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Question: What are the extent and the possible causes of imperfect detection in lichens? Because lichens are sessile and lack seasonality, they should be easier to survey than animals that can move or plants and fungi with seasonal morphology, and one could therefore expect relatively high detection probabilities. Location: 826 standardised sampling plots across Switzerland. Methods: Using repeated detection/non-detection data from a national lichen survey conducted by professional lichenologists, we estimated the mean and variation in detectability for 373 tree-living species with a multi-species occupancy model. We also quantified the effect of species conspicuousness, identifiability and observer experience on detection probability. Results: The average detection probability for a single survey was unexpectedly low with an average of 0.49 (range across species: 0.25-0.74). Conspicuous species showed higher average detectability (0.56) than inconspicuous species (0.41), and identifiability as well as previous experience with a species substantially increased the probability of a person detecting it. Accounting for experience, the mean detection probabilities of observers ranged from 0.32 to 0.69. Conclusions: Our study confirms that detection probability per survey is often far below 1 also in sessile organisms, even when a standardised survey is conducted by experts. When species are seasonal (plants, fungi, etc.), survey areas are larger, or field personnel are less experienced, as is the case for many surveys and monitoring programs, detectabilities are likely to be substantially lower. We therefore argue that imperfect detection should systematically be considered in the survey design and data analysis also for sessile organisms.

Ecological impact assessments are required for all large infrastructure or exploitation projects because of their effects on environment and species. Methods that would make such assessments more standardised, efficient and reliable are highly desirable in today’s society, where many species are decreasing due to human-induced habitat modifications. This thesis evaluates the performance of a habitat index for Swedish bat species (bat habitat index, BHI), which has the potential to be used as a tool for impact assessments. Previous studies have shown that bats are negatively affected by large roads because they represent a barrier for movement and because the noise associated with the traffic impedes efficient foraging. The BHI takes the barrier effect of the highway into account by assigning it the lowest value for permeability. Acoustic effects in proximity to the highway are ignored by the BHI. For this study, 50 sites were inventoried for four nights using automatic ultrasound recorders to get an empiric measure of bat occurrence that could be compared to the BHI’s predictions and the distance to the highway E18 which crosses the study area. The correlation between the predicted values from the BHI and the observed bat activity (number of recordings) or species richness was tested using generalised linear mixed models. Among the models with the same response variable, the best-performing model was selected based on a bias-corrected AIC (Akaike Information Criterion). The results show that the BHI is a good predictor for the number of species that regularly occur at a given site (i.e. species that were observed in a minimum of three out of four nights), but not for the total number of species. The BHI performed also much better at predicting the activity of forest-living species than overall bat activity. Instead of the expected positive correlation between the distance to the highway and bat activity, the observed negative correlation suggests that the BHI overes, Populärvetenskaplig sammanfattning Miljökonsekvensbeskrivningar (MKB) krävs vid all planering av infrastruktur- och exploateringsprojekt. En MKB består delvis av konsekvensbeskrivningar för arter, eftersom stora projekt kan påverka djur och andra organismer negativt genom att förstöra lämpliga boplatser och födoområden (habitatförlust) eller genom att förhindra spridning (barriäreffekt). Syftet med detta arbete var att utvärdera ett index som förutsäger förekomsten av fladdermöss beroende på lokala och regionala miljöförhållanden. Indexet (bat habitat index, BHI) är baserat på tre grundkartor som representerar täthet av insekter, fladdermössens flygpreferenser och var det finns möjliga koloniplatser för dräktiga honor. De grundkartorna baseras på det senaste kunskapsläget och är skapade av experter utgående från tillgängliga terräng- och habitatkartor samt resultat från olika inventeringar. Genom att definiera motorvägar som olämplig flygmiljö ingår barriäreffekter av motorvägar i indexet vilket gör det speciellt användbart i MKB för konstruktion av stora motor- eller järnvägar. Inom denna studie inventerades 50 lokaler fördelade över ett område på ca 850 km2 i Stockholms län under juli månad 2017. På varje lokal sattes automatiserade inspelningsboxar som registrerar ultraljud (och alltså fladdermössens läten) upp och boxarna spelade in allt ultraljud under fyra nätter. Varje lokal fick ett värde för fladdermössens aktivitet (antal inspelningar), artantalet över samtliga fyra nätter och antalet arter som registrerades regelbundet (minst tre av fyra nätter). För att analysera hur väl BHIs förutsägelser och avstånd till motorvägen korrelerar med de observerade värdena för aktivitet och artantal, användes ett statistiskt kriterium som kallas för Akaike Information Criterion (AIC) och som tillåter jämförelser mellan olika modeller. Resultatet från denna analys visar att BHI är bra på att förutsäga antalet arter som regelbundet använder en lokal, men att indexet inte är

Årets vårexkursion gick 2018 till Värmlandsnäs och Lurö i Vänern. Följande personer deltog under helgen: Ulf Arup, Toni Berglund, Linnea Ekman, Stefan Ekman, Mikael Hagström, Robin Isaksson, Linda Johannesson, Barbara Klein, Jon Klepsland, Alica Kosuthova, Björn Owe-Larsson, Gesa von Hirschheydt och Martin Westberg. Under exkursionen noterades totalt 16 nya arter för Värmland, varav en ny för Skandinavien, nämligen Halecania giraltiae.

We present taxonomic, distributional and ecological notes on Fennoscandian crustose lichens and lichenicolous fungi, based on new collections as well as revision of herbarium material. Two new combinations are proposed: Frutidella furfuracea comb. nov. for F. pullata and Puttea duplex comb. nov. for Fellhanera duplex. Lecidea byssoboliza, L. carneoglauca and Variolaria torta are all reduced to synonymy with Bacidia antricola, Bacidia invertens is synonymized with B. igniarii, B. atrolivida with Mycobilimbia tetramera, and Gyalidea fruticola with Thelenella pertusariella. A new description is provided for Micarea hylocomii. 25 species of lichens and lichenicolous fungi are reported as new to Finland, Norway and/or Sweden: Absconditella lignicola (Norway), Bacidia antricola (Norway), B. polychroa (Norway), B. pycnidata (Sweden), Bacidina adastra (Sweden), Biatora veteranorum (Norway), Briancoppinsia cytospora (Finland), Catillaria scotinodes (Norway), Cliostomum subtenerum (Norway), Dirina fallax (Sweden), Fellhaneropsis almquistiorum (Norway), Gyalidea subscutellaris (Sweden), Lecania inundata (Norway), L. suavis (Norway), Micarea capitata (Norway), M. deminuta (Norway), M. hylocomii (Sweden), M. lynceola (Sweden), M. soralifera (Sweden), M. subconfusa (Sweden), Mycoblastus sanguinarioides (Finland, Sweden), Paralecia pratorum (Sweden), Puttea duplex (Sweden), Sarcogyne algoviae (Finland) and Toninia subnitida (Norway). Lectotypes are designated for Bacidia antricola, Lecidea byssoboliza, Lecidea carneoglauca, Lecidea subconfusa and Lecidea submoestula.