Caudex growth and phenology of Cyathea atrovirens (Langsd. & Fisch.) Domin (Cyatheaceae) in secondary forest, southern Brazil

Abstract

The leaf production and senescence, formation and release of spores of Cyathea atrovirens (Langsd. & Fisch.) Domin were analysed based on the monthly monitoring of 50 plants growing in a secondary forest, in the municipality of Novo Hamburgo, in the state of Rio Grande do Sul, during the year 2004. The caudex height and number of mature and fertile leaves were recorded annually in 2004-09. In 2004, monthly production and senescence of leaves were concomitant, without total leaf abscission. Population synchrony at emergence (Z = 0.86) and leaf senescence (Z = 0.82) increased in spring but did not correlate with temperature and photoperiod. All individuals were fertile and the sporangia production and spore liberation presented higher and equal synchrony (Z = 0.84) respectively in spring and summer. Sporangia production was related with temperature and photoperiod, however taller plants did not produce more fertile leaves. Phenological events analysed were not influenced by precipitation, as expected for forests in non-seasonal climate. Over five years (2004-09), the annual mean caudex growth varied between 1.19 and 2.50 cm.year -1 and the plants appeared to have an ability to maintain a relatively stable amount of leaves throughout this period.Keywords: monitoring, growth rates, tree fern. Palavras-chave: monitoramento, taxas de crescimento, samambaia arborescente. Crescimento do cáudice e fenologia de

Phenology, caudex growth and age estimation of Cyathea corcovadensis (Raddi) Domin (Cyatheaceae) in a subtropical forest in southern Brazil

“…It is likely that the variation of approximately 3.5 h in the photoperiod over the course of a year in the coastal region of Rio Grande do Sul, together with the direct effects of changes in temperature, triggers predictable physiological responses in several species (Marchioretto et al 2007), as was observed for C. corcovadensis in the present study, as well as and for C. atrovirens and Dicksonia sellowiana in the studies conducted by Schmitt et al (2009) and Schmitt & Windisch (2012), respectively. In a study of 16 fern species in a subtropical broadleaf forest in northeastern Taiwan, Lee et al (2009) reported that leaf senescence, spore maturation and spore release all presented significant positive correlations with temperature but not with precipitation, which is in agreement with our findings for C. corcovadensis.…”

“…The mean annual number of mature leaves was equivalent among the three years evaluated. Therefore, tree ferns seem able to maintain a relatively stable number of leaves over a long period of time, as observed for Dicksonia sellowiana (Schmitt et al 2009) and C. atrovirens (Schmitt & Windisch 2012).…”

“…This more continuous pattern of leaf emergence and senescence, albeit irregular, has also been reported for C. delgadii Sternb. (Schmitt & Windisch 2007) and C. atrovirens (Schmitt & Windisch 2012) in Rio Grande do Sul, probably because of the similar weather patterns.…”

“…In tree ferns, the growth of the caudex (perennial stem) varies greatly according to the habitat, and some species grow very slowly, as recorded by Schmitt & Windisch (2012) , as reported for C. trichiata (Maxon) Domin (Bittner & Breckle 1995). Tree ferns constitute a special case, because they have vertical caudices on which leaf scars may provide evidence of the history of leaf emergence (Sharpe & Mehltreter 2010).…”

“…Therefore, tree fern age can be estimated by measuring the increase in caudex height and assessing leaf emergence rates (Tanner 1983;Schmitt & Windisch 2006b;Sharpe & Mehltreter 2010). In the Neotropics, studies including phenological data, caudex growth rates and age estimates for Cyatheaceae, restricted to a few species and sites, were conducted by Mehltreter & García-Franco (2008), in Mexico; by Conant (1976), Seiler (1981), Tanner (1983) and Bittner & Breckle (1995), in Central America; by Ortega (1984), Arens & Baracaldo (2000) and Arens (2001), in South America; and by Schmitt & Windisch (2001;2003;2006a;2006b;, 2012 and Lehn & Leuchtenberg (2008), in southern Brazil.…”