Beyond Species Richness: Community Similarity as a Measure of Cross-Taxon Congruence for Coarse-Filter Conservation

The use of a surrogate taxon in conservation planning has become questionable because recent evidence suggests that the correlation of species richness between pairs of taxa is highly variable both taxonomically and geographically. Species richness is only one measure of species diversity, however, and recent studies suggest that investigations of cross-taxon congruence should consider a broader range of assessment techniques. The cross-taxon congruence of community similarity between sites among taxa has rarely been examined and may be the most relevant measure of species diversity in the context of coarse-filter conservation strategies. We examined cross-taxon congruence patterns of species richness and community similarity (BrayCurtis similarity) among birds, butterflies, and vascular plants in montane meadow habitats in the Greater Yellowstone Ecosystem. Although patterns of species richness (Spearman rank correlation) varied between taxa, we consistently found a positive correlation in community similarity (Mantel test) between all pair-wise comparisons of the three taxa (e.g., sites with similar bird communities also had similar butterfly communities). We suggest that the success of a surrogate taxon depends on the technique used to assess surrogacy and the specific approach to conservation planning. In the context of coarse-filter conservation, measures of community similarity may be more appropriate than measures of species richness. Furthermore, the cross-taxon congruency of community similarity in our study suggests that coarse-filter conservation may be tenable in montane meadow communities. Más Allá de la Riqueza de Especies: Similitud de Comunidades como una Medida de Congruencia Trans-Taxones para la Conservación de Grano Grueso Resumen: El uso de un taxón sustituto en la planeación de la conservación se ha vuelto cuestionable porque información reciente sugiere que la correlación de riqueza de especies entre pares de taxones es altamente variable taxonómica y geográficamente. Sin embargo, la riqueza de especies es solo una medida de la diversidad de especies, y estudios recientes sugieren que las investigaciones de congruencia trans-taxón debieran considerar una mayor variedad de técnicas de evaluación. La congruencia trans-taxón de la similitud de comunidades entre sitios entre taxones rara vez se ha examinado y puede ser la medida de diversidad de especies más relevante en el contexto de las estrategias de conservación de grano grueso. Examinamos patrones de congruencia trans-taxón de riqueza de especies y similitud de comunidades (similitud BrayCurtis) en aves, mariposas y plantas vasculares en hábitats de praderas montanas en el Ecosistema Greater ††Current address: Department of Biology, Southern Utah University, Cedar City, UT 84720, U.S.A., email jeffrey c [email protected] Paper submitted August 1, 2002; revised manuscript accepted April 24, 2003.