MODELING THE EFFECTS OF PREDATOR EXCLOSURES ON A WESTERN SNOWY PLOVER POPULATION
Article first published online: 20 JUL 2012
©2012 Wiley Periodicals, Inc.
Natural Resource Modeling
Volume 25, Issue 3, pages 529–547, August 2012
How to Cite
WATTS, C. M., CAO, J., PANZA, C., DUGAW, C., COLWELL, M. and BURROUGHS, E. A. (2012), MODELING THE EFFECTS OF PREDATOR EXCLOSURES ON A WESTERN SNOWY PLOVER POPULATION. Natural Resource Modeling, 25: 529–547. doi: 10.1111/j.1939-7445.2012.00131.x
- Issue published online: 1 AUG 2012
- Article first published online: 20 JUL 2012
- Received by the editors on 30th June 2011. Accepted 20th April 2012.
- Discrete-time stochastic model;
- Nest exclosure;
- Western snowy plover
Abstract In Humboldt County, California, nest exclosures were used between 2001 and 2006 to reduce the predation of eggs aiding in the recovery of a threatened population segment of western snowy plovers (Charadrius nivosus). Due to a sudden increase in adult mortality in 2006, field biologists abandoned the use of nest exclosures. This paper describes a discrete-time stochastic model designed to compare two different management strategies (with and without exclosures) to predict the change in the plover population. The model uses beta distributions to model demographic parameters, and whenever possible, these distributions were fit to survey data of these populations. The model shows nest exclosures to be effective in increasing chick fledging rates. However, the model also shows that an increase in adult mortality potentially caused by the nest exclosures would counteract this increase in fledging rates. The model predicts that there will be a net negative effect on the population if these exclosures reduce adult survival to 90% of its unexclosed rate. The model also demonstrates that the population is dependent on immigration.