Problem 2
One technique for estimating the springtime abundance of sheep ticks in Scotland is by dragging a wool blanket over the grass. (Ticks will cling to anything that brushes against them during the spring.) Does this technique measure absolute density or relative density? How might you determine this?
Problem 8
The life table and the seed production of the winter annual plant Collinsia verna for \(1983-84\) was as follows (Kalisz 1991 ): $$\begin{array}{lccc} \hline & & \text { Average no. } \\ & \text { Age interval } & \text { Number } & \text { seeds produced } \\ \text { Life cycle } & \text { (months) } & \text { alive } n_{x} & \text { per plant } b_{x} \\ \hline \text { Seed } & 0-5 & 23,061 & 0 \\ \text { Seedling } & 5-7 & 6019 & 0 \\ \text { Overwintering } & 7-12 & 4617 & 0 \\ \text { plants } & & & \\ \text { Flowering } & 12-13 & 2612 & 0 \\ \text { plants } & & & \\ \text { Fruiting plants } & 13-14 & 692 & 10.754 \\ \hline \end{array}$$ Calculate the net reproductive rate for these plants and discuss the biological interpretation of this rate.
Problem 9
Forest ecologists usually measure the size structure of a forest and less often make use of the annual rings of temperate-zone trees to get the age structure of the forest. What might one learn from determining age structure in addition to size structure in a forest stand?
