Alaska to Ecuador mega-experiment shows seeds are more likely to be munched toward the tropics and lowlands, as Darwin predicted.

The biotic province of the Sierra Madre del Sur presents a mosaic of woodlands at different successional stages due to frequent modifications in land use. In this study, we analyzed changes in woody flora across three successional stages of pine-oak forest: early, intermediate, and mature. Vegetation composition and diversity were characterized in 10 plots (each 0.28 ha). The mature stage had the highest values for species richness, abundance, and diversity. Pioneer plants were dominant in the early-successional site and may promote the establishment of late-successional species. The vegetation structure was more complex in the mature stage, where members of the Quercus genus were co-dominant with Pinus species. Pine tree richness was highest in the early-successional stage, and its abundance increased at the intermediate-successional site. These results suggest that Pinus species can grow in perturbed and sunny environments but also require favorable edaphic and microclimatic conditions, such as those found in intermediate woodlands. Results of this fieldwork support the initial floristic composition succession model, which suggests that species present at early stages will also occur in subsequent stages. Ecological succession may be considered to be a natural restoration process, and thus, conservation strategies should focus on maintaining distinct successional communities in addition to mature forests in order to preserve a high number of species.

Tropical dry forests (TDFs) are affected by land-use changes. These modifications impact their composition and arboreal structure, as well as the availability of food for several bird groups. In this study, we evaluated the foraging preferences in zoochorous trees of fruit-eating birds during the dry season of the year in three successional stages (early, intermediate, and mature) of TDFs in southern Mexico. The fruits of these trees are important in the diet of several birds during the dry season, a period during which food resources are significantly reduced in TDFs. We estimated foliar cover (FC) and foliage height diversity (FHD) of zoochorous trees in 123 circular plots. These variables were recognized as proxies of food availability and tree productivity. Foraging preferences were evaluated at the community level, by frugivore type, and by bird species. We evaluated the effect of the structural variables and the fruit size of zoochorous plants on fruit removal by birds and related the bird body mass and fruit size removed in the successional gradient. A total of 14 zoochorous tree species and 23 fruit-eating bird species were recorded along the successional gradient. Intermediate and mature stages showed greater fruit removal. The birds removed mainly B. longipes fruits across the three successional stages. The FHD and fruit size were important drivers in the selection of zoochorous trees and fruit removal by fruit-eating birds. Fruit size and bird body mass were positively related along the successional gradient. The results suggest that fruit removal by fruit-eating birds in the successional gradient can promote the demographic dynamics of several zoochorous tree species, especially of Bursera spp. along the TDFs.

Mexico is the leading exporter of mangos worldwide, and ‘Ataulfo’ is one of the most popular cultivars. However, their production has dramatically dropped in recent years due to the high incidence of nubbins. One of the possible causes is the presence of a delayed self-incompatibility found in this cultivar; thus, proximity to compatible cultivars may help to reduce this incidence. Nevertheless, there is a lack of studies that have rigorously tested this hypothesis in this cultivar. For two consecutive years, the present study evaluated the incidence of nubbins, as well as the quality and quantity of commercial fruits of ‘Ataulfo’ trees located at 10, 30, and 50 m away from ‘Haden’ cultivar. Additionally, the yield and economic income of different planting designs were estimated. During both sampling periods, our results clearly indicated that at 10 m away from ‘Haden’ individuals, ‘Ataulfo’ trees presented a lower incidence of nubbins and higher production of commercial fruits, and higher yield and total income per hectare than at 30 or 50 m away from them. These results indicate that planting designs of ‘Ataulfo’ trees located 10 m away from ‘Haden’ will help to satisfy the increasing demand for mangos of this cultivar in the international market.