Tropical dry forests (TDFs) are characterized by pronounced seasonality in precipitation, with several months of prolonged drought, 80% of annual precipitation occurring during a four- to six-month rainy season, and high interannual rainfall variability. Surprisingly, there are relatively few studies addressing patterns of functional trait in tropical dry forest (TDF) ecosystems. Functional trait analysis across plant species and the environment is a rapidly developing research field with many possible applications for forest restoration practice. Trait-based ecological research within TDFs will advance our understanding of how these ecosystems interact with and differ from other tropical ecosystems.
TopIntroduction
Tropical forests share 7% of the total land’s surface of the Earth and harbor a higher diversity at species and ecosystem levels (Hubbell and Foster, 1983; Wilson, 1988; Raven et al.,1993). Tropical forests are characterized by frequent variations in the temperature and precipitation. It is further categorized into moist and dry tropical forests (TDFs). TDFs generally occur under a warm to hot climate and mean annual temperature of >17 ᵒC with >1 evaporation to rainfall ratio, due to frequent drought conditions (of 2-6 months) during the year (Murphy and Lugo, 1986; Olivares and Medina, 1992). TDFs are found in the vast biogeographic region including many countries. However, due to change in climate, some of these highly biodiverse countries (such as Brazil, Egypt, etc.) are under the immense pressure of habitat loss and degradation (Raven et al., 1993). Since TDFs occurs under more arduous and less predictable environment, and are specifically sensitive to dry conditions and increased water stress, which result in increased mortality rate in these forests (Anderegg et al., 2015). It is, therefore, that plant species, with different life history traits such as tree size, successional status (i.e. pioneer and non-pioneer), leaf types (i.e., broad-leaved species and fine-leaved species), N2 fixation ability, and habitat preferences, are predominantly controlled by the prevailing climatic conditions (Chaturvedi et al., 2011).
These highly vulnerable TDFs (Janzen,1988) are in need of development of restoration strategies for their preservation and revival. In practice, it has been observed that each forest area has its own history of disturbance and degree of resilience so that, it is very hard to determine the best strategy to recover that forest ecosystem. Since TDFs are generally characterized by different complex environmental conditions. So, slow and un-predictable vegetation recovery is often observed (Bognounou et al., 2010). Several restoration practices based on old restoration methods, especially by planting native vegetation extended in the past have recorded constrained achievement. Therefore, for a successful restoration of TDFs, the focus should be given on the responses of various species and functional groups (Dhyani and Dhyani, 2016). In previous studies, it has been established that functional ecology has the potential to turn descriptive ecology into more systematic and mechanistic science, thus getting increasing demand among the ecologist. So, for the restoration practices to be successful, it is highly important to adopt an efficient approach in the species selection for restoration planting. Plant functional traits (PFTs) may be one of the best approaches for this.