ABSTRACT Aim Environmental filtering shapes the trait and phylogenetic structure of plant assemblages along environmental gradients, though its effects may differ among ecological strategies. To address this, we analyzed the community assembly of epiphytic and lithophytic bromeliads along a coastal–inland gradient, testing predictions of the stress dominance hypothesis (SDH) and phylogenetic niche conservatism (PNC). Location Residual hills of central Rio Grande do Sul, southern Brazil, spanning a vegetation gradient from humid Atlantic Forest to seasonal and savanna‐like woodlands. Methods We surveyed 61 bromeliad species across 71 sites along a 600‐km climatic gradient encompassing variation in temperature, humidity, and solar radiation. For each species, we recorded three categorical traits related to water‐use strategies: rosette form, rosette size, and photosynthetic pathway. We assessed how trait composition, phylogenetic relationships, and environmental factors interact along the gradient using fourth‐corner tests, entropy‐based diversity metrics, phylogenetic RLQ ordination, and the net relatedness index (NRI). Results Trait composition shifted along the gradient, with atmospheric CAM species dominating inland and tank‐forming C 3 species prevailing near the coast. Epiphytes exhibited stronger environmental filtering and greater climatic sensitivity than lithophytes. Environmental filtering promoted convergence of ecological traits under stress but did not produce corresponding phylogenetic structure, providing only partial support for SDH. In contrast, the persistence of tank‐forming C 3 lineages in humid coastal habitats reflected PNC. Conclusions Epiphytes persist through dispersal and recurrent trait convergence under climatic stress, whereas lithophytes reflect long‐term continuity in ancestral niches on rocky outcrops. Ecological filtering and evolutionary constraint operate as distinct yet complementary pathways: SDH drives adaptive trait convergence under stress, while PNC maintains lineage persistence under stability. Together, these processes define the balance between ecological strategy and evolutionary constraint that shapes bromeliad assemblages along the coastal–inland gradient.
Fávero et al. (Sun,) studied this question.