Reproductive success of Cabralea canjerana (Meliaceae) in Atlantic forest fragments, Brazil

Abstract

Abstract:In Brazil, the Atlantic forest remnants have high biological diversity and a high level of endemism, but very little is known about the reproductive success of native species. Cabralea canjerana is a common tree in the Montane Atlantic forest, and its reproduction is highly dependent on pollinators. In order to contribute with the particular knowledge on this species, we collected data in three fragmented and three continuous forest sites, where the effects of fragmentation on both mutualistic (pollination) and antagonistic (seed predation) interactions were analysed. We determined fruit production and weight of 25 trees per site. The number of seeds and the percentage of predated and aborted seeds were also accessed for seven fruits of 10 trees per site. Pollinator visitation frequencies to flowers were recorded in two forest fragments and in two sites of the continuous forest. Our data showed that plants of C. canjerana produced more fruits (z-value=-8.24; p<0.0001) and seeds per fruit (z-value=-6.58; p=0.002) in the continuous than in the fragmented sites. This was likely due to differences in pollination, because the number of pollinator visits was higher in the continuous forest than in the fragments. Seed abortion (z-value=4.08, p<0.001) and predation (z-value=3.72, p=0.0002), on the other hand, were higher in the fragmented than in the continuous sites. Then, mutualistic and antagonistic interactions were affected by fragmentation, decreasing the reproductive success of the study tree. This study was the first to show a decrease in the reproductive output in forest fragments in an Atlantic forest tree species. This decrease may threaten the population structure and viability of C. canjerana in forest fragments. Rev. Biol. Trop. 63 (2): 515-524. Epub 2015 June 01.Key words: Cabralea canjerana, fruit production, habitat fragmentation, plant-pollinator interaction, moth pollination, reproductive success, pre-dispersal seed predation, seed set.Habitat fragmentation may disrupt plantpollinator interactions by changing the abundance and/or the identity of floral visitors (Lovejoy, 1980;Roubik, 1993;Aizen, & Feinsinger, 1994a;Aizen, & Feinsinger, 1994b;Matheson, Buchamann, O'Toole, Westrich, & Williams, 1996;Murcia, 1996;Prach, Pysek, & Smilauer, 1997). Because floral visitors can differ in their ability to transfer pollen, changes in the pollinator assemblages following fragmentation may affect plant reproductive success (Aizen, & Feinsinger, 1994b). Studies conducted during the past few decades show that fragmentation may affect the reproduction of various plant species in different ways. Most of these studies show decreases in the richness and abundance of pollinators and in the number of pollinator visits in response to fragmentation, leading to a decrease in the reproductive output of plants (Aizen, & Feinsinger, 1994a;Kolb, 2008). In contrast, other studies found no changes in the reproductive output of plants in fragmented habitats (e.g., Aldrich & Hamrick, 1998;Dick, 2001;Lopes, & Buzato, 2007;...

The influence of El Niño and edge effects on the reproductive phenology and floral visitors of Eschweilera tetrapetala Mori (Lecythidaceae), an endemic species of the Atlantic Forest of northeastern Brazil

“…Decreases in successful reproduction in fragmented forest environments have been associated with decreases in the qualities and quantities of pollinators found there (Aguillar & Galleto 2004). Similar results were observed with Cabralea canjerana (Meliaceae), which was visited by fewer pollinators, and demonstrated limited reproductive success in forest fragments when compared to continuous areas of Atlantic Forest (Franceschinelli et al 2015).…”

“…Numerous studies have demonstrated that edge effects reduce the availability of abiotic resources such as water and soil nutrients (Dunley et al 2009;Athayde & Morellato 2014;Aizen & Feinsinger 1994;Franceschinelli et al 2015), and diminish fruit set as compared to that seen in the forest interior (Dunley et al 2009;Athayde & Morellato 2014).…”

“…Disturbances of plant-pollinator interactions can also result from habitat fragmentation, and edge eff ects can further alter pollinator frequencies and abundances -and therefore pollination services -which can lead to drastic eff ects on both pollinator and plant populations (Aizen & Feinsinger 1994;Franceschinelli et al 2015). While analyzing edge effects on the pollination and reproduction of Meliaceae species in the Atlantic Forest of southeastern Brazil, Franceschinelli et al (2015) observed that the numbers of pollinators of the arboreal species examined were greater in the forest interior than at the forest edge.…”

“…While analyzing edge effects on the pollination and reproduction of Meliaceae species in the Atlantic Forest of southeastern Brazil, Franceschinelli et al (2015) observed that the numbers of pollinators of the arboreal species examined were greater in the forest interior than at the forest edge.…”

Impacts of Habitat Degradation on Tropical Montane Biodiversity and Ecosystem Services: A Systematic Map for Identifying Future Research Priorities

“…For example, the effective of population sizes of the mountain white-eye (Zosterops poliogaster) in East Africa were higher in larger and interconnected forest patches (Husemann et al, 2015). Habitat fragmentation can also decrease fecundity in plants (Somanathan and Borges, 2000;Franceschinelli et al, 2015), which may be caused by a decrease in pollinator visits and an increase in seed predation (Franceschinelli et al, 2015). Fragmentation also resulted in reduced plant survival which could be attributed to higher desiccation and seedling predation (Alvarez-Aquino et al, 2004).…”