首页分享尼泊尔中央喜马拉雅地区橡树主导森林中的菌耳真菌的生态学特征与多样性

尼泊尔中央喜马拉雅地区橡树主导森林中的菌耳真菌的生态学特征与多样性

来源：花匠小妙招时间：2025-09-30 10:15

1 Introduction

Bracket fungi are a group of fungi that grow on the trunks of dead, dying and sometimes living trees. They produce woody, bracket-shaped fruiting bodies with pores or tubes on the underside, which release spores for reproduction (Ghobad-Nejhad and Bernicchia, 2019; Runnel et al., 2021). Bracket fungi are also known as polypore or shelf fungi, and they belong to a diverse group (Polyporales) of basidiomycetes. They are important agents of wood decay, breaking down lignin and cellulose in the wood and releasing nutrients into the soil. They play an important role in nutrient dynamics and energy transformation in forest ecosystems (Woodward and Boddy, 2008). Some bracket fungi are agents of trunk and root rots in woody plants, which can weaken and damage the trees. However, some bracket fungi can also form mycorrhiza with trees, which is a beneficial association that enhances the nutrient uptake and resistance of the plants (Nilsson et al., 2006; Jaranilla et al., 2021). Bracket fungi also create habitats and resources for various invertebrates, such as spiders, mites, pseudoscorpions, insects and collembolans. The diversity of bracket fungi and their associated invertebrates depends on factors such as the degree of decay, the host tree species, the environmental conditions and the spatial scale (Gdula et al., 2021).

Bracket fungi have been used in traditional medicine for centuries, especially in Asia, where some species are considered to have anti-inflammatory, anti-tumor and immunomodulatory properties (Devkota, 2008; Khastini et al., 2018; Badalyan et al., 2019; Elkhateeb et al., 2020; Khadka and Aryal, 2020; Song et al., 2022). They are also being studied for their potential applications in bioremediation, biofuel production and bio-pulping (Taha et al., 2020; Kumar and Dwivedi, 2021).

Orders like Polyporales, Hymenochaetales, Gloeophyllales, Agaricales, Russulales, etc. are examples of bracket fungus. Among them, the varied group of fungus known as Polypores (Order: Polyporales) may be important in terms of morphology, genetics, physiology, and ecology. Given that most species do not share many characteristics, the group as a whole is highly varied. It is a significant category of fungi, with over 30000 species (Webster and Weber, 2007). In Nepal, 21743 species of mushrooms have been estimated, although only 1291 species have been studied to date (Devkota and Aryal, 2020). While Blanco et al. (1997) reported a 1:3.1 relationship between plants and mushrooms in pine-oak forests, Blackwell (2011) asserts that there is a widespread 1:6 ratio between plants and fungus. Though a wide range of research is still inadequate, attention has been drawn in recent years to the caterpillar fungus and a few significant edible species in wild macrofungal studies in Nepal (Devkota and Aryal, 2020). So, this work is designed to explore the overlooked bracket fungi diversity with their ecological condition in the oak dominated forests from middle mountain of central Nepal.

2 Materials and methods

2.1 Study sites

The research work was conducted in mid hills region of Bagmati province. Two oak dominated forests (managed by community forest user groups) located in Kathmandu and Makawanpur districts were selected for the study of bracket fungi (Figure 1; Table 1). It lies in temperate climatic zone of middle mountain range in central Nepal. Winters are generally cold with snowfall, while summers are warm with frequent rain shower in both study sites. According to nearest weather station (Thankot station: 27°36'15''N, 85°05'31''E for Gumalchoki Community Forest and Daman station: 27°41'17''N, 85°13'16''E for Karnabhumi Community Forest), the average annual temperature and average annual precipitation were 10.98 ℃ and 1559.25 mm for Gumalchoki Community Forest) while it was 11.5 ℃ and 1781 mm for Karnabhumi Community Forest respectively. The vegetation was dominated by Quercus sp such as Q. semecaprifolia, Q. glauca, Q. lanata whereas Lyonia ovalifolia, Rhododendron arboreum, Lindera pulcherrima and Pinus wallichiana were some associated species.

Figure 1 Study sites in Karnabhumi CF and Gumalchoki CF from Makawanpur and Kathmandu districts of Bagmati Province, central Nepal

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Table 1 Locations and bracket fungi samples collection time in two research sites in mid hills of Nepal S.N. Research sites Latitude/Longitude Altitude (m) Collection year 1. Gumalchoki Community Forest (GCF), Chandragiri, Kathmandu District 27°39'0.3''N/85°15'35.7''E 2530 2017, 2020, 2021 2. Karnabhumi Community Forest (KCF), Simbhanjyang, Makawanpur District 27°35'41.9''N/85°04'56.0''E 2500 2018, 2021, 2022

2.2 Collection, identification and preservation of bracket fungi

The study was conducted with regular field visits over a six-year period (2017-2022) during the wet season and dry season as well. Samples of bracket fungi were collected from the five study sites of Karnabhumi Community Forest (GCF), Makawanpur and four sites of Gumalchoki Community Forest (KCF), Kathmandu. A method of opportunistic sampling (Mueller et al., 2004) was used, and specimens were collected from the study site. With the aid of a knife, the fruiting bodies were collected after spotting a colony or a single species of mushroom. Their habitat characteristics and frequency of occurrence were noted. The samples were photographed, both in their natural substrate and in reference of scale or coin. Then the samples were collected, labeled, and stored in the polythene jar. According to their characteristics, they were then identified with the help of standard literatures (Pacioni, 1985; Adhikari, 2014; Desjardin et al., 2015; Bala, 2023). All the collected sporocarps were then air-dried at 40-50 ℃ using hair dryer and electric fan heater for long term preservation as herbarium specimens. They were then transferred into the airtight container with naphthalene ball in it and labeled (Drábková, 2014). All herbarium specimens were deposited in the ASCOL Herbarium, Department of Botany, Amrit Campus (Tribhuvan University), Kathmandu, Nepal.

2.3 Data analysis

Richness of macrofungal species (bracket fungi) was determined as the total number of species observed in each study site. Other indices of alpha diversity were calculated according to the following formulas. Simpson Index of Diversity was calculated as suggested by Simpson (1949).

Simpson Index of Diversity=1-D

(1)

(2)

where, n is total number of a particular macrofungal species (bracket fungi) and N is total number of all species. The summation variable is the proportions of individuals of each species relative to the total number of individuals.

Shannon-Wiener Diversity Index for mushroom was calculated as suggested by Shannon and Weaver (1949).

H = -Σ(n/N)×ln(n/N)

(3)

where, H is Shannon-Wiener Diversity Index; N is total number of individuals of all the species; n = total number of individuals of a particular species.

The evenness component of dominance was calculated using the Pielou index (Pielou, 1969):

E=H/lnN

(4)

where, E is the Pielou Index; H is Shannon-Wiener Diversity Index, N is the number of species of bracket fungi.

Margalef’s Index (Margalef, 1973) of species richness was calculated as:

(5)

where, Dm is Margalef’s Index of species richness; n is the total number of species of bracket fungi observed; N is total number of individual counts of bracket fungi.

3 Results

A total of 26 species of bracket fungi belonging to 17 genera spread over eight families of three orders were identified from study sites (Table 2, Figure 2). Thirteen species of bracket fungi were found in both GCF and KCF. Meanwhile five and eight species were only found in GCF and KCF respectively (Figure 3, Table 2). Polyporales was the largest order with 19 species and was followed by Hymenochaetales and Russulales with five and two species bracket fungi respectively (Table 2, Figure 3). Polyporales (11 species in GCF and 16 species in KCF) was the largest order in both sites, GCF and KCF, followed by Hymenochaetales (five species in GCF and two species in KCF) and Russulales (two species in both sites) (Figure 4).

Table 2 Diversity, distribution and details of bracket fungi in Oak dominated forests of Nepal, central Himalaya. S.N. Species of bracket fungi Sites Habitat Ecology Edibility Common/Local name Order: Hymenochaetales
Family: Hymenochaetaceae 1 Coltricia cinnamomea (Jacq.) Murrill GCF, KCF Fallen branches Mycorrhizal/ Saprobic Inedible Cinnamon cap 2 Coltricia perennis (L.) Murrill GCF Soil Saprobic Inedible Tiger’s eye 3 Hymenochaete rubiginosa (Dicks.) Lév. GCF, KCF Dead trunk Saprobic Inedible Oak curtain crust 4 Inonotus hispidus (Bull.) P. Karst. GCF, KCF Living trunk Parasitic Inedible Shaggy bracket 5 Phellinus igniarius (L.) Quél GCF Dead/Living trunk Saprobic/Parasitic Inedible Willow bracket Order: Polyporales
Family: Fomitopsidaceae 6 Daedalea quercina (L.) Pers. GCF Dead trunk Saprobic Inedible Oak mazegill 7 Fomitopsis betulina (Bull.) B.K.Cui, M.L.Han & Y.C.Dai KCF Living trunk Parasitic Inedible Birch polypore 8 Fomitopsis pinicola (Sw) P. Karst. GCF, KCF Dead trunk Saprobic Inedible Red-banded polypore 9 Laetiporus sulphureus (Bull.) Murrill KCF Dead/Living trunk Saprobic/Parasitic Edible/Medicinal Sulphur polypore/ Rato chyau 10 Phaeolus schweinitzii (Fr.) Pat. GCF Living trunk Parasitic Inedible Dyer’s mazegill Family: Ganodermataceae 11 Ganoderma lucidum (Curtis) P. Karst. GCF, KCF Dead/Living trunk Saprobic/Parasitic Edible/Medicinal Lacquered bracket/Rato chyau 12 Ganoderma sessile Murrill KCF Dead/Living trunk Saprobic/Parasitic Inedible -- Family: Irpicaceae 13 Byssomerulius corium (Pers.) Parmasto KCF Fallen branches Saprobic Unknown -- Family: Meruliaceae 14 Phlebia tremellosa (Schrad.) Nakasone & Burds GCF, KCF Fallen branches Saprobic Inedible Jelly rot Family: Polyporaceae 15 Daedaleopsis confragosa (Bolton) J. Schröt. GCF, KCF Living trunk Parasitic Inedible Blushing bracket 16 Microporus affinis (Blume & T. Nees) Kuntze GCF, KCF Fallen branches Saprobic Unknown -- 17 Microporus xanthopus (Fr.) Kuntze GCF, KCF Fallen branches Saprobic Unknown Yellow-stemmed micropore 18 Pycnoporus cinnabarinus (Jacq.) P. Karst GCF, KCF Fallen branches Saprobic Inedible Cinnabar bracket 19 Trametes elegans (Spreng.) Fr. GCF Fallen branches Saprobic Inedible White maze polypore 20 Trametes gibbosa (Pers.) Fr. KCF Fallen branches Saprobic Inedible Lumpy bracket 21 Trametes pubescens (Schumach.) Pilát KCF Fallen branches Saprobic Inedible -- 22 Trametes versicolor (L.) Lloyd. GCF, KCF Fallen branches Saprobic Inedible Turkey-tail 23 Tyromyces chioneus (Fr.) P.Karst. KCF Fallen branches Saprobic Inedible White cheese polypore Family: Steccherinaceae 24 Flabellophora superposita (Berk.) G.Cunn. KCF Fallen branches Saprobic Inedible -- Order: Russulales
Family: Stereaceae 25 Stereum hirsutum (Willd.) Pers GCF, KCF Dead/Living trunk Saprobic/Parasitic Inedible Hairy curtain crust 26 Stereum rugosum Pers. GCF, KCF Dead/Living trunk Saprobic/Parasitic Unknown Bleeding broadleaf crust

Figure 2 Photographs of bracket fungi reported in oak dominated forests of Nepal, central Himalaya

Note: 1. Byssomerulius corium; 2. Coltricia cinnamomea; 3. Coltricia perennis; 4. Daedaleopsis confragosa; 5. Flabellophora superposita; 6. Ganoderma lucidum; 7. Ganoderma sessile; 8. Fomitopsis betulina; 9. Hymenochaete rubiginosa; 10. Microporus affinis; 11. Microporus xanthopus; 12. Phaeolus schweinitzii; 13. Phellinus igniarius; 14. Phlebia tremellosa; 15. Pycnoporus cinnabarinus; 16. Stereum hirsutum; 17. Stereum rugosum; 18. Trametes elegans; 19. Trametes gibbosa; 20. Trametes pubescens; 21. Trametes versicolor; 22. Tyromyces chioneus; 23. Daedalea quercina; 24. Fomitopsis pinicola; 25. Laetiporus sulphureus; 26. Inonotus hispidus.

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Figure 3 Venn diagram showing the number of bracket fungi in two oak dominated forests (GCF and KCF) of Nepal, central Himalaya

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Figure 4 Diversity of bracket fungi orders in Oak dominated Forest Nepal, central Himalaya

Note: Number of species in the Orders represents the overall species number of bracket fungi in both Oak dominated forests.

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The most represented family was Polyporaceae (KCF, 8 species and GCF, 6 species) in Oak Forest of both study sites. Other important macrofungal families were Hymenochaetaceae (KCF, 3 species and GCF, 5 species), Fomitopsidaceae (3 species in each site), Stereaceae (2 species in each site) and Meruliaceae (1 species in each site). Families such as Irpicaceae and Steccherinaceae were represented by single species in KCF only whereas the Ganodermataceae was represented by 2 species and 1 species in KCF and GCF respectively (Figure 4).

Genus Trametes (4 species) was found to be dominating in oak forest of KCF which was followed by Fomitopsis, Ganoderma, Microporus and Stereum with two species. In Case of oak dominated forest of GCF Trametes, Microporus, Sterreum, Coltricia were contributing with 2 species of bracket fungi. Byssomerulius, Flabellophora were Laetiporus only reported in KCF whereas Daedalea, Phaeolus and Phellinus were only reported from oak forest of GCF. Meanwhile, Daedaleopsis, Hymenochaete, Inonotus, Phlebia and Pycnoporus were contributing with single species in oak dominated forests of both sites (Table 2).

Diversity of biological species can be measured using a variety of parameters. The two most important ones are species abundance and species richness. In the current study, the diversity of the bracket fungi was examined in Oak dominated forests from two different community forest. Oak dominated forest of KCF recorded the higher species richness (21 species and 6.12 Margalef’s Index value) than in the Oak dominated forest of GCF (18 species, 5.22 Margalef’s Index value). However, Simpson’s Diversity Index (1-D), Shannon-Wienner Diversity Index (H) and Pielou index (Evenness) were recorded higher in Oak dominated forest of GCF (0.26, 0.53 and 0.078 respectively) than in KCF (0.17, 0.35 and 0.053 respectively). Both sites were recorded with higher inedible bracket fungi. Two species of medicinal shelf fungi (bracket fungi) were recorded from KCF while this was single from GCF. Regarding the ecology of mushroom, most of the species were saprobic in both sites. Majority of the mushroom were recorded growing in fallen branches in both sites which was followed by living trunk and dead trunk (Table 3).

Table 3 Macrofungal taxa, species richness, diversity indices, edibility, ecological role and habitat diversity of bracket fungi species in oak forest of different community forest, central Nepal Variable GCF KCF Diversity indices Species richness 18 21 Shannon-Wiener Index (H) 0.26 0.17 Simpson Index of Diversity (1-D) 0.53 0.35 Margalef’s Index (Dm) 5.22 6.12 Pielou Index (E) 0.078 0.053 Edibility Inedible 16 15 Unknown 1 4 Edible/Medicinal 1 2 Ecology Saprobic 11 12 Saprobic/Parasitic 3 5 Parasitic 4 3 Mycorrhizal/Saprobic 0 1 Habitat Fallen branches 7 11 Living trunk 3 3 Dead trunk 3 2 Dead/Living trunk 4 5 Soil 1 0

4 Discussion

Oak forest provides diverse range of forest ecosystem services (Dorji et al., 2019), about 800-1000 species of mosses, lichens, mycorrhizal mushrooms, wood decomposing mushrooms and invertebrates are restricted to oak (Danell, 2001). The growth and development of macrofungi are significantly influenced by a number of ecological parameters, including geographic location, temperature, relative humidity, light, and nearby vegetation (Bhandari and Jha, 2017; Joshi et al., 2022). Oak dominated forest of KCF has the higher species richness than in that of GCF. This was presumably caused by the fact that there is less anthropogenic disturbance in KCF as it is located in the rural area. A greater number of litter-decomposing and wood-rotting mushrooms can colonize an area when there is less human interference, favorable climate, vegetation, and availability of degradable materials in greater quantities (Baral et al. 2015; Bhandari and Jha, 2017).

According to Kalntremtziou et al. (2023), basidiomycetes produce a variety of lignocellulolytic enzymes, which are crucial for the breakdown of organic materials. Temperate forests may have accumulated more substrate due to rapid decomposition rates (Ramos et al., 2021) and the higher number of Basidiomycota-related mycorrhizal species found on soils with decomposing litter (Mueller et al., 2007). This may have contributed to the higher species diversity in Basidiomycota as resulted in this research. The order Polyporales and family Polyporaceae were found to be the most dominating taxa among 26 species of bracket fungi which is similar to the findings of Mueller et al. (2006) in Costa Rican Quercus-dominated forests. Abiev et al. (2022) and O’Hanlon and Harrington (2012) were also reported the higher species from Polyporaceae in Oak forests of Kazakhstan and Ireland respectively. The species composition of bracket fungi in current study is similar with that of Pine forests (Bhandari and Jha, 2017) as both pine and oak trees are symbiotically associated with similar ectomycorrhizal fungi (Trocha et al., 2012).

The occurrence of saprophytic bracket fungi (e.g., Coltricia perennis, Hymenochaete rubiginosa, Daedalea quercina, Fomitopsis pinicola, Byssomerulius corium etc.) was higher than mycorrhizal and parasitic in the oak dominated forests of both study areas. Such Saprophytic bracket fungi were found mostly growing on fallen branches of oak trees which is in accordance with Rostamian (2013) and Jaranilla et al. (2021). This confirms their role in primary decomposition of wood and subsequent nutrient cycling. In both forests, some parasitic incidences were reported which were caused by polypores such as Inonotus hispidus, Phellinus igniarius, Fomitopsis betulina, Laetiporus sulphureus, Phaeolus schweinitzii, Ganoderma lucidum, Ganoderma sessile and Daedaleopsis confragosa. Similar instances were inferred by Pandey et al. (2006) and Devkota (2008) in Nepal, Garibay-Orijel et al. (2009) in Mexico, Semwal et al. (2014) in India, Runnel et al. (2021) in Estonia and Jaranilla et al. (2021) in Philippines. Coltricia cinnamomea, a single mycorrhizal bracket fungus in oaks (Kim et al., 2003), was found in the current study, however oaks rely on their interactions with ectomycorrhizal fungi for seedling establishment to survival (Garibay-Orijel et al., 2020). The ectomycorrhizal fungus uses the host plant’s photosynthates to produce their own, and they also give the plant extra nutrients and water. These fungi also provide resilience to stresses (Hachani et al., 2020), promote host plant growth (Wang et al., 2022), and provide protection against pathogenic infections.

According to local inhabitants Laetiporus sulphureus have been collected in large quantity for the food and medicinal purposes which is in line with the previous literature (Pandey et al., 2006; Khadka and Aryal, 2020; Adhikari et al., 2024). Only three medicinal bracket fungi were collected from Oak dominated forests of both study sites (Table 2). These are Ganoderma lucidum, Laetiporus sulphureus and Pycnoporus cinnabarinus and which have many medicinal values such as anti-oxidant, anti-aging, anti-cancer, anti-bacterial, immunostimulatory, anti-viral, anti-allergenic anti-inflammatory, hepatoprotective, anti-radiative, psychoactive, free radical scavenger and other effects (Joshi and Joshi, 1999; Bulam et al., 2019; Suansia and John, 2021; Thapa et al., 2022; Adhikari et al., 2024).

Bracket fungi are not only important ecologically due to their decomposing wood by breaking down cellulose and lignin (Datry et al., 2018), they are the microhabitats for many mycophagous insect communities (Kadowaki, 2010; Gdula et al., 2021). A number of species of bracket fungi collected during this study have not yet been identified, and they are continuously being monitored. A six-year survey might be not sufficient to show the diversity of bracket fungi in oak dominated forests. Because certain species may not have produced sporophores at the time of field visit. Thus, our understanding of species richness and community composition bracket fungi will surely be improved by sampling over longer periods of time and at more locations.

5 Conclusions

Based on result, fair diversity of bracket fungi in oak dominated forests of the study sites. In total, 26 species of bracket fungi from 17 genera, eight families and three orders were studied. Polyporales was the obvious dominating orders of the bracket fungi. The majority of the bracket fungi were saprophytic in ecology which indicates of good diversity of decomposition and nutrient cycling- regulating species. Furthermore, this study will serve as a baseline database of bracket fungi in oak dominated forests from middle mountain of Nepal.

Acknowledgements

Prof. Dr. Mukesh Kumar Chettri and Asst. Prof. Krishna Prasad Sharma provided invaluable assistance to the author in order to complete this research project. Dr. Sujan Balami and Mr. Bhawani Bhandari provided commendable field support. I am also grateful to the members of GCF and KCF who gave me permission to conduct this research on bracket fungi and provided native information about the gathered mushrooms.

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