Soil-vegetation relationships on a banded ironstone 'island', Carajás Plateau, Brazilian Eastern Amazonia

Abstract

Vegetation and soil properties of an iron-rich canga (laterite) island on the largest outcrop of banded-iron formation in Serra de Carajás (eastern Amazonia, Brazil) were studied along a topographic gradient (738-762 m asl), and analyzed to test the hypothesis that soil chemical and physical attributes play a key role in the structure and floristic composition of these plant communities. Soil and vegetation were sampled in eight replicate plots within each of the four vegetation types. Surface (0-10 cm) soil samples from each plot were analyzed for basic cations, N, P and plant species density for all species was recorded. CCA ordination analysis showed a strong separation between forest and non-forest sites on the first axis, and between herbaceous and shrubby campo rupestre on the second axis. The four vegetation types shared few plant species, which was attributed to their distinctive soil environments and filtering of their constituent species by chemical, physical and hydrological constraints. Thus, we can infer that Edaphic (pedological) factors are crucial in explaining the types and distributions of campo rupestre vegetation associated with ferruginous ironstone uplands (Canga) in Carajás, eastern Amazonia, therefore the soil properties are the main drivers of vegetation composition and structure on these ironstone islands.

Soil-vegetation relationships and community structure in a "terra-firme"-white-sand vegetation gradient in Viruá National Park, northern Amazon, Brazil

“…This species is also endemic in Brazil and widely distributed in all states (Sobral et al 2010); it has been reported for Campinaranas of the Serra do Cachimbo (PA) and Parintins (AM) , in the savannas of Roraima (Miranda and Absy 2000), in the transition Cerrado-flooded forest in São Paulo, in the Cerrado in Maranhão (Conceição and Aragão 2010), in rainforests in all states of the northeastern region (Nascimento et al 2010), and in montane shrub grassland in the Serra dos Carajás (Nunes et al 2015). However, E. puniciflora was not sampled in Campinaranas of Cruzeiro do Sul (AC) and Vigia do Nazaré (PA) (Ferreira 2009).…”

“…This genus is also observed in Campinaranas in Cantá (RR) and Cruzeiro do Sul (AC) (Ferreira 2009), and in "restinga" forest on the coast of São Paulo (Guedes et al 2006). The following species are also described for the Serra dos Carajás (PA), especially in forest fragments and forests on slopes (on the edge of the highland): Tapirira guianensis, Guatteria foliosa, Clusia panapanari, Sclerolobium paniculatum and Casearia javitensis (Nunes 2009, Nunes et al 2015.…”

Holocene history of a lake filling and vegetation dynamics of the Serra Sul dos Carajás, southeast Amazonia

“…1b). The occurrence of extensive lateritic crusts and low water retention allowed the widespread development of plant species adapted to nutrient and hydric stress and hindered the colonization of tree species (Porto and Silva 1989, Skirycz et al 2014, Nunes et al 2015. Consequently, small patches of forest (capão de mata) occur along structural features or over different lithologies that are much more sensitive to weathering and lead to the formation of a thicker soil horizon, with higher nutrient and water availability.…”

Brasilianthus (Melastomataceae), a new monotypic genus endemic to ironstone outcrops in the Brazilian Amazon

“…The word canga describes the open, rocky habitats with a savanna vegetation cover on iron ore outcrops that are nestled within the more widespread rainforest that covers much of the Carajás mountain range. Brasilianthus appears to grow only in these non-forest vegetation habitat islands that have been variously described as canga vegetation, banded ironstone formations (BIF), ferruginous shrubby or herbaceous campo rupestre, and even mettalophile savanna (Nunes et al 2015). Virtually all of the known collections come from habitats described as vegetação rupestre, campo graminoso on canga, and lake margins in canga.…”

“…Brazil's size, orogenic history, climatic fluctuations, and long history as part of an island continent have also figured prominently in promoting this diversity. For plants, at least, edaphic factors (abiotic influences relating to the physical or chemical composition of the soil) have also been a driving force in the adaptive differentiation of species and in the structure and composition of plant communities (Rajakaruna 2004;Nunes et al 2015).…”