SEE-UBiosphere2

General Methadology for Instructors and TAs

Exercise 13: Do Roads Affect Biodiversity?
Module 13: Habitat Fragmentation and Deforestation

Background Lecture

Instructor gives biological background on the forms of habitat fragmentation, some of their effects on biodiversity, and results that others have found.

  1. Roads have several impacts on biodiversity
  2. The impact of roads on biodiversity tends to be greatest immediately at roadside and then decrease rapidly, although roads do have an effect several hundred meters into the forest
    1. At road sides the habitat is drier, hotter, brighter (more sun), more open, windier, and there is a different plant community there than deeper into forests

Student Pre-field Preparation

Activities in the experiment

Hypotheses to test (two sets)

  1. Roads negatively effect overall insect biodiversity (richness and abundance) in desert ecosystems (biodiversity should be lowest in sampling points closest to the road)
    1. Ha: Overall insect biodiversity is either not affected or is increased as a consequence of roads being present
  2. Road surface, traffic intensity, and road width mediate the influences of roads (as all three increase in human development, biodiversity should decrease)
    1. Ha: Road surface, intensity, and width either do not have an effect on biodiversity, or insects are more diverse in the transects nearest the high intensity roads

Independent variables in the experiment

  1. Road condition
  2. Distance from road
  3. Plants from which the insects are collected

Dependent variables in the experiment

  1. Species richness
  2. Average per species abundance
  3. Overall insect abundance
  4. Taxon specific richness
  5. Taxon specific abundance
  6. Simpson diversity index
  7. Shannon-Wiener diversity index
  8. Jaccard similarity diversity index
  9. Morisita-Horn similarity diversity index

Student Evaluation