Ecosystem engineers are organisms that modify their environment. They increase biodiversity by creating habitat for species other than themselves. The oak apple, caused by a tiny wasp called Biorhiza pallida, is just such an engineered environment.

Ecosystem engineers

Ecosystem engineers are organisms that modify their environment. They increase biodiversity by creating habitat for species other than themselves. The oak apple, caused by a tiny wasp called Biorhiza pallida, is just such an engineered environment.

These are spangle galls on an oak leaf.

Ecosystem engineers are organisms that modify their environment. They increase biodiversity by creating habitat for species other than themselves. The oak apple, caused by a tiny wasp called Biorhiza pallida, is just such an engineered environment.

There are silk button galls on the underside of oak leaves all over the park.

There are silk button galls on the underside of oak leaves all over the park.