# Tropical Dry Forest Diversity, Climatic Response, and Resilience in a Changing Climate
## 2 Components of Tropical Dry Forests
### Biodiversity  
Much like the AGB, there are latitudinal trends in the species diversity found across TDFs, although micro-scale differences moderate this effect. Overall, species diversity is lower away from the equator, with plots in Mexico and Brazil typically having 90-100 flora species [39; 77], and equatorial latitudes having much higher diversity. In Costa Rica, plots had over 135 tree species alone and in Panamanian sites, it is estimated that there are over 1000 flora species [12; 13]. Both near the equator and at higher latitudes there are typically more species that are only common to a single plot or successional stage in the TDFs. In Brazil, only 13.5% of species were common across all successional stages, with 43.2% of species unique to only one successional stage [19]. A similar trend occurs in Costa Rican sites, 18% of species found in all forest plots and 48% unique to a single site, with 19% represented by only by a single individual [13].  
Species composition also differs by country. In Brazil, Fabaceae was the most speciose of the families [19; 77]. The family accounted for 25% of the species in the early stage, 41.5% of the intermediate stage, and 21.4% of the late stage. The family with the highest number of individuals, however, was the Anacardiacaceae family, accounting for 50% and 25% of individuals, respectively, for late and intermediate stage sites, respectively [19]. In Costa Rica, however, there was a wider range of abundant species depending on the location and successional stage of the plot. In general, _Quercus oleoides, Rehdera trinervis_, and _Cochlosperum vitifolium_ were abundant in many of the plots [13]. In all Costa Rican plots and successional stages, the most abundant species are dispersed by either wind or by animals [13]. Other studies find that the majority of species in Costa Rican TDF sites have a monoecy breeding system [47]. Of the animals, in Santa Rosa National Park, birds were found to disperse the highest number of individuals and species, followed by other animals, such as bats; however, insects, were the most dominant pollinators in Santa Rosa National Park [47]. Very little is known about pollinators in other parts of the TDFs; however, given the commonalities between Santa Rosa and other TDF sites, it should be expected that other TDFs across the Americas exhibit similar characteristics.  
The factors correlating with species richness also varied depending on site and location. Away from the equator, namely Mexico and Brazil, Bolivia, climatic variables, including precipitation/evapotranspiration, and irradiance have the most significant impact on species diversity and species turnover [78; 79; 80; 81; 82]. There is also an indication that the number of dry months negatively correlates with species diversity and turnover in these latitudes [12]. In the equatorial latitudes, soil and stand age dominate the local and regional scale species variation [13]. Secondary forest sites also indicate that late-stage forests can recover tree and liana diversity comparable to primary mature forests [39].