1
|
Robin VV. Population genetics of animals in the wild to aid conservation: Uma Ramakrishnan-Recipient of the 2023 Molecular Ecology Prize. Mol Ecol 2024; 33:e17290. [PMID: 38339857 DOI: 10.1111/mec.17290] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2023] [Revised: 01/13/2024] [Accepted: 01/23/2024] [Indexed: 02/12/2024]
Affiliation(s)
- V V Robin
- IISER Tirupati, Tirupati, Andhra Pradesh, India
| |
Collapse
|
2
|
Jobin V, Das A, Harikrishnan CP, Chanda R, Lawrence S, Robin VV. Patterns of understory invasion in invasive timber stands of a tropical sky island. Ecol Evol 2023; 13:e9995. [PMID: 37066061 PMCID: PMC10099487 DOI: 10.1002/ece3.9995] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2022] [Revised: 03/25/2023] [Accepted: 03/28/2023] [Indexed: 04/18/2023] Open
Abstract
Current climate and land cover change threaten global mountaintops with increased spread of invasive species. Long-established plantations of invasive trees on these mountaintops can alter their surroundings, further increasing invader-facilitated invasion. Identifying the ecological conditions promoting such associations can help develop better management interventions. The Western Ghats's Shola Sky Islands (>1400 m MSL) host vast stretches of invasive tree plantations that sustain the colonization of other invasive woody, herbaceous, and fern species in their understories. Here, we analyzed vegetation and landscape variables from 232 systematically placed plots in randomly selected grids using non-metric multidimensional scaling and Phi coefficient approaches to examine patterns of association (positive interactions) between understory invasive species with specific invasive overstory species. We also conducted GLMM with zero inflation to determine the influence of environmental variables where such associations occur. We find that understory invasion of multiple species under the canopy of other invasives is widespread across the Shola Sky Islands. Stands of Eucalyptus host the colonization of 70% of non-native invasive species surveyed across the Shola Sky Islands. In particular, the Lantana camara invasion is strongly associated with Eucalyptus stands. We also found that climatic variables affect the colonization of understory woody invasive species, while invasion by exotic herbaceous species is associated with the density of road networks. Canopy cover impacts all invasives negatively, while fire incidence was negatively associated with invasion by Lantana spp. and the Pteridium spp. While the restoration of natural habitats primarily targets the highly invasive Acacia, less invasive Eucalyptus and Pinus are often not included. Our study suggests that retaining such invasive species in natural habitats, particularly protected areas, can hinder ongoing grassland restoration efforts by facilitating further invasions by multiple woody and herbaceous species.
Collapse
Affiliation(s)
- Varughese Jobin
- Indian Institute of Science Education and Research (IISER) TirupatiKarakambadi RoadTirupatiIndia
| | - Arundhati Das
- National Centre for Biological SciencesBengaluruIndia
| | - C. P. Harikrishnan
- Indian Institute of Science Education and Research (IISER) TirupatiKarakambadi RoadTirupatiIndia
| | - Ritobroto Chanda
- Indian Institute of Science Education and Research (IISER) TirupatiKarakambadi RoadTirupatiIndia
- Present address:
Centre for Ecological SciencesIndian Institute of ScienceCV Raman RoadBengaluru560012India
| | - Swapna Lawrence
- Indian Institute of Science Education and Research (IISER) TirupatiKarakambadi RoadTirupatiIndia
- Present address:
Wildlife Institute of IndiaWildlife Institute Rd, ChandrabaniDehradunUttarakhand248001India
| | - V. V. Robin
- Indian Institute of Science Education and Research (IISER) TirupatiKarakambadi RoadTirupatiIndia
| |
Collapse
|
3
|
Warudkar A, Goyal N, Kher V, Vinay KL, Chanda R, Bandi RS, Jenkins CN, Robin VV, Pimm S. Using the area of habitat to assess the extent of protection of India's birds. Biotropica 2022. [DOI: 10.1111/btp.13132] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Affiliation(s)
- Ashwin Warudkar
- Indian Institute of Science Education and Research Tirupati Tirupati India
| | - Naman Goyal
- Indian Institute of Science Education and Research Tirupati Tirupati India
| | - Varun Kher
- Indian Institute of Science Education and Research Tirupati Tirupati India
- Wildlife Institute of India Dehradun Uttarakhand India
| | - K. L. Vinay
- Indian Institute of Science Education and Research Tirupati Tirupati India
- Salim Ali Center for Ornithology and Natural History Coimbatore India
| | - Ritobroto Chanda
- Indian Institute of Science Education and Research Tirupati Tirupati India
- Centre for Ecological Sciences Indian Institute of Science Bengaluru India
| | - Raja Sekhar Bandi
- Indian Institute of Science Education and Research Tirupati Tirupati India
| | - Clinton N. Jenkins
- Department of Earth and Environment & Kimberly Green Latin American and Caribbean Center Florida International University Miami Florida USA
| | - V. V. Robin
- Indian Institute of Science Education and Research Tirupati Tirupati India
| | - Stuart L. Pimm
- Nicholas School of the Environment Durham North Carolina USA
- Saving Nature Durham North Carolina USA
| |
Collapse
|
4
|
Affiliation(s)
- Suyash Sawant
- Department of Biology Indian Institute of Science Education and Research (IISER) Tirupati Tirupati India
| | - Chiti Arvind
- Department of Biology Indian Institute of Science Education and Research (IISER) Tirupati Tirupati India
| | - Viral Joshi
- Department of Biology Indian Institute of Science Education and Research (IISER) Tirupati Tirupati India
| | - V. V. Robin
- Department of Biology Indian Institute of Science Education and Research (IISER) Tirupati Tirupati India
| |
Collapse
|
5
|
Dharmarajan G, Gupta P, Vishnudas CK, Robin VV. Cover Image. Ecol Lett 2021. [DOI: 10.1111/ele.13556] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
|
6
|
Arasumani M, Singh A, Bunyan M, Robin VV. Testing the efficacy of hyperspectral (AVIRIS-NG), multispectral (Sentinel-2) and radar (Sentinel-1) remote sensing images to detect native and invasive non-native trees. Biol Invasions 2021. [DOI: 10.1007/s10530-021-02543-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2022]
|
7
|
Dharmarajan G, Gupta P, Vishnudas CK, Robin VV. Anthropogenic disturbance favours generalist over specialist parasites in bird communities: Implications for risk of disease emergence. Ecol Lett 2021; 24:1859-1868. [PMID: 34120404 DOI: 10.1111/ele.13818] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2021] [Revised: 04/10/2021] [Accepted: 05/03/2021] [Indexed: 11/27/2022]
Abstract
Niche theory predicts specialists which will be more sensitive to environmental perturbation compared to generalists, a hypothesis receiving broad support in free-living species. Based on their niche breadth, parasites can also be classified as specialists and generalists, with specialists infecting only a few and generalists a diverse array of host species. Here, using avian haemosporidian parasites infecting wild bird populations inhabiting the Western Ghats, India as a model system, we elucidate how climate, habitat and human disturbance affects parasite prevalence both directly and indirectly via their effects on host diversity. Our data demonstrate that anthropogenic disturbance acts to reduce the prevalence of specialist parasite lineages, while increasing that of generalist lineages. Thus, as in free-living species, disturbance favours parasite communities dominated by generalist versus specialist species. Because generalist parasites are more likely to cause emerging infectious diseases, such biotic homogenisation of parasite communities could increase disease emergence risk in the Anthropocene.
Collapse
Affiliation(s)
- Guha Dharmarajan
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, USA.,Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - Pooja Gupta
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, USA.,Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, India
| | - C K Vishnudas
- Indian Institute of Science Education and Research Tirupati, Tirupati, Andhra Pradesh, India
| | - V V Robin
- Indian Institute of Science Education and Research Tirupati, Tirupati, Andhra Pradesh, India
| |
Collapse
|
8
|
Arasumani M, Bunyan M, Robin VV. Opportunities and challenges in using remote sensing for invasive tree species management, and in the identification of restoration sites in tropical montane grasslands. J Environ Manage 2021; 280:111759. [PMID: 33298397 DOI: 10.1016/j.jenvman.2020.111759] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/13/2020] [Revised: 11/23/2020] [Accepted: 11/24/2020] [Indexed: 06/12/2023]
Abstract
Tropical montane grasslands (TMG) support biodiverse and endemic taxa and provide vital ecosystem services to downstream communities. Nevertheless, invasive alien tree species across the world have threatened tropical grasslands and grassland endemic species. In India, TMG in the Shola Sky Islands of the Western Ghats have been reduced due to exotic tree invasions (Acacias, Pines, and Eucalyptus species). The loss of grassland habitat has, in turn, reduced the range sizes of species endemic to grasslands (plants, birds, amphibians, and mammals), driving some populations to local extinction. Grassland conversion to exotic trees has also impacted ecosystem services in the Western Ghats. Conserving existing grassland and restoring invaded habitat is critical to reverse these losses. This research focused on identifying grassland restoration sites using satellite images with a high spatial resolution (RapidEye). We used an object-oriented Random Forest classification to map the area for grassland restoration. We identified an area of 254 sq. km. as suitable for grassland restoration and an area of 362 sq. km. for grassland conservation and preventing invasion by exotic tree species. For restoration, we recommend careful removal of young and isolated exotic trees at the invasion front and restoring grasslands, instead of removing dense stands of mature exotic trees. Although our limited data indicate that areas with low fire frequency tend to be invaded, and areas invaded by exotic trees tend to burn at higher intensities, we recommend a broader investigation of these patterns to critically examine a potential role for the use of fire in invasive species management. We assume that removing exotic tree species in the identified restoration sites and restoring the grassland will help recover lost habitat and ensure the viability of indigenous and endemic species and increase streamflow.
Collapse
Affiliation(s)
- M Arasumani
- Indian Institute of Science Education and Research (IISER) Tirupati, Transit Campus, Karakambadi Road, Andhra Pradesh, 517507, India.
| | - Milind Bunyan
- Ashoka Trust for Research in Ecology and the Environment (ATREE), Royal Enclave, Sriramapura, Bangalore, Karnataka, 560064, India
| | - V V Robin
- Indian Institute of Science Education and Research (IISER) Tirupati, Transit Campus, Karakambadi Road, Andhra Pradesh, 517507, India
| |
Collapse
|
9
|
Gupta P, Vishnudas CK, Robin VV, Dharmarajan G. Correction to: Host phylogeny matters: Examining sources of variation in infection risk by blood parasites across a tropical montane bird community in India. Parasit Vectors 2021; 14:99. [PMID: 33557916 PMCID: PMC7869506 DOI: 10.1186/s13071-020-04508-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Affiliation(s)
- Pooja Gupta
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, USA. .,Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA. .,Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, 741246, India.
| | - C K Vishnudas
- Indian Institute of Science Education and Research Tirupati, Mangalam, Tirupati, 517507, India
| | - V V Robin
- Indian Institute of Science Education and Research Tirupati, Mangalam, Tirupati, 517507, India
| | - Guha Dharmarajan
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, USA.,Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, 741246, India
| |
Collapse
|
10
|
Natesh M, Vinay KL, Ghosh S, Jayapal R, Mukherjee S, Vijay N, Robin VV. Contrasting Trends of Population Size Change for Two Eurasian Owlet Species—Athene brama and Glaucidium radiatum From South Asia Over the Late Quaternary. Front Ecol Evol 2020. [DOI: 10.3389/fevo.2020.608339] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Climatic oscillations over the Quaternary have had a lasting impact on species’ distribution, evolutionary history, and genetic composition. Many species show dramatic population size changes coinciding with the last glacial period. However, the extent and direction of change vary across biogeographic regions, species-habitat associations, and species traits. Here we use genomic data to assess population size changes over the late Quaternary using the Pairwise Sequential Markovian Coalescent (PSMC) approach in two Eurasian Owlet species—the Spotted Owlet, Athene brama, and the Jungle Owlet, Glaucidium radiatum. While Spotted Owlets are typically associated with open habitats, Jungle Owlets are found in deciduous forests and scrublands. We find that the effective population size for the Spotted Owlet increased after the Interglacial period till the Last Glacial Maxima and subsequently declined toward the Mid-Holocene. On the other hand, effective population size estimates for the Jungle Owlet increased gradually throughout this period. These observations are in line with climatic niche model-based predictions for range size change for both species from a previous study and suggest that habitat associations at the local scale are important in determining responses to past climatic and vegetational changes. The Spotted Owlet result also aligns well with the expectation of open habitat expansion during the arid Glacial Maxima, whereas for the Jungle Owlet the contrasting expectation does not hold. Therefore, assessing the impacts of glacial history on population trajectories of multiple species with different habitat associations is necessary to understand the impacts of past climate on South Asian taxa.
Collapse
|
11
|
Gupta P, Vishnudas CK, Robin VV, Dharmarajan G. Host phylogeny matters: Examining sources of variation in infection risk by blood parasites across a tropical montane bird community in India. Parasit Vectors 2020; 13:536. [PMID: 33115505 PMCID: PMC7594458 DOI: 10.1186/s13071-020-04404-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 10/14/2020] [Indexed: 11/10/2022] Open
Abstract
Background Identifying patterns and drivers of infection risk among host communities is crucial to elucidate disease dynamics and predict infectious disease risk in wildlife populations. Blood parasites of the genera Plasmodium and Haemoproteus are a diverse group of vector-borne protozoan parasites that affect bird populations globally. Despite their widespread distribution and exceptional diversity, factors underlying haemosporidian infection risk in wild bird communities remain poorly understood. While some studies have examined variation in avian haemosporidian risk, researchers have primarily focused on host ecological traits without considering host phylogenetic relationships. In this study, we employ a phylogenetically informed approach to examine the association between host ecological traits and haemosporidian infection risk in endemic bird communities in the Western Ghats Sky Islands. Methods We used parasite sequence data based on partial mitochondrial cytochrome b gene, that was amplified from genomic DNA extracted from 1177 birds (28 species) across the Western Ghats to assess infection of birds with haemosporidian parasites. We employed a Bayesian phylogenetic mixed effect modelling approach to test whether haemosporidian infection risk was affected by seven species-specific and four individual-level ecological predictors. We also examined the effect of host phylogenetic relationships on the observed patterns of variation in haemosporidian infection risk by estimating phylogenetic signal. Results Our study shows that host ecological traits and host phylogeny differentially influence infection risk by Plasmodium (generalist parasite) and Haemoproteus (specialist parasite). For Plasmodium, we found that sociality, sexual dimorphism and foraging strata were important ecological predictors. For Haemoproteus, patterns of infection risk among host species were associated with sociality, species elevation and individual body condition. Interestingly, variance in infection risk explained by host phylogeny was higher for Haemoproteus parasites compared to Plasmodium. Conclusions Our study highlights that while host ecological traits promoting parasite exposure and host susceptibility are important determinants of infection risk, host phylogeny also contributes substantially to predicting patterns of haemosporidian infection risk in multi-host communities. Importantly, infection risk is driven by joint contributions of host ecology and host phylogeny and studying these effects together could increase our ability to better understand the drivers of infection risk and predict future disease threats. Graphical abstract ![]()
Collapse
Affiliation(s)
- Pooja Gupta
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, USA. .,Warnell School of Forestry and Natural Resources, University of Georgia, Athens, GA, 30602, USA. .,Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, 741246, India.
| | - C K Vishnudas
- Indian Institute of Science Education and Research Tirupati, Mangalam, Tirupati, 517507, India
| | - V V Robin
- Indian Institute of Science Education and Research Tirupati, Mangalam, Tirupati, 517507, India
| | - Guha Dharmarajan
- Savannah River Ecology Laboratory, University of Georgia, Aiken, SC, USA.,Indian Institute of Science Education and Research Kolkata, Mohanpur, West Bengal, 741246, India
| |
Collapse
|
12
|
Lele A, Arasumani M, Vishnudas CK, Joshi V, Jathanna D, Robin VV. Elevation and landscape change drive the distribution of a montane, endemic grassland bird. Ecol Evol 2020; 10:7755-7767. [PMID: 32760562 PMCID: PMC7391316 DOI: 10.1002/ece3.6500] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2019] [Revised: 05/13/2020] [Accepted: 05/31/2020] [Indexed: 11/10/2022] Open
Abstract
CONTEXT Tropical montane habitats support high biodiversity and are hotspots of endemism, with grasslands being integral components of many such landscapes. The montane grasslands of the Western Ghats have seen extensive land-use change over anthropogenic timescales. The factors influencing the ability of grassland-dependent species to persist in habitats experiencing loss and fragmentation, particularly in montane grasslands, are poorly known. OBJECTIVES We studied the relationship between the Nilgiri pipit Anthus nilghiriensis, a threatened endemic bird that typifies these montane grasslands, and its habitat, across most of its global distribution. We examined what habitat features make remnant grasslands viable, which is necessary for their effective management. METHODS We conducted 663 surveys in 170 sites and used both single-season occupancy modeling and N-mixture modeling to account for processes influencing detection, presence, and abundance. RESULTS Elevation had a positive influence on species presence, patch size had a moderate positive influence, and patch isolation had a moderate negative influence. Species abundance was positively influenced by elevation and characteristics related to habitat structure, and negatively influenced by the presence of invasive woody vegetation. CONCLUSIONS The strong effect of elevation on the highly range-restricted Nilgiri pipit is likely to make it vulnerable to climate change. This highly range-restricted species is locally extinct at several locations, and persists at low densities in remnants of its habitat left by recent fragmentation. Our findings indicate a need to control and reverse the spread of exotic woody invasives to preserve the grasslands themselves and the specialist species dependent upon them.
Collapse
Affiliation(s)
- Abhimanyu Lele
- Indian Institute of Science Education and Research TirupatiTirupatiAndhra PradeshIndia
- Present address:
Committee on Evolutionary BiologyUniversity of ChicagoChicagoIllinoisUSA
- Present address:
Negaunee Integrative Research CenterField Museum of Natural HistoryChicagoIllinoisUSA
| | - M. Arasumani
- Indian Institute of Science Education and Research TirupatiTirupatiAndhra PradeshIndia
- Hume Centre for Ecology and Wildlife BiologyKalpettaKeralaIndia
- The Gandhigram Rural InstituteGandhigramTamil NaduIndia
| | - C. K. Vishnudas
- Indian Institute of Science Education and Research TirupatiTirupatiAndhra PradeshIndia
- Hume Centre for Ecology and Wildlife BiologyKalpettaKeralaIndia
| | - Viral Joshi
- Indian Institute of Science Education and Research TirupatiTirupatiAndhra PradeshIndia
| | | | - V. V. Robin
- Indian Institute of Science Education and Research TirupatiTirupatiAndhra PradeshIndia
| |
Collapse
|
13
|
Gupta P, Vishnudas CK, Ramakrishnan U, Robin VV, Dharmarajan G. Geographical and host species barriers differentially affect generalist and specialist parasite community structure in a tropical sky-island archipelago. Proc Biol Sci 2019; 286:20190439. [PMID: 31161909 DOI: 10.1098/rspb.2019.0439] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Understanding why some parasites emerge in novel host communities while others do not has broad implications for human and wildlife health. In the case of haemosporidian blood parasites, epidemic wild bird mortalities on oceanic islands have been linked to Plasmodium spp., but not genera like Haemoproteus. Indeed, Haemoproteus is absent from many oceanic islands. By contrast, birds on continental islands share long coevolutionary histories with both Plasmodium and Haemoproteus, and are thus ideal model systems to elucidate eco-evolutionary endpoints associated with these parasites in oceanic islands. Here, we examine eco-evolutionary dynamics of avian haemosporidian in the Shola sky-island archipelago of the Western Ghats, India. Our analyses reveal that compared to Plasmodium, Haemoproteus lineages were highly host-specific and diversified via co-speciation with their hosts. We show that community structure of host-generalist Plasmodium was primarily driven by geographical factors (e.g. biogeographic barriers), while that of host-specialist Haemoproteus was driven by host species barriers (e.g. phylogenetic distance). Consequently, a few host species can harbour a high diversity of Plasmodium lineages which, in turn, are capable of infecting multiple host species. These two mechanisms can act in concert to increase the risk of introduction, establishment, and emergence of novel Plasmodium lineages in island systems.
Collapse
Affiliation(s)
- Pooja Gupta
- 1 Savannah River Ecology Laboratory, University of Georgia , Aiken, SC , USA.,2 Warnell School of Forestry and Natural Resources, University of Georgia , Athens, GA 30602 , USA
| | - C K Vishnudas
- 3 Indian Institute of Science Education and Research Tirupati , Mangalam, Tirupati 517507 , India
| | - Uma Ramakrishnan
- 4 National Centre for Biological Sciences, TIFR , Bangalore 560065 , India
| | - V V Robin
- 3 Indian Institute of Science Education and Research Tirupati , Mangalam, Tirupati 517507 , India
| | - Guha Dharmarajan
- 1 Savannah River Ecology Laboratory, University of Georgia , Aiken, SC , USA
| |
Collapse
|
14
|
Koparde P, Mehta P, Mukherjee S, Robin VV. Quaternary climatic fluctuations and resulting climatically suitable areas for Eurasian owlets. Ecol Evol 2019; 9:4864-4874. [PMID: 31031949 PMCID: PMC6476768 DOI: 10.1002/ece3.5086] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2018] [Revised: 02/24/2019] [Accepted: 02/26/2019] [Indexed: 11/10/2022] Open
Abstract
AIM The nested pattern in the geographical distribution of three Indian owlets, resulting in a gradient of endemicity, is hypothesized to be an impact of historical climate change. In current time, the Forest Owlet Athene blewitti is endemic to central India, and its range is encompassed within the ranges of the Jungle Owlet Glaucidium radiatum (distributed through South Asia) and Spotted Owlet Athene brama (distributed through Iran, South and Southeast Asia). Another phylogenetically close species, Little Owl Athene noctua, which is largely Palearctic in distribution, is hypothesized to have undergone severe range reduction during the Last Glacial Maximum, showing a postglacial expansion. The present study tests hypotheses on the possible role of Quaternary climatic fluctuations in shaping geographical ranges of owlets. METHODS We used primary field observations, open access data, and climatic niche modeling to construct climatic niches of four owlets for four periods, the Last Interglacial (~120-140 Ka), Last Glacial Maximum (~22 Ka), Mid-Holocene (~6 Ka), and Current (1960-1990). We performed climatic niche extent, breadth, and overlap analyses and tested if climatically suitable areas for owlets are nested in a relatively stable climate. RESULTS Climatically suitable areas for all owlets examined underwent cycles of expansion and reduction or a gradual expansion or reduction since the Last Interglacial. The Indian owlets show significant climatic niche overlap in the current period. Climatically suitable areas for Little Owl shifted southwards during the Last Glacial Maximum and expanded northwards in the postglaciation period. For each owlet, the modeled climatic niches were nested in climatically stable areas. MAIN CONCLUSIONS The study highlights the impact of Quaternary climate change in shaping the present distribution of owlets. This is relevant to the current scenario of climate change and global warming and can help inform conservation strategies, especially for the extremely range-restricted Forest Owlet.
Collapse
Affiliation(s)
- Pankaj Koparde
- Division of Conservation BiologySálim Ali Centre for Ornithology and Natural HistoryCoimbatoreIndia
- Manipal Academy of Higher EducationManipalIndia
- Indian Institute of Science Education and Research (IISER)TirupatiIndia
| | - Prachi Mehta
- Wildlife Research and Conservation SocietyPuneIndia
| | - Shomita Mukherjee
- Division of Conservation BiologySálim Ali Centre for Ornithology and Natural HistoryCoimbatoreIndia
| | - V. V. Robin
- Indian Institute of Science Education and Research (IISER)TirupatiIndia
| |
Collapse
|
15
|
Buxton RT, Agnihotri S, Robin VV, Goel A, Balakrishnan R. Acoustic indices as rapid indicators of avian diversity in different land-use types in an Indian biodiversity hotspot. ACTA ACUST UNITED AC 2018. [DOI: 10.22261/jea.gwpzvd] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Passive acoustic monitoring is a potentially valuable tool in biodiversity hotspots, where surveying can occur at large scales across land conversion types. However, in order to extract meaningful biological information from resulting enormous acoustic datasets, rapid analytical techniques are required. Here we tested the ability of a suite of acoustic indices to predict avian bioacoustic activity in recordings collected from the Western Ghats, a biodiversity hotspot in southwestern India. Recordings were collected at 28 sites in a range of land-use types, from tea, coffee, and cardamom plantations to remnant forest stands. Using 36 acoustic indices we developed random forest models to predict the richness, diversity, and total number of avian vocalizations observed in recordings. We found limited evidence that acoustic indices predict the richness and total number of avian species vocalizations in recordings (R2 < 0.51). However, acoustic indices predicted the diversity of avian species vocalizations with high accuracy (R2 = 0.64, mean squared error = 0.17). Index models predicted low and high diversity best, with the highest residuals for medium diversity values and when continuous biological sounds were present (e.g., insect sounds >8 sec). The acoustic complexity index and roughness index were the most important for predicting avian vocal diversity. Avian species richness was generally higher among shade-grown crops than in the open tea plantation. Our results suggest that models incorporating acoustic indices can accurately predict low and high avian species diversity from acoustic recordings. Thus, ecoacoustics could be an important contributor to biodiversity monitoring across landscapes like the Western Ghats, which are a complex mosaic of different land-use types and face continued changes in the future.
Collapse
|
16
|
Koparde P, Mehta P, Reddy S, Ramakrishnan U, Mukherjee S, Robin VV. The critically endangered forest owlet Heteroglaux blewitti is nested within the currently recognized Athene clade: A century-old debate addressed. PLoS One 2018; 13:e0192359. [PMID: 29401484 PMCID: PMC5798823 DOI: 10.1371/journal.pone.0192359] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Accepted: 01/21/2018] [Indexed: 11/23/2022] Open
Abstract
Range-restricted species generally have specific niche requirements and may often have unique evolutionary histories. Unfortunately, many of these species severely lack basic research, resulting in poor conservation strategies. The phylogenetic relationship of the Critically Endangered Forest Owlet Heteroglaux blewitti has been the subject of a century-old debate. The current classifications based on non-phylogenetic comparisons of morphology place the small owls of Asia into three genera, namely, Athene, Glaucidium, and Heteroglaux. Based on morphological and anatomical data, H. blewitti has been alternatively hypothesized to belong within Athene, Glaucidium, or its own monotypic genus Heteroglaux. To test these competing hypotheses, we sequenced six loci (~4300 bp data) and performed phylogenetic analyses of owlets. Mitochondrial and nuclear trees were not congruent in their placement of H. blewitti. However, both mitochondrial and nuclear combined datasets showed strong statistical support with high maximum likelihood bootstrap (>/ = 90) and Bayesian posterior probability values (>/ = 0.98) for H. blewitti being nested in the currently recognized Athene group, but not sister to Indian A. brama. The divergence of H. blewitti from its sister taxa was between 4.3 and 5.7 Ma coinciding with a period of drastic climatic changes in the Indian subcontinent. This study presented the first genetic analysis of H. blewitti, a Critically Endangered species, and addressed the long debate on the relationships of the Athene-Heteroglaux-Glaucidium complex. We recommend further studies with more data and complete taxon sampling to understand the biogeography of Indian Athene species.
Collapse
Affiliation(s)
- Pankaj Koparde
- Division of Conservation Biology, Sálim Ali Centre for Ornithology & Natural History, Coimbatore, Tamil Nadu, India
- Manipal Academy of Higher Education, Madhav Nagar, Manipal, Karnataka, India
- Indian Institute of Science Education and Research, Tirupati, Andhra Pradesh, India
- * E-mail:
| | - Prachi Mehta
- Wildlife Research and Conservation Society, Pune, Maharashtra, India
| | - Sushma Reddy
- Loyola University, Chicago, Illinois, United States of America
| | - Uma Ramakrishnan
- National Centre for Biological Science, TIFR, Bangalore, Karnataka, India
| | - Shomita Mukherjee
- Division of Conservation Biology, Sálim Ali Centre for Ornithology & Natural History, Coimbatore, Tamil Nadu, India
| | - V. V. Robin
- Indian Institute of Science Education and Research, Tirupati, Andhra Pradesh, India
| |
Collapse
|
17
|
Arasumani M, Khan D, Das A, Lockwood I, Stewart R, Kiran RA, Muthukumar M, Bunyan M, Robin VV. Not seeing the grass for the trees: Timber plantations and agriculture shrink tropical montane grassland by two-thirds over four decades in the Palani Hills, a Western Ghats Sky Island. PLoS One 2018; 13:e0190003. [PMID: 29320520 PMCID: PMC5761842 DOI: 10.1371/journal.pone.0190003] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2017] [Accepted: 12/06/2017] [Indexed: 11/19/2022] Open
Abstract
Tropical montane habitats, grasslands, in particular, merit urgent conservation attention owing to the disproportionate levels of endemic biodiversity they harbour, the ecosystem services they provide, and the fact that they are among the most threatened habitats globally. The Shola Sky Islands in the Western Ghats host a matrix of native forest-grassland matrix that has been planted over the last century, with exotic timber plantations. The popular discourse on the landscape change is that mainly forests have been lost to the timber plantations and recent court directives are to restore Shola forest trees. In this study, we examine spatiotemporal patterns of landscape change over the last 40 years in the Palani Hills, a significant part of the montane habitat in the Western Ghats. Using satellite imagery and field surveys, we find that 66% of native grasslands and 31% of native forests have been lost over the last 40 years. Grasslands have gone from being the dominant, most contiguous land cover to one of the rarest and most fragmented. They have been replaced by timber plantations and, to a lesser extent, expanding agriculture. We find that the spatial pattern of grassland loss to plantations differs from the loss to agriculture, likely driven by the invasion of plantation species into grasslands. We identify remnant grasslands that should be prioritised for conservation and make specific recommendations for conservation and restoration of grasslands in light of current management policy in the Palani Hills, which favours large-scale removal of plantations and emphasises the restoration of native forests.
Collapse
Affiliation(s)
- M. Arasumani
- INTACH-Kodaikanal, Melati, Wilbet house, Kodaikanal, India
- The Gandhigram Rural Institute, Gandhigram, Dindigul, Tamil Nadu, India
- Indian Institute of Science Education and Research Tirupati (IISER-Tirupati), Mangalam, Tirupati, India
| | - Danish Khan
- INTACH-Kodaikanal, Melati, Wilbet house, Kodaikanal, India
| | - Arundhati Das
- Arundhati Das, Samvriddhi Gardenia, Byatarayanapura, Bangalore, India
| | | | - Robert Stewart
- Vattakanal Conservation Trust, Vattakanal, Kodaikanal, India
| | - Ravi A. Kiran
- Botanical Survey of India, Coimbatore, Tamil Nadu, India
| | - M. Muthukumar
- The Gandhigram Rural Institute, Gandhigram, Dindigul, Tamil Nadu, India
| | - Milind Bunyan
- Ashoka Trust for in Research on Ecology and the Environment, Srirampura, Bangalore, India
| | - V. V. Robin
- INTACH-Kodaikanal, Melati, Wilbet house, Kodaikanal, India
- Indian Institute of Science Education and Research Tirupati (IISER-Tirupati), Mangalam, Tirupati, India
| |
Collapse
|
18
|
Wickramasinghe N, Robin VV, Ramakrishnan U, Reddy S, Seneviratne SS. Non-sister Sri Lankan white-eyes (genus Zosterops) are a result of independent colonizations. PLoS One 2017; 12:e0181441. [PMID: 28792950 PMCID: PMC5549887 DOI: 10.1371/journal.pone.0181441] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 07/02/2017] [Indexed: 11/18/2022] Open
Abstract
Co-occurrence of closely related taxa on islands could be attributed to sympatric speciation or multiple colonization. Sympatric speciation is considered to be rare in small islands, however multiple colonizations are known to be common in both oceanic and continental islands. In this study we investigated the phylogenetic relatedness and means of origin of the two sympatrically co-occurring Zosterops white-eyes, the endemic Zosterops ceylonensis and its widespread regional congener Z. palpebrosus, in the island of Sri Lanka. Sri Lanka is a continental island in the Indian continental shelf of the Northern Indian Ocean. Our multivariate morphometric analyses confirmed the phenotypic distinctness of the two species. Maximum Likelihood and Bayesian phylogenetic analyses with ~2000bp from two mitochondrial (ND2 and ND3) and one nuclear (TGF) gene indicated that they are phylogenetically distinct, and not sister to each other. The two subspecies of the peninsula India; Z. p. egregius of Sri Lanka and India and Z. p. nilgiriensis of Western Ghats (India) clustered within the Z. palpebrosus clade having a common ancestor. In contrast, the divergence of the endemic Z. ceylonensis appears to be much deeper and is basal to the other Zosterops white-eyes. Therefore we conclude that the two Zosterops species originated in the island through independent colonizations from different ancestral lineages, and not through island speciation or multiple colonization from the same continental ancestral population. Despite high endemism, Sri Lankan biodiversity is long considered to be a subset of southern India. This study on a speciose group with high dispersal ability and rapid diversification rate provide evidence for the contribution of multiple colonizations in shaping Sri Lanka’s biodiversity. It also highlights the complex biogeographic patterns of the South Asian region, reflected even in highly vagile groups such as birds.
Collapse
Affiliation(s)
- Nelum Wickramasinghe
- Avian Evolution Node, Department of Zoology and Environment Sciences, Faculty of Science, University of Colombo, Colombo, Sri Lanka
- National Center for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - V. V. Robin
- National Center for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Uma Ramakrishnan
- National Center for Biological Sciences, Tata Institute of Fundamental Research, Bangalore, India
| | - Sushma Reddy
- Biology Department, Loyola University Chicago, Chicago, Illinois, United States of America
| | - Sampath S. Seneviratne
- Avian Evolution Node, Department of Zoology and Environment Sciences, Faculty of Science, University of Colombo, Colombo, Sri Lanka
- * E-mail:
| |
Collapse
|
19
|
Purushotham CB, Robin VV. Sky island bird populations isolated by ancient genetic barriers are characterized by different song traits than those isolated by recent deforestation. Ecol Evol 2017; 6:7334-7343. [PMID: 28725401 PMCID: PMC5513277 DOI: 10.1002/ece3.2475] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2016] [Accepted: 08/19/2016] [Indexed: 02/06/2023] Open
Abstract
Various mechanisms of isolation can structure populations and result in cultural and genetic differentiation. Similar to genetic markers, for songbirds, culturally transmitted sexual signals such as breeding song can be used as a measure of differentiation as songs can also be impacted by geographic isolation resulting in population‐level differences in song structure. Several studies have found differences in song structure either across ancient geographic barriers or across contemporary habitat barriers owing to deforestation. However, very few studies have examined the effect of both ancient barriers and recent deforestation in the same system. In this study, we examined the geographic variation in song structure across six populations of the White‐bellied Shortwing, a threatened and endemic songbird species complex found on isolated mountaintops or “sky islands” of the Western Ghats. While some sky islands in the system are isolated by ancient valleys, others are separated by deforestation. We examined 14 frequency and temporal spectral traits and two syntax traits from 835 songs of 38 individuals across the six populations. We identified three major song clusters based on a discriminant model of spectral traits, degree of similarity of syntax features, as well as responses of birds to opportunistic playback. However, some traits like complex vocal mechanisms (CVM), relating to the use of syrinxes, clearly differentiated both ancient and recently fragmented populations. We suggest that CVMs may have a cultural basis and can be used to identify culturally isolated populations that cannot be differentiated using genetic markers or commonly used frequency‐based song traits. Our results demonstrate the use of bird songs to reconstruct phylogenetic groups and impacts of habitat fragmentation even in complex scenarios of historic and contemporary isolation.
Collapse
Affiliation(s)
- Chetana B Purushotham
- National Institute of Advanced Studies Indian Institute of Science Campus Bangalore India
| | - V V Robin
- National Institute of Advanced Studies Indian Institute of Science Campus Bangalore India.,Present address: V. V. Robin, Indian Institute of Science Education and Research Tirupati Tirupati India
| |
Collapse
|
20
|
Robin VV, Vishnudas CK, Gupta P, Rheindt FE, Hooper DM, Ramakrishnan U, Reddy S. Two new genera of songbirds represent endemic radiations from the Shola Sky Islands of the Western Ghats, India. BMC Evol Biol 2017; 17:31. [PMID: 28114902 PMCID: PMC5259981 DOI: 10.1186/s12862-017-0882-6] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Accepted: 01/11/2017] [Indexed: 12/03/2022] Open
Abstract
Background A long-standing view of Indian biodiversity is that while rich in species, there are few endemics or in-situ radiations within the subcontinent. One exception is the Western Ghats biodiversity hotspot, an isolated mountain range with many endemic species. Understanding the origins of the montane-restricted species is crucial to illuminate both taxonomic and environmental history. Results With evidence from genetic, morphometric, song, and plumage data, we show that two songbird lineages endemic to the Western Ghats montane forest each have diversified into multiple distinct species. Historically labeled as single species of widespread Asian genera, these two lineages are highly divergent and do not group with the taxa in which they were previously classified but rather are distinct early divergences in larger Asian clades of flycatchers and babblers. Here we designated two new genera, the Western Ghats shortwings as Sholicola and the laughingthrushes as Montecincla, and evaluated species-limits to reflect distinct units by revising six previously named taxa and describing one novel species. Divergence dating showed that both these montane groups split from their Himalayan relatives during the Miocene, which is coincident with a shift towards arid conditions that fragmented the previously contiguous humid forest across peninsular India and isolated these lineages in the Western Ghats. Furthermore, these two genera showed congruent patterns of diversification across the Western Ghats Sky Islands, coincident with other climatic changes. Conclusion Our study reveals the existence of two independent endemic radiations in the high montane Western Ghats or Shola Sky Islands with coincident divergence times, highlighting the role of climate in the diversification of these ancient lineages. The endemic and highly divergent nature of these previously unrecognized species underscores the dearth of knowledge about the biogeography of the Asian tropics, even for comparatively well-known groups such as birds. The substantial increase in the diversity of this region underscores the need for more rigorous systematic analysis to inform biodiversity studies and conservation efforts. Electronic supplementary material The online version of this article (doi:10.1186/s12862-017-0882-6) contains supplementary material, which is available to authorized users.
Collapse
Affiliation(s)
- V V Robin
- National Centre for Biological Sciences, TIFR, Bellary Road, Bangalore, 560065, India. .,Present address - Indian Institute of Science Education and Research Tirupati, Mangalam, Tirupati, 517507, India.
| | - C K Vishnudas
- National Centre for Biological Sciences, TIFR, Bellary Road, Bangalore, 560065, India
| | - Pooja Gupta
- National Centre for Biological Sciences, TIFR, Bellary Road, Bangalore, 560065, India
| | - Frank E Rheindt
- Avian Evolution Lab, Department of Biological Sciences, Faculty of Science, National University of Singapore, Singapore, 117543, Singapore
| | - Daniel M Hooper
- Committee on Evolutionary Biology, University of Chicago, Chicago, IL, 60637, USA
| | - Uma Ramakrishnan
- National Centre for Biological Sciences, TIFR, Bellary Road, Bangalore, 560065, India
| | - Sushma Reddy
- National Centre for Biological Sciences, TIFR, Bellary Road, Bangalore, 560065, India. .,Biology Department, Loyola University Chicago, Chicago, IL, 60660, USA.
| |
Collapse
|
21
|
Robin VV, Vishnudas CK, Gupta P, Ramakrishnan U. Deep and wide valleys drive nested phylogeographic patterns across a montane bird community. Proc Biol Sci 2016; 282:rspb.2015.0861. [PMID: 26085588 DOI: 10.1098/rspb.2015.0861] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Montane species distributions interrupted by valleys can lead to range fragmentation, differentiation and ultimately speciation. Paleoclimatic fluctuations may accentuate or reduce such diversification by temporally altering the extent of montane habitat and may affect species differentially. We examined how an entire montane bird community of the Western Ghats--a linear, coastal tropical mountain range--responds to topographic valleys that host different habitats. Using genetic data from 23 species (356 individuals) collected across nine locations, we examined if different species in the community reveal spatial concordance in population differentiation, and whether the timing of these divergences correlate with climatic events. Our results reveal a nested effect of valleys, with several species (10 of 23) demonstrating the oldest divergences associated with the widest and deepest valley in the mountain range, the Palghat Gap. Further, a subset of these 10 species revealed younger divergences across shallower, narrower valleys. We recovered discordant divergence times for all valley-affected montane birds, mostly in the Pleistocene, supporting the Pliestocene-pump hypotheses and highlighting the role of climatic fluctuations during this period in driving species evolution. A majority of species remain unaffected by valleys, perhaps owing to geneflow or extinction-recolonization dynamics. Studying almost the entire community allowed us to uncover a range of species' responses, including some generalizable and other unpredicted patterns.
Collapse
Affiliation(s)
- V V Robin
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bellary Road, Bangalore 560065, India
| | - C K Vishnudas
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bellary Road, Bangalore 560065, India
| | - Pooja Gupta
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bellary Road, Bangalore 560065, India
| | - Uma Ramakrishnan
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, Bellary Road, Bangalore 560065, India
| |
Collapse
|
22
|
Robin VV, Gupta P, Thatte P, Ramakrishnan U. Islands within islands: two montane palaeo-endemic birds impacted by recent anthropogenic fragmentation. Mol Ecol 2015; 24:3572-84. [DOI: 10.1111/mec.13266] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Revised: 06/03/2015] [Accepted: 06/04/2015] [Indexed: 11/29/2022]
Affiliation(s)
- V. V. Robin
- National Centre for Biological Sciences; Tata Institute of Fundamental Research; Bellary Road Bangalore 560065 India
| | - Pooja Gupta
- National Centre for Biological Sciences; Tata Institute of Fundamental Research; Bellary Road Bangalore 560065 India
| | - Prachi Thatte
- National Centre for Biological Sciences; Tata Institute of Fundamental Research; Bellary Road Bangalore 560065 India
| | - Uma Ramakrishnan
- National Centre for Biological Sciences; Tata Institute of Fundamental Research; Bellary Road Bangalore 560065 India
| |
Collapse
|
23
|
Sridhar H, Srinivasan U, Askins RA, Canales-Delgadillo JC, Chen CC, Ewert DN, Gale GA, Goodale E, Gram WK, Hart PJ, Hobson KA, Hutto RL, Kotagama SW, Knowlton JL, Lee TM, Munn CA, Nimnuan S, Nizam BZ, Péron G, Robin VV, Rodewald AD, Rodewald PG, Thomson RL, Trivedi P, Van Wilgenburg SL, Shanker K. Positive relationships between association strength and phenotypic similarity characterize the assembly of mixed-species bird flocks worldwide. Am Nat 2012; 180:777-90. [PMID: 23149402 DOI: 10.1086/668012] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
Competition theory predicts that local communities should consist of species that are more dissimilar than expected by chance. We find a strikingly different pattern in a multicontinent data set (55 presence-absence matrices from 24 locations) on the composition of mixed-species bird flocks, which are important subunits of local bird communities the world over. By using null models and randomization tests followed by meta-analysis, we find the association strengths of species in flocks to be strongly related to similarity in body size and foraging behavior and higher for congeneric compared with noncongeneric species pairs. Given the local spatial scales of our individual analyses, differences in the habitat preferences of species are unlikely to have caused these association patterns; the patterns observed are most likely the outcome of species interactions. Extending group-living and social-information-use theory to a heterospecific context, we discuss potential behavioral mechanisms that lead to positive interactions among similar species in flocks, as well as ways in which competition costs are reduced. Our findings highlight the need to consider positive interactions along with competition when seeking to explain community assembly.
Collapse
Affiliation(s)
- Hari Sridhar
- Centre for Ecological Sciences, Indian Institute of Science, Bangalore, India
| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
24
|
Robin VV, Sinha A, Ramakrishnan U. Ancient geographical gaps and paleo-climate shape the phylogeography of an endemic bird in the sky islands of southern India. PLoS One 2010; 5:e13321. [PMID: 20967202 PMCID: PMC2954160 DOI: 10.1371/journal.pone.0013321] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Accepted: 09/13/2010] [Indexed: 11/21/2022] Open
Abstract
Background Sky islands, formed by the highest reaches of mountain tracts physically isolated from one another, represent one of the biodiversity-rich regions of the world. Comparative studies of geographically isolated populations on such islands can provide valuable insights into the biogeography and evolution of species on these islands. The Western Ghats mountains of southern India form a sky island system, where the relationship between the island structure and the evolution of its species remains virtually unknown despite a few population genetic studies. Methods and Principal Findings We investigated how ancient geographic gaps and glacial cycles have partitioned genetic variation in modern populations of a threatened endemic bird, the White-bellied Shortwing Brachypteryx major, across the montane Shola forests on these islands and also inferred its evolutionary history. We used Bayesian and maximum likelihood-based phylogenetic and population-genetic analyses on data from three mitochondrial markers and one nuclear marker (totally 2594 bp) obtained from 33 White-bellied Shortwing individuals across five islands. Genetic differentiation between populations of the species correlated with the locations of deep valleys in the Western Ghats but not with geographical distance between these populations. All populations revealed demographic histories consistent with population founding and expansion during the Last Glacial Maximum. Given the level of genetic differentiation north and south of the Palghat Gap, we suggest that these populations be considered two different taxonomic species. Conclusions and Significance Our results show that the physiography and paleo-climate of this region historically resulted in multiple glacial refugia that may have subsequently driven the evolutionary history and current population structure of this bird. The first avian genetic study from this biodiversity hotspot, our results provide insights into processes that may have impacted the speciation and evolution of the endemic fauna of this region.
Collapse
Affiliation(s)
- V V Robin
- National Institute of Advanced Studies, Indian Institute of Science Campus, Bangalore, India.
| | | | | |
Collapse
|