James F. Reynolds
Professor of Environmental Sciences and Biology

919-660-7404, 919-660-7405

110 Phytotron

Reynolds NSEE Page

Research Interests: Land degradation in arid and semiarid rangelands; Experimental and modeling studies of effects of elevated CO2 and rainfall variability on dryland ecosystems

Research in my lab focuses on the direct effects of disturbance (e.g., drought, overgrazing, land-use change, elevated CO2 concentrations) on dryland ecosystems. My main interest is desertification (land degradation in drylands), a phenomenon often equated to a reduction in the biological and economic potential of land to support human populations, livestock and wild herbivores and which, ultimately, is linked to global environmental change through climate, biodiversity loss, human dimensions, and land use change. The long-term goals are to develop a quantitative understanding of dryland degradation in the context of the balance between natural and social systems, and through collaborations with socio-economic researchers, to address questions of direct relevance to human societies in these systems. In 2002 I established ARIDnet (the Assessment, Research, and Integration of Desertification research network; pdf available at: http://www.biology.duke.edu/aridnet/pdfs/NL_54_2_IGBPCitation.pdf), which is an NSF-supported initiative on global desertification that emphasizes the interdependencies of natural and human systems as mechanisms of dryland degradation. ARIDnet evolved out of a belief that there is a pressing need for new and creative interdisciplinary approaches for addressing the global problem of desertification that transcends regional and disciplinary concerns. Background information and further details can be found at http://www.biology.duke.edu/aridnet/). At the core of an integrated, coupled systems approach to the study of dryland ecosystems is the Patch Arid Lands Simulator (PALS), a physiologically-based model that simulates 1-dimensional fluxes of carbon (C), nitrogen (N), and water in a representative patch of vegetation. Students and postdocs in my lab have used PALS to explore potential whole ecosystem response to changes in (i) forcing functions (air temperature, size and timing of precipitation events, elevated CO2); (ii) system structure (e.g., shifts in plant functional type composition); and (iii) system function (changes in NEE, soil respiration, etc.). PALS was originally developed and validated for the northern Chihuahuan Desert, but has been modified for all of the warm deserts of North America, e.g., a comparative analysis of ecosystem responses to precipitation variability from 1915 to 2000 across a gradient of warm desert sites [Las Vegas, NV (Mojave), Tucson, AZ (Sonoran), and Jornada Experimental Range, NM (Chihuahuan) (Reynolds et al. 2004 Oecologia 141:194–210).

Current projects: NSF: Desertification research network (ARIDnet), USDA: Effects drought and grazing on historical rates of land degradation in southern New Mexico , NSF: Effects elevated CO2 on a Mojave Desert ecosystem , DOE: Ecosystem Warming Experiments: Modeling Microbial Indicators

Representative Publications   (More Publications)   (search)

1. REYNOLDS, JF, DM Stafford Smith, EF Lambin, BL Turner, II, M Mortimore, SPJ Batterbury, TE Downing, H Dowlatabadi, RJ Fernández, JE Herrick, E Huber-Sannwald, R Leemans, T Lynam, FT Maestre, M Ayarza & B Walker, Global desertification: Building a science for dryland development, Science, vol. 316 no. 5826 (May 11, 2007), pp. 847-851 .
2. REYNOLDS, J.F., Cutting through confusion. A new paradigm for understanding the interrelated factors that make up desertification, so as better to combat it, Our Planet, vol. 17 (July, 2006), pp. 26-27 [available here]  [author's comments].
3. Maestre, FT, JF REYNOLDS, E Huber-Sannwald, J Herrick, M Stafford-Smith, Understanding global desertification: biophysical and socioeconomic dimensions of hydrology, in Dryland Ecohydrology, edited by P. D'Odorico and A Porporato (February, 2006), pp. 315-332, Springer-Verlag, Dordrecht .
4. REYNOLDS, JF & DM Stafford Smith, Global Desertification: Do Humans Cause Deserts?, Dahlem Report 88 (December, 2002), pp. 437, Dahlem University Press (Berlin.) .
5. Maestre, FT & JF REYNOLDS, Small-scale spatial heterogeneity in the vertical distribution of soil nutrients has limited effects on the growth and development of Prosopis glandulosa seedlings, Plant Ecology, vol. 183 (March, 2006), pp. 65-75 .
6. REYNOLDS, JF, Desertification, in Encyclopedia Of Biodiversity, edited by S Levin (2001), pp. 61-78, Academic Press (San Diego, CA.) .
7. REYNOLDS, JF, PR Kemp, K Ogle, RJ Fernandez, Q Gao & J Wu, Modeling the unique attributes of desert ecosystems: Potentials and limitations based on lessons from the Jornada Basin, in Structure and Function of a Chihuahuan Desert Ecosystem, edited by KM Havstad, LF Huenneke & WH Schlesinger (August, 2006), pp. 321-353, Oxford University Press, Oxford, UK .
8. Ogle, K & JF REYNOLDS, Plant responses to precipitation in desert ecosystems: integrating functional types, pulses, thresholds, and delays, Oecologia, vol. 141 (2004), pp. 282–294 .
9. Gao, Q & JF REYNOLDS, Historical shrub-grass transitions in the northern Chihuahuan Desert: Modeling the effects of shifting rainfall seasonlity and event size over a landscape, Global Change Biology, vol. 9 (2003), pp. 1-19 .
10. REYNOLDS, James F, PR Kemp, K Ogle and RJ Fernández, Modifying the ‘pulse-reserve’ paradigm for deserts of North America: precipitation pulses, soil water and plant responses, Oecologia, vol. 141 (2004), pp. 194–210 .
11. Ogle, K, RL Wolpert & JF REYNOLDS, Reconstructing plant root area and water uptake profiles, Ecology, vol. 85 (2004), pp. 1967-1978 .
12. Maestre, FT, F Valladares & JF REYNOLDS, The stress-gradient hypothesis does not fit all relationships between plant-plant interactions and abiotic stress: further insights from arid environments, Journal of Ecology, vol. 94 (January, 2006), pp. 17-22 .
13. REYNOLDS, JF, RA Virginia, PR Kemp, AG De Soyza & DC Tremmel, Impact of simulated drought on resource islands of shrubs in the Chihuahuan Desert: Effects of species, season, and degree of island development, Ecological Monographs, vol. 63(1) (1999), pp. 69-106 .
14. Maestre, FT, F Valladares & JF REYNOLDS, Is the change of plant–plant interactions with abiotic stress predictable? A meta-analysis of field results in arid environments, Journal of Ecology, vol. 93 (2005), pp. 748–757 .
15. REYNOLDS, JF, PR Kemp & JD Tenhunen, Effects of long-term rainfall variability on evapotranspiration and soil wate distribution in the Chihuahuan Deser: a modeling analysis, Plant Ecology, vol. 150 (2000), pp. 145-159 .
16. Ogle, K & JF REYNOLDS, Desert dogma revisited: coupling of stomatal conductance and photosyntesis in the desert shrub, Larrea tridentata, Plant, Cell and Enviroment, vol. 25 (2002), pp. 909-921 .