The Alligator Gar, a fish from the Americas, has been found in parts of India in recent years. Photo: iStock
The Alligator Gar, a fish from the Americas, has been found in parts of India in recent years. Photo: iStock

India needs a single, comprehensive policy to tackle invasive species: Ankila Hiremath

Down To Earth speaks to plant ecologist Ankila Hiremath as the IPBES gets ready to release its landmark report on invasive species

The Alligator Gar, a fish from the Americas, has been found in parts of India in recent years. Photo: iStock

Invasive alien species are one of the five major direct drivers of biodiversity loss globally, alongside land and sea-use change, direct exploitation of organisms, climate change, and pollution.

Target 6 of the recently adopted Kunming-Montreal Global Biodiversity Framework is to “eliminate, minimize, reduce and or mitigate the impacts of invasive alien species on biodiversity and ecosystem services”.

After four years of work, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) is all set to release its landmark report on invasive species that is expected to fill in substantial knowledge gaps on the issue.

Down To Earth caught up with senior plant ecologist Ankila Hiremath, affiliated with the Ashoka Trust for Research in Ecology and the Environment (ATREE), on what her expectations from the report are. Edited excerpts:

Rajat Ghai (RG): Do you think the world has ignored the issue of invasive species for too long?

Ankila Hiremath (AH): The issue of invasive species was really brought to our notice by a book that Charles Elton published in 1958. Even after that, it was only in the 1980s, after the SCOPE workshops, that there was collective recognition of invasive species as an issue of environmental concern. So, it is only since the 1980s that people have been concerned about invasive species.

But it has varied across regions. In places where invasive species have had a much greater impact, there has been a lot of work for quite some time. I refer to places like Australia, New Zealand, the islands of Hawaii. But in other places, people have woken up to these issues a little later than that.

RG: Can ecosystems that have borne the brunt of invasives brought on by colonialism like Australia or New Zealand ever recover and become pristine again?

AH: I don’t like the word ‘pristine’ because we don’t know what that is and it gets misunderstood. But no, I think your question about whether they can go back to a state pre-invasion is a valid one.

It is doubtful that these places can go back to a pre-invasion state. Remote oceanic islands like New Zealand or the Hawaiian Islands, have been particularly severely impacted by invasive alien species. Their native flora and fauna is unique and distinctive but also depauperate compared to mainland regions.

Take, for instance, the complete absence of predators and the evolution of flightless birds on these islands. So when predators like cats first arrived in places like this, such fauna became victims.

Some of these isolated islands had not previously been exposed to various kinds of pests and diseases which are common on mainland areas. The arrival of avian malaria, for instance, in Hawaii, wiped out a very large proportion of their bird species.

Trying to go back to some sort of a pre-invasion state is probably out of the question. I think the only possibility is mitigating the impacts of invasive species. And an acceptance that we may have to live with novel ecosystems, which are new assemblages of plants and animals that have never existed over evolutionary time.

RG: Invasives have a role to play in the raging wildfires that we see today in several parts of the world including Maui in Hawaii recently or California, Siberia and Australia in the recent past. Is there any truth in that statement?

AH: In Hawaii, it has been fairly clearly demonstrated that abandoned agricultural lands have been taken over by introduced pasture grasses, which are drought-resistant and highly flammable.

But I don’t think you can make that generalisation across the world. The other regions that you mentioned have been fire-prone in the past. But with changing climatic regimes, for example, with more frequent droughts, these areas have become more vulnerable to the occurrence of wildfires. Climatic factors are also compounded by altered fire regimes, such as fire prevention, which allows the build up of flammable fuels.

There is renewed appreciation for what traditional ecological knowledge regarding indigenous fire management could teach us about keeping fuel loads under control and preventing the outbreak of such wildfires.

Invasive species cannot be implicated in all these cases. But at the same time, invasive species can change fire regimes by altering fuel loads. Even in Indian ecosystems, where lantana has become widespread it builds up flammable biomass. In dry years, when lantana burns it causes very destructive wildfires, quite unlike the ‘cool’ surface fires that would have occurred prior to lantana invasion, due to burning of the grassy understory.

RG: India has had its own share of invasives: African catfish in our streams and prosopis juliflora, parthenum hysterophorus as well as lantana, which you study. How has our progress been so far on this issue?

AH: I think we have come to the party late, if you like. I think in India, although there has been awareness about invasive species, as a conservation or management issue, it has only come to be recognised in the last 10 to 15 years.

One of the targets under India’s National Biodiversity Action Plan (Target 4) is specifically focused on the prevention and management of invasive species.

But our efforts to tackle invasive species have so far been more reactive than proactive. For example, we are now conscious of the need to manage invasive species in certain habitats that are of high conservation value. But we do not have measures in place to prevent the arrival of new invasive species.

RG: What are your expectations from the IPBES report?

AH: This is probably the most comprehensive synthesis of global knowledge on invasive species. It brings together findings from across the world on different aspects of invasive species: their introduction, trends, impacts, management efforts, existing control measures, policies. For governments and policymakers, it is the best evidence that that is available currently.

I hope that this will enable us to make a fresh start in how we as a country manage invasive species. Currently, we invoke a number of existing legislations and policies to deal with invasive species, for example, the Environment Protection Act, the Livestock Importation Act, the Plant Quarantine Rules. But some of these existed before invasive species were ever recognised as an issue.

Also, responsibility is divided across many different government departments and agencies, for instance, the National Bureau of Plant Genetic Resources and Animal Genetic Resources that deal with quarantine issues are responsible for prevention of introductions. This creates challenges for a comprehensive approach to the prevention and management of invasive species.

We need a single comprehensive legislation devised specifically to deal with invasive species. And there needs to be a single nodal agency responsible.

Down To Earth