Hope and Biodiversity on the Andaman Islands

During the decade of 2012-2022, the Andaman Islands in the Bay of Bengal have become increasingly accessible. An archipelago once feared for its disrepute as a British penal settlement now evokes imageries of emerald-blue blissfulness. Better connectivity, enhanced infrastructure post the deadly 2004 tsunami, and increased local capacity to manage tropical diseases such as malaria have all contributed to the islands’ becoming a popular tourist destination. The islands are also coveted by another group of wide-eyed citizens, scientists. A part of the Indo-Burma biodiversity hotspot with high numbers of endemic species, the Andaman Islands’ biodiversity and geological history has attracted expeditioners, naturalists, and geologists alike. The past decade has thrown up several new and exciting biological discoveries from the islands — from new species to new behaviours, from applications of novel research approaches to uncovering new threats to biodiversity. I have had the privilege to witness this expansion of knowledge from the front row. And now is as good a time as any, to look back at these discoveries that have filled us with wonder, surprise, and an overwhelming sense of the undiscovered expanse beyond us.

The discovery of species new to science is an event that always captures the public imagination. The coming to light of a life form that had hitherto remained hidden from the human gaze sparks a sense of curiosity with a tinge of humility for our myopic understanding of the earth we inhabit. In 2016, herpetologists discovered the Andaman bush toad, which was not like anything known from the islands. A small toad perched on grass blades and leaves somehow managed to elude scientists for decades. This was accompanied by a plethora of new descriptions and rediscoveries of herpetofauna, including tree frogs, mangrove frogs, agamid lizards, and geckos. Several distinctive fish forms were also uncovered, that included a new species of moray eel, only the third known from Indian waters, and a stream-dwelling species of snakehead fish, named the Andaman emerald snakehead to capture its unique green colour. On Interview Island, better known for its feral elephant population, a limestone cave inhabiting shrimp with reduced eyes was discovered. It was named Ravi Sankaran’s cave shrimp in honour of the pioneer of cave research in the Andaman Islands. The azure lanternfly, found on buttressed tree trunks in evergreen forests, made a splashy entry to the already long list of newly discovered creatures.

The decade’ s discovery of tens of new species also brought with it a slew of fascinating new behaviours. Investigating the feeding habits of several species of frogs on the islands, my team found the mangrove frog’s almost obsessive dependence on fiddler crabs and witnessed the Indian bullfrog’s well-documented un-froglike consumption of a host of vertebrates, including birds and snakes. Gluttonous feeding in the animal kingdom must be followed by soothing siestas. Studying sleep behaviour in day-active lizards, we not only found an invariable dependence to sleep on thin plants that shake under the weight of any approaching predators but also that lizards could return with great precision to their previous sleep sites. This strong fidelity to safe sleep sites must entail a working memory of the surrounding space for these lizards.

To enable even more detailed investigations of nature, several new research techniques have recently been employed to study the biodiversity of the islands. The use of genetics to uncover historic evolutionary relationships and present-day population connectivity was seen in the case of bats, snakes, frogs, and geckos. Notably, this helped scientists identify how genetically healthy animal populations were, based on how well-connected they were to the rest of their populations. However, to truly understand the complexity of island life, researchers must find an ally in time. Long-term studies spanning decades can reveal much more than what a couple of seasons of studies would. Just five years of monitoring the stages and processes of an evergreen forest, from fruits to seedlings to adult trees, generated insights into how exactly a forest functions — remarkably, trees were shown to contract in periods of resource crunch. In common wisdom, the islands reveal themselves only to the patient and worthy. And no one knows this better than the researchers who have forged long-lasting relationships with the islands, some returning year on year for more than two decades.

Inhabitants of the Andaman Islands, settled onto the archipelago in several waves, have known the forests and seas around them personally. Community knowledge becomes truly powerful as collective knowledge is transferred from generation to generation. For example, the elusive bush toad discovered only in 2016 by scientists was well known to the Great Andamanese tribe. Honouring this, the scientists named the species epithet “beryet” after the local name in the Andamanese language, meaning small frog. Another curious case of communities beating scientists to new information was when Indian bullfrogs, not naturally occurring on the islands, were reported by scientists in 2013. Citizen science surveys of islanders later revealed the year of introduction to be 2000-2001 and helped reconstruct the frog’s invasion across several islands of the archipelago. This points to a need to carry out scientific surveys while tapping into and acknowledging existing community knowledge on nature (i.e., ethnobiology).

Will the Andaman Islands continue to throw up more surprises in the years to come? Well, yes. Researchers are limited in their capacity to discover, but the islands are not constrained in their ability to amaze — after all, they have had a few million years’ head start. A peril of modern-day research is also its biggest strength, its adherence to specific questions and rigid protocols. This can lead to blinkered vision in a rainforest. Sometimes, I wonder in how many ways the islands will surprise me in the future, and think of the time of early explorers — would they have thought of the questions we ask now? Will the future talk of the ecology of the 2010s as early discoveries that barely scratched the surface?

Not all recent discoveries bring hope, with new studies reporting a range of threats to the sacrosanct biodiversity of the islands. Microplastics were found in zooplankton, the primary consumers of marine systems. The source? Chipped paint from boats. Strains of the infamous and deadly chytridiomycosis fungus were discovered in frogs, although its ability to cause disease outbreaks that have led to population collapses of frogs elsewhere is yet to be ascertained. With increased trade and transport with the Indian mainland, the islands now receive a steady flow of non-native species that are introduced either intentionally or unintentionally. The list of recent entrants includes Mozambique tilapia, Indian bullfrog, common garden lizard, and likely a non-native rat.

As the current decade of research marches on in full swing, I can only look forward in hope and anticipation of the discoveries to come. Uncharted and underexplored regions of the islands, especially marine domains (including the deep sea), forest canopy, freshwater streams, and caves, are likely to surprise us many times over. The initiation of new programs such as the Automated Reef Monitoring System that promises to uncover patterns of coral settlement and survival, SeasonWatch that records tree flowering and fruiting every month, and studies that formally document community knowledge hold great potential. The past decade of biodiversity research on the Andaman Islands has given us many moments to exclaim and drop our jaws and even more reasons to harbour hope that the islands still have many secrets to reveal to us.