Highland Grasslands Research Articles

How many species are there? Lineage diversification and hidden speciation in Solanaceae from highland grasslands in southern South America.

Species delimitation can be challenging when analysing recently diverged species, especially those taxonomically synonymised due to morphological similarities. We aimed to untangle the relationships between two grassland species, Petunia guarapuavensis and Petunia scheideana, exploring the dynamics of fast divergence and addressing their species delimitation. We used a low-coverage genome sequencing and population genomic approach to distinguish species and populations between P. guarapuavensis and P. scheideana. Our analysis focused on detecting structuration, hybridisation/introgression, and phylogenetic patterns. We employed demographic models to support species delimitation while exploring potential phylogeographic barriers influencing gene flow. Our findings indicated differentiation between the two species and revealed another lineage, which was phylogenetically distinct from the others and had no evidence of gene flow with them. The presence of a river acted as a phylogeographic barrier, limiting gene flow and allowing for structuration between closely related lineages. The optimal species delimitation scenario involved secondary contact between well-established lineages. The rapid divergence observed in these Petunia species explains the lack of significant morphological differences, as floral diagnostic traits in species sharing the pollinators tend to evolve more slowly. This study highlights the complexity of species delimitation in recently diverged groups and emphasises the importance of genomic approaches in understanding evolutionary relationships and speciation dynamics.

Effects of riparian forest and annual variation in stream environmental conditions on leaf litter breakdown and invertebrate communities in highland grassland streams

Effects of riparian forest and annual variation in stream environmental conditions on leaf litter breakdown and invertebrate communities in highland grassland streams

Leaf quality and macrofauna are more important than the presence of trees and shrubs in riparian vegetation for leaf litter breakdown in subtropical highland grassland soil systems

Leaf quality and macrofauna are more important than the presence of trees and shrubs in riparian vegetation for leaf litter breakdown in subtropical highland grassland soil systems

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.

The phylogeographic journey of a plant species from lowland to highlands during the Pleistocene

Phylogeographic history refers to how species evolve and diversify in response to historical, ecological, and demographic factors. The climate fluctuation during the Pleistocene period marked a crucial time in shaping many species’ distribution and genetic structure, particularly those from southern South American grasslands. This work investigated the phylogeographic history of a highland grassland, Petunia altiplana T. Ando & Hashim. (Solanaceae), its diversity, and geographic distribution using a population genomic approach based on RAD-seq data. Our results indicated that, during the Pleistocene, when the grasslands expanded to highlands, the lowland populations of P. altiplana reached the higher open fields, enlarging their geographic distribution. We found that the P. altiplana genetic diversity followed the geographic division into eastern (E) and western (WE) population groups, with a subtle division in the E group regarding the Pelotas River headwater. The results also showed that isolation by distance was the main divergence pattern, with elevation playing a pivotal role in shaping WE and E groups. Our findings indicated that lowland-adapted populations quickly colonized highlands during the late Pleistocene.

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.

Checklist preliminar de libélulas (Insecta: Odonata) do Estado de Santa Catarina, Brasil

Abstract In this study, we provide a checklist of the species of Odonata (Insecta) from the state of Santa Catarina (southern Brazil), along with their location records in the municipalities across the state (whenever possible). We compiled 147 species from 60 genera and nine families, making Santa Catarina the second state with the most Odonata species recorded in southern Brazil. The families with the highest number of species were Libellulidae (54 species from 18 genera), followed by Coenagrionidae (36 species from 17 genera), Gomphidae (20 species from ten genera) and Aeshnidae (15 species from eight genera). Several regions of Santa Catarina are unexplored (mostly the westernmost and central regions of the state), whereas the knowledge in the southern coast and the subtropical highland grasslands remains restricted to sparse occurrence records. Moreover, the distribution records in the state show an enormous historical track associated with the establishment of late entomologists in the region. Our study highlights the role of Atlantic Forest biome in maintaining high levels of diversity of Odonata species richness in Brazil and also shows that many areas in subtropical forests in Brazil are not adequately sampled.

Impact of grassland storage balance management policies on ecological vulnerability: Evidence from ecological vulnerability assessments in the Selinco region of China

The Selinco region is a highland grassland ecosystem with a unique lake system and diverse flora and fauna. However, it is highly vulnerable to degradation due to its high altitude and harsh climate. In recent years, the region has been subjected to increasing external pressures, including climate change, human activities, and natural disasters. Therefore, conducting an ecological vulnerability assessment is essential to ensure the sustainable development of the region. To achieve this, we performed a comprehensive integrated spatial principal component analysis (SPCA) of 12 representative ecological vulnerability indicators to assess the ecosystem of the region. This approach facilitated a comprehensive assessment of the ecological status of the region. Our study indicated that population and livestock density are the most important factors influencing environmental vulnerability. While the region has shown a trend of ecological recovery and stability over the past 20 years, some areas still experience ecological deterioration, emphasizing the importance of increasing efforts for to ecological conservation and restoration. Furthermore, we observed that different ecologically fragile areas have experienced varying degrees of transformation, underscoring the importance of more precise ecological conservation policies. At the county level, Nima and Shuanghu counties require focused attention and remedial measures to address severe ecological degradation, while other counties have demonstrated a trend towards ecological restoration, which could be attributed to the implementation of a balanced grass storage management policy that mitigates the impact of human activities. Therefore, further research is essential to determine the persistence of ecological trends and to identify long-term conservation and sustainable use solutions.

A review of Madagascar's derived grasslands: Low palatability following anthropogenic fires may threaten food security

Societal Impact StatementThe 26th United Nations Climate Change Conference emphasised the need to modify practices that negatively impact biodiversity and food security in the context of global change. Following Madagascar's drought‐induced famine, our systematic review supports the theory that grasslands of the Malagasy Central Highland that are subjected to human‐lit fires are anthropogenically derived. Furthermore, these overly frequent fires that characterise much of the Malagasy Central Highland grasslands select poorly palatable grasses. Given the reliance on pastoralism as insurance against crop failure in Madagascar, fire‐dependent practices that degrade rangeland emerge as a threat to food security and biodiversity. Education can mitigate against future humanitarian crises.SummaryFood insecurity is greatest in countries where impacts of global change are predicted to be severe. Many, like Madagascar, rely on livestock‐based pastoralism (and consequently palatable rangelands) for insurance against natural disasters and crop failure. It is recognised that derived grasslands can impact climate and biodiversity. Furthermore, the well‐established palatability‐flammability trade‐off predicts that overly‐frequent fires select increasingly unpalatable, fire‐adapted grassland. The drought‐induced Malagasy famine of 2021 highlights the need to identify factors that threaten food security. Given the ubiquitous practice of rangeland preparation through annual, landscape‐scale human‐lit fires, we evaluate whether Malagasy grasslands are derived and then test for fire‐driven selection of increasingly degraded and unpalatable rangelands across Madagascar's largest grassland system, the Malagasy Central Highland (MCH). We conducted a systematic literature review, evaluating for a palatability‐flammability trade‐off, by determining dominant Malagasy grass species, and then applying functional traits, and palatability ratings to these species. Data were extracted using a suite of relevant search terms, and of 1977 studies identified, 145 were directly relevant to the questions posed. Evidence from the review is compelling for much of the Malagasy highland grassland being derived. Furthermore, Malagasy dominant grass species are fire‐adapted with poor forage‐value, suggesting current burning practices negatively impact both biodiversity and pastoralism. Decreasing rangeland palatability caused by human‐lit fires in a society suffering food insecurity emphasises the need to re‐evaluate pastoralist burning practices. Identifying optimal fire frequencies can avert breaching fire‐induced tipping points to rangeland palatability and the humanitarian crises that may follow.

First records of Hydrocotyle itatiaiensis Brade (Araliaceae) in the state of Paraná, southern Brazil

Despite the existence of important floristic and forest inventories in the Paraná state, the montane and upper montane ecosystems still give rise to new species and new records of plants. Here, we report for the first time in the Paraná state Hydrocotyle itatiaiensis Brade (Araliaceae), a rare and poorly studied species endemic to montane and upper montane rainforests and highland grasslands of the South and Southeast regions of Brazil. The previously known geographic distribution had a 700 km gap between northern São Paulo and southern Santa Catarina states, which is now filled by the present record. We provide photographs from the field, a map of occurrences, a description, and comments on the morphology, taxonomy, and conservation status of the species. Our new records reinforce the conservation importance of these environments and the need for further floristic sur-veys in the region.

A new analytical framework for Maxent species distribution models unveils complex spatiotemporal suitability patterns for two migratory seedeaters (Aves: Sporophila) of conservation concern

Maxent species distribution models (SDMs) for rare, migratory taxa can be hindered by methodological and analytical issues. To overcome these problems, we developed an analytical framework to build SDMs for key stages of the annual lifecycle of the Marsh Seedeater and the Black-bellied Seedeater, two Neotropical grassland bird species of conservation concern. Occurrence data were compiled from multiple sources and ten environmental variables were used as predictors. We built SDMs with different spatial partitions, feature classes, and regularization multipliers, and devised a procedure to select models with high discrimination ability, low overfitting, statistically significant performance metrics, and high biological realism. From a total of 992 SDMs, 22 fully met the selection criteria for both species. These selected SDMs were equally or less overfit than non-selected ones and were mostly trained with the checkerboard 2 and n − 1 jackknife partitions. For each modeling scenario, we projected and interpreted composite models that emphasized areas of both consensus and divergence across individual predictions, rather than choosing a single model from the set of final SDMs. In the breeding season, areas of highest suitability occurred in restricted, disjunct sectors of the Campos and Pampas grasslands for the Marsh Seedeater and the highland grasslands of southern Brazil for the Black-bellied Seedeater. In the winter, high suitability for the Marsh Seedeater occurred in the western and northern Cerrado and the Pantanal, while in the spring migration, high suitability for the Black-bellied Seedeater was mostly concentrated in the southeastern portion of the Cerrado. The restricted breeding distribution of the Black-bellied Seedeater suggests that its conservation status should be reviewed. Both species shift their climatic niches and track their habitats throughout the year, responding to a few topographic, land-use, and climatic variables that represent different niche components. By addressing major modeling issues in a three-step model selection procedure, we were able to project precise and biologically interpretable SDMs with the level of complexity required for each modeling scenario. Our framework is readily replicable and can be used to unravel intricate spatial suitability patterns of organisms whose distribution undergoes temporal shifts throughout the year.

Anthropogenic Disturbance, Not Topographic Dispersal Barriers, Limit Forest and Maintain Madagascar's Derived Savannas

Photo 1. Central Highland grassland (RN7 national road; Isalo district). Levels of grass endemicity in Madagascar are most similar to those of the derived grasslands of the previously forested islands of New Guinea, New Zealand, Japan, and the Mascarenes (Mauritius, Réunion, and Rodrigues). Annual burning of Malagasy treeless grasslands west of the escarpment to support zebu cattle is so intensive that it exposes topsoil and selects a fire-adapted anthropogenic grass assemblage of low palatability, dominated by Loudetia simplex, Schizachyrium sanguineum, and Trachypogon spicatus. This habitat is driven by pastoralism, not topography. Photo credit: Grant Joseph. Photo 2. Critically Endangered Verreaux's sifaka (Propithecus verreauxi) in remnant forest at Zombitse, surrounded by anthropogenic grassland. Zombitse is just one of many areas west of the escarpment harboring closed-canopy forests. Over 90% of vertebrates, being predominately forest-adapted, are limited to such areas across Madagascar, despite the fact that almost 80% of the island not under agriculture is now grassland. This evolutionary anomaly is best explained by treeless grasslands having been historically smaller, or ephemeral. Photo credit: Grant Joseph. Photo 3. Despite sharing common ancestry with African Herpestids that have easily evolved to open habitats [e.g., Cynictis penicillata (a); Suricata suricatta (b)], Malagasy Euplerids [e.g., the Endangered Mungotictis decemlineata (c); the Vulnerable and decreasing Cryptoprocta ferox (d)] are forest-adapted. The same is true of all non-arboreal Malagasy mammal lineages, which have failed to evolve into savanna–grassland specialists, suggesting that open habitats have either not been sufficiently stable or sufficiently vast to promote open-habitat adapted species. Photo credit: Colleen Seymour (a); Grant Joseph (b–d). Photo 4. Aside from the remaining subhumid forest patches on the Central Highlands which share many tree species with eastern lowland forest (thus contradicting the proposal of range-pinning), there are multiple canopied, non-savanna systems west of the escarpment, harboring species dependant on woody vegetation. Examples include deciduous forest, e.g., Kirindy Forest, harboring Coua cristata (a); Zombitse Forest, home to the Endangered Lepilemur hubbardorum (b); Tsingy De Bemaraha Forest sustaining Critically Endangered Propithecus deckenii (c), and Spiny Forest, e.g., Raniala Forest, here providing habitat for the Vulnerable and decreasing Furcifer antimena (d). Photo credit: Grant Joseph. Photo 5. Zebu (Bos taurus indicus) cattle number 7 to 10 million head, and form obligate C4 grazing lawns on Madagascar. There is no evidence to date for any Malagasy obligate grazers, past or present. Treeless grazing lawns now occur where paleoecological evidence supports recent existence of C3 forest and woodland tree species, containing subfossils representing extinct herbivores that included a large component of C3 species in their diets. Transformation of these woodlands and forests to grassland, and extirpation of endemic tree-adapted herbivores occurred coeval with the switch from human gathering and hunting to pastoralism and farming. Photo credit: Grant Joseph. These photographs illustrate the article “Dispersal limitation and fire feedbacks maintain mesic savannas in Madagascar: Comment” by Grant S. Joseph and Colleen L. Seymour published in Ecology. https://doi.org/10.1002/ecy.4045

Fire in highland grasslands in the Atlantic Forest Biome, a burned areas time series analysis and its correlation with the legislation

Fire has been an intrinsic ecological component of the ecosystems, affecting the public, economic, and socio-cultural policies of human-nature interactions. Using fire over grassland vegetation is a traditional practice for livestock in the highland grasslands and has economic and environmental consequences that have not yet been understood. A better description of the spatio-temporal biomass burning patterns is needed to analyze the effects of creation and application in these areas. This study used remote sensing techniques based on Sentinel-2 data and machine learning algorithms to identify burning scars and compare them with a national fire collection database for the highland grasslands in the Atlantic Forest Biome in Brazil. The aim is to evaluate public management tools and legislation evolution during the 35 years of the time series analyzed. The results indicated that 12,285 ha of grasslands were converted to other uses, losing about 24% of their original formation, with 10% occurring after banned this practice in 2008. The burned areas classification using the Random Forest algorithm obtained an AUC = 0.9983. Divergences in the burned area’s extent and frequency were found between the municipality’s authorized license and those classified as burned. On average, only 43% of the burned area in the Parque Estadual do Tainhas and its buffer zone had an environmental permit in the last 5 years. This research’s results provide subsidies for revising and creating public policies and consequently help territorial management.

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.

Mammals of the Tandilia Mountain system, current species inhabiting Pampean highland grasslands

Neotropical temperate grasslands comprise the Pampas ecoregion in Argentina. This region is also the center of agricultural development in Argentina, which has led to a significant simplification and homogenization of the landscape. The Tandilia Mountains, located in the Southeast of the ecoregion, house one of the last remnants of the highland grassland that acts as a refuge for several native species, including both endemic and threatened species. This work aims to present an updated inventory of mammal species that inhabit the highland grassland remnants of the Tandilia Mountains. We used several sources of information to compile the list, including museum collections, citizen science projects (i.e., iNaturalist, EcoRegistros, and Argentinian Network for Monitoring Run Over Fauna), literature, and personal observations. We recorded 40 species of mammals, which include 32 native species and eight exotic species. The richest orders were Rodentia (42.5%), Chiroptera (17.5%), and Carnivora (12.2%). The native mammals found in the Tandilia Mountains represent 44% of the mammal diversity of the Pampas ecoregion, among which there are endemic species of the ecoregion, species whose populations are declining globally, and threatened species. Unfortunately, the presence of protected areas in the system is limited to a few small ones, which highlights the urgency of increasing the number and variety of protected areas. The information presented in this work contributes to the knowledge of biodiversity and the planning of conservation actions for the last remnants of highland grasslands.

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.

Identifying key conservation sites for the reptiles of the Tandilia mountains in Pampas highlands

Reptile populations are facing a global decline as a consequence of anthropic disturbs. For its conservation, it is necessary to know its geographical distribution and the main factors influencing it. Tandilia Mountains are located in the centre of Buenos Aires province, Argentina. These mountains contain high biodiversity and several endemic species, but the current Natural Protected Areas network covers a low area of ​​0.12 %. In this work, we modelled the geographic distribution of reptiles in the Tandilia Mountains to: a) explore the environmental factors affecting the distribution of reptiles on the highland grasslands of the Tandilia Mountain System and (b) identify the key biodiversity areas. We used ten environmental variables and several sources of records (fieldwork, scientific literature, museum collections, and an online database) to model the distribution of each reptile species. The best sites to propose natural reserves were determined in Zonation software. We determined the representativeness of the current system of Natural Protected Areas in the Tandilia Mountain range by overlapping the sites with the Zonation results. We obtained 20 species distribution models with two general patterns: continuous and patched. In most species, the two most informative variables were growing degree-days below 0 °C and precipitation of the wettest quarter. The current system of Natural Protected Areas of the Tandilia Mountains covers 0.35 % of the conservation priority sites (4341 km2) and therefore is insufficient in protecting reptile biodiversity.

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.

Population genomic structure in Goodman's mouse lemur reveals long-standing separation of Madagascar's Central Highlands and eastern rainforests.

Madagascar's Central Highlands are largely composed of grasslands, interspersed with patches of forest. The historical perspective was that Madagascar's grasslands had anthropogenic origins, but emerging evidence suggests that grasslands were a component of the pre-human Central Highlands vegetation. Consequently, there is now vigorous debate regarding the extent to which these grasslands have expanded due to anthropogenic pressures. Here, we shed light on the temporal dynamics of Madagascar's vegetative composition by conducting a population genomic investigation of Goodman's mouse lemur (Microcebus lehilahytsara; Cheirogaleidae). These small-bodied primates occur both in Madagascar's eastern rainforests and in the Central Highlands, making them a valuable indicator species. Population divergences among forest-dwelling mammals will reflect changes to their habitat, including fragmentation, whereas patterns of post-divergence gene flow can reveal formerly wooded migration corridors. To explore these patterns, we used RADseq data to infer population genetic structure, demographic models of post-divergence gene flow, and population size change through time. The results offer evidence that open habitats are an ancient component of the Central Highlands, and that widespread forest fragmentation occurred naturally during a period of decreased precipitation near the last glacial maximum. Models of gene flow suggest that migration across the Central Highlands has been possible from the Pleistocene through the recent Holocene via riparian corridors. Though our findings support the hypothesis that Central Highland grasslands predate human arrival, we also find evidence for human-mediated population declines. This highlights the extent to which species imminently threatened by human-mediated deforestation may already be vulnerable from paleoclimatic conditions.