What do we call organisms that cause drastic changes to the landscape, creating a new ecosystem?

Organisms that cause significant alterations to their environment, leading to the formation of new ecosystems, are referred to as ecosystem engineers. These are typically species that modify, maintain, or create habitats, impacting the availability of resources for other organisms.

For instance, beavers are a classic example of ecosystem engineers; they build dams that create wetlands, which can change water flow and provide habitats for a variety of aquatic and terrestrial species. The changes they make fundamentally alter the landscape, promoting biodiversity and creating habitats that support other forms of life.

In contrast, keystone species play a crucial role in maintaining the structure of an ecological community but do not necessarily create or alter ecosystems in the way ecosystem engineers do. Dominant species are those that are more abundant or have a larger biomass in an ecosystem but do not inherently change the landscape. Foundation species are similar to keystone species but primarily refer to those that provide important structural habitat, rather than creating new ecosystems.