Annemarie Nagle
Biology 112
11/18/05
R. H. Whittaker’s Consideration of Climax Theory and the Progression of Ecological Concepts
Leading up to its Composition and Following from its Publication
R. H. Whittaker’s 1953 paper published in the journal Ecological Monologues, titled A
consideration of climax theory: The climax as a population and pattern, was a reactionary piece
in response to decades of studies performed on the subject of climax and their subsequent
convolution and contradiction of the commonly held theories on the subject. Incorporating a
tremendous amount of ecological research and taking a fully comprehensive snapshot of the
confusion present in the scientific community, Whittaker provided an elegant synthesis of the
findings of his day and provided a solution to this confusion which attempted to bring together
deeply divided regions of the ecological scientific community (especially the European and
American ecologists) and unite and direct further research under a clarified and rigorous
definition of climax.
The development of the prevailing theories of monoclimax and polyclimax in the infancy
of the area of climax studies laid parameters for determination of the constitution of a climax
community. Traditional methods of identifying climax community included: “unity of the
dominant growth form, area of climax, physiogeography, soil maturity, upland position,
mesophytism, tolerance, and higher growth form.” (Whittaker 1953). However, given the
tremendous complexity of characterization and identification of what constitutes the climax of a
particular community, these simplistic theories were doomed to contradiction. The emergence of
anomalous observations in particular communities led ecologists preceding Whittaker to attempt
to expand and adapt these simplistic models to parameters which clearly deviated from their
explicit or implicit tenets. The result was a profusion of terms attempting to qualify these
observations, such as subclimax, fire climax, retrogressive climax, preclimax, biotic climax,
climactic climax, conclimax, and disturbance climax, among many others. All these varying
definitions for “climax” rendered the term impotent and ineffectual in the analysis of community
structure. Whittaker’s reactionary hypothesis sought to incorporate the phenomena such as
continuous disturbance, community dynamics, and seemingly retrogressive life forms that were
being described in presumably “climax” communities which could no longer fall under the
traditional conceptions of what would constitute a climax (especially the monoclimax, climactic
climax, and polyclimax theories). His Climax Pattern Hypothesis was a generalizing definition
he hoped would infuse climax theory with new meaning and usefulness in quantitative
community analysis. He defines his Climax Pattern Hypothesis as: “…a steady state of
community productivity, structure, and population, with the dynamic balance of its populations
determined in relation to its site.” (Whittaker 1953).
The genealogy of Whittaker’s climax theory, as evidenced by the vast amount of
literature cited in his paper, is quite complex. The origins of the climax concept of course lie in
the discovery of vegetative dynamics and the description of the phenomenon of succession.
Without these precursors, the idea that a community could reach a steady state after a period of
change over time could never have been conceived. Early scientists like Buffon, who described
the succession of poplars by beech trees in French forests in 1742 and Biberg who observed the
primary succession of lichens and mosses in 1749 paved the way for climax theory development
(Cowles 1911). Perhaps the initial conceptualization of climax can be traced back to the Dutch
ecologist Eugenius Warming, whose work in Brazil led him to publish one of the first papers
describing ecological succession in 1896 (Laroca 2002).
Indeed almost all of the early work done in successional ecology was done by European
ecologists, but it was the American ecologists who ran with this concept and from it formulated
the first definitions of what the endpoint, or climax of a particular community would be
(Whittaker 1953). Henry C. Cowles, an American ecologist who studied under Warming
focused on climactic differences in different areas of the United States as being the determining
factors for the vegetation found there. His classic studies on Lake Michigan dunes of the plant
life found at varying distances from the influences of heavy wind, sand scouring and burial, and
wave action and flooding attributed distributions solely to these factors (Cowles 1899). In
Cowles’ papers one can also see the development of certain “traditional” determinants of climax
that Whittaker mentions in his work, especially upland position and mesophytism (Cowles
1911).
Another key player in the development of climax theory was the American ecologist
Frederic E. Clements. Clements too attributed the features of the climax of a particular area to
the climactic conditions. His view was that the climate of an area could only dictate a single, or
monoclimax, and that devoid of human disturbance, the vegetation and associated animal life
would always converge upon this single structure. Clements’ work provided a structure and a
language for analyzing the different stages of a community presumably on its way towards its
climax. He presented a framework vocabulary of terms such as “subclimax,” “postclimax,” and
“panclimax” (among various others) to qualify ecosystems that did not fit the description of what
the single climax for that particular climactic zone should be (Clements 1936).
Another important player in the development of this theory was the work of Henry
Gleason. His assertion that it was entirely possible to have completely differently structured
communities experiencing identical climactic conditions and observations of the vegetative
composition of transition areas led him to formulate his hypothesis of individualistic association.
Under this hypothesis, plants distribute themselves according to the individualistic characteristics
and ranges of tolerance of each species (Gleason 1926). Climax structure could change over
time with changes in climate or soil composition, via loss or changes in the range of the
individual species composing it (Gleason 1939).
Gleason’s developments and those of many other ecologists whose publications did not
appear to fit into any of the established categories for definition of climax prompted Whittaker to
create a comprehensive listing of the current observations and to suggest his refined framework
for defining a climax. This subsequent research showed that Clements’ monoclimax was clearly
far too simplistic to describe actual phenomena. Obvious discontinuities in climax structure, the
recognition of vegetation structure as patchy and dynamic, the incorporation of site history, and
the realization that the monoclimax model dealt with challenges using semantics and avoided
true scientific investigation into the origin of these outliers in this research lead to Whittaker’s
discrediting of the monoclimax model (Whittaker 1953).
Whittaker’s synthesis and definition of climax as “a steady state of community
productivity, structure, and population, with the dynamic balance of its populations determined
in relation to its site” truly redirected the study of these communities following its publication
(Whittaker 1953). Focus has especially come to rest upon the dynamics of the climax, as
opposed to the earlier focus on its stability, to the extent that modern ecologists have even come
to question if the “climax” truly exists. A focus redirected towards the effects of site history on
climax composition, the rearrangement of climax structure due to human activity, and the effects
of invasive species and climate change are also developing areas of investigation.
A study published in 1972 by Botkin, Janak, and Wallis reported their creation of a
computer simulation of a climax community in Hubbard Brook experimental forest. The
authors’ definition and basis for this simulation was heavily based on the definition of climax
presented by Whittaker. The climax of their simulation is a combination of different
successional stages, various patterns of birth, death, and disturbance, and graded physical
conditions. In fact, their definition of climax as a “state [that] is best viewed as the most
probable state at any point in an area which has remained in a constant climate without major
catastrophe for a long time” may hint at the beginnings of the doubt among many ecologists if
the climax was even a definable or real entity (Botkin 1972). The development of a
computerized model for prediction of probable community structure was also highly important,
and progressive sophistications have made it a widely used method today.
Another highly important study was done in 1973 by Dale Taylor on the importance of
fire in maintaining the natural communities of Yellowstone National Forest. This study
ultimately helped fire-suppression oriented American forest managers to awaken to the necessity
of disturbance in maintaining the diversity of naturally fire maintained ecosystems. In this case
the “climax” of very low diversity lodgepole pine stands was rarely a natural occurrence (Taylor
1973).
Henry Horn (1974) published a paper only a year later that reexamined the concept of the
climax as a “stable” system and analyzed productivity of the climax community. Prior to this
publication, a climax community was considered “stable” due to the fact that it was self
replicating and resistant to invasion of lower successional species. However, Horn indicates that
if stability is analyzed through the lens of “resistance to perturbation,” late successional and
climax communities are the least stable. The time it takes for a late successional or climax
community to return to its original state after disturbance is much longer than that of early
successional ones. He also pointed out that tree senility and nutrient hoarding often led to
reductions in productivity (Horn 1974). Such developments have been key in shaping modern
forest management practices and the discovery of how to maximize production in forest
ecosystems.
As indicated earlier, many ecologists have come to the belief that the climax is simply a
novel, idealistic construction, and that it may not be an actual state. This idea comes out patently
in a 1984 paper by Wayne Sousa, in which disturbance in communities is examined extensively.
He proposes that, due to the fact that some form of disturbance often occurs before the presumed
time it takes to reach climax, that the climax is unattainable. Self reproducing stands may exist
only as an average and may not fit the framework of definition of climax (Sousa 1984).
Despite the fact that certain scientists doubt the validity of the climax theory, it is still
widely applied in the study of many different ecosystems, and the increasing power of
quantitative analytical techniques and computer modeling have added a new rigor to the
analyses. Koike modeled forest ecosystems of subalpine, cool and warm temperate, and
subtropical forests in Russia. The model of the climax community is being used to estimate the
possibility for invasive plant species to occupy the established forests (Koike 2001). Computer
generated models of climax structure have also been used recently in determining the best course
of management in disturbed rainforest ecosystems. Without the benefit of long-term scientific
observations of pre-disturbance community structure, projection climax models have helped
format conservation plans for forests in Malaysia (Ditzer 2000). Variations of climax models
have even been used to predict future effects of climate change on vegetation patterns on Earth.
Tausch, et. al. used information from past fluctuations in plant cover during ancient climate
changes as well as “the concepts of thresholds, multiple steady states, and multiple successional
pathways [which] are helpful in understanding the dynamic interrelationships between vegetation
and environmental changes” to model possible vegetation response to our world’s changing
climate (Tausch et al 1993).
Whether or not the true climax of a community is an attainable or real event, I believe
that with the increasing power of technology and applications like those discussed above, it will
be less and less essential to carry out time-consuming and drawn out studies when observing a
particular ecosystem. Our world is becoming increasingly analytically based, and the days of
ecologists walking around in the woods and writing down their observations are waning. As we
come more and more to want concrete “proof” of how things work, analytical models will
become increasingly important. Timeliness is not only essential in the fast paced scientific
climate of today, but is also of great importance when considering the role of human disturbance
on communities. As human influence on natural systems expands globally, it becomes far harder
to observe and document the structure and natural influences that once dictated the species
present in a particular area. I think our deepened understanding of the role of disturbance in
natural systems, thanks to Whittaker and the scientists who succeed him, will provide us with a
framework for future conservation measures and comprehension of subtle environmental
changes. On the other hand, due to conservation efforts and land use changes, some land is
returning to wilderness where it was once modified by humans. I think that a stronger focus on
site history and multiple successional fates will help us attain a better set of management
practices in returning the land to an original or at least functional state.
Literature Cited
Botkin, D.B.; Janak, J.F.; Wallis, J.R. 1972. Some ecological consequences of a computer
model of forest growth. The Journal of Ecology. 60(3): 849-872.
Clements, F.E. 1936. Nature and structure of the climax. The Journal of Ecology. 24(1): 252284.
Cowles, H.C. 1911. The causes of vegetative cycles. Botanical Gazette. 51(3): 161-183.
Cowles, H.C. 1899. The ecological relations of the vegetation on the sand dunes of Lake
Michigan. I geographical relations of the dune floras. Botanical Gazette. 27: 95-117.
Ditzer, T.; Glauner, R.; Forster, M.; Kohler, P.; Huth, A. 2000. The process-based stand growth
model Formix 3-Q applied in a GIS environment for growth and yield analysis in a
tropical rain forest. Tree Physiology. 20(5-6): 367-381.
Gleason, H.A. 1926. The individualistic concept of plant association. Bulletin of the Torrey
Botanical Club. 53(1): 7-26.
Gleason, H.A. 1939. The individualistic concept of plant association. American Midland
Naturalist. 21(1): 92-110.
Horn, H. S. 1974. The ecology of secondary succession. The Annual Review of Ecology and
Systematics. 5: 25-37
Koike, F. 2001. Plant traits as predictors of woody species dominance in climax forest
communities. Journal of Vegetation Science. 12(3): 327-336.
Laroca, S. and Orth, A.I. 2002. Melissocoenology: historical perspective, method of sampling,
and recommendations to the “Program of conservation and sustainable use of pollinators,
with emphasis on bees”(ONU). Ministry of Environment/Brasilia. 217-225.
Paine, R.T. 2002. Advances in ecological understanding: By Khunian revolution or conceptual
evolution? Ecology. 83(6): 1553-1559.
Sousa, W.P. 1984. The role of disturbance in natural communities. The Annual Review of
Ecology and Systematics. 15: 353-391.
Tausch, R.J.; Wigand, P.E.; Burkhardt, J.W. 1993. Viewpoint-Plant community thresholds,
multiple steady-states, and multiple successional pathways-legacy of the quaternary.
Journal of Range Mangagement. 46(5): 439-447.
Taylor, D.L. 1973. Some ecological implications of forest fire control in Yellowstone National
Park, Wyoming. Ecology. 54(6): 1394-1396.
Whittaker, R.H. 1953. A consideration of climax theory: The climax as a population and
pattern. Ecological Monographs. 25: 41-78.
Well researched! Good job with citations.
You set up the previous research and impact of your paper well.
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