Todd Ewing

Using Changes in Naive Occupancy to Detect Population Declines in Aquatic Species; Case Study: Stability of Greenhead Shiner in North Carolina

SEAFWA Journal Volume 3, March 2016

Determining population trends for many aquatic species is problematic for most resource agencies because little or no historical information is available on population size nor are resources available for contemporary population estimates. Managers often only have available to them presenceabsence data collected by qualitative surveys conducted at intermittent intervals. Changes in naïve occupancy can be used to detect population trends. Naïve occupancy is the ratio of number of sites where a species is detected to total number of sites surveyed, without correcting for imperfect detection...


Comparison of Two Objective Protocols used to Determine the Status of North Carolina Aquatic Species

A primary responsibility of wildlife resources agencies is to determine a species' conservation status. Two widely utilized protocols for status determination are those of the International Union for the Conservation of Nature (IUCN) and NatureServe. This study compares the risk categorization for 58 species of aquatic wildlife extant in North Carolina. The IUCN and NatureServe protocols produced threat rankings that were correlated with each other but very different in terms of how they classified risk. The NatureServe protocol most often placed a species as being in a higher threat...