tolerance-fecundity trade-off and the maintenance of diversity in seed size

Seed size commonly varies by five to six orders of magnitude among coexisting plant species, a pattern ecologists have long sought to explain. Because seed size trades off with seed number, small-seeded species clearly have the advantage in fecundity, but what is the countervailing advantage of larg...

Full description

Saved in:
Bibliographic Details
Published in:Proceedings of the National Academy of Sciences - PNAS 2010-03, Vol.107 (9), p.4242-4247
Main Authors: Muller-Landau, Helene C., Levin, Simon A.
Format: Article
Language:English
Subjects:
Biological Sciences
Botany
competition colonization tradeoff
dimensions
Fecundity
Fertility
Flowers & plants
Habitat destruction
Habitats
Plant communities
plant competition
plant ecology
Plant Physiological Phenomena
plant reproduction
Plants
seed productivity
Seed size
Seeds
Species
Species diversity
Species Specificity
Stress tolerance
Synecology
Citations: Items that this one cites
Items that cite this one
Online Access:Get full text
Tags: Add Tag
No Tags, Be the first to tag this record!
Description
Summary:Seed size commonly varies by five to six orders of magnitude among coexisting plant species, a pattern ecologists have long sought to explain. Because seed size trades off with seed number, small-seeded species clearly have the advantage in fecundity, but what is the countervailing advantage of large seeds? Higher competitive ability combined with strong competitive asymmetry can in theory allow coexistence through a competition-colonization trade-off, but empirical evidence is inconsistent with this mechanism. Instead, the key advantage of large seeds appears to be their tolerance of stresses such as shade or drought that are present in some but not all regeneration sites. Here I present a simple, analytically tractable model of species coexistence in heterogeneous habitats through a tolerance-fecundity trade-off. Under this mechanism, the more tolerant species win all of the more stressful regeneration sites and some of those that are less stressful, whereas the more fecund species win most but not all of the less stressful sites. The tolerance-fecundity trade-off enables stable coexistence of large numbers of species in models with and without seed limitation. The tolerance-fecundity mechanism provides an excellent explanation for the maintenance of diversity of seed size within plant communities and also suggests new hypotheses for coexistence in animal and microbial communities.
ISSN:0027-8424
1091-6490
DOI:10.1073/pnas.0911637107