Islands in a green ocean: Spatially structured endemism in Amazonian white‐sand vegetation

Costa, Fábio Medeiros da; Terra-Araújo, Mário Henrique; Zartman, Charles E.; Cornelius, Cíntia; Carvalho, Fernanda Antunes; Hopkins, M. J. G.; Viana, Pedro Lage; Prata, Eduardo Magalhães Borges; Vicentini, Alberto

doi:10.1111/btp.12732

Cited by 27 publications

(18 citation statements)

References 59 publications

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“…There is a large turnover of species between outcrops (Zappi et al 2019;Fonsecada-Silva et al 2020) and very few species are widely distributed across these disjunct, isolated habitats. Similar to what was found by (Costa et al 2019) in Amazonian White Sand Campinas, the isolation of the patchy canga outcrops limits dispersal and increases floristic differentiation, and the adverse conditions, such as high temperature, extreme exposure to sunlight and winds, and a relatively well defined dry season represent ecological filters for the species that occupy the canga, partly explaining the high number of endemic species in the CRC of Carajás.…”

Section: Floristic Composition Of Serra De Campos × Other Canga Outcropssupporting

confidence: 65%

“…(Viana et al 2016;Mota et al 2018;Zappi et al 2019). There are also island-like lowland ecosystems, such as white sand campinaranas, savannas, and low elevation granitic domes or inselbergs, associated with arenitic and often waterlogged soil in the Amazon region (Gröger and Huber 2007;Adeney et al 2016;Costa et al 2019;Henneron et al 2019;Devecchi et al 2020).…”

Section: Introductionmentioning

confidence: 99%

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Iron islands in the Amazon: investigating plant beta diversity of canga outcrops

Andrino¹,

Barbosa-Silva²,

Lovo³

et al. 2020

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The world’s largest mineral iron province, Serra dos Carajás, is home to an open vegetation known as canga, found on top of isolated outcrops rising out of the Amazon rainforest. Over one thousand vascular plants species have been recorded in these canga sites, including 38 edaphic endemics. A new survey adds to our investigation of biogeographic relationships between sixteen canga outcrops and the effect of the distance between site pairs on the number of shared species, regional species turnover and species distribution patterns. Plant collecting expeditions to the westernmost site, the Serra de Campos of São Félix do Xingu (SFX), were carried out followed by the identification of all collected specimens and the creation of a species database, built to perform biogeographical analyses. Floristic relationships among the sites were investigated regarding their similarity, using multivariate analyses. The correlation between canga areas and species richness was tested, as well as the geographical distance between pairs of outcrops and their shared species. Vascular plants at SFX total 254 species including 17 edaphic endemics. All canga sites are grouped with 25% of minimum similarity, and the SFX falls within a large subgroup of outcrops. The total species number shared between site pairs does not change significantly with geographical distance but is positively correlated with the area of each outcrop. Meanwhile, shared endemic species numbers between site pairs decline when geographical distance increases, possibly imposed by the barrier of the rainforest. Our data suggest higher shared similarity between the largest and species-richest sites as opposed to geographically nearby sites, and provide useful insight for drafting conservation and compensation measures for canga locations. The size of the canga outcrops is associated to higher floristic diversity but connectivity among islands also plays a role in their similarity.

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Section: Floristic Composition Of Serra De Campos × Other Canga Outcropssupporting

confidence: 65%

Section: Introductionmentioning

confidence: 99%

Iron islands in the Amazon: investigating plant beta diversity of canga outcrops

Andrino¹,

Barbosa-Silva²,

Lovo³

et al. 2020

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“…Sampling was conducted in the two main forest types of nonflooded tropical lowland rain forests: upland ( terra firme ) and white‐sand ( campinarana ) forests. White‐sand forests have long been identified as island‐like formations (Costa et al ., 2019) of the most acidic and nutrient‐poor soils known, surrounded by rainforests growing on more typical soils. They have captured the attention of biologists who have hypothesized that they represented laboratories of evolution producing a unique white‐sand fauna and flora characterized by unusual structure, function, and species compositions (Fine & Baraloto, 2016).…”

Section: Methodsmentioning

confidence: 99%

What do tropical cryptogams reveal? Strong genetic structure in Amazonian bryophytes

et al. 2020

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Lowland tropical bryophytes have been perceived as excellent dispersers. In such groups, the inverse isolation hypothesis proposes that spatial genetic structure is erased beyond the limits of short-distance dispersal. Here, we determine the influence of environmental variation and geographic barriers on the spatial genetic structure of a widely dispersed and phylogenetically independent sample of Amazonian bryophytes. Single nucleotide polymorphism data were produced from a restriction site-associated DNA sequencing protocol for 10 species and analyzed through F-statistics and Mantel tests. Neither isolation-by-environment nor the impact of geographic barriers were recovered from the analyses. However, significant isolation-by-distance patterns were observed for 8 out of the 10 investigated species beyond the scale of short-distance dispersal (> 1 km), offering evidence contrary to the inverse isolation hypothesis. Despite a cadre of life-history traits and distributional patterns suggesting that tropical bryophytes are highly vagile, our analyses reveal spatial genetic structures comparable to those documented for angiosperms, whose diaspores are orders of magnitude larger. Dispersal limitation for tropical bryophytes flies in the face of traditional assumptions regarding their dispersal potential, and suggests that the plight of this component of cryptic biodiversity is more dire than previously considered in light of accelerated forest fragmentation in the Amazon.

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“…White-sand shrub and grassland patches, hereafter campinas, are naturally fragmented and resemble islands in a "sea" of forests, growing on nutrient-poor soils (Prance 1996;Fine et al 2010;Ritter et al 2018;Costa et al 2020;Capurucho et al 2020a). Campina patches cover approximately 1.6% of the Amazon basin (Adeney et al 2016), yet are an important Amazonian island-like system, harboring a unique biota (Borges et al 2016a;Costa et al 2020;Capurucho et al 2020a). Landscapes with campina patches have different spatial configurations throughout Amazonia, composed of large and connected patches in the north and small and isolated patches in the south (Borges et al 2016a).…”

Section: Introductionmentioning

confidence: 99%

Landscape configuration of an Amazonian island-like ecosystem drives population structure and genetic diversity of a habitat-specialist bird

Ritter

Ribas

Menger

et al. 2020

Preprint

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ContextAmazonian white-sand ecosystems (campinas) are open vegetation patches which form a natural island-like system in a matrix of tropical rainforest. Due to their clear distinction from the surrounding matrix, the spatial characteristics of campina patches may affect the genetic diversity and composition of their specialized organisms such as the small and endemic passerine Elaenia ruficeps.ObjectivesHere, we estimate the relative contribution of the current extension, configuration and geographical context of campina patches to the patterns of genetic diversity and population structure of E. ruficeps.MethodsWe sampled individuals of E. ruficeps from three landscapes in Central Amazonia with contrasting campina spatial distribution, from landscapes with large and connected patches to landscapes with small and isolated patches. We estimate population structure, genetic diversity, and contemporary and historical migration within and among the three landscapes and used landscape metrics as predictor variables. Furthermore, we estimate genetic isolation by distance and resistance among individuals sampled within landscapes.ResultsWe identified three genetically distinct populations with asymmetrical gene flow among landscapes and a decreasing migration rate with distance. Within each landscape, we found low genetic differentiation without genetic isolation by distance nor by resistance. In contrast, we found differentiation and spatial correlation between landscapes.ConclusionsOur results uncover population dynamics of E. ruficeps through time. Together with previous studies, this suggests that both regional context and landscape structure shape the connectivity among populations of campina specialist birds, and that Amazonian landscapes, together with their associated biota, have responded to recent climatic changes.

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Islands in a green ocean: Spatially structured endemism in Amazonian white‐sand vegetation

Cited by 27 publications

References 59 publications

Iron islands in the Amazon: investigating plant beta diversity of canga outcrops

Iron islands in the Amazon: investigating plant beta diversity of canga outcrops

What do tropical cryptogams reveal? Strong genetic structure in Amazonian bryophytes

Landscape configuration of an Amazonian island-like ecosystem drives population structure and genetic diversity of a habitat-specialist bird

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