Subtropical Highland Grasslands Research Articles

Unravelling the genetic diversity and taxonomic ambiguities of endemic Petunia species from subtropical highland grasslands

Abstract Closely related and young species often show high morphological similarity, challenging their identification and correct assignment. Molecular markers and integrative approaches have contributed to solving many taxonomic uncertainties. In this study, we evaluated the genetic variability and ecological features of Petunia guarapuavensis and Petunia scheideana, over which there is a taxonomic debate. Both species are endemic and rare, distributed in the subtropical highland grasslands in southern South America. We based our analyses on nuclear microsatellite and plastid sequences, aiming to disentangle the taxonomic ambiguities that made some consider these entities synonymous despite occupying different clades in the genus phylogenetic tree. Our findings support that there is genetic differentiation between these species, suggesting that they are independent taxonomic entities despite sharing floral traits and a few molecular polymorphisms. The low genetic sharing between the species is likely due to a common ancestor and recent divergence time. In contrast, their morphological similarity can be attributed to the absence of selective pressure, as both grow under similar ecological conditions. This study emphasizes that adding more than one sequence per species, combining data with dissimilar inheritance patterns, and exploring data through different methodologies help to disentangle taxonomic incongruences and reveal diversity that might otherwise remain hidden.

Green, charismatic, microendemic, and threatened: breeding biology of the leaf frog Pithecopus rusticus (Anura: Hylidae: Phyllomedusinae)

ABSTRACT Pithecopus rusticus is a small and charismatic leaf frog species known only from the type locality, in the Brazilian Subtropical Highland Grasslands of the Atlantic Forest, southern Brazil. In this study, we describe aspects of the reproductive biology and populational size of P. rusticus, encompassing the characterization of breeding season, microhabitat use for vocalization and spawning, the variation in body size of males and females and operational sex ratio, as well as explore the influence of climate variables on the abundance of individuals. We collected information from 2015 to 2021, mainly in the breeding seasons of 2015/16 and 2017/18. We recorded 91 individuals of P. rusticus, with a recapture rate of 61% in the 2015/16 breeding season and 57% in the 2017/18 breeding season. The estimated population size was 28.9 individuals for the 2015/16 breeding season and 21 individuals for the 2017/18 breeding season. The temporal reproductive pattern was intermediate, being concentrated in spring to early summer months (October to January), and the male calling activity differed throughout the night, increasing from 9pm onwards. The abundance of P. rusticus was significantly related with relative air humidity. We found sexual size dimorphism, with females larger than males, and a male-skewed operational sex ratio. Males and females used Poaceae and Cyperaceae leaves located close to water. Spawns contained 43 ± 5 eggs, with a diameter of 3.26 ± 0.45 mm, and were deposited on leaves of Senecio (Asteraceae) and Eriocaulon (Eriocaulaceae). Information on natural history is essential to support the implementation and success of in situ and ex situ conservation strategies for this endangered species.

Land-use effects on aquatic macroinvertebrate diversity in subtropical highland grasslands streams

Knowledge of the frequency and occurrence of macroinvertebrates throughout landscapes may clarify the effects of anthropic impacts on aquatic systems and help guide conservation actions for watersheds. We evaluated macroinvertebrate α and β diversity in streams in four different subtropical phytophysiognomies: highland grasslands with arboreal riparian vegetation, highland grasslands without arboreal riparian vegetation, mixed ombrophilous forest and silviculture. We also evaluated how environmental factors influence α diversity. We sampled macroinvertebrate communities (by Surber sampler), litter input (by nets) and physicochemical variables of the water (by multiparameter and chemical analysis) at 10 sites in riparian zones of a highland system. A total of 2124 individuals were sampled representing 41 taxa, with high α and β diversity in mixed ombrophilous forest. The results indicate that environmental heterogeneity increases food resource availability, as well as macroinvertebrate diversity. Furthermore, the β diversity was found to increase with distance among the unconnected streams. Areas of silviculture had the highest density values among the sampled areas due high organic material stock in the soil. Therefore, higher leaf litter input may decrease the toxicity effect of secondary compounds released by leaf plant decomposition compared to environments with low systemic leaf litter input, such as highland grasslands. The presence of arboreal riparian vegetation drives canopy openness, water temperature, dissolved oxygen, and orthophosphate in streams, which control the frequency and occurrence of benthic macroinvertebrates. Homogeneous systems, as naturally observed in highland grasslands, plus high canopy openness decrease macroinvertebrate richness and density. The naturally low richness of highland grasslands, although with endemic species, may be an important guideline for legislation on anthropic impacts, management, and conservation of streams in this specific subtropical zone.

Past climate changes and geographical barriers: the evolutionary history of a subtropical highland grassland species of Solanaceae,Petunia altiplana

AbstractClimate changes and associated glacial and interglacial cycles during the Quaternary strongly influenced the evolutionary history of countless number of species. Subtropical highland grasslands (SHG) in southern South America constitute a distinct vegetation type with high diversity and endemism rates. The most recent common ancestor of the genus Petunia (Solanaceae) originated in lowland grasslands, and some lineages secondarily migrated to SHG. Here, we describe the evolutionary history of an SHG species, P. altiplana, distributed throughout a wide area in a river-fragmented landscape. We used plastid and nuclear markers to evaluate the role of the Pelotas River and Quaternary climate cycles over the genetic structure and historical demography of this species based on a phylogeographical approach. We found moderate population expansions during the last 25 kyr, with a more recent (c. 1.6 kya) divergence between two groups of populations from opposite river margins, possibly caused by the expansion of the Araucaria Forest along the river valley, effectively isolating distinct grassland patches.

Disentangling the causes of high polymorphism sharing in sympatric Petunia species from subtropical highland grasslands: insights from nuclear diversity.

Genetic polymorphism sharing between closely related and sympatric plant species could result from common ancestry, ancient or recent hybridization. Here we analyzed four Petunia species from the subtropical highland grasslands in southern South America based on nuclear diversity to disentangle the causes of high polymorphism sharing between them. We genotyped microsatellite loci, employed population genetic methods to estimate variability, species limits, and ancient and recent gene flow, and assigned individuals to genetic and taxonomic groups. Finally, we modeled evolutionary processes to determine the impact of Quaternary climate changes on species phylogenetic relationships. Our results indicated that genetic diversity was strongly influenced by expansion and habitat fragmentation during the Quaternary cycles. The extensive polymorphism sharing is mainly due to species' common ancestry, and we did not discard ancient hybridization. Nowadays, niche differentiation is the primary driver for maintaining genetic and morphological limits between the four analysed Petunia species and there is no recent gene flow between them.

Ericaceae in Rio Grande do Sul state, Southern Brazil

This study presents a taxonomic review of the native species of Ericaceae in Rio Grande do Sul state, Southern Brazil, providing identification keys, synonymy, morphological descriptions, and specimen photograph plates, besides maps of geographic distributions and lists of studied specimens to assist in identification and conservation. We made literature reviews, collecting expeditions, and reviewed 14 Brazilian herbaria, plus an additional 17 online herbaria. We confirmed the occurrence of three genera, 10 species, and 11 taxa, including the new occurrence of Gaultheria ulei to the state. All species occur in the Brazilian subtropical highland grasslands of the Atlantic Rainforest. Five species were confirmed occurring in the temperate grasslands of the Pampas, where Agarista eucalyptoides and A. chlorantha were previously known and A. minensis, A. nummularia and Gaylussacia brasiliensis represent new records. Agarista eucalyptoides and Gaylussacia brasiliensis are the most widely distributed species in the state. Agarista nummularia and Gaylussacia brasiliensis are the only species registered in the coastal plains. Five species are threatened in the state flora: Agarista chlorantha (EN), A. minensis (VU), A. niederleinii (VU), Gaultheria itatiaiae (EN), and Gaylussacia pseudogaultheria (EN). Additionally, we highlight seed shape as a distinctive trait to separate species within Agarista.

Landscape genetics reveal low diversity and adaptive divergence inPortulaca hatschbachii(Portulacaceae): an endangered species endemic to rocky outcrops of the Atlantic Forest

AbstractPortulaca hatschbachii is endemic to the basaltic rocky outcrops that are distributed, in a discontinuous way, along the Third Plateau of Paraná State, Brazil, composing environments that form the Subtropical Highland Grasslands of the Atlantic Forest Biome. Considering the risk of extinction of the species and the massive anthropization of these outcrops, we applied AFLP, ITS and rps16 molecular markers in ten populations throughout the area of occurrence of the species to generate information about the genetic status of P. hatschbachii and contribute to the development of conservation strategies. Low rates of genetic diversity, high population structure, restricted gene flow and the presence of diversifying selection were observed for the populations. The analysis of variation partitioning (R2adj. = 63.60%) showed that environmental variables have a greater influence on the distribution of variation of loci under selection (R2adj. = 26.70%) than geographical isolation (R2adj. = 1.20%). The strong population structure, for both neutral and selected loci, suggests an isolation by adaptation mechanism (IBA) occurring in populations and highlights the need and urgency for in situ conservation plans for the species and its occurrence on rocky outcrops.

Genetic diversity in micro-endemic plants from highland grasslands in southern Brazil

AbstractPopulation genetic structure results from the interaction between historical events, current ecological conditions and life traits. The genetic structure and gene flow between populations are important to species dynamics, mainly for rare and endangered species that are more vulnerable to landscape changes and fragmentation. Here we evaluated the genetic diversity, population structure and gene exchange in Petunia bonjardinensis, P. reitzii and P. saxicola, three rare species endemic to subtropical highland grasslands in southern South America. We analysed the genetic diversity and structure considering historical events, such as founder effect and climate changes, and biological traits of each species. We also estimated the conservation status for these three species. We collected samples from all adult individuals and occurrence sites that could be found at the same flowering season and genotyped them for 13 nuclear microsatellite markers. Our results indicate that rarity is probably historical for these species, given that we found no genetic evidence for recent bottlenecks. Petunia bonjardinensis, with the largest occurrence area and population sizes, displayed the higher diversity indices. The other two showed lower genetic diversity and are geographically most restricted. Gene exchange among these species was low, although they share some ancestral genetic polymorphism. Historical migration, founder effects and Pleistocene climate cycles ae the main factors explaining genetic diversity, and this was also influenced by reproductive biology and recent habitat loss, whereas the landscape influences the structure. Based on IUCN criteria, the three species are endangered, and the main risk for their survival is probably anthropic activity in the occurrence area. We recommend an urgent programme for the preservation of these species in situ and ex situ.

Grazing intensity drives plant diversity but does not affect forage production in a natural grassland dominated by the tussock-forming grass Andropogon lateralis Nees

Andropogon lateralis is a tall and highly plastic tussock-forming grass native from southern South America. It is a frequent component of Campos and Subtropical highland grasslands that often becomes dominant under lax grazing regimes. The aim of this work was to analyze the response of species diversity and forage production of a natural grassland dominated by A. lateralis to a wide range of grazing intensity. We hypothesized that species diversity and forage production would both peak at the intermediate canopy heights determined by grazing regimes of moderate intensity. A grazing experiment was conducted in a highland grassland with mesothermal humid climate at 922 masl (Atlantic Forest biome, Santa Catarina state, Brazil) that comprised 87 species from 20 families but had 50% of its standing biomass accounted by A. lateralis. Four pre-/post-grazing canopy heights—12/7, 20/12, 28/17, and 36/22 cm (measured on A. lateralis)—were arranged in a complete randomized block design with four replications, and intermittently stocked with beef heifers from October 2015 to October 2017. Andropogon lateralis cover decreased (from 75 to 50%), and species richness increased (15–25 species m−2) as canopy height decreased. Grazing intensity did not affect annual forage production (4.2 Mg DM ha−1). This natural grassland dominated by A. lateralis had a high capacity to adjust to grazing regimes of contrasting intensity, maintaining forage production stable over a wide range of canopy heights. However, to prevent losses in floristic diversity, such grassland should not be grazed at canopy heights higher than 28 cm.

<p><strong>The importance of the Brazilian Subtropical Highland Grasslands evidenced by a taxonomically verified endemic species list. <em>Phytotaxa </em>452 (4): 250-267</strong><strong> (ERRATUM)</strong></p>

ERRATUM

<p><strong>The importance of the Brazilian Subtropical Highland Grasslands evidenced by a taxonomically verified endemic species list</strong></p>

The Brazilian Subtropical Highland Grasslands (Campos de Cima da Serra) is one of the main areas of endemism in southern Brazil. The complex biogeographic history that resulted in the floristic composition of the region is directly linked to the high degree of plant endemism found there. Here we present a current checklist for the endemic plants – the first taxonomically verified endemic species list for the region. The list comprises 273 endemic taxa (23.5% of its flora) representing 40 families and 117 genera, highlighting fifty-seven taxa reported as endemic from the region for the first time in recent years. Voucher specimens, original publication, locality information and distribution data are provided for each endemic taxon. Botanical collections in the Brazilian Subtropical Highland Grasslands have increased exponentially during the last four decades. However, 41 taxa are known only from the original collection record reported in their protologue. Our results emphasize the importance of the Brazilian Subtropical Highland Grasslands in terms of conservation of its flora and the importance of providing complete information on botanical collection labels as source for a robust knowledge of the flora.

Distribution and conservation status of Drosera viridis Rivadavia (Droseraceae), including the first records from Rio Grande do Sul, Brazil, and a key to the genus in this state

Drosera viridis Rivadavia, a Brazilian endemic species of carnivorous herb, has its geographical range extended in South Brazil, including the first records for Rio Grande do Sul, from subtropical highland grasslands in the northeastern region of the state. Taxonomic notes, habitat information, an updated distribution range, and an identification key for the Drosera L. species from Rio Grande do Sul are presented. Based on the updated distributional range and potential threats in Brazil, we suggest the species to be classified as Near Threatened, following IUCN Red List categories and criteria.

Distribution and conservation status of Drosera viridis Rivadavia (Droseraceae), including the first records from Rio Grande do Sul, Brazil, and a key to the genus in this state

Drosera viridis Rivadavia, a Brazilian endemic species of carnivorous herb, has its geographical range extended in South Brazil, including the first records for Rio Grande do Sul, from subtropical highland grasslands in the northeastern region of the state. Taxonomic notes, habitat information, an updated distribution range, and an identification key for the Drosera L. species from Rio Grande do Sul are presented. Based on the updated distributional range and potential threats in Brazil, we suggest the species to be classified as Near Threatened, following IUCN Red List categories and criteria.

Valeriana caparaoensis (Valerianaceae nom. conserv.), a New Species from Southeastern Brazil

Abstract—Valeriana caparaoensis, a new species from the High Altitude Tropical Grasslands of Southeastern Brazil, is described and illustrated. The new species is known only from the Serra do Caparaó massif, between the states of Minas Gerais and Espírito Santo, Southeastern Brazil. It shares morphological affinities with V. catharinensis and V. polystachya, the first restricted to Brazilian Subtropical Highland Grasslands, and the last restricted to Lowland Grasslands of Southern Brazil, Uruguay and Argentina. Besides the great geographical disjunction, the new species differs from the other two species by the pinnately lobed proximal leaves, by the lanceolate distal lobes and longer pseudopetioles in distal leaves, by differences in the size of the flowers, and by the rounded to ovate and broader achenes. Additionally, we provide the preliminary conservation status assessments using IUCN Red List categories and criteria, as well as an updated checklist and a key for Valeriana species from Southeastern Brazil.

Restoration of abandoned subtropical highland grasslands in Brazil: mowing produces fast effects, but hay transfer does not

Subtropical Campos Sulinos grasslands, in South Brazil, are among the most biodiverse grasslands of the world. As climatic conditions lead to high productivity, disturbance are critical to maintain their diversity. Long-term exclusion, on the other hand, leads to plant species losses and changes in composition. No studies on the restoration of these grasslands after abandonment exist to date. We tested combinations of restoration techniques with the aim of increasing plant diversity in an abandoned and species-poor grassland in the South Brazilian highland region. In a bi-factorial experiment, we tested the effects of two different frequencies of mowing and of hay transfer. Mowing reduced plant cover, vegetation height, and abundance of erect grasses and shrubs, and increased species richness, diversity (Shannon diversity index) and prostrate forb and grass cover. No differences were found between mowing frequencies. Hay transfer was not effective at reintroducing species. The results of the present study provide further evidence that the reintroduction of plants is a major challenge in the restoration of subtropical and tropical grasslands. The study shows that mowing is a fast way to increase plant diversity in Campos Sulinos after long periods of abandonment.

Endemic plants from the Southern Brazilian Highland Grasslands

Abstract The flora of the subtropical highland grasslands in Southern Brazil, locally known as Campos de Cima da Serra, is within the Atlantic Forest hotspot, and has being highlighted by its richness, having around 25% of endemic plants. Those formations require specific studies to estimate its species richness and to protect its natural resources. This study aimed to map and to analyze the distribution of endemic taxa from these grasslands based on available herbarium collections databases as sources for highlighting important taxonomic groups for future studies. We verified how much of those endemic taxa are inside protected areas, and recognized the most important taxa and areas for future studies. All the data about each endemic taxon was obtained through visiting herbaria, online databases, collecting expeditions and published references. Distribution maps for endemic species were prepared. As the main result, we describe and map the distribution of the endemic flora of this species rich vegetation formation and highlight the threatened taxa as priority for future taxonomic and conservation studies. Our results also point out the central-west of Santa Catarina and central Paraná states as priority areas for future studies considering its high diversity of taxa.

Genetic and ecological niche modeling of Calydorea crocoides (Iridaceae): an endemic species of Subtropical Highland Grasslands.

Evolutionary analyses have been widely used for evaluation of genetic diversity of natural populations and correlate these data to the fitness of the species, especially in the case of threatened species. Calydorea crocoides occurs in a restricted area at altitudes from 800 to 1500 m in southern Brazil and is considered endangered. A study assessing genetic diversity, cytogenetic features and ecological niche was performed aiming to characterize C. crocoides by multidisciplinary approaches. Molecular data highlighted that most of the total variation (76%; p < 0.001) was found within populations and the parameters of genetic diversity were high at the species level (PPB = 98.97%; I = 0.4319; h = 0.2821). Gene flow (Nm) was estimated in 0.97 individuals per generation. Cytogenetically, C. crocoides presents a bimodal karyotype and low asymmetry. DAPI banding pattern was uniform, but the CMA-signal evidenced a pericentric inversion in the population ESC688. The species presents high pollen viability and two different morphologies of pollen grains. Our data showed high levels of polymorphism maintained in this species that could ensure conservationist practices in which the main goal is to preserve the evolutionary potential of the species through the maintenance of genetic diversity.

Plant distribution in freshwater wetlands of the Brazilian subtropical highland grasslands

Wetlands are heterogeneous environments that harbor several species. In spite of playing a key role in aquatic ecosystems, macrophytes are the most neglected group in limnological studies. In the Brazilian subtropical highland grasslands, freshwater wetlands occur intermingled with native grasslands. Our objective was to assess species richness and variation in floristic composition along transects. We sampled 324 units to compare floristic similarity between and within areas based on non-metric multidimensional scaling (NMDS). We recorded plants of 40 families, 88 genera, and 133 species, out of which 17 are endangered. The richest families were Poaceae, Cyperaceae, and Asteraceae. The life forms found included amphibious, emergent, and fixed submerged types. The NMDS pointed to dissimilarity between and within areas. We observed the formation of two zones. In the outer zone, we detected seven indicator species and 17 exclusive species. In the inner zone, we detected five indicator species and 29 exclusive species. Our study suggests that wetlands are species-rich, heterogeneous environments characterized by different zones. The knowledge of biodiversity and presence of indicator species is key to the elaboration of strategies for the restoration and conservation of freshwater wetlands.

Environmental drivers of diversity in Subtropical Highland Grasslands

The aim of this study was to identify major bioclimatic variables associated with the diversity patterns of plant genera and the contribution of elevations in highly diverse areas of the Subtropical Highland Grasslands (SHG), which form mosaics with Araucaria forests. We selected three plant genera that have diversified, in part, within the Neotropical SHG: Adesmia (Fabaceae) and Calibrachoa and Petunia (Solanaceae). We delimited the major high elevation areas of the region and calculated the taxonomic diversity for these taxa in each area. Ecological Niche Models (ENMs) were used to predict the distribution of each taxon and to project it to the Last Glacial Maximum (LGM), allowing searching for stable areas. Those stable areas were then compared to areas with high diversity levels. We explored the spatial occurrences and the multivariate contribution of environmental factors to differentiate among the Araucaria forest and the SHG. Finally, we examined the correlations between the environmental variables and the molecular and taxonomic diversity. Niche stability was directly linked to diversity and positively correlated with altitude. Although some niche aspects differed subtly, the predicted distributions of grassland and forest taxa were not different at larger scales. Two of the four studied areas were suggested by the ENMs to be high-relevant sites for conservation studies and the maintenance of diversity.

Baccharis napaea (Asteraceae, Astereae): a new species of subgen. Tarchonanthoides sect. Coridifoliae from the subtropical highlands of southern Brazil

Baccharis napaea, a new species belonging to subgen. Tarchonanthoides sect. Coridifoliae is described and illustrated. The new species is compared to and distinguished from the sympatric species B. coridifolia, B. erigeroides, and B. scabrifolia, and from the allopatric B. bicolor. Baccharis napaea occurs in open subtropical highland grasslands and the edges and open glades of subtropical mixed forests on the south Brazilian plateau. Additionally, a distribution map and description of habitat and conservation status of the new species are presented.