100 Influential Papers - page 16

S ECT I ON TWO
COMMUN I TY AND ECOSYS T EM DYNAM I C S
23
Thompson, K., Band, S.R. & Hodgson,
J.G. (1993)
Seed size and shape predict persistence
in soil.
Functional Ecology, 7, 236–241.
I discovered this paper during preparation of
a journal club session at the Eidgenössische
Technische Hochschule Zürich, in a period when
I had just done a number of seed bank surveys. I
had a strong feeling that seed size was a key trait
for understanding the contrasting abundances
of seeds in the soil. Seed shape also looked like a
suitable candidate for explaining seed movement
into the soil. This paper used for the first time
a simple but effective approach for predicting
species-specific differences in persistence of the
soil seed bank. This was achieved by plotting
seeds of a range of British species in a two-
dimensional diagram based on seed mass and
variation of seed dimensions. In doing so the
authors could demonstrate that there was a
marked separation between species with large and
elongated seeds resulting in transient seed banks
compared with small and round seeds with high
persistence. This concept has later been tested
with several floras outside north-western Europe
with variable results.
Johannes Kollmann
2
Cole, B. C. (1983)
Assembly of mangrove ant communities:
patterns of geographical distribution.
Journal of Animal Ecology, 52, 339-347.
24
25
Cole, B. C. (1983)
Assembly of mangrove ant communities: colonization abilities.
Journal of Animal Ecology, 52, 349-355.
Combining studies on distribution, habitat suitability, social behaviour, caste
structure, colonizing ability, and ergonomics, Blaine Cole provided an unusually
compelling argument on how an ant community is assembled. Using small
mangrove islands in the Florida Keys, he generated experimentally mechanistic
assembly rules for the five species involved, noting the presence of two
competitively dominant species, termed Primary, others being less aggressive
and avoiding encounters with dominant species. These rules were partially
deterministic – competition and behaviour prevented coexistence of some
species – and partly stochastic – establishment of one of the Primary species
on an island precluded colonization by the other. This study exemplifies the
detailed nature of investigations needed to establish a convincing mechanistic
understanding involving coexistence of species in a natural setting. Even when
small islands and few highly aggressive species are examined, the richness of
factors impinging on assembly is impressive, suggesting that in other studies
the detection of pattern with deduced assembly rules, without mechanistic
studies, are too primitive to reliably interpret nature. The figure illustrates the
assembly of the ant communities with constraints on the presence or absence
of species and their coexistence. MSR denotes the minimum size requirement
needed for an ant species to persist on a certain island size.
Peter Price
16
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