Effects of Forest Fragmentation on Pollinator Activity and Consequences for Plant Reproductive Success and Mating Patterns in Bat‐pollinated Bombacaceous Trees¹

Abstract

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...

Remnant Pachira quinata pasture trees have greater opportunities to self and suffer reduced reproductive success due to inbreeding depression

“…There is, however, significant variation in the Malvaceae, with a number of species exhibiting mixed mating systems . Notably the genus Ceiba has shown outcrossing and mixed mating varying both within and among species (Quesada et al, 2004). Controlled pollinations in this study showed a varied ability to self among P. quinata trees, with 50% of trees failing to self, whereas 12.5% showed high seed set under selfing.…”

Mating system and early viability resistance to habitat fragmentation in a bird-pollinated eucalypt

“…Indeed, as far as we are aware, there are currently only five published studies of open-pollinated Neotropical trees that have associated changes in mating patterns of individual trees caused by habitat disturbance with proxies of fitness (Rocha and Aguilar, 2001;Cascante et al, 2002;Fuchs et al, 2003;Quesada et al, 2004;Breed et al, 2012), and a single study conducted from Japan (Hirayama et al, 2007). As expected, selfing (4 of 6 studies), biparental inbreeding (2 of 3 studies) and correlated paternity (3 of 4 studies) tended to be negatively associated with fitness.…”

Temporal variation in pollen dispersal and breeding structure in a bee-pollinated Neotropical tree

“…Isolated populations may receive fewer flower visitors because of the decline in the richness and abundance of pollinators, modifications in species composition and limitation in movement among patches (Cascante et al, 2002;Goverde et al, 2002;Quesada et al, 2004). However, an increased number of studies has been showing that long-distance pollen flow is common in Neotropical trees (Hamrick and Murawski, 1990;Nason et al, 1998; Latouche-Hallé et al, 2004; Dunphy and Hamrick, 2007) and also that gene flow may occur between forest fragments and isolated remnant trees (White et al, 2002, Dick et al, 2003.…”