columnar cacti: sensitive recorders of cam …...columnar cacti: sensitive recorders of cam...
TRANSCRIPT
![Page 1: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/1.jpg)
Columnar cacti: sensitive recorders
of CAM responses
to environmental change
David G. Williams
Departments of Botany and Ecosystem Science and Management,
University of Wyoming
![Page 2: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/2.jpg)
Ensemble of GCMs, assuming moderate (A1B) emissions scenario, predict warming in the Southwest of North America of 4-5°C for summer and 3-4°C for winter by 2100 relative to average temperatures 1971-2000 (NOAA Earth System Research Laboratory )
“Mega-droughts” are common in paleoclimate record
![Page 3: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/3.jpg)
Is the Sonoran Desert
losing its cool?
Weiss & Overpeck 2005
Increase in extreme
minimum temperatures
observed from 1960-2000.
![Page 4: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/4.jpg)
Isotopes record source and process information
From West et al. 2006
![Page 5: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/5.jpg)
Columnar cacti -
the ‘baleen whales’ of
the desert?
Do they record source
and process information?
![Page 6: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/6.jpg)
Columnar cacti are‘foundation’ species
Carnegiea gigantea
saguaro
![Page 7: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/7.jpg)
Cultural significance
![Page 8: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/8.jpg)
Younger
Numerous areoles on a saguaro plant are produced
each year (4-8/yr along each outer rib)
![Page 9: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/9.jpg)
Figure available at calib.qub.ac.uk/CALIBomb/
Data from Reimer, Brown and Reimer, 2004.
F1
4C
Year
Can we date the spines?
![Page 10: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/10.jpg)
Post-bomb radiocarbon in spines
Fraction modern
saguaro #162
![Page 11: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/11.jpg)
Observed growth and
demography Pierson and Turner (1998)
monitored growth of almost
3000 saguaro from 1963 to
1993.
Figure from E. Pierson and R. Turner 1998
![Page 12: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/12.jpg)
English et al., 2007
![Page 13: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/13.jpg)
![Page 14: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/14.jpg)
Water uptake (two-end member mixing)
δtissue* = δrain (frain) + δtissue (1 – frain)
![Page 15: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/15.jpg)
Transpired water
Cactus tissue water
δ1
8O
(‰
)
Fraction of water remaining (f, %)
δ = (1000+δi) f (α-1)-1000
Transpiration -
Rayleigh distillation?
![Page 16: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/16.jpg)
![Page 17: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/17.jpg)
Modeled and observed δ18O of stem water
English et al. 2007
Irrigation withheld
![Page 18: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/18.jpg)
Oxygen isotope composition of spine tissue records
changes in water balance over time
English et al., 2007
![Page 19: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/19.jpg)
4.4 -5.7
Stomatal closure or Increased carboxylation demand
Winter & Holtum 2002
Strong
CAM
Carbon isotope discrimination
in ‘strong’ CAM plants
![Page 20: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/20.jpg)
![Page 21: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/21.jpg)
English et al., 2010
![Page 22: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/22.jpg)
D =
English et al., 2010
Minimum annual d13C is negatively correlated total annual
precipitation and average nighttime VPD
![Page 23: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/23.jpg)
d18O and d13C of spine biomass are
positively correlated
![Page 24: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/24.jpg)
On-line carbon isotope discrimination measurements
![Page 25: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/25.jpg)
Modeled and observed D13C differ
![Page 26: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/26.jpg)
Anet (mmol CO2 m-2 s-1)
Do
bs –
Di (‰)
Photosynthetic rate influences discrimination
![Page 27: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/27.jpg)
Response to temperature
and drought stressors
Stem volume to
surface area ratio
(V:S) varies by over
an order of
magnitude in
columnar cacti Pachycereus schotii Pachycereus pringlei Cylindropuntia leptocaulis
Tradeoff between growth and storage?
![Page 28: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/28.jpg)
36
38
40
42
44
46
48
50
52
54
56
Sp
ine d
18O
VS
MO
W
High V:S
Low V:SDry
Year
Wet
Year
0
5
10
15
20
25
30
35
0 20 40 60 80 100
water loss (%)
d1
8O
(V
SM
OW
)
High V:S
Low V:S
Low V:S
High V:S Rayleigh distillation curves
![Page 29: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/29.jpg)
Approach
Examine trait correlations
across a broad range of
taxa that vary in V:S
> 40 columnar cacti spp
(+ Cylindropuntia)
Monitor growth and isotopic
composition of multiple columnar
cacti across a broad climate
gradient
Experiments
exposing plants
of different V:S
to carefully
controlled stress
conditions
![Page 30: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/30.jpg)
Hydrogen isotope ratio of spine biomass is positively correlated to V:S
![Page 31: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/31.jpg)
Conclusions Rapid and dramatic climate change has happened, is happening and will happen in regions supporting high CAM biodiversity Sub-annual to decadal variation in physiology and metabolism of columnar cacti are recorded in the stable isotope composition of spines We now are poised to examine responses of a range of columnar cacti to climate variation using, experiment, field monitoring and isotopic analysis Functional tradeoffs among key traits in CAM stem succulents may underlie responses to extreme mega-droughts anticipated for subtropical desert regions
![Page 32: Columnar cacti: sensitive recorders of CAM …...Columnar cacti: sensitive recorders of CAM responses to environmental change David G. Williams Departments of Botany and Ecosystem](https://reader036.vdocument.in/reader036/viewer/2022062603/5f14d8c66c8abe5837426a38/html5/thumbnails/32.jpg)
Enrico Yepez, ITSON, Mexico
Darren Sandquist, Cal State Fullerton
Dustin Bronson, Wisconsin DNR
Kevin Hultine & Raul Puente-Martinez, Desert Botanical Garden, Phoenix
David Dettman, U. Arizona Nathan English, James Cook University