Augmenting Population Monitoring Programs with Behavioral Indicators During Ecological Restorations

Abstract

Restoration Ecology is the application of principles from Evolutionary Ecology to recover ecosystems that have been degraded, damaged, or destroyed by human activities. Successful restoration requires clearly defined objectives and the means to assess progress in meeting them. Often this includes monitoring population trajectories (changes in population size over time) of focal species. Unfortunately, population trajectories in and of themselves are often ambiguous and open to interpretation. Incorporation of additional information can increase the information content of such monitoring programs. Here we advocate using behavioral indicators, particularly the giving-up density (GUD) of food in experimental foraging patches, to complement more traditional monitoring programs that track changes in population sizes over time. We use the results of two field studies to demonstrate how GUDs reflect changes in environmental quality (background food abundance), changing physiological costs of maintenance over an annual cycle, and risk of predation. We then illustrate, through hypothetical examples, how knowledge of changes in GUDs over time can inform interpretation of actual population trajectories (based on 12 years of monitoring) of four bird species of conservation concern at the United States Forest Service Midewin National Tallgrass Prairie, Illinois, USA. We conclude with a prospectus providing guidelines for incorporating behavioral indicators like the GUD in monitoring programs. Integrating behavioral indicators with more traditional population monitoring approaches provides an effective means of acquiring useful information in a timely and efficient manner.

Keywords:

• ecological restoration
• GUD
• Midewin National Tallgrass Prairie
• population monitoring