Restoring and conserving rare native ecosystems: A 14-year plantation removal experiment

- Cutting non-native pine plantations restored native savannas and prairies.
- Native species richness was 34-50% higher on cut plots.
- Cut plots had 10 state-listed rare plant species; uncut control plots had none.
- Only cut plots contained oak trees, key to restoring oak savannas
- Floral resources for invertebrates were greatest on cut plots.

Forest plantations occupy 2% of Earth's land surface and are increasingly important in biological conservation both through their establishment and removal. To restore conservation-priority oak savannas and prairies in the Midwestern United States, we began a conifer plantation removal experiment in northwestern Ohio in 2002 and measured plant community response, including nectar plants for conservation-priority invertebrates, during a 14-year period. Oak (Quercus) trees, crucial to restoring savanna structure, only became established on plots where conifers were cut. In the understory, native species richness/0.05 ha was 34-50% higher on plots where conifers were cut than on control plots in uncut plantations. By year 14, cut plots accrued 13 species with high coefficients of conservatism (specialist species typifying high-quality natural habitats) and 10 state-listed rare species; uncut plantations did not contain any such species. With 71 wetland species detected during the experiment (out of 370 total plant species), only cut plots developed a wetland-upland biophysical gradient diagnostic of diverse Midwestern savanna-prairie landscapes. Between year 1 and 14 after plantation cutting, cover of nectar plants utilized by federally endangered Karner blue butterflies (Lycaeides melissa samuelis) doubled, while cover of these plants remained negligible in uncut plantations. Similarly, cover of plants utilized by bees increased by 24 × after plantation cutting. Cutting plantations rapidly and persistently benefited native species for at least 14 years, with minimal increase in non-native plants.