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Grassland Soil and Water Research Laboratory
The web address to this site is
http://www.ars.usda.gov/spa/gswrl/wpolley

Education
University of Oklahoma
M.S. Botany 1983
Colorado State University
Ph.D. Range Science 1987
Current Projects and Research
A prevailing goal of my research is to provide insight into how the productivity
and species composition of
rangelandvegetation will respond to rising atmospheric carbon dioxide (CO
2) concentration. Atmospheric CO
2has increased about 30% since industrialization and perhaps 100% since
the last Ice Age to the current 360 ppm (parts per million). It is expected
to approximately double during the next century. Atmospheric CO
2is required by plants to grow. It can also modify plant requirements for
and use of other essential resources, like water and nitrogen, with consequences
for hydrology, nitrogen cycling, and species composition on rangelands.
Research to date has focused on the physiological responses of plants
to higher CO
2concentration. I have studied leaf- and canopy-level photosynthesis, transpiration,
and respiration in a variety of plants, and fixation of atmospheric nitrogen
(N
2) by woody legumes. Possible effects of the past rise in atmospheric CO
2have been studied in a unique,
elongated growth chamberalong which plants are exposed to a continuous gradient in CO
2from low concentrations representative of the last Ice Age to the present
level. Controlled-environment greenhouses have been used to study effects
of predicted increases in CO
2concentration on plant growth and use of water and nitrogen.
I am currently interested in evaluating effects of rising CO
2concentration on the water economy of rangeland plants, since water availability
is among most important regulators of plant productivity and species composition
in these ecosystems. Areas of interest include effects of atmospheric CO
2on plant water use efficiency (production per unit of transpiration),
total transpiration or water use, and response to drought.
These and other questions are being studied in novel elongated chambers
situated on grassland in central Texas
(Prairie CO
2Gradient, PCG). A continuous and uniform gradient in CO
2from near the Ice Age concentration (200 ppm) to the current 360 ppm and
from the current concentration to one predicted for the next century (550
ppm) has been applied to the grassland for two years. This is the first
field site exposed to low CO
2concentrations representative of Earth's atmosphere for the last 200,000
years or more. With cooperators, I will assess effects of past and projected
increases in atmospheric CO
2concentration on the carbon balance, water dynamics, and species composition
of this ecosystem.
Recent Publications
- Isbell, F.I., H.W. Polley and B.J. Wilsey. 2009. Species interaction mechanisms
maintain grassland plant species diversity. Ecology 90:1821-1830.
Publication
- Isbell, F.I., H.W. Polley and B.J. Wilsey. 2009. Biodiversity, productivity
and the temporal stability of productivity: patterns and processes. Ecology
Letters 12:443-451.
Publication
- Wilkinson, M.J., R.K. Monson, N. Trahan, S. Lee, E. Brown, R.B. Jackson,
H.W. Polley, P.A. Fay and R. Fall. 2009. Leaf isoprene emission rate as
a function of atmospheric CO
2concentration. Global Change Biology 15:1189-1200.
Publication
- Wilsey, B.J., T.B. Teaschner, P.P. Daneshgar, F.I. Isbell and H.W. Polley.
2009. Biodiversity maintenance mechanisms differ between native and novel
exotic-dominated communities. Ecology Letters 12:432-442.
Publication
- Polley, H.W., A.B. Frank, J. Sanabria, and R.C. Phillips. 2008. Interannual
variability in carbon dioxide fluxes and flux-climate relationships on
grazed and ungrazed northern mixed-grass prairie. Global Change Biology
14: 1620-1632. pdf available on request.
- Polley, H.W., H.B. Johnson, P.A. Fay, and J. Sanabria. 2008. Initial response
of evapotranspiration from tallgrass prairie vegetation to CO2 at subambient
to elevated concentrations. Functional Ecology 22: 163-171. pdf available
on request.
- Polley, H.W., B.J. Wilsey, and J.D. Derner. 2007. Dominant species constrain
effects of species diversity on temporal variability in biomass production
of tallgrass prairie. Oikos 116: 2044-2052.
Publication
- Polley, H.W., B. J. Wilsey, and C.R. Tischler. 2007. Species abundances
influence the net biodiversity effect in mixtures of two plant species.
Basic and Applied Ecology. 8: 209-218.
Publication
- Polley, H.W., W.A. Dugas, P.C. Mielnick, and H.B. Johnson. 2007. C3-C4
composition and prior carbon dioxide treatment regulate the response of
grassland carbon and water fluxes to carbon dioxide. Functional Ecology
21: 11-18. pdf available on request.
- Wilsey, B.J. and H.W. Polley. 2006. Aboveground productivity and root-shoot
allocation differ between native and introduced grass species. Oecologia
150: 300-309.
Publication
- Polley, H.W., P.C. Mielnick, W.A. Dugas, H.B. Johnson, and J. Sanabria.
2006. Increasing CO
2from subambient to elevated concentrations increases grassland respiration
per unit of net carbon fixation. Global Change Biology 12: 1390-1399.
Publication
- Polley, H.W., B.J. Wilsey, J.D. Derner, H.B. Johnson, and J. Sanabria.
2006. Early-successional plants regulate grassland productivity and species
composition: a removal experiment. Oikos 113: 287-295.
Publication
- Polley, H.W., C.R. Tischler, and H.B. Johnson. 2006. Elevated atmospheric
CO
2magnifies intra-specific variation in seedling growth of honey mesquite:
An assessment of relative growth rates. Rangeland Ecology and Management
59: 128-134.
Publication
- Gill, R.A., L.J. Anderson, H.W. Polley, H.B. Johnson, and R.B. Jackson.
2006. Potential nitrogen constraints on soil carbon sequestration under
low and elevated atmospheric CO
2.
Ecology 87: 41-52.
Publication
- Wilsey, B.J., L.M. Martin, and H.W. Polley. 2005. Predicting plant extinction
based on species-area curves in prairie fragments with high beta richness.
Conservation Biology 19: 1835-1841.
Publication
- Derner, J.D., G.E. Schuman, M. Jawson, S.R. Shafer, J.A. Morgan, H.W.
Polley, G.B. Runion, S.A. Prior, H.A. Torbert, H.H. Rogers, J. Bunce, L.
Ziska, J.W. White, A.J. Franzluebbers, J.D. Reeder, R.T. Venterea, and
L.A. Harper. 2005. USDA-ARS global change research on rangelands and pasturelands.
Rangelands 27(5): 36-42.
Publication
- Polley, H.W., J.D. Derner, and B.J. Wilsey. 2005. Patterns of plant species
diversity in remnant and restored tallgrass prairies. Restoration Ecology
13: 480-487.
Publication
- Derner, J.D., C.R. Tischler, H.W. Polley and H.B. Johnson. 2005. Seedling
growth of two honey mesquite varieties under CO
2enrichment. Rangeland Ecology & Management 58: 292-298.
Publication
- Wilsey, B.J. and H.W. Polley. 2004. Realistically low species evenness
does not alter grassland species-richness-productivity relationships. Ecology
85:2693-2700.
Publication
- Derner, J.D., H.W. Polley, H.B. Johnson, and C.R. Tischler. 2004. Structural
attributes of Schizachyrium scoparium in restored Texas blackland prairies.
Restoration Ecology 12:80-84.
Publication
- Derner, J.D., C.R. Tischler, H.W. Polley, and H.B. Johnson. 2004. Intergenerational
above- and belowground responses of spring wheat (Triticum aestivum L.)
to elevated CO
2. Basic and Applied Ecology 5:145-152.
Publication
- Morgan, J.A., D.E. Pataki, C. Körner, H. Clark, S.J. Del Grosso, J.M.
Grünzweig, A.K. Knapp, A.R. Mosier, P.C.D. Newton, P.A. Niklaus, J.B. Nippert,
R.S. Nowak, W.J. Parton, H.W. Polley, and M.R. Shaw. 2004. Water relations
in grassland and desert ecosystems exposed to elevated atmospheric CO
2. Oecologia 140:11-25.
Publication
- Derner, J.D., H.B. Johnson, B.A. Kimball, P.J. Pinter, Jr., H.W. Polley,
C.R. Tischler, T.W. Boutton, R.L. LaMorte, G.W. Wall, N.R. Adam, S.W. Leavitt,
M.J. Ottman, A.D. Matthias and T.J. Brooks. 2003. Above- and belowground
responses of C3-C4 species mixtures to elevated CO
2and soil water availability. Global Change Biology 9:452-460.
Publication
- Polley, H.W., H.B. Johnson and J.D. Derner. 2003. Increasing CO
2from subambient to superambient concentrations alters species composition
and increases above-ground biomass in a C3/C4 grassland. New Phytologist
160:319-327.
Publication
- Polley, H.W., B.J. Wilsey and J.D. Derner. 2003. Do species evenness and
plant density influence the magnitude of selection and complementarity
effects in annual plant species mixture? Ecology Letters 6:248-256.
Publication
- Wilsey, B.J. and H.W. Polley. 2003. Effects of seed additions and grazing
history on species diversity and aboveground productivity of sub-humid
grasslands. Ecology 84: 920-931.
Publication
- Gill, R.A., H.W. Polley, H.B. Johnson, L.J. Anderson, H. Maherali and
R.B. Jackson. 2002. Nonlinear grassland responses to past and future atmospheric
CO
2. Nature 417:279-282.
Publication
- Maherali, H., C.D. Reid, H.W. Polley, H.B. Johnson and R.B. Jackson. 2002.
Stomatal acclimation over a subambient to elevated CO
2gradient in a C3/C4 grassland. Plant, Cell and Environment 25:557-566.
Publication
- Polley, H.W. 2002. Implications of atmospheric and climatic change for
crop yield and water use efficiency. Crop Science 42:131-140.
Publication
- Polley, H.W., H.B. Johnson and J.D. Derner. 2002. Soil- and plant-water
dynamics in a C3/C4 grassland exposed to a subambient to superambient CO
2gradient. Global Change Biology 8:1118-1129.
Publication
- Polley, H.W., H.B. Johnson and C.R. Tischler. 2002. Woody invasion of
grasslands: evidence that CO
2enrichment indirectly promotes establishment of Prosopis glandulosa. Plant
Ecology 164:85-94.
Publication
- Polley, H.W., C.R. Tischler, H.B. Johnson and J.D. Derner. 2002. Growth
rate and survivorship of drought: CO
2effects on the presumed tradeoff in seedlings of five woody legumes. Tree
Physiology 22:383-391.
Publication
- Wilsey, B.J. and H.W. Polley. 2002. Reductions in grassland species evenness
increase dicot seedling invasion and spittle bug infestation. Ecology Letters
5:676-684.
Publication
- Anderson, L.J., H. Maherali, H.B. Johnson, H.W. Polley and R.B. Jackson.
2001. Gas exchange and photosynthetic acclimation over subambient to elevated
CO
2in a C3-C4 grassland. Global Change Biology 7:693-707.
Publication
- Dugas, W.A., H.W. Polley, H.S. Mayeux, and H.B. Johnson. 2001. Acclimation
of whole-plant Acacia farnesiana transpiration to carbon dioxide concentration.
Tree Physiology 21:771-773.
Publication
- Mielnick, P.C., W.A. Dugas, H.B. Johnson, H.W. Polley and J. Sanabria.
2001. Net grassland carbon flux over a subambient to superambient CO
2gradient. Global Change Biology 7:747-754.
Publication
- Derner, J.D., H.W. Polley, H.B. Johnson, and C.R. Tischler. 2001. Root
system response of C
4grass seedlings to CO
2and soil water. Plant and Soil 231:97-104.
Publication
- Johnson, H.B., H.W. Polley, and R.P. Whitis. 2000. Elongated chambers
for field studies across atmospheric CO
2gradients. Functional Ecology 14:388-396.
Publication
- Polley, H.W., J.A. Morgan, B.D. Campbell, and Mark Stafford Smith. 2000.
Crop ecosystem responses to climatic change: rangelands, pp. 293-314. In:
Reddy, K.R. and Hodges, H.F. (eds.) Climate Change and Global Crop Productivity.
CABI Publishing, Wallingford, U.K.
Publication
- Tischler, C.R., H.W. Polley, H.B. Johnson, and R.E. Pennington. 2000.
Seedling response to elevated CO
2in five epigeal species. International Journal of Plant Sciences 161:779-783.
Publication
- Pennington, R.E., C.R. Tischler, H.B. Johnson, and H.W. Polley. 1999.
Genetic variation for carbon isotope composition in honey mesquite (Prosopis
glandulosa). Tree Physiology 19:583-589.
Publication
- Polley, H.W., H.B. Johnson, C.R. Tischler, and H.A. Torbert. 1999. Links
between transpiration and plant nitrogen: variation with atmospheric CO
2concentration and nitrogen availability. International Journal of Plant
Sciences 160:535-542.
Publication
- Polley, H.W., C.R.Tischler, H.B. Johnson, and R.E. Pennington. 1999. Growth,
water relations, and survival of drought-exposed seedlings from six maternal
families of honey mesquite (Prosopis glandulosa): responses to CO
2enrichment. Tree Physiology 19:359-366.
Publication
- Tischler, C.R., H.W. Polley, H.B. Johnson, and H.S. Mayeux. 1998. Environment
and seedling age influence mesquite response to epicotyl removal. Journal
of Range Management 51(3):361-365.
Publication
- Mayeux, H.S., H.B.Johnson, H.W. Polley, and S.R. Malone. 1997. Yield of
wheat across a subambient carbon dioxide gradient. Global Change Biology
3:269-278.
Publication
- Polley, H.W. 1997. Invited synthesis paper: Implications of rising atmospheric
carbon dioxide concentration for rangelands. Journal of Range Management
50:562-577.
Publication
- Polley, H.W., H.S. Mayeux, H.B. Johnson, and C.R. Tischler. 1997. Viewpoint:
Atmospheric CO
2soil water, and shrub/grass ratios on rangelands. Journal of Range Management
50:278-284.
Publication
- Polley, H.W., H.B. Johnson, and H.S. Mayeux. 1997. Leaf physiology, production,
water use, and nitrogen dynamics of the grassland invader Acacia smallii
at elevated CO
2concentrations. Tree Physiology 17: 89-96.
Publication
- Polley, H.W., H.B. Johnson, H.S. Mayeux, D.A. Brown, and J.W.C. White.
1996. Leaf and plant water use efficiency of C
4species grown at glacial to elevated CO
2concentrations. International Journal of Plant Sciences 157: 164-170.
Publication
- Polley, H.W., H.B. Johnson, H.S. Mayeux, and C.R. Tischler, C.R. 1996.
Are some of the recent changes in grassland communities a response to rising
CO
2concentrations?, pp. 177-195. In: Korner, Ch. and F.A. Bazzaz (eds.) Carbon
Dioxide, Populations, and Communities. Academic Press. San Diego, California.
Publication
- Polley, H.W., H.B. Johnson, H.S. Mayeux, and C.R. Tischler. 1996. Impacts
of rising CO
2concentration on water use efficiency of woody grassland invaders, pp.
189-194. In: Barrow, J R., E.D. McArthur, R.E. Sosebee, and R.J. Tausch.
(comps.) Proceedings: Symposium on Shrubland Ecosystem Dynamics in a Changing
Climate. Intermountain Res. Sta., U.S.D.A., Forest Service, Gen. Tech.
Rep., Ogden, UT.
Publication
- Polley, H.W., H.B. Johnson, H.S. Mayeux, C.R. Tischler, and D.A. Brown.
1996. Carbon dioxide enrichment improves growth, water relations and survival
of droughted honey mesquite (Prosopis glandulosa) seedlings. Tree Physiology
16:817-823.
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