| BEN |
| BOTANICAL ELECTRONIC NEWS |
|---|
| ISSN 1188-603X |
| No. 335 September 29, 2004 | aceska@victoria.tc.ca | Victoria, B.C. |
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The Seaside Centipede Lichen (Heterodermia sitchensis Goward & Noble) is one of western North America's true lichenological rarities. At the time of its description in the mid 1980s, it was known from only two sites worldwide, both located along the hypermaritime west coast of Vancouver Island (Goward 1984). One of these localities was subsequently lost to housing development, leaving only the type locality, which is in Pacific Rim National Park Reserve. A COSEWIC status report commissioned in 1994 led, a few years later, to H. sitchensis being designated as endangered in Canada (Goward 1996). In 2001, Parks Canada initiated further studies on this lichen, prompted by a mandated requirement to develop recovery plans for rare species occurring within its jurisdiction. During the following two summers, I scoured Pacific Rim Park and surrounding areas for H. sitchensis, and at the same time attempted to learn what I could about its distribution and ecology. What now follows is some of what was learned (see also Goward & Wright 2003). The assistance of Ken Wright, as well as that of Brian Reader and other Parks Canada staff has been much appreciated.
There are 92 known species of Heterodermia in the world, most at tropical and warm temperate latitudes. In North America we have 28 species, only 7 of which occur along the west coast north of California.
Heterodermia sitchensis is a semi-erect, cushion-forming, foliose lichen up to about 2 cm across. The lobes vary from short to longish, are 1-2 mm wide, and have long thin, marginal cilia that call to mind the legs of a centipede. The upper surface is pale milky greenish or bluish, except where interrupted by scattered whitish spots (maculae). Mature thalli usually have urn-shaped sexual fruiting structures (apothecia) near the lobe tips, these with prominent flaring rims that in turn bear powdery asexual reproductive propagules (soredia) on their inner surface. The lower surface is white and under the hand lens looks like matted cotton. This lichen could be confused with Physcia tenella, another tree-dwelling species with pale lobes and cilia-bearing lobe margins. In that species, however, the soredia are located on the undersides of the lobe tips, and the lower surface is hard and skinlike, not cottony.
You could say that Heterodermia sitchensis is a tree-dwelling lichen with refined tastes. For starters, it is very particular about location, being restricted to open (but not exposed) localities by the sea. And though I have searched for it by the sea on a wide array of host trees, it seems invariably to colonize only one: Sitka spruce (Picea sitchensis). What is more, not just any Sitka spruce will do, but it must be an aged Sitka spruce, or else a Sitka spruce that's stressed and slow- growing. So likewise with its position in the canopy, which seems always to be within three or four metres of the ground. Here, moreover, it occupies small twigs less than about 1 cm in diameter and growing less than about 10 cm per year. Finally, only the defoliated portion of those twigs are colonized, the adjacent foliated portions perhaps being too young or too ecologically unstable.
The fact that Heterodermia sitchensis is confined to small twigs effectively defines it as an early colonizer, a pioneer species. And like other pioneer species, H. sitchensis is relatively short-lived. By my calculations, it must complete its life cycle by the time the portion of twig it occupies is ten years old; for by then its place on that twig will have been usurped by other, more aggressive lichens and bryophytes. This observation is probably key to its status as a rare species; for though H. sitchensis -- denizen of twigs -- needs to recolonize at frequent intervals, it appears to be woefully inefficient at doing so.
Whether the problem with successful colonization involves limitations of dispersal, or whether it stems from an inability to become established on its host twig is anybody's guess. Probably both. On the one hand, Heterodermia sitchensis depends for its dispersal on powdery soredia that develop near the lobe tips on the insides of tiny "urns." How these soredia can possibly escape from these urns to traverse the distance from one tree to another is unclear to me. Could it be the work of birds?
And on the other hand, Heterodermia sitchensis is physiologically ill-equipped to colonize conifer twigs in the first place. This is one of the key findings of my study, made in cooperation with Art Fredeen of the University of Northern British Columbia: H. sitchensis is a eutrophic species, requiring exceptionally high levels of nutrient enrichment. In the twigs studied, the enrichment came in the form of nitrogen (Goward & Fredeen, in prep.), which itself also came in two forms: uric acid and urea. The fact the same twigs, notwithstanding, registered a pH much higher than that of other twigs studied is a minor mystery still in need of solving.
Regardless of the actual details of bark chemistry, there is little doubt that nitrogen enrichment of one kind or another triggers the growth of Heterodermia sitchensis. To see this, you have merely to look where it grows. Directly below the perching sites of birds for one thing. Here bird droppings create vertical columns of enrichment ("guano falls") that can be traced lichenologically downwards to the forest floor. Another favoured habitat for H. sitchensis is sites adjacent to sea lion winter haulouts. The ability of nitrogen-rich aerosols to impregnate the bark of barnyard trees is well known, so why not seaside trees? Calciferous bedrock also appears to benefit H. sitchensis, possibly through the uptake of nutrients via the roots of trees. In this case, however, some additional source of nitrogen is apparently required, as for example the aforementioned columns of enrichment. Then there's the salutary influence of seabird colonies: the nesting sites of glaucous-winged gulls, pelagic cormorants, black oystercatchers, and pigeon guillemots all potentially provide nutrients sufficient to support H. sitchensis on nearby trees. Finally, one of the more intriguing sources of enrichment includes calcium-rich shell middens from old aboriginal village sites, though here again some supplementary source of nitrogen appears to be required.
Taken together, the above observations imply that the occurrence of Heterodermia sitchensis can be predicted on the basis of four broad environmental factors: 1) adjacency to the ocean; 2) Sitka spruce; 3) slow-growing twigs; and 4) nutrient enrichment. Only in sites where these four factors overlap is H. sitchensis likely to be found.
To date, I have recorded a total of 159 thalli of Heterodermia sitchensis from nine localities ranging from the Bamfield area in the south to Lawrence Island 75 km farther north. In most localities this species has been documented from only one or a few trees, though at least two hotspots are now known: one in the Broken Group Islands, and another on Florencia Island, just off Pacific Rim. Recently H. sitchensis has also been reported from coastal Oregon, where it grows on Cape Lookout (McHenry & Toensberg, 2002).
Despite its occurrence in nine localities, Heterodermia sitchensis should not be considered secure and of no concern to conservationists. On the contrary, its ecological status as a pioneer species imposes a requirement for frequent colonization, while its requirement for high levels of nutrient enrichment prevents successful establishment at most sites. Even during the two years of my study, I noted major albeit probably temporary declines in population size. What is more, nearly 70% of existing thalli are restricted to two small islands in Pacific Rim National Park Reserve. In my opinion, the small size of even these hotspots renders this species vulnerable to local disturbance.
[For Bruce McCune's key to the genus Heterodermia see: http://oregonstate.edu/~mccuneb/Heterodermia.pdf ]
From the dust jacket:
"The present General Volume covers topics of general interest such as Nordic floristic history, environment and vegetation, endemism, man's impact, and plant protection. Students of the Nordic flora will also welcome some chapters of handbook character: an annotated list of standard literature, a detailed account for the Nordic herbaria, and an extensive glossary including translation to Nordic languages."
The first chapter of the General Volume deals with the history of floristic surveys and publications of the area covered by the Nordic Flora: the Scandinavia (excluding Karelia and adjacent parts of Russia), Denmark, Iceland, Faroe Islands and Svalbard. This chapter describes the very roots of the modern systematic botany and phytogeography.
The core of this volume is a large chapter on Features of Nordic environment and vegetation (over 60 pages) that covers topics such as climate, quaternary geology and the major formations encountered in the area. The section on quaternary geology is one of the most interesting to the audience outside the "Norden". The terms such as "Yoldia Sea", "Ancylus Lake", and "Litorina Sea" - related to the different stages of the Baltic Sea - will ring the bells with every European botanist. They are well explained and illustrated in this book.
The chapters on The impact of man, Plant protection, Endemic plants in Norden follow this general description of environments and vegetation.
The last third of this book deals with technical aspects of the Flora Nordica series: Principles and conventions of the Nordic Flora, Standard literature, the list of Nordic herbaria, and the multilingual dictionary of Botanical terms.
Fifteen authors contributed to this volume. In spite of this number of authors, the book is well edited and the treatment of single topics is relatively well balanced. The volume is richly illustrated and meticulously designed. I would have preferred a different, more logical order of the chapters on endemic plants, human impact and plant protection (in this order). My conservationist heart of a conservationist found the photograph of about thirty people standing on the top of a palsa appalling. I would have liked to see a better review of the nunatack and refugia question than a single reference to a paper that dismissed this problem based on a highly mechanical, numerical analysis of the northern floras. I found it amusing that in the list of Nordic botanists, the Czech botanist Emil Hadac (see BEN # 311 for his obituary) ended up with two more given names formed of "Frantiskovy Lazne", the town where he was the director of a peat research institute for a short part of his professional career.
One feature that I found exceptional in the Flora Nordica volume 1 and 2 is their beautiful typographical design. I wanted to know how this was achieved and I received the following answer from Magdalena Agestam, The Bergius Foundation:
"The typography is the result of a teamwork, actually. It was based on the typography for Svensk Botanisk Tidskrift (designed in 1976 by Börje Brandt at Berlingska Boktryckeriet in Lund) - adjusted by the botanists in the Flora Nordica editorial group, through much discussion and testing, to quite a different content, context and size - and finally slightly adjusted again after some suggestions from Xtina Woots, librarian in Uppsala with a great interest in book design. (The General Volume needed a slightly different format; Xtina Woots was not consulted this time.)"
Do you know the joke that a camel is a horse designed by a committee? Surprisingly enough, in this particular case, the committee designed a real horse and a beautiful one indeed!
This present General Volume was reviewed by David F. Murray in the Flora of North America Newsletter see http://www.fna.org/FNA/Newsletter/Volume/V18n1.html
My review of Volume 2 was posted in BEN # 277 http://www.ou.edu/cas/botany-micro/ben/ben277.html and David F. Murray reviewed both Volume 1 and 2 in the Flora of North America Newsletter: http://www.fna.org/FNA/Newsletter/Volume/V17n1.html
In his review, David F. Murray wrote: "If you like floras, you'll love Flora Nordica. To Bengt Jonsell, Editor-in-Chief; Thomas Karlsson, Executive Editor; and to all the participants, I offer congratulations."
I fully agree with this statement.
I was shocked and flattered when I saw the excerpt of my review of the first edition of the "Alpine Plant Life" (BEN # 258) printed on the cover of this new edition. I have to repeat here that this book is the best modern treatment of 'functional ecology' of alpine plants that I have seen. The seeds that germinated with the Austrian IBP (International Biological Programme) contribution (Hoher Nebelkogel 3184 m") brought bore their fruits in this book after forty years after the IBP began. Christian Koerner projected those autecological approaches that were developed during the IBP studies onto the alpine vegetation worldwide.
Why the new edition so close soon after the first one? I suspect that the publisher, Springer-Verlag, underestimated the interest in and demand for this book, and demand for it and the first edition went out-of-print very quickly. The new edition, in hard copy book, costs less than the softcover copy version of the first edition and precisely one half of the cost of the first edition's hardcover version. This tells me that theis present print runing for this edition is much larger than that of the first edition. At the same time, this new edition added over 100 new references, new diagrams and revised and extended several chapters. I had a feeling that some parts were rewritten and translated anew, since I found them easier to read.
This book is an excellent summary and key to the study of plant-habitat relationships. I would say that is it biased towards single plants and their ecology. Alpine treelines are discussed in a special chapter, but the more general aspects, such as alpine vegetation per se and its synecology, are missing in this book. Consequently, the more general phytogeographical aspects of alpine vegetation, such as the anemo-orographic systems (see BEN # 260), or the old good "Gipfelphaenomen" (= the top of a mountain is usually floristically poorer than its slopes) are not mentioned at all. I already complained about that in my review of the first edition. As a nitpicking aside, the generic name of Castilleja is misspelled in this book.
The author is Professor of Botany at the University of Basel, Switzerland, and he is a co-editor of another two books published (or soon to be published) by the Springer-Verlag:
The Alpine Plant Life by Christian Koerner should be a compulsory reading for every plant ecologist. In my library it is right next to the Larcher's Physiological plant ecology that was also published by the Springer-Verlag (in its 4th edition in 2003).
EUROPE, ASIA, AUSTRALIA AND AFRICA
Kluwer Academic Publishers
Book Department.
PO Box 322
3300 AH Dordrecht
The Netherlands
Telephone 31-78-657-60-00
Fax 31-78-657-64-74
E-Mail: orderdept@wkap.nl
This book presents the first detailed survey, in English, of the forest vegetation of northeast Asia, a vast, mainly boreal or cool-temperate region that includes the Russian Far East (easternmost Siberia, Kamchatka, Sakhalin and Kuril Islands), Manchuria (northeastern China and adjacent), and northern Korea and Japan.
Vegetation descriptions were prepared by local and foreign vegetation scientists, partly from literature sources but also from local field experience, including the several Czech-Slovak botanical expeditions to North Korea during the 1990s. Regional integration is provided in chapters on physical conditions and biogeography, and in a chapter comparing vegetation syntaxa. Two methodologies are used: 1) Exploration and forest classification following the Sukachev school of forest types (Manchuria and Russian Far East); and 2) Forest classification by Zurich-Montpellier (Braun-Blanquet) methodology (Japan and North Korea). The book should be valuable to vegetation scientists, conservation biologists, and anyone interested in the regional vegetation and landscapes, including students.
Acknowledgements.
Preface.
This is a remarkable compendium on the forest vegetation of Northeast Asia. The two Czech editors of this volume (J. Kolbek and M. Srutek) took part in the Czech and Slovak expeditions to North Korea in the 1990s. The results of these expeditions are summarized in chapters 8 to 10 and in the main part of the chapter 11. In order to provide a broader context for their work within the general phytogeographic setting of Northeast Asia, they invited other vegetation scientists working in Northeastern Asia to contribute to this issue. Elgene Box, who is known for his interest in Northeast Asia, joined the editorial team and contributed to this issue as a co-author of the Introduction and the chapter on climate. (Elgene Box was the chief editor of a related collection of papers Vegetation science in forestry: global perspectives based on forest ecosystems of East and Southeast Asia published in 1995 by the Kluwer Academic Publishers.)
In the end, almost twenty authors contributed to this issue. With this number of authors one can expect quite a variation in approaches and methods. And indeed, the contribution by Qian et al. is a gross classification of what are essentially vegetation formations (defined by the dominant tree species); however, this approach seems to be appropriate since the treatment covers a large area and there is a lack of vegetation samples based on actual plots. Czech and Slovak contributions from North Korea, on the other hand, represent the other end of the scale. Their classification follows the Zurich-Montpellier methodology, and is built "from the bottom up" and based on vegetation samples (releves). Although the number of releves is not too large (244 releves), the result offers a good description of forest vegetation in North Korea. This classification incorporates works of South Korean botanists, such as J.-S. Song, who was a student of Japanese plant sociologist Akira Miyawaki who in turn was a student of Reinhold Tuexen in Germany). Contributions by Kolbek et al. from North Korea go far beyond the usual descriptive part of the Zurich-Montpellier methodology, and contain detailed information on forest soils and soil-vegetation relationships. The contribution by Okitsu summarizes the work of Japanese vegetation scientists, most of whom work using the methodology of the Zurich-Montpellier school.
In addition to these two approaches, Pavel Krestov, in his description of the Russian Far East vegetation, took yet a different approach. He based his classification on the Russian version of the Scandinavian vegetation study school. Krestov gives a good description of the techniques and terms he used and the reader can get a very good clear picture of the Far East vegetation from his article. It is interesting to note that the same Pavel Krestov published a typical Zurich-Montpellier _Phytosociological study of Picea jezonensis forests of the Far East (with Y. Nakamura, Folia Geobotanica 37: 441-473, 2002) - reprinted in the Opulus Press issue on Vegetation of circumboreal coniferous forests (for review of that collection of papers see BEN # 326). I enjoyed this paper and was the most interested in to reading that "the Braun-Blanquet approach [=Zurich-Montpellier school] could not be used [in the USSR] for political reasons." (I sense a similar bias against this school in North America from the proponents of the classification sponsored by the Nature Conservancy!)
The closing chapter on Comparison of forest syntaxa and types in Northeast Asia summarizes the vegetation using units and hierarchy defined by the Zurich-Montpellier school. This classification included also Qian's physiognomic units and also those described by Krestov. Considering the fact that there was no Japanese botanist as co--author of this chapter and considering the vast Japanese phytosociological literature, I do not know, how well this classification reflects actual Japanese conditions. Nevertheless, I can see it as a useful summary of the authors' knowledge of the Northeast Asia's forest vegetation.
I noticed the lack of a chapter on the Quaternary history of the flora and vegetation of Northeast Asia. I think this is a grave omission, since the recent vegetation picture depends very much on the past geological history of the area.
My last my complaint is the exorbitant price of the book. With its price being close to USD200.00, this book is well out of reach to for many vegetation students. The book is printed on the highest quality, heavy glossy paper, the phytosociological tables are difficult and expensive to produce and the high price can perhaps be justified. Nevertheless, it is a pity that this prohibitive price does will not make this book available to the a broader audience.
Dear readers of BEN,
Due to the large amount of spam that is sent to the BEN-L address, I ignore all the mail that is sent ether to BEN-L or to BEN-L-OWNER. If you want to contribute to BEN, please submit your articles, notes, reviews or announcements to my personal e-mail addresses: aceska@telus.net and aceska@victoria.tc.ca .
Many thanks,
Adolf Ceska