Biology subjects

Osuri, A. M.

Publications and source records attributed to Osuri, A. M..

4 recordsLinked to original sources

bioRxiv2024

LONG-TERM ECOLOGICAL MONITORING IN INDIA: A SYNTHESIS

Long-term ecological monitoring (LTEM) is crucial for understanding ecological processes and responses to environmental change, informing management of natural resources, and biodiversity conservation. Systematic LTEM efforts began in India in the mid-1900s, but there is a lack of comprehensive synthesis of LTEM efforts in the country. Here, we use a wide-ranging questionnaire survey of ecologists coupled with a survey of published literature on LTEM efforts in India to synthesise their thematic and geographical spread, and types of data being collected, and identify key challenges to the establishment and maintenance of LTEM projects in the country. Studies monitor 77 unique subjects across 272 LTEM efforts in India. LTEM efforts are more often located in the Western Ghats and Eastern Himalaya, focused on forest vegetation, and monitoring factors such as abundance, distribution, species richness, and biomass. Regions such as North-Eastern, Eastern, Central, and North-Western India, ecosystems such as grasslands, deserts and wetlands, organisms such as macrofungi, amphibians, and reptiles (other than turtles) are underrepresented. Short turnover times of funding and permits were most frequently reported as hurdles in sustaining LTEM efforts. Data from LTEM efforts have been largely used to produce academic outputs such as journal articles, but have also found use for on-the-ground conservation efforts. Overall, this synthesis can help draw attention to the need for systematic long-term ecological monitoring, help efficient utilisation of existing long-term ecological data, identify regions, species and ecosystem components that are underrepresented in Indian LTEM efforts, foster collaborations, and serve as a starting point to address challenges in sustaining LTEM efforts in India.

ecology↗

bioRxiv2024

Taking stock of selective logging in the Andaman Islands, India: recent & legacy effects of timber extraction, assisted natural regeneration and a revamped working plan

Forest management is an evolving balance between biodiversity conservation and economic needs. A shift in Andaman Islands Working Plan mandate in 2000s reflects this evolution. Our study independently assesses the impact of said policy change on post-logging recovery of forests in Baratang and Middle Andaman. In 2017-18, we placed seventy-six 0.49ha plots across evergreen and deciduous patches and compared large-tree ([≥]180cm girth) density and diversity across forests that were logged after 2005 focussing on sustainability, logged in 1990s focussing on timber, logged twice in 1990s and after 2005, and unlogged forests. We assessed forest regeneration in thirty 0.01ha plots along a coupe road within forests logged after 2005. Forests logged after 2005 had similar density of large trees as forests logged in 1990s (despite having 1/3rd the recovery time), indicating reduced offtake or better recruitment. Along the unlogged--once-logged--twice-logged gradient, the dominance of Pterocarpus dalbergioides in deciduous patches decreased while the dominance of Diptercarpus sp. in evergreen patches increased. Compared to natural regeneration, proportionately more deciduous saplings were planted in both evergreen and deciduous patches. The new working plan maintains timber stock but not diversity. We make six simple recommendations to better align practice with the Working Plan mandate. SynthesisPost-2005 timber extraction policy in the Andaman Islands is partially successful but long-term forest health, in line with the working plan mandate, requires (1) lower timber offtake from deciduous patches and (2) targeted assisted regeneration of non-timber tree species.

ecology↗

bioRxiv2023

Structure and dynamics of secondary and mature rainforests: insights from South Asian long-term monitoring plots

We assessed tree community and carbon dynamics over 5 years in two 1-ha long-term ecosystem monitoring plots, one each in mature tropical rainforests (MR) and 10-year post-agroforestry secondary rainforests (SR) in Indias Western Ghats mountains. Both plots were established in 2017 and monitored annually six times. We expected (1) higher tree diversity, distinct species composition, and greater carbon stock in MR; (2) higher carbon sequestration rates in SR; and (3) carbon dynamics shaped by growth and mortality in SR and MR, respectively. The SR plot had fewer species (67 vs. 84), stored substantially less carbon (76 vs. 193 Mg), and comprised a distinct community with fewer late-successional species than MR. SR gained 5.8 Mg carbon, due to tree growth exceeding losses from mortality, while in MR mortality exceeded growth and recruitment resulting in a 3.3 Mg carbon decline over five years. While MR had higher tree diversity, carbon stocks and relatively intact composition, the high rates of biodiversity and carbon accrual in SR highlight the conservation and climate significance of post-agroforestry secondary forests. Moderate carbon losses noted here in MR, as in other mature South Asian tropical forests, is a cause for concern under ongoing climate change.

ecology↗

bioRxiv2023

Conservation value of low-elevation forests for birds in agroforestry-dominated landscapes in a biodiversity hotspot

O_LIProtected areas (PAs) and multi-use landscapes beyond PAs play important and complementary roles in conserving global biodiversity. Across the tropical forest biome, remnant forests and agroforestry plantations in mixed-use landscapes often have high taxonomic diversity, but their ability to sustain functionally and phylogenetically diverse assemblages and retain conservation-priority species is unclear. Additionally, our understanding of impacts of land-use change across species, function and communities is poor. C_LIO_LIIn Indias Western Ghats (WG) biodiversity hotspot, like in many other tropical regions, PAs cover just 12% of the land and are concentrated in higher elevations. Here, in an approximately 15,000 km2 landscape in the northern WG, we compared bird communities across six land-use categories: state-owned high-elevation PAs and low-elevation Reserved Forests beyond PAs, and privately-owned periodically clear-felled low-elevation forests and three types of low-elevation agroforestry plantations (cashew, mango, and rubber). C_LIO_LIWe sampled 184 line transects totalling 137.5 km across habitats, compared taxonomic, functional, and phylogenetic diversity metrics and used joint species distribution models to test for species-trait-habitat associations. C_LIO_LIForests in general and lowland forests in particular had higher taxonomic, functional and phylogenetic diversity, and higher occurrence probabilities of evergreen forest-affiliated, conservation-priority, and frugivores than agroforestry plantations. The ranking of land-use types varied across indicators, with rubber ranking higher than cashew and mango for functional and phylogenetic diversity but lower in species occurrence probabilities. C_LIO_LISynthesis and Applications: Our findings underscore the irreplaceability of less-disturbed forests for birds in mixed-use landscapes, especially when considering multiple dimensions of biodiversity, habitat specialists, and conservation-priority species. We advocate the simultaneous examination at multiple levels (community, species and traits) to determine the impacts of land-use change as divergent information of conservation importance is gleaned from each level. Reserved and private forests of low elevations of the Northern Western Ghats are critical for avian conservation, given that they harbour significant diversity, and the absence of representative PAs in the region. Given the vulnerability of these low-elevation forests to conversion for non-forestry activities and overexploitation for fuelwood, there is a need to develop viable models of partnership with landowners in these multi-use landscapes for ecological restoration of degraded forests. C_LI

ecology↗