By: David Frye

Ecological Concepts & Field Observations

Succession: a stereotypical series of changes in the composition and structure of an ecological community through time (Withgott and Brennan, 2009).

The continued change of an ecological community that is driven by climate, community structure, and disturbance.

Ecological Succession

How do you determine if the community structure is appropriate for the area you are

observing?

Black Cottonwood Pacific Willow

- comparing mature species to new growth can be helpful

What are some good indicators that the campus wetlands are following a healthy successional path?

Western Red Cedar saplings

- through research determine what the apex species is

- go into the field and see if that species is present

Species Diversity: the number and variety species in the world or in a particular region (Withgott & Brennan).

How many different types of species are in the area being studied.

Species Diversity

How important is canopy cover to species diversity?

No canopy cover Limited diversity

- in a wetland ecosystem canopy can greatly influence diversity

- the less canopy there was, the less species diversity was present

How important is canopy cover to species diversity?

Increased canopy cover More diverse species community

- in the campus wetlands heavier canopy cover usually led to greater species diversity

Disturbance: a temporary change in average environmental conditions that causes a pronounced change in an ecosystem (“Disturbance” 2010).

Natural occurrences (people often view as destructive) that help to shape the physical form and the diversity of an ecosystem.

Ecological Disturbance

Are the disturbances in the campus wetlands helping drive succession and

diversity?

Cut bank

- cut banks help to establish new habitat for aquatic species

Are the disturbances in the campus wetlands helping drive succession and diversity?

Beaver landscape management

- forest canopy is being reduced- invasive species are able to re-establish themselves

Are the disturbances in the campus wetlands helping drive succession and diversity?

Area where trees have been blown down by the wind

- in established forests blow down areas create opportunities for new species to flourish - uprooted trees create microclimates which increase species diversity- once again, it may help invasive species to become established reducing diversity

Nutrient Cycling: nutrients move through ecosystems from one reservoir, to another, remaining for varying amounts of time (Withgott & Brennan).

Nutrients, such as nitrogen, move in complex cycles through ecosystems which sometimes make them available for living organisms to take up and use for production.

Nutrient Cycling

Is there evidence that nutrient cycling is working in the wetlands?

Decomposing logs and leaves

- decomposition is a good visual indicator that nutrients are being cycled

- decomposing materials allow their nutrients to re-enter the cycle for other organisms to potentially use.

Is there evidence that nutrient cycling is working in the wetlands?

Fungus growing on a dead branch

- the presence of detritivores, such as fungus, are a good sign that decomposition is happening properly

Disturbance. (2010). Wikipedia. Retrieved April 7, 2010, from http://en.wikipedia.org/wiki/Disturbance

Withgott J. and Brennan S. (2009). Essential Environment: The Science Behind the Stories, 3rd Edition. Pearson Education Inc. San Francisco, CA.

Works Cited