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Floral density, pollen limitation, and reproductive success in Trillium grandiflorum

  • Plant Animal Interactions
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Abstract

Decreases in floral density can disrupt mutualistic interactions between plants and their pollinators, and decrease reproductive success. I addressed the relationship between floral density and plant reproductive success using two experimental approaches: a pollen supplementation experiment in 12 populations of Trillium grandiflorum that naturally varied in floral density, and a transplant experiment in which floral density was manipulated in plots at four experimental sites. In the pollen supplementation experiments, the degree of pollen limitation, in terms of fruit set and seed set, decreased with floral density. Further, in the experimental sites, plant reproductive success increased asymptotically with floral density. These results demonstrate the value of simultaneously conducting experiments in both experimental sites and natural populations to understand how population density influences plant reproductive success. Factors that reduce the density of this perennial herb, such as habitat fragmentation and herbivory by white-tailed deer (Odocoileus virginianus), should be expected to limit its reproduction.

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References

  • Agren J (1996) Population size, pollinator limitation, and seed set in the self-incompatible herb Lythrum salicaria. Ecology 77:1779–1790

    Google Scholar 

  • Allee WC, Emerson AE, Park O, Park T, Schmidt KP (1949) Principals of animal ecology. Saunders, Philadelphia, Penn.

  • Anderson RC (1994) Height of white-flowered trillium (Trillium grandiflorum) as an index of deer browsing intensity. Ecol Appl 4:104–109

    Google Scholar 

  • Augustine DL, Frelich LE (1998) Effects of white-tailed deer on populations of an understory forb in fragmented deciduous forests. Conserv Biol 12:995–1004

    Google Scholar 

  • Baker AM, Barrett SCH, Thompson JD (2000) Variation of pollen limitation in the early flowering Mediterranean geophyte Narcissus assoanus (Amaryllidaceae). Oecologia 124:529–535

    Article  Google Scholar 

  • Broyles SB, Sherman-Broyles SL, Rogati P (1997) Evidence of outcrossing in Trillium erectum and Trillium grandiflorum (Liliaceae). J Hered 88:325–329

    Google Scholar 

  • Buchmann SK, Nabhan GP (1996) The forgotten pollinators. Island, Washington D.C.

  • Byers DL, Meagher TR (1992) Mate availability in small populations of plant species with homomorphic sporophytic self-incompatibility. Heredity 68:353–359

    Google Scholar 

  • Campbell DR (1986) Predicting plant reproductive success from models of competition for pollination. Oikos 47:257–266

    Google Scholar 

  • Carlsson-Graner UT, Elmqvist J, Agren J, Gardfjell H, Ingvarsson P (1998) Floral sex ratios, disease and seed set in dioecious Silene dioica. J Ecol 86:79–91

    Article  Google Scholar 

  • Case FW Jr, and Case RB (1997) Trilliums. Timber, Portland, Or.

  • Courchamp F, Clutton-Brock T, Grenfell B (1999) Inverse density dependence and the Allee effect. Trends Ecol Evol 14:405–410

    Google Scholar 

  • Dieringer G (1992) Pollinator effectiveness and seed set in populations of Agalinis strictifolia (Scrophulariaceae). Am J Bot 79:1018–1023

    Google Scholar 

  • Dudash MR, Fenster CB (1997) Multiyear study of pollen limitation and cost of reproduction in the iteroparous Silene virginica. Ecology 78:484–493

    Google Scholar 

  • Feinsinger P, Murray G, Kinsman S, Busby WH (1986) Floral neighborhood and pollination success in four hummingbird-pollinated cloud forest plant species. Ecology 67:449–464

    Google Scholar 

  • Fritz A-L, Nilsson LA (1994) How pollinator-mediated mating varies with population size in plants. Oecologia 100:451–462

    Google Scholar 

  • Goodwillie C (2001) Pollen limitation and the evolution of self-compatibility in Linanthus (Polemoniaceae). Int J Plant Sci 162:1283–1292

    Article  Google Scholar 

  • Griffin SR and Barrett SCH (2002). Factors affecting low seed:ovule ratios in a spring woodland herb, Trillium grandiflorum (Melanthiaceae). Int J Plant Sci 163:581–590

    Article  Google Scholar 

  • Groom MJ (1998) Allee effects limit population viability of an annual plant. Am Nat 153:487–496

    Article  Google Scholar 

  • Hackney EE, McGraw JB (2001) Experimental demonstration of an Allee effect in American ginseng. Conserv Biol 15:129–136

    Article  Google Scholar 

  • Hilborn R, Mangel M (1997) The ecological detective: confronting models with data. Princeton University Press, Princeton, N.J.

    Google Scholar 

  • House SM (1993) Pollination in a population of dioecious rain forest trees. Oecologia 96:555–561

    Google Scholar 

  • Irwin RE (2000) Morphological variation and female reproductive success in two sympatric Trillium species: Evidence for phenotypic selection in Trillium erectum and Trillium grandiflorum (Liliaceae). Am J Bot 87:205–214

    Google Scholar 

  • Irwin RE (2001) Field and allozyme studies investigating optimal mating success in two sympatric spring-ephemeral plants, Trillium erectum and T. grandiflorum. Heredity 87:178–189

    Google Scholar 

  • Jules ES (1998) Habitat fragmentation and demographic change for a common plant: Trillium in old-growth forests. Ecology 79:1645–1656

    Google Scholar 

  • Kalisz S, Hanzawa FM, Tonsor SJ, Thiede DA, Voigt S (1999) Ant-mediated seed dispersal alters pattern of relatedness in a population of Trillium grandiflorum. Ecology 80:2620–2634

    Google Scholar 

  • Karrenberg S, Jensen K (2000) Effects of pollination and pollen source on the seed set of Pedicularis palustris. Folia Geobot 35:191–202

    Google Scholar 

  • Klinkhamer PGL, de Jong TJ (1990) Effects of plant size, plant density and sex differential nectar reward on pollinator visitation in the protandrous Echium vulgare (Boraginaceae). Oikos 57:399–405

    Google Scholar 

  • Knight TM (2003a) Effects of herbivory and its timing across populations of Trillium grandiflorum (Liliaceae). Am J Bot 90:1207–1214

    Google Scholar 

  • Knight TM (2003b) The effects of herbivory and pollen limitation on the population dynamics of Trillium grandiflorum. PhD thesis, University of Pittsburgh, Penn.

  • Kunin WE (1993) Sex and the single mustard: Population density and pollinator behavior effects on seed-set. Ecology 74:2145–2160

    Google Scholar 

  • Kunin WE (1997a) Population biology and rarity: On the complexity of density-dependence in insect-plant interactions. In: Kunin WE, Gaston KJ (eds) The biology of rarity: causes and consequences of rare-common differences. Chapman and Hall, London, pp 150–169

  • Kunin WE (1997b) Population size and density effects in pollination: Pollinator foraging and plant reproductive success in experimental arrays of Brassica kaber. J Ecol 85:225–234

    Google Scholar 

  • Larson BMH, Barrett SCH (1999) The ecology of pollen limitation in buzz-pollinated Rhexia virginica (Melastomataceae). J Ecol 87:371–381

    Google Scholar 

  • Mitchell RJ (1997) Effects of pollination intensity on Lesquerella fendleri seed set: Variation among plants. Oecologia 109:382–388

    Article  Google Scholar 

  • Moody-Weis JM, Heywood JS (2001) Pollination limitation to reproductive success in the Missouri evening primrose, Oenothera macrocarpa (Onagraceae). Am J Bot 88:1615–1622

    Google Scholar 

  • Mustajarvi K, Siikamaki P, Rytkonen S, Lammi A (2001) Consequences of plant population size and density for plant-pollinator interactions and plant performance. J Ecol 89:80–87

    Article  Google Scholar 

  • Ramsey M, Vaughton G (2000) Pollen quality limits seed set in Burchardia umbellata (Colchicaceae). Am J Bot 87:845–852

    Google Scholar 

  • Sage TL, Griffin SR, Pontieri V, Drobac P, Cole WW, Barrett SCH (2001) Stigmatic self-incompatibility and mating patterns in Trillium grandiflorum and Trillium erectum. Ann Bot 88:829–841

    Article  Google Scholar 

  • Santandreu M, Lloret F (1999) Effect of flowering phenology and habitat on pollen limitation in Erica multiflora. Can J Bot 77:734–743

    Article  Google Scholar 

  • Stephens PA, Sutherland WJ (1999) Consequences of the Allee effect for behaviour, ecology and conservation. Trends Ecol Evol 14:401–405

    Google Scholar 

  • Stephenson AG (1981) Flower and fruit abortion: Proximate causes and ultimate functions. Annu Rev Ecol Syst 12:253–279

    Google Scholar 

  • Steven JC, Peroni PA, Rowell E (1999) The effects of pollen addition on fruit set and sex expression in the andromonoecious herb Horsenettle (Solanum carolinense). Am Midl Nat 141:247–252

    Google Scholar 

  • Steven JC, Rooney TP, Boyle OD, Waller DM (2003) Density-dependent pollinator visitation and self-incompatibility in upper Great Lakes populations of (Trillium grandiflorum). J Torrey Bot Soc 130:23–29

    Google Scholar 

  • SYSTAT (1999) SYSTAT version 9. SPSS Institute, Chicago, Ill.

  • Widen B (1993) Demographic and genetic effects on reproduction as related to population size in a rare, perennial herb, Senecio integrifolius. Biol J Linn Soc 50:179–195

    Article  Google Scholar 

Download references

Acknowledgments

I thank T-L. Ashman, A. Case, J. Chase, S. Kalisz, R. Relyea, J. Steets and S. Tonsor for discussions and comments, J. Butzler, J. Chase, J. Dunn and J. Kauffman for help in the field, and B. Casper and two anonymous reviewers for helpful suggestions. This research was supported by McKinley and Darbarker research funds, Botany in Action (Phipps Conservatory and Botanical Garden), the University of Florida Foundation, and the NSF (DEB-0105000). This is Pymatuning Laboratory of Ecology Publication 142.

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  1. Tiffany M. Knight

    Present address: Department of Zoology, University of Florida, 111 Bartram Hall, P.O. Box 118525, Gainesville, FL 32611–8525, USA

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  1. Department of Biological Sciences, University of Pittsburgh, Pittsburgh, PA 15260, USA

    Tiffany M. Knight

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Correspondence to Tiffany M. Knight.

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Knight, T.M. Floral density, pollen limitation, and reproductive success in Trillium grandiflorum . Oecologia 137, 557–563 (2003). https://doi.org/10.1007/s00442-003-1371-8

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