SPATIAL FIDELITY OF PLANT, VERTEBRATE, AND INVERTEBRATE ASSEMBLAGES IN MULTIPLE-USE FOREST IN EASTERN AUSTRALIA

The design of a protected areas network that contains or represents as many species as possible (maximum complementarity of areas) is a firs t step toward in situ conservation of species biodiversity. In the abs ence of complete species inventories, however, area selection must emp loy surrogate data such as the distribution of plant or vertebrate spe cies. The degree to which the use of these taxa results in a network o f sites with maximum complementarity for others depends on levels of a ssemblage fidelity among taxa. Assemblage fidelity is defined here as the degree to which assemblages from different phylogenic groups co-oc cur in space and time. We examined the spatial fidelity of ground-acti ve invertebrate (ants and several beetle families: Carabidae, Scarabae idae, Pselaphidae), vascular plant, and vertebrate assemblages (birds, small mammals, frogs, and reptiles) at 56 sites in a range of eastern Australian forest types. We used unlogged (n = 32) and logged (n = 24 ) forest sites. Assemblage fidelity was assessed by ordination and Man tel correlation, and patterns of species richness and species turnover that helped explain the findings were analyzed by simple correlation, cluster analysis, and two indices of beta diversity. Our analyses rev ealed general assemblage fidelity among plant, vertebrate, and inverte brate assemblages, and results were consistent in both unlogged and lo gged forest. In several forest types, however, fidelity among inverteb rates and plants was low due to high invertebrate turnover. Overall le vels of species turnover were much higher for vascular plants and inve rtebrates than for vertebrates. Species richness patterns at individua l sites were generally uncorrelated among taxa. Our findings suggest t hat (1) the exclusion of invertebrates from biodiversity surveys canno t be justified on the assumption that plant and vertebrate assemblages act as surrogates for invertebrate species-level biodiversity or on t he basis of cost-efficiency; (2) both spatial fidelity and species tur nover are useful for evaluating the role of selected taxa as surrogate s for the species-level biodiversity of others; (3) the selection of s ites for in situ biodiversity conservation should consider taxa that e xhibit high levels of species turnover; and (4) the inclusion of inver tebrates in biodiversity surveys may offer considerable cost savings a nd be more representative of species biodiversity than conventional pl ant and vertebrate surveys.