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Jayakumar R.,University of Delhi | Nair K.K.N.,Kerala Forest Research Institute
Tropical Ecology | Year: 2012

The paper aims to evaluate the beta diversity in homogeneous and heterogeneous habitats in tropical forests. Also, the relationship between beta diversity and richness in the rain forests and monsoon forests is elucidated. The study was conducted in a forest landscape of Nilgiri Biosphere Reserve in the Western Ghats of India. The Wilson and Shmida index was used to assess the beta diversity of the angiosperms of the region. Results showed that species richness and beta diversity varied in different vegetation types; in heterogeneous habitats, species turnover was mainly due to habitat restriction, and not dispersal limitation, whereas within a homogeneous habitat beta diversity was dependent on dispersal limitation. Most of the species were restricted to specific habitats; a few species were more adapted to a wide spectrum of climatic conditions. Beta diversity and species richness of rain forests were higher than those of the monsoon forests. © International Society for Tropical Ecology. Source

Kumara H.N.,Salim Ali Center for Ornithology and Natural History | Suganthasakthivel R.,Kerala Forest Research Institute
Tropical Conservation Science | Year: 2011

Petinomys fuscocapillus, Jerdon 1847,Travancore flying squirrel, is known to occur in the forests of India and Sri Lanka. In spite of extensive surveys very few individuals were recorded in the last century. For a better understanding of the possible range of distribution, the present study mapped the potential geographic distribution of the P. fuscocapillus from peninsular India and Sri Lanka. We utilized occurrence records of 32 confirmed sightings of P. fuscocapillus to model the species ́potential geographic distribution by applying an ecological niche modelling (ENM) framework using Genetic Algorithm for Rule set Prediction (GARP). Results indicate that the modeled potential distribution of P. fuscocapillus in India is highly restricted to the narrow strip on western slope of the Western Ghats, and in Sri Lanka the predicted distribution is predominant in the lowlands of wet and intermediate zones. Further, about 88% of the modeled potential distribution range lies outside the protected area network and occupies lowland evergreen, semi-evergreen and its degraded forested stages. The narrow environmental niche of both known and modeled potential distribution and highly susceptible forests with less protection raise the need for conservation efforts and future studies. © Honnavalli Nagaraj Kumara and Ramamoorthy Suganthasakthivel. Source

Sreekanth P.M.,Bangalore City College New Campus | Balasundaran M.,Tropical Institute of Ecological science | Nazeem P.A.,Kerala Agricultural University | Suma T.B.,Kerala Forest Research Institute
Conservation Genetics | Year: 2012

Teak (Tectona grandis L. f.) is one of the most durable timbers in the world that is used for all conceivable purposes. Its widespread use has constrained the distribution of species to small and isolated populations. The genetic structure within and between nine natural teak growing forests of the Western Ghats of India belonging to the states of Kerala, Karnataka and Tamil Nadu was investigated using amplified fragment length polymorphism markers to provide reasoned scientific management practices and conservation measures. The use of ten selective primer combinations on 180 samples (9 populations X 20 trees) resulted in a total of 665 bands of which 99.4 % were polymorphic. Gene diversity index (H) varied from 0.1387 (Barchi) to 0.2449 (Wayanad). The mean gene diversity (HS) was 0.1995 and the total gene diversity (HT) was 0.264. The Southern Western Ghats populations showed higher within population gene diversity. The relative magnitude of genetic differentiation among populations (GST) was 0.244. Positive correlation between genetic and geographical distances was observed. PCoA, UPGMA and STRUCTURE analyses revealed the tendency of the individual trees within a population to align together indicating specific identity of each population. In the UPGMA dendrogram, Nilambur population joined separately with a large cluster in which the other Kerala populations and Tamil Nadu population formed sub clusters indicating a separate identity for Nilambur population among Southern Western Ghats populations. © 2012 Springer Science+Business Media B.V. Source

Kallarackal J.,University of Bayreuth | Kallarackal J.,Kerala Forest Research Institute | Bauer S.N.,University of Bayreuth | Nowak H.,University of Bayreuth | And 2 more authors.
Planta | Year: 2012

Reports about diurnal changes of assimilates in phloem sap are controversial. We determined the diurnal changes of sucrose and amino acid concentrations and fluxes in exudates from cut aphid stylets on tansy leaves (Tanacetum vulgare), and sucrose, amino acid and K+ concentrations and fluxes in bleeding sap of castor bean pedicel (Ricinus communis). Approximately half of the tansy sieve tubes exhibited a diurnal cycle of sucrose concentrations and fluxes in phloem sap. Data from many tansy plants indicated an increased sucrose flux in the phloem during daytime in case of low N-nutrition, not at high N-nutrition. The sucrose concentration in phloem sap of young Ricinus plants changed marginally between day and night, whereas the sucrose flux increased 1.5-fold during daytime (but not in old Ricinus plants). The amino acid concentrations and fluxes in tansy sieve tubes exhibited a similar diurnal cycle as the sucrose concentrations and fluxes, including their dependence on N-nutrition. The amino acid fluxes, but not the concentrations, in phloem sap of Ricinus were higher at daytime. The sucrose/amino acid ratio showed no diurnal cycle neither in tansy nor in Ricinus. The K+-concentrations in phloem sap of Ricinus, but not the K+ fluxes, decreased slightly during daytime and the sucrose/K+-ratio increased. In conclusion, a diurnal cycle was observed in sucrose, amino acid and K+ fluxes, but not necessarily in concentrations of these assimilates. Because of the large variations between different sieve tubes and different plants, the nutrient delivery to sink tissues is not homeostatic over time. © 2012 Springer-Verlag. Source

Sajitha K.L.,Kerala Forest Research Institute | Florence E.J.M.,Kerala Forest Research Institute
Journal of Tropical Forest Science | Year: 2013

An actinomycete isolated from the soil, identified as Streptomyces sp. SA18, was found to be an effective antagonist against the fungus Lasiodiplodia theobromae that caused sapstain on rubberwood. One of the antagonistic factors responsible for this inhibitory effect was identified as chitinase enzyme production, which degraded the chitin of fungal cell wall to N-acetyl D-glucosamine. In the chitin agar plate inoculated with Streptomyces sp. SA18, the dye bound with stable chitin and fluoresced under ultra violet light. On the contrary, chitin-free portions appeared dark indicating degradation of chitin by chitinase enzyme produced by Streptomyces sp. SA18. © Forest Research Institute Malaysia. Source

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