climate change information: uk hadley centre
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Climate change information: UK Hadley Centre. http://www.metoffice.gov.uk/research/hadleycentre/. What makes a species invasive? c) Environmental Change Hypothesis. Global Changes Increasing atmospheric CO 2 Changes in temperature Changes in precipitation Nitrogen deposition. - PowerPoint PPT PresentationTRANSCRIPT
Climate change information: UK Hadley Centre
http://www.metoffice.gov.uk/research/hadleycentre/
3) What makes a species invasive?c) Environmental <Global> Change Hypothesis
Global Changes• Increasing atmospheric CO2
• Changes in temperature• Changes in precipitation• Nitrogen deposition
Mauna Loa
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
Atm
osph
eric
[CO
2] (p
pmv)
300
320
340
360
380
400
3) What makes a species invasive?c) Environmental <Global> Change Hypothesis
Global Changes• Increasing atmospheric CO2
Keeling & Whorf (2004) CDIAC
Mauna Loa
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
Atm
osph
eric
[CO
2] (p
pmv)
300
320
340
360
380
400
3) 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
Mauna Loa
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005
Atm
osph
eric
[CO
2] (p
pmv)
300
320
340
360
380
400
3) 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 growthCloses leaf stomates → uses less water
Keeling & Whorf (2004) CDIAC
3) 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 growthCloses 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]
3) 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
group Estimate
C3herb 1.6171 A
C3woody 1.5576 A
C4 1.0200 B
3) 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)
3) 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
3) 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
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3) 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
<
>
3) 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
<
>
3) 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
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>
2002 = dry year
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3) 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
3) What makes a species invasive?c) Environmental <Global> Change Hypothesis
Global Changes• Increasing atmospheric CO2
Evidence in some specific casesBut not all invasives benefitPerhaps fast-growing and N-fixing species respond mostMediated by other resources (nutrients, water)
3) What makes a species invasive?c) Environmental <Global> Change Hypothesis
Global Changes• Increased temperatures
3) 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
3) What makes a species invasive?c) Environmental <Global> Change Hypothesis
Global Change Factors• Precipitation changes
3) 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?
3) 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
3) 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 casesBut not all invasives benefit
• Precipitation changes and N deposition hypotheses relate to the ‘resource abundance’ hypothesis (next week)