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Studies on Insect Community Responses to Habitat Restoration Efforts in Tropical Forests of Western Ghats
Get PDFEco-restoration is undertaken as an ameliorating activity to mitigate widespread
degradation of ecosystem functions and services as large-scale degradation and
biodiversity loss are out-pacing conservation efforts. The goals of restoration vary
widely from pure biocentric to anthropocentric motives. Biocentric motives focuses
on re-establishing native biota similar to those existed in pre-disturbance conditions
(e.g., species recovery and habitat restoration). Meantime when the degradation of
forest landscapes affects the wellbeing of the dependant people, it is necessary that
large areas need to be restored for re-establishing the impaired functioning or altered
structure of the landscape as a whole. Recently, such anthropocentric efforts are
getting recognised all over as an important mean for enhancing ecosystem functions,
biodiversity and thus improving human wellbeing.The Attappady hills, a part of the Nilgiri Biosphere Reserve of the Western Ghats has
undergone severe land degradation due to over exploitation and improper
management of natural resources coupled with faulty landuse practices. Land
degradation occurring continuously for the past five decades has increased poverty,
unemployment and emigration among the adivasis. In 1995, the Kerala Government
conceived a large eco-restoration program to restore the degraded forests and alleviate
poverty which is intricately linked to environmental degradation in the region and
formed the Attappady Hills Area Development Society (AHADS), an autonomous
body for implementing the project. With active participation of local communities,
AHADS restored many degraded forest fragments in the landscape. They adopted an
active restoration method for heavily degraded sites where sites were fenced to
remove grazing pressure, weeded frequently and planted with drought-resistant tree
species to minimize soil erosion. In contrast, a passive restoration method was
adopted for the less degraded sites where only fencing to facilitate natural
regeneration was provided. Nevertheless, their approach towards monitoring was
limited to revegetation. In either case biodiversity recovery form the important
indicator of successful intervention. In this thesis, I attempt to understand the process
of biodiversity recovery in the restored sites and develop a monitoring protocol based
on the recolonization of woody plants and ground-dwelling insect communities. I have adopted a chronosequence method for understanding the vegetation and insect
community structure of the restored habitats. The vegetation and insect community
showed high degrees of similarity across the age class of restored sites (Chapter 2).
Therefore, to understand the reasons for this similarity, I have developed a monitoring
scheme based on Before-After-Control-Impact (BACI) principles, by studying the
underlying ecological processes that determined the distributions of woody plant
(chapter 3) and ground-dwelling insect communities (Chapter 4) among the restored
sites. To recreate the history of each degraded habitat fragment, the woody plants were
characterised into three groups viz planted during past management (H), the
emergents (N) (are those that are naturally occurring without any interventions, other
than protection) and planted during AHADS eco-restoration program (P). The
distributions of the emergents reflected the parallel processes of past disturbance and
natural succession in the backdrop of anthropogenic interventions. Spatial analyses of
the woody plants were based on dispersal modes. Similarly, the distribution of various
insect taxonomic (ground-dwelling insects, ants and beetles) and functional feeding
groups (herbivores, detrivores and predators) were assessed by a range of variables
pertaining to habitat quality and quantity, at various spatial scales.
The Salient findings of this research are:
(1) The species richness of the ground-dwelling insects were generally higher in the
restored sites and distinct compared to the reference sites
The tragedy of the nature photography commons
Get PDFOver the last few decades, photography has become a crucial tool in the mainstreaming of biodiversity and its conservation. Today, it would be almost impossible to find any conservation outreach or marketing materials that do not include at least a few photographs. This em-phasis on photographic material is well justified, as there is evidence that photographs can have an important im-pact in our perceptions, attitudes and even behaviour to-wards nature (Kalof, Zammit-Lucia and Kelly 2011; Myers Jr., 2006). Examples of this are the efforts of the Sierra Club to establish some of the world’s first pro-tected areas in the USA; National Geographic’s coverage of the “Megatransect” trek by ecologist Michael Fay across the Congo basin; or the recent media reports on the large scale killing of Amur Falcons in the of Nagaland, India (Dalvi and Sreenivasan, 2012; Myers Jr., 2006). Such encouraging outcomes have lead to the creation of the field of “conservation photography” and to the forma-tion of organizations such as the International League of Conservation Photographers, who work specifically to disseminate the need for biodiversity conservation (Myers Jr., 2006
Attempts at controlling Teak Defoliator (Hyblaea puera Cramer, Lepidoptera, Hyblaeidae) with the entomopathogenic fungus, Metarhizium anisopliae (Metsch.): laboratory, nursery and field trials
No full textDefoliator pests often cause severe damage to commercially valuable timber trees, such as teak, grown in plantations, affecting the quality and quantity of the wood produced. Twenty-five isolates of an entomopathogenic fungus, Metarhizium anisopliae (Metsch.), derived from different forest habitats were tested for their efficacy against the Teak Defoliator, Hyblaea puera Cram. The median lethal concentration (LC50) for the isolates ranged from 0.65 to 947.41 × 105 conidia mL−1. Four isolates, viz. MIS2, MIS19, MIS7 and MIS1, were promising, having low LC50 values. A median lethal time (LT50) of 3.8 d was recorded for the isolates MIS2 and MIS7 when the moth larvae were exposed to a spore load of 107 conidia mL−1. Formulations composed of “MIS2 + MIS7 + 0.5% Pongamia pinnata seed oil” and “MIS2 + MIS7” proved to be superior against the Teak Defoliator, causing 94.73% and 93.93% mortality, respectively. Application of the formulation “MIS2 + MIS7 + 0.5% P. pinnata oil” resulted in 63.6% and 56.2% reduction in infestation in nurseries and plantations, respectively, while the formulation “MIS2 + MIS7” recorded 56.18% and 51.60% reduction. Our results indicate that M. anisopliae formulations could be an effective means of managing Teak Defoliator in plantations, particularly when combined with P. pinnata oil
Natural Windbreaks Sustain Bird Diversity in a Tea- Dominated Landscape
Get PDFWindbreaks often form networks of forest habitats that improve connectivity and thus conserve biodiversity, but little is known of such effects in the tropics. We determined bird species richness and community composition in windbreaks composed of remnant native vegetation amongst tea plantations (natural windbreaks), and compared it with the surrounding primary forests. Fifty-one, ten-minute point counts were conducted in each habitat type over three days. Despite the limited sampling period, our bird inventories in both natural windbreaks and primary forests were nearly complete, as indicated by bootstrap true richness estimator. Bird species richness and abundance between primary forests and windbreaks were similar, however a difference in bird community composition was observed. Abundances of important functional groups such as frugivores and insectivores did not vary between habitat types but nectarivores were more abundant in windbreaks, potentially as a result of the use of windbreaks as
traveling routes, foraging and nesting sites. This preliminary study suggests that natural windbreaks may be
important habitats for the persistence of bird species in a production landscape. However, a better understanding of the required physical and compositional characteristics for windbreaks to sustain bird communities is needed for effective conservation management
“Canopy-Less” Monitoring of Biodiversity and Climate Change: Signs of a Leaky Roof
No full textForest canopies are considered the last biotic frontier, and studies of canopy biota and related processes are just beginning to emerge in some parts of the world. Monitoring changes in biodiversity and related processes have gained much significance in the few last decades, particularly due to climate change. In addition, changes in biodiversity have been addressed by incorporating monitoring at various spatial and temporal scales that range from landscape-level changes, ecosystem dynamics, to population and species-level processes over extended time scales
Do Ecological Niche Model Predictions Reflect the Adaptive Landscape of Species?: A Test Using Myristica malabarica Lam., an Endemic Tree in the Western Ghats, India
Get PDFEcological niche models (ENM) have become a popular tool to define and predict the “ecological niche” of a species.
An implicit assumption of the ENMs is that the predicted ecological niche of a species actually reflects the adaptive landscape of the species. Thus in sites predicted to be highly suitable, species would have maximum fitness
compared to in sites predicted to be poorly suitable. As yet there are very few attempts to address this assumption.
Here we evaluate this assumption. We used Bioclim (DIVA GIS version 7.3) and Maxent (version 3.3.2) to predict the
habitat suitability of Myristica malabarica Lam., an economically important tree occurring in the Western Ghats, India. We located populations of the trees naturally occurring in different habitat suitability regimes (from highly suitable to poorly suitable) and evaluated them for their regeneration ability and genetic diversity. We also evaluated them for two plant functional traits, fluctuating asymmetry – an index of genetic homeostasis, and specific leaf weight – an index of primary productivity, often assumed to be good surrogates of fitness. We show a significant positive correlation between the predicted habitat quality and plant functional traits, regeneration index and genetic diversity of populations. Populations at sites predicted to be highly suitable had a higher regeneration and gene diversity compared to populations in sites predicted to be poor or unsuitable. Further, individuals in the highly suitable sites exhibited significantly less fluctuating asymmetry and significantly higher specific leaf weight compared to individuals
in the poorly suitable habitats. These results for the first time provide an explicit test of the ENM with respect to the plant functional traits, regeneration ability and genetic diversity of populations along a habitat suitability gradient. We discuss the implication of these resultsfor designing viable species conservation and restoration programs
Mapping Crop Types, Irrigated Ar eas, and Cropping Intensities in Heter ogeneous Landscapes of Southern India Using Multi-Temporal Medium-Resolution Imagery: Implications for Assessing Water Use in Agricultur e
No full textIn regions of water scarcity, mapping individual crops,
cropping intensities and irrigation can contribute significantly to understanding agricultural water use. But such mapping is challenging in landscapes dominated by small-scale traditional agricultural land holdings with high spatial and temporal heterogeneity. Here, we assessed the benefit of using multi-temporal 24 m resolution LISS-III imagery to characterize cropping systems in the Malaprabha basin of southern India. We used hierarchical stacked supervised classification to create three increasingly detailed maps showing: (a) single rainfed paddy rice versus continuously irrigated sugarcane, (b) irrigated versus rainfed areas, and (c) multiple cropping. Although increasing detail was accompanied by decreasing overall accuracies (89 percent, 74.6 percent and 60.1 percent respectively), using multi-temporal imagery out-performed single imagery alone in all cases. Results also led to higher estimates of total (69.8 percent) and irrigated (34.7 percent) cropland than previous single-imagery studies and census data, revealing the high uncertainty in crop estimates in
this region
Assessing relatedness and redundancy of forest monitoring and change indicators
No full textInformation on changes in forest structure and composition is required for informed, adaptive management and conservation. As the collection of such information requires field studies that are expensive, difficult, and time consuming, the prioritization of metrics can be of significant value. This study evaluates a number of metrics used to assess changes in forest structure and composition for a set of 59 forests in five countries – Kenya, India, Nepal, Uganda and USA. Changes in tree density are significantly positively correlated with changes in species richness, and changes in sapling/shrub density are significantly positively correlated with changes in species richness. Thus, rapid assessments of tree density change can be used to prioritize locations where there may be rapid deterioration in tree diversity, where the collection of detailed information on changes in species composition may be prioritized. Changes in tree density do not reflect changes in shrub and sapling density. The shrub and sapling layer appears to respond differently to human or natural disturbances compared to the tree layer, and may require separate assessment. Changes in tree DBH and tree height are not completely congruent, indicating that measurements of DBH and height may be required to accurately estimate changes in above ground carbon storage over time, for programs such as REDD that provide payment for carbon sequestration services
Fusarium proliferatum, an endophytic fungus from Dysoxylum binectariferum Hook.f, produces rohitukine, a chromane alkaloid possessing anti-cancer activity
No full textRohitukine is a chromane alkaloid possessing anti inflammatory, anti-cancer and immuno-modulatory properties. The compound was first reported from Amoora rohituka (Meliaceae) and later from Dysoxylum binectariferum (Meliaceae) and Schumanniophyton problematicum (Rubiaceae). Flavopiridol, a semi-synthetic derivative of rohitukine is a potent CDK inhibitor and is currently in Phase III clinical trials. In this study, the isolation of an endophytic fungus, Fusarium proliferatum (MTCC 9690) from the inner bark tissue of Dysoxylum binectariferum Hook.f (Meliaceae) is reported. The endophytic fungus produces rohitukine when cultured in shake flasks containing potato dextrose broth. The yield of rohitukine was 186 μg/100 g dry mycelial weight, substantially lower than that produced by the host tissue. The compound from the fungus was authenticated by comparing the LC–HRMS and LC–HRMS/MS spectra with those of the reference standard and that produced by the host plant. Methanolic extract of the fungus was cytotoxic against HCT-116 and MCF-7 human cancer cell lines (IC50 = 10 μg/ml for both cancer cell lines)
Forest transition pathways in Asia – studies from Nepal, India, Thailand, and Cambodia
No full textTropical forest habitat continues to decline globally, with serious consequences for environmental sustainability. The South/Southeast Asian landscapes represent one of the most challenging parts of the world to study issues of landscape change. High population densities in the region pose major threats to forest cover. Despite presentations of supposedly catastrophic declines in forest cover, substantial areas have been observed to maintain or increase forest cover in recent years. This research draws on data from Nepal, India, Thailand, and Cambodia to examine trajectories of forest-cover change along gradients of deforestation and reforestation. The gradients we observe extend from Cambodia, a still predominantly forested landscape, with development and change at initial stages, to Nepal which, despite having experienced large-scale forest clearing in the past, has considerable reforestation in recent years. Understanding these processes is critical for policymakers working on climate change and adaptation. This research allows us to link national-scale and local-scale analyses, in terms of both their similarities and differences, and also to see changes still in progress via the inclusion of regrowth and degradation classes, not just reforestation and deforestation