Jake F. Weltzin
Jake joined the US Geological Survey in 2007 to design and implement the USA National Phenology Network. Since 2015 he has also served as the Program Manager for the Status & Trends Program in the Ecosystems Mission Area.
Jake’s interest in natural history developed as he grew up in Alaska and served as an exchange student in the Australian outback. His interests range broadly -- from natural resource management to ecological- and ecosystem-level research -- across a variety of systems ranging from deserts to grasslands, savannas to forests, and even to wetlands.
Research Interests
Jake is interested in how the structure and function of plant and animal populations, communities and ecosystems respond to global environmental change, including atmospheric chemistry, climate change, and biological invasions. He also studies how scientists understand and describe changes in ecosystems over space and time, from monitoring, to data management and analysis, to delivery of ecological knowledge and information to stakeholders. Current interests include citizen science, enterprise tools for monitoring, data visualization and delivery, and ecological forecasting.
Professional Experience
Post-doctoral Fellowship at University of Notre Dame
Associate Professor, University of Tennessee
Program Director, National Science Foundation
Executive Director, USA National Phenology Network
Program Manager, Status & Trends Program, US Geological Survey
Education and Certifications
B.S., Colorado State University
M.S., Texas A&M University
Ph.D., University of Arizona
Science and Products
Differential changes in the onset of spring across US National Wildlife Refuges and North American migratory bird flyways
USA National Phenology Network supports decision making
National Park Service and the USA National Phenology Network
Phenology forecasts predict pest seasonal activity to support decision making
MonitoringResources.org—Supporting coordinated and cost-effective natural resource monitoring across organizations
USA National Phenology Network observational data documentation
A science products inventory for citizen-science planning and evaluation
Development and release of phenological data products—A case study in compliance with federal open data policy
Ecosystems, Ecosystem Services, and Biodiversity
Developing enterprise tools and capacities for large-scale natural resource monitoring: A visioning workshop
US Fish and Wildlife Service and the USA National Phenology Network
USA National Phenology Network’s volunteer-contributed observations yield predictive models of phenological transitions
Non-USGS Publications**
Arizona Press, Tucson
**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
Science and Products
- Science
- Multimedia
- Publications
Filter Total Items: 61
Differential changes in the onset of spring across US National Wildlife Refuges and North American migratory bird flyways
Warming temperatures associated with climate change can have indirect effects on migratory birds that rely on seasonally available food resources and habitats that vary across spatial and temporal scales. We used two heat-based indices of spring onset, the First Leaf Index (FLI) and the First Bloom Index (FBI), as proxies of habitat change for the period 1901 to 2012 at three spatial scales: the UAuthorsEric K. Waller, Theresa M. Crimmins, Jessica J. Walker, Erin E. Posthumus, Jake WeltzinUSA National Phenology Network supports decision making
The USA National Phenology Network is a federally-funded, nationalscale science and monitoring initiative focused on phenology as a tool to understand how plants, animals, and landscapes respond to environmental variation and change.AuthorsJake Weltzin, Theresa M. Crimmins, Erin E. Posthumus, Alyssa RosemartinNational Park Service and the USA National Phenology Network
Understanding the seasonal cycles of plants and animals, how they are changing, and how they can inform management, operations, and interpretation is critical to the mission of the National Park Service (NPS): to preserve unimpaired the natural and cultural resources and values of the National Park System for the enjoyment, education, and inspiration of this and future generations.AuthorsJake Weltzin, Theresa M. Crimmins, Erin E. Posthumus, Alyssa RosemartinPhenology forecasts predict pest seasonal activity to support decision making
The USA National Phenology Network (USANPN) produces and distributes daily national phenology maps – or Pheno Forecasts – indicating when key pest species may be most susceptible to management as part of a growing suite of phenology map products. The USA-NPN’s Pheno Forecast maps show when key pest species, including emerald ash borer (Agrilus planipennis), apple maggot (Rhagoletis pomonella), lilAuthorsJake Weltzin, Theresa M. Crimmins, Erin Posthumous, Alyssaa Rosemartin, Katharine L. GerstMonitoringResources.org—Supporting coordinated and cost-effective natural resource monitoring across organizations
Natural resource managers who oversee the Nation’s resources require data to support informed decision-making at a variety of spatial and temporal scales that often cross typical jurisdictional boundaries such as states, agency regions, and watersheds. These data come from multiple agencies, programs, and sources, often with their own methods and standards for data collection and organization. CooAuthorsJennifer M. Bayer, Rebecca A. Scully, Jake WeltzinUSA National Phenology Network observational data documentation
The goals of the USA National Phenology Network (USA-NPN, www.usanpn.org) are to advance science, inform decisions, and communicate and connect with the public regarding phenology and species’ responses to environmental variation and climate change. The USA-NPN seeks to advance the science of phenology and facilitate ecosystem stewardship by providing phenological information freely and openly. ToAuthorsAlyssa H. Rosemartin, Ellen G. Denny, Katharine L. Gerst, R. Lee Marsh, Erin E. Posthumus, Theresa M. Crimmins, Jake WeltzinA science products inventory for citizen-science planning and evaluation
Citizen science involves a range of practices involving public participation in scientific knowledge production, but outcomes evaluation is complicated by the diversity of the goals and forms of citizen science. Publications and citations are not adequate metrics to describe citizen-science productivity. We address this gap by contributing a science products inventory (SPI) tool, iteratively develAuthorsAndrea Wiggins, Rick Bonney, Gretchen LeBuhn, Julia K. Parrish, Jake WeltzinDevelopment and release of phenological data products—A case study in compliance with federal open data policy
In Autumn 2015, USA National Phenology Network (USA-NPN) staff implemented new U.S. Geological Survey (USGS) data-management policies intended to ensure that the results of Federally funded research are made available to the public. The effort aimed both to improve USA-NPN data releases and to provide a model for similar programs within the USGS. This report provides an overview of the steps takenAuthorsAlyssa H. Rosemartin, Madison L. Langseth, Theresa Crimmins, Jake F. WeltzinEcosystems, Ecosystem Services, and Biodiversity
Biodiversity—the variety of life on Earth—provides vital services that support and improve human health and well-being. Ecosystems, which are composed of living things that interact with the physical environment, provide numerous essential benefits to people. These benefits, termed ecosystem services, encompass four primary functions: provisioning materials, such as food and fiber; regulating critAuthorsDouglas Lipton, Madeleine A. Rubenstein, Sarah R. Weiskopf, Shawn L. Carter, Jay Peterson, Lisa Crozier, Michael Fogarty, Sarah Gaichas, Kimberly J. W. Hyde, Toni Lyn Morelli, Jeffrey Morisette, Hassan Moustahfid, Roldan Munoz, Rajendra Poudel, Michelle D. Staudinger, Charles Stock, Laura Thompson, Robin S. Waples, Jake WeltzinDeveloping enterprise tools and capacities for large-scale natural resource monitoring: A visioning workshop
In October 2016, the U.S. Geological Survey (USGS), in collaboration with the Pacific Northwest Aquatic Monitoring Partnership (PNAMP, www.pnamp.org), convened a 30-person workshop, https://www.pnamp.org/event/5509, to identify and prioritize development of enterprise systems for programs that monitor the status and trends of species populations and their terrestrial, aquatic, and marine habitats.AuthorsJennifer M. Bayer, Jake Weltzin, Rebecca A. ScullyUS Fish and Wildlife Service and the USA National Phenology Network
Understanding the seasonal cycles of plants and animals, how they are changing, and how these changes can inform management, operations, and interpretation is critical to the mission of the US Fish and Wildlife Service (FWS): to work with others to conserve, protect, and enhance fish, wildlife, plants, and their habitats for the continuing benefit of the American people. Phenology monitoring is paAuthorsJake F. Weltzin, Theresa Crimmins, Erin E. Posthumus, Alyssa H. RosemartinUSA National Phenology Network’s volunteer-contributed observations yield predictive models of phenological transitions
In support of science and society, the USA National Phenology Network (USA-NPN) maintains a rapidly growing, continental-scale, species-rich dataset of plant and animal phenology observations that with over 10 million records is the largest such database in the United States. Contributed voluntarily by professional and citizen scientists, these opportunistically collected observations are characteAuthorsTheresa M. Crimmins, Michael A. Crimmins, Katherine L. Gerst, Alyssa H. Rosemartin, Jake WeltzinNon-USGS Publications**
Resco de Dios, V., J.F. Weltzin, W. Sun, T.E. Huxman and D.G. Williams. 2014. Transitions from grassland to savanna under drought via passive facilitation by grasses. Journal of Vegetation Science 25:937–946. DOI: 10.1111/jvs.12164Resco de Dios, V., J.F. Weltzin, W. Sun, T.E. Huxman, and D.G. Williams. 2012. Windows of opportunity for Prosopis velutina seedling establishment and encroachment in a semiarid grassland. Perspectives in Plant Ecology, Evolution and Systematics 14:275-282. DOI: 10.1016/j.ppees.2012.03.002Souza, L. J.F. Weltzin, and N.J. Sanders. 2011. Differential effects of two dominant plant species on community structure and invasibility in an old-field ecosystem. Journal of Plant Ecology 4:123-131. DOI: 10.1093/jpe/rtq027
Souza, L., W.A. Bunn, J.F. Weltzin, and N.J. Sanders. 2011. Similar biotic factors affect early establishment and abundance of an invasive plant species across spatial scales. Biological Invasions 13:255-267. DOI: 10.1007/s10530-010-9805-9Kardol, P., C.E. Campany, L. Souza, R.J. Norby, J.F. Weltzin and A.T. Classen. 2010. Climate change effects on plant biomass alter dominance patterns and community evenness in an experimental old-field ecosystem. Global Change Biology 16:2676–2687. DOI: 10.1111/j.1365-2486.2010.02162.xSouza, L., R.T. Belote, P. Kardol, J.F. Weltzin and R.J. Norby. 2010. CO2 enrichment accelerates successional development of an understory plant community. Journal of Plant Ecology 3:33-39. DOI: 10.1093/jpe/rtp032Classen, A.T., R.J. Norby, C.E. Campany, K.E. Sides, and J.F. Weltzin. 2010. Climate change alters seedling emergence and establishment in an old-field ecosystem. PLoS ONE 5(10): e13476. doi:10.1371/journal.pone.0013476
Engel, E.C., J.F. Weltzin, R.J. Norby, and A.T. Classen. 2009. Responses of an old-field plant community to interacting factors of elevated [CO2], warming, and soil moisture. Journal of Plant Ecology 2:1-11. DOI: 10.1093/jpe/rtn026Resco de Dios, V., B.E. Ewers, W. Sun, T.E. Huxman, J.F. Weltzin and D.G. Williams. 2009. Drought-induced hydraulic limitations constrain leaf gas exchange recovery after precipitation pulses in the C3 woody legume, Prosopis velutina. New Phytologist 181: 672–682Bridgham, S.D., J. Pastor, B. Dewey, J.F. Weltzin, and K. Updegraff. 2008. Rapid carbon response of peatlands to climate change. Ecology 89:3041-3048. DOI: 10.1890/08-0279.1Cable, J.M., K. Ogle, D.G. Williams, J.F. Weltzin and T.E. Huxman. 2008. Soil texture drives responses of soil respiration to precipitation pulses in the Sonoran desert: implications for climate change. Ecosystems 11:961-979. DOI: 10.1007/s10021-008-9172-xWhite, J. R., R. D. Shannon, S.D. Bridgham, J. F. Weltzin, and J. Pastor. 2008. Effects of soil warming and drying on methane cycling in a northern peatland mesocosm study. Journal of Geophysical Research 113: G00A06. DOI: 10.1029/2007JG000609McPherson, G.R. and J.F. Weltzin. 2008. Implications of peak oil for industrialized societies. Bulletin of Science, Technology & Society 28:187-191. DOI: 10.1177/0270467608316098Chen, J.Q., S.D. Bridgham, J. Pastor, A. Noormets, J. Keller, and J.F. Weltzin. 2008. Temperature responses to infrared-loading and water table manipulations in peatland mesocosms. Journal of Integrative Plant Biology 50:1484-1496. DOI: 10.1111/j.1744-7909.2008.00757.xResco de Dios, V., D.D. Ignace, W. Sun, T.E. Huxman, J.F. Weltzin and D.G. Williams. 2008. Chlorophyll fluorescence, predawn water potential and photosynthesis in precipitation pulse-driven ecosystems – implications for ecological studies. Functional Ecology 22:479-483. DOI: 10.1111/j.1365-2435.2008.01396.xDermody, O, J.F. Weltzin, E.C. Engel, P. Allen, and R.J. Norby. 2008. How do elevated [CO2], warming, and reduced precipitation interact to affect soil moisture and LAI in an old field ecosystem? Plant and Soil 295:217- 227. DOI: 10.1007/s11104-007-9443-xEngel, E.C. and J.F. Weltzin. 2008. Can community composition be predicted from pairwise species interactions? Plant Ecology 195:77-85. DOI: 10.1007/s11258-007-9300-2Wan, S., R.J. Norby, J. Ledford, and J.F. Weltzin. 2007. Responses of soil respiration to elevated CO2, air warming, and soil water availability in a model old-field grassland. Global Change Biology 13:2411–2424. DOI: 10.1111/j.1365-2486.2007.01433.xPerkins, T.A., W.R. Holmes, and J.F. Weltzin. 2007. Multi-species interactions in competitive hierarchies: New methods and empirical test. Journal of Vegetation Science 18:685-692. Runner-up, 2007 Editors’ Award; J. Veg. Sci. (2008) 19:1-2. DOI: 10.3170/2008-8-18468Sanders, N.J., J.F. Weltzin, G.M. Crutsinger, M.C. Fitzpatrick, M.A. Nuñez, C.M. Oswalt, and K.E. Lane. 2007. Insects mediate the effects of propagule supply and resource availability on a plant invasion. Ecology 88:2383-2391. DOI: 10.1890/06-1449.1Fortner, A.M. and J.F. Weltzin. 2007. Competitive hierarchy for four common old-field plant species depends on resource identity and availability. Journal of the Torrey Botanical Society 134:166-176. DOI: 10.3159/1095-5674(2007)134[166:CHFFCO]2.0.CO;2Ignace, D.D., T.E. Huxman, J.F. Weltzin and D.G. Williams. 2007. Leaf gas exchange and water status responses of a native and non-native grass to precipitation across contrasting soil surfaces in the Sonoran Desert. Oecologia. DOI: 10.1007/s00442-007-0670-xFitzpatrick, M.C., J.F. Weltzin, N.J. Sanders, and R.R. Dunn. 2007. The biogeography of prediction error: Why does the introduced range of the fire ant over predict its native range? Global Ecology and Biogeography 16:24-33. DOI: 10.1111/j.1466-822x.2006.00258.xBelote, R.T. and J.F. Weltzin. 2006. Interactions between two co-dominant, invasive plants in the understory of a temperate deciduous forest. Biological Invasions 8:1629-1641. DOI: 10.1007/s10530-005-3932-8Potts, D.L., T.E. Huxman, J.M. Cable, N.B. English, D.D. Ignace, J.A. Eilts, M.J. Mason, J.F. Weltzin and D.G. Williams. 2006. Antecedent moisture and seasonal precipitation influence response of canopy scale carbon and water exchange to rainfall pulses in semi arid grassland. New Phytologist. DOI: 10.1111/j.1469-8137.2006.01732.xWeltzin, J.F., R. T. Belote, L.T. Williams, J.K. Keller, and E.C. Engel. 2006. Authorship in ecology: attribution, accountability, and responsibility. Frontiers in Ecology and the Environment 4:435-441. DOI: 10.1890/1540-9295(2006)4[435:AIEAAA]2.0.CO;2 [Reply to comments: Weltzin, J.F., R. T. Belote, L.T. Williams, J.K. Keller, and E.C. Engel. 2007. Ensuring that “authors” write - the authors reply. Frontiers in Ecology and the Environment 5:11].Heisler, J.L. and J.F. Weltzin. 2006. Variability matters: towards a perspective on the influence of precipitation on terrestrial ecosystems. New Phytologist 172:189-192. DOI: 10.1111/j.1469-8137.2006.01876.xPotts, D.L., T.E. Huxman, B.J. Enquist, J.F. Weltzin, and D.G. Williams. 2006. Resilience and resistance of ecosystem functional response to a precipitation pulse in a semi arid grassland. Journal of Ecology 94:23-30. DOI: 10.1111/j.1365 2745.2005.01060.x.English, N.B., J.F. Weltzin, A. Fravolini, L.M. Thomas and D.G. Williams. 2005. The influence of soil texture and vegetation on soil moisture under rainout shelters in a semi-desert grassland. Journal of Arid Environments 63:324-343. DOI: 10.1016/j.jaridenv.2005.03.013Yepez, E.A., T.E. Huxman, D.D. Ignace, N.B. English, J.F. Weltzin, A.E. Castellanos, and D.G. Williams. 2005. Dynamics of transpiration and evaporation following a moisture pulse in semiarid grassland: a chamber based isotope method for partitioning flux components. Agricultural and Forest Meteorology 132:359-376. DOI: 10.1016/j.agrformet.2005.09.006Cole, P.G. and J.F. Weltzin. 2005. Light limitation creates patchy distribution of a non-native grass in eastern deciduous forests. Biological Invasions 7:477-488.Weltzin1, J.F., J.K. Keller1, S.D. Bridgham, J. Pastor, P.B. Allen, and J. Chen. 2005. Litter as a control on fen plant community composition and production. Oikos 110:537-546. 1Authors contributed equally.Fitzpatrick, M.C. and J.F. Weltzin. 2005. Ecological niche models and the geography of biological invasions: a review and a novel application. Pages 45-60 in Inderjit, editor. Ecological and Agricultural Aspects of Invasive Plants. Birkhauser Verlag/Switzerland.Sanders, N.J., R.T. Belote and J.F. Weltzin. 2004. Multi trophic effects of elevated CO2 on understory plant and arthropod communities. Environmental Entomology 33:1609-1616.Noormets, A., J. Chen, S.D. Bridgham, J. Pastor, J.F. Weltzin, B. Dewey, and J. LeMoine. 2004. The effects of infrared loading and water table on soil energy fluxes in northern peatlands. Ecosystems 7:573-582.Chesson, P., R.L.E. Gebauer, S. Schwinning, N. Huntly, K. Wiegand, M.S.K. Ernest, A. Sher, A. Novoplansky, and J.F. Weltzin. 2004. Resource pulses, species interactions, and diversity maintenance in arid and semi arid environments. Oecologia 141:236-253.Cole, P.G. and J.F. Weltzin. 2004. Environmental correlates of the distribution and abundance of Microstegium vimineum in East Tennessee, USA. Southeastern Naturalist 3:545-562.Huxman1, T.E., M.D. Smith1, P.A. Fay, A.K. Knapp, M.R. Shaw, M.E. Loik, S.D. Smith, D.T. Tissue, J.C. Zak, J.F. Weltzin, W.T. Pockman, O.E. Sala, B. Haddad, J. Harte, G.W. Koch, S. Schwinning, E.E. Small, and D.G. Williams. 1Authors contributed equally. 2004. Convergence across biomes to a common rain-use efficiency. Nature 429:651-654.Belote, R.T., J.F. Weltzin, and R.J. Norby. 2004. Response of an understory plant community to elevated [CO2] depends on differential responses of dominant invasive species and is mediated by soil water availability. New Phytologist 161:827-835.Huxman, T.E., J.M. Cable, D. D. Ignace, J.A. Eilts, N.B. English, J.F. Weltzin, and D.G. Williams. 2004. Response of net ecosystem gas exchange to a simulated precipitation pulse in a semi-arid grassland: the role of native versus non-native grasses and soil texture. Oecologia 141:295 305.English, N.B., D.G. Williams, and J.F. Weltzin. 2003. Soil temperature and moisture dynamics after experimental irrigation on two contrasting soils on the Santa Rita Experimental Range: implications for mesquite establishment. Pages 188-192 in McClaran, M.P., P.F. Ffolliott, and C.B. Edminster, tech coords. Santa Rita Experimental Range: 100 Years (1903 2003) of Accomplishments and Contributions. USDA Forest Service Proceedings RMRS-P-30.Weltzin, J.F., M.E. Loik, S. Schwinning, D.G. Williams, P. Fay, B. Haddad, J. Harte, T.E. Huxman, A.K. Knapp, G. Lin, W.T. Pockman, M.R. Shaw, E. Small, M.D. Smith, S.D. Smith, D.T. Tissue, and J.C. Zak. 2003. Assessing the response of terrestrial ecosystems to potential changes in precipitation. BioScience 53:941-952.Weltzin, J.F., N.Z. Muth, B. VonHolle, and P.G. Cole. 2003. Genetic diversity and invasibility: a test using a model system with a novel experimental design. Oikos 103:505-518.Price, C.A. and J.F. Weltzin. 2003. Managing non-native plant populations through intensive plant community restoration in Cades Cove, Great Smoky Mountains National Park, USA. Restoration Ecology 11:351-358.Drake, S.J., J.F. Weltzin, and P.D. Parr. 2003. Assessment of non-native invasive plants on the National Environmental Research Park at Oak Ridge National Laboratory. Castanea 68:15-30.Weltzin, J.F. and P.B. Allen. 2003. Tree seedling recruitment in temperate deciduous forest: interactive effects of soil moisture, light, and slope position. Pages 217 - 226 in Hanson, P.J. and S.D. Wullschleger, eds. North American temperate deciduous forest responses to changing precipitation regimes. Ecological Studies, Volume 166. Springer Verlag, New York.Weltzin, J.F., R.T. Belote, and N.J. Sanders. 2003. Biological invaders in a greenhouse world: will elevated CO2 fuel plant invasions? Frontiers in Ecology and the Environment 1:146-153.Weltzin, J.F., S.D. Bridgham, J. Pastor, J. Chen, and C. Harth. 2003. Potential effects of warming and drying on peatland plant community composition. Global Change Biology 9:141-151.Weltzin, J.F. and D.T. Tissue. 2003. Resource pulses in arid environments - patterns of rain, patterns of life. New Phytologist 157:171-173.Weltzin, J.F. and G.R. McPherson. 2003. Assessing response of terrestrial populations, communities, and ecosystems to changes in precipitation regimes: progress to date and future directions. Pages 180-188 in Weltzin, J.F. and G.R. McPherson, eds. Changing Precipitation Regimes and Terrestrial Ecosystems: A North American Perspective. University of Arizona Press, Tucson.Weltzin, J.F. and G.R. McPherson. 2003. Predicting the response of terrestrial ecosystems to potential changes in precipitation regimes. Pages 3-8 in Weltzin, J.F. and G.R. McPherson, eds. Changing Precipitation Regimes and Terrestrial Ecosystems: A North American Perspective. University of Arizona Press, TucsonWeltzin, J.F. and G.R. McPherson. 2003. Response of southwestern oak savannas to potential future precipitation regimes. Pages 127-146 in Weltzin, J.F. and G.R. McPherson, eds. Changing Precipitation Regimes and Terrestrial Ecosystems: A North American Perspective. University of
Arizona Press, Tucson
Pastor, J., B. Peckman, S.D. Bridgham, J.F. Weltzin, and J. Chen. 2002. Plant community dynamics, nutrient cycling, and alternative stable equilibria in peatlands. American Naturalist 160:553-568.R.J. Norby, P.J. Hanson, E.G. O'Neill, T.J. Tschaplinski, J.F. Weltzin, R.T. Hansen, W. Cheng, S.D. Wullschleger, C.A. Gunderson, N.T. Edwards, and D.W. Johnson. 2002. Net primary productivity of a CO2-enriched deciduous forest and the implications for carbon storage. Ecological Applications 12:1261-1266.Weltzin, J.F., K.A. Snyder, and D.G. Williams. 2001. Experimental manipulations of precipitation seasonality: effects on oak (Quercus) seedling demography and physiology. Western North American Naturalist 61:463-472.Weltzin, J.F., C. Harth, S.D. Bridgham, J. Pastor, and M. Vonderharr. 2001. Production and microtopography of bog bryophytes: response to warming and water-table manipulations. Oecologia 128:557-565.McPherson, G.R. and J.F. Weltzin. 2000. Disturbance and climate change in United States/Mexico borderland plant communities: A state-of-the-knowledge review. USDA Forest Service Rocky Mountain Research Station General Technical Report RMRS-GTR-50. 20 ppHanson, P.J. and J.F. Weltzin. 2000. Drought and climate change as vectors of disturbance in temperate forest communities. Science of the Total Environment 262:205-220Weltzin, J.F. and G.R. McPherson. 1999. Facilitation of conspecific seedling recruitment and shifts in temperate savanna ecotones. Ecological Monographs 69:513-534Weltzin, J.F., J. Pastor, C. Harth, S.D. Bridgham, K. Updegraff, and C.T. Chapin. 2000. Response of bog and fen plant communities to warming and water-table manipulations. Ecology 81:3464-3478.Weltzin, J.F. and G.R. McPherson. 2000. Implications of precipitation redistribution for shifts in temperate savanna ecotones. Ecology 81:1902-1913Williams, D.G., G.R. McPherson, and J.F. Weltzin. 1999. Stress in wildland plants: implications for ecosystem structure and function. Pages 907 929 in M. Pessarakli, ed. Handbook of plant and crop stress, second edition. Marcel Dekker, New York, NY.Weltzin, J.F., S.R. Archer, and R.K. Heitschmidt. 1998. Defoliation and woody plant (Prosopis glandulosa) seedling establishment: potential vs. realized herbivory tolerance. Plant Ecology 138:127-135McPherson, G.R. and J.F. Weltzin. 1998. Herbaceous response to canopy removal in southwestern oak woodlands. Journal of Range Management 51:674-678Weltzin, J.F., S.R. Archer, and R.K. Heitschmidt. 1997. Small mammal regulation of vegetation structure in a temperate savanna. Ecology 78:751-763Weltzin, J.F., S.L. Dowhower, and R.K. Heitschmidt. 1997. Prairie dog effects on plant community structure in southern mixed-grass prairie. Southwestern Naturalist 42:251-258.Weltzin, J.F. and G.R. McPherson. 1997. Spatial and temporal soil moisture resource partitioning by trees and savannas in a temperate savanna, Arizona, USA. Oecologia 112:156-164.Germaine, H.L., G.R. McPherson, K. Rojahn, A. Nicholas, and J.F. Weltzin. 1997. Constraints on germination and emergence of Emory oak. Pages 225-230 in R.B. Standiford, technical coordinator. Proceedings of a Symposium on Oak Woodlands: Ecology, Management, and Urban Interface Issues. USDA Forest Service Pacific Southwest Experiment Station General Technical Report PSW-160, Berkeley, CaliforniaWeltzin, J.F. and G.R. McPherson. 1995. Potential effects of climate change on lower treelines in the southwestern United States. Pages 180-193 in DeBano, L.F., G.J. Gottfried, R.H. Hamre, C.B. Edminster, P.F. Ffolliott, and A. Ortega-Rubio, technical coordinators. Biodiversity and Management of the Madrean Archipelago: The Sky Islands of Southwestern United States and Northwestern Mexico. USDA Forest Service Rocky Mountain Experiment Station General Technical Report RM-264, Fort Collins, ColoradoWeltzin, J. F. and M.B. Coughenour. 1990. Savanna tree influence on understory vegetation and soil nutrients in northwestern Kenya. Journal of Vegetation Science 1:325-334.**Disclaimer: The views expressed in Non-USGS publications are those of the author and do not represent the views of the USGS, Department of the Interior, or the U.S. Government.
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