Overstory diversity in the Porcupine Mountains
Consider the following data collected from two different overstory communties.
|
Community |
Acer rubrum |
Acer sacchrum |
Tsuga canadensis |
Thuja occidentalis |
Ulmus americana |
Pinus strobus |
|
Floodplain |
5 |
0 |
3 |
3 |
2 |
3 |
|
Upland |
1 |
14 |
1 |
0 |
0 |
0 |
In this example, both communities have the same number of individuals (N=16). However, alpha diversity (number of species) is higher in the floodplain the upland community (5 versus 3 species, respectively). Evenness in the distribution of species is very different. The upland community is more likely to lose species because 2 out of 3 of the populations have very low numbers (less than those in the floodplain community). Beta diversity (species turnover) is also low, as there is a 33% change in species diversity from the floodplain to the upland communities in this example.