U.S. Department of Energy’s Office of Science

1. U.S. Department of Energy’sOffice of Science Climatic Change: Program for Ecosystem Research* Background, Status, and Strategy BER Advisory Committee – Spring Meeting Jeffrey S. Amthor May 19, 2008 *See http://per.ornl.gov

2. Climatic change is about ecosystems (and economies, food supply, and human health) Parties* to the United Nations Framework Convention on Climate Change or UNFCCC (1992) were: “Concerned that human activities have been substantially increasing the atmospheric concentrations of greenhouse gases, that these increases enhance the natural greenhouse effect, and that this will result on average in an additional warming of the Earth’s surface and atmosphere and may adversely affect natural ecosystemsand humankind.” The UNFCCC defined: “Adverse effects of climate change” as “changes in the physical environment or biota resulting from climate change which have significant deleterious effects on the composition, resilience or productivity of natural and managed ecosystems or on the operation of socio-economic systems or on human health and welfare.” Emphases added *The United States ratified the Climate Change Convention on October 15, 1992

3. Climatic change is about ecosystems (and economies, food supply, and human health) --- continued The stated “ultimate objective” of the UNFCCC: “…is to achieve…stabilization of greenhouse gas concentrations in the atmosphere at a level that would prevent dangerous anthropogenic interference with the climate system. Such a level should be achieved within a time frame sufficient to allow ecosystems to adapt naturally to climate change, to ensure that food production is not threatened [food comes from ecosystems] and to enable economic development to proceed in a sustainable manner.” Emphases added “Dangerous” is not defined by the UNFCCC, but “adverse effects” of climatic change means “deleterious effects” on ecosystems, socio-economic systems, or human health and welfare. To be clear — the “so what” of climatic change is whether it affects ecosystems, social and economic systems, or human health.

4. The Program for Ecosystem Research conducts basic research The program goal is to produce scientific knowledge about the potential effects of climatic change on terrestrial ecosystems. ● The program fosters multidisciplinary research intended to integrate knowledge across different levels of organization so that effects at the whole-ecosystem scale are understood. ● The focus is on understanding the mechanisms underlying potential ecological effects of climatic change so that prediction is possible. ● The approach emphasizes manipulative experiments because with respect to climatic change and ecosystems we cannot predict the future from the past— the expected magnitudes and rates of climatic change during this century will be too large and too fastto be related to history.

5. Research funding began in FY 1993 In FY 2008 there are 25 active projects(31 awards; four multi-institutional collaborations). Awards range from $200,000 to $1,108,180. There were 29 “previous projects” (i.e., projects completed or now funded from other sources). There have been 10 competitive solicitations (five jointly with other agencies). Projects are also funded under annual notices. Nine PIs (30%) are female; 21 are male. Median date of PI’s Ph.D. is 1990/1991. “High risk research having the potential to rapidly advance the field is encouraged” (FOA 07ER07-11). Excludes “taxes” and “earmarks”

6. The program’s field and laboratory experiments (mostly in the field) are studying effects of four key climatic change factors on processes and states in several important ecosystem types. Twenty-six (26) institutions are funded directly and eighteen (18) are funded through subawards. Other institutions use non-BER funds to collaborate on the program’s research projects.

7. Research spans a wide range of scales and levels of organization Research is conducted on: ● “Small” and “large” model ecosystems,mathematical models, and natural ecosystems. ● Enzymes, organs (leaves, roots), organisms (plants, animals), populations, communities, and ecosystems. Effect of damage by Japanese beetles under the individual and combined effect of elevated CO2 and O3 on the transcription of genes that may affect leaf palatability to insects.

8. Niche in U.S. climatic change research Eight federal agencies contribute to the U.S. Climate Change Science Program’s (CCSP’s) ecosystems research element. There are several “types” of CCSP ecosystems research: ● Observations of the present and the past (ground- and space-based) ● Modeling of the future (varying in degrees of mechanism) ● Experimental studies directed at the future (varying in scope) The BER program is the main U.S. sponsor of long-term, multi-investigator manipulative field experiments capable of quantifying cause-and-effect relationships between climatic change and ecosystem-scale processes. This is the most important climatic change–ecosystems research there is. It can greatly facilitate mechanistic predictions of effects of climatic change on ecosystems.

9. 80 m 240 m Long-term precipitation manipulation The program’s Throughfall Displacement Experiment (TDE) was the pioneering field manipulation of precipitation at the ecosystem scale. There were 13 years (1993–2006) of ±33% of ambient forest throughfall. Ecosystem models used to predict effects of reduced precipitation on deciduous forests often indicate large reductions in tree growth and altered ecosystem functioning. The TDE tested these predictions. The ORNL TDE The experimental approach was passive (no moving parts)

10. TDE treatments did affect the forest Increased throughfall enhanced seedling (and sapling) survival; reduced throughfall reduced seedling (and sapling) survival. This effect on seedling and saplings has implications for longer term ecosystem development (i.e., successional changes). Large trees (10+ cm diameter) were quite resilient to the treatments, but effects were apparent after 10 years—it was worth the wait. Large-tree growth was affected by the treatments, but this was not apparent in the “short term.” We now know that many ecosystem models are too sensitive to precipitation change.

11. Trees can acclimate to multi-year warming Aspen, birch, oak, and sweetgum trees were grown for 4 years in field chambers, in the soil. Temperature was ambient, +2°C, and +4°C. The leaf photosynthesis–temperature response curve acclimated to warming, and so did leaf-level respiration rate. This type of response has been reported before, but this was the first study to use multi-year controlled temperature treatments for field-like conditions. Growth increased up to 29% with warming for the “warm climate” species, but was not affected for the cool climate species (not shown).

12. Ozone affects forest CO2 fertilization The program’s elevated CO2 and O3 field experiment in Wisconsin is the world’s largest study of ecological effects of changes in atmospheric composition. Starting in 1998, summer O3 and CO2 concentrations were increased ~50% above ambient levels (singly and in combination); these levels are thought to be relevant to ca. 2050. Multiple agencies use this facility. There are 12 30-m-diameter “rings” As expected, CO2 stimulated tree growth and O3 slowed tree growth. A critical novel finding was that the effects were not additive. This means that “additive models” would fail to reflect the likely future. Wood growth from 1997 through 2003, relative to ambient conditions

13. The forest CO2/O3 experiment is ending The program’s elevated CO2/O3 experiment has been immensely successful, but it is time to bring the experiment to a conclusion. ● Program resources must now be focused on warming (and warming in combination with elevated CO2), and multiple levels of warming and CO2 concentration must be considered in new experiments. ● In early 2006, the program began planning for a project wrap-up; in late 2006 a BERAC subcommittee recommended that this occur by 2010. ● A large-scale destructive harvest of trees and soil will allow a full assessment of effects of 10+ years of treatment on the experimental ecosystems (compared to the relatively non-invasive measurements conducted during the experiment). ● A plan is in place to end the CO2 and O3 treatments in 2009, and to complete the harvest and analysis of trees and soil by 2011.

14. Warming may threaten dryland ecosystems More than 33% of the United States is dryland (arid, semi-arid). Dryland plants are already living “on the edge” and might be especially sensitive to climatic change. One program warming experiment is in a Utah dryland (joint w/USGS). In plots warmed only 2°C with infrared lamps (relative to ambient control plots) about 40% of the dominant grass (Hilaria jamesii) perished in 2 years. The western United States is expected to be ~2°C warmer by 2050, and perhaps 4–5°C warmer by 2100. Loss of vegetation could lead to increased soil erosion and would affect the health and success of animal species throughout the food chain. This study is expanding to include warming up to 5°C, with plots on two soil types. Precipitation is also being manipulated. So far, changes in rain event frequency have affected the biological communities living on the soil surface (the biological soil crust).

15. Interlude — simulating a specific future environment is not the goal The program is not attempting to simulate a specific future climate at a specific location in order to simulate a future ecosystem. Basic research is conducted to understand mechanistic relationships between climate and ecological processes. This process understanding is needed to predict ecological effects of climatic change across a wide range of ecosystems and geographies. Research on a few specific “simulated future” climate-ecosystem combinations might be of limited utility in building a robust ecological forecasting capability. Precise local-scale climatic change predictions (especially with respect to precipitation) are beyond the capability of present climate models. We cannot wait for perfection of climate models —ecological process understanding must be improved now.

16. The program must focus on climatic variables of first order importance • We judge the most important climatic change variables to be: • ● Warming • ● Increasing CO2 concentration • ● Changes in precipitation (amount and temporal distribution) • ● Combinations of warming, CO2, and precipitation change • Ecosystems and processes studied must bevalued by society.

17. Drought damage in the southwest Recent mortality of pinyon pine (40-95%); juniper (2-25%); and ponderosa pine, Douglas-fir, and white fir (10-60%) in the southwest was blamed on drought.Will the projected increase in southwestern water deficit cause significant plant mortality in the region? Yellow to red pixels indicate loss of “green” pinyon pine after the 2002 drought (based on changes in summer Normalized Difference Vegetation Index [NDVI] for pixels containing significant pinyon pine populations). A USFS aerial survey of mortality in pinyon-juniper (PJ) woodlands corroborated the NDVI analysis. The yellow fraction of each circle is percent tree mortality in each of four study areas. The 1989-1999 predrought mean NDVI minus 2002-2003 post-drought NDVI. Maps from Breshears et al. (2005) PNAS

18. The program’s new pinyon-juniper experiment (in NM) Replicated TDE approach with pumps and sprinklers (some moving parts). Treatments: ambient, +50%, and –50% precipitation; 40 x 40 m plots. Science question: what is the cause of mortality? Xylem cavitation, carbon starvation, insect attack, or a combination?

19. Fire is an important factor in southern California: now and later Fire is an important ecological (and non-ecological) factor in southern California. Climatic change could affect its extent, timing, and severity. Fire also affects our present field research. One of 11 major southern California wildfires burning October 21, 2007 Santiago fire: during and after

20. Warming could move geographic ranges A species’ geographic range can be defined as “where it is found.” It is often assumed that the poleward (or higher-elevation) edge of the range of plants and animals is related to a low-temperature limit of some sort. The equatorially facing edge may represent a high-temperature limit. (In the case of red oak, the western edge may be controlled by precipitation.) Warming could “displace” the ranges of plants and animals, but local adaptation might present a problem. We have been studying this. The “native range of northern red oak” (USFS).

21. A new research priority in FY 2007 Do temperature increases projected by coupled atmosphere-ocean general circulation models for the coming 100 years have the potential to affect the abundance and/or geographic distribution of plant or animal species in the United States, and if so, to what extent? New cause-and-effect-relationship experiments related to projections of future warming were requested in the 2007 solicitation to address two specific questions: (1) Might terrestrial vascular-plant or animal species near the “warm” end of their range in the United States decline in abundance during the coming 100 years because of projected warming? and/or (2) Might terrestrial vascular-plant or animal species near the “cool” end of their range in the United States increase in abundance, or extend their range, during the coming 100 years because of projected warming?

22. New “range edge” experiments Five new (high-risk) experimental warming projects: ● Field experiments in the boreal–temperature forest ecotone (mechanisms of warming-induced northern migration of the ecotone). ● Field experiments in the eastern temperate forest (potential tree species changes at the southern and northern biome edges) ● Field experiment at the alpine tree line (more in a minute). ● Field experiment directed at important ant species in the eastern temperate forest (including fire ants); +5°C, by 0.5°C increments. ● Laboratory experiments with a model ectotherm (striped ground cricket; using multi-generation, incremental temperature increases over 5 years[90-year GFDL warming scenario], three local climates as base). These experiments are a big step forward. The investigators were forced (by the solicitation) to plan innovative experiments that directly study potential effects of warming on terrestrial organisms; this goes far beyond climate-ecosystem observational correlations from the past.

23. Warming and the alpine tree line Warming and the alpine tree line Warming of 4°C corresponds to ~600 m elevation change. Temperature may control tree line elevation, so warming this century has the potential to move tree lines above many peaks in the western United States. Any upward tree line migration threatens alpine species, communities, and ecosystems. There are energy balance issues too. This would also be true for “northern migration” of arctic tree lines into tundra. We just initiated temperature and moisture manipulations at (and above) the alpine tree line to study the potential for, and mechanisms of, warming-induced upslope tree line migration. Tree lines may join glaciers as global warming “poster children,” so we must understand them better.

24. Manipulative experiments are needed • To repeat — the program focuses on manipulative experiments because: • ● Expected future climate-ecosystem combinations are (well) outside the envelope of climate-ecosystem combinations of the past, so the past is not a good surrogate for the future. • ● Mechanistic understanding is needed for prediction and this comes from properly designed manipulative experiments. • A critical need is improved methods for field manipulations of climatic variables. (More on this in a few minutes)

25. Program progress has been excellent The NRC (2001*, p. 2) claimed that “insufficient progress has been made in analyzing…ecosystem…responses to environmental change....” Since that claim: ● The 13-year Throughfall Displacement Experiment was completed. ● The Wisconsin FACE study collected 6 more years of one-of-a-kind data. ● The New Mexico precipitation study was designed and implemented. ● Seven unique warming experiments were designed and implemented. ● Novel biochemical studies in an ecosystem context were conducted. ● Field studies of potential ecosystem “state changes” caused by climatic change were initiated. These, and other, program activities are making excellent progress toward understanding the importance of climatic change. We acknowledge that more is still needed. *The Science of Regional and Global Change: Putting Knowledge to Work

26. Conclusions The DOE Program for Ecosystem Research is a unique and critical part of the DOE climatic change research program. It is also a key component of the Ecosystems element of the 13-agency CCSP. ● It is addressing one of the key “so what” question about climatic change. ● It is providing the research community with unique experimental “facilities” needed to understand ecological effects of changes in climate and atmospheric composition caused by energy production. ● It is pushing the research community to use new approaches to answer emerging scientific questions about climatic change.

27. Questions?