ELSEVIER PII: S0006-3207(97)000 I 7-7 Biological Conservation Vol. 83, No. 1, pp, 69-76, 1998 © 1997 Elsevier Science Ltd All rights reserved. Printed in Great Britain 0006-3207/98 $19.00 + 0.00 A TEST FOR THE ADEQUACY OF BIOINDICATOR TAXA: ARE TIGER BEETLES (COLEOPTERA: CICINDELIDAE) APPROPRIATE INDICATORS FOR MONITORING THE DEGRADATION OF TROPICAL FORESTS IN VENEZUELA? Jon Paul Rodriguez,"* David L. Pearson b & Roberto Barrera R. a "Instituto de Zoologia Tropical, Universidad Central de Venezuela, Apdo. 47058, Caracas 1041-A, Venezuela hDepartment of Biology, Arizona State University, Tempe, AZ 85287-1501, USA (Received for publication 12 March 1997) Abstract Indicator species can be a valuable tool for conservation research. Their use has been divided in two categories." inventory studies and monitoring studies. Tiger beetles (Coleoptera: Cicindelidae) have been identified as appropriate indicators for inventory studies. Here we test their value as potential bioindicators for monitoring habi- tat degradation in Venezuela. We analyze the general habitat associations of 47 of the 51 species of this insect family known to occur in Venezuela. We also analyze the assemblage patterns of forest-floor dwelling species asso- ciated with contiguous forest patches of primary and sec- ondary forest in two sites. At the family level, tiger beetles occupy most of the major habitat types of Venezuela, but individual species tend to be restricted to one or two habitats. Forest-floor species assemblages change signifi- cantly with the degree of forest disturbance, and each stage of disturbance is characterized by a particular sub- set of species. Species associated with intermediate levels of" disturbance show larger habitat breadth than those located at the extremes of the spectrum. The results of this study provide evidence that supports the use of tiger beetles as bioindicators for monitoring the degradation and regeneration of tropical forests. © 1997 Elsevier Science Ltd Keywords: Bioindicators, Cicindelidae, Coleoptera, habitat quality, tiger beetles, tropical forests, Venezuela. INTRODUCTION The potential use of indicator species for conservation research can be divided in two basic categories (Kremen et al., 1993; Pearson, 1994). First, monitoring studies *To whom correspondence should be addressed at present address: Ecology and Evolutionary Biology Department, Princeton University, Princeton, NJ 08544-1003, USA. 69 evaluate changes in habitats or ecosystems over time, such as successional stage or habitat degeneration. In this context, the choice of an indicator will be served best by a taxon that is sensitive to environmental change. On the other hand, inventory studies record dis- tributional patterns of taxa or ecological units over geographical space, often with the purpose of identify- ing areas for establishing nature reserves. Here, the choice of indicators should favor taxa whose distribu- tion or abundance correlate, for example, with areas of high endemism or high species diversity (Erwin, 1991). However, the vast majority of studies that rely on bioindicators have used taxa with little or no initial assessment of their adequacy as indicators. Many of these studies have focused on taxa that are either of high public concern (such as endangered species) or have been coincidentally the object of previous studies by the scientists intending to use indicators (Pearson, 1994). For this reason, a series of criteria has been proposed for the objective selection of an indicator taxon (Noss, 1990; Pearson & Cassola, 1992; Pearson, 1994). These criteria are: 1. taxonomically well known and stable, so that populations can be readily defined; 2. biology and natural history well understood -- limiting resources, enemies, physical tolerances, and all stages of the life cycle available to readily incorporate into hypotheses and experimental design; 3. populations readily surveyed and manipulated such that tests are logistically simple and inexper- ienced students and non-professionals can be trained easily to help conduct studies; 4. at higher taxonomic levels (order, family, tribe, genus), occurrence over a broad geographic range and breadth of habitat types, so that results will be broadly applicable;