Diversity and Genetic Structure of the Mexican Endemic Epiphyte Tillandsia achyrostachys E. Morr. ex Baker var. achyrostachys (Bromeliaceae)

Abstract

The F-statistic values (>0) and the level of gene flow found suggest that habitat fragmentation has broken up the former population structure. In this context, it is proposed that the host trees of T. achyrostachys should be considered as a conservation priority, since they represent the limiting factor to bromeliad population growth and connectivity.

Genetic diversity, genetic drift and mixed mating system in small subpopulations of Dyckia ibiramensis, a rare endemic bromeliad from Southern Brazil

“…This variety is the result of the habitat, effective size (Table 1), high levels of genetic diversity variation (Table 2) and significant genetic divergence among the subpopulations (Ĝ 0 ST ¼ 0:674). The overall genetic diversity of the species (Ĥ e ¼ 0:219) was high compared to other species of Bromeliaceae (Soltis et al 1987;Murawski and Hamrick 1990;Izquierdo and Piñero 2000;Sarthou et al 2001;González-Astorga et al 2004), monocotyledons in general (Hamrick and Godt 1989), and even in comparison with rare (Cole 2003) and endemic species (Hamrick and Godt 1989;Godt and Hamrick 1996). According to Leimu et al (2006), hybridization, recent speciation, multiple origins or recent population bottlenecks may result in high levels of genetic variation in rare species.…”

Experimental evidence of an increased leaf production in Prosopis after removal of epiphytes (Tillandsia)

“…Distribution and structure of trees is interacting also with the epiphytes colonizing on them. Data on the genetic structure of populations of Tillandsia achyrostachys, an endemic bromeliad of the tropical dry forests of Mexico, suggest that habitat fragmentation has reduced allelic richness and genetic diversity, and increased significant genetic differentiation between populations (González-Astorga et al, 2004). Some Tillandsia species are good biomonitors for different anthropogenic activities as vehicular emissions, industrial and agricultural activities (Bermudez et al, 2009;Pignata et al, 2002;Wannaz et al, 2006).…”

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

“…Tillandsias tend to occur in relatively high numbers on large- and medium-sized trees (Sáyago et al 2013); therefore, the overall reward obtained by visiting multiple flowers on the same host tree possibly provides enough energy to hummingbird pollinators. This behaviour might cause limited pollen movement within forest fragments, high genetic structuring, and low gene flow between populations, a genetic pattern that has been observed in vertebrate-pollinated epiphytic bromeliads in fragmented habitats (González-Astorga et al 2004; Paggi et al 2015). Similarly, the foraging behaviour of stingless bees may promote self-pollination in forest fragments where these bees are more abundant; however, the genetic consequences associated with changes in pollinator composition and behaviour in fragmented landscapes are still unknown for Mexican dry forest tillandsias.…”

“…Feinsinger 1978). The few studies available on epiphytic bromeliads indicate low genetic variation and low outcrossing rates, in addition to limited gene flow and restricted neighbourhoods, particularly in self-pollinating species (Soltis et al 1987; Gonzalez-Astorga et al 2004; Cascante-Marín et al 2014); however, for T. makoyana these ideas remain elusive. Another potential explanation for the reduced seed set of T. makoyana in forest fragments is that greater attack by herbivores and pathogens in forest fragments would lower resources for reproduction or directly affect the developing seeds.…”

“…Epiphytes are considered particularly sensitive to habitat disturbance because they have low growth rates, delayed sexual maturity, limited seed dispersal and recruitment, and no seed bank (Turner et al 1994; Martin et al 2004; Cascante-Marín et al 2009). In terms of habitat fragmentation, most studies on epiphytic plants show that the abundance, diversity, growth, dispersal and genetic parameters of epiphytes are negatively affected by fragmentation (González-Astorga et al 2004; Flores-Palacios and García-Franco 2004; Werner and Gradstein 2008, 2009; Aguirre et al 2010). This has been related to the dependence of epiphytes on their host trees, which makes epiphytes vulnerable to changes in the availability and traits of their phorophytes (Magrach et al 2012; Sáyago et al 2013).…”