Biodiversity distributions can be quantified as alpha (taxonomic richness), and beta (compositional heterogeneity) components. In both cases, accurate and detailed assessments require substantial resources, so surrogate measures have been proposed and tested. Scientists from the New York Natural Heritage Program (NHP), working in over 140 New York State Parks, recorded occurrences of 128 different ecological communities, 98 significant (rare or exemplary) ecological communities, and 312 rare species. I used their data to test whether community distributions were valid surrogates for rare species diversity at alpha and beta levels. I found that (1) alpha patterns among the State Parks were similar for NHP significant communities and rare species; (2) beta patterns were contrasting, such that NHP significant communities were weak surrogates at this level; (3) alpha distributions were poor predictors of Beta distributions among parks; and (4) a large fraction of beta diversity is attributable to variation in geographic region, but most State Parks and all State Park Regions make unique contributions.