University of Pittsburgh
Home › People ›

Walter Carson

Associate Professor

Plant Community Ecology

Walter Carson
walt@pitt.edu
Office: (412) 624-5496
Lab: (412) 624-5497
154A Crawford Hall
4249 Fifth Avenue
Pittsburgh, PA 15260
Web Site
Education

Dr. Carson received his Ph. D. in 1993 with Richard Root at Cornell University, performed his postdoctoral studies with David Tilman at the University of Minnesota and Steve Hubbell at Princeton University, and joined the Department in 1994.

The research in my lab continues to focus on four major areas. 

  1. We continue our experimental studies on the impact of herbivory on the diversity of tropical forests in Panama and Costa Rica.  We have established 26 large experimental plots in 3 forests in which over 50,000 trees have been tagged, mapped, measured and monitored for 10 years.  We have many collaborators on this work including faculty and graduate students at Tulane, Stanford, University of Connecticut, and the Smithsonian Tropical Research Institute. 
  2. We have extensive field experiments underway designed to evaluate the underlying causes of failed oak regeneration in West Virginia.  We have now established more than 64 large experimental plots designed evaluate the major causes of forest change in the eastern deciduous forest.  These processes include fire, canopy disturbance, and browsing.
  3. We are continuing our long-term experiments at PLE on the invasive wetland plant species, purple loosestrife.  In collaboration with scientists at the New Jersey Institute of Technology and the University of Georgia we are testing several of the key hypotheses associated with how exotic species can invade and dominate novel habitats.
  4. As part of a new research initiative, we have surveyed 20 old-growth forests remnants across Pennsylvania to evaluate whether these systems are threatened with biodiversity collapse.  Our findings show that these systems, once thought to represent examples of primeval forest, are on a successional pathway leading to near mono-dominance.
Recent Publications

  • Carson WP, CJ Peterson and AA Royo (In Press) A case study of chronic deer overbrowsing throughout the Allegheny National Forest region in Pennsylvania. Pages XXX-XXX in The herbaceous layer in forests of eastern North America, 2nd Edition (FS Gilliam and MR Roberts, editors), Oxford University Press: Oxford, UK

  • Reider KE, WP Carson, and MA Donnelly (In Press) Effects of collared peccary (Pecari tajacu) exclusion on leaf litter amphibians and reptiles in a Neotropical wet forest, Costa Rica. Biological Conservation doi:10.1016/j.biocon.2012.12.015

  • Schumacher H and WP Carson (In Press) Diversity loss and biotic homogenization in 19 late-successional and old-growth forest stands in Pennsylvania. Journal of the Torrey Botanical Society.

  • Yorke SR, SA Schnitzer, J Mascaro, SG Letcher and WP Carson (2013) Increasing liana abundance and basal area in a tropical forest: the contribution of long-distance clonal colonization. Biotropica 45:317-324

  • Nuttle T, AA Royo, MB Adams and WP Carson (2013) Historic disturbance regimes promote tree diversity only under low browsing regimes in eastern deciduous forest. Ecological Monographs 83:3-17

  • Pendergast TH, IV, DJ Burke and WP Carson (2013) Belowground biotic complexity drives aboveground dynamics: a test of the soil community feedback model. New Phytologist 197:1300-1310

  • Peterson CJ, LM Krueger, AA Royo, SC Stark and WP Carson (2013) Disturbance size and severity covary in small and mid-size wind disturbances in Pennsylvania northern hardwoods forests. Forest Ecology and Management 302:273-279

  • Dyer LA, WP Carson and EG Leigh Jr (2012) Insect outbreaks in tropical forests: patterns, mechanisms, and consequences. Pages 217-245 in Insect outbreaks revisited (P Barbosa, DK Letourneau and AA Agrawal, editors), Wiley-Blackwell: Oxford, UK

  • Hovick SM, CJ Peterson and WP Carson (2012) Predicting invasiveness and range size in wetland plants using biological traits: a multivariate experimental approach. Journal of Ecology 100:1373-1382

  • Goetsch C*, J Wigg*, AA Royo, T Ristau and WP Carson (2011) Chronic over browsing and biodiversity collapse in a forest understory in Pennsylvania: results from a 60 year-old deer exclusion plot. Journal of the Torrey Botanical Society 138:220-224

  • Hovick SM, DE Bunker, CJ Peterson and WP Carson (2011) Purple loosestrife suppresses plant species colonization far more than broad-leaved cattail: experimental evidence with plant community implications. Journal of Ecology 99:225-234

  • Kain M*, L Battaglia, A Royo, and WP Carson (2011) Over-browsing in Pennsylvania creates a depauperate forest dominated by an understory tree: results from a 60-year-old deer exclosure. Journal of the Torrey Botanical Society 138:322-326

  • Cronin JP, SJ Tonsor and WP Carson (2010) A simultaneous test of trophic interaction models: which vegetation characteristic explains herbivore control over plant community mass? Ecology Letters 13:202-212

  • Maron JL, DE Pearson, SM Hovick and WP Carson (2010) Funding needed for assessments of weed biological control. Frontiers in Ecology and the Environment 8:122-123

  • Royo AA and WP Carson (2010) The formation of dense understory layers in forests worldwide: consequences and implications for forest dynamics, biodiversity, and succession. Pages 469-496 in Advances in threat assessment and their application to forest and rangeland management. General Technical Report PNW-802 (JM Pye, HM Rauscher, Y Sands, DC Lee and JS Beatty, editors), United States Department of Agriculture, Forest Service, Pacific Northwest Research Station: Portland, Oregon, USA

  • Royo AA, R Collins, MB Adams, C Kirschbaum and WP Carson (2010) Pervasive interactions between ungulate browsers and disturbance regimes promote temperate forest herbaceous diversity. Ecology 91:93-105

  • Schnitzer SA and WP Carson (2010) Lianas suppress tree regeneration and diversity in treefall gaps. Ecology Letters 13:849-857

  • Krueger LM, CJ Peterson, A Royo and WP Carson (2009) Evaluating relationships among tree relative growth rate, shade-tolerance and browse-tolerance following disturbance in an eastern deciduous forest. Canadian Journal of Forest Research 39:2460-2469

  • Banta JA*, SC Stark*, MH Stevens, TH Pendergast IV, A Baumert and WP Carson (2008) Light reduction predicts widespread patterns of dominance between asters and goldenrod. Plant Ecology 199:65-76

  • Carson WP, JT Anderson, EG Leigh Jr and SA Schnitzer (2008) Challenges associated with testing and falsifying the Janzen-Connell Hypothesis: a review and critique. Pages 210-241 in Tropical forest community ecology (WP Carson and SA Schnitzer, editors), Wiley-Blackwell Publishing: Oxford, UK

  • Carson WP, SM Hovick, AJ Baumert, DE Bunker and TH Pendergast IV (2008) Evaluating the post-release efficacy of invasive plant biocontrol by insects: a comprehensive approach. Arthropod–Plant Interactions 2:76-86

  • Carson WP and SA Schnitzer (2008) Tropical forest community ecology. Wiley-Blackwell Publishing: Oxford, UK

  • Paine CE, KE Harms, SA Schnitzer and WP Carson (2008) Weak competition among tropical tree seedlings: implications for species coexistence. Biotropica 40:432-440

  • Peterson CJ and WP Carson (2008) Proceses constraining woody species succession on abandoned pastures in the tropics: on the relevance of temperate models of succession. Pages 367-383 in Tropical forest community ecology (WP Carson and SA Schnitzer, editors), Wiley-Blackwell Publishing: Oxford, UK

  • Royo AA and WP Carson (2008) Direct and indirect effects of a dense understory on tree seedling recruitment in temperate forests: habitat-mediated predation versus competition. Canadian Journal of Forest Research 38:1634-1645

  • Schnitzer SA, J Mascaro and WP Carson (2008) Treefall gaps and the maintenance of plant species diversity in tropical forests. Pages 196-209 in Tropical forest community ecology (WP Carson and SA Schnitzer, editors), Wiley-Blackwell Publishing: Oxford, UK

  • Long ZT, TH Pendergast IV and WP Carson (2007) The impact of deer on relationships between tree growth and mortality in an old-growth beech-maple forest. Forest Ecology and Management 252:230-238

  • Carson WP, T Elnaccash, C Heckel, TH Pendergast IV and M Urban* (2006) The world's rain forests: a primer on uniqueness. [Review of: Tropical rain forests: an ecological and biogeographical comparison, R Primack and R Corlett, 2005]. Ecology 87:1869-1870

  • Kurzal BP, SA Schnitzer and WP Carson (2006) Predicting liana crown location from stem diameter in three Panamanian lowland forests. Biotropica 32:262-266

  • Royo AA and WP Carson (2006) On the formation of dense understory layers in forests worldwide: consequences and implications for forest dynamics, biodiversity, and succession. Canadian Journal of Forest Research 36:1345-1362

  • Stark SC*, DE Bunker and WP Carson (2006) A null model of exotic plant diversity tested with exotic and native species-area relationships. Ecology Letters 9:136-141

  • Banta JA*, AA Royo, C Kirschbaum and WP Carson (2005) Plant communities growing on boulders in the Allegheny national forest: evidence for boulders as refugia from deer and as a bioassay of overbrowsing. Natural Areas Journal 25:10-18

  • Bunker DE, and WP Carson (2005) Drought stress and tropical forest woody seedlings: effect on community structure and composition. Journal of Ecology 93:794-806

  • Comisky L*, AA Royo and WP Carson (2005) Deer browsing creates rock refugia gardens on large boulders in the Allegheny National Forest, Pennsylvania. American Midland Naturalist 154:201-206

  • Royo AA and WP Carson (2005) The herb community of a tropical forest in central Panama: dynamics and impact of mammalian herbivores. Oecologia 145:66-75

  • Carson WP, JP Cronin and ZT Long (2004) A general rule for predicting when insects will have strong top-down effects on plant communities: on the relationship between insect outbreaks and host concentration. Pages 193-211 in Insects and ecosystem function. Ecological studies 173 (WW Weisser and E Siemann, editors), Springer-Verlag: Berlin, Germany

  • Collins RJ and WP Carson (2004) The effects of environment and life stage on Quercus abundance in the eastern deciduous forest, USA: are sapling densities most responsive to environmental gradients? Forest Ecology and Management 201:241-258

  • Mascaro J, SA Schnitzer and WP Carson (2004) Liana diversity, abundance, and mortality in a tropical wet forest in Costa Rica. Forest Ecology and Management 190:3-14

  • Siemann E, WP Carson, WE Rogers and WW Weisser (2004) Reducing herbivory using insecticides. Pages 303-327 in Insects and ecosystem function. Ecological studies 173 (WW Weisser and E Siemann, editors), Springer-Verlag: Berlin, Germany

  • Stevens MHH, DE Bunker, SA Schnitzer and WP Carson (2004) Establishment limitation reduces species recruitment and species richness as soil resources rise. Journal of Ecology 92:339-347

  • Carson WP and SA Schnitzer (2003) Deep rainforest ecology. [Review of: Nouragues: dynamics and plant-animal interactions in a Neotropical rainforest. F Bongers, P Charles-Dominique, P-M Forget and M Théry, editors, 2002]. Ecology 84:1340-1341

  • Collins RJ and WP Carson (2003) The fire and oak hypothesis: incorporating the effects of deer browsing and canopy gaps. Pages 44-63 in Proceedings of the 13th Central Hardwood Forest Conference. General Technical Report NC-234 (JW Van Sambeek, JO Dawson, F Ponder, EF Loewenstein and JS Fralish, editors), United States Department of Agriculture, Forest Service, Northern Research Station: St. Paul, Minnesota, USA

  • Long ZT, CL Mohler and WP Carson (2003) Extending the resource concentration hypothesis to plant communities: effects of litter and herbivores. Ecology 84:652-665

  • McGill DW, RJ Collins and WP Carson (2003) Response of pin cherry to fire, canopy disturbance and deer herbivory on the Westvaco Wildlife and Ecosystem Research Forest. Pages 282-293 in Proceedings of the 13th Central Hardwood Forest Conference. General Technical Report NC-234 (JW Van Sambeek, JO Dawson, F Ponder, EF Loewenstein and JS Fralish, editors), United States Department of Agriculture, Forest Service, Northern Research Station: St. Paul, Minnesota, USA

  • Cronin JP and WP Carson (2002) Competition. Encyclopedia of life sciences, Macmillan: New York, New York, USA

  • Schnitzer SA, PB Reich, B Bergner and WP Carson (2002) Herbivore and pathogen damage on grassland and woodland plants: a test of the herbivore uncertainty principle. Ecology Letters 5:531-539

  • Stevens MHH and WP Carson (2002) Resource quantity, not resource heterogeneity, maintains plant diversity. Ecology Letters 5:420-426

  • Schnitzer SA and WP Carson (2001) Treefall gaps and the maintenance of species diversity in a tropical forest. Ecology 82:913-919

  • Stevens MHH and WP Carson (2001) Phenological complementarity, species diversity, and ecosystem function. Oikos 92:291-296

  • Carson WP and RB Root (2000) Herbivory and plant species coexistence: community regulation by an outbreaking phytophagous insect. Ecological Monographs 70:73-99

  • Schnitzer SA and WP Carson (2000) Have we forgotten the forest because of the trees? Trends in Ecology & Evolution 15:375-376

  • Schnitzer SA, JW Dalling and WP Carson (2000) The impact of lianas on tree regeneration in tropical forest canopy gaps: evidence for an alternative pathway of gap-phase regeneration. Journal of Ecology 88:655-666

  • Carson WP (1999) A primer on how to apply and get admitted to graduate school in ecology and evolutionary biology. Bulletin of the Ecological Society of America 80:246-250

  • Carson WP and RB Root (1999) Top-down effects of insect herbivores during early succession: influence on biomass and plant dominance. Oecologia 121:260-272

  • Lawson D, RS Inouye, N Huntly and WP Carson (1999) Patterns of woody plant abundance, recruitment, mortality, and growth in a 65 year chronosequence of old-fields. Plant Ecology 145:267-279

  • Schnitzer SA and WP Carson (1999) Tropical environments. Pages 605-609 in Encyclopedia of environmental science (DE Alexander and RW Fairbridge, editors), Chapman and Hall: London, UK

  • Stevens MHH and WP Carson (1999) Plant density determines species richness along an experimental fertility gradient. Ecology 80:455-465

  • Stevens MHH and WP Carson (1999) The significance of assemblage-level thinning for species richness. Journal of Ecology 87:490-502

  • Long ZT, WP Carson and CJ Peterson (1998) Can disturbance create refugia from herbivores: an example with hemlock regeneration on treefall mounds. Journal of the Torrey Botanical Society 125:165-168

  • Peterson CJ and WP Carson (1996) Generalizing forest regeneration models: the dependence of propagule availability on disturbance history and stand size. Canadian Journal of Forest Research 26:45-52

  • Stevens MHH, DF Raikow, MR Servedio, RJ Collins, TL Schumann, AN Tipper and WP Carson (1996) Hutchinson's chariot. [Review of: Specied diversity in space and time, TL Rosenzweig, 1995]. Bulletin of the Botanical Society of America 42:48-49

  • Belsky AJ, WP Carson, CL Jensen and GA Fox (1993) Overcompensation by plants: herbivore optimization or red herring? Evolutionary Ecology 7:109-121

  • Cain ML, WP Carson and RB Root (1991) Long-term suppression of insect herbivores increases the production and growth of Solidago altissima rhizomes. Oecologia 88:251-257

  • Facelli JM and WP Carson (1991) Heterogeneity of plant litter accumulation in successional commmunities. Bulletin of the Torrey Botanical Club 118:62-66

  • Vankat JL and WP Carson (1991) Floristics of a chronosequence corresponding to old field deciduous forest succession in southwestern Ohio. 3. Post-disturbance vegetation. Bulletin of the Torrey Botanical Club 118:385-391

  • Carson WP and DK Abbiw (1990) The vegetation of a fire protection site on the northern Accra Plains, Ghana. African Journal of Ecology 28:143-146

  • Carson WP and CJ Peterson (1990) The role of litter in an old-field community: impact of litter quantity in different seasons on plant-species richness and abundance. Oecologia 85:8-13

  • Carson WP and STA Pickett (1990) Role of resources and disturbance in the organization of an old-field plant community. Ecology 71:226-238

  • Peterson CJ, WP Carson, BC McCarthy and STA Pickett (1990) Microsite variation and soil dynamics within newly created treefall pits and mounds. Oikos 58:39-46

  • Carson WP and GW Barrett (1988) Succession in old-field plant communities: effects of contrasting types of nutrient enrichment. Ecology 69:984-994

  • Pickett STA and WP Carson (1987) Review of: Ecology: individuals, populations, communities, M Begon, JL Harper and CR Townsend, 1986. Brittonia 39:407-408

  • Carson WP (1985) The ecology of the Accra and Winneba Plains with some aspects of related savanna ecosystems. Pages 4-74 in Impact of human activities on the structure and productivity of the savanna ecosystem in Ghana. Ghana National Committee for the Man and the Biosphere Program. Volume I. (BW Garbrah, editor), UNESCO/MAB: Accra, Ghana

E-mail Lab