Abstract
Plants often interact with antagonists such as herbivores or pathogens. Negative effects on individual plant performance are widely documented, but less is known about whether such effects translate into effects on population viability. In temperate forests, important herbivores include deer. During 2006–2009, I compared vital rates and population growth rates (calculated using integral projection models) between fenced exclosures and grazed control areas, using the perennial herb Phyteuma spicatum as a model species. Deer caused the largest damage to flowering individuals, removing about 24% of all inflorescences and 13% of the above-ground biomass. Only few vital rates seemed to be negatively affected by deer (mainly seed production) and this did not translate into effects on population growth rate. Contrary to expectations, population growth rates tended to be lower in the fenced exclosures in 1 year. This was likely caused by high-pathogen infestation rates, which negatively affected the probability of adult survival and growth. Population growth rate was more sensitive to changes in these vital rates than to changes in seed production. In summary, the results of this demographic study show that grazing effects may be small for long-lived herbs, and that negative effects on vital rates such as seed production may not always translate into effects on population growth rate. The findings also illustrate that other antagonists such as pathogens may be of greater relative importance for differences in population performance than herbivores.
Similar content being viewed by others
References
Augustine DJ, Frelich LE (1998) Effects of white-tailed deer on populations of an understory forb in fragmented deciduous forests. Conserv Biol 12:995–1004
Bermingham LH (2010) Deer herbivory and habitat type influence long-term population dynamics of a rare wetland plant. Plant Ecol 210:359–378
Bowers MA, Sacchi CF (1991) Fungal mediation of a plant-herbivore interaction in an early successional plant community. Ecology 72:1032–1037
Burdon JJ, Chilvers GA (1982) Host density as a factor in plant disease ecology. Annu Rev Phytopathol 20:143–166
Caswell H (2001) Matrix population models: construction, analysis, and interpretation, 2nd edn. Sinauer Associates, Sunderland
Colling G, Matthies D (2004) The effects of plant population size on the interactions between the endangered plant Scorzonera humilis, a specialised herbivore, and a phyto-pathogenic fungus. Oikos 105:71–78
Côté SD, Rooney TP, Tremblay J-P, Dussault C, Waller DM (2004) Ecological impacts of deer overabundance. Annu Rev Ecol Evol Syst 35:113–147
Ellner SP, Rees M (2006) Integral projection models for species with complex demography. Am Nat 167:410–428
Farrington SJ, Muzika R-M, Drees D, Knight TM (2009) Interactive effects of deer herbivory on the population dynamics of American ginseng. Conserv Biol 23:719–728
Fuller RJ, Gill RMA (2001) Ecological impacts of increasing numbers of deer in British woodland. Forestry 74:193–199
Garve E (2004) Rote Liste und Florenliste der Farn- und Blütenpflanzen in Niedersachsen und Bremen–5. Fassung, Stand 1.3.2004. Informationsdienst Naturschutz Niedersachsen 24:1–76
Gilbert GS (2002) Evolutionary ecology of plant diseases in natural ecosystems. Annu Rev Phytopathol 40:13–43
Hegland SJ, Rydgren K, Seldal T (2005) The response of Vaccinium myrtillus to variations in grazing intensity in a Scandinavian pine forest on the island of Svanøy. Can J Bot 83:1638–1644
Hegland SJ, Jongejans E, Rydgren K (2010) Investigating the interaction between ungulate grazing and resource effects on Vaccinium myrtillus populations with integral projection models. Oecologia 163:695–706
Knight TM (2004) The effects of herbivory and pollen limitation on a declining population of Trillium grandiflorum. Ecol Appl 14:915–928
Knight TM, Caswell H, Kalisz S (2009) Population growth rate of a common understory herb decreases non-linearly across a gradient of deer herbivory. For Ecol Manag 257:1095–1103
Kolb A (2005) Reduced reproductive success and offspring survival in fragmented populations of the forest herb Phyteuma spicatum. J Ecol 93:1226–1237
Kolb A (2008) Habitat fragmentation reduces plant fitness by disturbing pollination and modifying response to herbivory. Biol Conserv 141:2540–2549
Kolb A, Dahlgren JD, Ehrlén J (2010) Population size affects vital rates but not population growth rate of a perennial plant. Ecology 91:3210–3217
Kumar S, Shibata E (2007) Establishment and growth of coniferous seedlings in an altered forest floor after long-term exclusion of deer. J For Res 12:306–311
Maron JL, Crone E (2006) Herbivory: effects on plant abundance, distribution and population growth. Proc R Soc B 273:2575–2584
Martin TG, Arcese P, Scheerder N (2011) Browsing down our natural heritage: deer impacts on vegetation structure and songbird populations across an island archipelago. Biol Conserv 144:459–469
McGraw JB, Furedi MA (2005) Deer browsing and population viability of a forest understory plant. Science 307:920–922
Milner JM, Bonenfant C, Mysterud A, Gaillard J-M, Csányi S, Stenseth NC (2006) Temporal and spatial development of red deer harvesting in Europe: biological and cultural factors. J Appl Ecol 43:721–734
R Development Core Team (2010) R: A language and environment for statistical computing. R Foundation for Statistical Computing, Vienna. http://www.R-project.org/
Rooney TP, Gross K (2003) A demographic study of deer browsing impacts on Trillium grandiflorum. Plant Ecol 168:267–277
Rooney TP, Waller DM (2003) Direct and indirect effects of white-tailed deer in forest ecosystems. For Ecol Manag 181:165–176
Russell FL, Zippin DB, Fowler NL (2001) Effects of white-tailed deer (Odocoileus virginianus) on plants, plant populations and communities: a review. Am Midl Nat 146:1–26
Schmidt M, Ewald J, Fischer A, von Oheimb G, Kriebitzsch W-U, Schmidt W, Ellenberg H (2003) Liste der in Deutschland typischen Waldgefäßpflanzen. Mitteilungen der Bundesforschungsanstalt für Forst- und Holzwirtschaft Hamburg 212:1–34
Silvertown J, Franco M, Pisanty I, Mendoza A (1993) Comparative plant demography—relative importance of life-cycle components to the finite rate of increase in woody and herbaceous perennials. J Ecol 81:465–476
Snow AA, Whigham DF (1989) Costs of flower and fruit production in Tipularia discolor (Orchidaceae). Ecology 70:1286–1293
Springer YP (2009) Edaphic quality and plant-pathogen interactions: effects of soil calcium on fungal infection of a serpentine flax. Ecology 90:1852–1862
Syrjänen K, Lehtilä K (1993) The cost of reproduction in Primula veris: differences between two adjacent populations. Oikos 67:465–472
Wheeler BR (1997) Aspects of the ecology and conservation of the rare plant species Phyteuma spicatum L. (Campanulaceae) in the British Isles. Dissertation, University of Sussex
Wheeler BR, Hutchings MJ (2002) Phyteuma spicatum L. J Ecol 90:581–591
Witt JC, Webster CR (2010) Regeneration dynamics in remnant Tsuga canadensis stands in the northern Lake States: potential direct and indirect effects of herbivory. For Ecol Manage 260:519–525
Acknowledgments
I thank Marion Ahlbrecht, Katharina Barsch, Dirk Enters, Dietrich Kolb, Silke Lehmann, Dorit Mersmann, Anja Schnorfeil, Anne Weber, and Christiane Weiner for research assistance, and Johan Dahlgren, Martin Diekmann, and Johan Ehrlén for discussion and comments on earlier versions of this manuscript. I thank the land owners for access to their forests and the administrative district Stade for the permit to work in the nature reserve “Im Tadel.” The University of Bremen provided financial support (ZF-No. 02/801/05).
Author information
Authors and Affiliations
Corresponding author
Rights and permissions
About this article
Cite this article
Kolb, A. Differential effects of herbivory and pathogen infestation on plant population dynamics. Plant Ecol 213, 315–326 (2012). https://doi.org/10.1007/s11258-011-9978-z
Received:
Accepted:
Published:
Issue Date:
DOI: https://doi.org/10.1007/s11258-011-9978-z