Epiphytic ferns in swamp forest remnants of the coastal plain of southern Brazil: latitudinal effects on the plant community

Abstract

Community structure and spatial distribution of epiphytic ferns in swamp forest remnants along the coastal plain of the state of Rio Grande do Sul were analyzed. A total of 440 trees were sampled in fi fty-seven 10 x 10 m plots. Each phorophyte was divided into fi ve ecological zones (strata), where all species of epiphytic ferns were recorded. A total of 34 species representing 18 genera in six families were recorded. Polypodiaceae was the most represented family with 17 species, and Microgramma vacciniifolia had the highest epiphytic importance value. Characteristic holoepiphyte was the predominant ecological category, representing 70 % of the species. Ordination analysis showed a gradual change in fl oristic composition between ecological zones with richness diff ering signifi cantly between strata. We observed that with increasing latitude there was a decrease in mean temperature and total rainfall, but an increase in frosts. Th ese climatic and phytogeography changes result in a reduction in species richness and a change in the structure of epiphytic fern communities in a north-to-south direction. Th e importance of swamp forest remnants of the coastal plain to the diversity of epiphytic ferns is discussed.

Catalogue of the vascular epiphytic flora of Uruguay

“…The lower orchid richness recorded in our study is in accordance with the strong north to south decrease of species and genera in eastern subtropical South America (Waechter 1998), extending from Paraná state (Brazil) to Buenos Aires province (Argentina). The same decreasing tendency was reported for epiphytic cacti (Bauer & Waechter 2011) and ferns (Gonzatti et al 2016;Machado et al 2016), and might also be explained by the decrease in average precipitation and temperature, and the concomitant increase of water deficit and number of frost days south of 30ºS (Barros et al 2006).…”

“…The predominance of this category has been often reported for epiphytic communities in moist subtropical climates (Gonçalves & Waechter 2003;Barbosa et al 2015;Machado et al 2016). Facultative holoepiphytes (HLF) represent a diverse taxonomic group, commonly varying according to the environmental characteristics, such as the abundance of rocky outcrops (walls or boulders) inside or adjacent to forests.…”

“…Geographic distribution data refers to the departments where the species were registered based on herbarium specimens and field observations, and is abbreviated as follows: Artigas: AR; Canelones: CA; Cerro Largo: CL; Colonia: CO; Durazno: DU; Flores: FS; Florida: FA; Lavalleja: LA; Maldonado: MA; Montevideo: MO; Pay: PA; Río Negro: RN; Rivera: RI; Rocha: RO; Salto: SA; San José: SJ; Soriano: SO; Tacuarembó: TA, and Treinta y Tres: TT. Additionally, the distribution in neighboring regions of Uruguay was investigated in order to detect the southernmost limit for each species; for this purpose we consulted several online databases (GBIF 2018; SPLink 2018; Flora do Brasil 2020 2019; IBODA 2019), publications concerning vascular epiphytes (Bauer & Waechter 2011;Perleberg et al 2013;Carneiro et al 2016;Gonzatti et al 2016;Machado et al 2016;Martínez et al 2016;Guerrero & Cellini 2017;Pellegrini 2018), and in some cases data from herbarium labels. Habitat distribution follows the forest classification previously described (see Study area).…”

“…Several authors documented the contribution of epiphytes to species richness, biological diversity maintenance, primary production and structure of these ecosystems (Gentry & Dodson 1987;Benzing 1990;Kersten 2010;Freitas et al 2016). Despite being a typical component of tropical wet forests, vascular epiphytes also occur in subtropical moist forests (Waechter 1998;Rogalski & Zanin 2003;Giongo & Waechter 2004;Machado et al 2016) and to a lesser extent in temperate moist forests (Zotz 2005;San Martín et al 2008;Pincheira-Ulbrich 2011). Additionally, some species could even be found in arid and semi-arid environments (Gentry & Dodson 1987).…”

An exquisitely preserved filmy fern (Hymenophyllaceae) from the Early Cretaceous of Mongolia

“…iwatsukii was an epiphyte based on the autochthonous deposition of the Tevshiin Govi and Tugrug lignites and the habit of most species of extant Hymenophyllum . In modern swamp forests, Hymenophyllum may occur in the high canopy (Zotz and Büche, 2000), but more typically is restricted to lower, more humid and shady strata, such as the base of tree trunks (Zotz and Büche, 2000; Machado et al, 2016). This reflects the environmental conditions needed for water absorption and drought intolerance in Hymenophyllaceae (Dubuisson et al, 2009, 2013).…”