100 Influential Papers - page 15

COMMUN I TY AND ECOSYS T EM DYNAM I C S
Gross, K.L. (1984)
Effect of seed size and growth form on seedling establishment of 6 monocarpic perennial plants.
Journal of Ecology, 72, 369-387.
This seminal study is based on a comparative experiment, in which Gross measured the relative growth rate (RGR, mg g-1 day-1) of six
monocarpic herbs that share basal leaves but span more than two orders of magnitude in seed size. When plants were grown on bare soil,
with or without litter, RGR decreased with seed size within and across species. When grown with a competitor, plants instead displayed an
increase in RGR with seed size. These context-specific differences in RGR – combined with the usual advantages in seed number for smaller-
seeded species at a given reproductive effort – have profound implications, suggesting that competition should favour small seeds in fugitive
species that establish in recent disturbances, and larger seeds in species that establish in more crowded microsites. This study confirmed
some earlier ideas regarding the adaptive significance of seed size, but surprisingly demonstrated an RGR advantage for small seeds in
open microsites – a pattern supported by several later glasshouse studies. Gross’ investigation should be replicated on a grand scale, with
phylogenetically structured analyses and addition of several co-varying traits, and the basis of context-specific advantages in RGR sought in
the allometry of allocation to different organs and correlations with photosynthetic traits.
Tom Givnish
21
22
15
Thompson, K. & Grime, J.P. (1979)
Seasonal variation in the seed banks of herbaceous species in ten contrasting habitats.
Journal of Ecology, 67, 893–921.
Great progress in ecological research has been facilitated by new methods, as for example GIS technology or microsatellite markers, or new
theoretical concepts based on existing data. The paper by Thompson & Grime (1979) falls in the second category. Some field and laboratory
studies on seed banks had already been done before the 1970s, but the differences in seed longevity were described without consistent
theoretical basis. The suggested four categories of transient and persistent seed banks were based on seasonal variation in seed release,
germination and seed abundance in the soil. This relatively simple but elegant scheme was readily accepted by the ecological community
and stimulated thousands of empirical studies in almost all biomes and continents. The concept was attractive because it suddenly offered
a terminology for communicating species- and site-specific differences in seed bank characteristics. The significance of the paper is not
reduced by the fact that it later turned out to be not fully correct, and thus became replaced by a slightly modified set of seed bank types,
incidentally from the same research group [Thompson, Bakker & Bekker (1997)
The Soil Seed Banks of North West Europe: Methodology,
Density and Longevity
].
Johannes Kollmann
2
1...,5,6,7,8,9,10,11,12,13,14 16,17,18,19,20,21,22,23,24,25,...48