Similar won’t make it: Coexistence, habitat availability and suboptimal restoration

In the context of the looming biodiversity crisis, adding patches of habitat has been proposed as a restoration strategy in several ecosystems. However, these interventions rarely mimic the conditions of the natural habitats precisely. Consequently, not all species equally benefit from the restored habitat, fostering a difference in species fitness that could generate an imbalance in the equalizing and stabilizing mechanisms that enable species coexistence, leading to competitive exclusion. Using a metapopulation model, we explore how the introduction of habitat patches with biased fitness advantages affects species coexistence. We show that while adding habitat patches generally increases species occupancy, suboptimal patches can favor one species, disrupting the stabilizing and equalizing mechanisms that enable coexistence, leading to competitive exclusion. This impact on the coexistence regime is particularly pronounced in species with high niche overlap and high colonization-extinction ratios. Our results highlight the double-edged sword effect of suboptimal restoration, revealing potential unintended consequences that could exacerbate biodiversity loss. On the other hand, restoration favoring endangered species is also identified as a conservation tool. The present study advances in the mechanistic comprehension of habitat restoration, a necessary endeavor in the face of the challenges posed by global change.