Answers to Hone Your Problem-Solving Skills Questions
1. NPP should increase following the disturbance, reaching a maximum somewhere during the intermediate stages of succession, and then decrease at late stages as the forest matures and consists of old-growth stands of trees.
As a result, nutrient losses should be lowest during the intermediate stages of succession, highest just following the disturbance, and intermediate late in succession.2. Nutrient losses should vary according to their importance to plant growth. Limiting nutrients, such as N, will be retained more with lower losses than nutrients that are not limiting growth. Elements that are not taken up by plants should be lost at the same rate throughout succession.
3. The results support Vitousek's hypothesis regarding the patterns of nutrient loss between intermediate and late stages of succession. For nutrient elements, losses are generally higher in late successional communities than in intermediate-stage communities. In particular, N is retained much more than the other elements, suggesting it is probably the nutrient limiting growth of the plants. Elements such as Na and Cl, which have little or no importance to most plants, are lost at the same rates in intermediate and late stages of succession.