What is a Keystone Species?

Ecosystem Engineers

A keystone species, also known as a cornerstone or functional species, plays a crucial role in maintaining the structure, diversity, and health of its ecosystem. Much like the keystone in an arch, which holds all the other stones in place, these species hold ecosystems together. Their presence and activities have a disproportionately large impact on their environment, influencing the types and numbers of various other species in the ecosystem.

The wolf’s howl can be heard for miles, uniting the pack. © Steve Fehlberg

Creating a Balanced and Diverse Ecosystem

Keystone species can be plants, animals, or even microorganisms, but they all share the trait of being essential for the ecosystem’s stability. For instance, predators like wolves help control the population of herbivores, such as deer, preventing overgrazing and allowing vegetation to thrive. This, in turn, supports a myriad of other species, from insects to birds, creating a balanced and diverse ecosystem.

Similarly, beavers are a classic example of a keystone species. By building dams, beavers create wetlands that provide habitat for many other species, from fish to amphibians to birds. These wetlands also improve water quality and mitigate flooding, showcasing the far-reaching benefits of a single species’ activities.

Reintroduced in many areas, beavers are thriving once again. © critterbiz, Shutterstock

The loss of a keystone species can lead to significant and sometimes catastrophic changes in the ecosystem, often resulting in the decline or disappearance of other species. This makes their conservation critical for maintaining biodiversity and ecosystem health.

Understanding and protecting keystone species is a fundamental aspect of rewilding and conservation efforts. By supporting these vital species, we help ensure that natural environments remain resilient, vibrant, and capable of sustaining life. Embracing the importance of keystone species is embracing the intricate, interconnected web of life that sustains us all.