INTRODUCTION

The emphasis of this volume is on quantitative approaches to conservation. This calls for the consideration of key issues related to study design, statistical analyses, and interpretation of quantitative results. In Chapter 1, we argued that conservation targets should be developed from sound empirical data. Chapter 2 reviewed some of the approaches that have been used to establish numerical targets. In this chapter, I examine challenges posed by conservation target setting from a quantitative perspective. Although setting targets is crucial to achieve conservation goals, this does not mean that it is an easy proposition!

Among the challenges associated with conservation target setting, I will focus on the following:

1. Determining appropriate benchmarks for conservation target development. Setting targets implies that ecological conditions of reference have been agreed upon by the members of a research team.

2. Selecting the level(s) of organization for which we will develop targets. Should targets be set for species/populations? Species assemblages? Ecosystems/habitat patches/landscape units? Ecological processes? Ecological stressors?

3. Choosing appropriate units to express targets. For example, a land manager might prefer to express targets in terms of timber volume that can be harvested annually, whereas ecologists might focus on the area and configuration of habitat that should be present at all times over the landscape to maintain viable populations of focal species. Each unit has advantages and disadvantages. Ideally, a statistical relation can be established between them to meet multiple needs simultaneously.

4. Selecting the most appropriate study design to guide the development of conservation targets. What are the options and tradeoffs in study design associated with the investigation of species/species assemblage/ ecosystem response to ecological gradients in space and time?