COMMUNITY ANALYSES
GENERAL ECOLOGY LABORATORY

Location: Lake Winona

Objective: To assess the aquatic invertebrate community structure in a lake littoral zone

Hypothesis: Invertebrate community diversity does not differ betwen east and west lake littoral zones

Agenda:

1) Collect 3 samples of invertebrates from both east lake and west lake littoral zones.

2) Return samples to the lab and separate invertebrates from the debris.

3) "Identify" and count invertebrates from each sample.

Analysis:

1) Create a table displaying taxa and numbers of invertebrates for all samples.

2) Calculate a Simpson's diversity index (p. 179, equation 6) and a Shannon diversity index (p. 180-181, equation 16) for each of the 6 individual samples.

3) Compare diversities of samples from the east and west lakes using standard t-tests (Simpson's vs. Simpson's, Shannon's vs. Shannon's, p. 11, equation 10).

4) Calculate a Bray and Curtis index of community similarity (p. 190, equation 7) comparing the 3 east lake samples combined with the 3 west lake samples combined.

Equipment:

Dip nets, Waders, Buckets, Sorting pans, Dishes, Forceps, Eyedroppers, Dissecting needles, Lights, Dissecting microscopes, Taxonomic aids