Phylogenetic structure is determined by patch size in rock outcrop vegetation on an inselberg in the northern Amazon region

Granite outcrops are globally widespread habitat islands that harbour naturally fragmented areas of vegetation in ‘pockets’ of soil. These habitats are ideal for investigating the drivers of biogeographic patterns at different scales. However, beyond the tropics, understanding of the environmental drivers of community composition within and between these ‘island on islands’ is limited. In this study, we determined within‐ and between‐outcrop patterns of plant biodiversity in the Southwest Australian Floristic Region – a global biodiversity hotspot. We measured plant community composition of soil‐patches on nine granite outcrops. Outcrop floristic composition was mostly controlled by geographic location and outcrop topography (slope and aspect‐northness), whereas plant community diversity (richness, abundance, evenness and Simpson diversity) was strongly controlled by soil‐patch size, regardless of outcrop location or size. Outcrops with larger soil‐patches hosted greater plant diversity on those soil‐patches. Effective conservation of outcrops should focus on protecting the fragile soil communities on multiple rock outcrops at a regional scale to allow for the continuing persistence of extraordinary biodiversity in these regions.

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“…1999; Villa et al . 2018). We found this to hold also true for the soil island micro‐habitats studied here.…”

Section: Discussionmentioning

confidence: 99%

“…2015; Villa et al . 2018). For example, resurrection plant B. constricta was present on 90% of the twenty largest soil islands but present on 10% of the twenty smallest.…”

Section: Discussionmentioning

confidence: 99%

Multi‐scale biogeographic controls over plant communities on granite outcrops in the Southwest Australian Floristic Region

Clark-Ioannou¹,

Wardell‐Johnson²,

Millett

2021

Austral Ecology

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“…de Paula et al 2015;Porembski et al 2000). Thus, at a local scale, environmental filtering favors the presence of plant communities phylogenetically clustered in rock outcrops (Villa et al 2018;Parmentier & Hardy 2009).…”

Section: Introductionmentioning

confidence: 99%

Novelties from the herbaceous stratum in a key region for the conservation of the Southern Amazon

et al. 2022

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The contribution of the herbaceous stratum to tropical plant diversity is considerable, however this component remains undersampled. We investigated floristic, structural, ecological and conservation issues concerning the herbaceous component of a seasonal deciduous forest associated with granitic rock outcrops in the Cristalino Region, a key area for biodiversity conservation in the Brazilian Amazon. We installed a permanent plot of 1 ha, allocating 10 transect-lines of 20 m each. We identified the sampled individuals, measured height and projection, and verified cover and frequency per species, genera and family. We recorded 86 species, 62 genera and 25 families, with Orchidaceae being the family with the highest species richness. Among the 26 new species added to Cristalino Flora, we included Philodendron deflexum Poepp. ex Schott and Griffinia nocturna Ravenna, the latter ‘Critically Endangered’. Furthermore, the occurrence of G. nocturna in an Amazonian forest matrix is a novelty in this study. The estimate of species diversity according to Shannon-Wiener (H’) was 2.43 nats.ind.-1 (equivalent to 11.37 ± 0.90 IC95% equally common species), and according to Simpson (1/D), 6.82 (± 0.648 IC95%). The rarefaction and extrapolation curves for the diversity estimates tended to stabilize. Although the vegetation on rock outcrops usually presents a high number of endemic species, this pattern was not found in our study area, which can be explained by its continuous occurrence in the forest matrix. The understory of our study area consists in a mixture of floras, being composed mainly of species from the Amazon and/or Cerrado biomes. In view of the current anthropic pressure faced by the southern Amazon, we reinforce the importance of carrying out inventories of its herbaceous communities, since the risk of species loss is even more alarming when considering present undersampling of this component.

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“…low nutrient or water availability, high radiation levels and large temperature amplitude); only certain plant species, with morphological and ecophysiological adaptations, can tolerate such conditions (Lüttge 1997;Bremer & Sander 2000;Biedinger et al 2000;Porembski 2007). These species consequently have a restricted geographic distribution with a considerable number being endemics (Barthlott et al 1993;Porembski et al 2000a;Seine et al 2000;Porembski 2007) and predominantly create patchy vegetation formations (Porembski 2007;de Paula et al 2016;Villa et al 2018b).…”

Section: Introductionmentioning

confidence: 99%

The pattern of high plant diversity of Neotropical inselbergs: highlighting endemic, threatened and unique species

et al. 2020

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Understanding how multiple drivers shape plant community diversity across environmental gradients is one of the most important issues in plant ecology and biodiversity conservation. We aimed to analyse plant community structure and diversity in four inselbergs in Espírito Santo State, Brazil. We evaluated species diversity, floristic composition and similarity, phytosociological structure, occurrence, and conservation status of rupicolous flora in the inselberg communities. We used field expeditions and plant inventory data from 370 sampling units. We estimated floristic similarity and compared diversity indexes among inselbergs. We observed marked differences in community structure and diversity among inselbergs, where the southern region had the highest number of taxa and higher values of diversity indices. There were also notable differences in floristic composition and phytosociological structure, with a decrease in similarity as geographical distance increased. This finding demonstrated the existence of differences in the patterns of dominance and vegetation cover along the latitudinal gradient, as well as differences in endemic, threatened, and exclusive species, and represents a first step toward establishing criteria for biodiversity conservation for inselbergs in Espírito Santo State.

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Phylogenetic structure is determined by patch size in rock outcrop vegetation on an inselberg in the northern Amazon region

Cited by 12 publications

References 43 publications

Multi‐scale biogeographic controls over plant communities on granite outcrops in the Southwest Australian Floristic Region

Multi‐scale biogeographic controls over plant communities on granite outcrops in the Southwest Australian Floristic Region

Novelties from the herbaceous stratum in a key region for the conservation of the Southern Amazon

The pattern of high plant diversity of Neotropical inselbergs: highlighting endemic, threatened and unique species

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