What Makes a Healthy Ecosystem

Floods! Tornadoes! Fires! Disease! The animals and plants in any ecosystem have to deal with a lot of challenges. A healthy and intact ecosystem is adaptable and can bounce back from terrible natural disasters, changes, and challenges.

BIODIVERSITY

A biodiverse ecosystem is home to many different types of animals, plants, and other living things. Biodiversity is the most important factor in having a strong and healthy ecosystem. When an ecosystem is biodiverse, wildlife have more opportunities to obtain food and shelter. Biodiversity also means a more complex food web, and more “paths” for matter to cycle, decompose, and create top soil for new plant growth.

Different species also react and respond to changes in their environment differently. For example, imagine a forest with only one type of plant in it, which is the only source of food and habitat for the entire forest food web. Now, there is a sudden dry season and this plant dies. Plant-eating animals completely lose their food source and die out, and so do the animals that prey upon them. But, when there is biodiversity, the effects of a sudden change are not so dramatic. Different species of plants respond to the drought differently, and many can survive a dry season. Many animals have a variety of food sources and don’t just rely on one plant. Now our forest ecosystem is no longer doomed!

Changes, disturbance, or even disasters in nature are inevitable. Some disturbances will deeply affect an ecosystem and can thin out or kill off a species of microbe, plant, or animal. But an ecosystem with intact biodiversity will have many other species that can survive, allowing the ecosystem as a whole to bounce back. The less biodiversity there is, the weaker an ecosystem is.

NICHE

A living thing’s role in an ecosystem—what its habitat is, and how it gets food, reproduces, and interacts with others—is its niche. If two different species have the same niche, then they are in direct competition. As in any competition, only one can dominate, and the losing species will die out if they do not change or adapt.

KEYSTONE SPECIES

Certain ecosystems have a type of animal or plant that almost the entire community depends on directly or indirectly. If a keystone species population is reduced or compromised, it could mean the end of an entire ecosystem. It is important for us to identify and protect these important keystone species.

SPECIES EVENNESS

What would happen if there were more wolves than rabbits in the forest? The wolves would eat all the rabbits before the next generation of rabbits could be born. Species evenness between predator and prey stops this from happening. If any living thing higher on the food chain outnumbers its food source, then a whole species could be eaten to extinction. By measuring species populations, ecologists can make sure that an ecosystem is balanced and intact.

Animals on the same trophic level also need to have species evenness between each other. If there are too many rabbits in an ecosystem, there may not be enough grass for other primary consumer species to survive. Also, if a disease (like rabbit fever) hits and there is only one species (rabbits in this case) on a trophic level, then all of the larger predators will die out too, because they have no other food source. Understanding species populations lets people hunt in ways that actually benefit an ecosystem. Maintaining species evenness is crucial to maintaining biodiversity.

If there are too many limiting factors in an ecosystem—like predators, lack of resources, bad weather, or disease—then a population will die out completely. If there are not enough limiting factors and life becomes too easy for a species, then a population will boom out of control. This can lead to one species outcompeting all other living things until the biodiversity of the region is destroyed and resources are overused or even depleted.

EDGES

The edges of an ecosystem are just as important as its core parts. The area where two distinctly different biomes or ecosystems blend together is called an “ecotone.”

You may have seen an ecotone where a forest blends into grassland, or where the bank of a river divides the water from the land. These ecotones blend two different biomes together but also act as a border, repelling and attracting different types of animals. Ecotones protect the mainland from erosion, protect core ecosystems from invasive species, and provide certain animals with unique resources. Often ecotones are the perfect places for hiding, reproducing, or protecting baby animals before they fully mature and enter their main habitat.

Some animals and plants have evolved to live only in or very close to ecotones. They are called “edge species.” The other species that can live only in the core of an ecosystem depend on the edge as a border. All core ecosystems are surrounded by some kind of ecotone or edge region. When people construct roads or buildings without considering the crucial edges of ecosystems, they can shrink and damage the core wilderness more than they intend.