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Antecedentes: La selva alta perennifolia (SAP) se ha transformado por el cambio del uso de suelo. Los cafetales rústicos son parte del paisaje y su abandono puede favorecer la regeneración de la vegetación original. Hipótesis: La protección de cafetales abandonados en SAP, favorece la regeneración natural permitiendo el desarrollo de bosques secundarios en distintas fases de sucesión. Sitio de estudio: Colipa, Veracruz, México. Dos cafetales abandonados y un fragmento de SAP. Métodos: En 24 transectos (50 × 2 m), se registraron y midieron diámetros y alturas de especies leñosas (DAP ≥ 5 cm). En cada transecto se marcaron cuadrantes (2 × 2 m) para registro de especies del estrato arbustivo y plántulas. Se evaluó el estatus de regeneración mediante densidades de plántulas, juveniles y adultos. Resultados: Se registraron 60 especies. El mayor número de especies se presentó en la SAP y el cafetal colindante, fueron los sitios con más especies compartidas. El otro cafetal (alejado 3 km) tuvo la mayor densidad de árboles mientras que la SAP presentó mayor densidad de arbustos y plántulas. El 50 % de las especies características de la SAP en el área se están regenerando en los cafetales, mientras que las especies cultivadas presentaron regeneración pobre o nula. Conclusiones: Después de más de 25 años de abandono, la estructura y composición de especies es similar a la SAP. Los cafetales de sombra abandonados contribuyen a la regeneración natural y funcionan como reservorios de germoplasma nativo para la región.

The behavior of bees is modulated by the presence of other bees and potentially by the visual information transmitted by the different body positions of bees while visiting flowers. We tested whether bee body position promoted the attraction and/or antagonistic behavior of con- and hetero-specific bees that interacted on prickly pear flowers of Opuntia huajuapensis. To test this, we placed dummy model bees of Apis mellifera and the native Lithurgus littoralis in flowers in three common body positions: alert, feeding, and horizontal. The results showed that dummy model bees in feeding and horizontal body positions attracted A. mellifera bees, while the alert position attracted native male L. littoralis. Male L. littoralis bees spent more time attacking model bees in horizontal and alert positions. The position of dummy bees also influenced response times. Bees of A. mellifera responded fastest to L. littoralis in the alert and horizontal position, male L. littoralis responded fastest to con-specific bees in the alert and feeding position, and female L. littoralis responded fastest to A. mellifera bees in the feeding position. A. mellifera reacted fastest to their con-specific bees in the alert and horizontal body positions. Our results demonstrate, for the first time in bees, that the position of individuals on a floral resource provides important visual information that modulates bee behavior, and illuminates aspects that likely have implications for bees in access to floral resources.

As a major disturbance, hurricanes affect growth and phenology of trees. Tree diameters were annually measured for three years, and the phenology of 16 tree species monthly recorded in a seasonally dry tropical forest in Veracruz, Mexico, when on September 2010, Hurricane Karl struck the region. One month later, tree damage was recorded and phenological observations resumed for 12 more months, and diameter measurement for two more years. Tree damage due to the hurricane was high: 10 % were uprooted, 7 % broken and 2 % bent. All trees uprooted died, but some broken or bent trunk trees resprouted (15 % of tagged trees died). Overall, mean diameter growth of trees that survive the hurricane (0.79 cm yr-1) was greater than pre-hurricane growth rate (0.68 cm yr-1). For all the studied species together, leaf fall, leafing, and flowering phenology did not differ between pre- and post-hurricane whereas fruiting was lower for the post-hurricane year. At species level, most species displayed differences in reproductive phenology between pre-hurricane and post-hurricane years. Most species did not flower, lower flowering and fruiting (Calyptranthes schiedeana), or did not fruit (Luehea candida, Maclura tinctoria, Tabebuia chrysantha) the year following the hurricane. In conclusion, due to hurricane damage, tree mortality was high but many trees recovered from damage, and that the hurricane negatively influenced intensity in reproductive phenology, and in turn may alter forest structure, shift species composition, and affect the trophic relationships and functioning of the whole forest community.

Background Tree phenology has been related to abiotic and biotic factors that trigger and regulate phenological patterns. Question We investigated whether tree species classified into ecological groups of species of successional status (late-, early-successional tree species) and seed dispersal mode (anemochory, autochory, zoochory) would display different phenological patterns. Study site and dates A tropical dry forest in eastern Mexico; November 2007 to September 2010. Methods We monthly recorded leaf fall, leafing, flowering, and fruiting in 165 trees belonging to 16 species tagged along a trail inside a forest fragment (21 ha). Monthly precipitation and temperatures data were obtained from the nearest meteorological station. Phenological periodicity was analyzed using circular statistics. Results Leaf fall occurred during the dry season and leafing at the beginning of the rainy season. Flowering at community level was not significantly cyclic because of differences within groups: late-successional and zoochorous species displayed a flowering peak during the rainy season, whereas the early-successional, anemochorous and autochorous species do during the dry season. Fruiting occurred over an extended period but showed a cyclic pattern: Late successional and zoochorous species fruited at the beginning of the dry season, whereas early-successional and autochorous species tend to displayed a peak of fruiting at mid-dry season and the anemochorous at the end of the dry season. Conclusions. Vegetative phenological patterns were similar at the levels studied and were clearly related to climatic variables. However, the phenological patterns of reproduction differed within tree ecological groups and were not consistently correlated with precipitation or temperature.

The soil seed bank has a limited role in the seasonal dry tropical forest regeneration process, but seed removal and germination can also be limiting factors during the early forest recovery. In central Veracruz, Mexico, the soil seed bank was determined en five fallows and two forests. Seed bank decreased from fallow to forest (1303 to 101 seeds m-2); herbs and grasses predominated thus the similarity between species composition of seed bank and vegetation was low. Seed removal and germination were evaluated for Acacia cochliacantha, Caesalpinia cacalaco, Ipomoea wolcottiana and Senna atomaria in contrasting habitats represented by pasture, fallow and forest. Seed removal was determined under treatments of total access, rodent exclosure, and insect exclosure. Caesalpinia (largest seeds) displayed the lowest seed removal (5%), whereas Senna (63%) and Ipomoea (29%) displayed the highest. Rodent exclosure reduced seed removal for Ipomoea (medium-sized seeds); and insect exclosure reduced removal for Senna and Acacia (small seeds). With the exception of Senna (18% germination), the scarified seeds displayed the highest germination percentage (53-99%). For all species, germination was higher in forest than in open habitats, only Senna seeds displayed the lowest germination percentage in the forest habitat. Results suggested that in the dry forest of Veracruz, seed removal may not limit forest regeneration; however seeds must be scarified for use in restoration activities.

Restoring seasonally dry tropical forest is a worldwide priority, since it is the most threatened of all major tropical forest types. In Veracruz, Mexico, the dry forest has been reduced to fragments and fallows representing 7% of the original cover. Our objective was to determine the effect of site condition and seasonality on seedling survival and relative growth rate in height and diameter of selected native tree species. We studied plant performance during two dry and two rainy seasons and the effect of existent woody vegetation > 1 m height. A total of 960 seedlings were transplanted: 40 individuals of six species (Cedrela odorata, Ceiba aesculifolia, Guazuma ulmifolia, Ipomoea wolcottiana, Luehea candida, Tabebuia rosea) in four fallows. Seedling survival and relative growth rate were monitored every four months during two years. Survival was higher in sites with more woody species richness, whereas relative growth rate in height was positively correlated with existent vegetation height. Relative growth rate was higher for all species and sites during the rainy season. In the site with less existent woody vegetation, seedling performance was poor and only Guazuma survived. Overall, Ceiba showed the highest survival rate (82-90%) and the lowest relative growth rate. Guazuma had a high survival (20-94%) and the highest relative growth rate; Cedrela showed the lowest survival (3-7%) and high relative growth rate. Our results suggest that site condition, seasonality, and tree species selection act together on seedling performance during early establishment. A vital implication in terms of ecological restoration is the importance of taking advantage of existent vegetation even if it is scarce.