Sarcosoma globosum is a well known, conspicuous and much studied fungus with its main distribution in northern Europe. It has decreased throughout its range, and disappeared from many parts of Europe. The prime cause for decline is changing land management, above all the practice of clear cutting old-growth forests. This causes the species to disappear. The practice of allowing cattle to graze in forests, which was beneficial for this fungus, has largely ceased, and that is also having a negative impact. The fungus is nationally red-listed in 10 European countries, and is thought to be extinct in several central European countries. The status of the species in Russia is a little unclear. The status and trend of the population is inferred from field observations combined with the known habitat decline. Past, ongoing and future habitat declines are estimated to impact negatively on all populations of S. globosum, and the future looks bleak for this species. Estimated decline of area and quality of appropriate forest habitat has been and will continue to be be just under 30 % over 50 years. The length of evaluation period used for these estimates (50 years = three generations) follows recommendations of Dahlberg and Mueller (2011). Only criterion A applies as the species is widely distributed and the estimated total population size disqualifies use of criteria B-D. It is listed as Near Threatened because it almost qualifies for listing as Vulnerable under criteria A2c+3c+4c .
Sarcosoma globosum is a circumpolar boreal and hemiboreal species with its main distribution in northern Europe (Dahlberg and Croneborg 2003, Nitare 2009). The most dense distribution occurs in southeastern and, to a lesser degree, northeastern, Sweden. It is also well distributed in Finland and certain areas in Russia, although less well documented, may also be important. The few occurrences in central Europe represent small, fragmented subpopulations close to the edge of its natural range. It occurs rarely in eastern parts of North America, but those records may also include similar but different, misidentified species. It is not known from western North America.
Globally, the main stronghold of Sarcosoma globosum is Sweden, where it is well known and has been much looked after since the early twentieth century (Nitare 2009). There have been more than 2,000 reports from 150 known localities, with an estimate of 300 localities in total and a suspected population of 6,000 mature individuals in Sweden (ArtDatabanken 2015). It is rare in Finland, with 80 reported observations since 1915 (Ohenoja, Kaukonen and Routsalainen 2013 ). Information about its occurrence in Russia is incomplete, but it has been reported from many regions and may be locally common. It is rare outside Sweden, Finland and Russia. It has become nationally extinct in some European countries and is reported to decline throughout its range. A Species Action Programme for Sarcosoma globosum 2010-2014 in Sweden provided a compilation of the species biology, status in Sweden and Europe as well suggestions of needed actions for conservation (Nitare 2009). The programme (in Swedish, with an English summary) can be downloaded.
Population Trend: decreasing
The main threat is decline and degradation of habitat through logging. In Sweden, the post-1950 abandonment of forest cattle grazing (which was beneficial for this fungus) has also been significant. The fungus disappears after clear-cutting and seems not to re-colonize the managed forests which replace the original habitat. There are no reports of the fungus in plantations. Most of the appropriate spruce forests in northern Europe, >90%, are managed with a forest rotation-time of 70-100 years. The clear-cutting at the end of that period reduces the potential habitat, and decline is expected to continue at a rate of about 1%/year. Most populations located in sites outside protected areas are expected to disappear in the future. The ending of forest cattle grazing has resulted in more dense forest habitats which are unsuitable for this fungus.