Emma Cathleen Steigerwald, Julianne Oshiro, Julia Chen, Vance Vredenburg, Alessandro Catenazzi, Michelle Koo

Many countries have responded to the current global biodiversity crisis by committing to protect 30% of the Earth by 2030, a goal known as “30 x 30”. However, an excessive emphasis on megafauna to the exclusion of other species weakens our current protected area (PA) network. This limited perspective overvalues large, connected PAs, while disregarding the potential impacts of small PAs in preserving biodiversity. Using public databases of 31,828 terrestrial vertebrate species we demonstrate that range sizes for the most vulnerable class of vertebrates, the amphibians, are smaller than those of reptiles, birds, and mammals and suggest that small PAs are overlooked as conservation tools for this group. We found that, though each of many endangered amphibians could have their entire distribution protected by a single microreserve (< 10 km2), the current PA network fails at adequately protecting most threatened amphibian species. Furthermore, we show that many current microreserves have amphibian species richnesses rivaling those of the largest PAs (10,000–100,00 km2), and that PA networks accumulate new amphibian species more rapidly through the addition of smaller rather than larger PAs. Unfortunately, the global rate of new PA establishment has slowed since 2010, so we illustrate global regions where the addition of microreserves could be most beneficial to amphibian conservation. We conclude that incorporating the needs of overlooked taxa into PA design will require us to complement networks of large, connected PAs with many strategically-placed, biodiversity-motivated microreserves.