Species selection for optimizing mine land rehabilitation: Integrating functional traits with the minimum set prioritization technique

Abstract

The selection of promising plant species for mine land rehabilitation is a major ecological challenge, i.e., which species are able to establish desired functions in postmining environments and their availability at reasonable costs. Here, we used the minimum set approach for optimizing the selection of species to achieve specific rehabilitation objectives related to the restitution of trophic interactions and community development during mine land rehabilitation. To that end, we utilized a list of 203 tree species and their functional attributes from Carajás National Forest, Eastern Amazon, Brazil. Many species (111) in the list have been suggested in a previous study as potential candidates for postmining rehabilitation, as they fall within the shared functional space of species successfully established in previous mine land rehabilitation efforts. We defined three rehabilitation objectives related to trophic interactions and community development and combined our species list with the minimum set prioritization framework to select species that achieve rehabilitation objectives at minimum propagation costs, using ease of propagation as a cost surrogate. We found a strong positive correlation between functional diversity within plots and the environmental quality of rehabilitating communities, highlighting its importance for rehabilitation success. Then, we showed that 16 species from the shared functional space can maximize rehabilitation objectives and recommend their use in further rehabilitation/restoration projects. Prioritizing species from the functional attribute list offers advantages over prioritizing species from a raw species list as the former have higher survival rates than species from the undifferentiated species list. That trade-off reinforces the benefits of using the two-step approach suggested here.