Leptogium rivulare is a globally rare lichen with very restrictive habitat requirements (the periodically inundated substrate, bases of trees or rocks; Jørgensen 2007). Potential habitats are easily diminished oreven eliminated by natural processes (e.g. interference with the extent or duration of spring flooding) or the deterioration of habitats may be caused by human activities. This taxon has only a few rich subpopulations of stable condition worldwide (in Republics of Marii El and Komi, Russia, and in Ontario, Canada). In most documented locations it is represented by single or few thalli although suitable substrate is present and careful searching for the species has been performed. In six historical locations (Canada, Estonia, Finland and USA), this taxon is considered extinct.
Assessment Considering criterion A, information about population reduction is based on records of this species. Altogether 30 localities in Europe and North America are documented and of these six are considered extinct (single localities in Estonia and Finland, subpopulations in Illinois and Vermont in USA, and two subpopulations in Ontario, Canada). Population size reduction is estimated at 20% over the last three generations. This is less than 30% and thus, this species does not qualify for Vulnerable. However, future decline is projected in quality of habitat as the largest subpopulations in Canada (Ontario, Ottawa) are under threat of urban development and recreational activity. In Russia, for example in the Republics of Marii El and Komi, the pollution of rivers is another potential threat for this species as only unpolluted water streams are considered suitable for it. This species is assessed as Near Threatened.
Assessor/s: Randlane, T.; Reviewer/s: Scheidegger, C. & McMullin, T.; Contributor(s): Aptroot, A., Spribille, T., Perez-Ortega, S & Paukov, A.
Bibliography:
Bogdanov, G.A., Abramov, N.V., Urbanavichus, G.P. & Bogdanova, L.G. (2013) Red Data Book of the Republic Marij El. Plants and Fungi. (In Russian). Mrijasky State University., Yoshkar-Ola.
Bogdanov, G.A. & Urbanavichus, G.P. (2008) Lichen species new and rare to Russia from the Republic of Marii El. (In Russian). Botanicheskii Zhurnal (St. Petersburg) 93(6): 944–950.
Boom, P.P.G. & Jansen, J. (2002) Lichens in the upper belt of the Serra da Estrela (Portugal). Österr. Z. Pilzk.11: 1-28.
COSEWIC (2004) Assessment and status report on the flooded jellyskin Leptogium rivulare in Canada. Committee on the Status of Endangered Wildlife in Canada, Ottawa.
Halonen, P. (1996). Lichens of the former Kutsa Nature Reserve. Oulanka Reports16: 63–68.
Hermannson, J. & Kudryatseva, D. (1995) Notes on the lichens of the Pechoro-Ilych Zapovednik, Komi Republic, Russia. Graphis Scripta7: 67–78.
IUCN (2015) The IUCN Red List of Threatened Species. Version 2015-4. Available at: www.iucnredlist.org. (Accessed: 19 November 2015).
Konstantinova et al. Red Data Book of the Murmansk Region. Edition 2. Available at:http://ias.kgilc.ru/redbook/?q=Lichens. (Accessed: August 2015).
Motiejūnaitė, J. & Golubkov, V.V. (2005) Cyanolichens of freshwater aquatic and subaquatic habitats in Lithuania and Belarus. Botanica Lithuanica11(1): 35–40.
Motiejūnaitė, J., von Brackel, W., Stončius, D. & Preikša, Ž. (2011) Contribution to the Lithuanian flora of lichens and allied fungi. III. Botanica Lithuanica17(1): 39–46.
Paukov, A. & Teptina, A. (2012) New records of lichens from Middle Urals, Russia. Folia Cryptog. Estonica49: 39–43.
Pystina, T.N., Hermansson, J. & Kustysheva, A.A. (1999) New data on the distribution of a rare species Leptogium rivulare (Collemataceae, Lichenes). Botanicheskii Zhurnal (St. Petersburg) 84(9): 126–13.
Randlane, T. (1987) Leptogium rivulare (Ach.) Mont. – a new rare lichen species in Estonia. Folia Cryptog. Estonica25: 8–11.
Roux, C. (2012) Liste des lichens et champignons lichénicoles de France. Bull. Soc. linn. Provence, n°spécial 16: 1–220.
Santesson, R., Moberg, R., Nordin, A., Tønsberg, T. & Vitikainen, O. (2004) Lichen-forming and lichenicolous fungi of Fennoscandia. Museum of Evolution, Uppsala University, Uppsala.