Mauna Loa
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
Atm
osph
eric
[C
O2]
(pp
mv)
300
320
340
360
380
400
3) What makes a species invasive?b) Environmental <Global> Change Hypothesis
Global Changes• Increasing atmospheric CO2
Keeling & Whorf (2004) CDIAC
3) What makes a species invasive?b) Environmental <Global> Change Hypothesis
Global Changes• Increasing atmospheric CO2
3) What makes a species invasive?b) Environmental <Global> Change Hypothesis
Global Changes• Increasing atmospheric CO2 has 2 direct effects on plants:
Increases photosynthesis → more C for growth
CO2
Photosynthesis:6CO2 + 6H2O + light C6H1206 + 6O2 + energy
3) What makes a species invasive?b) Environmental <Global> Change Hypothesis
Global Changes• Increasing atmospheric CO2 has 2 direct effects on plants:
Increases photosynthesis → more C for growthCloses leaf stomates → uses less water
H2OCO2
Photosynthesis:6CO2 + 6H2O + light C6H1206 + 6O2 + energy
3) What makes a species invasive?b) Environmental <Global> Change Hypothesis
Global Changes• Increasing atmospheric CO2 has 2 direct effects on plants:
Increases photosynthesis → more C for growthCloses leaf stomates → uses less water
• Not all species react the same:C3 plants – responsive to CO2; high stomatal opening
H2OCO2
Photosynthesis:6CO2 + 6H2O + light C6H1206 + 6O2 + energy
3) What makes a species invasive?b) Environmental <Global> Change Hypothesis
Global Changes• Increasing atmospheric CO2 has 2 direct effects on plants:
Increases photosynthesis → more C for growthCloses leaf stomates → uses less water
• Not all species react the same:C3 plants – responsive to CO2; high stomatal openingC4 plants – CO2 concentrating mechanism; small stomatal opening
3) What makes a species invasive?b) Environmental <Global> Change Hypothesis
Global Changes• Increasing atmospheric CO2 has 2 direct effects on plants:
Increases photosynthesis → more C for growthCloses leaf stomates → uses less water
• Not all species react the sameC3 plants – responsive to CO2; high stomatal openingC4 plants – CO2 concentrating mechanism; small stomatal openingCAM plants – CO2 fixed at night & stored; stomata open at night
3) What makes a species invasive?b) Environmental <Global> Change Hypothesis
Global Changes• Increasing atmospheric CO2 has 2 direct effects on plants:
Increases photosynthesis → more C for growthCloses leaf stomates → uses less water
• Not all species react the sameC3 plants – responsive to CO2; high stomatal openingC4 plants – CO2 concentrating mechanism; small stomatal openingCAM plants – CO2 fixed at night & stored; stomata open at night
H2OCO2
Photosynthesis:6CO2 + 6H2O + light C6H1206 + 6O2 + energy
3) What makes a species invasive?b) 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
3) What makes a species invasive?b) Environmental <Global> Change Hypothesis
Global Changes – Increasing atmospheric CO2
From Belote et al. (2003) New Phytologist 161:827-835 – Oak Ridge Free Air CO2 Enrichment (FACE) experiment in sweet gum forest
3) What makes a species invasive?b) 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
3) What makes a species invasive?b) 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
<
3) What makes a species invasive?b) 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
<
>
3) What makes a species invasive?b) 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
<
>
3) What makes a species invasive?b) 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
<
3) What makes a species invasive?b) 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
<
3) What makes a species invasive?b) 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
<
<
3) What makes a species invasive?b) Environmental <Global> Change Hypothesis
Global Changes – Increasing atmospheric CO2
From Smith et al. (2000): Nevada Desert FACE Facility
3) What makes a species invasive?b) Environmental <Global> Change Hypothesis
Global Changes – Increasing atmospheric CO2
From Smith et al. (2000): Red brome (Bromus madritensis ssp. rubens)
3) What makes a species invasive?b) 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. noninvasives
3) What makes a species invasive?b) Environmental <Global> Change Hypothesis
Global Changes• Increasing atmospheric CO2
Evidence in some specific casesBut not all invasives benefit
3) What makes a species invasive?b) Environmental <Global> Change Hypothesis
Global Changes• Increasing atmospheric CO2
• Global warming
3) What makes a species invasive?b) Environmental <Global> Change Hypothesis
Global Changes• Increasing atmospheric CO2
• Global warming• Increasing N deposition
3) What makes a species invasive?b) Environmental <Global> Change Hypothesis
Global Changes• Increasing atmospheric CO2
• Global warming• Increasing N deposition
SUMMARY: Global Changes• General response is similar to that observed for elevated CO2
Evidence in some specific casesBut not all invasives benefit