Contributors

Lisa Crozier Department of Zoology University of Washington Seattle, Washington Climate Change and Wildlife Program National Wildlife Federation Washington, D.C. Jessica J. Hellmann Department of Biological Sciences stanford University Stanford, California Laura Koteen Energy and Resources Group University of California, Berkeley Berkeley, California School of Natural Resources and Environment University of Michigan Ann Arbor, Michigan JENNIFER L. ROYVAL Department of Biological Sciences...

Literature Cited

Intergovernmental Panel on Climate Change (IPCC). 2001a. Climate Change 2001 The Scientific Basis, ed. J. T. Houghton, Y. Ding, D. J. Griggs, M. Noguer, P. J. van der Linden, and D. Xiaosu. Contribution of working group I to the third assessment report of the Intergovernmental Panel on Climate Change. Cambridge Cambridge University Press. -.2001b. Climate Change 2001 Impacts, Adaptation, and Vulnerability, ed. J. J. McCarthy, O. F. Canziani, N. A. Leary, D. J. Dokken, and K. S. White....

Blister Rust Index

Blister Rust Index equals the average number of blister rust events that occurred in each blister rust year in a given 5-year period times the number of blister rust years. Year 1 2 BR events Year 2 0 BR events Year 3 5 BR events Year 4 3 BR events Year 5 1 BR event not a BR Year therefore not included in calculation Blister Rust Index (2+5+3 3) 3.33 x 3 10 Note The blister rust index values that appear in the figures are computed through averaging the index values computed for each individual...

Blister Rust Year

At least 2 blister rust events must occur during a single season lasting from July 1 to October 15 of a given year. 2. At least 14 days must elapse between the beginning of the first blister rust event and the end of the next blister rust event. 3. No more than 28 days may elapse between the end of 1 blister rust event and the onset of a second blister rust event. 4.If more than 2 blister rust events occur during a given season (lasting from July 1 to October 15), and both criteria 2 and 3 are...

Criteria for Evaluation of a Blister Rust Event

(only the weather between the time period from July 1 to October 15 was considered for each year) 1. At least 2 consecutive days in which nighttime relative humidity > 90 . 2. At least 2 consecutive days in which daytime relative humidity > 85 . 3. At least 3 consecutive days in which rain > 1 mm and daytime relative humidity is > 85 on any 2 of the 3 days. 4. At least 3 consecutive days in which rain > 1 mm and nighttime relative humidity is > 90 on any 2 of the 3 days. 5. Two...

Acknowledgments

I am deeply grateful to Kristiina Vogt, Daniel Reinhart, and Xuhui Lee for their generous support and guidance over the course of this study. In addition, I am indebted to Jonathan Smith, Phil Farnes, and Martin Dubrovsky for their invaluable creative input and advice. Warm thanks are also in order for Patty Glick, Raymond Hoff, Vanessa Johnson, Kate Kendall, Merle Koteen, Robert Koteen, David Mattson, Larry McDaniel, Linda Mearns, Roy Renkin, Stephen Schneider, Tom Siccama, Peter Thornton,...

Conclusion

This study highlights three potential mechanisms of species loss as a result of global climate change. Acting singly or cumulatively, they may accelerate the decline of an important tree species, whitebark pine, in the Greater Yellowstone Ecosystem. These mechanisms are modified patterns of spread of harmful pathogens, adjustment of species ranges to track locations of preferred climate, and changes in species composition as a result of altered fire regimes. In highlighting the ecosystem...

Region Specific Findings Concerning Climate Variability Historical Climatic Trends and Fire Regimes

Two studies conducted by Balling et al. (1992a, b) and focusing directly on the GYE, concluded that trends toward both warming and increased drought have already occurred in this region. Through examination of weather station data, a mean annual increase in summer temperatures of 0.87 C over the last century was detected (Balling et al. 1992a, 1992b). In addition, employing the Palmer Drought Severity Index (PDSI), Balling et al. (1992a,b) were able to correlate years of large fires with...

Mechanisms of Increasing Fire Frequency

Warmer mean global temperatures, higher precipitation, greater frequency of extreme weather events, increased incidence of convective thunderstorms, and decreases in temperature variability are all features of predicted climate change. If such predictions hold true, fire regimes with shorter fire return intervals will certainly occur in some ecoystems. First, fire weather will be enhanced through temperature increases and concomitant increases in potential evapotranspiration. Second, trends...

Fire Ecology of Whitebark Pine Forests

The northern Rocky Mountain whitebark pine forests currently support fire regimes with typical fire return intervals of 50 to 300 years (Arno 1986). Low intensity fires tend to favor albicaulis in stands where it is seral, as it exhibits relative fire resistance compared to stand cohorts (Bradley et al. 1992, Morgan et al. 1992). Thus fire suppression practices throughout the Northwest, in operation for much of this century, are blamed in part for whitebark pine declines (Kendall and Arno 1990,...

Climate Change and Fire Regime Changes

Climate change is expected to affect forested ecosystems through changes in disturbance regimes, including the frequency, intensity, and extent of fire, windstorms, flooding, avalanches, pathogen outbreaks, and more (Attiwill 1994). Specifically, the establishment of a more intense fire regime may diminish whitebark pine populations in the GYE.The frequency and intensity of fire within an ecosystem are governed by climate, supply of ignition sources, and accumulated forest fuels, which vary in...

Impacts on Genetic Response of Fragmented Populations

As P. albicaulis becomes increasingly fragmented regionally and throughout its range due to ravages from blister rust and fire exclusion, environmental stress and competitive pressures due to climate change will further imperil whitebark pine's survival on the landscape. Over the long term, if whitebark pine continues to decline, its gene pool will shrink, subjecting the species to additional losses associated with low genetic variation (Williams and Kendall 1998). In fact, in anticipation of...

Observations of Species Migrations from Paleoclimatic Studies

Stratigraphic history from within and outside the Yellowstone region, dating from the late Pleistocene, reveal the contribution of large-scale climatic forcings in shaping vegetation provinces over long time scales (Waddington and Wright 1974, Gennett and Baker 1986, 1989, Wigand and Nowak 1992, Whitlock et al. 1994, Whit-lock and Bartlein 1991, 1997). Glacial retreat, changes in the cycle of solar irradiance, and atmospheric circulation patterns have set the altitudinal boundaries of major...

Climate Change Impacts on Species Ranges

Because climate is a primary determinant of vegetation range at large spatial scales, as climate begins to shift, species will migrate in pursuit of optimal conditions. Generally, species are expected to expand their ranges toward the poles and upward in altitude, tracking rising temperatures and altered precipitation patterns, and to contract along their southern and lower elevational margins. Migration patterns will be more complex than simple range shifts, however, as climate is but one of...

Met Roll Climate Change Sensitivity Analysis and Discussion of Results

To examine the potential effects of climate change on the spread of white pine blister rust to whitebark pine in the GYE, a sensitivity analysis was performed by varying monthly mean and interannual variability in precipitation. These variables were chosen because an increase in these statistics is anticipated to hasten the widespread dissemination of blister rust and because these changes match the direction of those predicted by most general circulation models (GCMs) for the region. Moreover,...

I

50-S4 SS-S9 SD-64 65-69 70-74 7S-7S SO-84 85-69 90-94 95-98 Years Figure 8.4. Graphs representing the number of years in which the blister rust cycle was completed, on average, for each 5-year period, computed for elevational bands of 500 feet. Error bars represent the range of values obtained for the pooled stations making up the individual bands. Figure 8.4. Graphs representing the number of years in which the blister rust cycle was completed, on average, for each 5-year period, computed for...

Results of Weather Station Analysis of Baseline Data

The high correlation of the results across elevational gradients obtained (Figs. 8.4 and 8.5) indicate that the described methodology provides an accurate assessment of the historical climatic favor-ability for blister rust transmission in the GYE. The two indices computed for the analysis of 14 SNOTEL and 11 valley stations produced equivalent results and were effective in predicting blister rust events. One predictive index was the number of years in which all the conditions for blister rust...

Methods

To determine the regional trends in climate for the GYE, weather station data that have been recorded for several years on a region-wide basis were used. Of the weather stations that exist, many have been in place in excess of 50 years. These stations are generally found at the lower elevations, and are termed valley sites for the purpose of this study. Beginning in 1981, snow survey telemetry (SNOTEL) sites were established in the higher elevations where P. albicaulis is generally found. These...

Micro to Macro Scale Dynamics of Blister Rust Spread

Additional factors also influence the spread of white pine blister rust on a micro to macro scale. Three phenomena primarily control the degree of infection that will develop among white pine populations within a given year. The first is the initial Ribes infection levels, which are mainly dependent on supply of blister rust inoculum on a local to regional scale. The second mechanism is the intensification, or multiplication, of the blister rust fungus on Ribes leaves, manifest through the...

Past and Current Blister Rust Spread in the GYE

White pine blister rust pathology is initially manifest in whitebark pine through the appearance of a yellow-orange swelling on the tree's bark (Van Arsdel et al. 1956a, Hunt 1983, Tomback et al. 1995). Cankers, which burst through the bark 2 to 4 years after initial infection, grow incrementally both longitudinally and radially over the course of several years (Lachmund 1926, Mielke 1943). Tree mortality arises through girdling of the bole, or after the loss of branches from multiple cankers...

Effects of Global Environmental Change on Pathogen Transmission

The distribution of pathogenic organisms and the hosts that support them is largely controlled by the climatic tolerances of the individual species involved, particularly at large spatial scales (Cammell and Knight 1992, Lonsdale and Gibbs 1994). In the case of white pine blister rust, the extent of the fungus in western North America is confined to the locations where the climate and meteorological conditions are favorable for rust transmission. Currently, few regions exist within the range of...

Notes

For a species to be assigned to this category, it must have either a native range confined to the low elevation tropics and or subtropics or a known naturalized range restricted to the southern half of the United States or to Hawaii, Puerto Rico, Guam, and or other U.S. possessions in the tropics and subtropics. The assignment of species to categories here is based strictly on known native and naturalized ranges and does not consider the mechanisms that limit each species' range. Factors other...

Tamarix

We began our analysis of Tamarix distributions and climate by looking at January mean minimum temperatures and growing season length, to test hypotheses that high altitude and northern limits on Tamarix growth and spread reflect temperature limitations during the growing season or damage by cavitation25 at sufficiently low temperatures. However, no relationships between Tamarix occurrence and either temperature parameter were sufficiently consistent to warrant use in projecting future range...

Case Studies

We chose two study organisms a plant, the exotic shrub Tamarix ramosissima,4 and an animal, the red imported fire ant Solenopsis wagneri5 to illustrate some of the impacts that invasive species have on native wildlife and to explore the effects of global climate change on invasive species distributions. Tamarix and S. wagneri were selected for (1) well-studied impacts on native wildlife, (2) available, reasonably detailed information on distribution throughout the United States, (3)...

The Current State of Knowledge

A number of studies have already deployed climate-matching and other modeling approaches to predicting future changes in impacts of individual invasive species in specific regions. The overall impact in a region of invasives is a function of several factors, only one of which is range size. The number of established invaders in a region (Lonsdale 1999), the abundance or density of a particular invader within its range, and the nature, frequency, and or severity of a particular invader's impacts...

Predicting Future Range Shifts

Quantifying future species range changes can be accomplished with only a limited degree of precision. To begin with, existing models of future climate change lack detailed spatial and temporal resolution. Range shifts may occur on the scale of tens to hundreds of kilometers, while current climate models typically divide the globe into homogeneous 300 km grid cells. Smoothing of topographic features, such as whole mountain ranges, within these grid cells renders model output accuracy uncertain...

Uitl Kl OiT fHII

o. 14 IB fttt -7'f 0 1& C.1& i 06' o. 14 IB fttt -7'f 0 1& C.1& i 06' Figure 6.5b. Changes in vegetation composition. types rather than a single dominant category.The major conclusions of the study are (1) there are likely to be significant changes in the composition of U.S. vegetation under all four assumed scenarios of climate change (2) warmer and drier climates are likely to cause reduction in the prevalence of many coniferous species (e.g., spruce, fir, larch, etc.) and...

Zj fc

Where Af. represents change in probability of prevalence of a vegetation type j. The V index always lies between 0 and 1, with 1 being complete change in vegetation composition and 0 no change. Figure 6.2 shows distribution of the V index computed from the observed fractions of vegetation and those estimated with probability density function under current climate. Figure 6.2 illustrates that OJitaO-a nil VO.IStoCZI tzsi o K C 17 (3134 Figure 6.2. Comparison of the predicted vegetation...

Choice of Independent Variables for a Probabilistic Model

It is important to acknowledge that one could select a different set of independent climate and soil variables and types of vegetation classification to describe bioclimatic relationships. Prentice (1990) argues that any combination of terms has potential, and yet there is no perfect index from a biological point of view. There is widespread acknowledgment that climatic factors such as ambient temperature, incident solar radiation, and water availability play an important role in the...

Modeling Vegetation Climate Relationships with Equilibrium Models

Typically, equilibrium biogeography models are correlative in nature, deterministic, and use heuristics in the form of process-based rules to classify vegetation types for a given set of climatic and soil variables (VEMAP 1995). Most climatic constraints are estimated with rigid environmental-envelope boundaries and ignore interactions among climatic variables (Box 1981).These models are often criticized for lacking causal relationships between climate and plant physiology, and thus their...

Modeling Global Scale Vegetation Climate Interactions

In recent years, the climate change community has taken a number of different approaches toward understanding physical, ecological, and biogeochemical aspects of vegetation-climate interactions. Studies have been performed on different spatial and temporal scales, from an individual leaf to the entire globe (IPCC 1996b). Global impact studies have been performed with biogeography and biochemistry models (e.g., VEMAP 1995). The newly emergent approach is the integrated study of biosphere and...

CHAPTER

Modeling Potential Impacts of Climate Change on the Spatial Distribution of Vegetation in the United States with a Probabilistic Biogeography Approach Elena Shevliakova Anthropogenic activities are leading to rapid changes in land cover and are responsible for emissions of greenhouse gases into the atmosphere, particularly carbon dioxide (CO2).These activities may bring about climatic changes characterized by an increase in average global temperature of 1 to 5 C over the next century and...

Discussion of Empirical Studies

Results from the warming experiment (Price and Waser 1998) suggested that warming will trigger an early flowering of D. nuttallianum by shifting the date of snowmelt however, the evidence was only indirect since warming altered many other microclimate parameters besides snowmelt (Harte et al. 1995). This snow removal experiment corroborated their findings and provided direct evidence that a change in snowmelt date will trigger changes in flower phenology. Moreover, the results suggest that...

Seed Number

After adjusting for fruit position, ANCOVA indicates that flowering time affects seed production (p < 0.0001) overall, early flowers in Figure 5.7. Flowering phenology for the early population (EP) and the late population (LP). Natural observations, 1997. Average frequency of flowers are plotted against Julian date (total number of flowers were transformed to a relative frequency from the maximum number of flowers per plot). Julian date 153 corresponds to June 2. Figure 5.7. Flowering...

How Does Timing of Flowering Affect Reproduction in Natural Populations

Shifting the date of snowmelt experimentally with a warming experiment is one approach for investigating the possible effect of climate change. In order to circumvent the limitations of the experimental approach and to have a better understanding of the fitness consequences of flowering at different dates, I complemented the experimental observations in 1997 with observations of two populations that naturally flower at different times. Flowering time has been a topic of interest for many years....

Info

Average seed weight 1996 and 1997, 2920 and 3170 m sites. US, upper site MS, middle site. Error bars represent 95 comparison limits between control and treatments in the same year-site combination. Table 5.7. Three-way ANOVA. Effect of Snow Removal on Average Seed Weight, Upper and Middle site 1996, 1997 (2599 seeds from 249 individuals). Table 5.7. Three-way ANOVA. Effect of Snow Removal on Average Seed Weight, Upper and Middle site 1996, 1997 (2599 seeds from 249 individuals)....

Results

Average flower number per plant did not respond significantly to snow removal manipulation for either of the two sites in 1997 (p > 0.05) (Table 5.4), nor was a trend evident. In the upper site, plants from the snow removal treatment tended to produce more flowers Table 5.4. Two-way ANOVA. Effect of Snow Removal (1997, 2920 m and 3170 m) on the Average Number of Flowers per Plant. Table 5.4. Two-way ANOVA. Effect of Snow Removal (1997, 2920 m and 3170 m) on the Average Number of Flowers per...

Analysis

Assumptions for ANOVA (normality and homogeneity of the variance) were checked. Average flower number per plant was square root transformed to correct for lack of normality. Seed number was square root transformed before statistical analysis to correct for lack of normality. Since I did not have data for the middle site in 1996, I ran two analyses of variance for seed number, one for the upper site for year 1996-97 and a separate analysis for 1997 for the upper and middle site. For seed weight...

Will Some Components of Fitness in Delphinium Nuttallianum Be Affected by an Early Snowmelt

Inouye and McGuire (1991) found, by relating phenological data from 1973 to 1989 to weather data and snowpack data for the study area, a positive correlation between snowpack accumulation and both D. nuttallianum floral abundance and flowering phenology (high snow accumulation results in more flowers and later flowering). However, the net effect of snowmelt date on plant fitness is not well known, nor is the temporal allocation of plants to flower production. Observations at the global warming...

Study Site and System

The study was carried out in subalpine meadows of the Colorado Rocky Mountains, near the RMBL (38 57N, 106 59'W, 2900 m elevation), in southwestern Colorado. I chose subalpine meadow plants for two reasons. First, mountain environments are expected to be very sensitive to global warming (IPCC 1996a). Second, there is little field experimental work on the impacts of global warming on nonforest environments. I chose Delphinium nuttallianum Pritzel (formerly D. nelsonii Greene) (Ranunculaceae), a...

Modeling Climate Change

A model developed by Arrhenius (1896) quantified for the first time the radiation budget of the atmosphere and the surface. Although Arrhenius lacked modern technology and meteorological data, he was able to create a climate model that agrees remarkably well with modern-day models (Ramanathan and Vogelmann 1997). Arrhe-nius's interest in the greenhouse effect was motivated by his desire to understand temperature variation during the Quaternary, but he applied his results to predict the...

Climate Change Predictions

The greenhouse effect is a natural phenomenon. Trace gases in the atmosphere, such as water vapor (H2O), methane (CH4), and carbon dioxide (CO2), can trap infrared (IR) radiation. As a consequence of these gases, the temperature of Earth's lower atmosphere is about 30 C above that which is expected without them (Rodhe et al. 1997).This natural greenhouse effect is not under debate. However, humans have increased this natural greenhouse effect by adding substantially to some of these trace gases...

Linking Predation and Temperature

This sensitivity of Pisaster predation to small changes in water temperature is particularly surprising because it occurs over the range of 9 to 13 C, in the middle of this sea star's thermal tolerance range. Pisaster ochraceus is found from at least Punta Baja, Baja California, to Prince William Sound, Alaska, and populations living near these Figure 4.7. Results of laboratory predation experiment. Sea stars were maintained under three temperature treatments constant 12 C, constant 9 C, and...

Study System

I conducted research at wave-exposed rocky intertidal sites within Neptune State Park (44 15'N, 124 07'W), south of Cape Perpetua on the central Oregon coast. This 4 km stretch of coastline is composed of extensive rocky benches, outcrops, pools, and surge chan-nels.The communities here are similar to those of many other wave-exposed regions along the northern Pacific coast of North America (Dayton 1971, Paine 1980, Menge et al. 1994).The high intertidal zone is characterized by fucoid algae...

Experiments in a Rocky Intertidal Community

The intertidal zone is the area of the shore that lies between the high and low tide marks, and thus is intermittently exposed and covered by the shifting tides. Rocky intertidal communities in the Pacific Northwest are diverse, accessible, and easy to observe and manipulate. As a result, these communities are extremely well described and have long served as model systems to develop and test general ecological theories about disturbance, succession, and biotic interactions (reviewed by Paine...

Evaluating Community Level Impacts

Is there any empirical evidence that climatic changes can disrupt communities through altered species interactions In fact, some long-term studies have observed interdecadal variation in community structure and have inferred that altered species interactions played a role. For example, a recent study reported that krill abundance in the Antarctic tended to be much lower during the period from 1984 to 1996 than from 1976 to 1984 (Loeb et al. 1997). Declining krill abundance was associated with a...

Temperature and Species Interactions

The potential effects of climate change on natural communities may be underestimated by a focus on the direct, lethal effects of temperature. Many studies have concluded that, at least in the short-term, anticipated warming will have little impact on the ability of a species to survive within its current range (e.g., Johnston and Schmitz 1997, S tersdal and Birks 1997). This conclusion is based on the likelihood that available behavioral and physiological plasticity will minimize the risk of...

Temperature and Species Geographic Ranges

To date, most predictions regarding the potential effects of climate change on wildlife and ecosystems have focused on shifts in species' geographic ranges. Species are expected to respond to warming temperatures by gradually shifting to higher latitudes or altitudes to remain within their thermal tolerance ranges (Breeman 1990, Davis and Zabinski 1992, Gates 1993, Lubchenco et al. 1993). Several recent studies in both marine and terrestrial systems report long-term changes in species...

Future Directions

The most important future direction these historical-descriptive studies can take (beyond the simple step of continued monitoring) is to establish mechanistic links between the observed biological and climatic changes. These mechanisms may be ecological (concerning changes in biological habitats, symbiotic relationships, or changes in species interactions), physical (concerning changes in the structure of the environment in which the species live), or physiological (concerning individuals'...

The Good and the Bad of the Hopkins Studies

The studies at HMS illustrate both the value and the challenges of long-term, historically based research in identifying biological responses to climate change. Perhaps the most important conclusion that can be drawn from these studies is that long-term monitoring programs are essential in attempting to reject alternative hypotheses to climate change as a driver of species or community changes. The dramatic range-related shift in species' abundances we observed, as well as the vertical shift in...

Glynn Study and Other Algal Changes

Marine researchers have predicted that, in the absence of sea-level rise (indeed our surveys show no change in the height of intertidal benchmarks relative to sea level since 1930, see Sagarin et al. 1999), the upper limits of some intertidal species may shift toward lower tidal heights with warming climate (Lubchenco et al. 1993). Other historical studies done at HMS reveal large community-level changes that are consistent with this prediction. Beginning in spring 1994 we relocated seven small...

Model Range Related Changes Are Climate Related

The range-related pattern of change at this site matches expectations of animal populations shifting northward due to climatic warming. Figure 3.9 illustrates diagrammatically how northward shifts in geographic distributions of animals would result in the patterns we observed. Note both a population with a Gaussian distribution of abundance (bell-shaped curves) and a population with abrupt drops in populations at the edges of the range (steep-sided curves) can hypothetically show this pattern....

Climatic Setting

Nearshore sea temperatures have been recorded every day of the year at the HMS since 1920. These records have always been taken by hand with a standard thermometer, so the entire record is technologically consistent. Yearly mean, maximum, and minimum shoreline temperature increased significantly during the period from 1920 to 1995 (Fig. 3.5). Linear regressions for annual mean, maximum, and minimum shoreline temperature for HMS versus year indicate a significant increase of annual sea surface...

Historical Science Defined

In Francis and Hare's (1994) definition, historical-descriptive science begins with observations of a system. At this stage, the obser vations may be anecdotal (e.g., fishermen noticing unusual species in their catches during warm-weather periods) or tangential to a main line of research (e.g., an investigator noticing changes in species composition over many years at a study site). Whatever the source, these observations are intriguing enough that an investigator uses them as a launching point...

Nutrient Deposition

Regional pollution impacts ecosystem nutrient cycling and therefore affects herbivores. Nitrogen, for example, is a limiting nutrient in many ecosystems, and competition among plant species for nitrogen determines the structure of many communities (Vitousek et al. 1997). Nitrogen deposition (e.g., deposition from urban pollution or fertilizer application) can change plant quality and the domi nance hierarchy of vegetation, potentially impacting the suitability of a habitat for an herbivorous...

Habitat Loss

Habitat alteration limits the potential for species to migrate in response to climate change. Many species that once existed in continuous habitat are now found in small habitat patches, separated by degraded habitat, urbanization, and agriculture. Post-Pleistocene patterns of movement suggest that range shifts of hundreds of kilometers may be necessary to keep pace with modern climate change and avoid extinction (Quinn and Karr 1993). Because of habitat fragmentation, however, this scale of...

Additional Impacts on Butterfly Systems

Many human stresses on the environment are superimposed on climate change, and these factors complicate our ability to predict the impacts of the latter. Conversely, any prediction that considers only climate change is narrow organisms will be impacted by many human influences at once. The way that climate and other impacts interact with and feed back on each other can be pieced together only with an understanding of the relative effects of each. By understanding how climate and other factors...

Butterfly Evolution and Climate Change

The possibility of evolutionary responses to climate change renders the preceding discussion of ecological climate consequences incomplete. Many assume that the pace of climate change will be faster than potential rates of evolutionary adaptation for many organisms, causing species intolerant of change to decline or go extinct (Peters and Darling 1985, Hoffmann and Blows 1993). If adaptation to rapid climate change is possible, however, we might expect to find it in short-lived species such as...

Generating Prediction in Butterfly Systems

While a great deal of uncertainty remains in the field of butterfly ecology, the knowledge we do have can serve as an important starting point for exploring the causes and magnitudes of climate impacts in insects and other climate-sensitive species. We can use many of the direct and indirect impacts of climate change in butterflies listed here to build predictions of how much butterfly populations might be altered by human influences on the climate (Roy et al. 2001). Specifically, we can...

Associations with Plants

Associations between Lepidoptera and their larval host plants are remarkably conserved. Related butterfly species are almost always found on related host plants, suggesting that colonization of new hosts is an evolutionary hurdle (Ehrlich and Raven 1965). The number of plant species that a butterfly can consume is thought to be limited by the physiological machinery needed to detoxify plant chemicals (Berenbaum 1995 see Bernays and Graham 1988). Specialized associations with host species create...

Abiotic Limitations

Climatic conditions constitute the third class of range-limiting factors I will consider in this chapter. Favorable climatic periods mark each step in Atalopedes advance. Consideration of physiological constraints and current conditions at the range edge suggests a possible mechanism by which rising minimum temperature may affect this species. I explore physiological constraints with laboratory experiments on cold tolerance and then test their relevance to the range edge with field transplant...

Whitebark Pine and Grizzly Bears

The last remaining grizzly bears in the contiguous United States reside in two major populations one in northwestern Montana and the other in the GYE. All in all, fewer than 1000 grizzly bears now exist where 100,000 once roamed the entire western portion of the United States and Mexico (Craighead et al. 1995). Because of their small size, the existing remnant populations are vulnerable to extirpation and are currently the focus of recovery efforts under the Endangered Species Act (Shaffer...

Climatic Regimes of the Greater Yellowstone Ecosystem

Generally, the climate of the GYE is characterized by long, cold winters and warm, dry summers. Spring and autumn in Yellowstone tend to be short, transitional periods rather than full-fledged seasons (Dirks and Martner 1982, Despain 1987, 1991). Weather systems travel into the area from several locations. Moist air ap proaches from the Gulf of Mexico or the southern Pacific. Drier weather systems reach the area from the west, as maritime air masses shed their moisture over the steep terrain of...

Biotic Limitations

Atalopedes' range expansion has occurred over a time period in which human land use has intensified and human population density has increased. Atalopedes thrives in abandoned lots, lawns, and gardens at densities that are probably higher than they would be in natural prairie habitat. Urbanization is not a sufficient explanation for the range expansion by itself, however. The expansion did not follow the main pattern of urbanization, which would have proceeded along the corridor between...

Western Subalpine Communities

Whitebark pine is the only North American representative of the five Stone pine species, subsection Cembrae, which occupy the subalpine forests of the Northern hemisphere Bingham 1972, Schmidt 1992 . These pines claim a unique history of coevolution with three corvid Corvidae species a relationship that allows them to exploit and pioneer recent stand openings and fresh burns Tomback 1982, Mattes 1992 . In the case of whitebark pine, Clark's nutcracker Nucifraga columbiana is the tree's avian...

Experimental Techniques

The crucial component that is missing in most analyses of animals' distributions is experimental validation that the relevant conditions outside the current range actually reduce performance or survival sufficiently to explain the range edge. Although this type of information may be unattainable for many species, the necessary manipulation is possible for many invertebrates and plants. Experimental introductions or transplants can provide direct evidence for the mechanism of range-limiting...

Francisca Saavedra

Changes in climate will have an impact on community structure and composition by affecting species physiology, distribution, and phenology, which will further lead to changes in species interactions. Some species, especially those with short generation times and rapid population growth, might be able to adapt. However, since climate change is expected to occur at a rate to which many species might not be able to adapt, or shift, we might expect extinction of some species Root 1993, Hughes 2000...

Long Term Faunal Changes at Hopkins Marine Station

Hewatt Transect Hopkins

Our impetus for historical studies of the intertidal zone at Hopkins Marine Station HMS was the observation by Charles Baxter, a Stanford University lecturer, that intertidal species composition had changed dramatically since his arrival at HMS in the late 1970s. In spring 1993, we relocated the original brass bolts that marked an intertidal transect established by W.G. Hewatt in 1931 Figure 3.1. Map of Monterey Bay, California. Figure 3.1. Map of Monterey Bay, California. Hewatt 1934, 1937 at...

Prdation and Parasitism

Evidence suggests that in some systems, pr dation and parasitism are important drivers of population dynamics Dempster 1983, Hassell 1985 . Competition among insect herbivores, in contrast, is thought to be infrequent Strong et al. 1984, but see Denno et al. 1995, Ohgushi 1997 . Direct effects of climate change on the development rates and activity of insect predators can affect butterfly predation Porter 1983, Courtney 1986 . For example, under local cooling, the food requirements of...

Large Scale Spatial Dynamics of Blister Rust Spread

A deeper exploration into the history of blister rust spread in the United States and Canada since its initial introduction may shed light on the prospects for future whitebark pine infection and mortality within the GYE, and is therefore examined here. Specifically, consideration of the spatial and temporal dimensions of past C. ribi-cola invasion into regions of different vegetation, topographic, and climatic regimes yields insights into the factors that control and limit blister rust spread....

Laura Koteen

The subalpine tree species whitebark pine Pinus albicaulis faces multiple threats to its existence. Predominant among them is the risk posed by the exotic fungus white pine blister rust, Cronartium ribicola . Throughout much of its range Fig. 8.1 , whitebark pine has suffered considerable losses approaching 90 in some locations. Blister rust, mountain pine beetle Dendroctonus ponderosae and successional replacement by subalpine cohorts due to fire exclusion account for the bulk of its...

Design of Field and Laboratory Experiments

Mussel Transplantation

Using field experiments, I quantified rates of Pisaster predation to test the hypothesis that the strength of the sea star-mussel interaction is reduced during periods of cold-water upwelling. Experiments were conducted at three wave-exposed sites within Neptune State Park. Sites were separated by several hundred meters, and water temperatures varied little generally lt 0.2 C over these distances. At each site, I identified two large rocky reefs mean area SEM 132.5 49.7 m2 that were in close...

Nonparametric Density Estimation Method

Once a set of climatic variables is identified, multivariate nonpara-metric density estimation is applied to estimate probability density functions of each vegetation type. Nonparametric density estimation methods are well understood and have been increasingly used in practice for both univariate and multivariate analysis in such areas as chemical and electrical engineering and medical biostatis-tics. A comprehensive review of different density estimation methods can be found in Silverman 1986...

Index

See subalpine fir abrupt climate changes, 38-39. See also extreme weather events Adams, C.T., 304 adaptability factors, 40 Adelie penguins, 155, 171-72 alpine buttercup Ranunculus adoneus , 208-9 alpine chaenactis Chaenactis alpinus , 389 records on, 131 Anderson, B.W., 308 animals. See also invertebrate species mammals specific species current responses of, 22-25 projecting responses by, 19-22 and vegetation, 29-30 Antarctic penguins, 155 Anthocharis caramines British...

Potential Changes in Rocky Intertidal Communities

How might rocky intertidal communities along the central Oregon coast be impacted by changes in the frequency and intensity of upwelling My results suggest that a long-term reduction in cold-water upwelling would cause Pisaster feeding rates to remain consistently high rather than fluctuating. In this case, sustained sea star predation might diminish the vertical extent of the mid-zone mussel beds by shifting the lower limit of these beds to a higher level on the shore. Since mussel beds...

Examples of Ecological Responses to Climate Changes

Bringing climatic forecasts down to ecological applications at local and regional scales is one way to bridge the scale gap across ecological and climatological studies. Ecologists, however, have also analyzed data and constructed models that apply over large scales, including the size of climatic model grids. A long tradition in ecology has associated the occurrence of vegetation types or the range limits of different plant species with physical factors such as temperature, soil moisture, or...

Blister Rust Life Cycle

White Pine Blister Rust Life Cycle

The dynamics of the blister rust life cycle reveal the major climatic limitations for the spread of blister rust to whitebark pine. In pines, the blister rust cycle Fig. 8.3 commences in the summer a year or more after pine infection when spermatia, the initial spore stage, form in nectarlike droplets that ooze from the bark. These spores are transmitted by rain or insects that are attracted to the nectarlike exudate and travel from canker to canker. If successfully sperma-tized, the...

Prospects for Future Range Expansions The Red Imported Fire

Abundant evidence of northward temperature limitations on ant distributions led us to begin by examining relationships between January mean minimum temperatures and the occurrence of RIFA. We selected winter temperature minima rather than other temperature-related variables such as growing season length because experimental evidence indicates that absolute temperature minima, not summer or active season minima, drive mortality and brood failure in RIFA. In addition, growing season length...

Tamarix Shrubs in the Wests Riparian Zones

Invasive shrubs of the genus Tamarix18 do not pose the direct threats to human health or agriculture that S. wagneri does. As a result, far less is known about Tamarix and, in general, far less attention has gone to its adverse impacts as it spreads through the western United States. In spite of the serious impacts that it has on water quality and supplies Johns 1990, Wiesenborn 1996 , the frequency and severity of floods Graf 1980, Blackburn et al. 1982 and native wildlife DeLoach 1997 in 23...

Butterfly Ranges and Climate

Research at many scales clearly shows that climate is important for butterfly abundance and distribution. The basic association between climate and insect distribution and abundance has been studied for at least 70 years e.g., Uvarov 1931, Andrewartha and Birch 1954, Birch 1957, Dennis 1993 .The challenge now is to focus on experiments that will integrate our mechanistic understanding of individual and population processes with distribution limits and change. Large-scale patterns in butterfly...

The Red Imported Fire Ant in the American Southeast

Red imported fire ants Solenopsis wagneri have rapidly invaded the southeastern United States in this century. Since their introduction approximately 80 years ago, they have colonized millions of hectares at densities 4 to 10 times higher than those found in their native habitat of Brazil Porter et al. 1997 . Economic losses due to agricultural damage and direct threats to human health have prompted careful monitoring and study of red imported fire ants RIFA since as early as 1930, providing...

Predicting Changes in Upwelling Intensity

To what extent can we predict how global warming will alter patterns of upwelling along the Pacific coast of North America Coastal upwelling is a complex process affected by atmospheric and oceanic conditions at local, regional, and hemispheric scales Barber 1988 . The intensity of upwelling i.e., the temperature of upwelled waters and its frequency i.e., the duration of events and number of events per season varies naturally from year to year and among different sites along the coast....

Examples of the Historical Method in Action

Recently, a handful of papers have used some form of this historical-descriptive method to demonstrate evidence of species' responses to climate changes that have occurred over the last century. Barry et al. 1995 and Sagarin et al. 1999 documented a general increase in southern invertebrate species and a decrease in northern species between two investigations of a single intertidal site conducted 60 years apart. This faunal change was concomitant with an increase in mean annual shoreline ocean...

Verifying Climate Forecasts

The most perplexing question about climate models is whether they can be trusted as a reliable basis for altering social policies, such as those governing CO2 emissions or the shape and location of wildlife reserves. Even though these models are fraught with uncertainties, several methods are available for verification tests. Although no method is sufficient by itself, several methods together can provide significant, albeit circumstantial, evidence of a forecast's credibility. The first...

Does Snowmelt Date Affect the Flowering Time of Delphinium Nuttallianum

Price and Waser's 1998 observations on the global warming experiment at the RMBL Harte et al. 1995, Harte and Shaw 1995 suggested that if winter precipitation patterns in the form of snow don't change, flowering date will shift with global warming by shifting the snowmelt date. If precipitation changes, these predictions could fail. Current models of climate change, however, have no clear predictions about whether precipitation will increase or decrease at a regional level. The most likely...

Atalopedes campestris A Case Study

Atalopedes campestris, the sachem skipper, is a common, generalist butterfly in the family Hesperiidae subfamily Hesperiinae grassfeeding skippers Scott 1986 . It is the only member of its genus that extends beyond the neotropics. A. campestris ranges from south of the equator into the United States Burns 1989 . In the central and eastern United States it frequently disperses northward in mid to late summer, but it dies out over winter and contracts to a permanent range in the southern states...

Qualitative Responses to Climate Change

In the absence of evolutionary change, populations have four possible responses to climate change expand, decline, move, or go extinct see Cohn 1989, Peters and Lovejoy 1992, Gates 1993, Kareiva et al. 1993 . If climate change improves the quality or total area of suitable habitat e.g., removing abiotic or biotic barriers to occupancy , populations can expand or increase in density and new populations can be established. Alternatively, if climate change impacts a species negatively, populations...