Ramet demography of Aechmea distichantha (Bromeliaceae) in two contrasting years in the understory and open areas of a South American xerophytic forest

Abstract

The Schinopsis balansae forests of the Wet Chaco are characterized by convex areas with woody vegetation and plain areas with herbaceous vegetation. In the Wet Chaco, Aechmea distichantha is a terrestrial bromeliad that forms dense colonies in the understory and open areas of these forests. The aim of this study was to analyze the spatial and temporal variations in population dynamics of this bromeliad species. We monitored ramets growing in sun and shade conditions during two contrasting years. We analyzed the spatial and temporal variations in survival, flowering, and ramet production. Variations in survival, flowering, and ramet production were more marked between years than between habitats. During the year with wetter and milder temperature conditions, survival and ramet production were higher than during the drier year with more extreme temperatures. Survival of vegetative ramets was less variable than survival of young and reproductive ramets. In the colder year, lower winter temperatures reduced the populations in all stages, being more important in the open areas. Our results highlight the importance of low temperatures on A. distichantha demography at this xerophytic forest located at the southernmost distribution range of this bromeliad species.

Demographic structure of clonal, endemic, and endangered rheophyte bromeliad Dyckia ibiramensis: asexual vs sexual reproduction

“…(Mondragón et al 2004), in Aechmea distichantha Lem. (Barberis et al 2020) and in D. brevifolia Rogalski et al 2017) Our results confirm Harper's review (1977) of the dynamics of perennial herbaceous populations, suggesting that recruitment via seeds contributes little to the maintenance of populations. Plants with sexual origin have a higher mortality rate and lower levels of success in the establishment (Zhang & Zhang 2007).…”

“…Drought was considered the main cause of death during the early stages of development of epiphytic bromeliads (Benzing 1981;Mondragón et al 2004; Rodriguésia 72: e00752020. 2021 Zotz et al 2005), as well, very low temperatures in A. distichantha (Barberis et al 2020). In the case of D. ibiramensis, besides lack of water, lack of nutrients and floods may also cause death, because they are not yet attached to the rock.…”

“…Besides, it is likely that the variation in rosette size of the species also occurs as a function of light intensity (fully exposed or in shadow of the sarandis). For vegetative ramets, plant survival was higher in the shade than in the sun; and the higher flowering of ramets in the shade is probably associated with milder conditions in the understory (Barberis et al 2020).…”

Demographic structure across all known populations of the rheophyte Dyckia brevifolia Baker (Bromeliaceae) in the Itajaí-Açú River, Southern Brazil

“…In this study, it was found that rosettes in full sun were smaller (diameter of rosettes) than those under the 'sarandis' (shrubs of thin and exible stems of the banks of rivers) (J. M. Rogalski, personal observation). According Barberis et al (2020) for vegetative ramets, plant survival was higher in the shade than in the sun; and the higher owering of ramets in the shade is probably associated with milder conditions in the understory.…”

Biogeography of different life forms of the southernmost neotropical tank bromeliad

“…The disposition of the foliar bases produces a well-developed phytotelma that allows the accumulation of water and litter (Cavallero et al, 2009(Cavallero et al, , 2011, where a diverse aquatic community develops (Montero et al, 2010). This species mainly reproduces asexually, but sexual reproduction ensures the colonization of new patches (Barberis et al, 2014(Barberis et al, , 2020Brown, 1990). It is pollinated by birds and insects (Bianchi et al, 2000;Freire et al, 2018), and its fruits are consumed and dispersed by birds and mammals (Blendinger et al, 2015).…”