause major extinction in tropical forest, but that drying trends are a much greater concern. Longer dry seasons may cause considerable local extinction of tree species and rapid forest change, and they will also tend to exacerbate direct human damage, which tends to favor drought-adapted and invasive tree species in favor of moisture-demanding ones.

North America

Mortsch, Linda D. 1998. "Assessing the Impact of Climate Change on the Great Lakes Shoreline Wetlands," Climatic Change, Vol. 40, No. 2, October, pp. 391-416.
ABSTRACT: Great Lakes shoreline wetlands are adapted to a variable water supply. They require the disturbance of water level fluctuations to maintain their productivity. However, the magnitude and rate of climate change could alter the hydrology of the Great Lakes and affect wetland ecosystems. Wetlands would have to adjust to a new pattern of water level fluctuations; the timing, duration, and range of these fluctuations are critical to the wetland ecosystem response. Two "what if" scenarios: (1) an increased frequency and duration of low water levels and (2) a changed temporal distribution and amplitude of seasonal water levels were developed to assess the sensitivity of shoreline wetlands to climate change. Wetland functions and values such as wildlife, waterfowl and fish habitat, water quality, areal extent, and vegetation diversity are affected by these scenarios. Key wetlands are at risk, particularly those that are impeded from adapting to the new water level conditions by man-made structures or geomorphic conditions. Wetland remediation, protection and enhancement policies and programs must consider climate change as an additional stressor of wetlands.

Canada

Sorenson, Lisa G., Richard Goldberg, Terry L. Root, and Michael G. Anderson. 1998. "Potential Effects of Global Warming on Waterfowl Populations Breeding in the Northern Great Plains," Climatic Change, Vol. 40, No. 2, October, pp. 343-369.
ABSTRACT: The Prairie Pothole Region (PPR) of the Northern Great Plains is the most important breeding area for waterfowl in North America. Historically, the size of breeding duck populations in the PPR has been highly correlated with spring wetland conditions. We show that one indicator of climate conditions, the Palmer Drought Severity Index (PDSI), is strongly correlated with annual counts (from 1955 to 1996) of both May ponds (R2 = 0.72, p < 0.0001) and breeding duck populations (R2 = 0.69, p < 0.0001) in the Northcentral U.S., suggesting the utility of PDSI as an index for climatic factors important to wetlands and ducks. We then use this relationship to project future pond and duck numbers based on PDSI values generated from sensitivity analyses and two general circulation model (GCM) scenarios. We investigate the sensitivity of PDSI to fixed changes in temperature of 0°C, +1.5°C, +2.5°C, and +4.0°C in combination with fixed changes in precipitation of -10%, +0%, +7%, and +15%, changes spanning the range of typically-projected values for this region from human-induced climatic change. Most (11 of 12) increased temperature scenarios tested result in increased drought (due to greater evapotranspiration under warmer temperatures) and declining numbers of both wetlands and ducks. Assuming a doubling of CO2 by 2060, both the equilibrium and transient GCM scenarios we use suggest a major increase in drought conditions. Under these scenarios, Northcentral U.S. breeding duck populations would fluctuate around means of 2.1 or 2.7 million ducks based on the two GCMs, respectively, instead of the present long-term mean of 5.0 million. May pond numbers would fluctuate around means of 0.6 or 0.8 million ponds instead of the present mean of 1.3 million. The results suggest that the ecologically and economically important PPR could be significantly damaged by climate changes typically projected. We make several recommendations for policy and research to help mitigate potential effects.

United States

Mohseni, Omid, Heinz G. Stefan, and John G. Eaton. 2003. "Global Warming and Potential Changes in Fish Habitat in U.S. Streams," Climatic Change, Vol. 59, No 3, August, pp. 389-409.
ABSTRACT: To project potential habitat changes of 57 fish species under global warming, their suitable thermal habitat at 764 stream gaging stations in the contiguous United States was studied. Global warming was specified by air temperature increases projected by the Canadian Centre of Climate Modelling General Circulation Model for a doubling of atmospheric CO2. The aquatic thermal regime at each gaging station was related to air temperature using a nonlinear stream temperature/air temperature relationship. Suitable fish thermal habitat was assumed to be constrained by both maximum temperature and minimum temperature tolerances. For cold water fishes with a 0 °C lower temperature constraint, the number of stations with suitable thermal habitat under a 2×CO2 climate scenario is projected to decrease by 36%, and for cool water fishes by 15%. These changes are associated with a northward shift of the range. For warm water fishes with a 2 °C lower temperature constraint, the potential number of stations with suitable thermal habitat is projected to increase by 31%.

Wang, Guiming, N. Thompson Hobbs, Francis J. Singer, et al. 2001. "Impacts of Climate Changes on Elk Population Dynamics in Rocky Mountain National Park, Colorado, U.S.A.," Climatic Change, Vol. 54, No. 1-2, July, pp. 205-223.
ABSTRACT: Changing climate may impact wildlife populations in national parks and conservation areas. We used logistic and non-linear matrix population models and 35 years of historic weather and population data to investigate the effects of climate on the population dynamics of elk in Rocky Mountain National Park (RMNP), Colorado, U.S.A. We then used climate scenarios derived from Hadley and Canadian Climate Center (CCC) global climate models to project the potential impact of future climate on the elk population. All models revealed density-dependent effects of population size on growth rates. The best approximating logistic population model suggested that high levels of summer precipitation accelerated elk population growth, but higher summer minimum temperatures slowed growth. The best approximating non-linear matrix model indicated that high mean winter minimum temperatures enhanced recruitment of juveniles, while high summer precipitation enhanced the survival of calves. Warmer winters and wetter summers predicted by the Hadley Model could increase the equilibrium population size of elk by about 100%. Warmer winters and drier summers predicted by the CCC Model could raise the equilibrium population size of elk by about 50%. Managers of national parks have relied on effects of weather, particularly severe winters, to regulate populations of native ungulates and prevent harmful effects of overabundance. Our results suggest that these regulating effects of severe winter weather may weaken if climate changes occur as those that are widely predicted in most climate change scenarios.

Fang, Xing, and Heinz G. Stefan. 1999. "Projections of Climate Change Effects on Water Temperature Characteristics of Small Lakes in the Contiguous U.S.," Climatic Change, Vol. 42, No. 2, June, pp. 377-412.
ABSTRACT: To simulate effects of projected climate change on water temperature characteristics of small lakes in the contiguous U.S., a deterministic, one-dimensional year-round water temperature model is applied. In cold regions the model simulates ice and snow cover on a lake. The lake parameters required as model input are surface area, maximum depth, and Secchi depth as a measure of radiation attenuation and trophic state. The model is driven by daily weather data. Weather records from 209 stations in the contiguous U.S. for the period 1961-1979 were used to represent present climate conditions. The projected climate change owing to a doubling of atmospheric CO2 was obtained from the output of the Canadian Climate Center General Circulation Model. The simulated water temperature and ice characteristics are related to the geometric and trophic state lake characteristics and to geographic location. By interpolation, the sensitivity of lake water temperature characteristics to latitude, longitude, lake geometry and trophic status can therefore be quantified for small lakes in the contiguous U.S. The 2× CO2 climate scenario is projected to increase maximum and minimum lake surface temperatures by up to 5.2°C. (Maximum surface water temperatures in lakes near the northern and the southern border of the contiguous U.S. currently differ by up to 13°C.) Maximum temperature differences between lake surface and lake bottom are projected to increase in average by only 1 to 2°C after climate warming. The duration of seasonal summer stratification is projected to be up to 66 days longer under a 2×CO2 climate scenario. Water temperatures of less than 8°C are projected to occur on lake bottoms during a period which is on the order of 50 days shorter under a 2×CO2 climate scenario. With water temperature change projected to be as high as 5.2°C, ecological impacts such as shifts in species distributions and in fish habitat are most likely. Ice covers on lakes of northern regions would also be changed strongly.

Box, Elgene O., David W. Crumpacker, and E. Dennis Hardin. 1999. "Predicted Effects of Climatic Change on Distribution of Ecologically Important Native Tree and Shrub Species in Florida," Climatic Change, Vol. 41, No. 2, February, pp. 213-248.
ABSTRACT: A previously developed plant species-climatic envelope model was evaluated further and used to predict effects of hypothesized climatic change on the potential distribution of 124 native woody plant species in Florida, U.S.A. Twelve scenarios were investigated. These included mean annual temperature increases of 1 °C or 2 °C, achieved either by equal 1 °C or 2 °C increases on a monthly basis throughout the year, or by disproportionately larger seasonal increases in winter and smaller ones in summer. The various temperature increases were then combined with each of several precipitation changes, ranging from +10% to -20%, to produce the final set of scenarios. More detailed analysis involving six of the scenarios and a subset of 28 representative, ecologically important species suggested that (1) large decreases in the Florida range of many temperate species would result if 1 °C warming occurs predominantly in winter or with a 20% decrease in annual precipitation, or (2) if 2 °C warming occurs, with or without decrease in annual precipitation, and regardless of whether there is a uniform monthly warming pattern or one that is higher in winter than in summer. Available information concerning other factors that might also affect climatic-change responses suggests that these large predicted impacts on temperate Florida species may be underestimates. Subtropical Florida species will tend to move north and inland with warming but extensive human assistance may be needed, if they are to realize their newly expanded, potential natural ranges.