Comparative Phytogeography of Caribou Island, Lake Superior, Canada
and Ushkanii Island, Lake Baikal, Russia
Robert Liebermann MS research prospectus, Geography Department, Western Michigan University, February 9, 1998
Thirty years ago The Theory of Island Biogeography by Robert MacArthur and Edward O. Wilson (1967) drew attention to the interesting biogeographical question of islands and their ecology and evolution.
An unusual variant that was not addressed by MacArthur and Wilson is large lake island biogeography. The biogeographical forces involved on such islands are distinct from those of oceanic islands examined in Mac Arthur and Wilson, and deserve serious study as natural laboratories, unlike any other, of population ecology and isolation biogeography. In addition, the study of these rare ecosystems is more important than ever to understand how they might be preserved as a part of the world's natural heritage.
Perhaps most intriguing are the islands of very large lakes of temperate climates, where the interactions of air over land and over water are most influential on local climate. Here the changing temperatures of the seasons are moderated by the thermal lag and physical properties of the water to produce a limnoclimate which is neither maritime nor completely continental. As a result, microclimatic conditions on these islands can simulate the climates of other regions, such as more northern or southern areas. It is these limnoclimatic conditions which are among the most important elements of lake island biogeography. Island age and method of colonization are often distinct in lake islands as well. In addition, islands of large lakes have their own interesting characteristics that bear closer attention, such as the biogeographical significance of having a mainland much closeroften connected by ice during winterthan those of oceans.
Islands in large lakes share some attributes, although slightly differently, with those of oceanic islands. Examples are fewer species per area than on the mainland, higher rates of endemism of taxa, and unique balances of ecology related to isolation and limited genetic diversity.
Unfortunately, very limited study has been made on the subject of islands in such large lakes. Previous research that has been done, though occasionally excellent, is frequently obscured in various published and unpublished formats, and rarely related to larger systems than local ones. In addition, much of the best work relates to Lake Baikal, and is available only in difficult to access Russian language sources.
My thesis research is a comparative phytogeographical study of the Ushkanii Islands, Lake Baikal, Buryatia, Russia, and the Caribou Islands, Lake Superior, Ontario, Canada. Emphasis is given to the effects of limnoclimate, dispersal barriers, habitat limitations and isolation as primary influences on large lake island phytogeography, and to the similarities in response of the islandson opposite sides of the hemisphereas indication of some of the principles of this type of phytogeography.
Two areas are examined in the study. The first is the Ushkanii Islands, also known as the Ushkanii Archipelago, situated at 53° 50' N, 108° 40' E, near the center of Lake Baikal approximately 10 km west of the east-central shoreline at Svyatoi Nos Peninsula. The Ushkanii Islands are comprised of the largest island, Bolshoi Ushkanii, which means "Big Ushkanii" and three smaller islands to the east: Tonkii, Kruglii, and Dolgii; which mean "tiny", "round", and "long", respectively.
The second site is Caribou Island and the very small nearby
Lighthouse Island and Gull Island. Caribou Island is situated
near the east-center of Lake Superior, approximately 55 km west of the
shoreline at Agawa Bay, near 47 ° 22' N, 85 ° 49' W.
There is limited previous study (frequently none at all) on several "key" themes of large lake island phytogeography, including limnoclimatically-influenced phytogeography, circumboreal phytogeography, as well as the subject of large lake island biogeography itself. This allows me to make an original contribution to the knowledge of these topics, with a larger goal of a continuing specialization in the study of the principles of boreal phytogeography and limnoclimate at large lakes.
Perhaps most important, however, is the significance of the sites. These two enigmatic areas are unique to the world. Although the Ushkanii Islands are now included in the Zabaikalskii National Park, Caribou Island, conversely, is privately owned.
Attempts to locate the current owners of Caribou Island by myself and the Ontario Government, although leading, have been unsuccessful. The island's fate is precarious. Caribou Island has been recommended by Ontario Government specialists as an area of natural and scientific interest (ANSI), and worthy of provincial acquisition and protection. It is imperative that this site be afforded the same degree of understanding and protection as Ushkanii on Baikal.
Because of limited previous study in phytogeography of islands in large lakes, important questions remain to be clarified. Some of those I explore are:
Because of the interdisciplinary nature of the project, a wide range of previous studies have been consulted to understand the nature of the islands. For the Ushkanii Islands particularly, there is a wealth of scientific literature available. For Caribou Island, the data are less extensive, though increased interest in recent years by a small "elite" of interested researchers has produced some important preliminary contributions. General literature on phytogeography relating to islands, the boreal forest, and circumboreal vegetation geography is excellent, if scattered. A necessarily abbreviated mention of some of the most useful studies on these themes follow.
Previously mentioned study addressed biogeography applied to oceanic islands (MacArthur and Wilson 1967) some of which is applicable to lake islands. Islands in large lakes, however, have been much less thoroughly studied as distinctive systems. Kevin Timoney's thesis (1980), though incomplete in many ways, addressed some of the interesting questions of species diversity and number on islands in Lake Nipigon. He found, as on oceanic islands, a positive relationship between island size and number of species, and an inverse relationship between distance from mainland shore and number of species. Brian Hazlett (1988) studied the variations and influences on vegetation of islands in northern Lake Michigan, and showed the importance of several factors to the phytogeography, including limnoclimate, distance from shore, geological origin and disturbance history.
Although a small number of botanical studies are available for selected islands in large lakes (particularly relevant to my research are those of M. Ivanova [Иванова 1969], and John Morton and Joan Venn  for Ushkanii and Caribou Islands, respectively), reports available vary greatly in scope and size. Furthermore, there is a conspicuous lack of study relating to more comprehensive areas, such as investigation of the principles of lake island phytogeography from multiple or distant sites, or frequently even comparison of areas studied with other lake islands.
One of the determining factors of the phytogeography of large lake islands is the influence of limnoclimate on vegetation. Nikolai Ladeishchikov (Ладейщиков 1982) gives us an excellent primer on the subject of limnoclimate; his various works give much original insight on the nature of limnoclimate from the scientist who first used the term.
The influence of limnoclimate on plant distribution is one area in particular where more study is needed, although several reports have given a tantalizing look. Those of Mikhail Vuikhristyuk (Выхристюк 1980), Nikolai Ladeishchikov and Valeri Molozhnikov (Ладейщиков & Моложников1989) and David Given and James Soper (1981) attest to the appeal of the topic.
Circumboreal phytogeography at a hemispherical scale has been well covered in the works of Eric Hultén (1958, 1964, 1968, 1971), showing the ranges of many taxa across several continents; the interesting patterns near several large lakes, such as Baikal and Superior are easily examined in his works. With the exception of Hultòn however, the comparative phytogeography of separated regions is an understudied topic. One noteworthy account, especially relating to the Lake Superior region, is Louis Agassiz's historic (1850) comparison of the plants of the north shore of Lake Superior with those of the Jura and Alps Mountains of his native Europe. James Larsen (1980, 1982) has written several informative primers on the boreal ecosystem, though their focus is mainly on North American areas. There is clearly a deficit in coverage of the circumboreal forest as a single, interactive system influenced by similar forces.
Investigations have been made to assess their phytogeographic conditions of the two sites. Collected data include plant taxa present; location, abundance, and distribution of vascular plants and bryophytes; fire and disturbance history; climatic data (such as temperature, precipitation, snow cover, wind, humidity, and cloud data); geological and topographic conditions; and land use and human history on the islands. Data sources include field research [collections, measurements, field notes, observations, and ground and air photographs], and secondary sources [mainly published and unpublished literature and personal consultation]. My own field studies provide me with original and up to date information necessary for the project, otherwise unobtainable. Also, in my field research I can compensate for differences in presence and completeness of data for the two sites, to better allow comparison on a similar "yardstick". Examples of significant primary field data are the first comprehensive bryophyte collections on the islands, observations of change (such as due to fire or other disturbance) since the most recent literature, and new observations on the ecology and landscape of the islands. It is impossible to have an adequate understanding of the islands without this firsthand experience and knowledge with which to evaluate the collected data. Taxonomy of plant names are standardized; this is particularly important for the Ushkanii data, which are over 25 years old. Already accepted classification schemes of vegetation, climate, soils, etc. are used as much as possible (one area which is not lacking in plant geography is classification).
Thesis sections include introduction; research design; previous study relating to the topic; history, present use, vegetation, animal life, climate and limnoclimate, geology, topography, soils, disturbance, conservation and management recommendations for the islands; discussion and comparison of the flora and phytogeography, and conclusions. Geographical setting of the sites appropriate to facilitate understanding of the complex biogeographical conditions on the islands are discussed, and emphasis is placed on "indicator" taxa such as arcto-alpine, southern and steppe plant species, to show the phytogeographical patterns and indicate some possible influences on these. Comparative analyses of the florÔ and climates is included; discussion addresses possible reasons for their occurrences, differences and similarities. Descriptive data is incorporated into the text and appendices, as appropriate. Literature sections include all English and Russian language literature consulted during the research. Appendices include vascular plant taxa of the islands and their ecological conditions; tables and maps of vegetation, climate and other geographic features, and information on specialized terms and Russian author and place names.
The research histories of the two sites are markedly different. Little previous scientific research has been conducted on Caribou Island. Conversely, the political and economic prestige afforded Soviet science has resulted in a large and varied amount of data concerning the Ushkanii Islands and Lake Baikal in the Russian Language. I have been unable to find, either in Russian or English, any studies of the similarities in the florÔ of any region of these two "world's largest lakes", despite their similar geographies. With a good knowledge of previous research conducted at both lakes and elsewhere relating to the topic, I am integrating these studies in my work.
I have been, from afar, investigating Caribou Island since 1990, and the Ushkanii Islands since 1993. During my fourth visit to the post-Soviet states, and my second to Lake Baikal, from May to September 1995, I conducted literature and field research at Lake Baikal, including one month on the Ushkanii Islands, as the first phase of field study of my thesis project. I visited Caribou Island during June and July of 1996 to conduct similar investigations to those of 1995 on Baikal. I have a comprehensive resource of literature, professional advice, field notes, plant collections, photographs, and other data for my research. The final task of writing the thesis to produce a useful and interesting study is nearing completion.
There are many possibilities to continue my research of large lake islands, to expand what I have learned at Caribou and Ushkanii. Some areas I am interested in are a comparison of Caribou Island with two nearly identical islands, Leach and Montreal Islands, which are east of Caribou Island, but very close to the mainland shore. This would provide a good study of the importance of distance on phytogeography of the islands, and I have proposed such a study to the administration of Lake Superior Provincial Park, in which leach and Montreal Islands are situated. There are other islandsand shoreline areasof Baikal and Superior as well which I believe would make good further comparisons with each other and interesting individual studies on the effects of large lakes on phytogeography. Areas on other large lakes likewise lend themselves to such study. One area of note is Lake Nipigon, a large lake directly north of Lake Superior. Nipigon is literally "chocked full" of islands, with a great diversity of size, distance from mainland, and disturbance history. The lake lies in important east-west and north-south floristic transitions, and might be expected to have many interesting botanical disjuncts. Very little terrestrial ecological study has been carried out at Nipigon, and there is clearly a great potential for island biogeography and lakeshore phytogeography studies there.
Timeline of research progress:
The literature section has been deleted from this version of the prospectus to save space. It will be supplied if requested.