Conservation of genetic diversity, one of the three main forms of biodiversity, is a fundamental concern in conservation biology as it provides the raw material for evolutionary change and thus the potential to adapt to changing environments. By means of meta-analyses, we tested the generality of the hypotheses that habitat fragmentation affects genetic diversity of plant populations and that certain life history and ecological traits of plants can determine differential susceptibility to genetic erosion in fragmented habitats. Additionally, we assessed whether certain methodological approaches used by authors influence the ability to detect fragmentation effects on plant genetic diversity. We found overall large and negative effects of fragmentation on genetic diversity and outcrossing rates but no effects on inbreeding coefficients. Significant increases in inbreeding coefficient in fragmented habitats were only observed in studies analyzing progenies. The mating system and the rarity status of plants explained the highest proportion of variation in the effect sizes among species. The age of the fragment was also decisive in explaining variability among effect sizes: the larger the number of generations elapsed in fragmentation conditions, the larger the negative magnitude of effect sizes on heterozygosity. Our results also suggest that fragmentation is shifting mating patterns towards increased selfing. We conclude that current conservation efforts in fragmented habitats should be focused on common or recently rare species and mainly outcrossing species and outline important issues that need to be addressed in future research on this area.

We compared phenological patterns of tree species of the family Bombacaceae in three seasonal forests in Mexico and Costa Rica whose dry seasons vary in duration and intensity. The objectives were to (1) determine intraspecific variation in phenology between sites in different geographic locations with different precipitation regimes, (2) compare interspecific phenological patterns within sites during one year, and (3) document seasonal pollinator use of floral resources at one site in relation to the flowering phenology of these species. To determine the sequence of phenological events in trees of the family Bombacaceae across three study sites, phenology of marked individuals was recorded every 2 wk from September 2000 through August 2001 for six species. To estimate the importance of bombacaceous species in the diet of nectarivorous bats, pollen samples were collected from the bodies or feces of bats once every 2 wk during flowering. Our study suggests that phenological patterns of the Bombacaceae family in Neotropical dry forests are mainly constrained by phylogenetic membership and adaptive selective pressures associated with competition for pollinators. Abiotic factors related to precipitation and soil water content appear to be regulating leaf flushing and abscission, but the principal causes of flowering are related to ultimate factors associated with competition for pollinators. This study is the first that evaluates the phenological pattern of species and genera of the same family at different latitudes in a similar life zone.

Forest fragmentation and the resulting spatial isolation of tree species can modify the activity of pollinators and may have important implications for the reproductive success and mating systems of the plants they pollinate. The objectives of this study were to (1) evaluate the effect of forest fragmentation on pollinator activity in bat‐pollinated bombacaceous trees and (2) determine the effects of forest fragmentation on reproductive success and mating systems of bombacaceous trees. We studied these parameters in three bombacaceous tree species in tropical seasonal forest of Chamela, Jalisco, Mexico, and Osa and Guanacaste, Costa Rica. For Ceiba aesculifolia, more visits were observed in fragments by both Glossophaga soricina and Leptonycteris curasoae. For Ceiba grandiflora, Musonycteris harrisoni visited flowers exclusively in forest and G. soricina visited more flowers in forest than in fragments; no difference was shown by L. curasoae. For Ceiba pentandra in Chamela, no differences were found in visitation by G. soricina between forest and fragments; L. curasoae visited significantly more flowers in forest. Ceiba pentandra received more visits by Phyllostomus discolor than G. soricina in Guanacaste, whereas no bat visitors were observed in Osa. Total mean flower production was greater in fragments than forest for C. aesculifolia, whereas no difference was observed for C. grandiflora. Fruit set was greater in forest than in fragments for C. grandiflora, whereas no difference was observed for C. aesculifolia. Outcrossing rates were high for C. aesculifolia and C. grandiflora in Chamela, and for C. pentandra in Guanacaste, independent of tree habitat, while C. pentandra in Osa showed a mixed‐mating system. The effects of forest fragmentation on bat pollinators, plant reproductive success, and mating patterns varied depending upon the bombacaceous species. This variability was associated with the effects that forest fragmentation may have on differences in flowering patterns, bat foraging behavior, and plant self‐incompatibility systems. RESUMEN La fragmentatión de bosques y el aislamiento espacial, producto de este fenómeno, pueden modificar la actividad de los polinizadores y pueden tener implicaciones importantes sobre el éxito reproductivo y los sistemas de apareamiento de las plantas que polinizan. Los objetivos de este estudio consisten en: (1) evaluar los efectos de la fragmentatión de bosque sobre la actividad de los polinizadores de árboles de Bombacaceas, y (2) determinar los efectos de la fragmentación sobre el éxito reproductivo y el sistema de apareamiento de árboles de Bombacaceas. Evaluamos estos parámetros en 3 especies de árboles de esta familia en bosques estacionales en Jalisco, México y Guanacaste y Osa, Costa Rica. Las flores de Ceiba aesculifolia fueron mas visitadas en fragmentos por Glossophaga soricina y Leptonycteris curasoae. En Ceiba grandiflora, Musonycteris harrisoni visitó flores exclusivamente en el bosque y G. soricina visitó mas flores en el bosque que en los fragment...