100 Influential Papers - page 27

Tansley, A.G. (1917)
On competition between
Galium saxatile
L. (
G.
hercynicum
Weige) and
Galium sylvestre
Poll.
(
G.asperum
Schreb.) on different types of soil.
Journal of Ecology, 5, 173-179.
Early in the 20th Century, British plant ecologists were largely
concerned with vegetation description as evidenced by Tansley’s
Types
of British Vegetation
(1911). These studies raised questions over the
factors affecting plant distribution. The starting point for this paper
was Tansley’s observation that two
Galium
species had contrasting
distributions on the Carboniferous limestone with
G. saxatile
confined
to the loess soils and
G. sylvestre
(now
sterneri
) to the rendzinas even
when they were separated by as little as a few centimetres. Tansley
describes experiments undertaken outdoors in the Cambridge Botanic
Garden in 1911-17 to investigate the role of soil type and competition
between the species in determining this distribution. He concludes that
competition acted ‘through the direct suppression of the shoots of one
species by those of the other as the result of its more vigorous growth
on its preferred soil.’ The paper is important as the first ‘laboratory’
study designed to elucidate the factors affecting plant distribution in
Britain. It is the starting point for many later studies, notably those
designed to investigate the calcicole-calcifuge problem which later
became a major preoccupation of British plant ecologists. Tansley went
on to influence experimentation by many others, but this is the only
example of his direct involvement in such a study.
John A. Lee
52
Gause, G.F., Smaragdova, N.P. & Witt, A.A. (1936)
Further studies of interaction between predator and prey.
Journal of Animal Ecology, 5, 1-18.
Although several of his classic papers on tests of the Lotka-Volterra models of predator-prey relationships were published elsewhere, this
one is in a BES journal. These papers were seminal, not least because they raised questions about the applicability of the simple models
which stimulated their development for much of the 20th century. Gause’s experiments using
Paramecium
, yeasts and mites, led to
oscillations of predator and prey in which the prey was eventually eliminated. These were not analogous to those predicted by the models
because they arose from the organisms interaction with the heterogeneity of the habitat; itself an important finding. Models have become
much more sophisticated (see elsewhere in these accounts) but the occasions on which thorough experimental tests of them in the field or
even laboratory as here, are rare, and consequently the links between theoretical ecology and studies of wild systems can remain elusive.
Sometimes models can be accepted uncritically because they seem to describe reality but are very difficult to test experimentally. Gause led
the way in an attempt to do so, and it is salutary that his work stimulated better modelling and more realistic experiments (e.g. see Atkinson
and Shorrocks p.29) in classically iterative fashion.
John Whittaker
53
27
S P EC I E S I NT E RACT I ONS
6
51
Salisbury, E.J. (1929)
The biological equipment of species in relation
to competition.
Journal of Ecology, 17, 197-222.
Salisbury began with a quotation from Darwin’s
Origin of
Species
acknowledging that it is generally very difficult to
state precisely how one species outcompetes another, but
then took a positive view of such understanding as had
accumulated. He emphasized the often slight differences in
conditions that tip the balance between species, a lesson
lost on some experimenters of the late 20th century. He
showed that many ‘plants grow not where they would but
where they must’. Many halophytes, aquatics and plants
of summer-dry soils grow much larger on well-drained,
non-saline moist soils than on their native soils; a warning
to those who in the 1930s took a naïve approach to the
‘adaptations’ of plants to particular habitats. Salisbury
reviewed carefully competition between plants for light
and water, but then wrote ‘of all the biological features
that influence frequency, capacity for propagation and
dispersal must obviously be of prime importance’. Many
would dispute this assertion, at least for perennials, but
there is truth in the idea of significant competition between
plants at every stage of the life cycle, an idea that was lost
sight of in much theorization of the 1970s-1980s. Salisbury
pioneered collection of ‘the vital statistics of plants’, and
in that way anticipated the great
contribution of John Harper.
Peter Grubb
E J Salisbury
AG Tansley
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