Deforestation is the turning point for the spreading of a weedy epiphyte: an IBM approach

Abstract

The rapid spread of many weeds into intensely disturbed landscapes is boosted by clonal growth and self-fertilization strategies, which conversely increases the genetic structure of populations. Here, we use empirical and modeling approaches to evaluate the spreading dynamics of Tillandsia recurvata (L.) L. populations, a common epiphytic weed with self-reproduction and clonal growth widespread in dry forests and deforested landscapes in the American continent. We introduce the TRec model, an individual-based approach to simulate the spreading of T. recurvata over time and across landscapes subjected to abrupt changes in tree density with the parameters adjusted according to the empirical genetic data based on microsatellites genotypes. Simulations with this model showed that the strong spatial genetic structure observed from empirical data in T. recurvata can be explained by a rapid increase in abundance and gene flow followed by stabilization after ca. 25 years. TRec model’s results also indicate that deforestation is a turning point for the rapid increase in both individual abundance and gene flow among T. recurvata subpopulations occurring in formerly dense forests. Active reforestation can, in turn, reverse such a scenario, although with a milder intensity. The genetic-based study suggests that anthropogenic changes in landscapes may strongly affect the population dynamics of species with ‘weedy’ traits.

Surrounded by Concrete: Genetic Isolation of Tillandsia Recurvata L. in an Urban Landscape in South-Eastern Brazil

“…Evidence has shown that inbreeding depression and population differentiation then become more likely, under the pressure of sustained dispersal limitations between isolated populations (Wright et al 2013). As such, low connectivity would be expected in urban landscapes, as well as high spatial genetic structure (SGS) (Chaves et al 2021).…”

“…The majority (24 or 80%) of them have discussed epiphyte population genetics in the context of microsatellite marker cross-ampli cation and species biology. The remaining papers (6 or 20%) investigated the population genetics of epiphytes in relation to fragmented landscapes, such as rural sites (Chaves et al 2018(Chaves et al , 2021; Aoki-Gonçalves et al 2020), industrial mining sites (Lavor et al 2014) and modi ed natural forests or reserves (Alcantara et al 2006;Goetze et al 2015). From these six aforelisted papers, contrasting outcomes of landscape fragmentation were reported for epiphyte genetic structure, largely dictated by the variety of taxonomic groups and breeding strategies that have been described.…”

“…From these six aforelisted papers, contrasting outcomes of landscape fragmentation were reported for epiphyte genetic structure, largely dictated by the variety of taxonomic groups and breeding strategies that have been described. For instance, sel ng epiphytes typically showed population differentiation and high inbreeding in fragmented landscapes (Chaves et al 2018(Chaves et al , 2021. In contrast, self-incompatible epiphytes show low SGS and high gene ow, although this connectivity appears to be dependent on an effective pollination strategy (Alcantara et Aoki-Gonçalves et al 2020).…”

“…This taxonomic bias is likely the result of the wide distribution and high abundance of many bromeliad species throughout the Neotropics (Paula et al 2016). More speci cally, Tillandsia recurvata L., has been featured most frequently in fragmentation studies (Chaves et al 2018(Chaves et al , 2021, as well as broader investigations of epiphyte population genetics (Soltis et al 1987;Solózano et al 2010). This concerted focus on T. recurvata may be determined by several key factors.…”

“…Moreover, this atmospheric bromeliad has been characterised as one of the most adaptable plants in the Western Hemisphere (Foster et al 1945), with valuable xerophytic qualities, such as small leaf size, CAM photosynthesis and absorbent leaf scales. T. recurvata also exhibits opportunistic traits, such as sel ng and high growth rates, which have allowed this species to reach extreme levels of abundance within fragmented landscapes, such as urban areas (Benzing 1980;Soltis et al 1987;Chaves et al 2021). As such, these traits make T. recurvata an ideal model to investigate the connectivity and genetic structure of epiphytic plants within understudied urban ecosystems.…”