From the tree to the continent: diversity and distribution of vascular epiphytes

Abstract

The interaction between species and their environment is shaped by habitat heterogeneity and climatic conditions. While natural factors play a significant role in the dynamics of interactions between species and the surrounding environment, anthropogenic disturbances have the potential to fundamentally alter them. In the context of the Anthropocene, ecologically diverse regions, such as the Neotropics, are considered hotspots of biodiversity but also face substantial threats from human activities. Therefore, understanding how anthropogenic habitat degradation, combined with climatic factors, shapes species distribution is a pressing challenge for the species conservation and preservation of the habitat. While the effects of climate and anthropogenic pressures are relatively well-established for specific groups, drawing comprehensive conclusions remains challenging for diverse yet overlooked groups, such as vascular epiphytes. Thus, this thesis aimed to explore how the distribution of vascular epiphytes is influenced by (a) the effects of degradation in (b) different time periods. Additionally, how the (c) climate influences this distribution at a larger scale. By integrating environmental and anthropogenic aspects, we provide crucial information for the conservation of umbrella species groups, benefiting an even broader range of associated species. In this study, changes in land-cover negatively impacted epiphyte assemblage diversity across all spatial and temporal scales. At the smaller scale, the species richness and composition between forest and degraded areas remained relatively similar. Climatically, epiphytes exhibited higher diversity in more stable areas with increased water availability and mild temperatures. Thus, epiphyte assemblages in preserved landscapes, featuring stable land-cover through the years, low climatic seasonality, ample water availability, and mild temperatures, represent potentially diverse communities deserving targeted preservation efforts. However, areas with conditions distinct from these also have the potential, although limited, to serve as diversity reservoirs.