Data from: Carbon assimilation and habitat segregation in resurrection plants: a comparison between desiccation- and non-desiccation-tolerant species of Neotropical Velloziaceae (Pandanales)

Desiccation tolerance is the ability that some organisms show to
equilibrate their water content with that of dry air and recover when
water supplies are re-established. This is a widespread although rare
strategy in angiosperms, and most desiccation-tolerant (DT) species are
restricted to tropical rock outcrops. Such restricted ecological range is
attributed to weak competitive potential caused by low productivity, due
to the temporal limitation in carbon assimilation that occurs when plants
desiccate. However, few studies addressing this question in angiosperms
have been conducted. We investigate 20 species of Velloziaceae of campos
rupestres that differ in their desiccation tolerance. Campos rupestres is
an ecoregion characterized by particular vegetation growing on rocky
substrates that occurs along mountains in central/south-eastern Brazil,
above 900 m a.s.l. It is considered a Neotropical hotspot and the main
centre of diversity for DT vascular plants and the Velloziaceae. Here, we
tested whether carbon assimilation rates, functional traits and species
habitats corroborate the hypothesized trade-off between productivity and
desiccation tolerance. All species showed similar photosynthetic rates
during the wet season; in the dry season, only DT species showed drastic
decrease in their metabolism. Non-desiccation-tolerant (NT) species are
larger than DT ones (i.e. greater maximum plant height; stem volume).
Relative canopy area and stem dry-matter content were lower in DT compared
to NT, while leaf phosphorous concentration was higher in DT. The
remaining morphofunctional traits evaluated did not vary between these
groups. DT species occupied mainly exposed rock soils, while NT species
occurred in deep, sandy soil habitats. Our results support the hypothesis
of a trade-off between desiccation tolerance and productivity in
angiosperms and suggest that DT strategy may only evolve and persist in
habitats where severe growth limitations due to drought limit competition
from more productive species.