Trevor’s Writings

Within the northern hemisphere a major proportion of the world’s rain forests at temperate latitudes occur along the west coast of North America. Fronting the Pacific Ocean, and centred in British Columbia at 43°N to 61°N, these coastal rainforests have long provided an international flashpoint for environmental concern. By contrast, their inland counterparts – the rain forests of intermontane British Columbia – are still poorly known, even to researchers. Located between 51°N and 54°N along the windward slopes of the Columbia and Rocky mountains, the inland rain forest phenomenon is unique to British Columbia. It is restricted to a region of anomalously humid climate, in which a plentiful snowmelt during late spring is followed by ample rainfall during the height of the growing season. More specifically, inland rain forests are confined to the wettest subzones of the Interior Cedar-Hemlock zone (i.e., the ICHwk and ICHvk); in no other region of the world has a similar integration of humidity and continentality been documented.

Nearly half of British Columbia’s rare tree-dwelling macrolichens have cyanobacterium as photobiont. Such species can be referred to as epiphytic cyanolichens. As a group, epiphytic cyanolichens have a requirement for nutrient- rich substrates with a pH above about 5.0; they tend to be absent from acidic substrates, including the bark of conifers. Viewed from this perspective, the copious presence of cyanolichens over the bark of pines, spruces, hemlocks, and other members of the Pinaceae in some portions of northwestern North America would seem anomalous. We propose that this phenomenon must reflect nutrient enrichment from sources extraneous to the trees themselves. Enrichment may derive, for example, from airborne dust, aerosols associated with the spray zones of waterfalls, or from nutrients present in the soil.

The importance of waterfalls and whitewater for lichen diversity is well known among field lichenologists but seldom has it been documented in the literature. We call attention here to a string of occurrences of eleven regionally rare lichens from waterfalls in inland British Columbia. Pseudocyphellaria mallota is reported as new to British Columbia and Haematomma ochroleucum new to Idaho. Psoroglaena stigonemoides is new to North America.

Lichen communities of forests often appear to be negatively affected by timber harvest presumably because of reduction of suitable substrate and increased desiccation. We examined species richness and composition of lichens on woods of logs of the same decay class in unlogged stands. (>140 years old) and logged, 20- to 30-year-old stands. There was no significant difference in species richness or mean lichen cover between logged or unlogged stands, but species composition differed, including species that were unique to either logged or unlogged stands. Crustose lichens accounted for 71% of rare species and all of the species occurring more commonly in unlogged stands; macrolichens accounted for 82% of common species and 60% of the species occurring more commonly in logged stands. Diameter at breast height and decay characteristics of down wood were the best predictors of lichen richness. Among lichen-rich, decay class 3 logs, relatively small amounts of retained down wood sustained lichen richness equivalent to unlogged stands. It appears important to ensure that decay classes favourable to lichens are retained after harvest.

On the windward slopes of the Columbia and Rocky Mountains is a disjunct rainforest that arguably includes the largest expanse of inland temperate and boreal rainforests on Earth. Although early biogeographers noted the unexpected presence here of numerous species typical of coastal regions, only recently have ecologists recognized these forests as a distinct entity: an inland counterpart to coastal rainforests of the Pacific Northwest.

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We now turn our attention to the status and condition of temperate and boreal rainforests as seen through the lens of conservation issues. We offer a comprehensive set of principles to help guide conservation groups and decision makers concerned about the fate of these rainforests.

The question has recently been raised whether Nephroma silvae-veteris Goward et Goffinet, an endemic species of the Pacific Northwest, might not appropriately be interpreted as the cyanomorph of L. oregana. This view is supported by comparison of fungal nucleotide sequences of the internal transcribed spacer and the 5.8S gene of the nuclear ribosomal DNA repeat from N. silvae-veteris with those of L. oregana. The fact, however, that N. silvae-veteris and L. oregana differ in several morphological and anatomical characters, as well as in the nature of their associated chlorobiont, suggests they are not entirely genetically identical. Nephroma silvae-veteris appears to be morphologically intermediate between L. oregana and N. arcticum, and may perhaps be interpreted as a species that arose through hybridization between L. oregana and N. arcticum. It is concluded that although N. silvae-veteris may appropriately be accommodated in Lobaria, it should for the time being be considered distinct from L. oregana. Consequently the combination L. silvae-veteris (Goward & Goffinet) Goward & Goffinet is made.

The new species Heterodermia sitchensis is described from British Columbia, Canada, where it is apparently a rare epiphyte restricted to sheltered localities at low elevations along the highly oceanic outer coast. Zeorin and atranorin are its primary phenolic constituents. Particularly interesting are the sterile, but sorediate, apothecial structures of this species. Heterodermia sitchensis is possibly a vicariad of the fertile H. podocarpa (Bél.) Awas.

The monotypic lichen genus Ahtiana Goward is here segregated from Parmelia s. str., and is demonstrated to have a close phylogenetic relationship with Cetraria s. lat. The type species, A. sphaerosporella, has a western North American distribution similar to that of its primary phorophyte, Pinus albicaulis Engelm.

The lichen genus Brodoa, comprising the so-called Hypogymnia intestiniformis group, is here segregated from Hypogymnia s. str. on the combined basis of a differing morphology, spore size, cortical structure, substrate, ecology and distribution. Phylogenetically, Hypogymnia s. str. appears to be more closely allied to Cavernularia and Menegazzia than to Brodoa.

The new species Hypogymnia oceanica is described from British Columbia, Canada, where it occurs as an epiphyte in humid localities, particularly along the outer coast. Physodic, physodalic, and protocetraric acids are its primary constituents. Hypogymnia oceanica is evidently a vicariad of the fertile H. occidentalis Pike & Hale. A key to the Hypogymniae of North America is provided.

The occurrence of 24 species of epiphytic macrolichens, many of which have previously been assumed to have strictly coastal distributions in western Northern America, is documented for five humid forests in inland British Columbia. These lichens were detected only in very old forests, and appear to be essentially absent from younger forest types in this region. Oldgrowth forests possibly favour such species by reason of their rather equable microclimate and relative environmental stability. The possibility is raised that some species may be relicts from the “Little Ice Age”, when climatic conditions were presumably more favourable to long-distance dispersal by lichens outside their current primary ranges. Not all oldgrowth forests are equally rich in oldgrowth-dependent lichens. Diversity appears to be positively correlated with forest age or, more precisely, with environmental continuity., In support of this, it is observed that successful long-distance dispersal by oldgrowth-dependent lichens occurs only rarely; older oldgrowth forests can therefore be expected to support a fuller complement of such species than younger oldgrowth forests. The possibility is raised that oldgrowth-dependent lichens may provide a rough index of environmental continuity in the oldest of British Columbia’s inland forests. The term “antique” is applied to such forests. It is concluded that old oldgrowth forests (= “antique forests”) are more valuable for the purposes of lichen conservation than young oldgrowth forests.

Based on field studies conducted in British Columbia in 145 forested sites of different ages, the distributional ecology of Nephroma occultum is described. Three macroclimatic “range classes” are recognized for this species: 1) a primary range, in which it is restricted to the upper and middle canopies of oldgrowth forests; 2) a secondary range, in which it colonizes the middle and lower canopies of oldgrowth and seral forests alike; and 3) a tertiary range in which it is confined to the lower canopy of oldgrowth forests. In British Columbia, N. occultum is judged to have its widest ecological amplitude in its secondary range, which may therefore be termed this species’ “effective ecological epicentre.”

Any viable conservation strategy intended to maintain N. occultum throughout its current distribution area must effectively treat this species as a separate ecological entity within each of its range classes. It is concluded that the range class model may prove useful for expressing the distributional ecologies – and hence the conservation requirements – of other oldgrowth-dependent lichens.

Nephroma occultum (Cryptic Paw Lichen) is a member of the Nephromataceae (Peltigeraceae) known to occur in Canada only in the humid, primarily oldgrowth forests of British Columbia. Twenty-one localities are recorded here for this western North American endemic, 18 of which were detected during field work for this report. Of the others, one is now known to have disappeared, owing to logging. Approximately 75% of the total known range of N. occultum occurs in Canada. The present study reports on about 150 thalli occurring within a total area of probably less than 100 ha. The total potential distribution of this species is, however, much greater than currently documented. Throughout most of its range, N. occultum is an obligate epiphyte restricted to oldgrowth forests. In Canada it is currently known to occur at elevations below about 1200 m within the Coastal Western Hemlock and Interior Cedar – Hemlock Zones. Its narrow ecology, especially within the latter zone, appears to reflect a strong requirement for high humidity and moderate summer temperatures. Only in the (climatically anomalous) Nass Basin does it regularly, though never abundantly, colonize younger forest types.

Although little information is available on a majority of British Columbia’s estimated 1800 lichens, previous studies of 350 foliose and squamulose species permit designation of 46 species as rare. Roughly 90% of these latter lichens occur in lowland biogeoclimatic zones in four of British Columbia’s 29 ecoregions, that is, Eastern Vancouver Island, Western Vancouver Island, the Thompson-Okanagan Plateau, and the Columbia Mountains and Highlands. These zones are therefore considered to be of critical importance for the maintenance of lichen diversity.

The distributional ecology of the tree-dwelling “hair lichens” Bryoria fremontii and B. pseudofuscescens is examined based on observations in high elevation conifer forests of inland British Columbia. Seven obvious microscale and mesoscale patterns are reported for one or both of these species: (1) a failure to successfully colonize branches occurring below the upper limit of the winter snowpack; (2) an occurrence in much lower abundance over the outer, foliated portions of branches than over the inner, defoliated portions of the same branches; (3) a tendency to periodic die-off in the outer, foliated branches, but not in the inner, defoliated branches; (4) a development of disproportionately heavier loadings over old, senescent trees than over young, vigorously growing trees of similar size; (5) an ability to colonize all levels of the forest canopy, including the upper crowns of trees; (6) an anomalously higher biomass in young stands growing in exposed sites than in young stands growing in sheltered sites; and (7) a development of considerable biomass in poorly illuminated stands that are nevertheless well ventilated. Based on these observations, the main distributional features of these species, and of Bryoria as a whole, are assumed to reflect a pronounced sensitivity to prolonged wetting, especially as a result of snowmelt. Other environmental factors are apparently less important, at least in the study area.

This paper presents 11 testable hypotheses pertaining to terrestrial lichens, forest dynamics, and woodland caribou on the Chilcotin Plateau of south-central British Columbia. Based on preliminary studies conducted in the lodgepole pine forests of the Very Dry, Cold subzone of the Sub-boreal Pine-Spruce biogeoclimatic zone (SBPSxc), it is suggested that caribou and terrestrial forage lichens are linked in a positive-feedback continuum dependent in the long term on periodic surface fire. The possibility is raised that fire suppression may adversely affect woodland caribou in this subzone. Further work is required.

British Columbia’s mountain caribou are behaviourally adapted to survival in regions of heavy snow. In winter when ground forage is buried out of reach, these animals subsist on a diet of tree-dwelling hair lichens. Caribou forage for hair lichens, especially Bryoria, in three contexts: 1) as litterfall; 2) in the crowns of recently windthrown trees; and 3) on the lower branches of standing trees. Litterfall and windthrown trees are especially important to caribou in their early winter habitats, often at lower elevations. The main winter range, however, is in the subalpine, and here they rely much more heavily on hair lichens growing on the branches of standing trees.

Bryoria biomass is heaviest in old-growth forests, where these lichens increase in abundance with increasing distance from the ground. Three vertical zones of abundance can be recognized:

• Zone A, in which Bryoria is virtually absent, is restricted to the basal portions of the canopy, its upper boundary (the “A/B threshold”) corresponding with the depth of the winter snowpack.

• Zone B is located directly above Zone A, and supports Bryoria at quite variable loadings, both spatially and temporally. The upward transition to Zone C is signalled by an abrupt increase in Bryoria abundance.

• Zone C is the zone of maximum Bryoria accumulation, especially on defoliated branches. Litterfall from Zone C contributes significantly to Bryoria biomass in Zone B, in part accounting for the highly variable Bryoria loadings characteristic of this zone.

Bryoria is unable to withstand prolonged burial by snow. Winters with exceptionally deep snowpacks cause upward shifts in the A/B threshold as buried Bryoria dies off. Thereafter, especially at subalpine elevations, the lower Bryoria trimline is likely to be situated well out of reach of caribou in early winter.

This can be predicted to delay the migration of caribou from their early winter habitat to their main winter range, because caribou are capable of foraging efficiently in subalpine forests only once deepening snows provide a feeding platform within about 1.5 – 2 m of the A/B threshold (or A/C in highly exposed sites).

Once elevated, an A/B threshold is slow to readjust downwards to its original position, requiring perhaps a decade or more. During this period, caribou can be predicted to spend more time than usual in their early-winter ranges, particularly in years when snowpacks are slow to build. Such years are probably highly stressful for caribou. Firstly, because these animals, effectively trapped at lower elevations, are at higher-than-average risk of encountering predators (owing to greater concentrations of other ungulates). Secondly, because as old-growth forests continue to be replaced by clearcuts, the likelihood of locating Bryoria-rich windthrown trees must also decline. Cratering for falsebox and other forbs of course provides some nourishment (less, however, in clearcuts than in forest settings), though the question needs to be raised whether the increasing lack of availability of hair lichens at lower elevations could result in food shortages for these animals.

The above Lichen-Snow-Caribou (LSC) hypothesis could provide a plausible explanation for the well-known tendency of caribou to perform annual vertical migrations much more pronounced in areas of heavy snows than in less snowy regions. It also suggests a framework against which to examine historic fluctuations in population size. In principle, caribou herds in areas of heavy snow ought to experience rapid episodic declines, followed by more gradual increases. Such declines, moreover, would be expected during the decade following a year of exceptionally deep snowpacks. Caribou populations in drier areas should be more stable.

To the extent that the LSC hypothesis is eventually validated, resource managers would do well to heed the warning implicit in it: low elevation old-growth forests may be crucial, at least in regions of heavy snow, to the long-term survival of mountain caribou. If so, then recent declines in the Revelstoke and Central Selkirk subpopulations could be simply an inevitable downward adjustment to existing conditions brought on by clearcut logging at the landscape scale.

Arboreal hair lichens belonging to the genus Bryoria provide crucial winter food for the threatened Mountain ecotype of the Woodland Caribou. Earlier studies suggest that the reliance of many Bryoria species on thallus fragmentation over a snow-covered subalpine meadow following a late winter windstorm of moderate force. Fragment densities were greatest immediately downwind of the forest edge, but remained substantial even at a distance of 2 km. This suggests that dispersal is not limiting for at least some Bryoria species at subalpine elevations. It is proposed that the ecological requirement of Bryoria fremontii and B. pseudofuscescens for well-ventilated habitats considerably enhances their ability to inoculate young, regenerating stands over considerable distances. Their observed general absence in young trees is probably a function of substrate limitations rather than of limitations of dispersal.

Three vertical zones of Bryoria abundance are recognized in the canopies of mid- and upper-elevation oldgrowth conifer forests in southern inland British Columbia. Zone A, with virtually no Bryoria, is restricted to the lower trunk and lowermost branches, where its upper boundary (the “A/B threshold”) corresponds roughly with the maximum settled depth of the winter snowpack. Zone B is located directly above Zone A, and supports Bryoria in variable amounts ranging from negligible to heavy; its upper boundary is defined by an abrupt increase in Bryoria at the “B/C threshold”. Above this is Zone C: a well ventilated region supporting maximum Bryoria loadings consisting predominantly of the nonsorediate species B. fremonti, B. pseudofuscescens, and Nodobryoria oregana. Bryoria loadings in Zone B benefit from litterfall from Zone C, in the absence of which, Zone B would predominantly support only the sorediate species B. fuscescens and B. glabra. Winters of exceptionally deep snow cause marked upward shifts in the A/B threshold, presumably resulting in reductions in the early-winter availability of Bryoria to Mountain Caribou. This is expected to prolong early-winter migrations to lower elevations, where Caribou depend on lichen-rich oldgrowth forests. The existence of such forests is hypothesized to be integral to the long-term maintenance of healthy Caribou populations.

The lichen Parmelia (subg. Parmelia) hygrophila Goward & Ahti, sp. nova, is reported from Alaska, British Columbia (typus), Idaho and Washington, where it is a widespread epiphyte in humid and subhumid sectors at low and middle elevations. Salazinic acid and atranorin are its major phenolic constituents. A key to the species of the P. saxatilis group in the Pacific Northwest is presented.

The distribution and general ecology of 293 macrolichen taxa are recorded for approximately 600 000 ha of mountainous terrain in Wells Gray Provincial Park and its vicinity in south-central British Columbia, Canada. Thirty-one taxa are documented for the first time from British Columbia, including seven from Canada, and five (Leptogium subtile, Usnea wasmuthii, and the lichenicolous fungi Corticifraga fuckelii, Echinothecium reticulatum, and Refractothilum peltigerae) from North America. 74% of the taxa included are essentially circumpolar, whereas only 11% are restricted to North America, in most cases western North America. A high proportion (71%) of the latter group is accounted for by corticoles. The Bioclimatic Zone System is used to indicate zonal distribution for the lichen species considered. Summaries of total ranges in the northern hemisphere are also provided. Duration of snow cover is considered to play a critical role in the distribution of many species, particularly terricoles. Numerous primarily coastal, oceanic lichen species are found to occur in the study area, including Cavernularia hultenii, Cladonia umbricola, Dendriscocaulon intricatulum, Hypogymnia enteromorpha, Parmelia pseudosulcata, Peltigera pacifica, Platismatia norvegica, Polychidium dendriscum, Pseudocyphellaria anomala, Sticta limbata, and Normandina pulchella.

Based on the western North American distributions of 71 taxa and chemotypes of Cladina and Cladonia occurring at temperate and boreal latitudes, the Coast Mountains of British Columbia are shown to form a major phytogeographic barrier, dividing 21 oceanic taxa to the west from 24 continental taxa to the east. Maximum floristic diversity in these genera occurs between 52°N, in a region occupied by glacial ice until roughly 10,000 years ago. Following deglaciation, many Cladoniaceae must have colonized this region from south of the Cordilleran Icesheet, presumably deriving from regions that no longer support them. South of 52°N, modern-day rates of decline average between three and five taxa per degree of latitude, and appear to be correlated with a southward trend from summer-moist climatic conditions to summer-dry. By contrast, the present southern limits of Cladina stellaris, Cladonia macroceras and C. stricta are believed to reflect historical, as opposed to strictly ecological, factors. Such species may still be extending their ranges southward.

Hypogymnia metaphysodes was first described from Japan and Sakhalin, and later reported from western North America. Here we show that the North American material currently referred to H. metaphysodes differs from that species not only morphologically and chemically, but also in ascospore size and shape. We also show that the North American material is in fact heterogeneous, and can be assigned to two well-defined species here described as new: Hypogymnia recurva sp. nov. and H. wilfiana sp. nov. Both of these lichens contain distinctive secondary metabolites: vittatolic acid in the case of H. recurva, and 2-methylene-3-carboxy-18-hydroxynonadecanoic acid (“apinnatic acid”), reported here for the first time from Hypogymnia, in H. wilfiana. Both of our new species are so far known only from western North America, where they occur primarily as epiphytes on the branches of conifers. Hypogymnia metaphysodes s. str. has not yet been reliably reported from this region and should be excluded from the North American lichen flora.

Qualitative and quantitative methods are used to determine an optimal sampling strategy for assessing and monitoring lichen abundance and distribution in different silvicultural treatments in high-elevation Engelmann spruce – supalpine fir forests near Sicamous, British Columbia. The resulting sampling methods are described in detail, and a list of 99 species reliably identifiable in the field is provided. Based on principal components and cluster analysis, we propose that lichen diversity in the study area may be monitored on the basis of nine substrate units.

In young forests of humid south-central British Columbia, Lobaria pulmonaria and other epiphytic “cyanolichens” attain optimum development over the lower branches of conifers growing within the dripzone of Populus. To account for this, we propose the existence of a “dripzone effect,” in which nutrient-rich leachates from the upper branches of Populus enhance the pH of nearby conifers to the benefit of cyanolichen colonization. The dripzone effect is presumably most pronounced in stands located over nutrient-rich soils, in which Populus plays a pivotal role in the early establishment of nitrogen-fixing epiphytic cyanolichens. This phenomenon is assumed to be widespread, but it apparently leads to colonization of conifers by cyanolichens only in humid regions not subject to acid rain. Through the presence of cyanolichens on trees belonging to the Pinaceae is probably indicative of allochthonous nutrient enrichment wherever it occurs, we stress that dripzone effect is only one of many mechanisms promoting the enrichment of conifer bark.

Based on a survey of 935 herbarium specimens collected from British Columbia, the substrate ecology and “lifezone” distribution of 48 species of epiphytic cyanolichens are broadly summarized. Conifers belonging to the Pinaceae provide habitat, in coastal regions, for at least 43 cyanolichen species, 12 of which occur exclusively on conifers. Hardwoods support a similar number of cyanolichens, but provide exclusive habitat for only four species. Cyanolichen diversity on conifer branches is shown to increase along a gradient of increasing summer precipitation.

It is suggested that the occurrence of cyanolichens on conifer branches (i.e. the “CC phenomenon”) was formerly well developed in many parts of Europe, but has declined in response to increasing acid precipitation. According to this hypothesis, existing epiphytic lichen assemblages in Europe no longer express their full pre-industrial ecological amplitude. In contrast, conifers in Pacific North America apparently still support “pristine” epiphytic communities; this region should be accorded special emphasis for global cyanolichen conservation. The CC phenomenon may offer a highly sensitive early warning system of broad-scale acidification in eastern North America and other regions where industrial activity is increasing.

Lichens in which a cyanobacterial partner occurs can be referred to as “cyanolichens.” Such species are potentially important contributors to the nitrogen budgets of some conifer forest ecosystems. In the intermontane forests of British Columbia, 31 epiphytic (tree-dwelling) cyanolichens are known to colonize conifers, including 12-species that can be considered rare or infrequent in the province as a whole. In this paper we present a simple key for predicting stand-level epiphytic cyanolichen diversity on conifers. The key is based on several readily mappable environmental factors and is useful at an operational scale. Maximum cyanolichen diversity is shown to occur in lowland old-growth rain forests established over nutrient-rich soils and subject to a rainfall pH above about 5.0. Such stands are generally restricted to the base of hill slopes in the wettest subzones of the Interior Cedar-Hemlock zone, where they not only support one of British Columbia’s richest assemblages of rare cyanolichens, but also themselves represent on of the province’s rarest and most endangered forest ecosystems. Further work is urgently needed.

The “dripzone effect” involves the above-ground transfer of nutrients – presumably in the form of leachates – from the upper crown of one tree species to the lower crown of another. In humid, poorly ventilated Picea stands, nutrient enrichment associated with Populus dripzones has been shown to promote the development of cyanolichens belonging to the Lobarion. Here we examine the same phenomenon in well-ventilated stands, in which members of the more xerophytic Xanthorion are favoured, while some species of the alectorioid lichen genus Bryoria are excluded. The latter phenomenon may partly account for the often discontinuous occurrence of Bryoria to many mixed conifer stands at lower elevations.

Sixty-five species of lichens and lichenicolous fungi are reported as new to British Columbia. Nineteen of these are documented from North America for the first time: Abrothallus cetrariae, Anzina carneonivea, Arthonia epimela, Brigantiaea purpurata, Buellia cristallifera, Caloplaca cerinelloides, C. oleicola, Carbonea aggregantula, Dermatocarpon linkolae, Fellhanera subtilis, Lecidella laureri, Leprolomma diffusum var. chrysodetoides, Plectocarpon nephromeum, Protothelenella leucothelia, Roselliniella nephromatis, Sclerophora amabilis, S. coniophaea, S. peronella and Verrucaria sphaerospora. An additional 18 species are new to Canada.

With a lichen flora expected to exceed 2,500 species, Canada supports one of the world’s richest lichen assemblages. Even so, comparatively little field work has been conducted to date on Canadian lichens. Indeed, many regions of the country have received little or no attention at all.

It is important to emphasize that Canada, by world standards, is a sparsely populated country, in which most natural ecosystems remain more or less intact. A majority of other industrialized nations, by contrast, have been much more profoundly affected by human activity, and have accordingly lost a considerable proportion of their original lichen floras. Denmark, for example, has already lost, or is on the point of losing, roughly 634 lichen species, or 70% of its original flora. Even Sweden, in which environmental conditions are more comparable to those in Canada, recently included 238 species (roughly 13% of the lichen flora) in its “Red Data Book of Plants”. From these observations, it may be inferred that at least some components of Canada’s lichen flora are likely to be in decline: a trend which can be expected to persist as Canada’s natural ecosystems continue to be lost to agriculture, urbanization, air pollution, and various forms of resource extraction.

Any serious attempt to develop a coherent conservation stategy on behalf of Canadian lichens must depend on: 1) an understanding of the scope and limits of past research; and 2) on-going assessments of those species judged to be at risk of extirpation. To date, no such efforts have been undertaken at a national level. The following report undertakes, in a prelimary way, to lay the foundations for a national effort to maintain Canada’s lichen flora at historic levels. The report thus consists of three parts: Section 1 provides a short history of lichen floristics in Canada; Section 2 is an annotated listing of lichen species thought to be at risk of extirpation; and Section 3 gives a prioritized summary of candidate species for which status reports are most urgently needed. Following the report is a bibliography in which most, if not all, of the most important publications pertaining to lichen floristics in Canada are listed.

In preparing our report, we have unfortunately been unable to give equal attention to all lichen groups. Crustose lichens in particular tend to be grossly underrepresented in most lichen collections, and cannot be reliably assessed at the present time, with the exception of a few more distinctive species. Crustose lichens, it should be mentioned, comprise more than two-thirds of Canada’s total lichen flora. The following report thus sadly neglects a group of lichens that, if adequately represented, would probably more than double its length. Instead, the report focusses primarily on macrolichens.

Listed here are 112 lichen species that may be considered to be at risk in Canada. This figure includes at least thirty species currently believed to be in serious decline, and another six that appear already to have become extirpated in this country: Alectoria fallacina, Heterodermia hypoleuca, Leptogium azureum, L. byssinum, L. dactylinum and L. rivulare. Perhaps not surprisingly, a majority of the lichens included here are restricted to southern regions – especially south coastal British Columbia, southern Ontario, and, to a lesser extent, New Brunswick and Nova Scotia – where the impact of human activity has been more pronounced than elsewhere. By contrast, lichen diversity in northern Canada appears to have been little affected by human activity, though a number of northern species have been included by reason of rarity.

To judge from the number of primarily corticolous species included in the list (47%), lichens of forest ecosystems appear to have been more adversely affected than lichens in other ecosystems. Some recent studies point to the special sensitivity of epiphytic lichens dependent on oldgrowth forests. Whether as a result of logging or, in central and eastern Canada, as a result of both logging and acid rain, many such species are apparently already in rapid decline. Meanwhile, elsewhere in the country, terrestrial lichens of various kinds are also in decline, as are aquatic and semi-aquatic lichens subject to industrial effluent. These comments again apply primarily to southern portions of the country.

The mountain caribou is a threatened ecotype of the woodland caribou restricted to east-central and southeast British Columbia as well as adjacent portions of Washington and Idaho. In winter these animals forage almost exclusively on arboreal hair lichens, especially Bryoria. Here we examine the vertical and horizontal occurrence of hair lichens within the canopy of a mid-successional, mid-elevational forest dominated by Engelmann spruce and subalpine fir. Our study yielded five key findings: 1) all hair lichen species potentially important to caribou are present 60 yr after stand initiation; 2) low-biomass sorediate species (mostly B. fuscescens) predominate in the lower and middle canopies; 3) high-biomass non-sorediate species (mostly B. fremontii and B. pseudofuscescens) are most abundant in the upper canopy; 4) hair lichen biomass is higher in open stands than in closed stands; and 5) hair lichen loadings are low when compared with earlier reports from old-growth stands. The last finding apparently reflects – in the upper canopy – a lack of defoliated branches and – in the middle and lower canopies – humid, poorly ventilated conditions. We suggest that a judicial use of stand thinning could considerably augment the production of non-sorediate Bryoria species in defoliated portions of the middle canopy. Within the lower canopy, however, thinning is unlikely to increase Bryoria loadings, except as a result of inoculation from the middle canopy.

Based on field studies and herbarium research, 46 species of lichens and lichenicolous fungi are reported new to British Columbia. The following 15 species are documented for Canada for the first time: Agonimia tristicula, Catapyrenium daedaleum, Cladonia luteoalba, Collema auriforme, Dactylospora lobariella, Fulgensia desertorum, Massalongia microphylliza, Pannaria ahlneri, Peltula euploca, Physcia callosa, Psora montana, Sticta wrightii, Usnea wirthii, Vestergrenopsis elaeina, and Xanthoparmelia planilobata. An additional nine species are new to North America north of Mexico: Acrosyphus sphaerosphoroides, Biatoropsis usnearum, Hawksworthiana peltigericola, Leptogium brebissonii, L. schraderi, Lichenochora thallina, Scutula miliaris, Sphaerellothecium araneosum, and Trapelia corticola.

The terricolous lichen Peltigera chionophila sp. nov. is described from the western cordillera of North America. It can be distinguished from other members of the P. aphthosa group by its even lobe margins, its uniformly corticate apothecial reverses, its well-defined veins that darken gradually toward the thallus centre, and by ts strict occurrence in mountainous regions subject to heavy, prolonged snow cover. Comparisons of sequences of the Internal Transcriber Spacer of the nuclear ribosomal DNA repeat support the taxonomic distinctness of this species. A map of its global distribution is provided.

Based on extensive field studies, herbarium research and thin layer chromatography, the taxonomy, distribution and ecology of 28 species of Peltigera occurring in British Columbia are discussed. Distribution maps are presented for selected species, and a key to the North American taxa is provided. Peltigera cinnamomea Goward is described as new, and the blue-green phototype of Peltigera leucophlebia (Nyl.) Gyelnik is documented for the first time. Peltigera scabrosella Holt.-Hartw. is reported as new for North America based on a collection from the Yukon Territory, Peltigera hymenina is new for British Columbia.

The epiphytic lichen Hypogymnia apinnata sp. nov. is described from the Pacific coast of North America. Although superficially similar to H. enteromorpha, H. apinnata is distinguished from that species both morphologically (in producing few or no marginal lobules) and chemically (in lacking medullary lichen substances). Range maps are provided for these common Pacific Northwest endemics.

Hypogymnia canadensis Goward & McCune is described as a new species of lichenized fungi from the west coast of North America, ranging from southeastern Alaska to western Oregon, inland to southeastern British Columbia. In many respects similar to H. metaphysodes (Asahina) Rass., H. canadensis is distinguished from that species by an imbricate growth form, more open branching, lobe tips that readily become brown in exposed sites, a darker ceiling of the lobe cavity, and the presence of 3-hydroxyphysodic acid in the medulla (K+ slowly reddish brown). So far H. canadensis is known from conifers in cool suboceanic to oceanic climates.

Until recently the lower Kispiox Valley supported extensive stands of antique, oldgrowth and/or late successional conifer forests. Though natural disturbances – fire, insect outbreak, windthrow – have presumably driven stand dynamics for thousands of years, the resulting forest mosaic has doubtless always incorporated old forests. Only very recently have oldgrowth forests essentially disappeared from the lower portions of the valley. In future, every effort should be made to ensure that cutting practices do not jeopardize the oldest remaining oldgrowth ecosystems which, according to our studies, support the richest macrolichen assemblages. Wholesale plantation forests will probably doom many epiphytic lichens in this critical portion of British Columbia.

The lichens (58 species), mosses (60 species) and hepatics (15 species) of Burns Bog are listed with special reference to their abundance and distribution within selected vascular plant communities. The modifying effects of vegetation structure and physiognomy on climate are considered to exert a major control over the observed distributional patterns of the cryptogams. Floristic diversity among the cryptogams is very high and has probably been enhanced by human activity in Burns Bog. At present, air pollution appears to affect lichen growth only at the bog margins. It is possible, however, that a further reduction in local air quality could significantly reduce cryptogamic diversity.

The coastal temperate rain forests of north-western North America are internationally renowned as the archetypal expression of the temperate rain forest biome. Less well documented is the existence of somewhat similar forests 500 – 700 km inland on the windward slopes of the Columbia and Rocky Mountains. Here we attempt to show that these inland ‘wetbelt’ forests warrant rain forest status. We report three key findings: (1) 40% of oceanic, epiphytic macrolichens found in Pacific coastal rain forests occur also in inland regions; (2) epiphytic species richness decreases with decreasing latitude, such that roughly 70% of disjunct oceanic species are restricted to regions north of 51° N; and (3) the southward decline in lichen diversity is correlated with a parallel decrease in summer precipitation, but not with mean annual precipitation. Main conclusions: These observations are consistent with the recognition of an inland rain forest formation between 50 and 54° N. Inland rain forests represent a small, biologically significant ecosystem whose continued fragmentation and conversion to tree plantations warrant close scrutiny.

Based on field studies, herbarium research, and previously overlooked reports, Hypogymnia pseudophysodes and Leptogium rivale are deleted from the British Columbia lichen checklist, while 27 species are either confirmed or reported as new. Clypeococcum hypocenomyceae, Hypocenomyce leucococca, Lecanora reagens, Phaeophyscia hirsuta, Physcia dimidiata, and Thelomma ocellatum are documented for Canada for the first time, and Abrothallus weiwitzschii, Arthonia vinosa, and Lecidea pullata are new to North America.

Twenty-three Usnea species and species groups are reported from British Columbia, Canada. Usnea chaetophora, U. diplotypus, and U. nidulans s. lat. are new to North America, whereas U. esperantiana and U. rigida s. lat. are documented for the first time for Canada, and U. ceratina and U. rubicunda are new to British Columbia. New chemotypes are also reported, e.g., in U. fragilescens var. mollis and U. subfloridana. Usnea stuppea (a synonym of U. substerilis) is lectotypified. A key to the genus Usnea in British Columbia is provided.

Two distinctive species of Leptogium (lichenized Ascomycotina, Collemataceae) are described. L. polycarpum P.M.Jørg. & Goward from humid coastal regions has 4-spored asci and bears copious small apothecia all over its upper surface. L. subaridum P.M.Jørg. & Goward from semi-arid intermontane regions of southern British Columbia and northern Washington is easily recognized by its shiny, thick, isidia and special ecology.

Mountain caribou (Rangifer tarandus caribou) in southeastern British Columbia subsist for most of the winter on arboreal hair lichen, mostly Bryoria sPages Foraging occurs mainly in old subalpine fir (Abies lasiocarpa) forests near treeline. Here, the lower limit of Bryoria in the canopy is dictated by snowpack depth because hair lichens die when buried in snow. Bryoria is often beyond the reach of caribou in early winter, prompting caribou to move downslope to where lichen occurs lower in the canopy and other foraging modes are possible. Snowpacks are normally deep enough by late winter that caribou can reach Bryoria where it is most abundant, at high elevations. Extending this to inter-annual comparisons, Bryoria should be less accessible during late winter of low-snow years following normal winters, or of normal to low-snow years after deep-snow winters. We hypothesized that when maximum snowpack in late winter is low relative to the deepest of the previous 5 years, mountain caribou will use lower elevations to facilitate foraging (“lichen-snow-caribou” or LSC hypothesis). We tested this with late-winter data from 13 subpopulations. In the dry climatic region generally and for minor snowfall differences in wet and very wet regions, caribou did not shift downslope or in fact were at higher elevations during relatively low-snow years, possibly reflecting the ease of locomotion. The LSC hypothesis was supported within wet and very wet regions when snowpacks were about 1 m or more lower than in recent years. Elevation declined by 300 m (median) to 600 m (25th percentile) for snowpack differences of at least 1.5 m. Greater use of lodgepole pine and western hemlock stands sometimes also occurred. Management strategies emphasizing subalpine fir stands near treeline should be re-examined to ensure protection of a broader range of winter habitats used by caribou under variable snowpack conditions.

The lodgepole pine (Pinus contorta) ecosystems of the west Chilcotin Plateau of British Columbia are important northern caribou habitat. This lichen diversity study is part of a larger research program in these forests, designed to develop and test silvicultural systems that maintain caribou winter range yet allow some level of timber harvesting. The research trial included the following treatments: unlogged control; group selection based on 30% area removal with stem-only harvesting; and irregular group shelter-wood based on 50% area removal via whole-tree harvesting. In 1995, prior to logging, the lichen assessment plots were established and measured. In 1998, they were remeasured, 2.5 years after logging. Results showed slight decreases in stand-level lichen richness (F = 4.51, P = 0.02), diversity (F = 3.65, P = 0.04), and abundance (F = 5.73, P = 0.01) in all the partial cutting treatments compared to the uncut controls. Differences between partial cutting treatments were not detected, possibly because of limitations in the study design. Correlation analyses found significant negative relationships between the amount harvest in each plot and richness (r = -0.34, P = 0.03), diversity (r = = -0.33, P = 0.0001) and abundance (r = -0.32, P = 0.05); and significant positive correlations between the amount harvested and percent cover of slash (r = 0.79, P = 0.0001) and direct beam solar radiation (r = 0.64, P = 0.0001).

Cladonia arbuscula (Wallr.) Flotow sensu lato is a widespread species complex traditionally divided among several subspecies on the basis of thallus morphology and secondary chemistry. Here we examine the evolutionary relationships of four of these segregates, C. arbuscula subsp. beringiana Ahti, C. arbuscula subsp. squarrosa (Wallr.) Burgaz, C. mitis Sandst., and an unnamed subspecies (referred to as C. arbuscula subsp. squarrosa PD – strain) in an attempt to link them to specific genotypes. The internal transcribed spacer regions of the nuclear ribosomal DNA (ITS rDNA) and the b-tubulin genes were sequenced for phylogenetic and haplotype analyses. In addition, the ITS2 RNA region was folded and changes were applied to the evolutionary hypothesis. We conclude that morphological differentiation within C. arbuscula s.l. is largely independent of variation in ITS rDNA and b-tubulin sequences, notwithstanding the distinct albeit incomplete clade formed by C. mitis. Compensatory base changes in the ITS2 RNA secondary structure could not support reproductive isolation. It is recommended that C. mitis be recognized at the subspecific rank as C. arbuscula subsp. mitis, and that subsp. squarrosa be included in subsp. beringiana. The apparent lack of correlation in C. arbuscula between genetic variability in the mycobiont and observed morphological variation in the thallus is intriguing, and requires explanation.

Nephroma occultum is a COSEWIC listed cyanolichen of “Special Concern”. It is endemic to old-growth cedar-hemlock forests in western North America. This is the first study to place N. occultum into a phylogenetic framework using nucleotide sequence and secondary structure data. It also addresses the phylogenetic relationship between N. occultum and N. arcticum. Analysis of fungal Internal Transcribed Spacer (ITS) ribosomal DNA (rDNA) produced four major clades. The cyanobacterial transfer RNALeu intron (tRNALeu) from N. occultum was separated from that of N. isidiosum and fell between the Eurasian and North American epiphytic taxa. Examination of length and complexity of the folded secondary structures revealed different trends in the ITS1 and ITS2 rRNA regions. Even though N. occultum is endemic to North America, it seems more closely related to South American temperate rainforest species than to the sympatric N. arcticum. Nephroma occultum is alone among the studied species of Peltigerales in having an exceptionally long ITS1 region, and a different tRNALeu intron DNA sequence of the photobiont suggesting association with a unique genotype of Nostoc. It may be argued that the fitness of N. occultum may be influenced by the complex ITS1 RNA structure, a unique photobiont genotype undergoing a genetic bottleneck, no sexual reproduction to generate variation, and the inability to associate with different photobionts to adapt to changing habitats.

Recent methodological developments in the preparation of Red Lists and status surveys have strengthened the reliability of both these approaches to at-risk designation. Ongoing efforts to harmonise the use of at-risk categories will provide a basis for even greater consistency between them. Notwithstanding these positive trends, however, there is not too much reason for optimism regarding the future of lichen conservation. While the power of Red Lists and status surveys to assist in conservation management has increased, their level of acceptance by politicians and conservation authorities continues to lag behind. The practical utility of these tools appears to depend less on their scientific merit than on the cost-effectiveness of the recovery plans that flow from them. What is more, in the harsh bureaucratic reality of conservation practice, the aesthetics of the target organisms are often at least as important as their ecological significance. Unfortunately, lichens are seldom accorded a high ranking for conservation: a state of affairs certainly in the part related to their small size, general inconspicuousness, and lack of big brown eyes. Even lichens that have been well documented as critically endangered often fail to receive an adequate level of conservation priority. This unsatisfactory situation is likely to change only when lichens have acquired a higher public profile. Clearly, these organisms have yet to achieve their full potential political import. We urge our colleagues to join us in sharing – with politicians, conservation authorities, the media, and the broader public – our collective sense of the importance of lichens, not only as biological chinking and surpassing modes of symbiosis, but also as monitors of ecosystem functioning.

Data entry on a computer is a mechanical process. Once the data have been entered, they can readily be sorted, and the resulting data set can be issued in the form of a book. Of course the ultimate value of such a book resides in the accuracy and completeness of the data on which it is based. In the present instance, accuracy and completeness would in turn require a profound knowledge of the organisms and the pertinent literature concerning them. This, unfortunately, the book’s authors do not possess.

Pseudocyphellaria rainierensis is an epiphytic cyanolichen endemic to humid forests extending from southeastern Alaska to Oregon in the Pacific Northwest of North America. It is extremely rare in both British Columbia and southeastern Alaska, where it is restricted to the understory and lower canopy of coastal old-growth forests. In Oregon and Washington, P. rainierensis occurs sporadically in mature forests as young as 140 years, but it can be abundant in humid old-growth forest canopies as long as branches are not overwhelmingly dominated by bryophytes. Its patchy distribution within forest stands may be attributed to dispersal limitations or, in some forests, to localized nutrient enrichment in the drip zone of certain tree species (e.g. Chamaecyparis nootkatensis). In the Oregon Cascades, transplant experiments demonstrated that a broad range of forest age classes provide suitable habitat for P. rainierensis. Its absence from young forests could therefore be attributed to slow rates of dispersal and/or environmental instability associated with rapid canopy height growth. Edge effects are a potential threat to old-growth associated lichens, but P. rainierensis can acclimate to some forest edge environments and even flourish on large trees adjacent to clearings. Since logging has eliminated most P. rainierensis populations globally, short-term conservation of this species must rely on the establishment of old-growth forest reserves. Silvicultural procedures such as reduced size of cutting units, live tree retention, maintenance of understory Taxus and deciduous trees, uneven thinnings, and extended rotation ages have potential to promote P. rainierensis in managed forests in at least some portions of its range.

Recent surveys of the inland rain forests of British Columbia and adjacent regions have brought to light an unexpectedly rich epiphytic lichen flora, including several species apparently new to science. In the first of a series of papers, we describe eight species discovered during these surveys as new: Absconditella amabilis T. Sprib. (Ostropales), Bacidina contecta S. Ekman & T. Sprib., Biatora aureolepra T. Sprib. & Tønsberg, Biatora ligni-mollis T. Sprib. & Printzen (all Lecanorales), Collema coniophilum Goward (Peltigerales), Pertusaria diluta C. Björk, G. Thor & T. Wheeler (Pertusariales), Schaereria brunnea C. Björk, T. Sprib. & T. Wheeler (Ostropomycetidae incertae sedis) and Scoliciosporum abietinum T. Sprib. (Lecanorales). We also call attention to a ninth species, Bacidina sp. A, a poorly known and possibly undescribed colonizer of moribund cyanolichens. A majority of the above species appear to be confined to old-growth forests, while two (Biatora ligni-mollis and Schaereria brunnea) are currently known only from “antique” forests older than about 500 years. Many additional undescribed epiphytic lichens are known from inland rain forests, underscoring the need for further baseline biodiversity research in light of its ongoing disappearance as a result of resource extraction. In addition to the eight new species, we report Absconditella celata as new to North America, Absconditella lignicola as new to Canada and Montana, Bacidina chloroticula as new to British Columbia and Gyalideopsis piceicola as new to Montana.

Dead wood is an important habitat feature for lichens in forest ecosystems, but little is known about how many and which lichens are dependent on dead wood. We reviewed substrate use by epiphytic lichens in the combined floras of Fennoscandia and the Pacific Northwest of North America based on literature and herbarium data and analyzed substrate affinity relative to life form, reproductive mode and major phylogenetic group within the floras. A total of 550 (43%) of the 1271 epiphytic species in the combined floras use wood, and 132 species (10%) are obligately associated with dead wood in one or both regions. Obligate and facultative wood-dwelling guilds in the two floras were strongly similar in terms of internal guild structure in each region, but differ somewhat in species composition, while the bark-dwelling guild differs strongly in both. Most obligate dead wood users are sexually reproducing crustose lichens. The largest numbers of species are associated with forest structural features such as logs and snags that have been greatly reduced by forest practices. Conservation of lichens inhabiting wood requires greater attention to crustose lichen species and the development of conservation strategies that look beyond numbers and volumes of dead wood and consider biologically meaningful dead wood structure types.

The Acharian “form genus” Cetraria is a large heterogeneous assemblage of predominantly foliose lichens, most of which can be characterized morphologically by the presence of marginal apothecia and chemically by the production of various fatty acids. Beginning in the late 1960’s (Culberson & Culberson 1965, 1968), but especially since the late 1980’s (Awasthi 1987: Kärnefelt et al. 1992, 1993; Kärnefelt & Thell 1993; Mattsson & Lai 1993; Thell 1995a; Thell et al. 1995a,b), Cetraria sensu lato has been subject to intense taxonomic scrutiny. As a result of this activity, the species formerly united within it are now placed in approximately 20 segregate genera. The present study describes a new segregate genus, Kaernefeltia, to accommodate two western North American species hitherto known as Cetraria californica (Cornicularia californica) and Cetraria merrillii (Tuckermannopsis merrillii).

The formerly monotypic genus Ahtiana (type species: A. sphaerosporella (Müll. Arg.) Goward is shown to include two additional species. A. aurescens (Tuck.) Thell & Randl. and A. pallidula (Riddle) Goward & Thell. All three species are endemic to North America, and are characterized by their greenish yellow, upper surface, globose ascospores, and caperatic acid in the medulla. The habitat ecology of these lichens is very specialized. Ahtiana is presumably most closely related to Tuckneraria Randl. & Thell and other cetrarioid genera having globose ascospores.

Cladonia norvegica Tønsb. & Holien was first described by Tønsberg & Holien (1984) from Norway. Since then, however, this species has proved to be widely distributed, having now been reported from Sweden, Finland, West Germany, Austria, Czechoslovakia, Italy, Madeira and southern South America (Argentina and Chile) (Muhr 1987, Ruoss et al. 1987, Wirth 1987, Kuusinen et al. 1989, Timdal 1989, Stenroos & Ahti 1990). The purpose of this note is to document the further occurrence of C. norvegica in North America.

Three lichen species forming both a foliose chlorotype and a dendriscocauloid cyanotype are documented from western North America. Lobaria amplissima is reported from northern California and southeastern Alaska and is new to North America. Sticta oroborealis Goward & Tønsberg, sp. nov. is described from a small area in north coastal British Columbia. The cyanotype of Sticta wrightii, hitherto unknown, is reported from coastal southeastern Alaska. The cyanotype of all these species occur primarily as epiphytes in old-growth forests supporting a high cyanolichen diversity. The occurrence of ”Dendriscocaulon” intricatulum (Nyl.) Henssen in Pacific North America is questioned.

Bryoria fremontii and B. tortuosa are the only species in the lichenized ascomycete genus Bryoria known to contain the pulvinic acid derivative vulpinic acid. In B. fremontii this yellow pigment is restricted to the soralia and apothecia, while in B. tortuosa it can occur throughout the thallus. The actual amount of vulpinic acid produced by B. tortuosa isd rather variable, however with intermediate specimens bearing both white and yellow pseudocyphellae. We studied the relationship between the two species with parsimony analysis using four DNA regions: 1) the internal transcribed spacers of the nuclear rDNA including the 5.8S region (ITS), 2) partial sequences from the intergenic spacer of the nuclear rDNA (IGS), 3) partial sequences from the small subunit of the mitochondrial rDNA (mtSSU), and 4) partial sequences from the protein-coding glyceraldehyde-3-phosphate dehydrogenase gene (GAPDH). Our phylogenetic analysis revealed that B. fremontii and B. tortuosa must be regarded as conspecific, but allowing for some genetic differentiation between European and North American populations. Bryoria tortuosa is therefore synonymized with B. fremontii.