Agroecology; Conservation biology; Environmental Sustainability; Forest Ecology; Landscape and natural resource management; Remote sensing and GIS; Socio-economic vulnerability
18
Scopus Publications
Scopus Publications
Spatial patterns and health risks of heavy metals in groundwater along an urban–periurban gradient in Kamrup, Assam, India Manub Jyoti Talukdar, Pallabi Borah, Demsai Reang, Mayuri Chabukdhara Journal of Trace Elements and Minerals, 2026 Background This study investigated the spatial distribution, ecological risks and human health risks of heavy metals in groundwater across the highly built-up urban zone to the less dense surrounding landscapes (urban–periurban interface) of Kamrup district, Assam, India, one of the fastest growing regions in northeast India. Methodology Groundwater samples were collected from 123 sites and groundwater quality was evaluated using heavy metal evaluation index (HEI), degree of contamination (CD), water pollution index (WPI), and heavy metal toxicity load (HMTL). Health risks associated with drinking groundwater was assessed in terms of non-carcinogenic and carcinogenic risks. The Inverse Distance Weighting (IDW) technique was employed to assess the spatial patterns of metal concentrations and health risks in adults and children. Results Fe surpassed WHO and BIS standards in ∼90% of the studied samples. Spatial mapping highlighted distinct enrichment of Cd, Pb and Zn within the urban boundary, while Fe and Ni exhibited wider dispersion. Correlation and pollution indices analysis (HEI, CD, WPI, HMTL) confirmed localized hotspots influenced by both geogenic and anthropogenic sources including use of agrochemicals. Except for Cd in urban zone, the mean hazard quotients (HQ) for other metals were within safe limits (< 1) for adults and children. However, mean HI showed higher values in peri-urban zone as compared to urban zone. Carcinogenic health risks (CR) were primarily due to Cd and Ni for both adults and children with CR > 1 × 10⁻⁶ to 1 × 10⁻⁴. Conclusion Peri-urban zone showed higher contamination and overall groundwater chemistry in the urban–peri-urban region is dominated by Fe, while metals including Cd, Ni, and Pb showed localized enrichment with few sites requiring immediate attention. Integrated urban–peri-urban groundwater quality study using different approaches not only captures spatial heterogeneity, cumulative contamination severity, and differential health risks but can also help in decision making process for effective groundwater management in a growing urban landscape.
Variations in diversity and distribution patterns of tree species under protected areas of Barak valley in the Eastern Indian Himalayas Demsai Reang, Aparajita De, Ashesh Kumar Das Geology Ecology and Landscapes, 2026 Tropical forests are critical reservoirs of biodiversity yet remain among the most-threatened ecosystems. Protected areas (PA) play a vital role in conserving these forests and their rich biodiversity. The study assessed tree species diversity and conducted a comparative analysis across the three districts of Barak valley, Cachar (D1), Hailakandi (D2), and Karimganj (D3), Eastern Indian Himalayan region. 350 quadrats (10 m × 10 m) were randomly sampled within PA, documenting 194 tree species from 126 genera and 51 families. Species richness was highest under the PA of D1 (147), followed by D3 (99), and D2 (52). Tree basal cover showed identical trends, i.e. D1 (25.6 ± 0.49 m2 ha−1), D3 (22.7 ± 0.67 m2 ha−1) and D2 (20.2 ± 0.76 m2 ha−1). Biodiversity indices (Shannon, Margalef, Pielou, etc.) was highest for D1 than other districts, while stand density peaked in D3 (1798 ± 44 stems ha−1). The most dominant species include Artocarpus chama in D1 (IVI = 25.8) and D2 (IVI = 46.9), and Tectona grandis in D3 (IVI = 49). The presence of species listed under the IUCN Red List category includes vulnerable (n = 04), critically endangered (n = 02), endangered (n = 01), and near-threatened species (n = 01). The present study reveals the rich tree diversity within the PA of Barak valley, underscoring the need for district-specific forest conservation strategies to ensure long-term sustainability.
Piper agroforestry in the Indian Himalayas: indigenous peoples’ practices, policies and incentives Demsai Reang, Animekh Hazarika, Gudeta Weldesemayat Sileshi, Arun Jyoti Nath, Venkatesh Paramesh, W. Reshmi Singha, Ashesh Kumar Das Cabi Agriculture and Bioscience, 2024 Background Indigenous populations across the world play a significant role in sustainable land management and conservation of biodiversity. However, indigenous agricultural practices are rarely studied in depth and remain poorly documented in many regions of the world. Documenting such practices and identifying policies and incentives that affect them can unlock their potential for better land management and biodiversity conservation. Methods We undertook household surveys and focus group discussions to document indigenous practices and the values of trees in Piper (Piper betle) agroforestry practiced by the ethnic Khasi (Pnar) community in the Indian Eastern Himalayas. We also undertook an in-depth vegetation sampling to quantify variations in phytosociology and tree diversity with stand age in Piper agroforestry and nearby native forests. In addition, we undertook strengths, weaknesses, opportunities and threats (SWOT) analysis and a desk review to identify policies, market support structures and incentives affecting cultivation of Piper, a cash crop of global importance. Results Unlike in shifting cultivation, indigenous people do not fell trees in the Piper agroforestry; instead, they allow trees to regenerate naturally and also enrich by planting tree seedlings in the gaps. Depending on the stand age, 30–49 tree species were recorded in the Piper agroforestry compared to 39 in nearby natural forests. While tree density was higher in the natural forests, greater species richness, diversity and basal area was recorded in > 25 years old Piper agroforestry stands. However, landholders do not have legally transferable or heritable rights to the land or trees. Conclusion It is concluded that the Piper agroforestry provides a pathway for averting land degradation due to shifting cultivation, biodiversity conservation and improving livelihoods of the indigenous community. Although existing policies are supportive, Piper agroforestry is not currently benefiting from incentives and market support structures. We recommend implementation of policies, market support structures, incentives and payment for ecosystem services so that indigenous communities can benefit from the global ecosystem services they provide.
Climate change vulnerability and adaptation among farmers practicing shifting agriculture in the Indian Himalayas Animekh Hazarika, Arun Jyoti Nath, Demsai Reang, Rajiv Pandey, Gudeta W. Sileshi, Ashesh Kumar Das Environmental and Sustainability Indicators, 2024 The compounding and cascading effects of climate change induced by anthropogenic activities threaten the livelihoods of indigenous communities living in fragile ecosystems and practicing shifting agriculture in mountainous regions. This study assessed differences in household-level climate change vulnerability and socioeconomic profiles of indigenous communities practicing shifting agriculture in the Indian Himalayas using the Intergovernmental Panel on Climate Change (IPCC) framework. A total of 120 randomly selected households spread across 12 randomly chosen villages were surveyed, making sure that at least 10 households per village in Dima Hasao, Karbi Anglong, and Cachar districts of the state of Assam using the indicator-based household-level questionnaire to examine the cause and characteristics of vulnerability in the study region. Furthermore, focus group discussions were held in each village to delve into the community-based adaptive strategies employed by hill farmers, aiming to acquire an in-depth understanding of their approaches. The results revealed that villages with higher susceptibility to climate change are characterized by lower literacy levels, smaller land holdings with poor soil fertility, greater losses of crops due to extreme events, greater dependency on natural capital, and lower livelihood diversification. Villages with better land management techniques, higher decision-making abilities, agricultural diversification, and good market access had better adaptability to climate change. Agricultural diversification, transitioning from shifting agriculture to high-value cropping such as agroforestry, coupled with indigenous knowledge of the communities, provided tangible and intangible benefits and ecosystem services. Integrating high-value crops in shifting agriculture contributed to greater economic returns. In conclusion, shifting agriculture plays a vital role in the survival of ethnic culture, heritage, religious beliefs, and the livelihoods of nature-oriented hill farmers. Furthermore, improving fallow land management is crucial for maintaining ecological equilibrium and ensuring the sustainability of hill farmers’ lifestyles by fostering a community-environment-development nexus. Finally, we discuss the methodological implications of vulnerability assessment in the context of this study.
Carbon Stock Potential and Ecosystem Services Provisioned by Major Land-UseSystems in Southern Assam, India: A Meta-Analysis Sustainable Management and Conservation of Environmental Resources in India, 2024
The Shifting Cultivation Juggernaut: An Attribution Problem Arun Jyoti Nath, Demsai Reang, Gudeta W. Sileshi Global Challenges, 2022 Shifting cultivation entails clearing a delimited land and transforming it into arable land. Owing to its complexity, this system has been a subject of debate and intervention since the colonial‐era, and is often considered as the “tropical deforestation culprit.” Shifting cultivators are often labeled as “forest eaters” and are considered backward and primitive. Opponents of shifting cultivation often attribute the loss of forest cover to shifting cultivation, and favor intensification, claiming that commercial plantations are more productive. However, attempts to replace it have often failed due to inadequate understanding of the system and the decision‐making processes involved. On the other hand, a growing body of literature provides evidence that shifting cultivation is an ecologically and economically efficient practice. After a careful review of the literature, the authors conclude that the dichotomy of opinions is the consequence of the attribution problem. The authors also argue that the management of forest ecosystems will be challenging if policy and practice are not based on careful understanding of the power of this age‐old practice. Hence, there is a need for a careful diagnosis of this system and a rethink before claiming that the system is unsustainable and attempting to replace it with practices such as plantations.
