Monodominance in a forest of Brosimum rubescens Taub. (Moraceae): Structure and dynamics of natural regeneration

摘要

The study was conducted in a Brosimum rubescens Taub. monodominant forest in Nova Xavantina, Mato Grosso state (14°49.8'S and 52°9.6'W), in the transition zone between the Cerrado and Amazonian Forest in central Brazil. The structure and dynamics of the natural regeneration was compared over a five-year period to identify patterns that affect seedling establishment and explain the maintenance of B. rubescens dominance. We raised the following questions: how does the structure and dynamics of a monodominant forest regeneration vary over time? What patterns affect seedling establishment and help to explain the maintenance of the monodominance of B. rubescens? Natural regeneration was sampled in 30 plots of 1 m × 1 m (seedlings), 2 × 2 (saplings), 5 × 5 (poles) and 10 × 10 (treelets). In the first inventory, the natural regeneration structure was characterized by a higher concentration of individuals in lower height classes and the largest number of seedlings of B. rubescens may be related to rainfall distribution in previous years. Seedling establishment may be limited by drier periods such as " El Ni?o" events, or by specific light conditions reaching the forest floor. Formation of a persistent seedling bank may provide a competitive advantage for the regeneration of B. rubescens in conditions of gaps pre-opening thus contributing to monodominance maintenance.