Sasha Reed

I am a scientist with the U.S. Geological Survey and a member of the Southwest Biological Science Center. My research interests are centered within the fields of biogeochemistry and ecosystem ecology. Currently, I study terrestrial ecosystems in Utah, Arizona, New Mexico, California, Colorado, Hawai’i, Puerto Rico, Bolivia, Perú, and Costa Rica. 


Current Research Interests
  • Climate change and its effects on terrestrial ecosystems: Climate change is predicted to significantly alter terrestrial ecosystems around the globe, with the potential to negatively affect a suite of ecosystem services. These changes also have the potential to create feedbacks that could alter the course of future climate change. I have a variety of projects - ranging from climate manipulations in southwestern U.S. drylands and a Puerto Rican tropical wet forest to elevation gradients in Hawai'ian forests - aimed at elucidating how terrestrial ecosystems will respond to climate change. In particular, I am interested in understanding the mechanisms behind observed ecosystem changes, with the overarching goal of not only bettering our understanding these systems, but of improving our predictions of future ecosystem function as well. The ability to span spatial and temporal scales is particularly important, and  I work closely with a number of collaborators in order to try and reach these research goals.
  • Biofuels development in the southwestern U.S.: Alternative energy offers a suite of potential benefits for lowering greenhouse gas emissions, adding to our economy, and reducing our dependence upon foreign oil. In particular, due to high solar energy and newer biofuel crop alternatives, bioenergy development in the southwestern U.S. could represent a significant source of biofuel energy. However, we know little about the potential for this region to act as an efficient biofuel energy source; what resources this development would require (irrigation, fertilization, etc.); what effects it would have on overall greenhouse gas budgets and local plant and animal communities; and what ecosystem consequences might follow from this development. I am currently part of a group conducting a multi-disciplinary assessment of biofuels in the southwestern U.S., integrating modeling efforts with field and laboratory assessments.
  • Invasive species, beetle infestation and ecosystem consequences: Beetles are affecting plant communities across the western U.S., and a relatively recent release of the Tamarisk Beetle (Diorhabda elongata) has caused major Tamarisk (Tamarix spp.) defoliation events along western river corridors. Understanding how this defoliation and likely death of Tamarisk will affect future riparian communities is at the heart of this research. I am part of a multi-Center USGS team working to assess the consequences of defoliation on exotic plant invasion, biogeochemical cycling, hydrology, plant-water interactions, and bird and mammal communities. The central goals are to understand what aspects of defoliation and mortality help determine the trajectory of future community composition and what management approaches might take advantage of this understanding to reduce exotic plant invasion.
  • Nitrogen deposition in the Four Corners Region, USA: Nitrogen deposition in the western U.S. has repeatedly been linked with lowered air quality, increased greenhouse gas emissions, altered plant community composition, reduced water quality, and modified fire regimes. Using modeling and field approaches in Arches, Canyonlands, and Mesa Verde National Parks, I am part of a research team investigating how increased nitrogen deposition in the Four Corners region could affect plant and soil communities and their function. In particular, we are asking questions about how nitrogen deposition could affect exotic plant invasion, the frequency of natural fire regimes, soil stability, greenhous gas emissions, water and air quality, and feedbacks between nitrogen deposition and multiple other aspects of terrestrial biogeochemical cycling.



Ph.D. in Ecology, University of Colorado at Boulder (August 2002-May 2008)

Department of Ecology & Evolutionary Biology and Institute of Arctic & Alpine Research (INSTAAR), Boulder, CO.

Co-advised by Alan R. Townsend and Steve K. Schmidt.


B.A. in Organic Chemistry, Colgate University (August 1993-May 1997)

Department of Chemistry, Hamilton, NY. Graduated magna cum laude.

Advised by David A. Modarelli.


Courses Outside My Universities:

CO2 Flux Methods Course led by Drs. Russ Monson, Dave Moore, and Paul Stoy, July 2012.

Dr. Jim Ehleringer’s Isotope Course at The University of Utah, June 2005.

Organization for Tropical Studies (OTS) Tropical Ecology Program, January-March 2003.

NSF Environmental Geology and Environmental Philosophy Internship, Southwest Earth Studies Group, Durango, CO, May1997-August 1997.


Professional Experience

Research Ecologist, USGS, Moab, UT, May 2008-present.

Research Ecologist, USGS-SCEP Program, Moab, UT, 2005-2007 summers only.


Honors and Fellowships

Awardee, Presidential Early Career Award for Scientists and Engineers (PECASE). Highest honor bestowed by the U.S. government on scientists and engineers in the early stages of their research careers. October 2011.

Recipient, Star Awardreceived for outstanding work with the Department of the Interior. October 2010.

Recipient, Graduate Student Research and Creative Works Award, University of Colorado at Boulder. One of two of the University’s graduating Ph.D. students whose dissertation was selected by faculty members from all disciplines as representing outstanding research and creative work. May 2008.

Fellow, USGS Student Career Experience Program (SCEP). Supported in creating a research project to model how soil gas fluxes in dryland ecosystems will vary under altered climate regimes. June-August of 2006 & 2007.

Recipient, Student Policy Award, Ecological Society of America (ESA). Graduate student chosen and funded by ESA to meet with members of Congress regarding national scientific funding. September 2006.

Selected Participant, AAAS Program for Excellence in Science. Nominated by the University of Colorado Vice Chancellor of Research to participate in a program rewarding praiseworthy graduate students working in the life sciences. August 2006.

Fellow, NSF Graduate Research Fellowship. Awarded April 2003; deferred until September 2005-May 2008.

Fellow, NSF IGERT Fellowship, Carbon Climate and Society Initiative (CCSI). August 2003-August 2005.

Selected Full Member, Sigma Xi Scientific Research Society, Fall 2003-Present.

Recipient, Star Awardreceived for outstanding work with the Department of the Interior. May 2000.

Fellow, Wolk Foundationfellowship for promising student research. Summer 1996.

Recipient, Lawrence Award, awarded to one student annually for superior performance in organic chemistry. April 1996.

Selected Member, Phi Ea Sigma University Honor Society, chosen for academic excellence. April 1994-May 1997.

Selected Board Member, Phi Eta Sigma Aid Committee, elected for superior   research to a board that selected student grant applications for funding. September 1995-May 1997.

Nominee, Barry Goldwater Award, nationally nominated by Colgate University foracademic distinction. November 1994.



Tucker, CL, SC Reed. (In Press) Low soil moisture during hot periods drives apparent negative temperature sensitivity of soil respiration in a dryland ecosystem: a multi-model comparison. Biogeochemistry.

Metcalf, JL, ZZ Xu, S Weiss, W Van Treuren, E R Hyde, A Amir, Se Jin Song, S Lax, N Sangwan, P Larsen, D Haarmann, GC Humphrey, G Ackermann, LR Thompson, C Lauber, A Bibat, C Nicholas, MJ Gebert, JF Petrosino, SC Reed, JA Gilbert, AM Lynne, SR Bucheli, DO Carter, R Knight. (2016) Terrestrial mammalian decomposition proceeds by universal rules of microbial assembly and metabolic function. Science 351: 158-162.

Lü, XT, SC Reed, Q Yu, XG Han (2016) Nutrient resorption helps drive intra-specific coupling of foliar nitrogen and phosphorus under nutrient-enriched conditions. Plant and Soil: 311: 111-120.

Smith, WK, SC Reed, C Cleveland, AP Ballantyne, WRL Anderegg, WR Wieder, YY Liu, SW Running (2015) Large divergence of satellite and Earth system model estimates of global terrestrial CO2 fertilization. Nature Climate Change. 6: 306-310.

Darrouzet-Nardi, A, SC Reed, EE Grote, J Belnap (2015). Observations of net soil exchange of CO2 in a dryland show experimental warming increases carbon losses in biocrust soils. Biogeochemistry. 126: 363-378.

Antoninka, A, MA Bowker, SC Reed, K Doherty (2015) Production of greenhousegrown biocrust mosses and associated cyanobacteria to rehabilitate dryland soil function. Resotoration Ecology

Steven, B, CR Kuske, SC Reed, J Belnap (2015) Climate change and physical disturbance result in distinct biological soil crust communities. Applied & Environmental Microbiology. 81: 7448-7459. 

Ferrenberg, S, SC Reed, J, Belnap (2015) Climate change and physical disturbance cause similar community shifts in biological soil crusts. Proceedings of the National Academy of Sciences. 112: 12116-12121. 

Reed, SC, X Yang, PE Thornton (2015) Urgent need for warming experiments in tropical forests. New Phytologist. 208: 324-329. 

McHugh, T, EM Morrissey, SC Reed, BA Hungate, E Schwartz (2015). Water from air: an overlooked source of moisture in arid and semiarid regions. Scientific Reports 5: 13767.

Reed, SC, X Yang, PE Thornton (2015) Incorporating phosphorus cycling into global modeling efforts: A worthwhile, tractable endeavor. New Phytologist-Tansley Insight.

Cavaleri, CA, SC Reed, WK Smith, TE Wood (2015) Urgent need for warming experiments in tropical forests. Global Change Biology 21: 211-2121.

Wertin, T, SC Reed, J Belnap (2015) C3 and C4 plant responses to increased temperatures and altered monsoonal precipitation in a cool desert on the Colorado Plateau, USA. Oecologia 177: 997-1013.

Hiltbrunner, E, R Aerts, T Buhlmann, K Huss-Danell, B Magnusson, DD Myrold, SC Reed, BD Sigurdsson, C Korner (2014) Spatially robust estimates of biological N2 fixation imply substantial human alteration of the tropical nitrogen cycle. Oecologia 176: 11-24.

Sullvian, BW, WK Smith, AR Townsend, MK Nasto, SC Reed, RL Chazdon, CC Cleveland (2014) Spatially robust estimates of biological N2 fixation imply substantial human alteration of the tropical nitrogen cycle. PNAS doi:10.1073/pnas.1320646111.

Sullvian, BW, S Alvarez-Clare, SC Castle, S Porder, SC Reed, L Schreeg, AR Townsend, CC Cleveland (2014) Assessing nutrient limitation in complex forested ecosystems: Alternatives to large-scale fertilization experiments. Ecology 95: 668-681.

Cleveland, CC, SC Reed, AB Keller, DR Nemergut, SP O'Neill, R Ostertag, PM Vitousek (2014) Litter quality versus soil microbial community controls over decomposition: a quantitative analysis. Oecologia 2110: 12733-12737.

Smith, WK, CC Cleveland, SC Reed, SW Running (2013) Agricultural conversion without external water and nutrient inputs reduces terrestrial vegetation productivity. Geophysical Research Letters. 10.1002/2013GL058857.

Cleveland, CC, BZ Houlton, WK Smith, AR Marklein, SC Reed, W Parton, SJ Del Gross, SW Running (2013) Patterns of new versus recycled primary production in the terrestrial biosphere. PNAS. 110: 12733-12737.

Reed, SC, AR Townsend, CC Cleveland (2013) Relationships between phosphorus, molybdenum and free-living nitrogen fixation in tropical rain forests: Results from observational and experimental analyses. Biogeochemistry: Synthesis & Emerging Ideas Section 114: 1-13.

Vitousek, PM, DNL Menge, SC Reed, CC Cleveland (2013) Biological nitrogen fixation: rates, pattern, and ecological controls in terrestrial ecosystems. Philosophical Transactions of the Royal Society B. 368: 20130119.

Lu, X-T, SC Reed, Q Yu, NP He, ZW Wang, XG Han (2013) Convergent responses of nitrogen and phosphorus resorption to nitrogen inputs in a semi-arid grassland. Global Change Biology 19: 2775-2784.

Keville, MP, SC Reed, CC Cleveland (2013) Nitrogen cycling responses to mountain pine beetle disturbance in a high elevation Whitebark Pine ecosystem. PLoS One 8: e65004. doi:10.1371.

Zelikova, TJ, R Hufbauer, SC Reed, T Wertin, C Fetting, J Belnap. (2013) Eco-evolutionary responses of Bromus tectorum to climate change: Implications for biological invasions. Ecology & Evolution 3: 1384-1387.

Keller, AB, SC Reed, AR Townsend, CC Cleveland (2013) Effects of canopy tree species on belowground biogeochemistry in a lowland wet tropical forest. Soil Biology & Biochemistry 58: 61-69.

Wickings, K, AS Grandy, SC Reed, CC Cleveland (2012) The origin of litter chemical complexity during decomposition. Ecology Letters 15: 1180-1188.

Reed, SC, AR Townsend, CC Cleveland, EA Davidson (2012). Stoichiometric patterns in foliar nutrient resorpton across multiple scales. New Phytologist 196: 173-180.

Reed, SC, KK Coe, JP Sparks, DC Housman, TJ Zelikova, J Belnap (2012) Increased precipitation results in rapid moss mortality and altered fertility in a dryland ecosystem. Nature Climate Change 2: 752-755.

Wood, TE, MA Cavaleri, SC Reed (2012) Tropical forest carbon balance in a warmer world: a critical review spanning microbial- to ecosystem-scale processes. Biological Reviews 87: 912-927. 

Reed, SC, T. Wood  & M. Cavaleri (2012) Tropical forests in a warming world. New Phytologist 193: 27-29.

Wertin, TM, SL Phillips, SC Reed, J Belnap (2012) Elevated CO2 did not mitigate the effect of a short-term drought on biological soil crusts. Biology & Fertility of Soils 48: 797-805.

Smith, WK, CC Cleveland, SC Reed, NL Miller, SW Running (2012) Bioenergy potential of the United States constrained by satellite observations and existing productivity. Environmental Science & Technology 46: 3536-3544.

Reed, SC, CC Cleveland, AR Townsend (2011). Functional ecology of free-living nitrogen fixation: a contemporary review. Annual Review for Ecology and Systematics 42: 489-512. 

Reed, SC, PM Vitousek, CC Cleveland (2011) Are patterns in nutrient limitation belowground consistent with those aboveground: Results from a 4 million year chronosequence. Biogeochemistry 106: 323-336.

Cleveland, CC, AR Townsend, P Taylor, MMC Bustamante, G Chuyong, P Grierson, K Harms, B Houlton, A Marklein, W Parton, S Porder, SC Reed, et al. (2011) Relationships among net primary productivity, nutrients and climate in tropical rain forests: A pan-tropical analysis. Ecology Letters 14: 939-947. 

Schmidt SK, CC Cleveland, DR Nemergut, SC Reed, AJ King, P Sowell (2011) Estimating phosphorus availability for microbial growth in an emerging landscape. Geoderma 163: 135-140.

Wickings, K, AS Grandy, SC Reed, CC Cleveland (2011) Management intensity alters decomposition via biological pathways. Biogeochemistry 104: 365-379.

Reed, SC, AR Townsend, PG Taylor, CC Cleveland. (2011) Phosphorus Cycling in Tropical Forests Growing on Highly-Weathered Soils. In: (Buneman EK, A Oberson, E Forssard) Phosphorus In Action—Biological Processes in Soil Phosphorus Cycling. Springer Publishing Co. vol. 26, pp. 339-369.

Cleveland, CC, WR Wieder, SC Reed, AR Townsend (2010) Experimental drought in a wet tropical forest increases soil carbon dioxide losses to the atmosphere. Ecology 91: 2313-2323.

Reed, SC, AR Townsend, DR Nemergut, SK Schmidt, AR Townsend (2010) Scaling from molecules to ecosystems: Exploring controls over free-living nitrogen fixation in terrestrial systems. VDM Publishers, Saarbrucken Germany.

Reed, SC, AR Townsend, CC Cleveland, DR Nemergut (2010) Microbial community shifts influence patterns in tropical forest nitrogen fixation. Oecologia 164: 521-531.

Cleveland, CC, BZ Houlton, C Neill, SC Reed, AR Townsend, YP Wang (2010) Using indirect methods to constrain symbiotic nitrogen fixation rates: A case study from an Amazonian rain forest. Biogeochemistry 99: 1-13.

Sattin SR, CC Cleveland, E Hood, SC Reed, AJ King, MS Robeson, NL Ascarrunz, DR Nemergut (2009) Functional shifts in perhumid, recently-deglaciated soils do not correlate with shifts in soil bacterial community composition. The Journal of Microbiology 47: 673-681.

Costello, EK, SRP Halloy, SC Reed, P Sowell, SK Schmidt (2009) Fumarole-supported islands of biodiversity within a hyper-arid, high-elevation landscape on Socompa Volcano, Puna de Atacama, Andes. Applied & Environmental Microbiology 75: 735-747.

Freeman, KR, MY Pescador, SC Reed, EK Costello, MS Robeson, SK Schmidt (2009) Soil CO2 flux and photoautotrophic community composition in high-elevation, ‘barren’ soil. Environmental Microbiology 11: 674-686. 

Schmidt, SK, SC Reed, DR Nemergut, AS Grandy, CC Cleveland, MN Weintraub, AW Hill, EK Costello, AF Meyer, AM Martin, JC Neff (2008) The earliest stages of primary succession in high-elevation (5000 meters above sea-level), recently deglaciated soils. Proceedings of the Royal Society B: Biological Sciences 275: 2793-2802. 

Reed, SC, CC Cleveland, AR Townsend (2008) Tree species control rates of  free-living nitrogen fixation in a tropical rain forest. Ecology 89: 2924-2934.

Reed, SC, CC Cleveland, AR Townsend (2007) Controls over leaf litter and soil nitrogen fixation in two lowland tropical rain forests. Biotropica 39: 585-592.

Schmidt, SK, EK Costello, DR Nemergut, CC Cleveland, SC Reed, MN Weintraub, AF Meyer, AM Martin (2007) Microbial turnover and seasonal succession drive biogeochemical cycles in the alpine. Ecology 88: 1379-1385.

Reed, SC, TR Seastedt, CM Mann, KN Suding, AR Townsend (2007) Phosphorus fertilization stimulates nitrogen fixation and increases inorganic nitrogen concentrations in a restored prairie. Applied Soil Ecology 36: 238-242.                          

Cleveland, CC, SC Reed, AR Townsend (2006) Nutrient regulation of organic matter decomposition in a tropical rain forest. Ecology 87: 492-503.

Bowker, MA, SC Reed, J Belnap, SL Phillips (2002) Temporal variation in community composition, pigmentation, and Fv/Fm in desert cyanobacterial soil crusts. Microbial Ecology 43: 13-25.

Reed, SC, GJ Capitosti, Z Zhu & DA Modarelli (2001) Photochemical generation and matrix-isolation detection of dimethylvinylidene. Journal of Organic Chemistry 66: 287-291.

Reed, SC, DA Modarelli (1996) Conformational effects on the excited state 1,2-hydrogen migration in alkyldiazomethanes. Tetrahedron Letters 37: 7209-7212.