PhD

The study was carried out with the objectives to find out the diversity, distributional status and ecology of polypores in forest ecosystems of Kerala. The representative sample plots of major forest types on either side of the Palakkad gap were selected in order to get a good sampling to cover northern, central and southern regions of Kerala and all the major forest ecosystems viz., evergreen, semi-evergreen, moist deciduous, dry deciduous and shola forest. Three permanent sample plots of 100 m×100 m with subplots of 10 x 10 m were established in three different locations in each ecosystem (5 in south of Palakkad gap and 5 in north of Palakkad gap). Shendurney Wildlife Sanctuary and Periya forest range of North Wayanad forest division were selected to represent evergreen forest. Semi-evergreen forest plot was taken in From Neyyar Wildlife Sanctuary and Aralam Wildlife Sanctuary. The moist deciduous forest samplots were taken from Peechi-Vazhani Wildlife Sanctuary and Wayanad Wildlife Sanctuary. The dry deciduous forest sample plot were taken in Walayar forest range and Marayoor sandal forest. Eravikulam National Park and Brahmagiri shola of North Wayanad division were selected to locate sample plots of shola forest. Apart from the plot based sampling, opportunistic sampling method was also adopted to maximize the documentation of polypore fungal diversity and distribution. As part of opportunistic sampling, all the National Parks and Wildlife Sanctuaries were visited. The polypore collection was carried out during the southwest monsoon (June to September) and north-east monsoon (October to December) from the sample plots. Additionally, labelling, rot character identification, photography, recording macromorphological characters and details of substratum were also made on the illustrated data sheet. All the logs and branches ≥ 20 cm diameter were enumerated using standard equipments. The decay stage of the logs was determined according to a 5-grade scale (based on decay classification system of Pyle and Brown, 1998). An attempt has also been made to find out the effect of substrate features like diameter, type and decay class on the diversity and abundance of polypores. Various polypores associations was worked out along with the different phytosociological indicators like density, frequency, abundance, Simpson’s Index and Shannon-Weiner Index. All the trees in the sample plots (3x10 of 100 x 100) were identified and documented (both host and non host trees).371 Ninety five polypore species in fourty nine genera belonging to eight families were documented. The Polyporaceae was the dominant family with 42 species followed by Hymenochaetaceae (31), Fomitopsidaceae (6) and Meruliaceae (5). Meripilaceae and Ganodermataceae made their presence with 4 species each. The family Schizoporaceae was represented by 2 species. Only one species was reported from the family Phanerochaetaceae. Among the polypores documented, 64 species were annuals and 31 were perennials. While analyzing the rot characteristics of the recorded polypores, it was found that the white rot polypores have notable dominance over brown rot polypores. Of 95 species analyzed, 88 polypores were white rotters and only 7 species were brown rotters. An identification key was developed for the polypores documented from forest ecosystems of Kerala based on the micro and macro morphological features. During the present study, 14 species were found to be new records from Western Ghats and one species is reported for the first time from India. These species have been described based on the macro-morphology and micro-morphology. In evergreen forest at Shendurney Wildlife Sanctuary, Simpson’s Index of diversity was observed to be the highest (0.965) followed by evergreen forest of Periya Forest Range (0.958) and semi-evergreen forest at Aralam Wildlife Sanctuary (0.957). The lowest Simpson’s Index was recorded at dry deciduous forest at Marayoor and Walayar with 0.873 and 0.916 respectively. The shola forest at Eravikulam National Park and Brahmagiri was also recorded with low polypore diversity with Simpson’s Index 0.921 and 0.923 respectively. Shendurney Wildlife Sanctuary showed higher Shanon-Wiener Index value (3.637) followed by evergreen forest of Periya Forest Range (3.458) and semi-evergreen forest at Aralam Wildlife Sanctuary (3.354). The Margalef Richness Index was found to be highest in wet evergreen forest at Shendurney Wildlife Sanctuary (5.747) while it was 1.798 in dry deciduous forest at Marayoor. The evenness in distribution of polypores was observed to be highest in evergreen forest at Shendurney Wildlife Sanctuary and semi-evergreen forest at Neyyar Wildlife Sanctuary with Pielou's Evenness Index 0.908 and 0.905 respectively. The shola forest at Eravikulam National Park and Brahmagiri shola showed more Berger-Parker Dominance Index value 0.238 and 0.194 respectively. The lowest Berger-Parker Dominance Index value (0.076) was recorded in evergreen forest at Shendurney Wildlife Sanctuary. Sorenson’s Similarity Index was worked out to find the similarity of polypore community in different forest ecosystems of Kerala. The similarity between polypore community372 of each forest ecosystems in either side of Palakkad gap was found out. The similarity between each forest types on either side of Palakkad gap found to be more or less uniform (above 0.75) except the dry deciduous forest at Marayoor and Walayar (0.37). The overall similarity of forest on either side of Palakkad gap is found to be much higher (0.918) The influence of altitudinal variation in the distribution pattern of polypores in different forest ecosystems of Kerala were analyzed based on their occurrence along different altitudinal gradients. In all forest types the diversity and richness is decreasing along the altitude. The evenness of polypore is decreasing along the altitude in all forest types of Kerala. The dominance is increasing along the altitude in all forest types A total of 306 tree species belonging to 68 families were identified to occur in the selected sample plots and out of this, 168 species under 51 families were host species. Leguminosae and Lauraceae contributed 18 and 13 species respectively and they represented the major host families followed by Malvaceae (8), Meliaceae (8), Phyllanthaceae (8), Myrtaceae (7), Clusiaceae (6), Moraceae (6), Rubiaceae (6) and Rutaceae (6). Most of the species were host generalist and more or less evenly distributed among the host tree species. Among the substrate types, maximum polypore occurrence was observed on logs followed by branch/twig and snag while, living trees supported only few polypores in all forest ecosystems. Decay class association of polypores showed that the intermediate decay stages harboured the maximum in terms of number of species, number of fruitbodies and frequency of occurrence. The conceptual framework on primary ecological strategy revealed that polypores exhibits ruderal, combative and stress tolerant behaviours. The polypores documented from forest ecosystems of Kerala was classified into ruderal, combative and stress tolerant categories.