UNPUBLISHED MANUSCRIPT Prepared for the B.C. Forest Science Program Project Y NOT ALL OLD-GROWTH IS EQUAL: ECOLOGICAL ATTRIBUTES AND LICHEN

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1 NOT ALL OLD-GROWTH IS EQUAL: ECOLOGICAL ATTRIBUTES AND LICHEN BIODIVERSITY IN AN INLAND TEMPERATE RAINFOREST LANDSCAPE By David N. Radies., Darwyn S. Coxson., Chris J. Johnson., and Ksenia Konwicki. 0. Ecosystem Science and Management Program University of Northern British Columbia Prince George, B.C. Canada, VN Z contact: darwyn@unbc.ca. Timberline Natural Resources Group th Ave. Prince George, BC VL R Running Title: NOT ALL OLD-GROWTH IS EQUAL 0 Key Words: inland temperate rainforest; canopy lichens; cyanolichens; indicators; relative soil moisture; old-growth; Thuja plicata; ecosystem-based management; old- growth threshold targets; ecological representation.

2 0 0 Abstract. Windward slopes of the inland mountain ranges in British Columbia support a unique temperate rainforest ecosystem. Continued fragmentation and loss of old-growth forests in this globally rare ecosystem, has led to calls for the identification of conservation priorities between remaining stands. We address this question by surveying the relative abundances of canopy macrolichens over a 0-km area of remaining oldgrowth (>0 years) forest in the upper Fraser River watershed, British Columbia, Canada. To ensure adequate representation of landscape-scale old-growth forest characteristics, we divided study plots equally among leading tree species and between broadly defined sites of wet and dry relative soil moisture. Other variables included: minimum mean annual temperature, mean annual precipitation, solar loading, and canopy openness. We used two statistical techniques: Nonmetric Multidimentional Scaling ordination for analysis of lichen assemblages and logistic regression to evaluate the habitat conditions of a subset of lichen species previously identified as old-growth associated. Ordination suggested that community assemblages were greatly influenced by both the presence and abundance of bipartite cyanolichens. These communities correlated well with increasing levels of relative soil moisture, temperature, precipitation, and canopy openness, with little to no significant effect of tree leading species. Logistic regression models identified relative soil moisture and temperature in all parsimonious models. Leading tree species, in combination with moisture and temperature, were important factors explaining the presence or absence of of modeled lichen species. Our results emphasize the importance of maintaining representative areas of oldgrowth forests that are potentially less prone to natural disturbances such as fire. Of

3 concern to the maintenance of lichen populations in old-growth inland temperate rainforests is the continued forest harvesting of low-elevation water-receiving sites. We recommend conservation of these wet topographic positioned areas to meet provincially set ecosystem-based old-growth threshold targets for the purpose of maintaining biological diversity and ecological integrity.

4 0 0 INTRODUCTION Wet-temperate rainforest ecosystems are widely recognized as an important repository of biodiversity, particularly for organisms that live within the forest canopy (Kitching et al., McCune et al. 000, Castellón and Sieving 00). In British Columbia (B.C.), important steps have been taken for conserving large regions of coastal temperate rainforests (Coast Information Team 00). However, a second major wettemperate rainforest ecosystem is found on the windward slopes of interior mountain ranges. This inland temperate rainforest (ITR) has many unique characteristics, including globally significant assemblages of canopy lichens (Goward, Arsenault and Goward 000, Goward and Spribille 00), serving as habitat for endangered populations of mountain caribou (Stevenson et al. 00), and supporting headwater spawning runs for many of the Fraser River salmon populations (Kew ). A major difference between coastal and inland temperate rainforest ecosystems in B.C. is that ITR ecosystems receive approximately half the annual precipitation of the former. Therefore, the development of rainforest attributes in the ITR is more dependent on patterns of snowmelt that influence ground moisture conditions. Eng (000) noted that stands located on cool north facing slopes showed a near 0-fold reduction in stand destroying fire frequency compared to stands associated with warm south facing aspects in inland mountainous forests of central B.C. Beaty and Taylor (00) reiterated this influence of aspect and further identified a reduced fire frequency in lower slope, water-receiving topographic positions. DeLong () reported that fire return intervals in wet montane forests of the upper Fraser River watershed ranged from to over 00 years while Sanborn et al. (00) found a median time since fire in wet

5 0 0 inland temperate rainforests between years. These results suggest that disturbance processes in the wettest portions of ITR are more similar to coastal temperate rainforests, where single-tree gap dynamics dominate due to tree age (Lertzman et al. 00), while in drier parts of the ITR, stand replacing fires will occur, yet infrequently. In the upper Fraser River watershed, this resistance to fire in wet toe-slope valley bottom positions has favored the development of forest stands that contain western red cedar (Thuja plicata) trees of exceptional age (i.e., 000 years old) and stature (i.e., meters in diameter) (Benson and Coxson 00). Goward and Arsenault (000) identify these forest stands as antique : sites where the last major disturbance event, such as fire, happened well before the current generation of trees established. Preliminary studies (Goward 00) in the upper Fraser River watershed have suggested that forest stands in water-receiving toe-slope positions contain highly diverse communities of arboreal lichens. Human impacts on ITR watersheds of the upper Fraser River valley have occurred mostly in valley-bottom locations. Extensive forest harvesting (and accidental fires) accompanied railroad development along the upper Fraser River valley in the early 00s, followed by highway development on north facing slopes in the mid 0s. Thus, while DeLong (00) identified a natural range of variability between -% in the cover of old-growth forests in wet mountain trench ecosystems of the upper Fraser River watershed, current cover estimates of approximately -% (Anonymous 00) suggest that these old forest types are under-represented relative to nonanthropogenic disturbance regimes. These trends parallel those in coastal wet temperate rainforests, where historical

6 0 0 harvesting has similarly targeted old-growth forests in valley bottom locations (Moola et al. 00) Current landscape level management policies in the upper Fraser River watershed specify an ecosystem-based management threshold of no less than % old-forest cover greater than 0 years of age (Anonymous 00). This target, influenced by both ecological and socio-economic considerations, does not necessarily ensure that old-forest stands of high biological value will be retained in future landscapes. Indeed, the opposite may be true, in that the placement of transportation corridors through toe-slope stands in the upper Fraser River watershed has resulted in disproportionate clear-cut harvesting of old-forest stands in surrounding valley bottom positions. In the U.S. Pacific Northwest and elsewhere canopy macrolichens have been used as indicators of stand age (Hyvärinen et al., Campbell and Fredeen 00) and environmental conditions on forested landscapes (McCune et.al. 000, 00, Lidén and Hilmo 00). Furthermore, macrolichens have proven to be useful indicators of total lichen diversity (Bergamini et al. 00) and other taxa (Negi and Gadgil 00) when applied appropriately (sensu Niemi and McDonald 00). Therefore, we suggest that a landscape-level assessment of canopy macrolichens in ITR, could provide major advances in our understanding of the role old-growth site and stand structural attributes contribute to the biological integrity of these ecosystems. We addressed this hypothesis by evaluating the composition and abundance of canopy macrolichens in relation to structural and site attributes in old-forest stands, located within a 0-km area of the upper Fraser River watershed. Landscape-level sampling was stratified to ensure equal representation of wet and dry broad relative soil

7 0 0 moisture (BRSM) site conditions. Reasons for stratifying our study design by soil moisture are twofold. First, soil moisture affects the ecology of forested landscapes including the development and structure of forest stands (Lertzman 00, Spies et al. 00), plant species numbers (Zinko et al 00), and underlying ecological processes (Pastor and Post, Turner ). Second, relative soil moisture is a forest management tool, applied from site-specific forest practices (DeLong et al. 00) to coarse-filter landscape-level planning implementation using G.I.S. technology (Anonymous, Iverson et al. 000). Furthermore, we stratified each of the two BRSM categories into an equal number of cedar- (Thuja plicata), hemlock- (Tsuga heterophylla), and spruce- (Picea glauca x P. engelmannii) leading stands, identifying the potential influence of substrate on lichen diversity (Goward and Arsenault 00). Our analysis uses ordination approaches to examine community level responses of canopy lichens, and logistic regression to examine autecological responses of a subset of individual species identified by Goward () as old-growth associated. We hypothesized that lichen communities respond as ecological guilds or functional groups (sensu Walker ) to environmental gradients within old-forest stands. Following our null hypothesis, responses to environmental gradients will be species-specific. Our research provides guidance on the interpretation of canopy macrolichens as indicators of both microclimatic conditions and forest stand continuity in old-growth inland temperate rainforests. We also address gaps in ecosystem-based management strategies on the importance of site and stand-level old-growth representation (Anonymous 00, Coast Information Team 00, Price et al. 00).

8 0 0 The ecology, conservation status, and range and magnitude of threats of lichens are not well understood (Fazey et. al 00). This study represents the first landscapelevel analysis of arboreal lichen habitat attributes in old-forest stands of the inland temperate rainforest of western North America. There is a pressing need for this type of study, given the rapid conversion of representative valley bottom temperate rainforests to plantation management and the attendant loss of old-growth associated species. METHODS Study Area The study area is located in east-central B.C., Canada, in the upper Fraser River watershed (Fig., Insert ). This region is part of the inland temperate rainforest or interior wet-belt (Stevenson et al. 00) of the Rocky and Columbia mountains that consists of: high elevation wet and very wet Engelmann Spruce Sub-alpine Fir (ESSF) forests (in blue) (between º - º latitude); mid to low mountain elevation, wet and very wet Interior Cedar-Hemlock (ICH) forests (in green) (between º and º latitude); and extreme valley bottom locations of the very wet-cool Sub Boreal Spruce (SBSvk) forests (in yellow) (between º and º latitude). We focused on forests in the Slim variant of the very wet-cool ICH biogeoclimatic subzone (ICHvk) (DeLong 00), and to a limited extent, adjacent valley bottom forests within the SBSvk (Figure ). ICHvk forests are dominated by western redcedar (Thuja plicata), hereafter referred to as cedar and western hemlock (Tsuga heterophylla), hereafter referred to as hemlock, with some Douglas-fir (Pseudotsuga menziesii), hybrid white spruce (Picea engelmanni x P. glauca), hereafter

9 0 0 referred to as spruce, and sub-alpine fir (Abies lasiocarpa), hereafter referred to as fir. SBSvk forests are dominated by spruce and fir. The distribution of remaining areas of old-forest in the ICHvk and SBSvk varies greatly across the upper Fraser River watershed (Fig. ). Many of the tributary valleys have been heavily logged and have little remaining old-forest cover. Furthermore, based on location of most logging clear-cuts, it is evident that harvesting patterns have targeted low elevation wet broad relative soil moisture (BRSM) sites, most notably spruce and secondly cedar. In general, wet BRSM sites are primarily found on north-facing slopes in mid to lower valley positions, though they occupy a more topographically restricted band in toe-slope positions on south facing slopes (i.e., compare Insert and Insert Driscoll Ridge, Fig. ). Wet hemlock-leading sites are more spatially confined, often occurring in lower valley topographically flat positions with standing surface water. Spruce-leading forests, both wet and dry, are found across upslope topographically cold locations (ESSF) and extreme low elevation sites (SBS), in part, due to cold air pooling. Mean annual precipitation of the ICHvk is. mm (. mm in summer and. mm in winter) with a mean summer temperature of. C and a mean winter temperature of. C. Recorded mean annual snowfall is 0. mm persisting on the ground for up to months of the year (Reynolds ). Slow-melting snow packs in higher mountain elevations tends to keep soil moisture levels high in the ICH during the summer months (Ketcheson et al. ), particularly on north-facing aspects. Study Design Field data were collected in summer 00 and 00. We selected GIS polygons to sample from a total of 0 randomly selected candidate polygons (Fig. ).

10 0 0 Selection criteria for eligible polygons (hereafter called stands) included: a) location in the ICHvk and in the adjacent SBSvk (within km of the ICHvk) biogeoclimatic subzones; b) forest greater than 0 years in age; c) cedar, hemlock, or spruce leading; d) 00 m or less from road access (for logistical purposes) and; e) at least 0 m from cutblock edges, riparian areas, and deciduous forest types. We used the B.C. Ministry of the Environment Predictive Ecosystem Mapping (PEM) database (an ecosystem mapping conducted at a :0,000 scale; see Anonymous ()) and the B.C. Ministry of Forests Vegetation Resources Inventory (VRI) database (a forest inventory mapping; see Anonymous ()) to identify candidate polygons that met our selection criteria. Sampling within old growth forests was stratified to ensure representation from each of cedar-, hemlock-, and spruce-leading stands (using VRI), and from stands representing both wet or dry BRSM conditions (using PEM). At each stand, we laid out plots that shared a common centre. The lichen assessment plot was a rectangular survey area 0m x 00m, with the long axis parallel with the slope to avoid marked topographic changes. Each plot was assessed for possible arboreal foliose lichens (checklist adapted from Goward et al. ) using survey methods of McCune et al. (000). Each macrolichen species observed was given an abundance rating between 0 and (with the exception of Lobaria pulmonaria): 0 = absent, = rare [- individuals/plot], = uncommon [-0 individuals/plot], = common [>0 individuals], = very abundant [covering more than half of available substrates]. For L. pulmonaria, similar categorical measurements were made, yet because of its ubiquity and high abundances in this ecosystem, we used a measure of hand-size (approximately 0 x 0 0

11 0 0 cm )/lichen plot in place of individuals/lichen plot. Melanelia and Parmelia lichens were surveyed at the genus level. The stand structure plot was a circular plot with a radius of. m. The purpose of the stand structure plot was to provide more detailed information on the structural components of the forest stand structure and RSM conditions. Diameter at breast height (DBH) (. m) was measured for all stems greater than. cm DBH, categorized by live and dead stems and identified by tree species. Relative Soil Moisture (RSM) of each stand was classified on a seven point scale using the moisture regime key in DeLong (00), which incorporates measurements of slope, mesoslope, aspect and soil texture. Soil samples for texture analysis were obtained from within a soil pit dug to approximately one meter at plot centre. At each of locations in each lichen assessment plot (equally spaced on lines radiating from plot center) four replicate measurements of canopy openness were taken using a spherical densiometer. These measurements at each location were taken at 0 intervals, and then averaged. We subsequently pooled all averages to obtain the overall openness of the stand. Predicted mean annual precipitation and temperature for each stand was obtained from the Canadian Forest Service (CFS) regional climate database (Hutchinson ). We used mean monthly minimum temperature for the months March-October in our analysis; this reflected the seasonal time period during which most lichen growth occurs (Coxson and Stevenson 00). Potential solar insolation was calculated using SAGA- GIS Version.0 (Scilands GmbH, Göttingen, Germany) solar radiation model.

12 0 0 Data Analysis Nonmetric multidimensional scaling (NMS) ordination was used to examine trends in lichen community composition across stands (PC-ORD V..0, McCune and Mefford ). We then used a general linear regression model to evaluate the following variables against ordination scores for Axes and : temperature (TEMP), precipitation (PRECIP), solar insolation (SOLAR), canopy openness (OPEN), relative soil moisture (RSM), and basal area of cedar (BACw), hemlock (BAHw), spruce (BASx), and subalpine fir (BASf). Variables were tested for multicollinearity (Stata Corporation 00, College Station, Texas). For all variables, we used a tolerance score of < 0. to indicate significant multicollinearity (Menard 00). We used logistic regression to identify important environmental factors that influenced the distribution of lichens observed in our sample plots. We fit logistic regression models to presence-absence data for Cavernularia hultenii, Lobaria retigera, Nephroma isidiosum, Nephroma occultum, Platismatia norvegica, Peltigera collina, Sticta fuliginosa and Sticta oroborealis, species previously identified as old-growth associated by Goward (). Independent variables we assessed for each lichen species included: categorized broad RSM (BRSM categorized as wet or dry see below) canopy openness (OPEN), average minimum temperature (TEMP), average annual precipitation (PRECIP), solar insolation (SOLAR), and categorized leading tree species (LEAD, categorized as Cw, Hw, or Sx, see below) Plots were classified as wet when the BRSM was above on the point relative soil moisture scale, and dry if the BRSM was less than (corresponding to mesic or submesic sites in DeLong s (00) moisture regime key). When stands were classified as

13 0 0 a (mesic), vegetation and soil characteristics were used to separate wet versus dry BRSM categories. When identifying the leading species (LEAD), a stand was determined leading in cedar (Cw), hemlock (Hw), or spruce (Sx), based on the tree species that had the highest Basal Area in the stand (to be consistent with VRI classification methodology). We tested thirteen combinations of independent variables that served as plausible explanatory hypotheses for the distribution of each lichen species:.brsm X OPEN X TEMP X PRECIP;. BRSM X OPEN X TEMP X SOLAR;. BRSM X PRECIP;. BRSM X TEMP;. LEAD X BRSM;. LEAD X OPEN X TEMP;. LEAD X OPEN X PRECIP;. LEAD X OPEN X SOLAR;.LEAD X PRECIP; 0. LEAD X TEMP;. OPEN X PRECIP X SOLAR X TEMP;. OPEN X PRECIP;.OPEN X TEMP. We used Akaike s Information Criterion with a correction for small sample size (AIC c ) (Johnson and Omland 00) to identify the most parsimonious logistic regression model. All AIC c values were subtracted from the lowest AIC c value in each model set to derive the AIC difference (AIC c dif). We then calculated the AIC c weights (AIC c w) and interpreted this value as the approximate probability that the model with the largest value was the most parsimonious of the set (Johnson and Omland 00). We calculated the area under the Receiver Operating Characteristic (ROC) curve for the top-ranked models (Munoz and Felicisimo 00). ROC scores allowed us to evaluate the ability of the most parsimonious model to predict the distribution of lichens on the landscape. We used Multi-Model Inference (MMI) to determine the relative importance of the predictor variables for each species (Johnson and Omland 00). MMI uses the AIC c w to average the coefficients from all variables within the set of models for each

14 0 0 lichen species and thus accounts for variation attributed to model selection uncertainty. We used % confidence intervals, corrected for model selection uncertainty, to assess the strength of effect of each predictor covariate on the dependent variable. RESULTS Of the species and genera (Melanelia spp. and Parmelia spp.) of arboreal lichens surveyed within the study plots, we found that of the cyanolichens were more frequent and occurred with greater abundance in stands that had wet BRSM conditions (Table ). The only exception to this pattern was the cyanolichen Nephroma resupinatum, which occurred infrequently ( sites), but abundantly (greater than 0 thalli/site) in both wet and dry stands. The chlorolichens occurred with relatively even frequency and abundance between stands with wet and dry soil moisture conditions, the noticeable exception being Cavernularia hultenii, which had a much higher frequency of occurrence in stands with wet BRSM conditions. Stand ordinations showed clustering of bipartite cyanolichens in the upper left quadrant of the plot (Fig. ). This included regionally rare species such as Lobaria retigera and Nephroma occultum to the more commonly abundant bipartate cyanolichens such as Nephroma isidiosum, Pseudocyphellaria anomala, and Sticta fuliginosa. The tripartite cyanolichen Lobaria pulmonaria, was found widespread throughout the ordination, although it displayed some tendency of increasing abundance in the upper left quadrant of the plot (Fig. ). Most of the chlorolichens were widely distributed, showing no strong placement preference along the two ordination axes. Temperature and precipitation were significantly correlated with both axis and axis ordination scores (Table ). When fit to a linear regression, data for Axis

15 0 0 demonstrated the best fit (R = 0.), with the variables relative soil moisture (P = 0.00), temperature (P = 0.00), canopy openness (P = 0.00), precipitation (P = 0.00), and basal area of spruce (P = 0.0) accounting for a significant proportion of the variation. Only temperature (P = 0.00) and precipitation (P = 0.0) were correlated with Axis ordination scores (R = 0.). Mean annual temperature, relative soil moisture, basal area, and canopy openness co-varied (Table ). When fitting and assessing the suite of logistic regression models we noted few similarities among the old-growth associated lichen species (Table ). The exceptions were N. occultum and C. hultenii, for which the best predictive models consisted of leading tree species and wet or dry BRSM status (although these two lichens selected for different leading tree species). The variables associated with the most parsimonious models for each lichen species were: temperature ( species), leading tree species ( species), relative soil moisture condition ( species), openness ( species), and precipitation ( species) (Table ). ROC scores ranged from 0. (P. norvegica) to 0. (N. isidiosum), indicating a good to excellent fit for each of the lichen species (Table ). Averaged coefficients suggested that all variables, other than precipitation and insolation, had some influence (positive or negative) on the distribution of one or more old-growth associated lichen species (Fig. ). Dry BRSM status had a 0 to negative effect on the presence of the eight lichen species, and wet BRSM status showed positive effects (both with relatively small confidence intervals). Canopy openness (OPEN) showed 0 or slightly positive effects. The temperature variable had the largest effect on the distribution of N. isidiosum or S. oroborealis, though confidence intervals were quite

16 0 0 large. In combination with temperature and/or BRSM, L. retigera, P. norvegica, and S. oroborealis showed greatest affinities to stands leading in hemlock and to a lesser degree cedar. C. hultenii, a chlorolichen, was related almost exclusively to hemlock and negatively to both cedar and spruce leading stands whereas N.occultum, a cyanolichen, showed preference to cedar dominated forests and a negative association with both hemlock and spruce dominated forests. Spruce had either no effect or a negative influence on the presence of the lichen species we tested. As with temperature, confidence intervals were often quite large for leading tree species (Fig. ). DISCUSSION The first major question of our study was whether distinct assemblages of oldgrowth dependant foliose macrolichens were distributed equally across an old-growth forest landscape of Inland Temperate Rainforest (ITR). A homogenous distribution of lichens would suggest that arboreal lichens do not respond to stand characteristics other than the criteria of reaching ages of 0 years or older. Our ordination plots show a clear assemblage of lichen species within a representative subset of old-growth forests greater than 0 years of age. These assemblages occurred mostly at low elevations with topography that favored the accumulation of soil moisture. Of the old-forest associated species identified by Campbell and Fredeen (00) the following more regionally rare species, C. hultenii, L. hallii, N. isidiosum, and N. occultum, were either limited to or more frequent and abundant in stands with wet BRSM conditions. Other old-growth associated lichens designated by Campbell and Fredeen (00), such as H.rugosa, H.vittata, L. scrobiculata, N. helveticum, N. parile, P. anomala and S. fuliginosa, were more widely distributed in our old forest stands, but were still far more abundant on wet

17 0 0 BRSM sites. A third set of old-growth associated lichens identified by Campbell and Fredeen (00), chlorolichen species such as Hypogymnia rugosa and P. norvegica, were widely distributed in both wet and dry stands greater than 0 years of age. From these results, we can identify an appropriate use of macrolichens as indicators at this regional scale. First, the presence and high abundance of L. pulmonaria across most of our research sites (wet or dry) proved to not be highly sensitive to sitespecific conditions and lichen diversity in our study area (as suggested by Campbell and Fredeen (00). This result concurs with Kalwij et al. (00) that suggested that L.pulmonaria at the site level is not sensitive to landscape disturbances, but could be a useful indicator of lichen diversity and disturbance frequencies when comparing among regional landscapes. We postulate that within regional landscapes, the presence and abundance of bipartate cyanolichens would serve as more appropriate indicators of potential biodiversity hotspots (sensu Bergamini et al. 00), canopy microclimate conditions (Stevenson and Coxson 00) and site disturbances (Goward ). We must caution, however, that the proliferation of a guild of bipartite cyanolichen species is a reflection of individual species ability to disperse and persist at a particular site. Therefore, while we may identify that L.retigera and N.occultum are both found in greater numbers and frequencies in sites of wet BRSM, we must also be aware that covarying ecological attributes found in wet BRSM (i.e., soil moisture, temperature, and site disturbance) could influences the presence of these regionally rare macrolichens differently. Our data suggests that sites of wet BRSM status are biodiversity hotspots due to a combination of optimal microclimatic conditions (due to lichen establishment limitations) and potential stand continuity (due to lichen dispersal limitations).

18 0 0 Although Glavich et al. (00) pointed to temperature and moisture as major predictors of cyanolichen diversity over a vast region of coastal wet temperate rainforests, our correlation of environmental attributes with ordination scores suggests that gradients of temperature and moisture play an important role in shaping cyanolichen assemblages at finer scales of distribution. Temperature has long been inferred as an important environmental variable in structuring ITR cyanolichen communities. Canopy cyanolichens rapidly diminish in abundance as stand composition shifts from cedarhemlock to spruce-fir with increasing elevation (Goward ). Studies on cyanolichen physiology suggest that processes of carbon assimilation and nitrogen fixation are highly rate-limited at low temperatures (Sundberg et al. ). Interactions with precipitation, which can be viewed as a proxy for the duration of thallus hydration, are also fairly straightforward. Lichen growth models are highly sensitive to the duration of physiological activity (Sundberg et al. ). Coxson and Stevenson (00) showed that most growth in L. pulmonaria populations from the ITR coincides with precipitation events in the spring and summer (the exception being some snowmelt events in the early spring). Although thalli are often hydrated for long time periods in the late fall and winter, they are commonly frozen and experience very low light availability, and hence cannot realize much growth potential. The opposing trends in temperature and precipitation with increasing elevation in ITR mountain valleys would appear to have major constraints on the establishment of canopy cyanolichens. However, site moisture and relative humidity are not related solely to precipitation. The amount of slope above a position on the landscape is a major factor in determining site moisture (Campbell and Coxson 00). Relative soil moisture status

19 0 0 was significantly correlated with axis of the NMS ordination and was a significant variable in a majority of best model sets predicted by logistic regression for individual species. Where wet BRSM status coincides with warmer valley bottom conditions, lichen communities escape the constraints that would otherwise be placed on their development by regional gradients of temperature and precipitation. We hypothesize that the greater relative humidity found within the lower canopy of these stands extends the duration of periods of metabolic activity experienced by canopy lichens after precipitation events. This, in combination with the form in which the precipitation falls (i.e., rain versus snow), would identify more optimal habitat particularly for cyanolichens, which need direct contact with water to resume physiological activity (Budel and Lange ). This is evident where one finds adjacent dry BRSM stands with much lower canopy lichen diversity, notwithstanding very similar exposure to temperature and absolute precipitation. Old-forest stands that develop in wet BRSM areas tend to share many common attributes. Basal areas of cedar, fir, and spruce are greater, presumably reflecting the influence of subsurface water on tree growth, and indirectly, the greater exclusion of fire as a major natural disturbance agent (Eng 000, Beaty and Taylor 00). Importantly, wet stands tended to have a more open canopy structure, reflecting the greater role of gap dynamics within old-forest stands in water-receiving positions (Benson and Coxson 00, Lertzman et al. 00, Radies and Coxson 00). For canopy cyanolichens, this combination of abundant light in a humid lower canopy environment creates ideal conditions for growth and establishment (Coxson and Stevenson 00). Spies and Franklin () postulated that receipt of groundwater flow and attendant transfer of

20 0 0 nutrients was a major determinant of the overall growth, development and structure of coastal wet temperate rainforests. Spies et al. (00) further pointed out the importance of recognizing these site-specific factors when developing plans for the conservation of old-growth forests. Conversely, higher fire return intervals on upslope positions, particularity those of south-facing aspects (Eng 000), have most likely limited the accumulation of rare lichen species due to both dispersal limitations (Sillett et al 000) and unfavorable site and structural characteristics for lichen establishment (as discussed). Our second major question was whether old-growth lichens, when examined individually, would select similar environmental variables. The same variables played an important role in predicting the presence or absence of individual species. All of the so-called old-growth associated lichen species had either temperature or BRSM as major predictive variables in their best model sets (> 0. Akaike s weight), with of these species having both predictor variables present. However, of the species, only species shared similar parsimonious models and demonstrated varying affinities to leading old-growth stand type indicating habitat limitations for some lichen species across our study area and the importance of stand representation. Presence of the endangered cyanolichen species N. occultum was predicted best by wet cedar-leading stands. Evidence suggests that undisturbed wet cedar-leading stands have persisted for time periods well in excess of the age of the oldest trees, fulfilling definitions of antique forest stands (Goward and Arsenault 000). This suggests that N. occultum is most likely dispersal limited, proliferating only in stands that reach exceptional ages. Thalli of N. occultum, however, may also be influenced by greater nutrient availability in water receiving (wet BRSM) stands. These sites receive 0

21 0 0 groundwater flow from upslope catchment areas, potentially representing a landscape level transfer of soluble nutrients. Further, on sites where cedar dominates, enrichment of exchangeable soil calcium can occur through deposition of CaCO in litterfall (Graff et al. ), a potentially important factor in subsequent enrichment of throughflow precipitation as it passes over canopy foliage. Most of the old-growth associated lichens that selected for leading species also demonstrated wide confidence intervals around the respective coefficients. These large intervals can be explained by the broad autoecological requirements of individual species themselves and/or the broad scale at which forest stands were measured (in this case, leading stand type). Importantly, our measurement of leading-tree species does not identify the gradient of mixed conifer forest of cedar, hemlock, spruce and fir most often found in these forest types. However, the association of lichens within this gradient of mixed stand types could help explain the similar positive influence of both cedar and hemlock leading forests on the presence of L. retigera, P.norvegica, and S. oroborealis. This finding also suggests a broader ecological tolerance to stand conditions by certain old-growth associated lichens, but not for all. From the perspective of setting priorities for the conservation of canopy lichen communities, the retention of representative old-forest stands in areas of water-receiving valley bottom positions should be a high priority for land-use planners. This strategy will also ensure old-growth ITR landscapes are more resilient by mimicking natural disturbance regimes (sensu Drever et al. 00) and protecting regions of temperate mountain coniferous forests less prone to fire disturbance such as north-facing aspects (Eng 000), moderate slope terrain, and valley bottom locations (Beaty and Taylor 000).

22 0 0 We also suggest that forest harvesting practices in these regions needs to be more complex including variable retention single tree and small patch cuts that reflect the natural range of variability in disturbance events that characterizes these wet old-growth forest systems (Lertzman et al 00, Radies and Coxson 00). Across dry BRSM sites, particularly those areas more prone to both insect outbreak and fire, clearcut harvesting may be a more suitable prescription. We emphasize that harvesting strategies must recognize spatial and temporal scale and pattern discrepancies between wet and dry BRSM forest types. Ecosystem-based forest management would not borrow disturbance patterns from one moisture type and prescribe it to another (i.e., frequent clear-cuts in wet BRSM sites). Current spatial representation of old-forests in protected areas in the ICHvk is approximately %, well below the ecosystem-based threshold target of % set for the upper Fraser River watershed (Anonymous 00). Given that many of the rare lichens were only found in one or two wet sites (and not the same ones), it is highly unrealistic to expect that current protected areas will maintain canopy lichen diversity within regional landscapes. Furthermore, continued clear-cut forest harvesting in representative wet, low elevation old-growth forest stands, will likely ensure a greater loss of macrolichen biodiversity prior to reaching regionally set ecosystem-based old-growth threshold targets (Anonymous 00). Indeed, past harvesting of old-forest stands in wet BRSM sites may already have incurred an extinction debt (Berglund and Jonsson 00) in the upper Fraser ITR.

23 0 Conclusions The application of indicator species requires an understanding of both the natural history of the organism and the appropriate use of scale and measurement. Our data suggest that at site-specific scales in mountainous old-growth ITR, bipartate cyanolichens could prove useful in the determination of areas of high biological value due to both optimal site conditions (relating to lichen establishment) and potential longevity of the stand itself (relating to lichen dispersal). Given the reduction in the total area of these site types due to anthropogenic activities, we recommend that old-forest stands in the upper Fraser River watershed that have wet BRSM status be given immediate consideration for protected area status. These sites represent significant biodiversity hotspots for canopy lichens that are essential for the maintenance of biodiversity within larger regional landscapes. The distribution of these organisms highlights the importance of appropriately identifying soil moisture site discrepancies in old-growth forests for the purposes of executing effective ecosystem-based management thresholds and strategies. Therefore, when applying old-growth thresholds to temperate old-growth rainforests, the question, how much is really enough? (Price et al. 00), must also be coupled with, of what kind, in what location, and in what context?. Otherwise, the objective of setting thresholds targets for the purposes of maintaining biodiversity will most likely miss its mark. 0

24 ACKNOWLEDGEMENTS We are grateful to M.E. Gauthier, C. Helenius, J. Kelly, D. Khurana and C. LeBoutier for assistance with fieldwork. We thank S. Stevenson, P. Sanborn and C. DeLong for reviews of draft manuscripts and assistance with the development of methods; T. Goward for assistance with lichen identifications; and J. Campbell for review of the final manuscript draft. The Canadian Forest Service supplied climate data. The Sustainable Forest Management Network, the B.C. Forest Science Program, Mountain Equipment Coop, and the University of Northern B.C provided funding.

25 0 0 LITERATURE CITED Anonymous.. Vegetation Resources Inventory: Implementation strategy to integrate management, provincial and national inventories. Resources Inventory Branch, B.C. Ministry of Forests, Victoria, B.C. Available at: < Anonymous.. Standards for Predictive Ecosystem Mapping, version.0. The resources inventory committee, Province of B.C, Victoria, B.C. Available at: < Anonymous. 00. Order establishing provincial non-spatial old-growth objectives. Government of B.C. Integrated Land Management Bureau. Available at: < Anonymous. 00. Old forest retention results to March, 00. Prince George Public Advisory Group. Unpublished report. B.C. Ministry of Forests. Prince George, B.C. Arsenault, A. and T. Goward Ecological characteristics of inland rainforests. Ecoforestry : 0-. Beaty, R.M. and A.H. Taylor. 00. Spatial and temporal variation of fire regimes in a mixed conifer forest landscape, Southern Cascades, California, USA. Journal of Biogeography :-. Benson, S., and D.S. Coxson. 00. Lichen colonization and gap structure in wettemperate rainforests of northern interior British Columbia. The Bryologist 0:-.

26 0 0 Bergamini, A., Scheidegger, C., Stoffer, S., Carvalho, P., Davey, S., Dietrich, M., Dubs, F., Farkas, E., Groner, U., Kärkkäinen, K. Rkkäinen, K., Keller, C., Lökös, L., Lommi, S.,Máaguas, C., Mitchell, R., Pinho, P., Rico, V.J., Aragón, G., Truscott, A.M., Wolesly, P. and A. Watt. 00. Performance of macrolichens and lichen genera as indicators of lichen species richness and composition. Conservation Biology :0 0 Berglund, H., and B.G. Jonsson. 00. Verifying an extinction debt among lichens and fungi in northern Swedish boreal forests. Conservation Biology :-. Budel, B., and O.L. Lange. Water status of green and blue green phycobiots in lichen thalli after hydration by water vapour uptake? Do they become turgid? Botanica Acta 0:-. Campbell, J., and D.S. Coxson. 00. Canopy microclimate and arboreal lichen loading in subalpine spruce-fir forest. Canadian Journal of Botany :-. Campbell J, and A.L. Fredeen. 00. Lobaria pulmonaria abundance as an indicator of macrolichen diversity in Interior Cedar hemlock forests of East-Central British Columbia. Canadian Journal of Botany :0-. Castellón, T.D., and K.E. Sieving. 00. Patch network criteria for dispersal-limited endemic birds of South American temperate rain forest. Ecological Applications :-. Coast Information Team. 00. EBM Planning Handbook. Available at <

27 0 0 Coxson, D.S., and S.K. Stevenson. 00. Growth rate responses of Lobaria pulmonaria to canopy structure in even-aged and old-growth cedar-hemlock forests of centralinterior British Columbia, Canada. Forest Ecology and Management :-. DeLong, S.C.. Natural disturbance rate and patch size distribution of forests in northern British Columbia: Implications for forest management. Northwest Science :-. DeLong, S.C. 00. A field guide for site identification and interpretation for the southeast portion of the Prince George Forest Region. Research branch, B.C. Ministry of Forests, Victoria, B.C. Land Management Handb. No. DeLong, S.C. 00. Implementation of natural disturbance-based management in northern British Columbia. Forestry Chronicle :-. Drever, C.R., Peterson, G., Messier, C., Bergeron, Y., and M. Flannigan. 00. Can forest management based on natural disturbances maintain ecological resilience? Canadian Journal of Forest Research :-. Eng, M Fire analysis for the Robson Valley Forest District. Unpublished Report. Research Branch. Ministry of Forests. Victoria, B.C. < Fazey, I, Fisher, J., and D.B. Lindenmayer. 00. What do conservation biologists publish? Biological Conservation :-. Glavich, D.A., L.H. Geiser, and A.G. Mikulin. 00. Rare epiphytic coastal lichen habitats, modeling, and management in the Pacific Northwest. The Bryologist 0:-0.

28 0 0 Goward, T.. Notes on old-growth dependent epiphytic macrolichens in inland British Columbia, Canada. Acta Botanica Fennica 0:-. Goward, T. 00. Lichens of the Robson Valley provincial parks: Grizzly-Sugarbowl, West Twin Creek, Slim Creek. Unpublished report. B.C. Parks. Prince George. Goward, T., and A. Arsenault Inland old-growth rain forests: safe havens for rare lichens? In Darling, L.M. (editor). Proceedings, Biology and Management of Species and Habitats At Risk, Kamloops, B.C., - February. B.C. Min. Environ., Lands and Parks, Victoria, B.C. and University College of the Cariboo, Kamloops, B.C:-. Goward, T. and A. Arsenault. 00. Notes on the Populus "dripzone effect" in well ventilated stands in humid inland east-central British Columbia. The Canadian Field-Naturalist :-. Goward, T., McCune, B., and D.V. Meidinger.. The Lichens of British Columbia Illustrated Keys Part : Foliose and Squamulose Species. B.C. Ministry of Forests, Research Branch. Special Report Series. Goward, T., and T. Spribille. 00. Lichenological evidence for the recognition of inland rainforests in western North America. Journal of Biogeography :0-. Graff, J.E., R.K. Hermann, and J.B. Zaerr.. Ionic balance and organic acids in western redcedar, western hemlock, and Douglas-fir seedlings grown in low- and high-n soils. Canadian Journal of Forest Research :-. Hutchinson, M. F.. Interpolating mean rainfall using thin plate smoothing splines. International Journal of Geographical Information Systems :-0.

29 0 0 Hyvärinen, M., P. Halonen, and M. Kauppi.. Influence of stand age on the epiphytic lichen vegetation in the middle-boreal forests of Finland. The Lichenologist :-0. Iverson, L.R., Martin, E.D., Scott, C.T. and A. Prasad A GIS-derived integrated moisture index to predict forest composition and productivity of Ohio forests (U.S.A.). Forest Ecology and Management :-00 Johnson, J.B. and Omland, K.S. 00. Model selection in ecology and evolution. Trends in Ecology and Evolution :0-0. Kalwij, J.M., Wagner, H.H., and C. Scheidegger. 00. Efferts of stand-level disturbances on the spatial distribution of a lichen. Ecological Applications :0 0. Ketcheson, M.V., T.F. Braumandl, D. Meidinger, G. Utzig, D.A. Demarchi, and B.M. Wikeem.. Interior cedar-hemlock zone. In Ecosystems of British Columbia, Meidinger, D., and Pojar, J., eds. Ch. BC Ministry of Forests, Special Report Series No.. Kew, M.. Salmon availability, technology, and cultural adaptation in the Fraser River Watershed. In: A Complex Culture of the British Columbia Plateau. Traditional Stl'atl'imx Resource Use. Edited by B. Hayden. UBC Press, Vancouver, B.C.. Kitching, R.L., Bergelson, J.M., Lowman, M.D., McIntyre, S., and G. Carruthers.. The biodiversity of arthropods from Australian rainforest canopies: General introduction, methods, sites and ordinal results. Australian Journal of Ecology :-.

30 0 0 Lertzman, K., Gavin, D., Hallett, D., Brubaker, L., Lepofsky, D. and R. Mathewes. 00. Long-term fire regime estimated from soil charcoal in coastal temperate rainforests. Conservation Ecology < Lidén, M. and O. Hilmo. 00. Population characteristics of the suboceanic lichen Platismatia norvegica in core and fringe habitats: Relations to macroclimate, substrate, and proximity to streams. The Bryologist 0:0. McCune, B., and M.J. Mefford.. PC-ORD. Multivariate analysis of ecological data. Version.0. MJM Software, Glenden Beach, Oregon, U.S.A.. McCune, B., R. Rosentreter, J.M. Ponzetti, and D.C. Shaw Epiphyte habitats in an old conifer forest in western Washington, U.S.A. The Bryologist 0:-. McCune, B., J. Hutchinson, and S. Berryman. 00. Concentration of rare epiphytic lichens along large streams in a mountainous watershed in Oregon, U.S.A. The Bryologist 0:-0. Menard, S. 00. Applied Logistic Regression Analysis. Second Edition. Sage Publications Inc., California. Moola, F.M., D. Martin, B. Wareham, J. Calof, C. Burda, and P. Grames. 00. The coastal temperate rainforests of Canada: The need for ecosystem-based management. Biodiversity :-. Munoz, J. and A. Felicisimo. 00. Comparison of statistical methods commonly used in predictive modelling. Journal of Vegetation Science :-. Negi, R.N. and M. Gadgil. 00. Cross-taxon surrogacy of biodiversity in the Indian Garhwal Himalaya. Biological Conservation 0:-. 0

31 0 0 Niemi, G.J. and M.E. McDonald. 00. Application of ecological indicators. Annual Review of Ecology, Evolution, and Systematics :-. Pastor, J., M. and W.M. Post.. Influence of climate, soil moisture, and succession on forest carbon and nitrogen cycles. Biogeochemistry :-. Price, K., Holt, R.F., and L. Kremsater. 00. How much is really enough?: Informing old growth targets with threshold science. Conservation Biology (in submission). Radies, D. N., and D.S. Coxson. 00. Macrolichen colonization on 0-0 year old Tsuga heterophylla in wet temperate rainforests of central-interior British Columbia: a comparison of lichen response to even aged versus old-growth stand structures. The Lichenologist :-. Reynolds, R.R.. Climatic data summary for the biogeoclimatic zones of British Columbia. British Columbia Ministry of Forests, Research Branch. Unpublished Report. Victoria, B.C. Sanborn, P., M. Geertsema, A.J.T. Jull, and B. Hawkes. 00. Soil and sedimentary charcoal evidence for Holocene forest fire in an inland temperate rainforest, eastcentral British Columbia, Canada. Holocene :-. Sillett, S.C., B. McCune, J.E. Peck, T.R. Rambo, and A. Ruchty Dispersal limitations of epiphytic lichens result in species dependent on old-growth forests. Ecological Applications 0:. Spies, T.A., and J.F. Franklin.. The structure of natural young, mature, and oldgrowth Douglas-Fir Forests in Oregon and Washington. Published by: U.S. Department of Agriculture, Forest Service Pacific Northwest Research Station Portland, Oregon General Technical Report PNW-GTR-.

32 0 Spies, T.A, M.A. Hemstrom, A. Youngblood, and S. Hummel. 00. Conserving oldgrowth forest diversity in disturbance-prone landscapes. Conservation Biology 0:-. Stevenson, S.K., H.M. Armleder, M.J. Jull, D.G. King, B.N. McLellan, and D.S. Coxson. 00. Mountain caribou in managed forests: recommendations for managers: Second Edition. B.C. Min. Environ., Lands, and Parks. Wildlife Rep. No. R-. Victoria, B.C. Stevenson, S.K., and D.S. Coxson. 00. Edge effects on Lobaria retigera in B.C. s inland temperate rainforest. Forest Ecology and Management (in-submission). Sundberg, B., K. Palmqvist, P.A. Esseen, and K.E. Renhorn.. Growth and vitality of epiphytic lichens. II. Modelling of carbon gain using field and laboratory data. Oecologia 0:0-. Turner, G.T.. Landscape Ecology: The Effect of Pattern on Process. Annual Review of Ecology and Systematices 0:-. Walker, B.H.. Biodiversity and ecological redundancy. Conservation Biology :-. Zinko, U., Seibert, J., Dynesius, M., and C. Nilsson, C. 00. Plant species numbers predicted by a topography-based groundwater flow index. Ecosystems :0-. 0

33 Table. Macrolichen presence/absence by number of sites containing each species and abundance distribution (in brackets) in the upper Fraser River watershed. Abundances denote frequency of occurrence of each species based on a three point scale: very low equals - thalli, low equals -0 thalli, and common equals more than 0 thalli per site. One exception, is L. pulmonaria*, which was measured by number of handful sizes (0 x 0 cm ) as opposed to thalli measurements. Dry Stand Plots Wet Stand Plots Species ( sites total) ( sites total) Number of site occurrences and occurrences by abundance scale: very low (VL), low (L), common (C) CHLOROLICHENS # of dry sites (VL, L, C) # of wet sites (VL, L, C) Cavernularia hultenii (,,0) (,,) Cetraria cetroides 0 (,0,0) Hypogymnia austerodes (,0,0) (,0,0) H. bitteri (,,) (,,) H.imshaugii 0 (,0,0) H. metaphysodes (,,) (,,) H.occidentalis (0,,) (0,0,) H.oroborealis (,0,0) (,0,0) H. physodes (0,0,) (0,0,) H. rugosa (,,) 0 (,0,) H. tubulosa (0,,) (0,,)

34 H. vittata (,,0) (0,,) Melanelia spp. (,,) (,,) Parmelia spp. (0,0,) (0,0,) Parmeliopsis ambigua (,,) (,,) P. hyperopta (,,) (,,) Platismatia glauca (0,0,) (0,0,) P. norvegica (,,) (,,) Tuckermannopsis chlorophylla (,,) (,,) T. orbata (,,) (,0,0) Vulpicida pinastri (,,) (,,) CYANOLICHENS # of dry sites (VL, L, C) # of wet sites (VL, L, C) Leptogium burnetiae 0 (,0,0) L. saturninum (,0,) (,0,) Lobaria hallii 0 (,0,0) Lobaria pulmonaria* (,,) (0,0,) Lobaria retigera (,0,0) (,,) Lobaria scrobiculata (,,) (,0,) Nephroma bellum (,,) (,,) Nephroma helveticum (,,) (0,,) Nephroma isidiosum (,,) (,,) Nephroma occultum (,0,0) (0,, 0) Nephroma parile (,,) (0,,)

35 Nephroma resupinatum (0,,0) (0,0,) Peltigera collina (0,,0) (,,0) Polychidium dendriscum 0 (,,) Pseudocypellaria anomala (,,) (,,) Sticta fuliginosa (0,,) (,,) Sticta limbata 0 (,0,0) Sticta oroborealis (,,) (,,) Sticta wrightii (,0,0) (,0,0)

36 Table. Multiple linear regression estimates for the log-transformed environmental variables temperature, precipitation (mean minimum temperature, March to October), solar loading, canopy openness, relative soil moisture, and basal area of cedar (Cw), hemlock (Hw), spruce (Sx), and fir (Sf) calculated against Axis (R = 0., f-ratio =., P < 0.00) and Axis (R = 0., f-ratio =.0, P < 0.00) ordination scores (n = ) Variable Coefficient SE t P AXIS CONSTANT Temperature < 0.00 Precipitation Solar Loading Basal Area (Hw) Basal Area (Cw) Basal Area (Sx) Basal Area (Sf) Relative Soil Moisture Canopy Openness AXIS CONSTANT Relative Soil Moisture Temperature

37 Canopy Openness Precipitation Basal Area (Sx) Basal Area (Hw) Solar Loading Basal Area (Sf) Basal Area (Cw)

38 Table. Mean and standard deviation of stand variables. N = and respectively for dry and wet broad relative soil moisture (BRSM) stands in the upper Fraser River watershed. Stand Stand Variables Type Mean Minimum Annual Solar Loading % Canopy Temperature Mar.-Oct. Precipitation (kwh/m ). Openness. ( C). Temperature (mm). ( C). Mean SD Mean SD Mean SD Mean SD Mean SD DRY WET Stand Stand Variables Type Stand Basal Basal Area Basal Area Basal Area Basal Area Area Fir Cedar Hemlock Spruce (m / ha). (m / ha). (m / ha). (m / ha). (m / ha). Mean SD Mean SD Mean SD Mean SD Mean SD DRY WET

39

40 Table. Predicted best model sets (> 0. AIC c w) for presence of the old-forest associated macrolichens and receiver operating characteristic (ROC) results for best models in the upper Fraser River watershed. Abbreviations for model variables are as follows: broad relative soil moisture (BRSM); leading tree species (LEAD); canopy openness (OPEN), mean annual precipitation (PRECIP) and; mean minimum temperature, March October (TEMP). Abbreviations in brackets cedar (Cw), hemlock (Hw) and wet BRSM (wet) represent categorical variables with greatest influence. Species Best Model Sets (>0. AIC c w) AIC c w ROC Cavernularia hultenii LEAD (Hw) X BRSR (wet) Lobaria retigera LEAD (Hw) X OPEN X TEMP Nephroma isidiosum BRSM (wet) X OPEN X TEMP X PRECIP Nephroma occultum LEAD (Cw) X BRSM (wet) Platismatia norvegica LEAD (Hw) X TEMP Peltigera collina BRSM (wet) X TEMP Sticta fuliginosa OPEN X TEMP Sticta oroborealis LEAD (Hw) X OPEN X TEMP

41 0 0 Figure Legends. Figure. Landscape distribution of old-growth cedar, hemlock, and spruce-leading forests (separated by both wet and dry broad relative soil moisture conditions) in the very wet cool Interior Cedar Hemlock (ICHvk) and adjacent very-wet cool Sub-Boreal Spruce (SBSvk) biogeoclimatic zones of the upper Fraser River watershed. Forests north of the Fraser River are part of the Rocky Mountain formation, while forests south of the Fraser River are part of the Columbia Mountain formation. Insert indicates study location in British Columbia, Canada. Insert and identifies old-growth forest type on north and south-facing aspects of Driscoll ridge respectively. Reference points indicate plot-sampling locations. Figure. Overlay of species abundance in the upper Fraser River watershed in 00 on stand ordinations for the tripartate macrolichen Lobaria pulmonaria, and the bipartate cyanolichens: L. retigera, Sticta fuliginosa, Nephroma isidiosum, Nephroma occultum, and Pseudocyphellaria anomala Figure. Coefficients and % confidence intervals of independent variables for each of the eight old-growth associated lichen species in the upper Fraser River watershed generated using logistic regression. Abbreviations of variables as follows: dry relative soil moisture (dry); wet relative soil moisture (wet); canopy openness (Densio); mean minimum temperature (Temp); Mean annual precipitation (Precip); solar loading (Solar); cedar-leading (cw); hemlock-leading (hw); and spruce-leading (sx).

42 Figure.

43