Question

what type of functional response do wolves have on caribou density?

Caribou density (number/km^2) Number of caribou killed per wolf (per day) Proportion of caribou killed per Wolf (per day 0.1 0.5 0.2 0.7 0.9 18 0.9 +2.5 02 0.95 0.98 0.22 1.5 2 1.01 1.02 1.03 0.15 0.1 0.07 0.05 0.04 2.5 1.03 0.5 Number of caribou killed per wolf (per day - -Proportion of caribou killed per wolper day Sheet1 Sheet2 Sheet

Answer 1

For this you have to ay atention on a value that is not on the graph: caribou density. Let us make a graph for that and see the behavior:

Caribou wolf relation - Caribou density Caribou density/Caribouskilled per wolf Number of carbou killed per Wolf 1 2 3 8 9 10 4 5 6 7 Measurements

Now we can compare the behavior of the curves compared to the other curve.

I understand the caribou density is the independet variable (as the values increase steadily). We then have to focus on the orange curve (caribous killed per wolf) which is the wolf behavior. We can see a tendency in increasing the caribous killed per wolf as the caribou density increases, but note that there is a maximum point for this caribou killing values. Even when the density is still increasing, the wolves don't kill any more caribous and stabilize the curve.

That explains why the proportion of caribou killed per wolf curve tends to decrease. The wolves stop killing a bigger number of caribous while the density keeps increasing, that leads inveitably to a hard drop in the proportion killed curve (we can see this in your first graph).