The Macroecology of Indian Pollinators: Patterns, Processes and Future Implications

Kallivalappil, Ratheesh (2021) The Macroecology of Indian Pollinators: Patterns, Processes and Future Implications. PhD thesis, University of Lincoln.

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The Macroecology of Indian Pollinators: Patterns, Processes and Future Implications
PhD Thesis
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Abstract

Pollination is a key ecosystem service and vital step in the reproduction of most angiosperms.
Therefore, the endangerment and extinction of pollinator species collapse the complex ecological
networks and hence threaten both agriculture and biodiversity. A large proportion of the human
diet depends directly or indirectly on animal pollination. Both invertebrates and vertebrates
pollinate a variety of angiosperms. While much research has been focused on insect pollinators,
the role of vertebrate pollinators is not as widely recognized. Vertebrates pollinate a variety of
plants including economically important crop species in tropical countries and many of these
plants are either completely or partially dependent on pollinators for fruit/seed production.
Therefore, declining pollination services in these tropical cultivated goods may result in
substantial losses in revenue. Here, my project investigates the extinction risk of global and
Indian vertebrate pollinator species using the IUCN extinction risk assessment method. The
potential pollinator species have been identified from various primary, peer-reviewed literature
sources. I compiled a dataset consisting of 1,554 and 99 vertebrate pollinator species for the
globe and India respectively. Additionally, the project explores the economic value of pollination
services for Indian vertebrate pollinators.
The results for the global extinction risk show asymmetric patterns of threat within the vertebrate
groups. Globally, mammal pollinators were more highly threatened than the bird and reptile
pollinators, though there were large-scale population declines experienced across all pollinator
groups. The narrow ranged pollinators experienced large-scale threat and population decline
relative to broad ranged pollinators. Hotspots of threat for vertebrate pollinators are shown in the
Andes of South America, Madagascar, and south-eastern Australia. The interactive effect of body
mass and body length and significant phylogenetic signal along with various external
anthropogenic factors show the extinction risk in global pollinators are a combined effect of both
intrinsic biological traits and extrinsic anthropogenic factors across multiple scales.

The extinction risk assessment for Indian pollinators show mammals are the only pollinator group
threatened with extinction. But both bird and mammal pollinators face population decline, a
similar trend reported for the global pollinators. Like global pollinators, the population decline is
higher in narrow ranged pollinators than the broad ranged pollinators. Body size does not predict
threat and population decline in Indian pollinators, a contradictory result to the global pattern.
Absence of phylogenetic signal in threat and population decline show they are evolutionarily not
predisposed to extinction. Like global pollinators, most Indian pollinators appear to be threatened
by agriculture and biological activities. The value of vertebrate pollination services is estimated to
be £2.85 million (₹28.2 crores) and the contribution of bird pollinators are higher than mammal
pollinators. The study also highlights the beneficial role of bat pollinators to the Indian economy
and biodiversity. Thus, it emphasizes the need for the Government of India to revoke the status
of fruit bats as vermin and list them as protected in the Schedules of Indian Wildlife Protection
Act, 1972.

Keywords:pollination, ecology, angiosperm, extinction, Vertebrates, Invertebrates
Subjects:C Biological Sciences > C181 Biodiversity
C Biological Sciences > C100 Biology
Divisions:College of Science > School of Life Sciences
ID Code:48517
Deposited On:10 Mar 2022 16:03

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