Ensuring future regeneration success of Qualea grandiflora Mart. (Vochysiaceae) in neotropical savanna (cerrado) biomes by reviewing the available information and identifying research gaps

Abstract

Qualea grandiflora Mart. (Vochysiaceae) is one of the most widespread species within the cerrado formation, which counts amongst the most threatened ecosystems worldwide. Understanding the regeneration ecology of Q. grandiflora is a central requirement for the success of conservation measures and silvicultural management strategies. Exhaustive investigation was carried out into each of the development stages, and the connected processes within the regeneration cycle, to provide a better understanding of the main factors influencing the regeneration ecology and the recruitment dynamics of the species. For this purpose, we analysed 92 different sources of information in this review, divided into two groups (n = 41 with “basic species information” and n = 51 with “specific information about regeneration stages and processes”) relevant for regeneration and silviculture. Our literature review showed the high proportion of studies addressing the processes flowering, pollination and fruiting, whereas the subsequent processes like seed dispersal, seed storage, germination and seedling development are almost entirely lacking. This also applies for spatial information about environmental conditions and the related regeneration processes in Q. grandiflora. This knowledge is important for management, for example, knowledge of the critical distances between flowering and seed producing trees to ensure genetically diverse regeneration and the identification of safe sites for seedling establishment. Most of the practical suggestions in relation to increasing densities or growth of Q. grandiflora seedlings and saplings made in the literature are linked to less intensive fire management strategies adopted at certain times. The use of selective herbivory to reduce the increasing competition pressure exerted by invasive grasses and hampering Q. grandiflora seedlings is also cited. In this study we highlight the need for more complex species-specific information following the development stages and processes of the regeneration cycle so as to prepare a continuous strategy with a range of management approaches.