Perennial Plants

One of the reasons that hardwood forest plant communities are dominated by perennial species is that these forests are generally very stable through time. So the plants don’t have to deal with wild fluctuations in conditions. Therefore, perennials have an advantage because the plant can store energy into its root structures and roots then use that energy more efficiently to grow and persist through time. This is particularly true for spring ephemeral species that begin growing very early in the spring to take advantage of the sun breaking through the leafless trees. Spring ephemerals will grow, flower, produce seeds, and die back by the time the trees start leafing out and the summer plants start coming up.

However, if conditions in an ecosystem change often from one time to the next, then being an annual can be advantageous. Annual plants grow, flower and produce seeds rapidly and the seeds can wait until conditions are good again. Desert flowers are examples of this since they can only survive during a short period each year when there is rain. Biennials (plants that grow, flower, reproduce and die in a 2 years) try to reach the middle ground and are well adapted for habitats that are somewhat variable but not extremely changeable from one time to the next, like old fields and edge habitats.

So, if you take plant species that are adapted for very reliable and constant conditions and change the environment radically and do it very fast, as is the case when earthworms invade… what would you expect to happen to those plants?