ENVIRONMENTAL ACTIVITIES SITE

Designing a Nature Preserve

(Adapted from an activity created by K. Winnett-Murray, Biology Dept., Hope College)

One way to help preserve biodiversity is by the creation of nature preserves. The location and design of preserves is a critical factor in maintaining the Minimum Viable Population (MVP) of any particular organism needing protection. A nature preserve can be thought of as a habitat patch  or island and there are three guiding principles (derived from the theory of island biogeography) that help planners arrive at the best design: the species-area relationship, the avoidance of edge effect, and freedom to migrate. This exercise introduces you to some of the techniques used to measure biodiversity, the relationship between habitat patch size and species diversity, and the relationship between sampling effort and species diversity (the species-area curve relationship).

The question you’ll be investigating in this exercise is: Is it better to have one large reserve or several smaller ones?

Materials

  • Hula hoop - about 80 cm diameter.
  • Embroidery hoop - about 16 cm in diameter.
  • Data sheets, graph paper, pencil, and clipboard.

Procedure

  1. Find a patchy lawn, meadow or weedy area (somewhere where the two hoops will lie relatively flat when you throw them, so you can record the plants and animals inside the hoop).
    hula hoop and embroidery hoop
  2. Close your eyes and throw the hula hoop at random. On your data sheet record all living things inside the hoop (record the type of organism and how many there are). It’s not critical that you identify all the species, but you need to be consistent in the name you assign an organism, so you can make sure you record it in the same way, each time you observe is. So, you could, for example, label something “shiny, black beetle, approx. 2mm” and record all occurrences of that particular organism.
  3. Repeat the activity at least five times (so you’ll have at least six samples for the hula hoop).
  4. Repeat the activity with the embroidery hoop (at least six samples).
  5. Calculate the average number of organisms in the hula hoop (count the total number of organisms in each hoop and divide by the number of hoops) and do the same for the embroidery hoop. Compare the total number of living things in the big “preserve” with the number in the little “preserve.”
  6. Calculate the average number of the different kinds of organisms in the hula hoop (count the number of different kinds of organism (species) in each hoop and divide by the number of hoops) and do the same for the embroidery hoop. Compare the number of different organisms in the big “preserve” with the number in the little “preserve.”
  7. Plot the cumulative number of species types found on the y axis, and the number of plots sampled on the x axis. This is the species-area curve. It shows the importance of sample size, among other things. If this results in a graph that goes up, then levels off, it means that you are not finding any new species as you increase the number of samples. (If you are able to plot this graph in the field, and find your graph is still rising, you can take more samples). How many hula hoop samples does it take to reach this point? How many embroidery hoop throws? What would you predict?
  8. Measure the diameter of your two hoops and calculate the area of each of your hoops (“preserves”): Area = pr2.  Divide the area of the hula hoop by that of the embroidery hoop to find out how many embroidery hoops you would need to make up the area of one hula hoop :

    Hula hoop (80cm diameter): Area = p * 40 * 40 = 5026.55 cm2

    Embroidery hoop (30 cm diameter): Area = p * 15 * 15 = 706.86  cm2

    5026.55/706.86 = 7.11

    The hula hoop area is approximately seven times bigger than the embroidery hoop area.

    Now consider the question of whether it is better to have one hula hoop-sized preserve or seven embroidery hoop-sized preserves. Which system would you expect to have the greatest variety of species? Explain your reasoning.

  9. Write up your experiment in a brief report. The report can be written in a standard form (Introduction, Methods, Results, Discussion). For some more detail on writing scientific reports the following site is useful:

    http://www.unc.edu/depts/wcweb/handouts/lab_report_complete.html

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