Protected area systems include sites preserved by various institutions and mechanisms, but the benefits to biodiversity provided by different types of sites are poorly understood. Protected areas established by local communities for various reasons may provide complementary benefits to those established by large-scale agencies and organizations. Local communities are geographically constrained, however, and it remains unclear how effectively they protect biodiversity. We explored this issue by focusing on protected areas established through direct democracy via local ballot initiatives whereby communities vote to tax themselves for open space preservation. We compared the effectiveness of local ballot-protected areas to areas protected by a large-scale conservation actor, The Nature Conservancy (TNC). We evaluated how well the two protected area types correspond with amphibians, reptiles, birds, mammals and special status elements of natural diversity. Local ballot-protected areas differed from those of TNC in terms of size, location, proximity to urban areas and habitat diversity. In terms of potential habitat coverage, local ballot-protected areas outperformed TNC sites for all species groups with the exception of special status elements of natural diversity. While not necessarily targeting wildlife and habitats, we conclude that locally established protected areas can make an important contribution to biodiversity conservation.