Romagniesiella clavus is a species-of semi-natural grasslands which were, for a long time, managed in a traditional way. These habitats are dependent on moderate grazing intensity and/or hand mowing without using artificial fertilizers and pesticides. They are rapidly disappearing worldwide due to changes in land use (agricultural intensification and decline of traditional farming practice) and increased use of fertilizers and pesticides, and as these habitats disappear so do the fungal species that rely on them. This species is small, difficult to recognize and only known from relatively few localities. It is not known to occur outside of Europe (although it has close relatives in North America) and it is very rare in all countries where it occurs. Decline in area and quality of available habitat has approached (or possibly exceeded) 30% over the last 50 years; the decline in population size over this time has probably been higher. This decline in habitat is expected to continue even more rapidly over the next 50 years (approximately three generations: one generation for R. clavus is around 17 years). Currently the population size is estimated to be c. 6,000 mature individuals, with no subpopulation containing >1,000 mature individuals. Additionally, a reduction in population size is suspected of more than 30% over the last 50 years and a decline suspected to continue and caused by habitat loss and degradation. This meets the threshold for VU A2c+3c+4c; C2a(i).
Current Name:
Romagnesiella clavus (Romagn.) Contu, Matheny, P.-A. Moreau, Vizzini & A. de Haan, in Matheny, Moreau, Vizzini, Harrower, De Haan, Contu & Curti, Syst. Biodiv. 13(1): 36 (2014) [2015]
Romagniesiella clavus is a species-of semi-natural grasslands which were, for a long time, managed in a traditional way. These habitats are dependent on moderate grazing intensity and/or hand mowing without using artificial fertilizers and pesticides. They are rapidly disappearing worldwide due to changes in land use (agricultural intensification and decline of traditional farming practice) and increased use of fertilizers and pesticides, and as these habitats disappear so do the fungal species that rely on them. This species is small, difficult to recognize and only known from relatively few localities. It is not known to occur outside of Europe (although it has close relatives in North America) and it is very rare in all countries where it occurs. Decline in area and quality of available habitat has approached (or possibly exceeded) 30% over the last 50 years; the decline in population size over this time has probably been higher. This decline in habitat is expected to continue even more rapidly over the next 50 years (approximately three generations: one generation for R. clavus is around 17 years). Currently the population size probably is below 10,000 mature individuals. Despite this small population size, the species is nevertheless assessed Vulnerable because it may have been overlooked. However, a reduction in population size of more than 30% over the last 50 years and a decline suspected to continue and caused by habitat loss and degradation meets the threshold for VU A2c+3c+4c.
This tiny species, which may be difficult to identify and thus overlooked is present in Europe but rare everywhere. It is also reported from North Africa (Morocco) and from two records in Irkutsk Oblast. Records from North America (Krieglsteiner and Gminder 2010) are doubtful.
Romagnesiella clavus is as a rare species throughout all the range where it is known. Usually, there are only a few records from each country. GBIF reports about 84 records, all in Europe, but it is also present in North Africa (Morocco). As it might have been overlooked, the number of localities is estimated to be at least 50 times more, i.e. up to 1500. We conservatively estimate the number of different genotypes to be two per locality, on average to correspond to four mature individuals (Dahlberg and Mueller 2011). Hence, then total population size is estimated not to exceed 6,000 mature individuals, with each subpopulation containing <1,000 mature individuals. The population is considered to be decreasing in many known countries of occurrence, caused by lack of traditional methods of grassland management. This decrease is inferred to be 30% over 30 years (past, future and ongoing) but may actually be as high as 50% over three generations (50 years; e.g., 1975-2025) and even higher over longer time-frames. This species is included in e.g. the national Red List of Austria as CR (Dämon and Krisai-Greilhuber 2017), in the German Red list as an extremely rare species (BfN 2016).
Population Trend: Decreasing
Romagnesiella clavus grows in mycologically rich but nutrient-poor seminatural grasslands, often on acidic soil in grasslands surrounded by heath, but also on calcareous, mineral-rich, sandy or alluvial substrates in pioneer or also disturbed habitats including fixed coastal dunes and path sides among mosses and grasses. It occurs scattered but never abundant. Semi-natural grasslands are rapidly disappearing due to changes in land use (see Threats and Population sections). Almost all localities of the species are in semi-natural grasslands and some few times in shub-pastures on dry open sandy habitats. It is fruiting from September to November.
Like other species dependent on semi-natural grasslands, Romagnesiella clavus is threatened by habitat loss due to decreasing extensive grassland management. The main reasons for decline are agricultural intensification (primarily the application of phosphorus) and the reduction of area and quality of available habitat. In urban and suburban environments, the application of lawn fertilisers, fungicides and moss killers can also affect the species (Mitchell 2000). Nitrogen deposition could also be impacting the species’ habitat. According to NATURA 2000 reports (Calaciura and Spinelli 2008), grassland habitats are steadily decreasing, mainly due to abandonment or change in land use. The total area of grassland in the EU fell by an average of 12% between 1975 and 1998, with increases in only very few areas. In areas where the habitat is still present, lack of management results in a continuing decrease in the range of many species due to decrease in habitat quality. According to the Food and Agriculture Organization of the United Nations (FAO), the area of grasslands in the EU declined by 12.8% from 1990 to 2003; only a few Member States managed to avoid this trend (Food and Agricultural Organisation of the United Nations 2006: FAO Statistical Yearbook – FAOSTAT). Pressure caused by land use changes on grassland habitats is steadily increasing. More than 75% of the grassland habitats in the EU are in an unfavourable conservation status, according to draft data provided by Member States under Article 17 of the Habitats Directive. Over the past decade, grassland butterflies have suffered large declines in Europe, with a reduction of abundance by almost 50%, with little sign of improvement (SEBI 2010 Biodiversity Indicators).
Site protection and management of habitats are important conservation actions for this species. Some grasslands with high species diversity and conservation value are situated within national parks, nature monuments, or nature reserves. However, these grasslands need careful management plans, including grazing which is not always present even within strictly protected areas. This situation results in continual decrease of habitat quality even if sites are protected from exploitation.
Monitoring of the species localities is highly desirable. Population genetic studies on the physical extent of genets (and how many ramets per genet) would improve estimates of “mature individuals”.
The species is not in any use.
Country | Trend | Redlisted |
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