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Canopy science and its relevance in India
Get PDFTropical forest canopies are the least explored regions in the world. The estimate on global species richness
was drastically revised after a short exploration of forest canopies. Yet, it still remains one of the least
understood regions in our biosphere. Many brave researchers in the past have explored these regions with
limited accessing capabilities across the globe and have revealed interesting findings on the behaviour of plants and animals. In recent times canopy science, thanks to hi-tech accessibility, is emerging as a new discipline where more interdisciplinary and large-scale research possibilities are forthcoming; canopy– atmosphere interactions, structural and functional aspects of canopy on biodiversity are a few among them. Forest canopy research can also provide inputs to many global-level processes such as climate change. Here, we review the direction that canopy science has taken in recent times in the tropics and also explore the possibilities of pursuing canopy science more intensively in India
The Common Property Resource Digest
No full textThis issue of the CPR Digest presents an all too rare feature: an CPR Forum catalyzed by IASCP members with an opinion to share. Ajit Menon and Sharachchandra Lele had an idea that they wanted to discuss. They felt that a recent article by Arun Agrawal contained some assumptions about both the nature of institutional success and the values held in common among commons scholars that needed
clarification. They suggested that a CPR Forum would be a great place to hold such a discussion, and we are glad they did. Debates in the Digest are easier and less formal than in journals, so we hope that others who want to air their views on a commons-related topic will
think of the CPR Forum. Arun graciously consented to address their critique, so his response rounds out this short Forum
Properties of Advanced Weathering-Stage Soils in Tropical Forests and Pastures
No full textEffects of tropical forest conversion to nonforest uses greatly affects low-activity soils with substantial variable charge, but quantitative changes are poorly studied. We evaluated forest conversion effects on Ultisols and Oxisols by establishing a spatial comparison study on alluvial fans and terraces in the Rio General Valley of Costa Rica. Soils from pairs of forest and pastures on similar local landforms were sampled to evaluate differences in physical and chemical properties to a depth of 120 cm. In the upper 30 cm, soils under forests had lower bulk densities than under pastures (0.81 vs. 1.04 g cm-3), and soil C under pasture was less than that under forest by about 15.9 ± 10.4 Mg ha-1. Compared with forest soils, those under pastures had a greater soil pHH2O throughout the upper 120 cm (0.44 ± 0.10 pH units). Soil effective cation-exchange capacity (ECEC) was 39 ± 19.9 kmolc ha-1 greater under pastures than under forests, a difference in ECEC that was mainly associated with an additional 19.3 ± 17.7 kmolc ha-1 of exchangeable Ca. Forest clearing and burning followed by conversion reduced soil C moderately but apparently increased the ability of mineral soils to retain exchangeable-cationic nutrients because of increased soil pH. Water-stability of aggregates was less in pastures than under forests (36.5% less for aggregates >2 mm). Reduced soil C was statistically associated with changes in the percentage of water-stable aggregates >0.25 mm (R2 = 0.34, P < 0.05). Our understanding of the effects of land uses on advanced weathering-stage soils would benefit from monitoring studies that directly observe temporal soil changes caused by management
Impact of Firewood Extraction on Tree Structure, Regeneration and Woody Biomass Productivity in a Trekking Corridor of the Sikkim Himalaya
No full textForest cover types, tree distribution pattern, species diversity, net woody biomass productivity, and firewood
extraction rates were studied along a trekking corridor (Yuksam– Dzongri) in Khangchendzonga Biosphere Reserve,
Sikkim, India. For the last 2 decades the area has been
facing immense pressure on its natural resources because of an increase in the numbers of tourists and the lack of effective regulation by park authorities. To assess this situation the study sites were categorized as closed canopy (CC) forest and open canopy (OC) forest (disturbed) at upper forest (UF) and lower forest (LF) sites, on the basis of firewood extraction pressure from the community and tourism enterprises. The results showed significant variations in diversity, richness, structure, productivity,
and regeneration among different canopy types. OC forest showed greater plant diversity than CC forest. Firewood extraction pressure was remarkably greater in the LF near the major settlement than in the UF. Local conservation initiatives and the interventions of an ecotourism project have had visible impacts on firewood use by the community and on tourism enterprises. Although alarming, the rate of woody biomass extraction was nonetheless lower than the annual productivity rate of the stands. Participatory management and compliance by tourism enterprises with a code of conduct on alternative fuel use along the trekking corridor would help promote the conservation and maintenance of biodiversity
Distributions of forest birds and butterflies in the Andaman islands, Bay of Bengal: nested patterns and processes
No full textThe distributional patterns of forest birds and butterflies in the Andaman islands, an oceanic chain located off SE Asia, were tested for nestedness. Both taxa were highly nested. Nestedness could be due to colonization or extinction processes, area or distance effects or nestedness of habitats. Nestedness in forest bird distributions were strongly influenced by area and habitat related factors. Habitats were significantly
nested in all three island groups, however most strongly for the North Andamans. However forest bird distributions in the North Andamans, as indicated by row order
in the packed matrix, was not correlated with habitat diversity, suggesting that habitat related factors alone cannot account for these patterns. Other causal influences could be passive sampling, where common and abundant species and habitats are more likely to have a widespread distribution than rare species and habitats. The nested subset pattern seen in two unrelated taxa suggests that the Andamans are extinction dominated and that the protection of forests on large islands is critical for the conservation of its biodiversity
First report of Micrixalus nudis (Amphibia: Ranidae) from Karnataka, India
Get PDFThe Western Ghats is one of the “hotspots” of biological diversity with high endemicity (Myers, et. al., 2000). About 123 species of amphibians (60% of the total species count for India) are found in the Western Ghats of which 93 species are endemic (Daniels, 1992; 1997a; Molur and Walker, 1998
Report Assessing Biodiversity from Space: an Example from the Western Ghats, India
No full textWe demonstrate for the first time the potential use of satellite imagery to characterize areas of high and low species richness of trees in tropical forests. Our studies, conducted in the Biligiri Rangaswamy hills in the Western Ghats, India, show a high positive correlation between species richness and the Normalized Difference Vegetation Index (NDVI), which is an index of green biomass. We discuss the application of NDVI values for biodiversity assessment and monitoring, as well as for conservation planning. The NDVI is a rough measure of green biomass
Nutrient Use Efficiency in Three Fast-Growing Tropical Trees
No full textWe measured nutrient use efficiency (NPP/nutrient uptake) in three species of tropical trees, Hyeronima alchorneoides, Cedrela odorata, and Cordia alliodora. We tested the prediction that on fertile soils species with very different biomass and nutrient allocation and turnover would converge on a common value of nutrient use efficiency. Due to high soil fertility, nutrient use efficiencies of the species studied were low (95–150 and 433–962 for N and P use efficiency, respectively). Nutrient use efficiency was examined in terms of its components, nutrient productivity and the mean residence time of nutrients. Although the species converged on the same nitrogen (but not phosphorus) use efficiency,
differences in nutrient productivity and nutrient residence time may confer varying abilities to deal with
nitrogen limitation. A combination of high nutrient productivity and longer nutrient retention (e.g., Hyeronima) signals an ability to prosper on infertile sites, whereas high nutrient productivity in the absence of long nutrient retention (e.g., Cedrela) indicates a capacity for high productivity, but only on fertile soil. Nutrient use efficiency and its components help explain species’ distributions in natural communities and can be important criteria in selecting perennial plants for human use. For. Sci. 48(4):662–672
Response of wet forest butterflies to selective logging in Kalakad–Mundanthurai Tiger Reserve: Implications for conservation
Get PDFThe butterfly fauna of an unlogged wet evergreen site
in Kalakad–Mundanthurai Tiger Reserve was compared with that of an adjoining 30-year-old selectively logged site. Comparison of the vegetation structure of both sites showed that the canopy was less contiguous and the ground cover was higher in the logged site. Species richness, abundance, and diversity of butterflies were higher in the selectively logged site. Species abundance in both forests types fitted log series distribution, which indicates that only a small portion of the assemblage occur in high abundance. Examination of habitat usage by the butterflies showed that the logged forest harbored a greater number of ubiquitous species along with the wet forest assemblage. Few species like Idea malabarica showed restraint in logged site, while there was a release of few other species in logged site. Implications of these results for butterfly conservation are discussed
Interactions between social bees and their foodplants in a rainforest canopy of Western Ghats, India
No full textIntegrating the phenology of pollinators and their food plants is crucial to understand pollination guilds. In the tropics, studies on the phenology of the trees and of pollinating vectors such as bees have mostly been carried out independent of each other. This study, carried out at a wet evergreen forest of Kakachi, in Southern Western Ghats, integrates the phenology of two social bee species Apis dorsata and Apis cerana with their canopy and sub-canopy food plants. The two bee species are the only ones that are active on the canopy of this forest and visit the understorey plants occasionally (Davidar et a1., unpublished). Unlike other tropical forests, solitary bees are distinctly absent in this forest canopy, and therefore the two bee species playa major role in the pollination of a number of tree species in the forest