Research |  Terrestrial

Long-term ecological monitoring (LeMon) of forest tree communities

Scientists from the National Centre for Biological Sciences in collaboration with ANET have been leading the LeMon (Long-term ecological monitoring) of forest tree communities, biomass and dynamics in the Andaman Islands since 2012. This is part of the Long-term Ecosystem Monitoring Network (LEMoN India), a country wide collaborative effort by NCBS, to establish and monitor tree communities, biomass and dynamics in a network of 1 ha forest plots across different forest types of India, and across environmental gradients in order to understand factors regulating long-term forest dynamics and potential responses of these systems to future climate change. Effective monitoring of populations, communities and ecosystems is critical to evaluating the success of conservation strategies and understanding the potential responses of natural ecosystems to global change. For long lived species such as trees, this monitoring must necessarily be long-term, as short term studies often fail to capture directional trends in vegetation dynamics, responses to episodic events or lagged responses to changing climatic drivers. This project provides critical insights into the structuring and functioning of forest communities, revealing subtle ways in which forests are changing over time in response to changing environmental drivers. This project further helps understand global carbon dynamics, and contributes significantly to the development of effective strategies for long-term sustainable forest management. Two monitoring plots have been established in Alexandria and Rutland islands that are part of the South Andamans Archipelago.
The team working on this project includes Prof. Mahesh Sankaran, Dr. Jayashree Ratnam and Dr. Karthik Teegalapalli from NCBS, along with Anand James Tirkey, Ledu Kujur, Sabien Horo, Dayani Chakravarthy & Shashi. During 2018 – 19, phenology observations were made on 174 trees in Rutland to record leafing, flowering and fruiting patterns and have completed one year of data collection. In the 2019 – 20 period, we plan to collect data on functional traits (wood density, specific leaf area, leaf Nitrogen and other traits) of trees and continue long-term monitoring of trees, seedlings, leaf litter, root growth and seed rain in the 2 one hectare plots in Alexandria and Rutland.

Identifying drivers of Social-ecological change and future priorities for research and management in the Andaman and Nicobar Islands

The Andaman and Nicobar Islands (ANI) are diverse and complex, ecologically and socially, with interactions between the natural, social and economic components. For effective resource management, evidence-based strategies that collate knowledge and perceptions of researchers and practitioners are critical. To understand researcher perceptions of socio-ecological change and to highlight future social-ecological research and management priorities, the study uses an online Delphi survey, where over 100 researchers and practitioners from the fields of ecology, conservation, and social sciences define research questions for the future, fitting the contexts of the islands. The project aims to highlight the drivers of change in the ANI, visually map the past and current research hotspots in ANI and highlight 50 top priority research questions. 

Another aspect of this research study focuses on the mangrove social-ecological systems (SESs) in the ANI islands – to understand how people use, perceive and govern these SESs in the context of environmental change, triggered by the 2004 Indian Ocean tsunami. The study framework consists of (i) mapping and analysing the involved actors, their discourses and the rules that govern the SES; (ii) understanding stakeholder use, knowledge and perceptions; (iii) using the adaptive cycle to understand the mangrove SES dynamics in Nicobar archipelago. Using mangroves as a lens, we contextualise and understand other interconnected environmental stressors in the islands. The study uses various methods including ethnography, content analysis of ‘grey’ and peer-reviewed literature and in-depth interviews with key stakeholders (resource users, managers, researchers and civil society).

This project is led by Meenakshi Poti, a Research Affiliate at Dakshin Foundation and doctoral candidate at the Université Libre de Bruxelles (ULB) and Vrije Universiteit Brussel (VUB). Meenakshi’s work focuses on responses to environmental change in small islands, with a specific focus on the Andaman and Nicobar Islands. 

Impacts of selective logging in the Andaman Islands

The tropical forests of the Andaman Islands have been logged for over 150 years but no study has examined carbon dynamics or plant functional shifts in response to logging. Responses are also likely to be mediated by the number of logging events at a site, but recovery patterns after multiple logging bouts are poorly studied. To address these gaps, this project is examining responses of plant communities and carbon along a selective-logging chronosequence in the tropical forests of the Andaman Islands, India. This project is part of Akshay Surendra’s recenlty-concluded master’s thesis at NCBS guided by Dr. Jayashree Ratnam and was conducted in collaboration with the Andaman and Nicobar Forest Department.

Currently Sameer Ghodke is studying the abundance, ecology and conservation status of two species of homalopsines from mangrove habitats of Andaman and Nicobar Islands. The study species include Cantoria violacea (Yellow-banded mangrove snake) and Gerarda prevostiana (Glossy marsh snake) and is revealing interesting information regarding their dietary preferences, distribution and population threats. As a three year project supported by the Andaman and Nicobar Forest Department, Sameer has finished the survey of North and Middle Andaman. The 2nd phase of the project will involve survey of South and Little Andaman and survey of the Nicobar Islands will be conducted in the 3rd year. Sameer Ghodke’s fascination for snakes of the Andaman and Nicobar Islands began when he first read Romulus Whitaker’s book, ‘Common Indian Snakes, A Field Guide’. Most of the amazing snake species mentioned in the book were from the Andaman & Nicobar Islands. Inspired by Romulus Whitaker and Harry Andrews to work in the islands, and guided by Ashok Captain, Sameer has been photo documenting and conducting research on island snakes since 2000. He has set up andamannicobarsnakes.com , a valuable online resource that includes his observations and photographs along with multiple published records.

Geckos are among the least explored fauna in the Andaman and Nicobar Islands. This main aims of this recently-concluded study led by Ashwini Mohan was to inventory species of geckos, map their distribution, and assess their conservation status. The study also assessed both inter- and intra- specific genetic diversity to prioritise species and islands for conservation. The project has sampled all currently recognized species: Cnemaspis andersoni, Cnemaspis sp., Hemidactylus aff. platyurus, Gehyra mutilata, Gekko verreauxi, Cyrtodactylus rubidus, Hemidactylus frenatus, Lepidodactylus lugubris, Phelsuma andamanensis, Gekko smithii, Hemidactylus garnotii, Hemiphyllodactylus typus and Ptychozoon nicobarensis. The aim has been to identify the genetic diversity of gecko species distributed on the Andaman and Nicobar islands, recognise the factors governing patterns of genetic diversity across space (dispersal ability, barriers of dispersal, isolation-by-distance, human mediated dispersal), prioritise gecko species and islands incorporating species and genetic diversity and identify endemic lineages, resolve taxonomic uncertainties, and identify origins of geckos in the islands. Supported by the Department of Environment and Forests, Ashwini and her team have successfully surveyed Landfall, North Andaman, Middle Andaman, South Andaman, Havelock, Interview, Long and Neil Island and parts of the Nicobar Islands. Samples are being processed in collaboration with Dr.Kartik Shanker’s lab in the Indian Institute of Science, Bangalore. Collections made for this study have been deposited at the Centre for Ecological Sciences, Indian Institute of Science.

The invasive Indian bullfrog (Hoplobatrachus tigerinus)

The islands are home to many introduced and invasive species. Elephants (Elephas maximus) were brought over to the Andaman Islands for forestry operations, deer (Axis axis, Rusa unicolor, Muntiacus muntjak, Axis porcinus) for sport hunting, tadpoles of bullfrogs (Hoplobatrachus tigerinus) entered the islands with juvenile fish imported from the mainland as it is often hard to differentiate between the two. Brought as pets to the Islands, cats and dogs hunt and destroy populations of indigenous birds and reptiles, whereas the common myna (Acridotheres tristis)once escaped from its cage, has caused havoc to the nests of other birds. These are just a few examples of introduced fauna that have significantly altered the ecosystem causing ecological and or economic damage.

Prof. John Measey, and Nitya Prakash Mohanty from the Centre for Invasion Biology (CIB), Stellenbosch University, South Africa along with Saw Issac, is studying the invasive Indian bullfrog Hoplobatrachus tigerinus in the Andaman Islands, evaluating the drivers of distribution, density, and the trophic impact of an early stage invader. This research aims to understand four major aspects of the Indian bullfrog’s invasion on the Andaman Islands: spatio-temporal patterns in distribution and dispersal, trophic impact of post-metamorphic stage, impact of larval stage,invasion dynamics and efficacy of potential management strategies.

Their study employed social science, traditional foraging ecology, manipulative experiments, simulation modelling, and species distribution modelling to answer key questions on the Indian bullfrog’s invasion. Post its introduction in 2000-01, the bullfrog has spread to several human-inhabited islands of the Andaman archipelago: North, Middle, South and Little Andaman Islands, and Swaraj Dweep and Shaheed Dweep Islands. Key dispersal pathways include contaminant of the aquaculture trade (tadpole stage) and intentional release for food (adult stage). Human-mediated translocations have resulted in accelerated invasive spread, by facilitating inter- and intra-island movement. The adult stage of bullfrogs prey upon several endemic vertebrates and may compete with larger native frogs due to overlapping diets. The larval stage of the bullfrog is carnivorous and under experimental condition, native tadpole survival is zero in the presence of bullfrog tadpoles. The bullfrog also causes socio-economic loss to the household level economy of poultry and aquaculture. Overall, the bullfrog is likely to increase it extra-limital range by spreading to new locations in the Andaman islands as well as to the Nicobar Islands that are located further away. Screening at points of entry is likely to be effective for small islands on both Andaman and Nicobar archipelagos due to the relatively low human traffic they experience.

Long-tailed Macaque on Great Nicobar

The Nicobar long-tailed macaque Macaca fascicularis umbrosa,an endemic primate listed under Schedule I of the Wildlife Protection Act of 1972, is considered to be a pest ‘weed’ macaque on the island of Great Nicobar in the Andaman and Nicobar Islands of India. Increasing animosity has been recorded towards this species in its range. The residents of Campbell Bay and surrounding areas on Great Nicobar island, have bore the brunt of crop raiding, as their agricultural fields and kitchen gardens are raided, almost on a daily basis, by macaque groups. Till date, there was no mitigation strategies that were effectively applied resulting in escalating levels of negative interactions across the island. This recently-concluded study aimed to understand the causes underlying this interaction by geographically mapping its occurrence, investigating the foraging ecology of selected macaque groups and conducting semi-structured data and perception interviews of the affected local communities. Led by Ishika Ramakrishna, this study constituted a part of her master’s dissertation (advised by Prof. Anindya Sinha of the National Institute of Advanced Studies and Dr. Ajith Kumar of the National Centre for Biological Sciences). The main aims of the project were to understand the nature and intensity of the interaction, to predict locations of high likelihood of conflict, and to develop potentially viable mitigation measures to reduce negative human–macaque interactions in the future.

This study has so far found that interactions between people and macaques, and perceptions thereof, are exacerbated by the adaptability of the macaques, natural disturbances, and unresolved conflict between the human communities and the island ecosystem itself. The macaques now supplement their staple of Pandanus fruit with human-provisioned resources like coconuts, bananas and vegetables, often grown for commercial purposes. The resulting losses are financial and personal in nature, with the familial background, socio-economic standing and the geographic positioning of the participants of this study affecting their perceptions. The study shows how factors that drive human-animal conflict are rarely simple and straightforward.

Ecological and social-economic importance and governance challenges of Chouldhari and Ograbranj wetlands

Wetlands ecosystems are some of the most productive and biologically diverse regions as they provide many important services to human society and are home to a wide range of flora and fauna. The wetlands in Chouldhari and Ograbraj are among the many wetland regions in South Andaman to become important habitats to a variety of avian species after their formation preceding the 2004 tsunami. However, a massive push for development to accommodate an increasing population and facilitate a boost in tourism is resulting in the reclamation of these rich ecosystems in order to build vast residential complexes and sports facilities. With the apparent lack of a local administrative body to look into matters concerning wetlands and the sites being either privately owned or under the jurisdiction of the state revenue department, the question of who manages these wetlands is a gap that this study aims to understand. Ms. Ashmita Biswas (supervised by Prof. Smriti Das, TER University and Dr. Madhuri Ramesh, Dakshin Foundation) is currently working on her master’s dissertation to assess the ecological and socio-economic importance of Chouldhari and Ograbranj wetlands of South Andaman.
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Preliminary avian species observations show that both Chouldhari and Ograbraj possess a rich diversity, with 31 and 45 species, respectively. However, this result also illuminates the consequences of development activities as the site at Chouldhari is currently witnessing more construction activities and reclamation than the one in Ograbraj.