The researchers developed a model called Spatially Implicit Neutral Models (SINM) to study diversity in plant species. This model helps understand how different species are distributed in relation to their environment. By using this model, they found patterns in species diversity that cannot be explained by migration or species characteristics alone. The SINM accurately predicts species abundance and can be used to compare rare species with more common ones in different environments. This study focused on tropical forests in Central Africa to demonstrate the effectiveness of the model.