D ata sampling of rare and common species for compiling a Red List of epiphytic lichens
Michael D ietrich, Silvia Stofer, Christoph Scheidegger, Martin Frei, U rs G roner, Christine Keller, Irene R oth and Charlotte Steinmeier
WSL Swiss Federal R esearch Institute, Z ürcherstrasse 111, CH -8903 Birmensdorf, Switzerland m.dietrich@bluewin.ch; silvia.stofer@wsl.ch; christoph.scheidegger@wsl.ch; martin.frei@wsl.ch;
urs.groner@wsl.ch; christine.keller@wsl.ch; Irene.R oth@bfs.admin.ch; charlotte.steinmeier@wsl.ch
A bstract
The revised IU CN R ed List categories (1994) focus on any past and future reduction and on the current distribution and frequency of the taxa.The criteria and sub-criteria to categorize organisms are fully quantitative and require corresponding data. In order to apply these criteria appropriate- ly for the establishment of the R ed List of Switzerland’s epiphytic lichens, an intensive inventory was made from 1995 to 1999. Lichen data were recorded in three different surveys:A representative survey, based on a stratified random sample of 826 permanent observation plots, guaranteed the comparability between the different taxa; the mapping in squares of 400 km2gathered as much information as possible on the rarer species; the third survey included all other floristic lichen data.
A total of 656 lichen taxa was recorded. Based on the representative data, many inconspicuous species turned out to be common. The conservation categories based on current distribution and frequency have been determined by estimating the extent of occurrence, the area of occupancy and the number of locations according to IU CN criterion B. 38% of the epiphytic lichens would be given the status of “threatened” if based on current distribution and frequency alone. For the final R ed List the taxa will be tested against all applicable IU CN criteria and sub-criteria.
Keywords: lichenized fungi, epiphytes, R ed List, Switzerland, conservation biology, inventory, permanent plots, IU CN
1 Introduction
The conservation of biological diversity is a major challenge to land management.A n import- ant tool for setting priorities in conservation strategies are R ed Lists of species or habitats.
R ed Lists of species estimate the current degree of threat of organisms at the global or any regional level.Therefore, consistency and objectivity in assessing extinction risks are important requirements for a successful handling of R ed Lists in the practice of nature conservation.A s a consequence, IU CN (1994) redefined the R ed List categories and developed a system of criteria (numbered from A to E ) and sub-criteria to evaluate extinction risks.
In Switzerland an official R ed List has been published for bryophytes (UR MI1993). O ther R ed Lists of cryptogams are only preliminary, like the list of macrolichens (CLE R Cet al. 1992) and the list of macrofungi (SE NN-IR LE Tet al. 1997). None of them referred to the quantitative criteria of IU CN (1994). For the official R ed List of Switzerland’s epiphytic lichens, a formal adaptation to IU CN criteria is planned. A s in other R ed Lists of lichens (e.g. CH U R CHet al.
1997 [1996], WIRTHet al. 1996), some criteria or sub-criteria may not be directly applicable, e.g. due to the symbiotic way of life and the unclear delimitation of individuals (FA H SE LT
1996). More difficulties arise because many species are rather inconspicuous, and because relatively few historical data on lichen distribution and frequency are available.
A set of parameters, which can also be assessed for inconspicuous sedentary, often clonal organisms, includes the extent of occurrence, the area of occupancy and the number of locations (IU CN criterion B). R easonable estimates of these measures are best provided by an inventory. Therefore, on the one hand, the sampling of representative data for all species is of key importance (DIE TR ICHand SCH E ID E G G E R1997a). O n the other hand, a maximum of information is necessary for adequate and effective conservation strategies for the rarer and locally restricted taxa.
R epresentative data collection was carried out earlier in the Swiss Forest Inventory (E A FV and BFL 1988, BR A SSE Land BR Ä ND LI1999) on a large sample of long term observation plots, determined by the kilometer grid of the national coordinate system. The official R ed List of bryophytes (UR MI1993) combined different field sampling methods proposed by UR MIet al.
(1990): R epresentative data are guaranteed by a random sample of observation plots, systematically distributed over Switzerland; additionally, different habitats had to be sampled to detect rare and ecologically restricted species.
A n intensive inventory of the epiphytic lichens was undertaken from 1995 to 1999. The main objective of the inventory was to support the determination of the R ed List status of the species according to IU CN criteria. The representative survey of all lichen species, thereby, aimed to estimate the area of occupancy of the species, based on their sampled frequency.The intensive mapping in 20 x 20 km2, with special reference to rare and potentially threatened taxa, in addition to all the other floristic lichen data, was designed to calculate both the extent of occurrence and the number of locations.
2 Methods
2.1 Stratified random sample of small permanent plots
Floristic standard sampling was carried out on long-term ecological observation plots located on the intersection points of the 1 x 1 km grid of the Swiss coordinate system.
Pre-stratification was performed according to region, vegetation formation and vegetation belt (Table 1).The strata of every intersection point were given by the Swiss Forest Inventory (E A FV and BFL 1988, BR A SSE Land BR Ä ND LI1999).
Table 1. The strata and the percentage area of Switzerland (T = 41291 km2) they cover.
Level of stratification Strata %
R egion Jura 11.9
Central Plateau 22.8
Pre-A lps 16.0
A lps 40.7
Southern A lps 8.6
Vegetation formation Forest 28.7
Non-forest 71.3
Vegetation belt Colline-submontane 31.9
Lower montane 14.9
U pper montane 12.9
Lower subalpine 12.7
U pper subalpine 9.0
A lpine/nival 18.6
A random sample of 826 plots was investigated, representing 2% of Switzerland’s 1-kilo- meter intersection points (Fig. 1). Within the strata, the plots were allocated proportionately to their total surface. Moreover, they were selected at random, and no special attention was paid to habitats potentially rich in epiphytic lichens. A ccording to the national map of Switzerland (1:25 000), the intersection points falling on lakes, big rivers or glaciers were excluded from field sampling as well as those located above 2500 meters a.s.l., where we do not expect any trees, shrubs or dwarf shrubs.
Plot definition follows the Swiss Forest Inventory (E A FV and BFL 1988; ZING G1988). O n every long term observation plot of 500 m2, divided into an inner (r = 7.98 m) and an outer area (r = 12.62 m), all trees, shrubs and dwarf shrubs present were investigated to record all epiphytic lichen taxa (presence/absence):
First, we recorded the lichen data per tree species. We started on the inner circular area on individual trees with a dbh >12 cm, from the base of the trunk up to a stem height of 170 cm.
E very tree was unambiguously identified. We continued recording additional lichen species on individuals with a dbh >12 cm in the outer circle. In the next step we sampled lichens on individual trees of the entire plot surface with a dbh <12 cm. A ll parts of the trees other than the trunk from 0–170 cm were subsequently investigated. Finally, all lichen species not observed before were recorded for the shrub layer and then for the dwarf shrub layer.
E cological plot data like the structure of the tree layer, the habitat, and the relief were always recorded. Field sampling was carried out by one professional lichenologist and took three hours on average.
2.2 Mapping in squares of 400 km
2This survey is based on a 20 x 20 km grid dividing Switzerland into mapping units of 400 km2 surface. 56 squares were selected, whereas squares with relatively few published lichen data had higher priority. They represent about 50% of Switzerland’s total surface (Fig. 2).
In every square the aim was to register as many taxa as possible; the time spent in a square was four to six days, depending on its altitudinal range.To compensate for personal preferences and knowledge, every mapping unit was visited by more than one professional lichenologist subsequently.
Fig. 1.The 826 observation plots of the representative survey in the five main regions of Switzerland: Jura
= 98; Central Plateau = 189; Pre-A lps = 132; A lps = 336; Southern A lps = 71.
Jura
Central Plateau Pre-A lps A lps Southern A lps
A ll lichen taxa were recorded at the level of individual trees, shrubs and dwarf shrubs. The records were characterized by the coordinates, the substrate (plant species), the bark struc- ture, the diameter at breast hight (dbh), the location on the host plant, and the ecological data mentioned above.
2.3 Other floristic lichen data
Floristic lichen data from 1989 onwards were collected all over Switzerland. Published and unpublished data, including public and private herbaria, were registered, as well as the results of the floristic activities of the Swiss A ssociation of Bryology and Lichenology (SVBL).
Furthermore, voluntary collaborators worked in some of the mapping units not sampled by professionals (Fig. 2).
2.4 Lichen identification
D ata sampling was carried out from 1995 until 1999. Taxa were identified in the field or, if a reliable identification was not possible, specimens were collected for analysis in the labora- tory. Standard examination included dissecting and light microscopy, and chemical analysis where necessary (TLC according to CU LBE R SO Nand AMMA NN1979 and CU LBE R SO Nand JO H NSO N1982). A bout 9000 chemical analyses were carried out during the project.
A ll species records of each survey were marked “observation”, “herbarium specimen, determination certain” or “herbarium specimen, determination uncertain”. The nomencla- ture in general follows WIRTH(1995).A ll lichen specimens from the random plots, and the 56 mapping squares are deposited at the herbarium of G eneva (G ). A t the time 95% of the records from the random plots, and 80% of all other data were entered into the relational database LICH E N.
Fig. 2. The 20 km x 20 km (400 km2) grid covering Switzerland. The 56 intensively mapped squares are hatched.
2.5 D ata analysis
The R ed List status of a taxon was assigned according to IU CN criterion B (1994) as follows:
E xtent of occurrence estimated to be less than xkm2, or area of occupancy estimated to be less than ykm2, and the taxon estimated to exist at no more than zlocations.
The extent of occurrence is defined as the surface in km2within the shortest polygon enclosing all currently known localities of a taxon in Switzerland. The points of occurrence were transferred into a geographic information system (G IS), enabling the calculation of the surfaces. The area of occupancyis the area within a taxon’s extent of occurrence which is really occupied by the taxon. It was estimated on the basis of the number of observation plots in the representative survey. E ach plot where a particular lichen was observed represents an area of occupancy of 50 km2. Finally, a locationis a geographically or ecologically distinct area where a single event will possibly affect all the individuals of a taxon. For the epiphytic lichens of Switzerland, we have assumed that a location has a one km2surface.Thus, all recorded data were plotted on a 1 x 1 km grid and the number of squares (1 km2) was counted for every taxon.
3 Results
656 different lichen taxa growing as epiphytes have been registered for Switzerland since 1989.
This number includes 629 species, 5 subspecies, 13 varieties, 2 forma and 7 aggregates of lichen species. Several distinct taxa, all of the crustose growth, form could not be identified.
R egional lichen diversity is highest in the A lps (531 taxa) and lowest in the Southern A lps (321; Table 2).
Table 2. O bserved lichen diversity for Switzerland and the 5 regions, as well as capture of taxa by the representative survey.
capture of the mean number highest plots with total number representative per plot with number woody plants number
of taxa survey (% ) woody plants on one plot (% ) of plots
Switzerland 656 66 24.3 ± 15.5 75 53 826
Jura 377 65 25.8 ± 15.1 71 62 98
Central Plateau 361 55 17.6 ± 10.9 55 52 189
Pre-A lps 466 61 26.2 ± 13.0 63 65 132
A lps 531 67 27.9 ± 18.0 75 44 336
Southern A lps 321 65 21.8 ± 15.9 56 65 71
386 of the 826 randomly selected observation plots turned out to be without any trees,shrubs or dwarf shrubs. In the Southern A lps 65% of the plots had woody plants, but in the A lps only 44% . O n the 440 observation plots with trees, shrubs or dwarf shrubs, 24.3 lichen taxa were observed on average (Table 2). The Central Plateau shows distinctly the lowest value of observed taxa per plot (17.6). In the A lps, the Pre-A lps and the Jura more than 25 taxa were found per observation plot.The highest species number (75) was recorded on a plot in the A lps.
With the representative survey 434 (66% ) of the 656 taxa were registered. Most of the taxa were found on a few plots only. 92 taxa (14% ) were observed on one plot, 44 (7% ) on two and 31 (5% ) on three plots (Fig. 3 A ). In contrast, only 125 lichen species (19% ) were registered on more than 20 plots, including many small and inconspicuous crustose species: e.g.
A nisom eridium polypori (E llis & E verhart) M.E .Barr (35 plots),A rthonia didym a (49),
A rthonia spadicea(37),B uellia griseovirens(155),G yalideopsis anastom osans(22),L ecidella sp. 1 (63),L .sp. 2 (44) (DIE TR ICHand SCH E ID E G G E R1996a),Protoparm elia hypotrem ellavan H erk, Spier & Wirth (23) and Schism atom m a pericleum(25).
The 10 most frequent species were H ypogym nia physodes(195 plots),Parm elia glabratula (192),M icarea prasina(189),Phlyctis argena(187),Parm elia sulcata(182),L epraria lobificans (173), D im erella pineti(170),L ecidella elaeochrom a s.l. (164),Pseudevernia furfuraceas.l.
(163) and L epraria rigidula(159).
623 (95% ) of the 656 taxa were recorded within the fifty-six 20 x 20 km2. The highest diversity of epiphytic lichens observed in a single square was 300.
Lichen frequencies in these squares were found to be low, as they are in the representative survey (Fig. 3 B): 109 taxa (17% ) in one mapping unit, 57 (9% ) in two and 40 (6% ) in three.
O nly 191 taxa (29% ) were observed in more than 20 squares. They included the potentially rare species L eptogium saturninum present in 38 squares,L obaria pulm onaria in 26 and M enegaz z ia terebratain 24. 23 taxa (4% ) were identified in more than 50 squares;L ecidella elaeochrom a s.l. and Parm elia sulcata occurred in all the squares, and A rthonia radiata, H ypogym nia physodesandPseudevernia furfuraceas.l. in 55 squares.
Within the other 20 x 20 km2, 508 taxa (77% ) were registered. The highest species number in a square was 233.
112 taxa (17% ) appeared in one mapping unit only (Fig. 3 C). 56 taxa (9% ) were registered in more than 20 squares. The species occuring in the highest number of squares were H ypogym nia physodesin 52 and Parm elia glabratulaand P. sulcataeach in 51 squares.
b
Percentage of taxa
a
Number of observation plots
c
Percentage of taxa Percentage of taxa
0 50 100 150 200
Number of squares
0 10 20 30 40 50
Number of squares
0 10 20 30 40 50
0 4 8 12 16 20 24 28 32
0 2 4 6 8 10 12 14 16
0 3 6 9 12 15 18 21 24
Fig. 3. Frequency distribution of all lichen taxa based on the plots of the representative survey (a), the intensively mapped 20 km x 20 km squares (b), and the rest of 20 km x 20 km squares (c).
3.1 The combined data of current distribution and frequency in relation to the IU CN Red List criterion B
O f the 656 taxa observed on trees, shrubs or dwarf shrubs, in Switzerland 99 (15% ) grow preferably on other substrates, e.g.Cystocoleus ebeneusandR hiz ocarpon geographicum on stone,Cetraria islandicaand Cladonia incrassataon ground or T helom m a occelatum and X ylographa paralellaon wood.
394 taxa (60% ) predominately live as epiphytes, and 163 lichens (25% ) are less substrate specific. A ll these 557 taxa will be considered for the compilation of the official R ed List of epiphytic lichens of Switzerland. Their extent of occurrence, area of occupancy and number of locations are summarized in Table 3.
73 lichens (13% ) of the 557 show an extent of occurrencegreater than the total surface of Switzerland. The calculation of the extent of occurrence was not possible for the 87 taxa with less than 3 records, e.g.G raphis elegansand Sticta lim bata. Their surfaces were assumed to be smaller than 1 km2. O nly 18% of the taxa would hypothetically be classed as critically endangered,based on the minimum value for this category. 46% would not be threatened.
30% of the lichens seem to be critically endangered, and 13% not threatened if classed only according to the area of occupancy. For all the 167 lichens with no record on a random plot, such as the above mentioned G raphis elegansand Sticta lim bata, the area of occupancy was assumed to be smaller than 10 km2.
62% of the lichens would not be classed for any category of threat if based on the num ber of locationsonly. They are currently known from more than 10 locations. The highest number of locations is 701 for Parm elia sulcata. 11% of the taxa were observed in one location only and thus would hypothetically qualify for classification as critically endangered.
With an extent of occurrence smaller than 100 km2 or an area of occupancy smaller than 10 km2, 33% of the lichens would be given the status of critically endangered. O nly 13% would then not be threatened. Combining the three different measures of current distribution and frequency in the defined sense, 11% of the lichens appear to be critically endangered, 16%
endangered and 11% vulnerable. A high percentage of the lichen taxa (62% ) would not be considered threatened according to IU CN definitions if based on IU CN criterion B alone.
Table 3. Percentages of taxa (n=557) qualifying for the conservation categories hypothetically based on each measure of IU CN criterion B and on the combined measures.
Critically
E ndangered E ndangered Vulnerable Not threatened a) extent of occurence (km2) <100 18% <5000 11% <20000 25% >20000 46%
b) area of occupancy (km2) <10 30% <500 36% <2000 21% >2000 13%
c) number of locations 1 11% <5 16% <10 11% >10 62%
a) or b) 33% 32% 22% 13%
a) or b) and c) 11% 16% 11% 62%
4 D iscussion
O ur knowledge of the current distribution and frequency of epiphytic lichens in Switzerland has been restricted so far to some well studied species. For many lichens it has been biased by studies of defined habitats or areas (e.g. CA ME NZ INDand WILD I1991, DIE TR ICH1991, FR E I
and GR ATZ FE LD1991, GRO NE R1990, ROTHand SCH E ID E G G E R1997, SCH E ID E G G E Ret al.
1995, RU O SS1992, SCH E ID E G G E Ret al. 1991, VO NA R BU R G1995).
A n intensive field survey of the current lichen flora was required in order to create a national R ed List. In addition, the evaluation of the historical distribution of the lichens made intensive literature and herbaria studies necessary (CLE R Cet al. 1996). Possible errors orig- inating from previous drastic changes in the lichen flora, e.g. caused by pollution and forest management as mentioned by JACO BSE Net al. (1992), are reduced by setting the lower limit of “current” to 1989.
Inventories of most organisms are based on mapping units such as squares of defined size, like the 10 x 10 km2of the Flora of the British Isles, including lichens (SE AWA R Dand HITCH
1982), or the squares of 10 minutes longitude and 6 minutes latitude of the lichens of Baden- Württemberg (WIRTH 1987). D ata collection in topographically diverse countries like Switzerland may be based on ecologically homogeneous mapping units as proposed by WE LTE N(1971) for the atlas of vascular plants (WE LTE Nand SU TTE R1982). In this case it is difficult to guarantee that the frequency and distribution will be representative, if the units and the taxa are not mapped with the same intensity.
The stratified random sample, where no special attention was given to potentially rich habitats, aimed at recording lichen frequencies representative for Switzerland and its five regions (DIE TR ICH and SCH E ID E G G E R 1997a). It was designed as a long-term ecological observation, so it may be repeated in the future. In addition to the representative frequency data, monitoring of lichen diversity and distribution will be possible (DIE TR ICH and SCH E ID E G G E R 1997b), as well as the quantification of derived parameters of ecological changes (DIE TR ICHand SCH E ID E G G E R1996b).
The results from this survey allowed to compare frequencies in terms of number of observation plots for all taxa.Thereby a lot of small and inconspicuous species which had been neglected so far, turned out to be common. O bviously, the sorediate crustose lichens are, as mentioned in DIE TR ICHand SCH E ID E G G E R(1996a), an important part of the most common species. In contrast, several well known fertile crustose species were not recorded with the representative study, which illustrates the rarity of e.g.Cyphelium lucidum,G raphis elegans or L ecanora cinereofusca.
A lpine plots with trees, shrubs or dwarf shrubs are rather scarce (44% ) in the stratified random sample due to the fact that most of them belong to the alpine/nival vegetation belt.
Nevertheless, 67% of the total lichen flora recorded in the A lps were observed on the obser- vation plots. In contrast only 55% were registered in the Central Plateau, where 52% of the plots had woody plants.The low overall diversity and the low mean lichen species number per plot are mainly the result of intensive land management in forests and non-forests.
Furthermore, total species numbers are certainly affected by the different total surface areas and the different altitudinal ranges of the regions (DIE TR ICH and SCH E ID E G G E R 1997b, WO H LG E MU TH1993). The maximum species number of 55 on a 500 m2plot shows that even on the Central Plateau, where past and present human impact is highest, sites with considerable lichen diversity still exist.
In general, taxa with high frequencies on observation plots showed high frequencies on the 20 x 20 km2. Nevertheless, in comparison with those of the common species the frequencies of the rarer taxa would be overestimated if they were only based on the 400 km2squares. The 92
taxa found on one plot only were recorded in 4.3 (on average) of the 56 intensively mapped 400 km2squares and in 1.6 of the less intensively mapped squares. Compared to the represen- tative frequency this corresponds to an overestimation of more than 15 and 5, respectively (Fig. 4). The 5 taxa found on 15 plots were still recorded more than 5 times more frequently with the intensive mapping (22 squares) and more than twice as frequently when based on the other squares (9). UR MIet al. (1990) demonstrated a corresponding underestimation of the frequency of common species based on traditional mapping represented by herbarium specimens.
The special attention paid to the rarer species within the 56 mapping squares revealed numerous additional localities for some well known,potentially threatened taxa.Nevertheless, no additional localities were found for several macrolichens classified as critically endangered in the preliminary R ed List of Switzerland (CLE R C et al. 1992), such as H eteroderm ia obscurata, L obaria am plissim a,Parm elia reticulataand Usnea florida.
4.1 The IU CN Red List criterion B
HO D G E TTS(this volume) proposes using IU CN criteria of extinction risks A to E (1994) with specific adaptations, appropriate for cryptogams. In addition to the measures discussed in his paper, in the R ed List of the epiphytic lichens of Switzerland special attention will be paid to the use of “mature individuals” and to the “probability of extinction” (SCH E ID E G G E Ret al.
this volume). Nevertheless, criteria or sub-criteria, which are not applicable will remain as mentioned. In future, the announced general changes and recommendations (IU CN 1999a), and the guidelines for application at national and regional levels (IUCN 1999b) will essentially help to improve R ed Lists.
0 2 4 6 8 10 12 14 16
0 20 40 60 80 100
R elative frequency based on the representative survey
Frequency relative to the representative survey
R epresentative survey Intensively mapped squares R est of the squares
Fig. 4. R elative frequencies based on the intensively mapped 20 km x 20 km squares and the rest of the squares in relation to the representative data.
The data recorded is presented according to the IU CN criterion B. U sing the extent of occurrence, the area of occupancy and the number of locations means the focus is clearly on the current distribution and frequency. A s little information is available on the dynamics of lichens (CH U R CHet al. 1997 [1996]), the sub-criterion of extreme fluctuations was not applied.
In addition, we omitted speculations about any continuing decline of the taxa. Thus, criterion B here is completely based on the current situation of the lichens. Because only epiphytic sub- strates were included in the survey, the 99 taxa recorded that predominately growing on rock, soil or wood were not tested against criterion B.Their data will be valuable for corresponding R ed Lists, e.g. of terricolous lichens (VU STand CLE R C1998). A s a consequence for the taxa treated within the epiphytes, observations from other substrates will be considered.
D ue to the relatively small surface area of Switzerland (41 291 km2) the threshold of the extent of occurrence for vulnerable (<20 000 km2) is almost equal to half of the country.
Nevertheless, 46% of all epiphytic taxa have an extent exceeding this value. D iscontinuities and disjunctions within the overall distribution (e.g. due to the alpine/nival vegetation belt) were not excluded.
The threshold of the area of occupancy to qualify for vulnerable (<2000 km2) almost corresponds to 5% of Switzerland. It was not exceeded by 87% of the taxa. Because the calculated values are based on the representative data, they are thought to be a good approxi- mation to the current area of occupancy. Concerning the thresholds specific adaptations have to be made for different groups of organisms (IU CN 1999a).
In addition to a restricted extent of occurrence or a small area of occupancy, any status of threat of a taxon requires, in accordance with the definition, a low number of known locations.
This measure (threshold >10) is responsible for the high percentage of taxa (62% ) which could not be classified based on current data alone. Nevertheless, the proposed size of 1 km2for a location is thought to be reasonable for the epiphytic lichens of Switzerland. A n increase in size would increase the number of threatened taxa.
Because not all the data have yet been entered into the database, the percentages of taxa within the different conservation categories are provisional. 38% of the current epiphytic lichen flora would be classified as threatened. Species which have been indicated as extinct in the preliminary R ed List of macrolichens of Switzerland (CLERCet al. 1992) and not recorded with the survey, such as H eteroderm ia leucom elosor Teloschistes chrysophthalm us, have not been considered yet.
For the final version of the R ed List of the epiphytic lichens, all the taxa will be tested against all applicable IU CN criteria.
A cknowledgements
We are grateful to the Swiss Federal O ffice of E nvironment, Forests and Landscape (BU WA L) for financial support (WSL Project No. 6.94.900) and to S. Lussi and E . Kohli for their ongoing interest and support of the project. O ur sincerest thanks go to P. Clerc (G enf), B.J. Coppins (E dinburgh), H . Mayrhofer (G raz), T. Tønsberg (Bergen) and O. Vitikainen (H elsinki) for the workshops they held in Switzerland.We also gratefully acknowledge their help in determining numerous specimens, together with that of P.M. Jørgensen (Bergen), R . Moberg (U ppsala), C. Printzen (Köln), E . Sérusiaux (Liège), U. Søchting (Kopenhagen), L. Tibell (U ppsala) and E . Timdal (O slo). We would also like to thank P. Brassel and A . Schwyzer, (Birmensdorf) for the plot data and N. Baumberger, M. H ägeli, P. Jakob, F. Sutter and H .Wey (Birmensdorf) for the support of the data base.The authors would especially like to thank the voluntary co-workers H . H ilfiker (Frauenfeld) and E . Z immermann (Bibern) for providing many lichen data.We are grateful to P. Clerc (G enf), E . R uoss (Luzern), C. Vonarburg (Z ürich), AG B and puls (Bern) for placing their lichen data at our dispos- al, and the members of SVBL for collecting specimens during field meetings of the association.
5 References
BR A SSE L, P; BR Ä ND LI, U.-B. (eds) 1999: Schweizerisches Landesforstinventar. E rgebnisse der Zweitaufnahme 1993–1995. Birmensdorf, Eidg. Forschungsanstalt WSL. Bern, Bundesamt für U mwelt Wald und Landschaft. Bern, Stuttgart, Wien, H aupt. 442 pp.
CA ME NZ IND, R .; WILD I, E ., 1991: D ie epiphytische Flechtenflora des G urnigel-G antrischgebietes (BE ). Bot. H elv. 101: 183–197.
CH U R CH, J.M.; CO PPINS, B.J.; GILBE RT, O.L.; JA ME S, P.W.; STE WA RT, N.F., 1997 [1996]: R ed D ata Books of Britain and Ireland: Lichens. Volume 1: Britain. Peterborough, Joint Nature Conservancy Committee. 84 pp.
CLE R C, P.; SCH E ID E G G E R, C.; AMMA NN, K., 1992: Liste rouge des macrolichens de la Suisse. Bot.
H elv. 102: 71–83.
CLE R C, P.; FIO R E, A .-M.; BO U VIE R, C.; DIE TR ICH, M.; FR E I, M.; GRO NE R, U.; KE LLE R, C.; ROTH, I.; STO FE R, S.; SCH E ID E G G E R, C.; WILD I, E ., 1996: Mapping of Swiss Lichens: Past and present distribution of selected species. In: TÜ R K, R .; ZO R R E R, R . (eds) Progress and Problems in Lichenology in the Nineties – IA L 3. A bstracts. p. 220.
CU LBE R SO N, C.F.; AMMA NN, K., 1979: Standardmethode zur D ünnschichtchromatographie von Flechtensubstanzen. H erzogia 5: 1–24.
CU LBE R SO N, C.F.; JO H NSO N, A ., 1982: Substitution of methyl tert.-butyl ether for diethyl ether in the standardized thin-layer chromatographic mehtod for lichen products. J. Chromatogr. 46:
85–93.
DIE TR ICH, M., 1991: D ie Flechtenflora des Merliwaldes, G iswil/OW (Z entralschweiz). Bot. H elv.
101: 167–182.
DIE TR ICH, M.; SCH E ID E G G E R, C., 1996a: The importance of sorediate crustose lichens in the epiphytic lichen flora of the Swiss Plateau and the Pre-A lps. Lichenologist 28: 245–256.
DIE TR ICH, M.; SCH E ID E G G E R, C., 1996b: D iversität und Z eigerwerte von epiphytischen Flechten der häufigsten Baumarten: E in methodischer A nsatz zur Beurteilung von U mweltverände- rungen im Wald und im Freiland. Bot. H elv. 106: 85–102.
DIE TR ICH, M.; SCH E ID E G G E R, C., 1997a:A representative survey of frequency of epiphytic lichens at the regional and national levels and its use for the red list of Switzerland. In: TÜ R K, R .;
ZO R R E R, R . (eds) Progress and Problems in Lichenology in the Nineties – IA L 3. Bibl. Lichenol.
68: 145–154.
DIETRICH, M.; SCHEIDEGGER, C., 1997b: Frequency, diversity and ecological strategies of epiphytic lichens in the Swiss Central Plateau and the Pre-A lps. Lichenologist 29: 237–258.
E A FV (E idgenössische A nstalt für das forstliche Versuchswesen);BFL (Bundesamt für Forstwesen und Landschaftsschutz) (eds) 1988: Schweizerisches Landesforstinventar: E rgebnisse der E rstaufnahmen 1982–1986. Ber. E idgenöss. Forsch.anst. WSL 305: 1–375.
FA H SE LT, D., 1996: Individuals, populations and population ecology. In: Nash, III, T.H . (ed) Lichen Biology. Cambridge, Cambridge U niversity Press. 181–198.
FR E I, M.; GR ATZ FE LD, J., 1991: E piphytische Moos- und Flechtengesellschaften – Versuch einer paralellen Betrachtung mit der Vegetation höherer Pflanzen. Bern, Syst.-G eobot. Institut der U niversität Bern. 173 pp.
GRO NE R, U., 1990: D ie epiphytischen Makroflechten im Bödmerenwaldgebiet, Muotatal SZ . Ber.
Schwyzerische Nat.forsch. G es. 9: 77–93.
IU CN, 1994: IU CN R ed List Categories. Prepared by IU CN Species Survival Commission. G land, IU CN. 21 pp.
IU CN, 1999a: IU CN R ed List criteria review provisional report. D raft of the proposed changes and recommendations. http://www.iucn.org/themes/ssc/provisional.htm.
IU CN, 1999b: D raft guidelines for the application of IU CN R ed List criteria at national and regional levels. http://www.iucn.org/themes/ssc/guidelines.htm.
JACO BSE N, P.; SCH O LZ, P.; JO H N,V.;WIRTH,V., 1992: Bearbeitungsstand und methodische Probleme bei der E rstellung von R oten Listen gefährdeter Flechten. Schr.reihe Veg.kd. 23: 113–121.
ROTH, I.; SCH E ID E G G E R, C., 1997: D ie E delkastanie als Lebensraum für epiphytische Flechten.
Bündnerwald 50, 3: 59–68.
RU O SS, E ., 1992: Flechten im Kanton Luzern. U ntersuchungen zur Bioindikation und Floristik, sowie zur Immissionsökologie voralpiner H ochmoore. Veröff. Nat.-Mus. Luzern 3: 1–98.
SE AWA R D, M.R .D.; HITCH, C.J.B. (eds) 1982: A tlas of the lichens of the British Isles. Vol. 1.
Cambridge, Institute of Terrestrical E cology.
SCH E ID E G G E R, C.; DIE TR ICH, M.; FR E Y, M.; KE LLE R, C.; KU H N, N.; WILD I, E ., 1991: Z ur Waldflechtenflora des westlichen A argauer Mittellandes und ihrem Wandel seit 1960. Mitt.
A argau Nat.forsch. G es. 23: 175–191.
SCH E ID E G G E R, C.; FR E Y, B; ZO LLE R, S., 1995:Transplantation of symbiotic propagules and thallus fragments: methods for the conservation of threatened epiphytic lichen populations. Mitt.
E idgenöss. Forsch.anst. WSL 70: 41–62.
SE NN-IR LE T, B.; BIE R I, C.; HE R Z IG, R ., 1997: Provisorische R ote Liste der gefährdeten H öheren Pilze der Schweiz. Mycol. H elv. 9: 81–110.
UR MI, E ., 1993: D ie gefährdeten und seltenen Moose der Schweiz. R ote Liste. Bern, Bundesamt für U mwelt, Wald und Landschaft (BU WA L).
UR MI, E .; SCH NYD E R, N.; GE ISSLE R, P., 1990: A new method in floristic mapping as applied to an Inventory of Swiss Bryophytes. In: BO H N, U.; NE U H Ä U SL, R . (eds) Vegetation and flora of temperate zones. The H ague, A cademic Publishing. 21–32.
VO NA R BU R G, C., 1995: Seltene Makroflechten im Wägital, Innerthal (Kanton Schwyz). Mitt.
Nat.forsch. G es. Luzern 34: 115–127.
VU ST, M.; CLE R C, P., 1998: Inventaire de la flore lichénique suisse: liste rouge des lichens épiphytes et terricoles. Partie II: lichens terricoles. Travail effectué lors des deux premières années de projet. Meylania 14: 26–29.
WE LTE N, M., 1971: D ie Kartierung der Schweizer Flora. Boissiera 19: 97–105.
WE LTE N, M.;SU TTE R, R ., 1982:Verbreitungsatlas der Farn- und Blütenpflanzen der Schweiz. Basel, Birkhäuser. 716 and 698 pp.
WIRTH, V., 1987: D ie Flechten Baden-Württembergs. Stuttgart, U lmer. 528 pp.
WIRTH, V., 1995: Flechtenflora. 2. Aufl. Stuttgart, U lmer. 661 pp.
WIRTH, V.; SCH Ö LLE R, H .; SCH O LZ, P.; ER NST, G.; FE U E R E R, T.; GNÜ CH TE R, A .; HAU CK, M.;
JACO BSE N, P.; JO H N, V.; LITTE R SKI, B., 1996: R ote Liste der Flechten (Lichenes) der Bundesrepublik D eutschland. In: Bundesamt für Naturschutz (ed) R ote Liste gefährdeter Pflanzen D eutschlands. Schr.reihe Veg.kd. 28: 307–368.
WO H LG E MU TH,T., 1993: D er Verbreitungsatlas der Farn- und Blütenpflanzen der Schweiz (Welten und Sutter 1982) auf E DV: D ie A rtenzahlen und ihre A bhängigikeit von verschiedenen Faktoren. Bot. H elv. 103: 55–71.
ZING G, A ., 1988: Schweizerisches Landesforstinventar: A nleitung für die E rstaufnahme. Ber.
E idgenöss. Forsch.anst. WSL 304: 5–117.
