Climate change information: UK Hadley Centre

1. Climate change information: UK Hadley Centre http://www.metoffice.gov.uk/research/hadleycentre/

2. What makes a species invasive? • c) Environmental <Global> Change Hypothesis • Global Changes • Increasing atmospheric CO2 • Changes in temperature • Changes in precipitation • Nitrogen deposition

4. What makes a species invasive? • c) Environmental <Global> Change Hypothesis • Global Changes • Increasing atmospheric CO2 Keeling & Whorf (2004) CDIAC

5. What makes a species invasive? • c) Environmental <Global> Change Hypothesis • Global Changes • Increasing atmospheric CO2 has 2 direct effects on plants: • Increases photosynthesis → more C for growth Keeling & Whorf (2004) CDIAC

6. What makes a species invasive? • c) Environmental <Global> Change Hypothesis • Global Changes • Increasing atmospheric CO2 has 2 direct effects on plants: • Increases photosynthesis → more C for growth • Closes leaf stomates → uses less water Keeling & Whorf (2004) CDIAC

7. What makes a species invasive? • c) Environmental <Global> Change Hypothesis • Global Changes • Increasing atmospheric CO2 has 2 direct effects on plants: • Increases photosynthesis → more C for growth • Closes leaf stomates → uses less water • Recall C fixation physiology: • C3 pathway: photorespiration wastes ATP (enzyme acts on O2 not just CO2) ; stomata must be open to maintain high enough [CO2] • C4: ‘pumps’ CO2 into bundle sheath cells for fixation, maintains high [CO2] with smaller stomatal openings and less photorespiration • CAM: CO2 fixed in the dark, so stomata open at night (less water loss) • Hypothesis: C3 benefit more from elevated [CO2]

8. What makes a species invasive? • c) Environmental <Global> Change Hypothesis Global Changes – Increasing atmospheric CO2 From Dukes in Mooney & Hobbs (2000) – Table 5.1: Stimulation of growth for invasive species by elevated atmospheric CO2

11. What makes a species invasive? • c) Environmental <Global> Change Hypothesis Global Changes – Increasing atmospheric CO2 From Smith et al. (2000): Red brome (Bromus madritensis ssp. rubens)

12. What makes a species invasive? • c) Environmental <Global> Change Hypothesis Global Changes – Increasing atmospheric CO2 From Belote et al. (2003) New Phytologist 161:827-835 – C4 invasive annual grass & C3 invasive woody vine in sweet gum forest 2001 = wet year

13. What makes a species invasive? • c) Environmental <Global> Change Hypothesis Global Changes – Increasing atmospheric CO2 From Belote et al. (2003) New Phytologist 161:827-835 – C4 invasive annual grass & C3 invasive woody vine in sweet gum forest 2001 = wet year <

14. What makes a species invasive? • c) Environmental <Global> Change Hypothesis Global Changes – Increasing atmospheric CO2 From Belote et al. (2003) New Phytologist 161:827-835 – C4 invasive annual grass & C3 invasive woody vine in sweet gum forest 2001 = wet year > <

15. What makes a species invasive? • c) Environmental <Global> Change Hypothesis Global Changes – Increasing atmospheric CO2 From Belote et al. (2003) New Phytologist 161:827-835 – C4 invasive annual grass & C3 invasive woody vine in sweet gum forest 2001 = wet year  > <

16. What makes a species invasive? • c) Environmental <Global> Change Hypothesis Global Changes – Increasing atmospheric CO2 From Belote et al. (2003) New Phytologist 161:827-835 – C4 invasive annual grass & C3 invasive woody vine in sweet gum forest 2001 = wet year  > < 2002 = dry year <  <

17. What makes a species invasive? • c) Environmental <Global> Change Hypothesis Global Changes – Increasing atmospheric CO2 From Dukes in Mooney & Hobbs (2000) – Fig. 5.1: Stimulation of growth by elevated CO2 for invasives vs. non-invasives

18. What makes a species invasive? • c) Environmental <Global> Change Hypothesis • Global Changes • Increasing atmospheric CO2 • Evidence in some specific cases • But not all invasives benefit • Perhaps fast-growing and N-fixing species respond most • Mediated by other resources (nutrients, water)

19. What makes a species invasive? • c) Environmental <Global> Change Hypothesis • Global Changes • Increased temperatures

22. What makes a species invasive? • c) Environmental <Global> Change Hypothesis • Global Changes • Increased temperatures: • Loebl et al (2006): Spartina anglica (exotic sea grass) spread increased with warmer water temperatures in California • Cheatgrass: • Spring annual in cold climates • Fall-germinating, winter annual in warmer climates • Fall germinating plants more robust and produce more seeds

23. What makes a species invasive? • c) Environmental <Global> Change Hypothesis • Global Change Factors • Precipitation changes

26. What makes a species invasive? • c) Environmental <Global> Change Hypothesis • Global Change Factors • Precipitation changes • Change in timing, size of precip events • ‘pulses’ are important especially in arid ecosystems • If a ‘pulse’ not used up immediately, could another species invade?

27. What makes a species invasive? • c) Environmental <Global> Change Hypothesis • Global Change Factors • N deposition (by-product of human activity, fuels etc) • Invasives may be ‘nitrophilous’ and invade enriched areas • Evidence both ways: • Vinton and Goergin (2006) Ecosystems 9:967-976: Bromus inermis in N. Am. Central grasslands - increased growth under enriched N; reduced growth under reduced N. Natives less effect of enrichment. • Thomsen et al (2006) Plant Ecology 186:23-35: elevated soil N from nitrogen fixing shrubs did not affect competition between native and exotic perennial grasses in CA coastal prarie • Restoration may involve addition of carbon to soils

28. What makes a species invasive? • c) Environmental <Global> Change Hypothesis • Global Change Factors • Increasing atmospheric CO2 • Increasing N deposition • Global warming • SUMMARY:Global Changes • General response is similar to that observed for elevated CO2 • Evidence in some specific cases • But not all invasives benefit • Precipitation changes and N deposition hypotheses relate to the ‘resource abundance’ hypothesis (next week)