LAUSR

For many species, facilitation can result in transient species coexistence, but subsequent competition can limit long-term coexistence. Adaptive phenotypic variation in response to increased competition following facilitation, however, could be a means of prolonging coexistence, although this hypothesis remains largely unexplored. Resprouting shrubs following fire in Mediterranean heathlands facilitate seedling establishment and growth of subshrub species such as the carnivorous plant Drosophyllum lusitanicum. Nevertheless, shrub canopies interfere with prey capture by established D. lusitanicum plants, potentially reducing fitness with increasing time since fire. At three heathland sites in southwestern Spain, we examined the relationship between stem morphology and shrub canopy cover to determine whether D. lusitanicum exhibited vertical or horizontal elongation to avoid shade or interference with prey capture. We also quantified individual performance responses (e.g., survival, growth, flower production) as a function of stem morphology and size of D. lusitanicum plants and shrub canopy cover. Adult plants of D. lusitanicum showed greater vertical elongation with increasing shrub canopy cover. Small adult plants showed an increased likelihood of flowering with increasing shrub canopy cover. The number of flowers produced by flowering plants decreased with vertical elongation when shrub cover was low. We illustrate how coexistence of foundational shrubs and D. lusitanicum could be maintained by a combination of facilitation of D. lusitanicum seedlings and small adults by shrubs and adaptive changes in stem morphology in established individuals to avoid shrub interference, allowing the replenishment of a fire-regulated, persistent seed bank.