The canal represents a very characteristic and new habitat for freshwater hyphomycetes, It is a massive body of water with little fluctuation in the physico-chemical properties of water. The only variable characteristics appear to be the annual temporal changes, between 10 and 26 oC ,and the biomass content of water. The gradual build up of substratum is observable because of the annual clearing during the closure of canal in January.
A total of 67 species of freshwater hyphomycetes was observed in canal water during a study of two years using three possible techniques. These included water filtration, random collection of submerged fallen leaves and immersion of leaves of some known tree species as baits. Thirty-seven unknown species of hyphomycetes were recorded. About 13 species could not be placed in the known genera In addition to the undescribed species, Articulospora proliferata, Mycocentrospora iqbalii, sporidesmium ensiforme and Sympodiocladium frondosum are new records from this sub-tropical habitat in Pakistan.
Some substrate preferences were observed by different species of canal water hyphomycetes on different bait leaves under a similar temperature regime. Some of these particular associations included Flagellospora penicillioides nad Lunulospora curvula on Dalbergia sissoo, F. lpenicillioides nad Triscelophorus monosporus on Eucalyptus camaldulensis, Clavaruopsis aquatica and Lunulospora curvula on Populus enramericana and dimorphospora foliicola nad T. marchalianum on salix babyloica.
Three seasonal associations were observed using the Bruaun-Blanquet approach of community formation. Tetracladietum marchalianae was detected in February and March, characterized by very little substratum and low temperature. Flagello-Lunulosporetum curvulae was detected during April upto August, the period with the highest temperature, representing a true summer assemblage. Lunulosporetum curvulae was observed during September to December, representing a low temperature regime associated with leaf fall. The maximum number of species was detected in the Association Lunulosporetum curvulae.
The Associations formed using different techniques in this habitat were almost similar. The association formed by water filtration, submerged fallen leaves and on bait leaves of Populus euramericana was Lunulosporetum curvulae. However, on bait leaves of Dalbergia sissoo, lthe Association Lunulo-Flagellosporetum penicillioides was formed. On bait leaves of Eucalyptus camaldulensis and Salix babylonica, different associations namely, Flagellosporetum penicillioide and Tetracladietum marchalianae were formed resplectively.
The colonization patternon different bait leaves imn the different associations indicated some typical early colonizers to be Articulospora proliferate, Lemonniera aquatca, L. centrosphaera, Tetracladium marchaliaunm and unknown species I. Among the typical late colonizers, anguillospora longissima, Anguillospora sp.A, Campylospora chaetocladia, Clavalriopsis aquatica, Pyramidospora casuarinae and Triscelophorus monosporus were recorded.
A total of 98 species of freshwater hyphomycetes were observed in the Karakorum Range. Heliscus lugdunensis, Lemonniera aquatica nad Tricladium curvisporum were the most dominant species with a wide ecological amplitude, Thirty-three known and 65 unknown species were observed, out of which 17 species could not be placed anywhere in the known genera.
The reason for such a large number of unknown species is that a majority of them were detected in artificial foam samples. The maximum number of species was always observed in the artificial foam in comparison to all other techniques. A greater number of species was detected using all possible techniques giving a true picture of the community at a given site.
The longitudinal distribution of freshwater hyphomycetes was most influenced by the substrate materials. Near the glaciers, or at the origin of streams, only those species were present which commonly colonize woody substrata. The diversity of species was higher at sites with thick riparian vegetation. Water chemistry did not change much and did not influence the community.
The spora in the lakes always reflected the presence or absence of substrata and the turbulance created in water . The species composition was always poor on the shore of lakes except in those where substratum was available and water was turbulant. The inlet streams to the lakes were always richer in species diversity in comparison to outlet streams indicating sedimentation of conidia.