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Why we need ‘Ecosystem Engineers’

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 By Maneka Gandhi
The Kerala Government has brought in sharp shooters to kill a tiger in Pathanamthitta. The tiger has allegedly killed one person, a person who tried to stop it from killing the cattle tied up near the human settlement. By the time this article comes out, the young tiger will probably have been shot dead. For no fault of his.
The authorities and forest department have been on a rampage for six months killing wild boars in Pathanamthitta at the behest of farmers. The tiger has nothing left to eat. So, now, he attacks cattle. In every single place where tigers have supposedly become maneaters – whether Chandrapur, Yawatmal or Pilibhit, it is because the wild boars have been systematically killed for months before that.
The most foolish thing that governments can do is to kill the wild boar. They are the main ecosystem engineers in India. Not only are they the prey of large cats, the wild boar, because of their large size and frequent rooting for food, have a significant effect on the forest floor. They disturb the soil, creating ideal conditions for the germination of seedlings. They also help to disperse seeds because these often pass intact through their digestive tract and are pushed into the soil. One of their most useful functions, and the reason that we are particularly interested in the species, is that they eat bracken or coarse ferns which no other species can digest. They also dig it up for bedding material. This stops it from spreading across the forest floor and preventing the growth of seedlings. Insect larvae, earthworms, and snails are usually the staple food in the diet of the wild boar.
But farmers keep complaining about the increase in wild boars. And the reason for that is because governments have systematically killed all the wolves. In the 1990s, an illiterate posing as a Chief Wildlife Warden (after retirement he boasted of the number of elephants and tigers he had killed during his tenure) ordered the killing of the last wolves in Uttar Pradesh. So, boars have few predators left.
Nature is so convoluted that each thing ties into another. You harm one creature anywhere and its repercussions are felt at the other end of the world. Just as the wildlife markets, and the disgusting food habits of the Chinese in one city, have led to this worldwide pandemic of viruses.
Let me give you a few pathways that nature takes.
The Bahamas are islands and, like all islands, they will sink as the oceans rise. So many islands have already quietly slipped into the ocean like Dwarka – two from Sundarbans have gone in the last ten years. They need to be protected from high tides, from erosion of the bottom and sides. Most of these islands are protected by mangroves, the magical trees  that line the coasts with their roots in the waters and prevent the seas from gobbling the land up by holding the soil in place and protecting the land from storms. You see them in Goa – you used to see them in Gujarat but 87% have been removed because one company needed to earn money through making ports that no one uses. They are being cut in Tamil Nadu and Kerala. At a time when most countries are replanting them, we have not replaced a single one. It is amazing that we have not recognised that this is the main keystone species that keeps the world intact. Mangroves are also the nursery for all fish. So, no mangroves, no fish or sea animal. If politicians want to benefit the fishermen community, the first thing they could do is to replant and protect mangroves.
Anyway, mangroves need fish urine to survive. According to a study done by University of Michigan, in the journal Science Advances, about the mangroves in the Bahamas, large fish such as snappers roam the mangroves looking for food. They urinate through their gills and the urine contains nitrogen. This nitrogen  fertilises the mangrove trees and algae growing on their roots so they can grow lush and feed the fish, crabs, and other animals. These sea creatures are caught to feed people.
But snappers are the most popular victims for the sport of spearfishing and for anglers throughout the Caribbean. The biggest fish, the ones with the most beneficial effect on the mangroves, are the ones that are usually caught for the dinner table. The study estimated that if 50 percent of the snappers were caught by fishermen the amount of nitrogen in the mangroves would decrease by 69 percent. The mangroves would dwindle, and the island will submerge faster. In the meantime, the fish will all disappear.
There are thousands of other cases where one species shapes the surrounding ecosystem. These species are called ecosystem engineers. Ecosystem engineers are “organisms capable of controlling the availability of resources for other organisms by modifying the physical environment”.
For instance, the beaver makes dams in small rivers. Once their dams are built and water pools come into being, the landscape changes and a new ecosystem is born with different amphibians, fish and birds.
African Savanna elephants are the biggest boon for tree dwelling lizards. When they break twigs and branches, they leave crevices in the trees. These crevices become the homes and breeding places for tree lizards. Tree lizards eat insects like termites and spiders and are in turn eaten by other lizards and snakes.
Asian elephant dung piles not only act as nutrients for plants and fungi but, surprisingly, dozens of different species of frogs are found in them. They are accompanied by beetles, ants, spiders, centipedes, crickets: a whole world in itself according to a study “Shit Happens to be Useful! Use of elephant dung by Amphibians” in the journal Biotropica!
The most famous animal engineers are the wolves of Yellowstone Park. In the 1930s, all the wolves of the park were shot dead. The consequences? The elk populations in the national park increased and they ate all the undergrowth of the area stripping it bare. Riverbeds were targets and their juicy grass, and saplings disappeared. This desolate landscape did not even provide enough food for the birds, so they left. The beavers, who depend on the tree saplings on the riverbanks, disappeared. The elk ate all the juicy berries, so the trademark of the area, the bears, got much fewer. Without any vegetation to hold them in, the rivers broke their banks and started flooding the area. The park was an utter mess with very few species in it.
In 1995, wolves caught in Canada were released in Yellowstone Park. The elk population reduced, and they stopped coming out freely to the riverside because they were scared of the wolves. The willow and poplar saplings grew back and within a few years the riverbanks became stable again. The beavers returned and created little ponds with their dams. The amphibians returned and so did the birds. The bears are in better health.
The wolves are now, unfortunately, being shot again by illegal ranchers who farm their cattle near Yellowstone Park and want the park destroyed so that their cattle can have more place to feed. From 147 wolves, there are now only 100 left. And as they diminish, the park will go back to being a mess again.
How long will it take humans to learn a simple lesson- that interfering with a species for no reason and with an astounding lack of knowledge, leads to a problem with every other species as well?
(To join the animal welfare movement contact gandhim@nic.in, www.peoplefor animalsindia.org)