Cerrados in Argentina? Structure, diversity and biogeography of the woody component of a savanna in the Misiones Province

Abstract

The Teyú Cuaré field, in Misiones province, Argentina, has been renowned for its flora and physiognomy, which led researchers to indicate that it could be a relict of Cerrado biome. We analyzed the floristic structure of the woody component of a savanna community in this site, and discussed the processes that could contribute to the permanence of this vegetation type over time. Perimeter and height of all woody individuals ≥ 10 cm of perimeter at soil height were collected in 12 square plots (400 m2 each one). We found 15 families and 17 species in our site and compared the woody flora surveyed at this site with the flora of other Cerrado áreas from Brazil and Paraguay. Leptolobium elegans had the highest importance value. The woody flora of the área is closely related to the Cerrado areas from Paraná state in Brazil and Canindeyú and Amambay in Paraguay. This site probably reflects old open physiognomies which were predominant in Misiones and Southern of Brazil in the late Pleistocene and middle Holocene. We inferred that the permanence of open physiognomies at Teyú Cuaré is probably related to mechanisms that act at different levels, such as geological, edaphic, anthropic, and fire disturbance.

Pequeños pero importantes: las comunidades de vegetales leñosa de los afloramientos de arenisca de Teyú Cuaré (Misiones, Argentina).

“…Because of its presence, these sites has high conservation values for this species in the Osununú Private Reserve. This species was the most important in the Teyu Cuaré savanna (Velazco et al, 2018) Cordiera concolor is a small tree characteristic of dense and mixed ombrophilous forest, as well as of natural forest patches on grassland from Brazil, Paraguay and Argentina (Bacigalupo, 1960;Delprete et al, 2004). In the last country, this species was recorded only in the San Ignacio municipality and is considered as exclusive to this region (Biganzoli & Romero, 2004).…”

“…In the region, the savanna soil is nutrient poor with a sandy texture, while in the rupestrian environment the soil is scarce (see appendix in Velazco 2014). Fire is frequent in savanna (Velazco et al, 2018), so only fire-resistance species can prevail in that environment. Fire and soil are common factors that determine structure and composition of communities in rupestrian and savanna vegetation (Abadia et al, 2018;Fernandes, 2016;Dantas et al, 2015).…”

“…The abundance of Ocotea lancifolia denotes its capacity to live in this kind of site, although it was recorded in low frequency in local savanna and forest (Velazco et al, 2015;Velazco et al, 2018).…”

“…We compared the rupestrian community with the neighbor forest and savannas formation (Velazco et al, 2015, Velazco et al, 2018. Such comparisons were based on diversity profile (Jost, 2006) and beta diversity (Podani & Schmera, 2014) approaches.…”

“…San Ignacio's flora, in Misiones province (Argentina), have attracted the botanical community, not only because of restricted plant distribution and endemic species, but also for its physiognomy, which previous researchers claim to represent a fragment of Brazil's Cerrado biome (Chébez, 1996;Biganzoli & Romero 2004;Velazco et al, 2018). The singularities of this region are not restricted to its flora, but also to geomorphology, derived from the sandstone outcrops of Solari Formation, a remarkable characteristic of the province since the most of its surface is covered by extrusive magmatic stones of the Serra Geral Formation (Aceñolaza, 2017).…”