How to live in contrasting habitats? Acquisitive and conservative strategies emerge at inter- and intraspecific levels in savanna and forest woody plants

Abstract

Seasonal forests and savannas often occur side by side in Neotropical landscapes, so it is possible to find plant species in both or in just one of these two contrasting habitats. But, what adaptations to the prevailing environmental conditions explain species occurrence in these habitats? In this study, we tested the hypotheses that (i) distinct ecological strategies explain the occurrence of woody species in forests, savannas, or in both habitats, and that (ii) such strategies appear at both inter- and intraspecific levels. We evaluated the habitat preference of 284 woody species using data collected in six paired seasonal forest and savanna habitats throughout the Brazilian Cerrado. To investigate the ecological strategies of forest-specialist, savanna-specialist or generalist species, we used data on functional traits at the inter- and intraspecific levels. We found that acquisitive traits were associated with species occurring in forests, whereas conservative traits were associated with species recorded in savannas. Additionally, our findings indicate that intraspecific variability underlies the ability of species to persist in these contrasting ecosystems. Our results demonstrate how environmental filters select plant species with distinct traits and ecological strategies. Acquisitive traits indicate higher competitive ability and faster resource acquisition for forest species that occur in light-limited environments. On the other hand, conservative traits promote resistance of savanna species to environmental stressors such as fire, drought and low soil fertility. Generalist species matched the strategy of the habitat where they were sampled, which could be explained by high intraspecific trait variability in plant maximum height, leaf thickness, SLA, leaf nitrogen and magnesium contents. Therefore, these are likely to be key traits for adaptation of populations and species in forest and savannas.