Avoiding the dry season: dispersal time and syndrome mediate seed dormancy in Neotropical savanna grasses

Date: 25, May, 2018
Author(s):   Desirée M. Ramos, Pedro Diniz, Mark K.J. Ooi, Fabian Borghetti, José F.M. Valls
Publisher: Journal of Vegetation Science

In seasonal rainfall systems, seed dormancy is a strategy to avoid germination and seedling emergence in the dry season. Grass species in Brazilian savannas (Cerrado) show variation in seed dispersal timing and mechanisms, and occur in different habitat types (distinguished by soil moisture) within a seasonal rainfall environment. However, it is unknown whether dormancy has evolved in these systems as a dominant way in which germination is deferred, or how it correlates with other key traits such as dispersal, where known trade‚Äźoffs exist for avoiding competition. We asked whether seed germination and dormancy vary with dispersal and abiotic factors in savanna systems. Specifically, we assessed dormancy by comparing seeds: (1) from species living in habitats with contrasting soil moisture during the dry season (open savannas vs wet grasslands); (2) dispersed at different times (early in the wet season, late in the wet season and in the dry season); and (3) showing alternate dispersal syndromes (barochoric vs anemochoric).