Ecological Restoration Chapter 10 Ecological Restoration

The Balance of Nature An environmental myth that states that the natural environment, when not influenced by human activity, will reach a constant status, unchanging over time. Environmentalists in early 20th cent. Formalized the idea Succession proceeds to a fixed, “classic” condition called Climax Condition (steady state stage that can persist indefinitely, max. organic matter, max. storage of chemicals, max. biodiversity.

Restore to what !! Restore to original natural, permanent condition. But…. What is this? This idea assumes that nature is constant. Nature is NOT constant; it undergoes change Some species require change to persist

What needs to be restored? Wetlands, Rivers and Streams (Ex: Kissimmee River) Channelization of the river, Prairie Restoration (Ex: Allwine Prairie) Agricultural conversion

The Process of Ecological Succession The process of the development of an ecological community or ecosystem. Two Types: Primary Succession: The initial establishment and development of an ecosystem (following volcanic activity or edges of glaciers) Secondary Succession: The reestablishment of an ecosystem where there are remnants of a previous biological community (following a natural disaster: hurricane, flooding, fire)

Patterns in Succession An initial kind of vegetation specially adapted to the unstable conditions Small plants and other early-successional species grow and seeds spread rapidly. Larger plants and other late successional species enter and begin to dominate the site. A mature forest develops. (Succession is usually characterized as early (steps 1&2), middle and late.) Examples of Succession: Dune Succession, Bog Succession, Old-Field Succession

Bog Succession

Succession and Chemical Cycling Biomass, production, diversity and chemical cycling change during succession Biomass and diversity peak in mid-succession, increasing at first to a maximum, then declining and varying over time.

Species Change in Succession Earlier and later species in succession may interact in three ways: Facilitation Interference Life history differences If they do not interact, the result is termed chronic patchiness

Facilitation During succession, one species prepares the way for the next (and may even be necessary for the occurrence of the next) Dune and bog succession

Interference During succession, one species prevents the entrance of a later species into an ecosystem. Ex) Some grasses produce dense and thick mats so the seeds of trees cannot reach the soil to germinate

Life History Difference The difference in the life histories of the species allow some to arrive first and grow quickly, while others arrive late and grow more slowly Ex) seed disbursal