Consequences of Habitat Fragmentation on the Reproductive Success of two Tillandsia species with Contrasting Life History Strategies

Abstract

Fragmentation of natural habitats generally has negative effects on the reproductive success of many plant species; however, little is known about epiphytic plants. We assessed the impact of forest fragmentation on plant–pollinator interactions and female reproductive success in two epiphytic Tillandsia species with contrasting life history strategies (polycarpic and monocarpic) in Chamela, Jalisco, Mexico, over three consecutive years. Hummingbirds were the major pollinators of both species and pollinator visitation rates were similar between habitat conditions. In contrast, the composition and frequency of floral visitors significantly varied between habitat conditions in polycarpic and self-incompatible T. intermedia but not in monocarpic self-compatible T. makoyana. There were no differences between continuous and fragmented habitats in fruit set in either species, but T. makoyana had a lower seed set in fragmented than in continuous forests. In contrast, T. intermedia had similar seed set in both forest conditions. These results indicate that pollinators were effective under both fragmented and continuous habitats, possibly because the major pollinators are hummingbird species capable of moving across open spaces and human-modified habitats. However, the lower seed set of T. makoyana under fragmented conditions suggests that the amount and quality of pollen deposited onto stigmas may differ between habitat conditions. Alternatively, changes in resource availability may also cause reductions in seed production in fragmented habitats. This study adds to the limited information on the effects of habitat fragmentation on the reproductive success of epiphytic plants, showing that even related congeneric species may exhibit different responses to human disturbance. Plant reproductive systems, along with changes in pollinator communities associated with habitat fragmentation, may have yet undocumented consequences on gene flow, levels of inbreeding and progeny quality of dry forest tillandsias.

Self-Compatibility and Reproductive Success of Oenothera drummondii subsp. drummondii: Is It Similar between Native and Non-Native Populations?

“…Reproductive success in plants usually is measured by seed set (e.g., [52]), number and weight of fruits (e.g., [53]), fruit set, seed set, seed development [54,55]) or germination [56]. However, the most commonly used parameters are fruit set, seed set and germination, since these represent the final product of one reproductive stage process (pollination, fertilization, or seedling emergence).…”

Genetic Diversity and Population Structure of Rhododendron rex Subsp. rex Inferred from Microsatellite Markers and Chloroplast DNA Sequences

“…Firstly, habitat destruction and loss can cause a decline in the distribution range and population and limit the natural regeneration of a species. Secondly, habitat destruction and loss can increase selfing rates and decrease pollen diversity, thereby affecting a species's reproductive success [23,25]. Finally, habitat destruction and loss increase genetic drift and inbreeding and reduce gene flow in the fragmented populations of species and substantially decrease species genetic diversity and adaptation to the changing environment.…”

Extraction and Identification of Volatile Organic Compounds in Scentless Flowers of 14 Tillandsia Species Using HS-SPME/GC-MS

“…One of the functions of the emission of VOCs from a flower’s plant is the attraction of pollinators. Pollinators like hummingbirds, bats, moths, and bees are known in the Tillandsia genus [ 35 , 36 , 37 ]. Their attraction is most of the time very specific [ 11 ].…”

“…It is the second species after T. paleacea with a high number of identified monoterpenes. Finally, it is the only species with the phenylpropanoids/benzenoids methyl ortho-anisate (35) and phenylethyl acetate (29).…”