The Importance of Native Species, and A Case for Exotic Ones
Words: Tanisha Singh, UG’22
Illustrations: Vernika Mrig, UG’23
This article is brought to you by The Edict, in collaboration with Tarang, the Environment Ministry at Ashoka University. The Edict is committed to a more environmentally conscious readership, and together with Tarang, we aim to offer more coverage towards that end. We believe it is necessary for environment and climate issues to warrant greater and better journalism in order to spark conversations long overdue, about the world we live in. This collaboration is our attempt towards the same.
As the 20th century gave way to the 21st, humankind has been continuously reminded of the great importance biodiversity has for the welfare of the planet, all ecosystems and the living organisms that inhabit them, including humans themselves. Our actions during the previous century devastated the environment with an intensity and pace almost defiant of the possible consequences that ambush us even today. The key to all life, as we now know, lies in the preservation and balanced functioning of the intricate web of ecosystem links that bond all species to one another. The species found naturally in any ecosystem are those that are native to it, while those that are introduced to ecosystems are considered foreign or exotic species.
Over the course of several millennia, native plant species and wildlife have evolved together to adapt to environmental conditions, such that they are reliant on each other for many functions. From fulfilling their nutritional requirements and providing wildlife with safe shelters, predator hideouts and breeding grounds to enabling other ecosystem processes essential to life and regulating climatic conditions, native flora plays a crucial role in the maintenance and survival of the ecosystem it belongs to. The species in an area belong as much to the area as the area does to them- that is to say, the species present in a given geographical location are characteristic of it, but only so because they are adapted to the conditions on account of several years of survival, possible near-extinction and evolution.
Upon considering the various benefits of native species, it almost seems counter-intuitive to remove them from an area, and replace them with foreign varieties. However, the introduction of exotic species is something that humans have been doing for centuries, and not just with plants, but wildlife as well. While generally exotic species are introduced intentionally, there are several prominent cases of foreign plant species being introduced to new locales by virtue of them being unknown stowaways on trader fleets and even human clothing!
For the species that are introduced generally, the reasons are manifold: economic gain, better yield, recreational (hunting, fishing of wildlife) and aesthetic purposes (ornamental flowers and vegetation), and to battle nostalgia by immigrants missing their homelands. When exotic species are introduced, there are three possible outcomes- either the species does not survive the different terrain and climatic conditions, or the species survives, in which case it either serves its purpose and becomes a harmonious component of the native landscape, or it becomes invasive and threatens other native vegetation via competition for resources and space. It is the latter that is largely responsible for the bad reputation exotic species have, because the damage that they cause is often widespread and irreversible to a large extent, as when any species is introduced, the other species responsible for keeping its growth in check are not introduced alongside it. This often results in the invasive species having the freedom to multiply rapidly, as it possesses none of the threats it did in its native locale.
Even so, exotic plants are not as uncommon as one would think them to be. In India, the case of Tagetes, genda or marigold serves to evidence this. Native to the Latin Americas, marigold was introduced to Spain, from where it spread further throughout Europe and Africa. During the colonial era, the Portuguese brought it to India, and now it is one of the most commonly found flowers, and occupies a prominent position in several Hindu festivals and celebrations. Many might not even be aware of its exotic origins, because of its widespread use and the manner in which it has seamlessly become a part of the native landscape. Similarly, when it comes to other plants and culinary spices, such as black pepper, tomatoes and red chilies, which are now commonly used in several preparations across India, few would think that they were introduced, and not local.
Let’s bring this entire discourse a little closer home- think of our campus. At Ashoka, when it comes to major or larger types of vegetation (trees and shrubs, for example), the native vegetation forms the majority in terms of number of species, but the minority in terms of total cover, relative to the exotic species present. Most of the native species are found around the periphery (read: around the sprinting track that encircles the perimeter of campus), forming part of the Aravalli shelter belt. The rest of the areas, including the much-loved mess laws, mostly comprises exotic species. Several flowering plants on campus, with the exception of fruit trees such as jamun, mango, papaya, fig and pomegranate, are also exotic. Of course, the fact that native vegetation will always serve more ecological functions, be better adapted to its surroundings (and the wildlife that inhabit it), and require less specialized care is undeniable. This begs the question- why have exotic species at all?
Most native trees on campus, such as neem, have deciduous life cycles, so their leaves brown and fall off annually. Opposed to this, exotic species like silky oak generally have evergreen life cycles, and so their foliage remains vibrant and green all year around. Not only does this add to the visual beauty of the landscape, it also means that maintenance is easier as there’s a lot less shedding. As for the flowering plants, most of them are either pure exotic species, or hybrids between two different exotic species- the huge marigolds on campus, for example, are a hybrid between African and French varieties. This is because they are bred with the intention of cultivation, and flower reliably for longer durations. Their bold hues and strong fragrance also serve as an asset when considering the influence on the aesthetics of their surroundings, but also more frequent pollination. Additionally, some native species that are so well adapted to the climate and terrain on campus, that they grow rather aggressively (the trees around the Sports Block are a great example), and so require frequent pruning; this is not seen with any of the exotic species. There is also the occurrence of naturalised species i.e. species that are non-native, but very well adapted to the native climate, and do not need help in propagation. The frangipani (locally known as champa or chameli) and Delonix regia (or gulmohar) trees on campus fall under this category. Naturalised species are also mostly compatible with the wildlife in their area- and this is especially advantageous, given that most native animal species obviously prefer native trees over exotic ones.
While it may be tempting to selectively consider the disadvantage exotic species pose to native landscapes, and the possibility of them turning invasive, the truth is that with thorough planning and management, exotic species have a lot to offer. That being said, native species form an irreplaceable part of the ecological systems they belong to, and the several purposes they serve cannot be compensated for at all. However, this does not mean that a compromise between native and non-native flora is impossible-the Ashokan campus is evidence to the fact that there is enough room for both types of species to exist in one landscape harmoniously.
The author would like to thank Soham Kacker from the Biology Society and Mr. Ranjeet Parmar for their detailed inputs and taking the time out to answer her questions.