Digital Radio-Telemetry Monitoring of San Nicolas Island Foxes

摘要

The island fox has been designated a conservation focus by the U.S. Navy. Because of the species unique evolutionary history, it is highly susceptible to threats from novel predators and disease. High fox densities on San Nicolas Island make this population particularly vulnerable to disease epidemics. Since an epidemic or novel predator can effect populations over a short time period, annual surveys and monitoring may not be enough alert managers about onset of potentially catastrophic declines. Daily, weekly, or monthly survival monitoring of wildlife populations is typically conducted using radio telemetry. Though telemetry is quite effective, it is also quite expensive, particularly in terms of labor costs. Even the most intensive monitoring, however, is only effective if results are tied to management actions. Appropriate responses to monitoring results must balance the need to respond to real threats against the cost of false alarms. This balance is best achieved through the use of a tiered response system based on observed increases in mortalities during a short time period.