Granite Inselbergs Research Articles

Use of eDNA and conventional sampling methods to survey rock pool (gnamma) biodiversity on granite inselbergs

AbstractSampling of environmental DNA (eDNA) and high‐throughput sequencing is emerging as an effective biodiversity assessment method in aquatic systems and may have utility for biodiversity inventory in terrestrial environments. Rock pools (gnammas) on granite inselbergs support a rich community of aquatic organisms and are culturally important to Indigenous peoples worldwide. However, the application of eDNA to survey rock pool biodiversity are undocumented. In a collaborative study with traditional owners, we explore the application of eDNA metabarcoding and traditional sampling methods to document and compare species richness and composition of eukaryotes from 15 rock pools (pits and pans) on granite inselbergs in southeastern Australia. We detected 116 taxonomic units, 81 assignments from eDNA sequencing and 35 species (23 rotifers and 12 microcrustaceans) using microscopic analysis. eDNA detected a broad range of taxa not previously documented from rock pools in Australia, although significantly more zooplankton (rotifers and microcrustaceans) were detected under a microscope, including several rare species and two undescribed species of rotifer. Brachionus calyciflorus and B. angularis were the only rotifer species assigned to species level through eDNA sequencing and were detected using both methods. We found no significant difference in mean species richness between rock pool types; however, species composition differed significantly between pits and pans. This study highlights the value of using eDNA to document biodiversity of ephemeral aquatic habitats in terrestrial ecosystems but reveals the general lack of reference sequence data for microorganisms, underscoring the value of using traditional sampling and taxonomic assignment methods.

Praxelis cleggiae (Compositae: Eupatorieae: Praxeliinae), a new species from the granite inselbergs in the east of the Departamento de Santa Cruz, Bolivia

SummaryPraxelis cleggiae (Compositae: Eupatorieae: Praxeliinae) is described and illustrated from the granite inselbergs (upon which it is most common), and on road crown chippings on old roads, in the Departamento de Santa Cruz, Bolivia; it has a disjunct distribution and is also found on the Serranía San Simón, in the San Ignacio Schist belt, Departamento de Beni. Material of this species was mostly determined as P. insignis (Malme) R.M.King & H.Rob., a Brazilian species, described from the metamorphosed sandstone of what is now the Parque Nacional da Chapada dos Guimarães in Mato Grosso State. The two species have some superficial resemblance, but differ significantly in plant size, internode length (relative to leaf length), branching, leaf shape and size, phyllaries, achenes and pappus. The total number of species of Praxelis recognised in Bolivia is now seven, and 20 species in the genus worldwide.

Inselbergs shaped by collapse: considerations on the structural control on granitic scarps

Inselbergs characterised by fracturing features correspond to the geomorphological manifestation of break-up of the rock mass and collapse. The steep slopes partially covered by angular boulders scattered chaotically reveal, in evolutionary terms, the predominance of the morphostructural controls, given by the presence of veins/dikes, sheeting joints, and vertical fractures. These structural planes in turn create anisotropies guiding fracturing directions and rockfall. In this work, we propose a model of geomorphological evolution of granitic inselbergs subjected to a structural propensity to fracturing. For this purpose, we analysed the Pedra da Galinha Choca inselberg (PGC) and Pedra Faladeira (Quixadá, NE of Brazil) inselbergs, whose morphologies attest to mechanical disintegration processes. Data extraction and interpretation were based on fieldwork and UAV photogrammetry, which provided products such as high-resolution models, orthomosaic, and DEM. Networks of multidirectional fractures were observed to promote an arrangement of interlocking blocks, allowing the maintenance of steep slopes (>60°), in which solutional features tend to be incipient due to the structural instability promoting collapse. Thus, the main features on the hillslopes are cavities like collapse tafone (CT) and large collapsed boulders (LCB). As a result of this structural setting, the inselberg displays sharp outlines, steep slopes, and wide talu deposits.

A biogeographical appraisal of the threatened South East Africa Montane Archipelago ecoregion

Recent biological surveys of ancient inselbergs in southern Malawi and northern Mozambique have led to the discovery and description of many species new to science, and overlapping centres of endemism across multiple taxa. Combining these endemic taxa with data on geology and climate, we propose the ‘South East Africa Montane Archipelago’ (SEAMA) as a distinct ecoregion of global biological importance. The ecoregion encompasses 30 granitic inselbergs reaching > 1000 m above sea level, hosting the largest (Mt Mabu) and smallest (Mt Lico) mid-elevation rainforests in southern Africa, as well as biologically unique montane grasslands. Endemic taxa include 127 plants, 45 vertebrates (amphibians, reptiles, birds, mammals) and 45 invertebrate species (butterflies, freshwater crabs), and two endemic genera of plants and reptiles. Existing dated phylogenies of endemic animal lineages suggests this endemism arose from divergence events coinciding with repeated isolation of these mountains from the pan-African forests, together with the mountains’ great age and relative climatic stability. Since 2000, the SEAMA has lost 18% of its primary humid forest cover (up to 43% in some sites)—one of the highest deforestation rates in Africa. Urgently rectifying this situation, while addressing the resource needs of local communities, is a global priority for biodiversity conservation.

A new genus and endangered species of euptychiine butterfly from isolated mountains in southeastern Brazil (Lepidoptera: Nymphalidae: Satyrinae).

Agojie rupicola gen. et sp. nov., a new genus and species of Euptychiina from the campos rupestres and granitic inselbergs of eastern Minas Gerais, southeastern Brazil, is herein described using comparative morphology and ecological data. Diagnoses, photos, and illustrations are also provided, in addition to a discussion on the putative systematic placement of the new taxa and its conservation status. Considering the collecting points, the estimated value for the extent of occurrence (EOO) is 100.263 km2 and the area of occupancy (AOO) is 20 km2, which combined with the reduced number of localities in which the species is known to occur, and the observed continuing decline of the quality of the habitat, we recommend that A. rupicola gen. et sp. nov. should be formally assessed as Endangered based on criteria B1+2(a,biii) of the International Union for Conservation of Nature (IUCN). The results presented here add to the increasing faunistic and floristic novelties that justify the priority for the conservation of these still scientifically underexplored Brazilian mountains.

Granitic inselberg erosion controlled by dike swarm array in semiarid Brazil

Numerous inselbergs rise above the regional erosional surface in semiarid northeastern Brazil. The inselbergs are underlain by the Quixadá Pluton and cut by cm-thick granite dike swarms. Five inselbergs with abundant dikes from two different parts of the pluton were selected to investigate the role of dike patterns in the evolution of residual granite topography, including morphological features of hillslopes. The methods included field mapping of landforms, structural measurements of accessible dike arrays, and rock strength determinations using a Schmidt hammer. Unmanned Aerial Vehicle (UAV) photogrammetry was used to build detailed digital surface models of inselbergs and to recognize geometric patterns of dike arrays. In addition, 34 rock samples were collected to determine rock composition and evaluate their resistance to weathering. The results show that >60 % of dikes display a sub-horizontal array composed of low- and medium-angle dikes (up to 45° dip), which tend to increase rock-mass resistance, providing effective barriers against weathering and vertical fracturing, and are associated with the most prominent, steep-sided residual hills. Besides, dike swarm geometry controls the slope outlines of some inselbergs, which commonly conform to dike attitudes. By contrast, steeply-dipping dikes (>60° dip) promote weathering along the dike-host rock interface and are hypothesized to underlie the plains between the inselbergs. At a small scale, dikes control the occurrence and evolution of minor rock landforms such as weathering pans, solution runnels, overhangs, and split boulders. Our findings show that the resistance of inselbergs to erosion is not homogeneous in the granitic pluton but is controlled by local factors such as dike occurrence and dip.

Impacts of invasive ants on pollination of native plants are similar in invaded and restored plant communities

Ants are amongst the most successful invaders worldwide and can markedly modify invaded communities through biotic interactions. Invasive ants, for example, can compete with native pollinators for resources, act as legitimate pollinators, or disrupt plant-pollinator mutualistic interactions, thereby affecting native plant reproduction. Ecological restoration aims to mitigate the impact of invasive species and restore ecological communities and ecosystem functioning. Here we investigated the combined effects of two invasive ant species, the yellow crazy ant (Anoplolepis gracilipes) and white-footed ant (Technomyrmex albipes), on the pollination and reproduction of native plants in the context of a large-scale plant community restoration experiment. We conducted ant exclusion experiments and pollinator observations to obtain data on plant reproduction and pollination of four plant species. The experiments were conducted across eight granitic inselbergs on the island of Mahé, Seychelles, four of which are undergoing restoration since 2011 and four remained as invaded control sites (unrestored). Our findings indicate that native plants on Seychelles’ inselbergs relied primarily on flying flower visitors for pollination, considering that the contribution of ants to fruit set was generally small and substantially lower than that of flying pollinators. Moreover, while flying pollinators approached flowering plants irrespective of invasive ant presence, the number of probed flowers per visit was reduced, in both restored and unrestored communities. Therefore, native plant reproduction was negatively affected by the presence of invasive ants and this effect was similar in restored and unrestored plant communities. Our research suggests that invasive ants may contribute to changes in plant communities by deterring legitimate pollinators of native plants, an impact that is unlikely to be alleviated through early stages of ecological restoration.

Granitic Inselberg Erosion Controlled by Dike Swarm Array in Semiarid Brazil

Granitic Inselberg Erosion Controlled by Dike Swarm Array in Semiarid Brazil

Impatiens banen and Impatiens etugei (Balsaminaceae), new threatened species from lowland of the Cross-Sanaga Interval, Cameroon

SummaryWe describe two range-restricted new species to science from the genus Impatiens (Balsaminaceae), both threatened, from lowland of the Cross-Sanaga Interval of western Cameroon. The first, Impatiens banen, appears to be restricted to an open seepage microhabitat on granitic inselbergs in the lowland-submontane forest zone of the Ebo Forest in Littoral Region and is provisionally assessed using the 2012 IUCN standard as Vulnerable. Sharing characters with Impatiens burtonii and I. mannii, it differs from both, and appears to be unique in Cameroon inter alia 1) in the bicolored united lateral petals, the upper petals being white, while the lower petals are an intense pink-purple, 2) the hairy, filamentous spur, purple with a white apex, is curved along its length, almost describing a circle. Inselberg-specific species are unusual in Impatiens.The second species, Impatiens etugei, of the I. macroptera aggregate, is restricted to rocks in the Mutel River of the Kom Wum Forest Reserve of North West Region and is assessed as Critically Endangered. Having similarities with I. mackeyana and I. letouzeyi, it differs from other species in the aggregate inter alia by having opposite leaves (vs always alternate), flower exterior white (vs pink or pink-purple), and in the dorsal petal having a pair of lateral projections (vs projections absent).

Granitic inselbergs of Lara (Panafrican Chain, Far-North Cameroon): Assets for the implementation of geotourism in Mountainous region

Granitic inselbergs of Lara (Panafrican Chain, Far-North Cameroon): Assets for the implementation of geotourism in Mountainous region

Distribution and Morphology of the Bedrock Basins Known as Pans in a Granitic Inselberg Landscape

In 2008, Pogue and Katz reported that on granitic exposures in the Cassia City of Rocks, Idaho, the larger pans (shallow flat-floored gnammas or rock basins with overhanging sidewalls) are developed and preserved high in the local relief. They related this aspect of pan distribution to duration of exposure. This working hypothesis is tested by examining pan distribution on granitic inselbergs located on northwestern Eyre Peninsula, in semiarid southern South Australia. Pans in numbers have developed on sensibly level surfaces and have been shaped by pools of standing water. The larger—and more complex—forms are situated high in the local relief, as concluded by Pogue and Katz, but where water supply is limited to direct precipitation, by contrast with lower sites, where rainfall is augmented by runoff.

Four new species of Pleroma (Melastomataceae) from campos rupestres and vegetation on granitic inselbergs in Eastern Minas Gerais, Brazil

Eastern Minas Gerais has been historically neglected regarding biodiversity sampling effort. However, recent botanical explorations have revealed several new taxa for its flora, especially from disjunct fragments of campos rupestres vegetation, which form a mosaic with granitic inselbergs in the region. In this article, we add four new species of Pleroma (Melastomataceae) to the growing list of new taxa: P. brevicomosum, P. caetanoi, P. miconiifolium and P. petrophylax. We provide descriptions, detailed photographs, taxonomic comparisons, a distribution map and conservation status assessments for these new taxa. All four species are assessed under a category of threat, highlighting the need for conservation actions in these biodiverse albeit still poorly known areas.

Seed dispersal by frugivores from forest remnants promotes the regeneration of adjacent invaded forests in an oceanic island

Forest remnants often act as refuges for native plant species within a degraded and highly fragmented forest matrix. Understanding whether these native patches can function as feeding grounds for frugivores and seed sources for native plant dispersal into the surrounding forest can provide critical information on ecosystem functions on a landscape scale and guidance on forest restoration. We used a large‐scale natural system of eight granitic inselbergs in the Seychelles and recorded the identity and transport direction of seeds retrieved from the droppings of mist‐netted birds across an invasion gradient. We found that inselberg forest remnants are important feeding areas for frugivores, acting as a source of native propagules to the surrounding invaded forests and potentially limiting the progression of non‐native plant invasion. Two dominant non‐native plant species (Cinnamomum verum and Clidemia hirta) were highly integrated into the frugivores' diets, competing with native plants for dispersal services. Despite the high non‐native propagule pressure, the spill‐over effect of native seeds into the invaded forest seemed to have a more durable positive effect on native plant recruitment fading out with distance to the inselberg edge. Our findings illustrate that remnant forest patches can generate positive spill‐over of native seeds into degraded surrounding forests through directed seed transport by frugivores. This cross‐boundary transport may slow down plant invasion and contribute to the recovery of adjacent degraded ecosystems. Forest remnants and avian frugivores therefore play a key role in the maintenance of native biodiversity and act as insurance for future restoration efforts.

Flora of Espírito Santo: Droseraceae

Abstract We present a taxonomic treatment of the species of Droseraceae in Espírito Santo state, Brazil. Droseraceae is represented in the state by two species: Drosera intermedia, found in marshlands in the restingas (pioneer formations), and Drosera latifolia, which occurs in the campos de altitude (ecological refuges) and on granitic inselbergs in areas of ombrophilous forest in the mountainous region of Espírito Santo. We provide an identification key, morphological descriptions, and commentaries on taxonomy, ecology, conservation, and geographical distribution.

Maracujá on the rocks: a new Passiflora species (Passifloraceae sensu stricto) from the rupicolous ecosystems of the Brazilian Atlantic rainforest

Here we describe a new species of Passiflora subg. Passiflora (Passifloraceae sensu stricto) found in the Brazilian Atlantic rainforest in areas of campos rupestres of the João Pinto formation in Minas Gerais and on granitic inselbergs of Espírito Santo. The new species, named Passiflora ita, is described, illustrated, compared to similar species and its conservation status is preliminarily assessed as Endangered (EN) following IUCN Red List categories and criteria, reinforcing the importance of the areas where it occurs (which are not national or state-level parks) as priorities for conservation. Citation: Mezzonato-Pires A. C., Ribeiro R. da S. & Gonella P. M. 2021: Maracujá on the rocks: a new Passiflora species (Passifloraceae sensu stricto) from the rupicolous ecosystems of the Brazilian Atlantic rainforest. – Willdenowia 51: 371–381.https://doi.org/10.3372/wi.51.51305 Version of record first published online on 14 December 2021 ahead of inclusion in December 2021 issue.

Guidelines for Management of Geoheritage: an Approach in the Sertão Central, Brazilian Northeastern Semiarid

The characterisation of geoheritage and the understanding of the physical and socio-cultural features of a territory are essential to achieve the major geoconservation goals: protection and sustainable use of exceptional elements of geodiversity. This research was done in the Sertao Central, an economic vulnerable area in the hinterland of northeast Brazil, remarked by the Caatinga Biome and a rocky, semiarid landscape. The area comprises an assemblage of deformed igneous and metamorphic rocks, such as gneisses, TTG rocks, schists, and granites. Starting from a regional geoheritage inventory done in 2015, fourteen geosites were selected and assessed, representing a wide regional tectonic evolution from the Precambrian West Gondwanan orogenesis to the Cenozoic development of particular examples of Brazilian granitic inselbergs. In addition to the inventory of geosites, six geodiversity sites were also evaluated, along with five geocultural sites, highlighting the cultural value of geodiversity in the area. Based on the available information, an analysis with the main features and spatial configuration of the geoheritage was developed, allowing to designate the most appropriate use for each geological site. Considering geoconservation as a geoscientific fostering for the sustainable development, our study suggests a set of general guidelines for the management of geoheritage, in order to facilitate the decision-making process by local managers and stakeholders as well as to promote the discussion on geotourism strategies for the region. Organised according to well-defined geoconservation strategies, these guidelines could enhance the sustainable development of vulnerable regions, such as Sertao Central itself.

Modelling the impact of canker disease and fire regimes on the population dynamics and extinction risk of the Critically Endangered and granite endemic shrub

Landscape-level processes such as fire regimes, increasing disease prevalence and a drying climate are emerging threats affecting plant groups such as the Proteaceae. Using field derived empirical data and a population simulation model we investigated population-level impacts of canker diseases and contemporary fire regimes on the threatened shrub and granite outcrop endemic Banksia verticillata R.Br. We found the persistence of B. verticillata on granite inselbergs is strongly influenced by fire frequency and extent, as well as the prevalence of canker disease. For populations where canker is present but having a relatively lower impact none of the fire scenarios resulted in extinction over the 100-year simulation, but all scenarios resulted in population decline with the magnitude of the effect increasing with fire frequency and extent (proportion of plants killed). In contrast, higher impact canker disease scenarios resulted in rapid population declines and potential extinction. Small increases in inter-fire adult survival reduced the rate of decline in populations with relatively low canker infestation. Research is urgently needed to understand the role that a warming and drying climate in the South-west Australian Floristic Region may have on the epidemiology of canker disease and the feasibility and effectiveness of treating individuals with appropriate fungicides.

Contemporary distribution of Macrozamia dyeri (Zamiaceae) is correlated with patterns of Nyungar occupation in south‐east coastal Western Australia

AbstractIndigenous societies’ interactions with plants may result in contemporary distribution patterns that reflect these relationships, such as concentration of resource species close to occupation sites or transport routes. Seeds of the cycad, Macrozamia dyeri, are food of Nyungar First People of the south‐eastern Southwest Australian Floristic Region. Processing of seeds by leaching in soil or water enables detoxification and preservation of the pre‐colonial staple, a Nyungar technique archaeologically dated to at least 13 000 years BP. We measured the distance of M. dyeri populations to cultural landscape features and registered heritage sites. We also compared within‐population plant distribution characteristics to Nyungar occupation preferences around granite inselbergs. We found evidence of Nyungar influence on contemporary distribution of M. dyeri. Populations of M. dyeri occur close to surface water features in the west and granite outcrops in the east of Nyungar country, which corresponds closely to differential pre‐colonial patterns of Nyungar occupation. M. dyeri population frequency was negatively correlated with distance to registered Nyungar sites, and 75% of all M. dyeri populations occur within 3.2 km of a registered Nyungar site. We found no correlation between habitat availability and size of granite populations, but found that Nyungar occupation preferences in relation to ground surface aspect, slope and landform type correlated with intra‐population M. dyeri plant distribution, suggesting a mutualistic relationship with Nyungar people, has influenced the plant’s distribution. We suggest that contemporary M. dyeri distribution is therefore useful for interpreting past location‐specific Nyungar land practices to inform contemporary conservation management. Our findings demonstrate that along with edaphic, climate and other environmental factors, consideration of pre‐colonial human dispersal and land practices is important for plant conservation in Australia, particularly for taxa with prolonged use by humans. Further, we suggest that analyses of long‐lived Macrozamia elsewhere may be useful for interpreting past Aboriginal land practices.

High species diversity and turnover in granite inselberg floras highlight the need for a conservation strategy protecting many outcrops.

Determining patterns of plant diversity on granite inselbergs is an important task for conservation biogeography due to mounting threats. However, beyond the tropics there are relatively few quantitative studies of floristic diversity, or consideration of these patterns and their environmental, biogeographic, and historical correlates for conservation. We sought to contribute broader understanding of global patterns of species diversity on granite inselbergs and inform biodiversity conservation in the globally significant Southwest Australian Floristic Region (SWAFR). We surveyed floristics from 16 inselbergs (478 plots) across the climate gradient of the SWAFR stratified into three major habitats on each outcrop. We recorded 1,060 species from 92 families. At the plot level, local soil and topographic variables affecting aridity were correlated with species richness in herbaceous (HO) and woody vegetation (WO) of soil‐filled depressions, but not in woody vegetation on deeper soils at the base of outcrops (WOB). At the outcrop level, bioclimatic variables affecting aridity were correlated with species richness in two habitats (WO and WOB) but, contrary to predictions from island biogeography, were not correlated with inselberg area and isolation in any of the three habitats. Species turnover in each of the three habitats was also influenced by aridity, being correlated with bioclimatic variables and with interplot geographic distance, and for HO and WO habitats with local site variables. At the outcrop level, species replacement was the dominant component of species turnover in each of the three habitats, consistent with expectations for long‐term stable landscapes. Our results therefore highlight high species diversity and turnover associated with granite outcrop flora. Hence, effective conservation strategies will need to focus on protecting multiple inselbergs across the entire climate gradient of the region.

Linear and geometric morphometrics as tools to resolve species circumscription in the Pseudolaelia vellozicola complex (Orchidaceae, Laeliinae)

Background and aims – Pseudolaelia is a genus endemic to eastern Brazil, with 12 accepted species predominantly distributed across granitic inselbergs of the Brazilian Atlantic Forest. The aim of the present study was to distinguish between the very similar taxa P. aguadocensis, P. oliveirana, P. regentii and P. vellozicola, using morphometric data acquired as linear measurements and outlines capture with Elliptic Fourier Analysis (EFA) of the floral parts. Material and methods – We sampled 208 specimens from 11 natural populations of the above taxa. We measured 20 floral variables and for the EFA, and we extracted 24 shape variables from the Fourier coefficient matrices, which describe the outlines of the floral parts. In both cases the data were analyzed with multivariate methods (both ordination and clustering). Key results – We could not find morphological discontinuities with sufficient magnitude to consider P. aguadocensis, P. oliveirana and P. regentii as distinct species from P. vellozicola. Conclusions – We propose that P. vellozicola should be considered a polymorphic and widely distributed species, generally supported by both methods.