scholarly journals Convergent acoustic community structure in South Asian dry and wet grassland birds

Biology Open ◽  
2021 ◽  
Author(s):  
Sutirtha Lahiri ◽  
Nafisa A. Pathaw ◽  
Anand Krishnan
Keyword(s):  
Community Structure ◽  
South Asian ◽  
Phylogenetic Diversity ◽  
Grassland Birds ◽  
Northeast India ◽  
Signal Space ◽  
Dry Grasslands ◽  
Wet Grassland ◽  
Acoustic Community ◽  
Northwest India

Although the study of bird acoustic communities has great potential in long-term monitoring and conservation, their assembly and dynamics remain poorly understood. Grassland habitats in South Asia comprise distinct biomes with unique avifauna, presenting an opportunity to address how community-level patterns in acoustic signal space arise. Similarity in signal space of different grassland bird assemblages may result from phylogenetic similarity, or because different bird groups partition the acoustic resource, resulting in convergent distributions in signal space. Here, we quantify the composition, signal space and phylogenetic diversity of bird acoustic communities from dry semiarid grasslands of Northwest India and wet floodplain grasslands of Northeast India, two major South Asian grassland biomes. We find that acoustic communities occupying these distinct biomes exhibit convergent, overdispersed distributions in signal space. However, dry grasslands exhibit higher phylogenetic diversity, and the two communities are not phylogenetically similar. The Sylvioidea encompasses half the species in the wet grassland acoustic community, with an expanded signal space compared to the dry grasslands. We therefore hypothesize that different clades colonizing grasslands partition the acoustic resource, resulting in convergent community structure across biomes. Many of these birds are threatened, and acoustic monitoring will support conservation measures in these imperiled, poorly-studied habitats.

scholarly journals Convergent acoustic community structure in South Asian dry and wet grassland birds

2020 ◽  
Author(s):  
Sutirtha Lahiri ◽  
Nafisa A. Pathaw ◽  
Anand Krishnan
Keyword(s):  
Community Structure ◽  
Phylogenetic Diversity ◽  
Grassland Birds ◽  
Northeast India ◽  
Signal Space ◽  
Dry Grasslands ◽  
Wet Grassland ◽  
Acoustic Community ◽  
Northwest India ◽  
Grassland Habitats

AbstractAlthough the study of bird acoustic communities has great potential to provide valuable conservation data, many aspects of their assembly and dynamics remain poorly understood. Grassland habitats in South Asia comprise distinct biomes with a unique avifauna, presenting an opportunity to address how community-level patterns in acoustic signal space arise. Similarity in signal space of different grassland bird communities may be due to phylogenetic similarity, or because different bird groups partition the acoustic resource, resulting in convergent distributions in signal space. Here, we quantify the composition, signal space and phylogenetic diversity of bird acoustic communities from the dry semiarid grasslands of Northwest India and the wet floodplain grasslands of Northeast India. We find that acoustic communities occupying these distinct biomes exhibit convergent signal space. However, dry grasslands exhibit higher phylogenetic diversity, and the two communities are not phylogenetically more similar than expected by chance. The Sylvioidea encompasses half the species in the wet grassland acoustic community, with an expanded signal space compared to the dry grasslands. Thus, dry and wet grassland communities are convergent in signal space despite differences in phylogenetic diversity. We therefore hypothesize that different clades colonizing grasslands partition the acoustic resource, resulting in convergent community structure across biomes. Many of the birds we recorded are highly threatened, and acoustic monitoring will support conservation measures in these imperiled, yet poorly-studied habitats.

scholarly journals First person – Sutirtha Lahiri

Biology Open ◽  
2021 ◽  
Vol 10 (6) ◽  
Keyword(s):  
Community Structure ◽  
South Asian ◽  
Grassland Birds ◽  
Early Career ◽  
First Person ◽  
Research Assistant ◽  
Early Career Researchers ◽  
Acoustic Community ◽  
Indian Institute Of Science ◽  
Selection Of

ABSTRACT First Person is a series of interviews with the first authors of a selection of papers published in Biology Open, helping early-career researchers promote themselves alongside their papers. Sutirtha Lahiri is first author on ‘Convergent acoustic community structure in South Asian dry and wet grassland birds’, published in BiO. Sutirtha is a research assistant in the lab of Dr Anand Krishnan at the Indian Institute of Science Education and Research (IISER) Pune, India, investigating whether biogeographically distinct grasslands display convergent acoustic community structure.

scholarly journals Acoustic community structure and seasonal turnover in tropical South Asian birds

2019 ◽  
Vol 30 (5) ◽  
pp. 1364-1374 ◽  
Author(s):  
Anand Krishnan
Keyword(s):  
Community Structure ◽  
Phylogenetic Diversity ◽  
Tropical Dry Forest ◽  
Bird Community ◽  
Urban Ecosystems ◽  
Dry Forest ◽  
Valuable Insight ◽  
Tropical Regions ◽  
Acoustic Community ◽  
Acoustic Space

Abstract Birds produce diverse acoustic signals, with coexisting species occupying distinct “acoustic niches” to minimize masking, resulting in overdispersion within acoustic space. In tropical regions of the world, an influx of migrants from temperate regions occurs during winter. The effects of these migrants on acoustic community structure and dynamics remain unstudied. Here, I show that in a tropical dry forest bird community occurring within an urban area in India, the influx of winter migrants is accompanied by a change in species composition of the acoustic community. However, in spite of this, the acoustic community remains overdispersed in acoustic niche space. The winter community of vocal birds at this study site additionally exhibits lower energy in the 4–7 kHz frequency bands (consistent with species singing less continuously), as well as lower phylogenetic diversity. My data are thus indicative of seasonal turnover in acoustic communities but suggest that acoustic niches and community structure are stable across seasons. Migrants occupy similar regions of acoustic space as residents and are relatively closely related to some of these species. Their arrival, therefore, leads to greater phylogenetic clustering in the winter and thus lower phylogenetic diversity, although the acoustic community remains overdispersed. Studying seasonal dynamics of acoustic communities thus provides valuable insight into assembly processes, as well as a potential framework for long-term monitoring of urban ecosystems.

scholarly journals Acoustic community structure and seasonal turnover in tropical South Asian birds

2019 ◽  
Author(s):  
Anand Krishnan
Keyword(s):  
Community Structure ◽  
Phylogenetic Diversity ◽  
Species Turnover ◽  
Bird Community ◽  
Urban Ecosystems ◽  
Valuable Insight ◽  
Tropical Regions ◽  
Acoustic Community ◽  
Acoustic Space ◽  
Coexisting Species

AbstractBirds produce diverse acoustic signals, with coexisting species occupying distinct ‘acoustic niches’ to minimize masking, resulting in overdispersion within acoustic space. In tropical regions of the world, an influx of migrants from temperate regions occurs during winter. The effects of these migrants on acoustic community structure and dynamics remain unstudied. Here, I show that in a tropical urban bird community, the influx of winter migrants is accompanied by a turnover of the acoustic community. However, in spite of this turnover, the acoustic community remains overdispersed in acoustic niche space. The winter acoustic community additionally exhibits lower frequency-band diversity, consistent with species singing less continuously, as well as lower phylogenetic diversity. My data thus suggests that acoustic niches and community structure are stable across seasons in spite of species turnover. Migrants occupy similar regions of acoustic space as residents, and are relatively closely related to some of these species. Their arrival therefore leads to greater phylogenetic clustering in the winter, and thus lower phylogenetic diversity, although the acoustic community remains overdispersed. Studying seasonal dynamics of acoustic communities thus provides valuable insight into assembly processes, as well as a potential framework for long-term monitoring of urban ecosystems.

Northeast India as an Indigenous Centre for the Domestication of Plants and Animals

2017 ◽  
Author(s):  
Manjil Hazarika
Keyword(s):  
South Asian ◽  
Close Association ◽  
Northeast India ◽  
Indian Culture ◽  
Rice Agriculture ◽  
Animal Domestication ◽  
History Of ◽  
The Relationship ◽  
Diverse Cultures

Northeast India is situated at the nexus of the South Asian, Southeast Asian, and East Asian biogeographical realms and harbours diverse biota, providing a unique opportunity to archaeologists and anthropologists for the study of the relationship between humans and their environment over the ages. Moreover, this region, the abode of diverse ethnic groups with diverse cultures and customs, hints at a long history of continuous and close association between humans and nature, which is important in the understanding of plant and animal domestication. Genetic analysis of present-day domesticates with their wild counterparts provides valuable insights into their differentiation, time of domestication, and changes in their morphological traits through control by humans. The chapter also elucidates the role played by rice in Northeast Indian culture and highlights the long-term history of rice agriculture in the region.

The phylogenetic position of the enigmatic Assam day gecko Cnemaspis cf. assamensis (Squamata: Gekkonidae) demonstrates a novel biogeographic connection between Northeast India and south India-Sri Lanka

2021 ◽  
pp. 1-13
Author(s):  
Ishan Agarwal ◽  
Rachunliu G. Kamei ◽  
Stephen Mahony
Keyword(s):  
Sri Lanka ◽  
Southeast Asia ◽  
South Asian ◽  
South India ◽  
Northeast India ◽  
Phylogenetic Position ◽  
Phylogenetic Studies ◽  
Molecular Phylogenetic ◽  
Nd2 Gene ◽  
Isolated Species

Abstract Northeast Indian biodiversity has long been considered to have a stronger affinity to Southeast Asian rather than Peninsular Indian fauna, however, few molecular phylogenetic studies have explored this hypothesis. In Asia, the polyphyletic gekkonid genus Cnemaspis sensu lato is comprised of two distantly related groups; one primarily from South Asia with some members in Southeast Asia, and the other exclusively from Southeast Asia. Cnemaspis assamensis is a systematically obscure and geographically isolated species (>1400 km from its nearest congeners) from the Brahmaputra River Valley in Northeast India. We provide the first molecular phylogenetic assessment of this species based on a partial ND2 gene fragment. Cnemaspis assamensis is determined to be a deeply divergent (Oligocene) member of the South Asian radiation and is sister to the podihuna clade which is endemic to Sri Lanka. The biogeographic implications of this find are discussed and this is suspected to represent a rare example of true disjunction between the wet zones of Northeast India and southern India/Sri Lanka. These results further emphasise the importance of Northeast India as a refuge for unique ancient faunal lineages.

Community structure of benthic amphipods in four estuaries of northwest India

2019 ◽  
Vol 27 ◽  
pp. 100532 ◽  
Author(s):  
Tatiparthi Srinivas ◽  
Soniya Sukumaran ◽  
Jyoti Mulik ◽  
Heidy Q. Dias
Keyword(s):  
Community Structure ◽  
Northwest India

South Asian summer monsoon in warm epochs of Mid-Holocene and end of 21st century; new insights from high resolution simulations

2020 ◽  
Author(s):  
Lekshmi Mudra B ◽  
Thazhe Purayil Sabin ◽  
Raghavan Krishnan
Keyword(s):  
High Resolution ◽  
South Asian ◽  
Asian Summer Monsoon ◽  
Hadley Cell ◽  
Monsoon Precipitation ◽  
South Asian Summer Monsoon ◽  
Indus Valley ◽  
Asian Summer ◽  
Northwest India

<p>The mid-Holocene (MH) was a warmer period, similar to the end of the 21st century climate under high emission realizations. The Indus valley civilization believed to be flourished under the expense of enhanced south Asian summer monsoon precipitation associated with the northward migration of the Inter Tropical Convergence Zone (ITCZ) during the mid-Holocene (MH). However, such an enhanced precipitation is not visible over the northwest India and Pakistan belt in future projection. The role of dynamical and various teleconnection factors behind the enhanced MH precipitation over the Indus valley region is still elusive due to the limitation of course resolution modelling efforts available so far as part of the various phases of Paleoclimate Modelling Intercomparison Projects (PMIP).  To overcome this limitation, we have designed high resolution Paleo-climate simulations using a state-of-the-art variable resolution global climate model (LMDZ: Laboratoire Meteorologie Dynamique and Z stand for zoom) which configured with a 35 km spatial resolution over the South Asian region. We conducted various sensitivity experiments to understand the role of dynamics and teleconnection in enhancing monsoon precipitation over the Indus valley in addition to the MH orbital conditions. Boundary conditions from the PMIP-3, CMIP5 and HadISST datasets utilized for various sensitive experiments. High resolution, clearly demonstrates value addition in simulating the enhanced MH precipitation over Northwest India and adjoining Indus basin associated with the northward migration of the ITCZ and shift in the ascending branch of Hadley cell. We explored the role of various oceanic and atmospheric factors responsible for this enhanced Indus valley precipitation through linearized moisture budget analysis and comparing the relative strength and position of Hadley cell. By further decomposing the thermodynamic and dynamic term into their advection and divergence component, we could demonstrate the role of moisture convergence due to the strengthened atmospheric circulation through the oceanic teleconnection, which additionally  plays a crucial role in enhanced MH precipitation comparing to the dynamical factors. Idealized simulation with the end of 21<sup>st</sup> century warm condition with the MH orbital forcing and various teleconnection patterns affirms that the thermodynamically induced future precipitation and circulation changes, may not be adequate to make a profound shift in the northern limit of the ITCZ towards its MH locale rather producing enhanced precipitation over the north Indian ocean and localized extreme precipitation over Indian landmass.</p><p><strong>Keywords: </strong>Indus Valley civilization, Mid-Holocene, Monsoons, Teleconnection, ITCZ and Hadley circulation</p>

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