Biology subjects

Anujan, K.

Publications and source records attributed to Anujan, K..

5 recordsLinked to original sources

bioRxiv2024

Harmonising distributed tree inventory datasets across India can fill critical gaps in tropical ecology

AO_SCPLOWBSTRACTC_SCPLOWO_LIGlobal analyses of tree diversity and function are strongly biased geographically, with poor representation from forests of the Indian subcontinent. Even though data from India - representing two-thirds of the subcontinent and spanning a wide range of tree-based biomes - exists, a barrier to syntheses is the absence of accessible and standardised data. Further, with increasing human footprint across ecosystems, data from Indian landscapes, with their long history of human-nature interactions is a key link to understand the future of tropical forested landscapes. Given the long history of human-nature interactions and high human footprint in the region, accessible and standardized data from the subcontinent can enable understanding the future of tropical landscapes under increasing human footprints globally. C_LIO_LICombining literature searches with manual data retrieval, we assembled the INdia Tree Inventory dataset, INvenTree. INvenTree is the largest meta-dataset of peer-reviewed publications (n = 465) from 1991-2023 on geolocated plot-based tree inventories of multispecies communities from Indian ecosystems, in aggregate covering 4653.64 ha and all of its woody biomes. C_LIO_LIUsing INvenTree, we show extensive sampling across tropical moist and dry forests, the dominant ecosystem types in the country. However, most studies have low sampling effort (median sampled area = 2 ha) and data across studies is not openly accessible (73.33 % of studies representing 83.43% of the sampled area), potentially hindering inclusion into regional or global syntheses. C_LIO_LISignificantly, we show majority authorship from within the country; 82.8% of corresponding authors were from India and 73.33% of the studies had all authors affiliated with Indian institutions. We also identify ecological and conservation sampling priority regions based on forest cover and forest loss and set a blueprint for future sampling efforts in the country. C_LIO_LIBased on extensive Indian scholarship in forest ecology showcased through the INvenTree dataset, we see opportunity for regional collaboration to create scientific inferences that are larger and scalable, while prioritising data and knowledge equity. Harmonising these existing datasets, and synthesising historic and grey literature, will contribute enormously to understanding the human dimension of tropical ecology as well as informing regional management and conservation. C_LI

ecology↗

bioRxiv2023

Environmental correlates of tree reproductive phenology in a tropical state of India - insights from a citizen science project

Tropical tree reproductive phenology is sensitive to changing climate, but inter-individual and interannual variability at the regional scale is poorly understood. While large-scale and long-term datasets of environmental variables are available, reproductive phenology needs to be measured in-site, limiting the spatiotemporal scales of the data. We leveraged a unique dataset assembled by SeasonWatch, a citizen-science phenology monitoring programme in India to assess the environmental correlates of flowering in three ubiquitous and economically important tree species - jackfruit, mango and tamarind - in the south-western Indian state of Kerala. We explored (i) seasonal patterns in the flowering status of trees (ii) environmental correlates of flowering onset considering only trees with consecutive observations and (iii) spatiotemporal patterns in these environmental correlates to aid future hypotheses for changing phenology patterns. We used 165006 phenology observations spread over 19591 individual trees over 9 years. We first used bootstrapped circular statistics that accounts for observation biases in time to examine consistency in seasonality of flowering status over the whole season, and flowering onset across years and trees. Similar to results from cohort-based tree monitoring, we demonstrate seasonality in flowering status and onset across species, but also report large interannual and inter-individual variability. We then used used generalized linear mixed models with remotely sensed observations (ERA5-LAND) to show that some of the interannual variation in flowering onset across individuals was associated with environmental variables. Soil moisture, minimum temperature and solar radiation had significant associations with the onset of flowering but these effects were heterogeneous across species and habitats across Kerala. Our results become increasingly important in the face of large spatiotemporal change in the climate of this landscape and other tropical regions. We demonstrate the potential and limitations of citizen- science observations in making and testing predictions at scale for predictive climate science in tropical landscapes. Open Research StatementData are not yet provided. Environmental data used in this manuscript are from publicly available sources. All SeasonWatch data, the phenology data used in the manuscript, is licensed under the open-access creative commons license CC BY 4.0: https://creativecommons.org/licenses/by/4.0/ and is available upon request. Processed data and code used in this manuscript will be made publicly accessible through Zenodo upon acceptance of the manuscript. This manuscript does not use any novel code.

ecology↗

bioRxiv2022

Beyond the metropolis: Street tree densities and resident perceptions on ecosystem services in small urban centers in India

The role of urban street trees has been extensively studied in large metropolises, where they contribute significantly to faunal habitat, provide critical ecosystem services to residents and contribute to human well-being. On the other hand, rapidly urbanizing cities in India have been poorly studied, despite multiple types of irreplaceable losses related to tree cover. However, being early in their urbanization history, these centers also represent opportunity for urban sustainability with potentially high remnant vegetation and human-nature connections. While megacities in developed countries move towards biophilic urban planning and participatory decision making, basic information on tree communities and their perceived services is a bottleneck in achieving these goals in such small urban centers. We assessed the street tree community and resident perceptions of ecosystem service values in Kochi and Panjim, two coastal cities in India under rapid development, through a combination of field measurements (258 transects, 931 trees) and semi-structured interviews (497 individuals). We found that mean street tree density is low in both cities, especially so in Kochi, and corresponds to perceptions of recent change in tree cover (-28% in Kochi, -11% in Panjim). The street tree community in both cities were dominated by ornamental avenue trees such as Albizia saman and Peltophorum pterocarpum, but native coastal species like Cocos nucifera, Terminalia catappa and Thespesia populnea were also common. Despite recent urban growth, residents in both cities reported low value of trees for food, fodder and medicine, but high value for regulating services like shade and water. Moreover, we found strong evidence for aesthetic and cultural values of trees in both cities, including through qualitative interviews. Our study establishes critical baselines for biophilic planning in these small urban centers towards urban sustainability.

ecology↗

bioRxiv2022

Biodiversity effects on seedling biomass growth are modulated by light environment across functional groups

O_LITree biodiversity has the potential to ensure consistency in the functioning of forest ecosystems, not just over space, but over long-timescales by maintaining composition through recruitment. However, for continued buffering in the face of global environmental change, the sensitivity of biodiversity-ecosystem functioning relationships to heterogeneous environments needs to be understood. C_LIO_LISeedling recruitment in carbon-rich tropical forests is a result of biotic and abiotic drivers but their combined outcomes at the community-level remain poorly understood. Although biodiversity in seedling communities can potentially increase their growth and biomass accumulation, abiotic drivers like light can alter this effect through divergent effects on constituent species and functional groups. In forests with high baseline heterogeneity in microclimates, these processes can enhance or constrain regeneration. C_LIO_LIWe tested the effects and interactions between species richness and canopy cover on the growth of seedling communities consisting of tropical broad-leaved evergreen and deciduous forest species using a fully crossed manipulated experiment in the Andaman Islands, India and compared these with field observations from a long-term forest plot in the same landscape. C_LIO_LIWe show that in the critical seedling establishment phase, species richness and light increase community biomass independently. Accounting for variation across species, individual species on average accumulated more biomass in communities with both higher light and higher diversity. C_LIO_LIWe also show that overyielding in species rich communities fits expectations from a model of complementarity with non-random overyielding than selection or spatial insurance effects. C_LIO_LISynthesis Taken together, our results show that the potential for biodiversity to increase ecosystem functioning in seedling communities is modulated by light. Further understanding on the interaction of biodiversity with multiple abiotic drivers and their effect on regeneration dynamics is crucial for predicting future ecosystem functioning. C_LI

ecology↗

bioRxiv2019

Trophic complexity alters the diversity-multifunctionality relationship in experimental grassland mesocosms

Higher levels of diversity within trophic levels are necessary to sustain multiple ecosystem functions, but this diversity-multifunctionality relationship peaks at intermediate percent-function thresholds. The presence of multiple trophic levels, or trophic complexity, affects ecosystem multifunctionality but its effect on the diversity-multifunctionality relationship has not been experimentally tested. To test the sensitivity of the diversity-multifunctionality relationship to trophic complexity, we simultaneously manipulated plant diversity and trophic complexity in a multifactorial tall-grass prairie mesocosm experiment at Cedar Creek, Minnesota, USA. Trophic complexity altered the diversity-multifunctionality relationship, by lowering the height of the peak as well as by shifting to a negative effect at lower thresholds. These outcomes are consistent with decreases in both the "jack-of-all-trades" effect and complementarity among plant species. Our findings suggest that trophic complexity, which is experiencing widespread declines on a global scale, is important for sustaining ecosystem multifunctionality in the face of equally widespread declines in biodiversity.

ecology↗