Conservation biology has attracted increasing attention in science, government and education. During the past ten years the public awareness of the present biodiversity crisis has shifted from a few flagship species towards general biodiversity. How far has lichenological research been influenced by this shift? In the recent "Encyclopedia of Ecology and Environmental Management" (Calow P., ed., Oxford, Blackwell, 1998), D. A. Falk gives a remarkable definition of conservation biology: "Conservation biology is an emerging, interdisciplinary field that seeks to establish a scientific basis for the conservation and management of populations, communities and ecosystems. At the same time, conservation biology draws on the empirical observations and results of land management practices as a primary source of information and insight. Consequently, conservation biology may be thought of as the interface between ecology and allied disciplines on one hand, and the practice of conservation management on the other". Almost every word of the above definition is a challenge to lichenologists because so little information on lichen ecology is available: In this discussion we would like to draw attention to gaps in our knowledge and especially, to stimulate further research in this discipline. - In earlier decades lichenologists developed a broad range of methodologies for environmental monitoring. Methods for assessing environmental health, from air pollution to forest continuity, made use of selected indicator species and indices based on presence or absence of these species. These methods were widely discussed and implemented, but the underlying concept of sensitive species is often disputed. In other areas of mainstream ecology there has been a move away from indicator species towards diversity, indices but lichenologists have only incompletely switched to these new concepts, often with the excuse that major groups were still incompletely known. Although this excuse is still valid in under-recorded areas of the world, the recent increase in excellent monographs of lichen groups that were formerly difficult to determine has altered this, so that assessing lichen diversity is now feasible at least in temperate and boreal zones of Eurasia and North America, and in Australasia for macrolichens. Can lichenologists now contribute to future biodiversity assessments? Only then will general conservation priorities be able to include lichens, the rustici pauperrimi (Linné).

Lichen hot spots and habitat protection: If we cannot identify all species in large areas of the world can we identify lichen hot spots? In Sweden all forest areas are required to have both environmental and productive goals since 1993. This has led to renewed interest in identifying key habitats in forest biotopes with high conservation values. Key habitats are defined by associated species in a number of groups including lichens, fungi and invertebrates, and are then targeted for further survey for Red Data Book species or others of high conservation priority. This approach also incorporates management objectives and practices, so will provide a basis for management decisions to protect the habitats of these species. Habitat protection for lichens has often consisted of a conserve (i.e. veteran trees) and do-nothing approach. But protection alone cannot permit long term conservation of target species. It does not account for the population dynamics of the target species, of the associated community or of environmental changes that may be occurring on smaller or larger scales in the protected area. Conservation of lichens urgently needs further study of both lichen habitats and lichen populations. Specific management practices associated with target species and communities also need to be conserved. This will require further development as well as communication to both the scientific community and to conservation managers.

Species conservation: Lichens have an advantage over many other organisms in that they frequently reproduce vegetatively, and successful rescue actions with thallus fragments and vegetative diaspores have shown that reintroduction and augmentation of lichen populations is practicable. However, these experiments have not been successful so far with crustose, umbilicate and fruticose species with a primary holdfast. Further research is needed to extend the methods to these growth forms.

Lichen ecology: Probably the greatest gap in our knowledge is in the population biology of conservation-dependent species. So far very little is known about "life table analyses" of lichens, although this information is required to specify the conservation status according to the present IUCN Red-List categories. Although it is not possible to undertake these studies for a wide range of taxa, a careful selection of key taxa representing a range of ecological strategies could contribute enormously to estimations of minimum viable population sizes for a great number of taxa and to an understanding of their life cycles. But many of us hesitate to start a project on life cycles on lichen thalli that may live to a great age, or where there may be a problem to identify a single individual. So how can we estimate age or survivorship? For the epiphytic species the measure of the tree age and the life table of the tree species can contribute to a reasonable estimation of the life table of the epiphytic lichen species. Recently, this type of study contributed to the estimation of a minimum viable population size of Lobaria pulmonaria in a mountain forest. Augmenting or reintroducing conservation-dependent populations could also profit from ecophysiological research. This discipline has already contributed to the understanding of the poikilohydric life style of lichens and attracted a wide interest of biologists. Direct contributions to conservation biology could include the definition and localisation of the ideal habitat for in-situ or ex-situ conservation programmes.

Lichen taxonomy: The taxonomic structure of lichen diversity as reflected in modern revisions includes a very low degree of endemism, and taxa previously reported from one part of the world are later found on another continent. Because national conservation bodies set priorities for endemic taxa, lichens do not usually receive high national awareness. One of the few examples where a lichen plays a key role in planning forest management is Erioderma pedicellatum. Since the species went extinct in Europe recently (Tønsberg, personal communication) Newfoundland now has international responsibility for this species and therefore is making reasonable efforts to protect Erioderma pedicellatum and its habitat. Many other species, are endangered in more than just one country but receive considerably less attention because of their wide geographical distribution. Does the present taxonomy really reflect the genetic structure of these species? This is a challenge for modern taxonomy where molecular methods are probably a powerful tool to detect a geographic pattern in an otherwise uniform taxon. If subspecies could be distinguished, such infraspecific taxa would merit a high conservation priority and more effective national conservation measures could be taken. Red Data Books: To make conservation management effective, lichenologists must document our present knowledge of the conservation status and of effective conservation measures to a broader public. Many national and regional Red Data Books are available; some of them merit a critical update regarding methods and sources of data used. National conservation authorities need modern Red Data Books based on recent floristical observations and taking into consideration the actual IUCN Red Data Book categories. However, the methodological problems related with national inventories for rare species should not be underestimated and a Red Data Book needs very careful planning and effective adaptation to related inventories in order to optimise the information gained from field surveys. On an international level a first step was the publication of a preliminary global red list of lichens compiled by G. Thor (http://www.dha.slu.se/guest/global3.htm). Erioderma pedicellatum is on this list, which helped enormously in convincing national bodies of the importance and conservation needs of this lichen species. However, we believe that more direct information about threats and conservation measures for lichens is needed. We propose that a "Status Survey and Conservation Action Plan" should be made for epiphytic lichenised fungi. The IUCN/Species Survival Commission Action plan series assesses the conservation status of species and their habitats, and specifies conservation priorities. The series is one of the world's most authoritative sources of species conservation information available to nature resource managers, conservationists and government officials around the world. A lot more work and international co-operation in lichen conservation biology will have to be done before a future edition of the Encyclopedia of Ecology and Environmental Management will eventually mention lichenised fungi somewhere on the 805 pages...

Thank you, Christoph and Pat for your comprehensive contribution. As you pointed out, lichen diversity assessments have recently been carried out in numerous countries or are in preparation. These - either as checklists, catalogues, or floras - are without doubts essential approaches towards a conservation biology of lichens. The preparation of Red Lists is a next step. Interestingly, Red Lists of different countries differ significantly by their included number of species. For example, the current Red List of Germany (Wirth, V. et al. 1996. Rote Liste der Flechten (Lichenes) der Bundesrepublik Deutschland Schr.-R. f. Vegetationskde. 28: 307-368) includes 1036 species, which is c. 61% of the total number of lichen species in Germany. A similar percentage will be presented in the forthcoming Austrian Red List (Hafellner, pers. comm.). On the other hand, much less of the lichen flora is included in the Red Lists of the British Isles (177 species= 11%) or Sweden (238 species= c. 12%) (Church J. M. et al., Red data books of Britain and Ireland: lichens. Volume 1: Britain. Joint Nature Conservation Committee, Petersborough., 1996, 84 pp. - Aronsson M. et al., Rödlistade växter i Sverige. ArtDatabanken. Uppsala, 1995, 272 pp.). What are the reasons for these differences? There are certainly several answers to this question (e.g. lichenicolous fungi included or not, not all species of the known flora analysed, differences in numbers of available habitats, and many more). However, to be scientifically sound, the consistent use of international standards in Red Lists, such as the IUCN categories, is demanded. Red Lists of lichens must become uniform at an international scale if they are intended as a serious tool in conservation management.

Conservation biology and lichens: Red Lists need to be consistent? Additional comments supporting Martin Grube's comment on Red Lists. - The consistency in Red Lists needs to be in the criteria for the listing which has two major considerations. One is rarity and the second is the "degree of threat to the species". So far most lichenologists have focused on the rarity issue. However, the magnitude (high or low) and the immediacy (imminent or non-imminent) of the threat is of greater importance! For example, a rare alpine lichen may have little threat to its habitat while a rare epiphytic lichen growing in a forested habitat may have an imminent high magnitude of threat. The threat in the forest may be due to commercial logging and natural forest fires, wind blow, or forest decline from air pollution. Some habitats are more threatened than others. Therefore, the degree of threat needs to be considered when setting criteria for a consistent system of rating.

I have been recently involved in lichen conservation, and found the task really challenging, especially because I could not use some of the criteria applied to other organisms; e. g. vascular plants. There is an obvious need to modify or (re-?) define these criteria, and to present the modifications to national conservation organizations. The results of conservation measures are often conditioned by the reproductive biology of the organisms. Unfortunately, no "seed bank" is available for lichens, and the reproduction by vegetative diaspores is absent in many lichen species. However, despite these and other shortcomings, I do agree that the subject needs an urgent attention, even if the results can only be regarded as preliminary. I would like to pose to this Forum the following questions for stimulating a little and well-due discussion on the subject: 1) When initiating lichen conservation in small regions, we are often required to evaluate the quantity and quality of the existing lichen populations, especially in fragile ecosystems, for establishing a preliminary Red List. In many cases it is very difficult to apply IUCN categories to these species, since we do not know if there has been a reduction in the population due to the lack of previous studies, besides the difficulty of counting individuals. 2) How do we apply IUCN categories when the total floristic knowledge of the area is below 50%? It would be desirable to obtain new data, but this can even aggravate the problem for rare species in endangered habitats. 3) How do we avoid including only the least collected and rare species? 4) Do you think it would be necessary to weigh or better evaluate an endangered habitat on the basis of its vascular plants, since the presence/absence of epiphytic communities often is a direct result of the impact on vascular vegetation? 5) Why do we not assume that a rare species is automatically also an endangered one? I believe there is a need to accommodate the IUCN categories to the above circumstances, and to establish new criteria to compile local Red Lists for lichens, similar to those developed for the "Preliminary Global Red List": the species included there often have little relevance at local level.

Additional comments on Violeta Atienza's contribution - 1, 2, 3) Lack of information is a major problem for lichen conservation. We must make decisions with the information available, and be prepared to change our decisions as new information is gathered. The form of reproduction is critical to evaluating a species potential for re-establishment in disturbed habitats. 4) The occupied and potential habitat and the individual species ecology needs to be evaluated when determining rarity and threats to a given taxon. 5) Rare species may not be endangered, but may just occur rarely due to their restricted habitat requirements. They are not endangered until their habitat is threatened or endangered by some action. Geographic scale was also discussed by Atienza, and is a major consideration when evaluating endangered species for a given area. One possible means to address this is to assign different rating at different geographic scales. For example, a common coastally influenced moisture preferring species, Pilophorus acicularis is not rare globally, and is given a global rank of G-5 (on a 1-5 scale) by the Natural Heritage Programs in North America. This ranking system was developed by The Nature Conservancy and is employed by the Natural Heritage programs in North America. But in the state of Idaho, USA, Pilophorus acicularis is only known from a single locality in northern Idaho, in an area known for its occurrence of coastal disjunct vascular plant species, and it is given a State rank of S-1 (on a 1-5 scale). This geographic scale provides an appropriate means of local and regional protection for significant species. One other factor which we as supporters of lichen conservation need to consider is that these lists become ineffective if they are not focused or understandable to the public. This means that the lists need to be realistic in: a) the number of taxa considered; b) they need to be simple if there are more than one category; c) and the Latin names may need to be grouped by guilds (e.g. forest epiphytes, forage lichens, nitrogen-fixing lichens, or ground steppe lichens), or d) by local vernacular names. For example ask yourself: is this red list reasonable to commercial logging companies and to the public? Or does the list include over half of the lichens that occur in the State and therefore, the logging company will ignore the list as unreasonable? Can the public understand what is on the list? Or are they just unfamiliar Latin names? Somehow the list needs to relate to the public (e.g. forage lichens, a term for the Alectoriod growth form lichens in trees which are eaten by wildlife, such as elk, deer, and flying squirrels; at least locally in North America where hunting deer and other animals is popular, the term "forage" is associated with food for animals, and therefore the public can understand that these are lichens eaten by animals and they support protecting them, since they support protecting animals!). Also I would suggest that lichens should be included, and their protection management be similar to vascular plants, since there is often an organized system established to address and protect vascular plant habitats.

Phytogeography of lichens (continuation of the Forum started in ILN 31, 1)

In our recent study (Goward & Ahti, J. Hattori Bot. Lab., 82, 1997), we have examined the western North American distributions of 84 taxa and chemotypes of Cladinae and Cladoniae occurring at temperate and boreal latitudes. We propose six broad conclusions, some of which may be of general interest to students of phytogeography: 1) Western North America's richest assemblage of Cladina and Cladonia, with between 76 and 78 taxa, occurs in British Columbia between 52°N and 56°N, in a region covered by glacial ice until roughly 13,000 to 10,000 years ago. 2) South of 52°N, species diversity declines dramatically, with a loss of between three and five taxa per degree of latitude. 3) With the exception of those species able to persist in nunataks at alpine elevations, or under arctic conditions to the north of the ice, or again in small, periglacial refugia along the west coast, most of British Columbia's Cladoniaceae must have passed the Pleistocene south of the Cordilleran Icesheet. 4) Floristic and chemical diversity in the Cladoniaceae are greater in humid than in arid regions, and at lower, forested elevations than at upper, alpine elevations. Many species can therefore be assumed to require habitats subject to only relatively brief periods of desiccation. 5) Given that many Cladoniaceae probably passed the Pleistocene south of the Cordilleran Icesheet, the absence of numerous species from all or most of Washington, Oregon, and California must reflect climatic changes in this region since deglaciation. An increase in summer moisture deficits is assumed to be largely responsible for this trend. 6) Though a majority of the Cladoniaceae are probably now at distributional equilibrium, a few species - e.g. Cladina stellaris and C. trassii - appear still to be extending their ranges southward from refugia north of the Cordilleran Icesheet.