Tillstånd och trender för arter och deras livsmiljöer

2015 års upplaga av den svenska rödlistan är den fjärde i ordningen. Den är baserad på IUCN:s rödlistningskriterier och revideras vart femte år. I rödlistan bedöms risken som enskilda arter av djur, växter och svampar löper att försvinna från Sverige. Bedömningen utförs av ArtDatabankens medarbetare i samverkan med över 100 externa experter, indelade i 14 expertkommittéer för olika organismgrupper. Under arbetet med 2015 års rödlista har tillstånd och trender bedömts för 21 600 arter och 1 318 lägre taxa (apomiktiska arter, underarter och varieteter), sammanlagt ca 22 900 taxa. Av de bedömda arterna klassificerades 2 029 som hotade (kategorierna CR, EN och VU) och 4 273 som rödlistade (inkluderar även kategorierna NT, RE och DD). Förhållandet mellan antalet rödlistade och antalet bedömda arter ar 19,8 %, vilket är ungefär samma värde som 2010 och 2005. I denna rapport jämförs antalet och andelen rödlistade arter mellan olika organismgrupper, biotoper, substrat och påverkansfaktorer. Texten ar indelad i en allmän del och åtta kapitel inriktade på olika landskapstyper. Landskapstyperna utgör en grov indelning av landets miljöer enligt följande kategorier: Skog, Jordbrukslandskap, Urbana miljöer, Fjäll, Våtmarker, Sötvatten, Havsstränder och Havsmiljöer. Skogen och jordbrukslandskapet är de artrikaste landskapstyperna med 1 800 respektive 1 400 arter som har en stark anknytning dit, och ytterligare flera hundra arter som förekommer där mer sporadiskt. De faktorer som påverkar flest rödlistade arter i Sverige är skogsavverkning och igenväxning, som båda utgör ett hot mot vardera ca 30 % av de rödlistade arterna. Avverkning minskar arealen av skog där naturliga strukturer och naturlig dynamik upprätthålls, och den orsakar därmed förlust av livsmiljöer. Igenväxning orsakas av ett antal faktorer, bland annat upphörande hävd (bete och slåtter), gödsling, trädplantering och brist på naturliga störningsregimer som t.ex. regelbundna översvämningar kring vattendrag och sjöar. Andra viktiga påverkansfaktorer är fiske, torrläggning av våtmarker, tillbakagång hos värdarter (främst alm och ask som drabbats av invasiva svampsjukdomar), klimatförändringar och konkurrens från invasiva arter. IUCN:s rödlisteindex beräknas för ett urval av de bedömda organismgrupperna. Rödlisteindex visar att skillnaderna mellan rödlistorna från 2000, 2005, 2010 och 2015 är små. Ett par undantag finns dock. Groddjur och stora däggdjur har fått en något förbättrad situation sedan 2000. Totalt förefaller det ändå som att trycket mot Sveriges artstock har förblivit relativt konstant under de senaste 15 åren

Recommendations for the use of critical terms when applying IUCN red-listing criteria to bryophytes

The IUCN Red List is recognised as a robust system for assessing the risk of extinction to organisms, but there are difficulties in applying the criteria to bryophytes and other clonal and colonial organisms. Three critical terms are addressed – generation length, mature individual and severe fragmentation – and definitions given in order to facilitate the use of the IUCN Red List criteria for bryophytes. These recommendations provide a pragmatic and effective way of using the IUCN Red List process for bryophytes and may have a wider application to other clonal organisms

Mossfloran på Ölands alvar – ett nytt inventeringsprojekt.

In 2011 a field survey of the bryophyte vegetation and flora of Stora Alvaret, the largest continuous alvar area in Sweden situated on the Baltic island of Öland (SE Sweden), was initiated. A number of transects crossing the alvar area from west to east will be surveyed. The aim of the investigation is to try and elucidate the realtionship between the bryophyte flora and environmental parameters such as soil chemistry, soil wetness, soil depth, disturbances from livestock grazing and the geographic position on the island at different spatial and temporal scales. The survey will be conducted both in early spring and late autumn and will run for several years to enable analyses of the impact of season and climatic variations

Mossinventeringen av Stora alvaret 2011–2013

During the period from 2011 to 2013, a group from Mossornas Vänner made a field survey of bryophyte flora of Stora alvaret situated on island Öland in the Baltic Sea. The result of the survey was published in Journal of Bryology 2018 (see the reference at the end of the article). We analysed the occurrence of bryophyte species and variation in species richness across 674 plats (0.5 m x 0.5 m) in alvar vegetation (grass/and on limestone pavement with thin or no soil) in relation to substrate characteristics - chemistry, inundation frequency, grazing pressure and geographical variables. We found 148 taxa, including 11 nationally red-listed ones. Species richness per plot was signifzcantly associated with substrate type, positive/y associated with pH and grazing intensity, but negative/y associated with soil depth. However, richness of species typical of or restricted to , alvar habitals responded different/y from richness of species more common in other habitats. Typical alvar species were favoured by high pH, shallow soil and low phosphate availability, while generalists preferred relative/y low pH, higher phosphate availability and arganie or mull soil types. Distance from the alvar margin had only weak effects. Concerning the effects on individual species and community composition, inundation frequency and pH were found to have the largest effects, although other jaetors (substrate type, soil depth, bare soil, bare stone, phosphate availability and grazing pressure) were more important for same individual species, stressing the importance of microsite variability and variability in management for regional species richness. From a conservation perspective, it is concluded that grazing is generally positive whilst factors increasing phosphate availability may disadvantage the typical alvar species, and proximity to the alvar margin is not a major problem

Bryophyte conservation for the future.

he conservation process involves recognizing and listing rare and decreasing species, recording their distribution, biology and specific threats, proposing conservation programmes, and executing these programmes. There are large gaps in our knowledge about bryophytes which must be filled before their conservation can be selective. These include taxonomy, bryogeography, habitat demands, natural dynamics, dispersal ability, population structure and genetics. In a long-term perspective, conservation must strive towards creating possibilities for the species to survive without too much artificial support. It is particularly important to focus on habitats and sites where the species may survive naturally during unfavourable periods. In the short term, creating nature reserves with large populations can save a species until our knowledge has increased. In practice, bryologists must be more active in collecting data and informing the conservation organizations and governmental authorities about the need for conservation

Determinants of bryophyte species composition and diversity on the Great Alvar of Öland, Sweden

Factors driving the species richness and distribution of bryophytes are poorly studied and not well understood, particularly in grasslands. We analysed the occurrence of bryophyte species and variation in species richness across 674 plots (0.5 m× 0.5 m) in alvar vegetation (grassland on limestone pavement with thin or no soil) on Öland (Sweden) in relation to substrate characteristics and chemistry, inundationfrequency, grazing pressure and geographical variables. We found 148 taxa, including 11 nationally redlisted ones. Species richness per plot was significantly associated with substrate type, positively associated with pH and grazing intensity, but negatively associated with soil depth. However, richness of species typical of, or restricted to, alvar habitats responded differently to richness of species more common in other habitats. Typical alvar species were favoured by high pH, shallow soil and lowphosphate availability, while generalists preferred relatively low pH, higher phosphate availability and organic or mull soil types. Distance from the alvar margin had only weak effects. Concerning the effects on individual species and community composition, inundation frequency and pH were found to have the largest effects, although other factors (substrate type, soil depth, bare soil, bare stone, phosphateavailability and grazing pressure) were more important for some individual species, stressing the importance of microsite variability and variability in management for regional species richness. From a conservation perspective, it is concluded that grazing is generally positive whilst factors increasing phosphate availability may disadvantage the typical alvar species, and proximity to the alvar margin is nota major problem