MODELING THE EFFECTS OF PREDATOR EXCLOSURES ON A WESTERN SNOWY PLOVER POPULATION

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.     

使用除法算法对里德-所罗门编码进行解码

里德-所罗门编码是最广泛使用的纠错码之一.介绍一种使用除法算法的解码方法,发展该算法的理论并讨论支持该算法的例子.最后,证明与该解码算法有关的一个概率上的定理,关于何时该方法是最有效的,得出一些概率上的结果.