Spatial distribution of the common loon (Gavia immer) in New Hampshire.

摘要

The Common Loon (Gavia immer) is located in many portions of North America. By the early 1970's the Common Loon population in New Hampshire had experienced a dramatic decline in historic numbers. In 1975, the Audubon Society of New Hampshire recognized this problem and established the Loon Preservation Committee (LPC). The intent was to collect information regarding the presence or absence of loons and loon productivity, and, educate the public regarding loon ecology and preservation. This dissertation represents the work completed to fulfill the requirements for the Doctor of Philosophy degree in Natural Resources Management at the University of New Hampshire. The research concentrated on analyzing georeferenced loon management data collected by LPC from 1980--2002 and understanding loon habitat occupancy. Specific objectives of this study were to: (1) investigate the colonization patterns of the Common Loon in New Hampshire, (2) identify and prioritize potential loon habitat in New Hampshire, and (3) develop and implement methods to be used by the Loon Preservation Committee for current and future loon management. Methods are described for converting and analyzing a 29-year historical database maintained by the Loon Preservation Committee located in Moultonborough, New Hampshire. Through this effort, techniques and results for: analog to digital data conversion, automating new data collection, and spatial analysis are discussed. Lake perimeter, lake depth, distance to lakes with and without loons, and lake elevation were identified as significant factors for determining loon habitat occupancy in New Hampshire. The results of implementing a GIS-enabled loon habitat occupancy model are presented.