Checklist of aphyllophoroid fungi ( Basidiomycota ) of the Archipelago Sea National Park , Southwest Finland

Aphyllophorales is an unnatural group of fungi, which are mainly wood decaying saprobes but also mycorrhizal or parasites, and are phylogenetically diverse. In this study we focused on polypores, corticioids and hydnaceous wood decayers with the common feature to form basidiocarps on woody substrates or litter. The checklist is mainly based on material collected during 2008–2010 in the Archipelago Sea National Park and its surrounding area in Southwest Finland. The aim of the study was biogeographical and ecological research of wood-inhabiting aphyllophorales and their habitats. We list 303 species from the study area. It is 40% of all known species (756) of the target groups recorded in Finland. Six species new to Finland were collected during the field work, which are already reported earlier. Our collections include 26 species, which can be defined as rare, with only five or less earlier records in Finland, and 18 species that are red-listed.


INTRODUCTION
Aphyllophorales (or aphyllophoroid fungi), is an unnatural group of fungi.They are mainly wood or litter decaying saprobes, mycorrhizal or parasites and are phylogenetically strongly diverse.In this study, however, the groups that were studied (polypores, corticioids, hydnaceous wood decayers) have a common feature: they all form basidiocarps on woody substrates or litter, and are traditionally collected and studied by polyporologists and/or corticologists.Hydnaceous soil dwelling fungi are excluded (e.g., genera Bankera, Hydnellum, Hydnum) like all pileate tremelloid, clavarioid and ramarioid taxa.On the other hand, resupinate, corticioid heterobasidioid fungi are included.
The first extensive checklist of aphyllophoroid fungi in Finland (Kotiranta et al. 2009) lists altogether 756 species of our target groups.The majority of these, 489 species, occur also, or even solely, on the coastal region of southwestern Finland, including the Archipelago Sea (Kotiranta et al. 2009).After publishing the Finnish checklist, many new corticioid and polypore species have been reported from Finland (Kunttu et al. 2009(Kunttu et al. , 2010(Kunttu et al. , 2011(Kunttu et al. , 2012(Kunttu et al. , 2013;;Kotiranta and Shiryaev 2013;Spirin et al. 2013a).There are no earlier large scale biogeographical or ecological studies of Aphyllophorales on the Archipelago Sea, and only one general publication of macrofungi (Vauras 2000).
In this checklist, the Archipelago Sea is defined as the National Park of Archipelago Sea and its surrounding area (Figure 1).This national park is also known as Archipelago National Park or Southwestern Archipelago National Park.The Archipelago Sea has the highest biodiversity in Finland and there occur many species and biotopes not found elsewhere in Finland (Lindgren 2000;Lappalainen 2004).

MATERIALS AND METHODS
The Archipelago Sea-part of the Baltic Sea-is the most southwestern part of the Finnish coastline and includes 40,000 islands or islets.The area belongs to hemiboreal vegetation zone and is part of the biogeographic province of Regio aboënsis (Ahti et al. 1968;Hansen and Knudsen 1997).The map of Finnish forest vegetation zones is also on the website of Finland's environmental administration (2009).
The Archipelago Sea National Park was founded in 1983.Because the national park has fragmentary composition, there is a much wider, unprotected area around it, which covers 151 km 2 of land and 2,896 km 2 of sea (Figure 1).It contains about 8,384 islands or skerries (size at least 100 m 2 ).However, only 23% (35 km 2 ) of land area is protected by the national park legislation.More details of this area are in Lindgren (2000) and LISTS OF SPECIES collections, and 6,318 observations.Some additional material was collected during occasional field trips to this area.Some earlier records were published by Vauras (2000).
The nomenclature of the genus Hyphodontia sensu lato follows Hjortstam and Ryvarden (2009), of the polypores mainly Niemelä (2005), and of other groups mainly Kotiranta et al. (2009).Some recent combinations are not found in any manuals, and the reader is referred to Miettinen and Larsson (2010), Miettinen et al. (2012) and Spirin et al. (2013b).The Finnish national red-listing evaluation of the IUCN Red List Categories is according to Kotiranta et al. (2010).

RESULTS
A total of 303 species are listed in alphabetic order regardless of their systematic position (Table 1).This is 40% of all known species in these species groups in Finland and ca.62% of species found earlier from the the coastal region of southwestern Finland.
During the field work six species new to Finland were Metsähallitus (2014).
The investigated area has some special features: the growing season is long (180-195 days), the diversity of biotopes and tree species is high, herb-rich forests are common, wooded pastures and semi-natural woodlands and meadows are still grazed, especially on larger islands, traditionally by domestic animals.These kinds of rural landscapes are more common in the archipelago than elsewhere in the province of Southwest Finland (Lehtomaa 2000).
According to Kunttu et al. (2014), the national park with its surroundings is inhabited by 467 Threatened and Near Threatened taxa, and the number of species is high in many organism groups (Lindgren 2000(Lindgren , 2001)).The habitat diversity is high and there are 45 Natura 2000 habitat types according to the European Union's Habitats Directive (Lindgren 2000; Varsinais-Suomen ELY-keskus 2013), many of them rare or unique (Lindgren et al. 2001).
Small islands have been saved from intense forestry but household use for building, fodder for domestic animals and collecting of firewood have occurred.Lindgren et al. (2001) list many biologically highly valuable biotopes in the archipelago, including different types of forests.In comparison with forests of other areas in Southern Finland, the highest volume of dead wood was measured in the archipelago regions (Finnish Forest Research Institute 2012; P. Kunttu, unpubl.).
Panu Kunttu (PK) surveyed and collected the material during the summers and autumns 2008-2010.This study covers 29 islands (total 1,320 ha of which 1,074 ha forested), 6,648 dead trunks and branches, 2,659   (year 1997) also derives the only Finnish specimen of Sidera vulgaris (Fr.)Miettinen.The checklist includes 26 species which can be defined as rare, or at least seldom collected, with five or less earlier records in Finland (Kotiranta et al. 2009).

DISCUSSION
The number of identified species (303) in this study is among the highest in Finland if compared to the area studied.This can be explained for example by the high diversity of habitats and host tree species and the relatively high volume of dead wood.Not fully identified material of genera such as Thelephora and Xylodon are not included and may represent undescribed species.
The 18 nationally red-listed species belong to the following threat categories: Endangered (1 species, EN), Vulnerable (4, VU), Near Threatened (11, NT), and Data Deficient (2, DD) (see Table 1).However, the number of species, as well as the number of threatened species were derived from less than 10% of all land area of the study area.Even if the islands inventoried represent the variation of habitats and different archipelago zones, it is likely that the diversity is much higher than shown in this article.It is well known that fungi do not fruit every year and species occupying narrow ecological niches may have been overlooked.Even after this study the archipelago of the Baltic Sea remains a biogeographically inadequately known part of Finland, partly because of its inaccessibility.
There are 13 old-growth forest indicator species for pine dominated forests in this material and the indicator value is 14 points according to the classification of Kotiranta and Niemelä (1996).This is 40% of indicator species used for pine dominated forests in Finland (Kotiranta and Niemelä 1996).If this is compared to some other large-scale aphyllophoroid fungi inventories in Southern Finland, it is clear that the amount is relatively high.Remote location has saved these areas from large-scale intensive forestry and this may explain why many forests in the archipelago have a high degree of naturalness (P.Kunttu, unpubl.).Many of these old-growth forest species are today common only in the protected areas in northern or eastern Finland.It is obvious that the distribution of these species has earlier covered almost the whole of Finland, but as a result of forceful forestry with large clear-cuts these species can survive nowadays only in some spared small and remote forests here and there, mainly in less inhabited northern Finland.Dispersal capability of some fungal species with specialised resources and habitat requirements may be quite weak and this affects the occurrence of these species in fragmented landscapes (Norros et al. 2012).
It is not possible to compare the number of species with other areas, because inventories in this part of Finland are focused mainly on polypores.Also, areas and inventory methods vary.However, a few examples of studies combining polypores and corticioids exist: from 10 hectares herb-rich forest 109 aphyllophoroid species have been found (Kunttu and Kulju 2009), from the Ekenäs Archipelago National Park 150 aphyllophoroid species were recorded with an indicator value of 10 points (Bonn and Routasuo 1997;Kunttu and Kolehmainen 2011;Pennanen 2013) and one old-growth forest area on southern coast harboured 173 aphyllophoroid species (Kiema and Saarenoksa 2009).Juutilainen et al. (2011) found 133 aphyllophoroid species (mainly from twigs) from 48 small size sample plots in central Finland.The inventories of only polypores yielded 119 species from the Åland Islands (Schigel 2007) (Savola 2006).

ACKNOWLEDGEMENTS
We are very grateful to the following persons who have helped us.Professor Urmas Kõljalg (University of Tartu) and Jorma Pennanen (Karjaa) helped to identify specimens, M.Sc.Timo Kosonen (University of Turku) and Sanna-Mari Kunttu (Metsähallitus, Natural Heritage Services) assisted the author PK during the field work, M.Sc.Jukka Vauras (Åbo Akademi) gave valuable information about his study and Sanna-Mari Kunttu drew the map.Finnish Cultural Foundation, Varsinais-Suomi Regional fund, Nordenskiöld-samfundet i Finland r.f., Societas pro Fauna et Flora Fennica and Ella and Georg Ehrnrooth Foundation are warmly thanked for the financial support to PK's study 2008-2011.

Figure 1 .
Figure 1.Map of the Archipelago Sea and location of the investigated area (black line).

Table 1 .
and 91 Aphyllophoroid fungi of the Archipelago Sea National Park and its surrounding area.

Table 1 .
Continued.Aphyllophorales of the Archipelago Sea National Park, Finland ContinuedKunttu et al. |

Table 1 .
Continued.Aphyllophorales of the Archipelago Sea National Park, Finland ContinuedKunttu et al. |

Table 1 .
Continued.Aphyllophorales of the Archipelago Sea National Park, Finland ContinuedKunttu et al. |

Table 1 .
Continued.Kunttu et al. | Aphyllophorales of the Archipelago Sea National Park, Finland species from Karkali Strict Nature Reserve with indicator value of 10 points