Ecological Succession and Community Dynamics - Ecological Systems - page 41

Attempts at Synthesis: Connell and Slatyer
The persistent dichotomy represented by Clementsian versus Gleasonian views of
succession has consistently invited attempts to synthesis toward a unified concept.
J.H. Connell and R.O. Slatyer [ 19 ] developed a synthesis that emphasized the
individual attributes of plants and their feedback with their environment. Clementsian
succession was a special case, which they called the “Facilitation Model” ( Fig. 3.4 ).
The replacement patterns in the Connell and Slatyer model were for sets of species,
which also implies to some degree a replacement of one community with another,
which also is more of a Clementsian concept. Succession was driven by transfers from
one set of species as the facilitation model in which succession as arises from the
resident species at a location encouraging the colonization of a subsequent set of
species, as the tolerance model in which the resident set of species are relatively
neutral in their interaction with other species, or as the inhibition model in which the
resident species block the colonization by other species ( Fig. 3.4 ).
Attempts at Synthesis: E.P. Odum
Eugene Pleasants Odum was a significant figure in what Robert McIntosh called the
rise of ecosystems science. In 1953, he wrote the first modern ecology textbook,
[ 40 ] which was the standard text for an emerging formulation of ecology as a formal
academic discipline. He and his brother H.T. Odum were instrumental in the use of
energy transfers in ecosystems (ecological energetics) as a common currency for
comparing ecosystems with one another. As the sons of a crusading sociologist,
H.W. Odum, the two Odum brothers were drawn to include “human ecosystems” in
their studies, particularly the energetics of human society and its interactions with
the natural ecosystems. The impact of ecological energetics on ecology was pro-
found in that it promoted large-system intercomparisons. The International
Biological Programme, the first “big picture” synoptic study of ecosystems used
ecological energetics as an organizing principle for projects that compared forests,
grasslands, and other biomes, worldwide. These comparisons were often made
using “compartment models,” diagrams in which the transfers of energy in units
of such as Kcalm 2 year 1 were indicated by arrows connecting boxes which
expressed the integral of the arrows such as Kcalm 2 . Compartment models were
easily transformed into ordinary differential equations for model projections
Also in the 1950s and 1960s, the United States Atomic Energy Commission
(USAEC) sponsored a large program studying the movement of radioactive
isotopes in natural environments including whole ecosystem experiments and direct
measurements of rates of transfer of isotopes through natural environments [ 41 ].
Large, linear compartment models developed in pharmacology [ 42 ], and used in
ecological energetics were developed to predict the ecological transfer of these
materials. There were several advantages to such linear models. They (even for
complex linear models) can be solved at equilibrium by algebraic manipulations, an