Publications Published in Global Change Biology

1. BIOMOD - optimizing predictions of species distributions and projecting potential future shifts under global change. Thuiller, Wilfried.
   Global Change Biology: 2003
   Notes
   A new computation framework (BIOMOD: BIOdiversity MODelling) is presented, which aims to maximize the predictive accuracy of current species distributions and the reliability of future potential distributions using different types of statistical modelling methods. BIOMOD capitalizes on the different techniques used in static modelling to provide spatial predictions. It computes, for each species and in the same package, the four most widely used modelling techniques in species predictions, namely Generalized Linear Models (GLM), Generalized Additive Models (GAM), Classification and Regression Tree analysis (CART) and Artificial Neural Networks (ANN). BIOMOD was applied to 61 species of trees in Europe using climatic quantities as explanatory variables of current distributions. On average, all the different modelling methods yielded very good agreement between observed and predicted distributions. However, the relative performance of different techniques was idiosyncratic across species, suggesting that the most accurate model varies between species. The results of this evaluation also highlight that slight differences between current predictions from different modelling techniques are exacerbated in future projections. Therefore, it is difficult to assess the reliability of alternative projections without validation techniques or expert opinion. It is concluded that rather than using a single modelling technique to predict the distribution of several species, it would be more reliable to use a framework assessing different models for each species and selecting the most accurate one using both evaluation methods and expert knowledge.
   
   
   
2. Changes in spring arrival of Nearctic-Neotropical migrants attributed to multiscalar climate. MacMynowski, Dena P.; Root, Terry L.; Ballard, Grant; Geupel, Geoffrey R..
   Global Change Biology: 2007
   DOI: 10.1111/j.1365-2486.2007.01448.x
   Notes
   Climate-related changes associated with the California marine ecosystem have been documented; however, there are no studies assessing changes in terrestrial vertebrate phenology on the Pacific coast of western North America. We analyze the spring phenology of 21 Nearctic-Neotropical migratory songbird species in central and northern CA. Using observational and banding data at multiple sites, we evaluate evidence for a change in arrival timing being linked to either nonclimatic or multiscalar climatic explanations. Using correlation analysis, of the 13 species with a significant (Po0.10) change in arrival, the arrival timing of 10 species (77%) is associated with both temperature and a large-scale climate oscillation index (El Nin˜o Southern Oscillation, ENSO; North Atlantic Oscillation, NAO; and/or Pacific Decadal Oscillation, PDO) at least at one location. Eight of the 13 species (62%) are advancing their migratory timing. All species for which spring arrival is associated with climate at multiple locations e exhibiting changes (n55) and all species lacking evidence for association between migration phenology and climate (n53) exhibit no change. Migrants tend to arrive earlier in association with warmer temperatures, positive NAO indices, and stronger ENSO indices. Twelve species negatively correlate (P 0.05) with local or regional temperature at least at one location; five species negatively correlate with ENSO. Eleven species’ arrival is correlated (P 0.05) with NAO; 10 are negatively associated. After an exhaustive literature search, this is apparently the first documentation of an association between NAO and migratory phenology in western North America.
   
   
   
3. Climatic trends and advancing spring flight of butterflies in lowland California. Forister, M. L.; Shapiro, A. M..
   Global Change Biology: 2003
   Notes
   Many studies, largely from cool-temperate latitudes, have investigated the relationship between the timing of biological events and changes in climatic conditions during the past few decades. Relatively little is known about the response of plants and animals at lower latitudes. Here we show that the average first spring flight of 23 butterfly species in the Central Valley of California has advanced to an earlier date over the past 31 years. Among the species that have appeared significantly earlier, the average shift is 24 days. Climatic conditions (largely winter temperature and precipitation) are found to explain a large part of the variation in changing date of first flight. These results suggest a strong ecological influence of changing climatic conditions on a suite of animals from a mid-latitude, Mediterranean climate.
   
   
   
4. Effect of CO2 enrichment and elevated temperature on methane emissions from rice, Oryza sativa. Schrope, M K; Chanton, J P; Allen, L H; Baker, J T.
   Global Change Biology: 1999
   Notes
   Methane emissions from rice grown within Temperature Gradient Greenhouse Tunnels under doubled CO
   
   
   
5. Effects of elevated CO2 on the protein concentration of food crops: a meta-analysis. Taub, Daniel R.; Miller, Brian; Allen, Holly.
   Global Change Biology: 2008
   DOI: doi:10.1111/j.1365-2486.2007.01511.x
   Notes
   Meta-analysis techniques were used to examine the effect of elevated atmospheric carbon dioxide [CO2] on the protein concentrations of major food crops, incorporating 228 experimental observations on barley, rice, wheat, soybean and potato. Each crop had lower protein concentrations when grown at elevated (540-958 mumol mol-1) compared with ambient (315-400 mumol mol-1) CO2. For wheat, barley and rice, the reduction in grain protein concentration was ~10-15% of the value at ambient CO2. For potato, the reduction in tuber protein concentration was 14%. For soybean, there was a much smaller, although statistically significant reduction of protein concentration of 1.4%. The magnitude of the CO2 effect on wheat grains was smaller under high soil N conditions than under low soil N. Protein concentrations in potato tubers were reduced more for plants grown at high than at low concentrations of ozone. For soybean, the ozone effect was the reverse, as elevated CO2 increased the protein concentration of soybean grown at high ozone concentrations. The magnitude of the CO2 effect also varied depending on experimental methodology. For both wheat and soybean, studies performed in open-top chambers produced a larger CO2 effect than those performed using other types of experimental facilities. There was also indication of a possible pot artifact as, for both wheat and soybean, studies performed in open-top chambers showed a significantly greater CO2 effect when plants were rooted in pots rather than in the ground. Studies on wheat also showed a greater CO2 effect when protein concentration was measured in whole grains rather than flour. While the magnitude of the effect of elevated CO2 varied depending on the experimental procedures, a reduction in protein concentration was consistently found for most crops. These findings suggest that the increasing CO2 concentrations of the 21st century are likely to decrease the protein concentration of many human plant foods.
   
   
   
6. Enhanced growth of sagebrush (Artemisia tridentata ) in response to manipulated ecosystem warming.. Perfors, TRACY; Harte, JOHN; Alter, S. ELIZABETH.
   Blackwell Publishing Limited Global Change Biology: 2003
   Notes
   Abstract Global models project impending climate changes that could significantly alter plant species composition in ecosystems. Climate manipulation experiments provide an opportunity to investigate such effects. Here we describe and apply a method for extracting the age-detrended growth rate of sagebrush (Artemisia tridentata Nutt.) and show that experimental ecosystem warming enhances the growth rate of this shrub. Snowmelt date, not soil temperature or moisture, is demonstrated to be the dominant climate variable controlling the observed effect. Our findings suggest that global climate change will result in increased growth and range expansion of sagebrush near northern or high-elevation range boundaries in the Western United States.
   
   
   
7. Estimation of the CO2 fertilization effect using growth rate anomalies of CO2 and crop yields since 1961. Lobell, David B.; Field, Christopher B..
   Global Change Biology: 2008
   DOI: doi:10.1111/j.1365-2486.2007.01536.x
   Notes
   The effect of elevated carbon dioxide (CO
   
   
   
8. Feedback significantly influences the simulated effect of CO2 on seasonal evapotranspiration from two agricultural species. Wilson, Kell B; Carlson, Toby N; Bunce, James A.
   Global Change Biology: 1999
   Notes
   The direct effect of elevated carbon dioxide on evapotranspiration over a growing season was investigated by scaling up single-leaf gas exchange measurements on soybean and corn plants grown and measured at three carbon dioxide concentrations. Stomatal conductance decreased markedly with increasing carbon dioxide in these species under most conditions. Coupled soil–vegetation–atmosphere models were used to scale up these single-leaf level measurements to simulate evapotranspiration at the regional scale from planting to harvest. The coupled modelling system introduced feedbacks over the season that are not present at the measurement level, which decreased the effect of carbon dioxide on evapotranspiration. Four sets of simulations were performed to evaluate specifically the magnitude of four feedbacks; two resulting from scale, surface layer and mixed layer feedback, one resulting from soil evaporation and one resulting from the interactions of stomatal conductance and the simulated canopy microclimate (physiological feedback). The feedbacks occurring from scale were consistent with previous analytical work indicating that transpiration becomes less dependent on stomatal conductance at larger scales. Evaporation from the soil has been generally neglected in past studies on carbon dioxide effects, but was especially important in decreasing the effects of carbon dioxide on evapotranspiration and showed a seasonal dynamic. The feedback resulting from physiological responses has also received less attention than the feedbacks from scale, but was only moderately important in these simulations. We also investigated the seasonal dynamics of how the observed increase in leaf area at elevated carbon dioxide affects evapotranspiration. Considering all the feedbacks and the observed increase in leaf area at elevated carbon dioxide, the simulated decrease in evapotranspiration was not negligible but was much less than the decrease in stomatal.
   
   
   
9. Impacts of climate change on natural forest productivity – evidence since the middle of the 20th century. CE´ L I N E BOISVENUE, S T EVEN W. RUNNING.
   Global Change Biology: 2005
   DOI: 10.1111/j.1365-2486.2006.01134.x
   Notes
   Changes to forest production drivers (light, water, temperature, and site nutrient) over the last 55 years have been documented in peer-reviewed literature. The main objective of this paper is to review documented evidence of the impacts of climate change trends on forest productivity since the middle of the 20th century. We first present a concise overview of the climate controls of forest production, provide evidence of how the main controls have changed in the last 55 years, followed by a core section outlining our findings of observed and documented impacts on forest productivity and a brief discussion of the complications of interpreting trends in net primary production (NPP). At finer spatial scales, a trend is difficult to decipher, but globally, based on both satellite and ground-based data, climatic changes seemed to have a generally positive impact on forest productivity when water was not limiting. Of the 49 papers reporting forest production levels we reviewed, 37 showed a positive growth trend, ive a negative trend, three reported both a positive and a negative trend for different time periods, one reported a positive and no trend for different geographic areas, and two reported no trend. Forests occupy 52% of the Earth’s land surface and tend to occupy more temperature and radiation-limited environments. Less than 7% of forests are in strongly water-limited systems. The combined and interacting effects of temperature, radiation, and precipitation changes with the positive effect of CO2, the negative effects of O3 and other pollutants, and the presently positive effects of N will not be elucidated with experimental manipulation of one or a few factors at a time. Assessments of the greening of the biosphere depend on both accurate measurements of rates (net ecosystem exchange, NPP), how much is stored at the ecosystem level (net ecosystem production) and quantification of disturbances rates on final net biome production.
   
   
   
10. Intercomparison, interpretation, and assessment of spring phenology in North America estimated from remote sensing for 1982–2006. White, Michael A.; de Beurs, Kirsten M.; Didan, Kamel; Inouye, David W.; Richardson, Andrew D.; Jensen, Olaf P.; O'Keefe, John; Zhang, Gong; Neman, Ramakrishna R.; van Leeuwen, Willem J.D.; Brown, Jesslyn F.; de Wit, Allard; Schaepman, Michael; Lin, Xioamao; Dettinger, Michael; Bailey, Amey S.; Kimball, John; Schwartz, Mark D.; Baldocchi, Dennis D.; Lee, John T.; Lauenroth, William K..
    Global Change Biology: 2009
    DOI: 10.1111/j.1365-2486.2009.01910.x
    Notes
    Shifts in the timing of spring phenology are a central feature of global change research. Long-term observations of plant phenology have been used to track vegetation responses to climate variability but are often limited to particular species and locations and may not represent synoptic patterns. Satellite remote sensing is instead used for continental to global monitoring. Although numerous methods exist to extract phenological timing, in particular start-of-spring (SOS), from time series of reflectance data, a comprehensive intercomparison and interpretation of SOS methods has not been conducted. Here, we assess 10 SOS methods for North America between 1982 and 2006. The techniques include consistent inputs from the 8 km Global Inventory Modeling and Mapping Studies Advanced Very High Resolution Radiometer NDVIg dataset, independent data for snow cover, soil thaw, lake ice dynamics, spring streamflow timing, over 16 000 individual measurements of ground-based phenology, and two temperature-driven models of pring phenology. Compared with an ensemble of the 10 SOS methods, we found that individual methods differed in average day-of-year estimates by 60 days and in standard deviation by 20 days. The ability of the satellite methods to retrieve SOS estimates was highest in northern latitudes and lowest in arid, tropical, and Mediterranean ecoregions. The ordinal rank of SOS methods varied geographically, as did the relationships between SOS estimates and the cryospheric/hydrologic metrics. Compared with ground observations, SOS estimates were more related to the first leaf and first flowers expanding phenological stages.We found no evidence for time trends in spring arrival from ground- or model-based data; using an ensemble estimate from two methods that were more closely related to ground observations than other methods, SOS trends could be detected for only 12% of North America and were divided between trends towards both earlier and later spring.