Despite its high diversity and being one of the most desired habitats for human settlements and exploitation, Tropical Dry Forest (TDF) is among the most threatened ecosystems of the world and little information exists about its natural regeneration. Although our limited knowledge of TDF succession includes several descriptions of the process in terms of species composition, diversity and vegetation structure, the functional domain remains largely unexplored. Consequently in this study we aim to: 1) introduce a functional perspective in the description of the TDF successional process, 2) depict the correspondent successional mechanisms; 3) characterize functional groups and 4) explore the potential use of our results for the spectral detection of the different successional stages. For this purpose, we evaluated the successional change of nine functional traits related to water use, light acquisition, nutrient conservation and CO2 acquisition in 25 of the most abundant tree species occurring in a chronosequence of nine plots representing the local mosaic of forests and three different successional stages: early, intermediate and late.
Results/Conclusions
The different trends of the functional traits along succession, as well as the correlations among them, suggest plant strategies focused on heat dissipation and water conservation for the early successional stages. In fact, provided that early and intermediate stages are not significantly different in functional terms, the recovering of functionality occurs after the recovering in species composition and vegetation structure. Functional separation between the species evaluated is better depicted by two functional groups than by the successional stages. One functional group mostly represents to the early and intermediate stages and to pioneer species whereas the other mostly represents to the late stage and to late successional species. Functional grouping is not explained by phylogenetic correlations. Functional traits such as net photosynthesis, water use efficiency and specific leaf area can be used with an acceptable accuracy to discriminate between functional groups and early vs late stages. However, the incorporation of other traits (i.e. structural) could help in the differentiation of a greater number of successional stages specially by using remote sensing technologies. Concluding, the functional assessment of TDF succession results fundamental to properly understand the natural regeneration of the system as well as to develop strategies for its study and conservation.
