Invasive plants, pests choke off biodiversity

Invasive plants, pests choke off biodiversity

In 1997, when researchers from the Ashoka Trust for Research in Ecology and the Environment (ATREE) began studying Lantana seagulla in the Biligiri Rangaswamy Temple (BRT) Tiger Reserve in Chamarajanagar, an invasive weed from tropical America was beginning to spread.

Today, the weed has become the dominant species, not only in the BRT reserve, but in lakhs of hectares of deciduous forest and forest savannah vegetation of Karnataka.

Lantana are species of animals, plants and other organisms introduced to new areas by human activities. They thrive on the value of native and perennial plant species. Invasive species have been identified as the second biggest threat to biodiversity, after habitat destruction.

Shivanna Muttegowda (65) remembers the forests of the BRT reserve as lush green in monsoon and ash in summer. Now, the situation has changed. He lives in Kanneri colony, K Gudi village.

The grass under it would dry up and catch fire. But even in the middle of summer, we used to see green leaves for a few days without the help of anything but dew. For the past 20 years, Lantana has blanketed the BR Hills. “One spark can set the whole forest on fire,” Mettegowda said.

“Studies across BRT land in 1997, 2008 and again in 2018 showed that Lantana went from being 5% to 30% of all woody plants at the expense of native plants,” said Ancila Hiremath, a botanist. and environment and senior assistant at ATREE.

Ankila said Lantana has replaced BRT’s conservation vegetation as the dense weed area has modified the open savannah forest. “This has changed the nature of the habitat and the quality – the forests cannot move under large herbivores. The desirable grass has been replaced by the undesirable Lantana. Research has shown that Lantana competes with natural species such as amla, an important product of the non-wood forests, thus affecting the way of life of the community. which depends on the forest like Soligas,” he added.

Experts from the Wildlife Institute of India (WII) reported in 2020 that Lantana has taken up 44% of India’s forests. Weeds, however, are only one piece of the puzzle, as Euopatorium, Senna spectabilis, acacia and Ballari jali (Prosopis juliflora) have destroyed the biodiversity of deciduous forests and grasslands. The Center for Environmental Management and Policy Research, which reviewed the Jindal company’s 24-km long mining project at Toranagallu in Ballari, found that Prosopis juliflora and parthenium had invaded 1.6 km of forest area along the project.

Economic impact

On September 5, the Intergovernmental Science Policy Platform on Biodiversity and Ecosystem Services (IPBES) warned that IAS is responsible for 60% of recorded animal extinctions in the world. The economic impact of this loss is also significant. Around 37,000 IAS in the world were causing an annual loss of Rs 42,300 crore as of 2019.

Ecologist and biologist Alok Bang, who wrote a study estimating that the damage caused by IAS could impact India’s economy to the tune of $127 billion over the past 60 years, said it was a fraction of the actual cost. The researchers used INVACOST, a database that involves systematically retrieving, combining and measuring the reported economic costs of IAS.

“We are only counting the costs of peer-reviewed written claims. In fact, we have only built on the top. This is clear when we consider that India has reported only about 300 IAS compared to the 3,000 IAS reported by France. Indian ecologists and biologists have a long way to go. they have to go in understanding and reporting, said Bang, faculty at Azim Premji University.

This ecological and economic impact will only grow if there is no intervention, said KV Sankaran, an expert on invasive species and coordinating lead author of the IPBES report. “Our estimates show that costs due to IAS have increased fourfold every decade since 1970. It is also estimated that the number of exotic animals will increase by 36% in 2050 (compared to 2005 figures) if we do not take the necessary control measures. ,” he said.

Accelerating global economies and drastic changes in land and sea use are creating fertile ground for IAS. Climate and population factors also help those species to gain strength in this ecosystem. Costs will be significantly higher in 2023 compared to 2019. Invasive species and their negative effects will only increase if the necessary measures are not adopted quickly.

Home to a rich flora and fauna, the country’s natural habitats have provided direct (forest products) and indirect (fodder and water) benefits and services (climate regulation) to millions of people for generations. As invasive species erode this diversity, the main victims are vulnerable people such as forest dwellers, farmers and fishermen.

For example, in the case of Soligas, researchers from ATREE have noticed that apart from the visible impacts on life, invasive species also greatly affect the well-being of society. “Our work with Soligas tells us that the invasion of Lantana has made forests a dangerous place for people by reducing visibility and increasing opportunities to encounter wildlife,” Ankila said.

As a result, over time, these invaded lands have reduced people’s access to important cultural sites, and younger generations are growing up far from the forests, their traditional knowledge and culture, he added.

Data from the Forest Department shows that the total number of human-animal conflicts – from crop and cattle loss to accidents on both sides – has doubled in 10 years from 20,244 in 2013-14 to 40,258 in 2022-23 in the country. As the IAS also provides protected areas for wildlife, the conditions may increase further.

Prevention methods

Bang said identifying and classifying IAS can only happen when academics begin to look at the problem. “For example, a pest in an agricultural plant can be identified, but to describe it as an IAS, a domain expert with knowledge of invasive species should be involved,” he said.

The researcher added that it is safe to assume that most of the IAS have not been identified. “This is worrying because the delay in implementation will lead to cost overruns,” he said.

Sankaran identified the root of the problem as the lack of policy to monitor the IAS. “Only 17% of countries around the world have national laws or regulations to deal with invasive alien species. And 45% of all countries have no investment in alien species management,” he said.

Officials agreed that prevention is better than control in the case of invasive species. “We need nearly thirty thousand rands (R30,000) per hectare to remove Lantana, plant natural grass species and manage it for the next two years. The whole process is very slow compared to the speed of invasive weeds that spread like wildfire,” said Subhash Malkhede, Principal Principal Conservator of Forests (PCCF), Wildlife.

Former PCCF BK Singh noted that human activity within natural forests was the first driver of IAS. “The natural ecosystem has been disrupted by deforestation and fire, paving the way for IAS. Some of the Lantana areas in Bandipur, BRT and Nagarahole are so dense that even elephants cannot walk through them. We need to prevent diversion and fragmentation of forests to better protect habitats,” he said.

A common issue

The problem is not limited to forests – agriculture, horticulture, animal husbandry and fishing are already among the emerging problems. An example of this is the fall armyworm, a native of America, which has killed corn and other crops. In India, it was reported for the first time in Karnataka in May 2018. In August 2019, researchers observed its presence in the entire country, except Jammu and Kashmir.

During their research, SS Deshmukh and others from the University of Agriculture and Horticultural Sciences, Shivamogga, and the International Maize and Wheat Improvement Center in Nairobi, Kenya, surveyed 150 smallholder farmers and found that the cost of farming had increased. Rs 3,600 per hectare as they have invested in more pesticides. “These additional costs are huge for small, disadvantaged landowners. Maize yields in 2020 were largely the same as in 2017, but crop protection costs per hectare during the season increased 10 times in 2020,” they concluded.

Specifically, they noted that the use of pesticide frequency increased significantly from “0.10 spraying pesticides each time in 2017 to 2.10 applications”, an increase of 2000%.

On the other hand, the Center told the Rajya Sabha last year that 40% to 80% of the chilli crop in Telangana and Andhra Pradesh was destroyed by an invasive pest called Thrips parvispinus, also known as the Southeast Asian thrip. “Excessive use of chemical pesticides and planting of crops may be the reasons for the outbreak,” the government said, citing expert reports.

Of the 300+ species reported as IAS in India, about 99 are marine and 19 are those that invade freshwater have been identified by the Zoological Survey of India. The effects of their influence are evident. The IPBES report mentions the displacement of native mussels and oysters caused by Caribbean false mussels, a development that directly affects fishermen.

Climate change

Exacerbating this situation is climate change, which makes ecosystems more vulnerable to invasive alien plants by reducing the resistance of native species to invasion. “There are many complexities that make it difficult to predict the full impact. Climate change can interact with exotic plants and cause wildfires. The movement of certain IAS plants from low-lying areas to high-lying areas, which we have witnessed in India, is proof of the impact of IAS,” said Sankaran.

In its commitment to combat climate change, India announced at the Paris Conference (COP 21) a target to create carbon sinks of 2.5 to 3 billion tons of CO2. This means that it is promising to increase the forest area to 33% of the total land area, from the current 21%.

In July, more than 400 environmentalists against the Amended Forest Conservation Act wrote in a letter to the Center that commercial plantations, forest fragments and urban parks “can never replace the ecological functions of intact natural forests”. Domain experts have warned that clearing the barriers will lead to more deforestation, diversion of forests and disturbance of natural habitats.

As governments reinforce the conservation model, where value is attributed to ecosystems only if they benefit people, the importance of biodiversity has taken a back seat. Bang noted that understanding the importance of biodiversity, regardless of immediate social benefits, was a key step in the conservation and protection of the IAS. “Protecting the natural ecosystem should be a step to prevent the loss and extinction of local and existing plant species. It has to be seen outside the frame of reference,” he said.

#Invasive #plants #pests #choke #biodiversity

Leave a Reply

Your email address will not be published. Required fields are marked *