Red-listed Lichens Research Articles

Practical conservation action on a Critically Endangered lichen species

To save a species on the verge of extinction, an urgent practical conservation action was performed on the Critically Endangered lichen species Leptogium hibernicum in Norway. A transplantation experiment at two localities was carried out in close cooperation with the responsible authorities. An alarming problem for L. hibernicum is the imminent challenge of a habitat under threat. A parallel experiment with a comparable yet common species, Leptogium saturninum, was performed to exclude variables related to the experimental method. Four years after transplantation of lichen fragments, the rate of survival has levelled off to about 12% for L. hibernicum and 19% for L. saturninum. The decrease in surviving material is largest one year after transplantation, while the amount of surviving material stabilises over the following three years. Transplantation is here shown as a promising tool for the practical conservation of red-listed lichens.

A biogeographical study of red listed lichen species at temporal and spatial scales within protected and non-protected areas

The present study is focused on the temporal and spatial distribution of red listed lichen (RLL) species identified in both non-protected areas (NPAs) and protected areas (PAs) in Romania. This study revealed different scenarios of RLL based on two major patterns: (1) the fate of RLL before and after their designation in the red list in Romania and (2) the fate of RLL before and after the designation of PAs in Romania. Generally, the occurrences of RLL were well represented in time and space in both NPAs and PAs through geomorphological and biogeographical units. In particular, the occurrences of RLL were well represented, especially in hilly areas within PAs before and after their official designation, and this was an important aspect over a long period of time. Although NPAs were not less important regarding the occurrences of RLL species, it was observed that they followed the same pattern as PAs, namely, they were well represented in hilly areas and over a long period of time. The bioregions were significant for RLL species in both NPAs (continental and stepic) and PAs (continental, panonic, and stepic). As a significant finding of this study, NPAs and PAs should be subjected to an adequate conservation regime due to their biotical traditional heritage.

VYTEGRA TOWN LICHEN SPECIES SUBJECT TO PROTECTION AND IN NEED OF BIOLOGICAL CONTROL IN THE VOLOGDA REGION

Information is provided on seven Vologda Region's red-listed lichen species discovered in the town of Vytegra, viz. Chaenotheca stemonea, Gyalolechia flavorubescens, Ramalina dilacerata, Ramalina farinacea, Ramalina pollinaria, Ramalina sinensis, and Xanthoria fallax s. l., and on two species in need of biological control, Melanelixia subargentifera and Parmelina tiliacea. Red-listed species were recorded from 17 locations, and species in need of biological control - from three. Red-listed lichen species were found on 15 woody species, 8 of them native and 7 alien. Most of the findings come from linden (Tilia cordata) and white poplar (Populus alba) trees over 100 years old, growing in the town's two historical parks - Culture and Recreation Park ('Summer Garden') and Children's Village. In these parks, 1-3 red-listed species were found on almost every old tree. Both parks are recognized as requiring a conservation status. The numerous later tree plantations, which are now some 45-50 years old, contain much fewer red-listed lichens, which either occur on singular trees or are absent in many localities. In semi-natural habitats, which are very few within Vytegra town administrative boundaries and occupy a small area, 4 red-listed species were found. The red-listed Chaenotheca stemonea, characteristic of old-growth forests, was found only in a remnant piece of a riparian spruce forest.

Cora timucua (Hygrophoraceae), a new and potentially extinct, previously misidentified basidiolichen of Florida inland scrub documented from historical collections

The known collections of the genus Cora in continental North America north of Mexico, all restricted to Florida, are shown to belong to a single species, representing a previously unrecognized taxon formally described herein as C. timucua. Based on data of the fungal ITS barcoding marker, obtained through Sanger and Illumina sequencing from two historical collections, the new species is phylogenetically most closely related to C. casanarensis from Colombia and C. itabaiana from Brazil, although it is morphologically most similar to the only distantly related C. hymenocarpa from Costa Rica. Based on data from the Consortium of North American Lichen Herbaria (CNALH) and from the Global Biodiversity Information Facility (GBIF), most of the collections of C. timucua originate from around the turn of the 19th century, while a few were made in the second half of the 20th century, all between 1968 and 1985. Almost all collections originate from Florida sand pine scrub, apparently the preferred habitat of this taxon. Neither modern collections nor extant localities are known. Based on these findings and the substantial degree of land use change in Florida in the past decades, we assessed the conservation status of C. timucua using the IUCN Red List criteria and found that it should be classified as critically endangered (CR), in line with the status of another Florida endemic, Cladonia perforata, which was the first federally red-listed lichen in the United States. The most likely location where C. timucua may still be extant is Ocala National Forest in the north-central portion of the Florida peninsula, although recent macrolichen surveys in that area did not encounter this species.

Epiphytes in wooded pastures: Isolation matters for lichen but not for bryophyte species richness.

Sylvo-pastoral systems are species-rich man-made landscapes that are currently often severely threatened by abandonment or management intensification. At low tree densities, single trees in these systems represent habitat islands for epiphytic cryptogams. Here, we focused on sycamore maple (Acer pseudoplatanus) wooded pastures in the northern European Alps. We assessed per tree species richness of bryophytes and lichens on 90 sycamore maple trees distributed across six study sites. We analysed the effects of a range of explanatory variables (tree characteristics, environmental variables and isolation measures) on the richness of epiphytic bryophytes and lichens and various functional subgroups (based on diaspore size, habitat preference and red list status). Furthermore, we estimated the effect of these variables on the occurrence of two specific bryophyte species (Tayloria rudolphiana, Orthotrichum rogeri) and one lichen species (Lobaria pulmonaria) of major conservation concern. Bryophytes and lichens, as well as their subgroups, were differently and sometimes contrastingly affected by the variables considered: tree diameter at breast height had no significant effect on bryophytes but negatively affected many lichen groups; tree phenological age positively affected red-listed lichens but not red-listed bryophytes; increasing isolation from neighbouring trees negatively affected lichens but not bryophytes. However, the high-priority bryophyte species T. rudolphiana was also negatively affected by increased isolation at small spatial scales. Orthotrichum rogeri was more frequent on young trees and L. pulmonaria was more frequent on trees with thin stems and large crowns. The results indicate that local dispersal is important for lichens, whereas long distance dispersal seems to be more important for colonisation by bryophytes. Furthermore, our study highlights that different conservation measures need to be taken depending on the taxonomic and functional species group or the individual species that is addressed. In practice, for the conservation of a high overall richness in sylvo-pastoral systems, it is crucial to sustain not only old and large trees but rather a wide range of tree sizes and ages.

Hidden crown jewels: the role of tree crowns for bryophyte and lichen species richness in sycamore maple wooded pastures

Tree crowns typically cover the vast majority of the surface area of trees, but they are rarely considered in diversity surveys of epiphytic bryophytes and lichens, especially in temperate Europe. Usually only stems are sampled. We assessed the number of bryophyte and lichen species on stems and in crowns of 80 solitary sycamore maple trees (Acer pseudoplatanus) at six sites in wooded pastures in the northern Alps. The total number of species detected per tree ranged from 13 to 60 for bryophytes, from 25 to 67 for lichens, and from 42 to 104 for bryophytes and lichens considered together. At the tree level, 29 % of bryophyte and 61 % of lichen species were recorded only in the crown. Considering all sampled trees together, only 4 % of bryophyte, compared to 34 % of lichen species, were never recorded on the stem. Five out of 10 red-listed bryophyte species and 29 out of 39 red-listed lichen species were more frequent in crowns. The species richness detected per tree was unexpectedly high, whereas the proportion of exclusive crown species was similar to studies from forest trees. For bryophytes, in contrast to lichens, sampling several stems can give a good estimation of the species present at a site. However, frequency estimates may be highly biased for lichens and bryophytes if crowns are not considered. Our study demonstrates that tree crowns need to be considered in research on these taxa, especially in biodiversity surveys and in conservation tasks involving lichens and to a lesser degree also bryophytes.

Large beech (Fagus sylvatica) trees as ‘lifeboats’ for lichen diversity in central European forests

The forest management practices used in central Europe in the last several centuries have led to loss of lichen diversity that may be largely attributed to a loss of substrate variability and quantity. In an attempt to obtain information enabling us to mitigate this process, we surveyed affinity of lichen species to the substrates they currently occupy in six forest areas in the Czech Republic, located between 200 and 1000 m a.s.l. Tree bases and stems represented the most important substrate for lichen species, and especially so for threatened (i.e. red-listed) species. Lichen species richness per individual tree generally increased with stem diameter, especially for beech. Stems and tree bases of large-diameter beeches provide habitats that have enabled the survival of a crucial component of the red-listed lichen species in central Europe, far outweighing other tree species. The deciduous tree species that are commonly considered as favourable for lichen diversity (e.g. maples, ash, elms) were inhabited by only a few other lichen species additional to those associated with beech. This may be due to the low frequency of these tree species in most managed forests, and also some forest reserves, at the present time. Similarly, low incidence of dead wood in managed forests has likely limited its contribution to the lichen diversity, despite the high potential for lichen diversity associated with such substrates. It is thus apparent that bark of large-diameter live beech trees comprises a keystone habitat element in the provision of lichen diversity in central European forests.

Local dispersal dynamics determine the occupied niche of the red-listed lichen Seirophora villosa (Ach.) Frödén in a Mediterranean Juniperus shrubland

The red-listed lichen Seirophora villosa is associated with undisturbed coastal dune systems dominated by Juniperus spp. The clustered distribution of this species suggests that propagative traits may be responsible for its conservation status. We tested whether the local distribution of an S. villosa population under undisturbed conditions is limited by habitat filtering or by low dispersal fitness. Using Strip Adaptive Cluster Sampling, we estimated the size of one of the largest undisturbed Italian populations of S. villosa . We considered the abundance of both mature and juvenile thalli in relation to geographical and environmental spaces. Multiple regression on distance matrices models were in accordance with the hypothesis that S. villosa is occupying only a small portion of its colonizable niche because of a very limited propagation ability. Apart from the co-occurrence of mature thalli, the presence of juvenile thalli was independent of pure spatial and environmental factors. • In the studied population of the lichen S. villosa mature thalli were rare. • S. villosa showed a very limited propagation ability. • The effect of habitat filtering is negligible.

Epiphytic lichen conservation in the Italian Alps: the role of forest type

Epiphytic lichens are a functionally important and species-rich component of Alpine forests, including several species of conservation concern. Their dependence on specific host trees predicts that forests with different tree species composition host different lichen communities, enhancing lichen diversity in forest landscapes. In this study, we tested for the first time the effect of forest type on patterns of epiphytic lichen diversity, in the Italian Alps. We sampled the main forest types of the South Tyrol, a typical Alpine region of Italy. We also assessed the influence of factors related to forest structure and climatic conditions. Our results demonstrate that different forest types host statistically different lichen communities, suggesting that the conservation of lichen diversity is entrusted to the maintenance of forest landscape heterogeneity, including forest types of minor economic value and rural habitats. The highest number of species was found in grazed larch forests and in high-elevation spruce forests, while the poorest pool was found in low-elevation spruce forests, beech forests and Scots pine ( Pinus sylvestris ) forests. High-elevation spruce forests also had the highest number of red-listed lichens, as the non-intensive management of these forest type allows the establishment of a rich lichen biota. Our results also emphasize the role for lichen conservation of some forest types that are of minor economic importance, such as oak ( Quercus pubescens ), riparian, and silver-fir ( Abies alba ) forests. This can also apply to grazed larch ( Larix decidua ) forests that are maintained by traditional farming, which shape one of the most pleasing aspects of the Italian Alpine landscapes. • Does forest type predict epiphytic lichen diversity in the Italian Alps? • We studied epiphytic lichen communities in the main forest types of the Italian Alps. • Significant differences in species composition and richness were found among forest types. • Conservation of lichen diversity is linked to the maintenance of forest landscape heterogeneity. • Forest with low-economic value highlighted also a key role on lichen conservation.

Topographic and forest-stand variables determining epiphytic lichen diversity in the primeval beech forest in the Ukrainian Carpathians

The Uholka-Shyrokyi Luh area of the Carpathian Biosphere Reserve is considered the largest and the most valuable primeval beech forest in Europe for biodiversity conservation. To study the impact of different topographic and forest-stand variables on epiphytic lichen diversity a total of 294 systematically distributed sampling plots were surveyed and 198 epiphytic lichen species recorded in this forest landscape, which has an uneven-aged structure. The obtained data were analysed using a non-metric multidimensional ordination and a generalized linear model. The epiphytic lichen species density at the plot level was mainly influenced by altitude and forest-stand variables. These variables are related to both the light availability i.e. canopy closure, and the habitat diversity, i.e. the developmental stage of the forest stands and the mean stem diameter. We found that lichen species density on plots with a relatively open canopy was significantly higher than on plots with a fairly loose or closed canopy structure. The late developmental stage of forest stands, which is characterized by a large number of old trees with rough and creviced bark, had a strong positive effect on lichen species density. In the Uholka-Shyrokyi Luh primeval forest the mean stem diameter of beech trees significantly correlated with lichen species density per plot. Similar trends in the species diversity of nationally red-listed lichens were revealed. Epiphytic lichens with a high conservation value nationally and internationally were found to be rather abundant in the Uholka-Shyrokyi Luh area, which shows its international importance for the conservation of forest-bound lichens.

Development of Secondary Woodland in Oak Wood Pastures Reduces the Richness of Rare Epiphytic Lichens

Wooded pastures with ancient trees were formerly abundant throughout Europe, but during the last century, grazing has largely been abandoned often resulting in dense forests. Ancient trees constitute habitat for many declining and threatened species, but the effects of secondary woodland on the biodiversity associated with these trees are largely unknown. We tested for difference in species richness, occurrence, and abundance of a set of nationally and regionally red-listed epiphytic lichens between ancient oaks located in secondary woodland and ancient oaks located in open conditions. We refined the test of the effect of secondary woodland by also including other explanatory variables. Species occurrence and abundance were modelled jointly using overdispersed zero-inflated Poisson models. The richness of the red-listed lichens on ancient oaks in secondary woodland was half of that compared with oaks growing in open conditions. The species-level analyses revealed that this was mainly the result of lower occupancy of two of the study species. The tree-level abundance of one species was also lower in secondary woodland. Potential explanations for this pattern are that the study lichens are adapted to desiccating conditions enhancing their population persistence by low competition or that open, windy conditions enhance their colonisation rate. This means that the development of secondary woodland is a threat to red-listed epiphytic lichens. We therefore suggest that woody vegetation is cleared and grazing resumed in abandoned oak pastures. Importantly, this will also benefit the vitality of the oaks.

Co-variation of lichens, bryophytes, saproxylic beetles and dead wood in Swedish boreal forests

In order to effectively identify and protect the most valuable forest areas for conservation, it is essential to understand species diversity patterns and the co-variation of different taxonomic groups. In this study we analysed the extent to which lichens, bryophytes and saproxylic beetles co-vary, their ability to represent each other in a reserve network (surrogate capacity), and their patterns of beta-diversity. We also tested the surrogate capacity of dead wood. A species and dead wood inventory was conducted in forest sites in a boreal forest region in central Sweden. Overall, the correlations in species richness between taxa were weak, but some were statistically significant, i.e. those between red-listed lichens and red-listed bryophytes. Beetles were weakly positively correlated with bryophytes, but never with lichens. None of the tested taxa provided a reliable surrogate for representing the other taxa. However, dead wood diversity did represent saproxylic beetles and bryophytes better than random selection and might therefore function as a conservation surrogate for those taxa. Beta-diversity differed significantly between the taxa; lichens had the lowest, while beetles had the highest. Altogether beetles showed low association with the other taxa but high beta-diversity, which implies that they may require specific conservation planning.

Multispecies and Multiscale Conservation Planning: Setting Quantitative Targets for Red‐Listed Lichens on Ancient Oaks

Species occurrence in a habitat patch depends on local habitat and the amount of that habitat in the wider landscape. We used predictions from empirical landscape studies to set quantitative conservation criteria and targets in a multispecies and multiscale conservation planning effort. We used regression analyses to compare species richness and occurrence of five red-listed lichens on 50 ancient oaks (Quercus robur; 120-140 cm in diameter) with the density of ancient oaks in circles of varying radius from each individual oak. Species richness and the occurrence of three of the five species were best explained by increasing density of oaks within 0.5 km; one species was best explained by the density of oaks within 2 km, and another was best predicted by the density of oaks within 5 km. The minimum numbers of ancient oaks required for "successful conservation" was defined as the number of oaks required to obtain a predicted local occurrence of 50% for all species included or a predicted local occurrence of 80% for all species included. These numbers of oaks were calculated for two relevant landscape scales (1 km(2) and 13 km(2)) that corresponded to various species responses, in such a way that calculations also accounted for local number of oaks. Ten and seven of the 50 ancient oaks surveyed were situated in landscapes that already fulfilled criteria for successful conservation when the 50% and 80% criteria, respectively, were used to define the level of successful conservation. For cost-efficient conservation, oak stands in the landscapes most suitable for successful conservation should be prioritized for conservation and management (e.g., grazing and planting of new oaks) at the expense of oak stands situated elsewhere.

Lichen diversity and red-listed lichen species relationships with tree species and diameter in wooded meadows

This study provides a unique large dataset of total epiphytic lichen diversity (fruticose, foliose and crustose species) and composition on 1,294 trees of 17 tree species in wooded meadows in Sweden and Estonia, the Baltic region. The inventory (25,380 observations and 246 lichen taxa) clearly illustrated that Ulmus minor, Quercus robur and Fraxinus excelsior contributed most significantly to epiphytic lichen richness and number of red-listed species. In Sweden, average single tree α richness was 22.2 on Ulmus (only in Sweden), 21.6 on Quercus (25.0 in Estonia) and 19.8 on Fraxinus (16.7 in Estonia), respectively. Ulmus hosted on average one red-listed species per tree, compared with 0.7 on Fraxinus (0.6 in Estonia), 0.4 on Quercus (0.7 in Estonia) and only 0.05 on Betula (same in Estonia). Lichen species composition and the average number of red-listed lichens were influenced by tree diameter on Fraxinus and Quercus, whilst no such pattern was evident on Ulmus. Randomized species accumulation curves of the dominating tree species illustrated that Fraxinus, Quercus and Ulmus supported α dominated lichen communities where individual trees hosted a substantial part of the total richness. Betula, on the other hand, supported β dominated communities where individual trees tended to be dissimilar and, therefore, more of the total richness existed as species turnover among host trees. Lichen species composition was influenced by tree species, and most notably, lichen species on Ulmus had a strong consistent clumping in ordination graphs, with many rare and red-listed lichens. The broadleaved deciduous trees within the wooded meadows clearly contribute greatly to the biodiversity of the Baltic region.

Generation time estimated to be 25–30 years in Cliostomum corrugatum (Ach.) Fr.

Lichens are an important group of organisms in terms of environmental issues, conservation biology and biodiversity, principally due to their sensitivity to changes in their environment. Therefore it is important that we develop our understanding of the factors that affect lichen distribution. In this thesis, both spatial and temporal distributions of epiphytic lichens at different scales have been studied in southern Sweden.Generation time of the red-listed lichen Cliostomum corrugatum was examined using Bjarka-Saby as the study site. The results showed that the average age of an individual of C. corrugatum is 25–30 years at the onset of spore production.The rarity of C. corrugatum was also examined. DNA analysis of an intron from 85 samples, collected at five sites in Ostergotland, yielded 11 haplotypes. Results from coalescent analysis, mantel test and AMOVA indicated that C. corrugatum have a high ability to disperse. The study concluded that its rarity is most likely connected with the low amount of available habitat, old Quercus robur.The changes in the distribution of epiphytic lichens in southern Sweden, between 1986 and 2003, were also compared. For each year a centroid was calculated on all combinations of tree and lichen species. The three significant cases showed that the centroid movement pointed toward a north-east or north-north-east direction.Finally differences in species richness and cover of lichens on large Q. robur were examined between urban and rural environment. The results demonstrated that species number and percent cover was significantly higher on oaks standing rural compared to oaks standing urban. Effects of urban sprawl showed a decline in species richness and cover with increasing age of the surrounding buildings.

Critical forest age thresholds for the diversity of lichens, molluscs and birds in beech (Fagus sylvatica L.) dominated forests

Forest age is one of the most simple but ecologically effective key values that may be controlled by forest management. Young and mature but managed forests differ significantly from old-growth forests in species composition, structure and socio-ecological function. Human land-use has already caused the loss or dramatic reduction in occurrence of some entire species assemblages, especially of logging-sensitive species, in Central European forests. These general statements also apply to beech forests, beech (Fagus sylvatica) being the naturally dominating tree species in Central Europe. Based on data for breeding birds (from 258 sampling plots in a sub-montane and 228 plots in a montane area), molluscs (36 plots in the sub-montane and 79 plots in the montane area) and lichens (84 plots in the montane forest), this paper aims at identifying significant forest age threshold ranges for the occurrence of these old-growth sensitive taxa. The sampling plots in the sub-montane zone (420–520 m a.s.l.) are in beech-oak forests, plots in the montane zone (650–1150 m a.s.l.) are in beech-spruce-fir forests. Stand ages in both areas range up to around 350–400 years. Threshold values for the total number of species related to stand age were calculated by recursive partitioning. In all three taxonomic groups the number of species per plot significantly increases with forest age. The same analysis was run for red-listed lichen and mollusc species as well as hole-nesting bird species. The threshold values obtained are very similar to those for the whole species assemblages, except for molluscs where considerably lower threshold values are computed with red-listed species assemblages. Regarding the confidence intervals, the difference pattern between the whole species datasets and the more sensitive species subsets is inconsistent. Threshold values in sub-montane beech forests range from 100 to 170 years and in mixed montane forests from 160 to 220 years. These threshold levels are clearly incompatible with economic interests that aim on reducing the rotation period in beech stands to less than 140 years to avoid formation of red heartwood. It would therefore seem to be essential to establish a network of trees and stands that are never logged and may thus act as areas for retreat and dispersion for logging-sensitive species.

Vertical distribution of epiphytic bryophytes and lichens emphasizes the importance of old beeches in conservation

During storms in 2005, a number of beech trees fell over at Biskopstorp, SW Sweden, offering the opportunity to study epiphytes along entire stems. In total 16 beech trees in four beech stands representing three different age classes were included. For each tree, 2 m segments from the base to the top were surveyed. In total 115 species were found (76 lichens, 39 bryophytes), of which 30 were considered to be of conservation concern (22 lichens, 8 bryophytes). For lichens significantly more species were recorded above 2 m in height, whereas more bryophytes were recorded below 2 m in height. Certain red-listed lichens were recorded only above 2 m in height on old trees. In a second data set from the same area 140 age-determined beech trees were surveyed for species of conservation concern at the heights 0–2 and 2–5 m, respectively. These species were found almost exclusively on old beech trees, and presence at 2–5 m was recorded, with one exception, only on those trees which also had species of conservation concern at 0–2 m. Records of these species correlated significantly to microhabitat variables, i.e. the presence of rough bark and moss cover higher up the stems on the old trees. This study indicates that surveying only the base in really old beech forests can underestimate both the number of species of conservation concern and their population sizes. However, surveys restricted to the base in rather even-aged beech stands catch a large proportion of the trees with species of conservation concern.

Large-scale occurrence patterns of red-listed lichens and fungi on old oaks are influenced both by current and historical habitat density

Current occurrence patterns of species associated with ancient trees may reflect higher historical habitat densities, because the dynamics of the habitat and the colonisation-extinction processes for many inhabiting species are expected to be slow. We tested this hypothesis in southeast Sweden by analysing species occurrence per parish for twelve redlisted lichen species and nine redlisted fungus species in relation with current density of big oaks, the density of oaks in the 1830s and connectivity with parishes with the species present. For most species, the occurrence was positively related with current density of habitat (for 18 species out of 21) and parish area (for 16 species). Historical habitat density was positively related with occurrence for 11 species, while connectivity with current occurrences in the surroundings was positive for the occurrence of 12 species and negative for the occurrence of two. For lichen species the connectivity measure that best explained the variation was at a larger spatial scale as compared to fungus species. Even if the density of old oaks remains in the future, inhabiting species will most likely decline because their distribution patterns are not in equilibrium with the current habitat density. Therefore, to allow long-term persistence of inhabiting species the number of old oaks should be increased. Areas where such an increase is most urgent could be identified based on species occurrence data and current habitat density, but because species data will always be incomplete data on the historical habitat distribution is valuable.

Importance of Forest Act habitats for epiphytic lichens in Finnish managed forests

Habitats of particular importance, as defined in the recent Forest Act of Finland, provide a new means to conserve forest biodiversity in managed forest landscapes. These “Forest Act habitats” should by definition contain populations of rare and red-listed species, but their species composition has not been studied. In this work, indicator and red-listed lichens were studied in private forests of southern Finland in three Forest Act habitat types (brookside forests, herb-rich forests, cliff-forests). Threatened species were found only in 9%, red-listed species in 29% and indicator species in 50% of the study sites. Populations of the target species were mainly very small, half of them on no more than one tree, and thus prone to extinction. Picea abies, Populus tremula and Sorbus aucuparia were the most important host tree species for indicator lichens. The Forest Act habitats appear to make only a limited contribution to the conservation of indicator and red-listed lichens. This is because delimited Forest Act habitats are small-sized sites and rarely harbour old forest stands. Moreover, even selective logging and felling of individual trees, which are generally permitted in Forest Act habitats, can decrease the persistence of epiphytic lichens. Thus, the biodiversity goals integrated in the Forest Act appear to be incompletely realized in current forestry practices.

Red-listed and indicator lichens in woodland key habitats and production forests in Sweden

There are ca. 70 000 "woodland key habitats" (WKHs) in Sweden that according to definition should contain red-listed species, but their species content is seldom known. Indicator species are used as one tool to identify the WKHs. In two areas in southern Sweden red-listed and indicator lichen species were surveyed in line transects in a total of 25 WKHs (45 ha) and, for comparison, in 74 ha of surrounding production forest. Altogether 19 red-listed species, representing ca. 25% of the Swedish Red List forest lichen species so far recorded from the study areas, and 35 indicator species were found. Ninety-five percent of all records were epiphytic. The most evident result from this study was the large difference in the number of species records in the production forests between the two study areas. In contrast, the WKHs in both areas had a similar number of species records. The WKHs were expected to be significantly richer than the production forests in regard to the occurrence of indicator and red-listed species, but this was only found to be true in one of the areas. In both areas there was a tendency for the rarest red-listed species to be confined to the WKHs. Nestedness and correlation analyses suggested that Arthonia vinosa was a relevant indicator of red-listed lichens; however, Calicium parvum was found to be inappropriate as an indicator species. It is concluded that at the regional scale the production forest can host considerable amounts of indicator and red-listed lichen species but that the WKHs are important for the preservation of rare lichens.