3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes Increasing atmospheric CO 2 Keeling & Whorf (2004) CDIAC

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes Increasing atmospheric CO 2

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes Increasing atmospheric CO 2 has 2 direct effects on plants: Increases photosynthesis → more C for growth CO 2 Photosynthesis: 6CO 2 + 6H 2 O + light  C 6 H O 2 + energy

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes Increasing atmospheric CO 2 has 2 direct effects on plants: Increases photosynthesis → more C for growth Closes leaf stomates → uses less water H2OH2O CO 2 Photosynthesis: 6CO 2 + 6H 2 O + light  C 6 H O 2 + energy

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes Increasing atmospheric CO 2 has 2 direct effects on plants: Increases photosynthesis → more C for growth Closes leaf stomates → uses less water Not all species react the same: C 3 plants – responsive to CO 2 ; high stomatal opening H2OH2O CO 2 Photosynthesis: 6CO 2 + 6H 2 O + light  C 6 H O 2 + energy

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes Increasing atmospheric CO 2 has 2 direct effects on plants: Increases photosynthesis → more C for growth Closes leaf stomates → uses less water Not all species react the same: C 3 plants – responsive to CO 2 ; high stomatal opening C 4 plants – CO 2 concentrating mechanism; small stomatal opening

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes Increasing atmospheric CO 2 has 2 direct effects on plants: Increases photosynthesis → more C for growth Closes leaf stomates → uses less water Not all species react the same C 3 plants – responsive to CO 2 ; high stomatal opening C 4 plants – CO 2 concentrating mechanism; small stomatal opening CAM plants – CO 2 fixed at night & stored; stomata open at night

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes Increasing atmospheric CO 2 has 2 direct effects on plants: Increases photosynthesis → more C for growth Closes leaf stomates → uses less water Not all species react the same C 3 plants – responsive to CO 2 ; high stomatal opening C 4 plants – CO 2 concentrating mechanism; small stomatal opening CAM plants – CO 2 fixed at night & stored; stomata open at night H2OH2O CO 2 Photosynthesis: 6CO 2 + 6H 2 O + light  C 6 H O 2 + energy

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes – Increasing atmospheric CO 2 From Dukes in Mooney & Hobbs (2000) – Table 5.1: Stimulation of growth for invasive species by elevated atmospheric CO 2

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes – Increasing atmospheric CO 2 From Belote et al. (2003) New Phytologist 161: – Oak Ridge Free Air CO 2 Enrichment (FACE) experiment in sweet gum forest

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes – Increasing atmospheric CO 2 From Belote et al. (2003) New Phytologist 161: – C 4 invasive annual grass & C 3 invasive woody vine in sweet gum forest 2001 = wet year

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes – Increasing atmospheric CO 2 From Belote et al. (2003) New Phytologist 161: – C 4 invasive annual grass & C 3 invasive woody vine in sweet gum forest 2001 = wet year <

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes – Increasing atmospheric CO 2 From Belote et al. (2003) New Phytologist 161: – C 4 invasive annual grass & C 3 invasive woody vine in sweet gum forest 2001 = wet year < >

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes – Increasing atmospheric CO 2 From Belote et al. (2003) New Phytologist 161: – C 4 invasive annual grass & C 3 invasive woody vine in sweet gum forest 2001 = wet year < > 

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes – Increasing atmospheric CO 2 From Belote et al. (2003) New Phytologist 161: – C 4 invasive annual grass & C 3 invasive woody vine in sweet gum forest 2001 = wet year < >  2002 = dry year <

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes – Increasing atmospheric CO 2 From Belote et al. (2003) New Phytologist 161: – C 4 invasive annual grass & C 3 invasive woody vine in sweet gum forest 2001 = wet year < >  2002 = dry year < 

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes – Increasing atmospheric CO 2 From Belote et al. (2003) New Phytologist 161: – C 4 invasive annual grass & C 3 invasive woody vine in sweet gum forest 2001 = wet year < >  2002 = dry year < < 

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes – Increasing atmospheric CO 2 From Smith et al. (2000): Nevada Desert FACE Facility

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes – Increasing atmospheric CO 2 From Smith et al. (2000): Red brome (Bromus madritensis ssp. rubens)

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes – Increasing atmospheric CO 2 From Dukes in Mooney & Hobbs (2000) – Fig. 5.1: Stimulation of growth by elevated CO 2 for invasives vs. noninvasives

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes Increasing atmospheric CO 2 Evidence in some specific cases But not all invasives benefit

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes Increasing atmospheric CO 2 Global warming

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes Increasing atmospheric CO 2 Global warming Increasing N deposition

3)What makes a species invasive? b) Environmental Change Hypothesis Global Changes Increasing atmospheric CO 2 Global warming Increasing N deposition SUMMARY: Global Changes General response is similar to that observed for elevated CO 2 Evidence in some specific cases But not all invasives benefit