critical aspect of healthy ecosystems

Worksheet: Species abundance vs. Biodiversity

Worksheet: Species abundance vs. Biodiversity

Biodiversity is a critical aspect of healthy ecosystems. This should not surprise you, since foodwebs are so interconnected, and diversity brings a sort of built in resilience to any ecosystem. However, because energy is limited, any habitat or ecosystem can only support a limited number of organisms. In any habitat or ecosystem, you can have one of two extremes on a continuum. Either there are many individuals of one species present (abundance) or there are some individuals of many species present (biodiversity). Usually, it falls somewhere in between.

One fairly constant variable is the degree of human intervention. Areas influenced and controlled by humans tend to be lower in biodiversity than natural areas. To illustrate this, you are going to do a simple ecological comparison between a natural area and a man-made area. The natural space can be anything, as long as it is not regularly mowed, watered, or managed by humans. An abandoned field will do, or a riverbank that looks “wild.” If you are unsure, check with your instructor. The manmade area can be your front lawn, a golf course, etc.

I. Choose your habitats, then describe them below. Include photos.

A. Natural Habitat:

B. Managed Habitat:

II. Area delineation: You will need to determine how you are going to define your study areas. This is important so that you can make sure that you don’t examine a larger area in one place and therefore skew one of your variables. One easy way is to take a metal coat hanger and stretch it out into a circle. Then, lay that down in each area and count the organisms you find just within that circle. Anything will work, as long as it will allow you to ensure equal study areas in each space. When you get to your area, toss the hoop or whatever your measuring device is and study the area it lands on. This will help ensure that you aren’t selecting areas more or less diverse and thus introducing an element of bias into your study.

A. Describe your method of measuring study space.

B. Calculate the study area (If using a circle, the formula for area is Πr2)

C. Even though the metric system is widely accepted in most sciences, please convert your answer from Part B above to square feet.

III. Species Tally: You will not be expected to identify species, however you can differentiate between different species just by looking at them. For instance, you may see three different types of grass. While you may not know their names, you know that one has broader leaves, one has hairier leaves, and the other has thinner spikey leaves. As you go through your study area, Fill in the table with descriptions so that you can keep your species separate in your mind. You should add more rows as necessary to each table!

**Be sure to provide data information from your worksheet on the Q&A Forum**

A. Natural Habitat: Species

Species #



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