Answer:
The light gray lines are showing the predicted change in temperature for the habitat. For example, in the salamander's column, it shows the predicted temperature range being from about 7.5-12 degrees. This means that the temperature will CHANGE about 7.5-12 degrees. Another example for the light gray bar is the tree frog's change. The gray bars are predicting the temperature change to be about 9.5 - 11.5 degrees.
The black lines are showing what temperature change the species can adapt to. For example, the tree frog's temperature change resistance is from about -5 - 2 degrees. The Red-tailed hawk's temperature change resistance is about -3 - 3.