Summary

If we were managing the whooping crane population, the model would help us determine the impact of changing the environmental and demographic factors affecting whooping cranes. We illustrated three examples to show how the model can help decision-making. In order to make a more clear example, we tried to keep the model simple and used just a few of the parameters available and we changed those singly.

Global Change effect

With the continuation of global warming, the climate will have greater variability. The growth in population growth rate is sensitive to the variability in climate. Because we are unaware of the true value of the standard deviation in growth rate we explored the entirue range of possible values. At larger values for standard deviation, the program models an increase in the occurrence of catatrophic events. Small values for standard deviation model few catastrophic events. The figure shows that the crane  population is quite vulnerable relatively moderatechanges in climate. Risk of falling below 20 individuals increases sharply once it surpasses a relatively low value of the standard deviation in growth rate (R).

Management Options

Upon establishing a baseline standard deviation of 0.25, we chose two management scenarios. In an effort to increase survival of the species, we decided to simulate the effects of (1) changing the habitat and (2) founding a new population.

We found that enhancing habitat did not help the population very much.  The model does provide evidence that establishing a new population would be a possibility in which to invest.

The general public can assist in crane protection and research through the Adopt-A-Crane program. A donation will assist the effort to help the cranes and give the donator the title of "crane parent". Donations enhance habitat, assist enforcement and lobby efforts, and support research efforts.
 

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The Woodrow Wilson National Fellowship Foundation CN 5281, Princeton NJ 08543-5281 - Tel:(609)452-7007 - Fax:(609)452-0066 Technical contact: lpt@woodrow.org