Hello and welcome back to our blog. Today we are going to know about very important animals to our ecosystem “The Megaherbivores”. So, why are they so important? What impact do they have in the ecosystem? What are the megaherbivores? But first, what is Herbivore?
What are herbivores?
An herbivore is an organism that mostly feeds on plants. Simply, herbivore are the animals who only eat plants. Now there are types of herbivores. Some herbivores consume a wide variety of plants, others consume specific plant parts or types. For example, frugivores eat fruit, granivores eat seeds, folivores eat leaves, and nectarivores eat nectar. Nectarivore is an animal which derives its energy and nutrient requirements from a diet consisting mainly of the sugar-rich nectar produced by flowering plants. Megaherbivores are simply herbivores of extremely large sizes, such as elephants, rhinos and gaurs.
What are megaherbivores so important for the global climate?
The global climate and biodiversity crises highlight the growing urgency to better understand the connections and interactions between the different parts of the Earth system. The Earth system consists of different spheres, such as the atmosphere, geosphere, hydrosphere and biosphere, that are all interlinked by dynamic and complex processes. A major disruption in the processes within one sphere can influence processes in other spheres and, therefore, affect the entire Earth system. The Earth’s biosphere has shaped the atmosphere and hydrosphere for at least 2.5 billion years. Large-bodied animals are increasingly recognized as playing important roles in the functioning of the biosphere and thus the Earth system.
There is an increasing interest in the ongoing effects of extant large-bodied animals on Earth system functioning. For example, mammals, as prime dispersers of seeds of certain hardwood tree species, importantly contribute to the carbon sequestration potential of tropical forests. Thus, a disruption in seed dispersal (a biosphere process) by defaunation can lead to changes in carbon sequestration (a process that intersects the atmosphere, biosphere and geosphere). Other recent examples of how extant large-bodied animals shape Earth system functioning include reindeer Rangifer tarandus grazing and trampling reducing shrub cover in the arctic tundra, thereby increasing surface albedo changing watershed chemistry and hydrology.
Herbivores have various physical features evolved specifically for their diet as well. Many herbivores have large, flat molars for grinding tough plant matter. Additionally, herbivores often have multiple stomach chambers and a specialized digestive system. For example, cows have a stomach with four chambers. The food a cow consumes first passes through two stomach chambers before returning to the mouth for additional chewing. This returned food is called cud. Once the cow rechews and swallows the cud, it passes through the third and fourth stomach chambers for further digestion.
What is the role of megaherbivores at an ecosystem level?
Herbivores play an important role in maintaining a healthy ecosystem by preventing an overgrowth of vegetation. Additionally, many plants rely on herbivores such as bees to help them reproduce. By the same token, herbivores rely on plants not just for food but also for habitats and shelter.
Herbivores also serve as a food source for carnivores, which are also ecosystem engineers. For example, in 1995, wolves were reintroduced into Yellowstone National Park to control the elk population. Through their overgrazing, the elk had damaged trees, increased erosion, and spoiled trout streams. In the following years, the wolves helped stabilize the elk population and restored balance to the Yellowstone ecosystem. It is for this reason, the UK is considering the reintroduction of both wolves and Eurasian lynx.
This megaherbivores are said to be the ecological engineers of our ecosystem because of their large size and strength and play a significant role in the lateral transport of mineral nutrients in an ecosystem, tending to translocate them from areas of high to those of lower abundance.
The presence of megaherbivores in a particular environment has many ecological functions including change in the structure of vegetation through feeding behaviour, destructive power, and seed dispersal, impacting on the recycling and spread of nutrients, as well as impacting on the climate. Because of the lifestyle of these giant animals, trees grew small and other plants had ample room and nutrients. In fact, grazing by herbivores has been responsible for fostering biodiversity through coevolution.
Elephants are the True Ecosystem Engineers!
As we know that the elephants are the largest herbivore in the world, they also function as keystone species. Keystone species, such as elephants, that regulate the ecological processes and interactions within ecosystems. Besides influencing their ecosystem, elephants help others thrive by shaping the landscape. Elephants consume large quantaties of plant material every day. As they munch on fruits, they pass seed through the digestive system and then drop them off in dung. This helps in seed dispersion and providing an opportunity for plants to colonize new areas. Other animals eventually benefit from this by having a new habitat and food source. In fact, elephant dung has many uses for both the natural world and for human society.
In overly scarce situations elephants dig natural water holes providing water not just to themselves but also to other animals. This helps other species fight off dry seasons for survival. There are close to a hundred species benefiting from elephants including the tiny dung beetle (which is from a larger and crucial ecosystem). Elephant dung plays a key role in nutrient recycling allowing speedy germination and growth, the dung betels make the dung reach soil layers. Conserving the elephant means conserving a whole umbrella species from the tiny lizard that builds its nest in the crevices of elephant-damaged trees to the grazing deer’s and other small herbivores rejoicing at the luscious open grasslands.
And other megaherbivores do the same for the ecosystem. Because of these large bodied animals our wildlife is intact.
Written by: Atharv Deshmukh
Concluusion
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