Updated Distribution of Endangered Psathyrella ammophila in Poland – New Localities on Wolin Island

Psathyrella ammophila is a psammophilous fungus most frequently inhabiting seashore beaches, sand dunes and sandy inland areas. Although it is a widely spread species, in some countries it is rare or threatened, including Poland, where it is classified as “endangered” (E). In Poland, P. ammophila has been found in 26 localities, including 14 new reports after 1970. We present two new Polish localities from white sand dunes at the western shore of the Baltic Sea (Wolin Island). Moreover, ecological information and macroscopic and microscopic features of the basidiocarp based on collected samples are presented. The problem of the disappearance of dunes as a primary habitat of P. ammophila is also discussed.


Introduction
Climatic changes, which result in the elevation of the sea and ocean levels as well as more aggressive abrasion of seashores (Jakusik et al., 2012;Prasad & Kumar, 2014;Räisänen, 2017) lead to, among other consequences, degradation and disappearance of habitats such as mobile white or grey dunes (e.g., Namura-Ochalska, 2004a, 2004bTylkowski, 2017). The greatest losses of such habitats have been observed in Southern Europe, which is connected with the development of tourism and strong urban pressure (Janssen et al., 2016). The above factors limit the habitats of psammophilous plants, animals, and fungi, which may lead to permanent extinction. Considering the modest biological variability of seashore dunes, even a minimal disturbance in their biological balance may be dangerous to the survival of species strongly dependent on this habitat. This especially refers to a small group of dune-inhabiting macrofungi, including Hohenbuehelia culmicola Bon, Laccaria maritima (Theodor.) Singer ex Huhtinen, Phallus hadriani Vent., and Psathyrella ammophila (Durieu & Lév.) P. D. Orton (Bujakiewicz & Lisiewska, 1983;Fraiture & Otto, 2015;Høiland, 2012;Watling & Rotheroe, 1989). The fungi are vulnerable because of their specific requirements of sandy nutrient-poor sites with initial vegetation (Fraiture & Otto, 2015). This type of vegetation is rare in Europe and mainly threatened by coastal management and by nitrogen deposition from air pollution (Houston, 2016;Ozinga et al., 2013).
This paper aims to provide ecological notes, new localities for P. ammophila on the Wolin Island, and the resulting update of the distribution of this species in Poland. Moreover, the macroscopic and microscopic features of the basidiocarps of this fungus were presented.

Material and Methods
Psathyrella ammophila basidiocarps were collected from Miedzyzdroje and Świnoujście (both on Wolin Island) in August 2012 and October 2019, respectively. The descriptions of the basidiocarp morphology and ecological characteristics of this species are based on original material, accompanied by information from literature. The microscopic structures were observed and measured using a Zeiss AxioLab light microscope (LM). Dimensions of pleurocystidia, cheilocystidia, basidia (without sterigmata), and spores are based on 10-20 measurements per specimen from our collections. Size ranges of the microscopic features are given as follows: (minimum value-) first decile -ninth decile (-maximum value). Scanning electron microscope (SEM) images were captured in the Center of Molecular Biology and Biotechnology, Environmental Research Laboratory, University of Szczecin (Poland). The specimens were identified based on their macroscopic and microscopic features, using monographs by Kits van Waveren (1977, 1985, and Örstadius and Knudsen (2012).
The distribution of P. ammophila in Poland is presented on a cartogram according to the ATPOL gird square system as used by Wojewoda (2000). The cartogram is based on our investigations and all available published and unpublished data. In order to illustrate the changes in the distribution of this species, we presented the localities in two time periods: before 1970 and in 1970 or after. The fungal nomenclature and the synonyms were given according to the Index Fungorum (http://www.indexfungorum.org/) database. The names of vascular plants follow the description by Mirek et al. (2002), and Jalas and Suominen (1973), and the names of the plant communities are given according to the data in the source literature. The collected specimens of P. ammophila were deposited in the Herbarium of Szczecin University (SZUB-F), Poland.
This psammophilous species was also recorded, although significantly less frequently, on more stabilized habitats such as compact turf developed on sands and dunes overgrown by trees, e.g., Pinus halepensis Mill. and P. pinea L., as well as on anthropogenic localities, e.g., on state beaches and boulevards (Pando & Fernández, 2001, and references therein).

Discussion and Conclusions
Although P. ammophila is a widely spread fungus, mainly in Europe (Dämmrich et al., 2020;Dämon & Krisai-Greilhuber, 2016;Maletti, 2014;Örstadius & Knudsen, 2012;Perini & Venturella, 2008), the current knowledge on its geographic distribution is still incomplete and requires verification. For instance, the information found in the literature on the occurrence of this fungus in the Czech Republic is incorrect (Vašutowá, 2006). In Poland, after 1970, 14 localities of this species were reported, including 13 localities identified in the last 10 years, which constitute 50% of all 26 localities recorded to date. The occurrence of P. ammophila in the Kampinos Forest, where it was observed in the 1960s by Rudnicka-Jezierska (1969), was not confirmed (Karasiński et al., 2015). In the last few years, this fungus has mainly been noted in the north-eastern part of the Polish seashore, e.g., the Hel Peninsula (Kujawa & Gierczyk, 2013;Kujawa et al., 2020), where it was found in the 1930s and reported by Teodorowicz (1936) as a very common species. Two new localities are situated further West, on Wolin Island. They neighbor a few other localities of the north-eastern seashores of Germany, including the Uznam and Rugia islands (Dämmrich et al., 2020).
The typical habitat of P. ammophila includes mobile white sand dunes, which occur along seashores and are classified as Natura 2000 habitats (Janssen et al., 2016). This habitat is subjected to strong man-made-disturbances due to the escalating development of tourism in the last 100 years, which has led to a reduction of its areas. It can be forecast that the pressure from tourism will grow and fungi habitats will further degrade. Apart from anthropogenic factors, natural factors such as abrasion of seashores and vegetation succession also have a negative effect on the habitats of the fungus (Jakusik et al., 2012;Janssen et al., 2016;Leuschner & Ellenberg, 2017;Tylkowski, 2017). According to Leuschner and Ellenberg (2017), a major part of the German and Polish shore of the Baltic Sea has been eroded, causing the disappearance of sand dunes, which are otherwise colonized and stabilized by plants and fungi, including P. ammophila (Høiland, 2012;Watling & Rotheroe, 1989).
Psathyrella ammophila is a very important fungal element of the Baltic seashore dunes, as only a few species are capable of colonizing mobile dunes. Due to the progressive degradation of these ecosystems and climatic changes, the perspective for the next several years seems unfavorable to P. ammophila. Considering all the above facts, this fungus should be listed as a protected species.