A Phytogeographical Comparison of Lakes Baikal and Superior
Robert J. Liebermann, May 6, 1994


 The significance of oceans and seas on climate and phytogeography has been well documented.   The effects of smaller bodies of water, i.e. lakes, has been much less intensively studied.   Of prime importance to the phytogeographer specializing in these regions is the unique interactions between lakes, climate, and plant distribution; which have been shown to create, in association with other factors, an extremely varied and interesting flora.
 Lakes Baikal and Superior, the world's largest freshwater lakes, provide an interesting opportunity for documenting the effects of large lakes upon climate and examining the effects of this on plant distribution.   The comparison of phytogeographical conditions, in view of the global position of these two lakes, can serve to illustrate certain effects attributable to the limnoclimate, topography, overall species distribution, and many other factors involved in the vegetation of the areas at Lakes Baikal and Superior.

Purpose of this paper:

 Lakes, in particular, large lakes, have an area which is climatically directly affected by the body of water.   The focus of this study is upon the phytogeographic similarities and variations of these climatic influence areas at Lakes Baikal and Superior.   The purpose of this paper is to (1) show the phytogeographic conditions of the Lake Superior and Lake Baikal areas, and examine some of the main influences on this phytogeography, e.g., mainly macro- and microclimate in this paper, but also geology, topography, soils, and human influence, and  (2) to compare the occurrence of some important plant taxa and plant communities in the two areas, and suggest reasons for their differences and similarities.   The specific tool of measurement used for analysis will be the locus and ecology of plant communities and species within these areas.   Because the vegetation communities of the areas are exceedingly plastic and varied, i.e., complex, and because the influences of various forces on these communities are also extremely complex, it will be necessary to generalize, and to use representative species, genera, and vegetation associations, rather than cover a large number of variants  individually.   This paper is not intended to be a comprehensive study; however, it is intended to show that there is a great need for further work regarding this problem.



 The occurrences of plants at Lakes Baikal and Superior is dependent on many individual parameters of climate, soil, competing vegetation, disturbance, and countless others; hence it is not possible to fully explain in detail why the floras of these areas appear as they do in relation to each other.   However, based on the specific examples observed and documented in the literature, it is possible to draw upon several general observations and make a few conclusions.
 The first observation is that Lakes Baikal and Superior, like other large water bodies, have a marked influence on the surrounding climate, and that many of these climatic enhancements can strongly affect plant growth and distribution.
 The second is that a large number of plants do follow closely the presence of the lakes: some are conspicuously absent from the lake areas; some make range extensions toward the lakes; some follow only the shorelines at the lakes;  some are disjunct from distant locations at the lakes, and some are endemic and found nowhere else.
 A third observation is that both Lake Baikal and Lake Superior are located to a large extent in the northern forests, and within this circumboreal formation, a large number of plants and plant communities  have been shown to be identical in species or genera.
 The final of these observations is that the occurrence of plants at the lakes does not necessarily follow a regular pattern; while many areas such as islands and the rocky shores of Lake Superior have been found to be areas of disjunct or rare species, similar areas nearby may have normal vegetation patterns.   In addition, there may be features unrelated to limnoclimate which are sufficient phytogeographical "magnets" for rare species, such a feature is Ouimet Canyon near Lake Superior.
 Based on the observations above, inductive logic points toward the following:  Lakes Baikal and Superior, both with very large surface areas, volumes, and depths, have a marked limnoclimatic effect on the surrounding areas.   This limnoclimate greatly changes the normal climate in the area in which it occurs, and thus appear as climatic "islands" distinct from their surroundings.   These areas have very special phytoclimatic conditions which allow a number of plants to survive which are normally found elsewhere, while at the same time allowing many of the typically boreal or northern species to remain.    In these areas, variations in local conditions of climate, soil, topography, disturbance, vegetation, and others determine how strong the limnoclimatic factor will affect the occurrence of species and communities.   Therefore, the occurrence of specific vegetation types, while somewhat predictable is not entirely predictable.
 It seems evident, then, that the limnoclimatic influence areas of Lake Baikal and Lake Superior share many climatic and phytogeographical processes unique to large lakes and to the boreal forest,  as well, the two areas share a great many identical species and genera.   .   They are also different in several aspects, and these differences give important clues to the controls on plant distribution in such areas.   Further study of this area of phytogeography would be helpful in documenting these similarities and differences, and explore further the reasons for these, as well as perhaps helping to unite the human inhabitants of these areas as well.


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