Scientists studied a species of termite and looked at their foraging habitats across the United States. The termite’s population in a given tree was measured by the level of decomposition within a tree, due to the termites eating the bark. The experiment also kept track of the level of shade tolerance for each species of tree. For the species of trees in this experiment, shade tolerance fell into two main categorizes- shade tolerant (ST) and intermediate shade (IS). Lastly, they recorded the average amount of rainfall in that given month for the species location being observed. The chart below summarizes the data. Scientists hypothesized that the level of decomposition would be highest in tree species with a higher average rainfall. In addition, they hypothesized that the trees allowing more shade would allow for more termites and, in turn, more decomposition.
| | Tsuga canadensis | Morus rubra | Pinus strobus | Acer rubrum | Arbutus menziesii | Quercus lobata | Juniperus scopulorum | | | ------------------------------ | --------------- | ----------------- | --------------- | --------------------- | ------------------ | ------------------------ | ----- | | Decomposition (in ccm) | 2.38 | 3.21 | 1.01 | .970 | 2.89 | 1.31 | 4.03 | | Shade tolerance | ST | ST | IS | IS | ST | IS | ST | | Average rainfall | 47.27 | 50.89 | 43.26 | 41.65 | 46.87 | 44.98 | 52.75 |
The relationship between average rainfall and the quantity of termites in a certain tree species is that __________