Water-borne hyphomycetes in tree canopies of Kaiga (Western Ghats), India

Naga M Sudheep,Kandikere R Sridhar

doi:10.5586/am.2010.024

Abstract

The canopy samples such as trapped leaf litter, trapped sediment (during summer), stemflow and throughfall (during monsoon) from five common riparian tree species (Artocarpus heterophyllus, Cassia fistula, Ficus recemosa, Syzygium caryophyllatum and Xylia xylocarpa) in Kaiga forest stand of the Western Ghats of southwest India were evaluated for the occurrence of water-borne hyphomycetes. Partially decomposed trapped leaf litter was incubated in bubble chambers followed by filtration to assess conidial output. Sediments accumulated in tree holes or junction of branches were shaken with sterile leaf disks in distilled water followed by incubation of leaf disks in bubble chamber and filtration to find out colonized fungi. Stemflow and throughfall samples were filtered directly to collect free conidia. From five canopy niches, a total of 29 water-borne hyphomycetes were recovered. The species richness was higher in stemflow and throughfall than trapped leaf litter and sediments (14-16 vs. 6-10 species). Although sediments of Syzygium caryophyllatum were acidic (5.1), the conidial output was higher than other tree species. Stemflow and throughfall of Xylea xylocarpa even though alkaline (8.5-8.7) showed higher species richness (6-12 species) as well as conidial load than rest of the tree species. Flagellospora curvula and Triscelophorus acuminatus were common in trapped leaf litter and sediments respectively, while conidia of Anguillospora crassa and A. longissima were frequent in stemflow and throughfall. Diversity of water-borne hyphomycetes was highest in throughfall of Xylea xylocarpa followed by throughfall of Ficus recemosa. Our study reconfirms the occurrence and survival of diverse water-borne hyphomycetes in different niches of riparian tree canopies of the Western Ghats during wet and dry regimes and predicts their possible role in canopy as saprophytes, endophytes and alternation of life cycle between canopy and aquatic habitats.

Highlights

Forest canopies are endowed with a mosaic of flora, fauna and microbes (Nadkarni et al 2001)
Water-borne fungi are known from canopies. They have been reported from the epiphytes, tree holes, trapped leaf litter, stemflow, throughfall and other niches of canopy in temperate and tropical regions (e.g., Ando, Tubaki 1984; Czeczuga, Orłowska 1998a, 1999; Gönczöl, Révay 2006; Sridhar et al 2006; Karamchand, Sridhar 2008, Sridhar 2009; Sridhar, Karamchand 2009)
The mean temperature of stemflow and throughfall ranged between 24.4°C and 25°C respectively

Summary

Introduction

Forest canopies are endowed with a mosaic of flora, fauna and microbes (Nadkarni et al 2001). Water-borne fungi (aquatic and aero-aquatic hyphomycetes) are known from canopies. They have been reported from the epiphytes, tree holes, trapped leaf litter, stemflow, throughfall and other niches of canopy in temperate and tropical regions (e.g., Ando, Tubaki 1984; Czeczuga, Orłowska 1998a, 1999; Gönczöl, Révay 2006; Sridhar et al 2006; Karamchand, Sridhar 2008, Sridhar 2009; Sridhar, Karamchand 2009). About 33 species of fungi encompassing many water-borne hyphomycetes have been reported in rainwater dripping through building roofs in Poland and predicted their survival due to accumulation of sediments on undulating roof surfaces (Czeczuga, Orłowska 1997). About 125 species of water-borne hyphomycetes have been reported from the tree canopies (Sridhar 2009; Karamchand, Sridhar 2009; Sridhar, Karamchand 2009)

Methods

Results

Conclusion