Plant Ecology

, Volume 215, Issue 8, pp 927–935 | Cite as

Population dynamics in canopy gaps: nonlinear response to variable light regimes by an understory plant

  • Sara E. Scanga


Gap-dependent species are typically understood to have higher population growth rates (λs) when they are exposed to higher light transmittance. I investigated the relationship between both diffuse light and direct light transmittance and λ for the gap-dependent plant Trollius laxus using 5 years of data from 20 subpopulations (11 in created, experimental canopy gaps; 9 in intact canopy control areas). There was a nonlinear (unimodal) relationship between diffuse light and λ for T. laxus under the wide range of light levels encountered at the gap and control subpopulations [4–58 % diffuse photosynthetic photon flux density (PPFD)]. There was no relationship between direct light and λ. However, in the gaps, where light levels were generally greater than 20 % PPFD, both diffuse light and direct light had strong negative linear relationships with λ. Therefore, under wide-ranging light regimes, plant populations may show complicated, nonlinear responses to gap formation. Furthermore, gap-dependent plant populations may even decline in the brightest gaps. These results demonstrate that future studies on forest plant population dynamics should strive to include populations from a wide variety of light regimes, and avoid broadly categorizing light regimes as simply “gap” or “non-gap.”


Demographic change Gap-dependent species Matrix population models Plant population and community dynamics Rich fen Woodland herbs 



I thank J. P. Gibbs, K. L. Hajek, E. B. Harper, T. R. Horton, K. N. Jones, D. J. Leopold, S. V. Stehman, and several anonymous reviewers who improved the manuscript with their comments. I also thank Utica College for providing funding that supported the development of this publication.

Supplementary material

11258_2014_344_MOESM1_ESM.doc (175 kb)
Supplementary material 1 (DOC 175 kb)


  1. Ackerly DD, Bazzaz FA (1995) Seedling crown orientation and interception of diffuse radiation in tropical forest gaps. Ecology 76(4):1134–1146CrossRefGoogle Scholar
  2. Anderson KL, Leopold DJ (2002) The role of canopy gaps in maintaining vascular plant diversity at a forested wetland in New York State. J Torrey Bot Soc 129(3):238–250CrossRefGoogle Scholar
  3. Bedford BL, Walbridge MR, Aldous A (1999) Patterns in nutrient availability and plant diversity of temperate North American wetlands. Ecology 80(7):2151–2169CrossRefGoogle Scholar
  4. Bliss P (1985) Element steward abstract for Trollius laxus ssp. laxus—spreading globeflower. The Nature Conservancy, BostonGoogle Scholar
  5. Canham CD, Burbank DH (1994) Causes and consequences of resource heterogeneity in forests: interspecific variation in light transmission by canopy trees. Can J For Res 24:337–349CrossRefGoogle Scholar
  6. Canham CD, Denslow JS, Platt WJ, Runkle JR, Spies TA, White PS (1990) Light regimes beneath closed canopies and tree-fall gaps in temperate and tropical forests. Can J For Res 20:620–631CrossRefGoogle Scholar
  7. Caswell H (2001) Matrix population models: construction, analysis, and interpretation, 2nd edn. Sinauer Associates, Inc., SunderlandGoogle Scholar
  8. Chazdon RL, Pearcy RW (1991) The importance of sunflecks for forest understory plants. Bioscience 41(11):760–766CrossRefGoogle Scholar
  9. Cipollini ML, Whigham DF, O’Neill J (1993) Population growth, structure, and seed dispersal in the understory herb Cynoglossum virginianum: a population and patch dynamics model. Plant Species Biol 8:117–129CrossRefGoogle Scholar
  10. Cipollini ML, Wallace-Senft DA, Whigham DF (1994) A model of patch dynamics, seed dispersal, and sex ratio in the dioecious shrub Lindera benzoin (Lauraceae). J Ecol 82:621–633CrossRefGoogle Scholar
  11. Clearwater MJ, Gould KS (1995) Leaf orientation and light interception by juvenile Pseudopanax crassifolius (Cunn.) C. Koch in a partially shaded forest environment. Oecologia 104:363–371CrossRefGoogle Scholar
  12. Collins BS, Pickett STA (1988) Demographic responses of herb layer species to experimental canopy gaps in a northern hardwoods forest. J Ecol 76:437–450CrossRefGoogle Scholar
  13. Collins BS, Dunne KP, Pickett STA (1985) Responses of forest herbs to canopy gaps. In: Pickett STA, White PS (eds) The ecology of natural disturbance and patch dynamics. Academic Press, Inc., OrlandoGoogle Scholar
  14. Elderd BD, Doak DF (2006) Comparing the direct and community-mediated effects of disturbance on plant population dynamics: flooding, herbivory and Mimulus guttatus. J Ecol 94:656–669CrossRefGoogle Scholar
  15. Federer CA, Tanner CB (1966) Spectral distribution of light in the forest. Ecology 47(4):555–560CrossRefGoogle Scholar
  16. Frazer GW, Canham CD, Lertzman KP (1999) Gap light analyzer (GLA), version 2.0: imaging software to extract canopy structure and gap light transmission indices from true-colour fisheye photographs. Simon Fraser University and the Institute of Ecosystem Studies, Burnaby, British Columbia and Millbrook, New YorkGoogle Scholar
  17. Freeman S (2011) Biological science. Benjamin Cummings, San FranciscoGoogle Scholar
  18. Jacquemyn H, Brys R, Jongejans E (2010) Seed limitation restricts population growth in shaded populations of a perennial woodland orchid. Ecology 91:119–129PubMedCrossRefGoogle Scholar
  19. Keddy PA (2000) Wetland ecology: principles and conservation. Cambridge University Press, CambridgeGoogle Scholar
  20. Lieffers VJ, Messier C, Stadt KJ, Gendron F, Comeau PG (1999) Predicting and managing light in the understory of boreal forests. Can J For Res 29:796–811CrossRefGoogle Scholar
  21. Lindborg R, Ehrlén J (2002) Evaluating the extinction risk of a perennial herb: demographic data versus historical records. Conserv Biol 16(3):683–690CrossRefGoogle Scholar
  22. Machado J-L, Reich PB (1999) Evaluation of several measures of canopy openness as predictors of photosynthetic photon flux density in deeply shaded conifer-dominated forest understory. Can J For Res 29:1438–1444CrossRefGoogle Scholar
  23. Mason CF, MacDonald SM (2002) Responses of ground flora to coppice management in an English woodland—a study using permanent quadrats. Biodivers Conserv 11:1773–1789CrossRefGoogle Scholar
  24. Middleton BA, Holsten B, van Diggelen R (2006) Biodiversity management of fens and fen meadows by grazing, cutting and burning. Appl Veg Sci 9:307–316CrossRefGoogle Scholar
  25. Moore MR, Vankat JL (1986) Responses of the herb layer to the gap dynamics of a mature beech-maple forest. Am Midl Nat 115(2):336–347CrossRefGoogle Scholar
  26. Paquette A, Bouchard A, Cogliastro A (2007) A less restrictive technique for the estimation of understory light under variable weather conditions. For Ecol Manag 242:800–804CrossRefGoogle Scholar
  27. Paratley RD, Fahey TJ (1986) Vegetation–environment relations in a conifer swamp in central New York. Bull Torrey Bot Club 113(4):357–371CrossRefGoogle Scholar
  28. Parfitt BD (1997) Trollius. In: Flora of North America Editorial Committee (ed) Flora of North America north of Mexico, vol 3. Oxford University Press, New YorkGoogle Scholar
  29. Pascarella JB, Horvitz CC (1998) Hurricane disturbance and the population dynamics of a tropical understory shrub: megamatrix elasticity analysis. Ecology 79(2):547–563CrossRefGoogle Scholar
  30. Pearcy RW (2007) Responses of plants to heterogeneous light environments. In: Pugnaire FI, Valladares F (eds) Functional plant ecology, 2nd edn. CRC Press, New YorkGoogle Scholar
  31. R Development Core Team (2008) R: a language and environment for statistical computing. Version 2.8.1. R Foundation for Statistical Computing, ViennaGoogle Scholar
  32. Reader RJ, Bricker BD (1992) Response of five deciduous forest herbs to partial canopy removal and patch size. Am Midl Nat 127(1):149–157CrossRefGoogle Scholar
  33. Roxburgh JR, Kelly D (1995) Uses and limitations of hemispherical photography for estimating forest light environments. N Z J Ecol 19(3):213–217Google Scholar
  34. Runkle JR (1992) Guidelines and sample protocol for sampling forest gaps. US Department of Agriculture, Forest Service, Pacific Northwest Research Station, PortlandGoogle Scholar
  35. Scanga SE (2009) Population ecology of the rare wetland plant Trollius laxus (Ranunculaceae). PhD Thesis, State University of New York College of Environmental Science and Forestry, SyracuseGoogle Scholar
  36. Scanga SE (2011) Effects of light intensity and groundwater level on the growth of a globally rare fen plant. Wetlands 31:773–781CrossRefGoogle Scholar
  37. Scanga SE, Leopold DJ (2010) Population vigor of a rare, wetland, understory herb in relation to light and hydrology. J Torrey Bot Soc 137:297–311CrossRefGoogle Scholar
  38. Scanga SE, Leopold DJ (2012) Managing wetland plant populations: lessons learned in Europe may apply to North American fens. Biol Conserv 148:69–78CrossRefGoogle Scholar
  39. Schleuning M, Huamán V, Matthies D (2008) Flooding and canopy dynamics shape the demography of a clonal Amazon understorey herb. J Ecol 96:1045–1055CrossRefGoogle Scholar
  40. Stubben C, Milligan B (2007) Estimating and analyzing demographic models using the popbio package in R. J Stat Softw 22:1–23Google Scholar
  41. Swanson DK, Grigal DF (1991) Biomass, structure, and trophic environment of peatland vegetation in Minnesota. Wetlands 11(2):279–302CrossRefGoogle Scholar
  42. The SAS Institute, Inc. (2003) SAS for Windows v. 9.1. SAS Institute, Inc., CaryGoogle Scholar
  43. Valverde T, Silvertown J (1997a) An integrated model of demography, patch dynamics and seed dispersal in a woodland herb, Primula vulgaris. Oikos 80:67–77CrossRefGoogle Scholar
  44. Valverde T, Silvertown J (1997b) A metapopulation model for Primula vulgaris, a temperate forest understorey herb. J Ecol 85:193–210CrossRefGoogle Scholar
  45. Valverde T, Silvertown J (1998) Variation in the demography of a woodland understorey herb (Primula vulgaris) along the forest regeneration cycle: projection matrix analysis. J Ecol 86:545–562CrossRefGoogle Scholar
  46. Van Calster H, Endels P, Antonio K, Verheyen K, Hermy M (2008) Coppice management effects on experimentally established populations of three herbaceous layer woodland species. Biol Conserv 141:2641–2652CrossRefGoogle Scholar
  47. Volis S, Bohrer G, Oostermeijer G, Van Tienderen P (2005) Regional consequences of local population demography and genetics in relation to habitat management in Gentiana pneumonanthe. Conserv Biol 19(2):357–367CrossRefGoogle Scholar
  48. Wood SN (2006) Generalized additive models: an introduction with R. Chapman and Hall/CRC Press, Boca RatonGoogle Scholar
  49. Yee TW, Mitchell ND (1991) Generalized additive models in plant ecology. J Veg Sci 2:587–602CrossRefGoogle Scholar
  50. Young DR, Smith WK (1983) Effect of cloudcover on photosynthesis and transpiration in the subalpine understory species Arnica latifolia. Ecology 64(4):681–687CrossRefGoogle Scholar

Copyright information

© Springer Science+Business Media Dordrecht 2014

Authors and Affiliations

  1. 1.Department of BiologyUtica CollegeUticaUSA

Personalised recommendations