An annotated checklist of macrofungi in broadleaf Mediterranean forests ( NW Italy )

Three different broadleaf Mediterranean forests, each characterized by the dominance of Castanea sativa, Quercus cerris, and Fagus sylvatica, respectively, were intensively surveyed over 3 consecutive years to record a list of macrofungi. A total of 5,065 sporomata and 300 species (seven Ascomycota and 293 Basidiomycota) belonging to 18 orders, 59 families, and 117 genera were recorded. The ecology, community composition, and geographic distribution of the identified species are discussed and new records for Italy are also provided.


Introduction
Fungi are among the most important organisms on Earth, both in terms of a high species richness and their functional roles in aquatic and terrestrial ecosystems.They play a crucial role in the nutrient cycles and establish important pathogenic and/or mutualistic interactions with plants and animals.In the soil system, fungi affect forest ecosystem functions by driving the carbon cycle, decomposing the organic matter, mediating nutrient and water uptake, and maintaining soil structure and forest food webs [1,2].Thus far, our knowledge on fungal diversity is incomplete since only a small fraction (~100,000 spp.) of the estimated (~5.1 million spp.) existing species on Earth has been described [3][4][5].This is due to the cryptic and ephemeral nature of the reproductive structures of macrofungi (named sporomata/fruiting bodies [6]), as well as the need of a wide taxonomical knowledge for species identification and a high field sampling effort [7][8][9][10].
The knowledge of the macrofungal component represents a useful tool for the establishment of priorities for sites of conservation and an indicator of forest perturbations [11,12].It has been widely demonstrated that environmental changes affect the species richness and composition of the macrofungal communities [13,14].
In this study, we report the results achieved by mycological investigations carried out over three consecutive years in three broadleaf Mediterranean forests dominated by Castanea sativa Mill., Quercus cerris L., and Fagus sylvatica L., respectively and located in Northwest Italy (Liguria).The knowledge of macrofungal diversity in Italy is fragmented and several areas and habitats remain unexplored [15][16][17].Liguria, in particular, is characterized by a peculiar geomorphology and climate that allow the coexistence of a great richness and diversity of habitats.Forests cover a remarkable percentage of the whole territory (ca.62%), and broadleaf woods represent the prevalent vegetation type (ca.87%) [18].
The aim of this study was to increase our knowledge of the macrofungal diversity associated with broadleaf Mediterranean forests.Specifically, we intended to: (i) provide a detailed list of species, (ii) provide information on ecology and taxonomy of the recorded species, (iii) estimate the frequency of geographic distribution on the national territory, and (iv) detect uncommon and rare species.

Study area
Three broadleaf forests were selected in Liguria (NW Italy) in the province of Savona (municipality of Sassello) (Fig. 1).Site 1 is located in the loc.Badani (44°27'56" N, 8°28'44" E) and is characterized by a young chestnut coppice of approximately 8,800 m 2 .The altitude ranges from 420 to 450 m a.s.l.The tree layer is dominated by Castanea sativa.A lower frequency of other woody species such as Sorbus torminalis (L.) Crantz and Populus tremula L. occurs in this site.The percentage cover of the shrub layer is very low (7%), whereas the herbaceous species are abundant (15%).The area is under human intervention (i.e., by cutting and thinning) to remove the undergrowth vegetation and facilitate the collection of chestnuts.Site 2, in the loc.La Maddalena (44°30'14" N, 8°29'17" E), is classified as high forest and covers a total area of about 7,500 m 2 with altitude of 340-380 m a.s.l.The whole area is dominated by Quercus cerris.Other woody species, such as S. torminalis and P. tremula, occur with lower frequency in the site.The percentage cover of the shrub layer is very low (5%), whereas the herbaceous layer cover is very high (70%).The forest belongs to the Lathyro montani-Quercetum cerridis (Barbero et Bono, 1971) Ubaldi 1988 association.Site 3, in the loc.Vereira (44°27'3" N, 8°32'42" E), covers a total area of about 10,000 m 2 and it is also classified as high forest.The altitude is 1,000 m a.s.l.The area is dominated by Fagus sylvatica, followed by S. torminalis and P. tremula at lower frequency.The percentage cover of the shrub and herbaceous layer are very low (10% and 7%, respectively).The forest belongs to the Trochiscantho-Fagetum Gentile 1974 association.
Geologically, Site 1 and 3 are characterized by soils developed mainly on calceschists, whereas Site 2 lies in a complex area characterized by four different parent rocks: serpentineschists, calceschists, chlorite-actinolite schists, and conglomerates.The climate is ascribed to the temperate oceanic sub-Mediterranean type for all the three sites [19] with the mean annual temperature of 12°C [from 0°C (min) in January to 25°C (max) in July)].The mean annual rainfall is 912 mm [33 mm (min) in July, 122 mm (max) in October] [20].

Sampling and data collection
Mycological investigations, targeted to epigeous macrofungi, were carried out over 3 consecutive years (2012-2014).Sampling was performed three/four times per month in fall (early September -late November) and in spring (April and June) in 20 circular (4-m radius) plots (60 in total) selected in each study site along line-transects and following a standardized sampling method for macrofungi [21].Each plot was 20 m away from the next one.The total sample area was approximately 1,000 m 2 for each site.
The identified macrofungal species were split into functional groups as described previously [39], based on their primary mode of nutrition: ectomycorrhizal (ECM), soil (humus or litter) decay (SHL), parasitic (P), and wood decay (WD).Further, with reference to national checklists [15,40], a value of geographic distribution was given for each species.Accordingly, all species were split in four classes: widespread (w) -species recorded on more than 65% of Italian territory; common (c) -species recorded on 40-65%; not common (nc) -species recorded on 20-40%; rare (r) -species recorded on less than 20% of Italian territory.With the symbol of asterisk (*) we specified species that are not listed in the available national checklists.

List of the species
Based on the macro-and microscopic examination, the species listed below were identified.For each species the ecology, vegetation of the study site(s), distribution in Italy, and the abundance (i.e., number of ascomata, stromata, or basidiomata) were recorded.
Species repartition into functional groups showed that the ectomycorrhizal fungi (ECM) had the highest number of species (173), followed by the wood decaying species (WD) (69 sp.) and the soil decaying fungi (SHL) (54 sp.).Only four parasites species were recorded (viz.Armillaria mellea, A. tabescens, Tremella foliacea, and T. mesenterica).Overall, despite the differences in the vegetation type, the three sites also showed a similar community composition and trophic ratio.
According to the available data on the geographic distribution of macrofungal species in Italy [15][16][17]40], we found a significant number of widespread (190) and common (83) species.However, it is worth noting that among the collected species, a relevant number are uncommon (10) or rare (10) 6) were found for the first time.

Discussion
The results obtained in this study contribute to improve the knowledge on macrofungal diversity in broadleaf Mediterranean forests.The relevant number of species and abundance of sporomata recorded indicate that these types of forests are favorable habitats for a wide range of macrofungi.In accordance with previous studies [41,42], we can confirm the high macrofungal species richness of Liguria in the Italian territory [15,17,40].The presence of new records and rare species add to the data on their geographic distribution.Specifically, to the best of our knowledge, the aforementioned (see "Results" section) seven species have not been listed in the available checklists of the Italian macrofungi [15,17,40,41,43].Worldwide check-listing studies stated that Alboleptonia sericella has been recorded in South America (e.g., in Brazil [44] and Guyana [45]), in the USA (in California [46]), and in Europe (e.g., in Germany [47] and Poland [48]).Information available on the geographical distribution of Clitocybe herbarum found in Cyprus island (Mediterranean basin) is limited [49].Cortinarius caesiopallescens was collected in Europe (in France) and previous studies highlight the rarity of this species [22][23][24][25][26]50].Similarly, C. helianthemorum, C. olidoamethysteus, and C. ophiopus were collected from France [50][51][52].Finally, the geographical distribution of Entoloma cinchonense has been reported from Korea [53].The few studies available confirmed the rare distribution and number of collections of these seven species, as well as the lack of published data/records from Italy.
Further investigations are needed to define an accurate Italian checklist and to enrich our knowledge on macrofungal biodiversity in the Mediterranean forests.

Fig. 1
Fig. 1 Geographic location of the study sites.

Fig. 3 Fig. 4
Fig. 3 Species repartition into families for each study site.Families of Basidiomycota with only one species were excluded from the graph.
species and seven species (viz.Alboleptonia Species repartition into orders for each study site.