Native tree species are climate resilient, maintain ecological balance

Introducing exotic species and promoting monoculture plantations in forest areas, village common lands have caused disastrous impacts on the ecology and socio-economic condition of local communities

By Ravi Shankar Behera, Ranjit K Sahu
Published: Tuesday 13 August 2019
Cyclone Fani uprooted lakhs of trees in Odisha. Photo: Arabinda Mahapatra

There is an instinctive bond between humans and other living systems. People have an affectionate bond with nature. However, human priorities are known to be self-centred, and do not often consider factors that does not involve them directly. Environment is not a priority for them. 

In the age of industrialisation, people are conditioned to behave towards rapid development, or in any way improve financially. Because of rapid growth of humans, rewards have been given to those famous for contributing to the development of the economy, but passionate environmentalists are less recognised. Hence, more and more people are prone to make economy as a priority, more than the environment.

Forests and natural habitats have been exterminated to make way for urban developments, forcing the wildlife to be homeless and find other places to live. Although most species die when their habitat gets destroyed, some venture to different regions for their survival. This is especially so for birds, which fly to different regions and live.

Exotic species

Similar has been the case with plants and trees. Over the last three decades, government (forest department) has engaged in intentional import of exotic species, promotion of monoculture plantations and introduction of new species in forest areas, village common land for afforestation and plantation drives.

This has been an ecological and socio-cultural disaster! As the environment is assumed to be not a priority for most people, little care is given to whether a foreign species will bring damage to the existing ecosystem.

Exotic species like Acacia mangium, Eucalyptus, Simaruba glauca, Cassia siamea, Jatropha curcas etc, have been legally or illegally used extensively as plantations along roadsides or avenues or for promoting agro-forestry or farm forestry systems, etc.

Sometimes these introductions are calculated, but more often than not, most are based on departmental priorities or personal gains, including the raising of a certain species of saplings like teak, sal etc. This has led to disastrous impacts on the local ecology, environment and socio-economic impacts on local communities.

The recent severe Cyclone Fani that caused extensive damage to the trees and ecosystem in Odisha is a typical example. Fani uprooted and damaged millions of trees, leading to serious environmental and socio-economic challenges to the local communities, the biodiversity and local weather. It has also exposed the region to extreme climatic variabilities.

However, interestingly native tree species survived the onslaught of the cyclone as compared to the exotic species. This provides an important cue for the government and the state forest departments to undertake afforestation or plantations of native tree species along the coasts in consultation with local communities and civil society organisations.

New species are always unpredictable. They pose a threat to those who frequent its habitat. When a new species is introduced, the balance is disrupted. If the new species is a predator, then the population of the prey will decrease as there are more predators now, including the native ones.

If the introduced species is a herbivore, then the amount of plants will decrease. New species also compete with native species for land, water, and food. If the introduced species is stronger than the native ones, they could also replace the native species in the ecosystem. Foreign species may also carry diseases that can harm the native species.

However, this can also be seen as a positive effect. Sometimes, the introduced species help to regain balance in the ecosystem by altering the population of some of the native species. For example, the ecosystem may have originally not been in balance, with one or two overpopulated species. To solve this problem, species can be introduced to reduce the population.

However, more often than not, introduced species bring more harm than good. These species are commonly known as invasive species, which can have damaging effects on the environment they are introduced to. The effects can be diverse, affecting the local ecosystem, mankind and even the economy to a certain extent.

Although most introductions of species are a result of man’s intervention, some can be attributed to natural causes as well. Just like how you would take all things in moderation, constantly introducing species to an ecosystem forces it to change to regain the balance it had before. And if it fails to do so, it may collapse.

Effect on ecosystem

The biggest effect of exotic species is on the ecosystem. There is a lot of focus about ensuring balance in the ecosystem. This means a right amount of each of the species in the system for it to survive and sustain. There needs to be a right amount of predators for preys and right amount of plants for the animals to eat. This ‘right amount’ is the balance that we refer to in an ecosystem.

Ignorance is one of the reasons for the spread of exotic species. People need to understand about exotic species, their impact, and what can be done about it. The take-home message would be that every species belongs somewhere and you should never mess with the balance of nature by introducing non-native species into any region.

After the severe cyclone, the Government of Odisha and the state forest department have decided to undertake a massive afforestation drive by planting 130.50 lakh trees, spending 188 crore in the states’ coastal districts in collaboration with the local communities, general public, village committees, educational institutions and voluntary organisations.

Such mass plantations should invariably consist of native trees species, which are more climate resilient and adaptable to the local agro-ecological conditions.

A few native tree species in eastern Odisha and along the eastern coast  could include species such as Azadirachta indica (Neem), Alstonia scholaris (Chatiyani), Mimusops elengi  (Baulo), Tamarindus indica (Tamarind), Syzygium cumini (Jamun), Cryota urens (Royal Palm), Wrightia tinctoria, Butea monosperma (Palash), Shorea robusta (Sal), Pterocarpus marsupium (Pia Sal), Saraca asoca (Ashoka), Memycylon edule, Anogiessus latifolia (Bandhono), Terminalia arjuna (Arjuna), Lagerstroemia spp., Ougenia oojeinensis, Ficus arnottiana, Cassipourea ceylanica, Ficus benjamina, Bombax ceiba (Boll Cotton), Eugenia jambolana (Gulab Jamun), Mangifera indica (Mango), etc. Creepers such as Bauhinia vahlii and Acacia pinnata and also of the wild grass called babe (Eulaliopsis binata),

Mangrove associates, such as Aegiceras corniculatus, Excoecaria agallochSalvadora persica, Pongamia pinnataColubrina asiatica, Capparis roxburghii, Macrotyloma ciliatum, Avicennia officinalis, Avicennia alba, Aegiceras corniculatum, Ceriops decandra, Acanthus illicifolius, Bruguiera gymnorrhiza, Excoecaria agallocha and many others are also a part of the natural ecosystem in coastal Odisha.

Some of these tree species need to be raised by the Forest department and planted consciously. Watch and ward need to be ensured for the proper growth of the saplings. This can be done in collaboration with the local communities.

Other technical and policy level interventions could include increasing the gap between trees for unhindered movement of wind at high speeds.

More emphasis must be given on planting native trees with small leaves; planting trees such as Acacia and Eucalyptus should be avoided as they are harmful for the groundwater level. 

School children and youth must be oriented on the importance of native trees, especially on their importance in socio-economic and cultural value, better adaptability to local agro-ecological conditions, weather and resilience to climate variability and natural disasters like cyclones, floods and drought, provision of food, fibre, fuel, fodder and other ecosystem services. They should be motivated to plant native tree species in their schools, villages, towns and cities.

(Views expressed are the authors' own and doesn't necessarily reflect that of Down To Earth)

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