Three South American Nassella species ( N. neesiana, N. tenuissima and N. trichotoma) have naturalized in South Africa but have not yet been reported in Lesotho. Of these, N. tenuissima and N. trichotoma have been recognized as serious invaders since the 1970s. Assessing their current and future distributions is crucial for understanding the threats they pose in both countries. This study addressed the following questions: 1) What key bioclimatic variables control the geographical distribution of these species? 2) What is the current potential distribution range? and 3) What is the future potential distribution under three carbon-emission scenarios using estimates for the period 2071-2100? Nine non-collinear predictors from the CHELSEA database were selected for Maxent species distribution models. These models were projected under future climate scenarios, incorporating three Shared Socioeconomic Pathways (SSPs) from five global circulation models. Results showed that temperature-related variables, particularly mean diurnal range, were critical for all species, while precipitation in the driest month also influenced N. trichotoma. Results suggest that all three species can potentially occupy a greater area than they currently occupy. While highly suitable area is predicted to contract for all species, the Maloti-Drakensberg region-including in Lesotho-is predicted to become increasingly suitable. This poses a severe risk to the endemic-rich biodiversity and rangeland productivity. Much of Lesotho is affected by overgrazing and other disturbances which favor Nassella establishment. Proactive surveillance directed at early detection of Nassella incursion into Lesotho should be given high priority. (c) 2025 The Author(s). Published by Elsevier Inc. on behalf of The Society for Range Management. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/)

The three non-native Nassella species (N. neesiana, N. tenuissima, and N. trichotoma) occurring in the South African montane grasslands are morphologically cryptic, and hence difficult to distinguish from several taxonomically complex, co-occurring tufted C3 perennial grass genera (e.g. Festuca), and amongst one another, especially when in a vegetative state. DNA-based species identification, as has been demonstrated with other plants, offers a possible solution. This study evaluated the use of single nucleotide polymorphisms to identify and differentiate between Nassella species. Two gene loci, petL-psaJ (petL) and ETS were used to discriminate the three Nassella species from each other, and from three native grass species (Aristida diffusa, Festuca caprina, and Koeleria capensis) and the non-native species Jarava plumosa. The result showed that the petL locus could only discriminate the different genera while EST locus could differentiate all the tested species. The cost of outsourcing the whole process to a genetic laboratory is reasonable, making DNA-based species identification a viable identification method for non-experts. With this tool, early detection of Nassella populations is now possible so that management can be implemented before the species spreads beyond control.

Nassella trichotoma (Poaceae) is a highly invasive South American grass that is invading montane grasslands in the Eastern and Western Cape provinces of South Africa. Although N. trichotoma has been recognised as a major problem in these mountains for decades, the primary concern has been on impacts on rangeland productivity and management, while the impacts of invasions on plant biodiversity have not been considered. To understand the impact of N. trichotoma on local plant biodiversity, 81 pairs of plots (total of 162 plots) were laid out in the Sneeuberg and Eastern Cape Drakensberg mountains, Eastern Cape, in March 2020 and March 2021. At each site plots were located in grassland invaded by N. trichotoma and in nearby uninvaded grassland (control). A total of 20 N. trichotoma patches were sampled with two to four plot pairs per site. All vascular plant species were recorded in all plots, the cover abundance of each species per plot was visually estimated, and the topsoil was sampled and analysed for differences in nutrient and physical factors between invaded and uninvaded plots. Plant species diversity was 24 % higher in uninvaded areas, and the native grasses Pentameris airoides (Chi(2) = 4.93, d.f. = 1, p < 0.01), Tenaxia disticha (Chi(2) = 5.51, d.f. = 1, p < 0.01), and Themeda triandra (Chi(2) = 9.28, d.f. = 1, p < 0.001) were significantly less abundant in invaded plots. Uninvaded areas had greater native species diversity (65 species) and fewer alien species (3) than invaded areas (47 and 9 respectively). Of the 18 soil variables measured, the following were significantly higher in invaded areas than uninvaded areas: boron (23 %), calcium (18 %), phosphorous (58 %), silt (10 %), total cations (12 %), and zinc (68 %). This suggest that N. trichotoma alters soil nutrients. The results indicate that N. trichotoma is a powerful driver of native biodiversity erosion in these montane grasslands and should be a cause for major concern by landowners and government.

Significance StatementInvasive alien plants (IAPs) in South African mountains are both threatening and supporting ecosystem services and human well-being for local communities, as well as those in nearby lowland areas. Higher elevation mountain areas have distinct IAP compositions compared to lower elevation mountains due to their unique climatic conditions. Management of IAPs in these montane settings presents many challenges and needs to work on multi-value-based approaches that ensure the inclusion of communities in the decision making. We advocate for more mountain-specific research that can guide and upscale National Resource Management to implement programmes that are relevant to the socio-ecological circumstances in these high elevation areas.

This book deliberates on developments related to Knowledge Pathing: Multi-, Inter- and Trans-Disciplining in Social Sciences. The book explores the value of this vexed concept in advancing the course for multi-, inter- and trans-disciplinary perspectives, methodologies, theories and epistemologies of knowledge pathing. The discourse on knowledge pathing remains critical in advancing debates and dialogues in the humanities and social sciences spaces of research and studies. This book makes a significant contribution to the scholarly understanding of indigenous knowledge research by focusing on problematising local indigenous community research from Afro-sensed perspectives. The field of indigenous knowledge research and higher education in Africa is complex. Yet, across the continent, higher education has been the sector to least embrace Indigenous Knowledge Systems (IKS) or regard indigenous science as a legitimate source of inspiration for the development of youth and local communities. Higher education institutions and local indigenous communities should thus generate knowledge and power through research. On the other hand, higher education researchers should use their research processes and skills for cross-beneficiation when engaging local indigenous communities. This book embodies the current discourse on decolonisation and the use of indigenous knowledge in research and is intended for research specialists in the field of indigenous knowledge systems.

High-elevation Afroalpine ecosystems of the Drakensberg Mountain Centre (DMC) of Lesotho and South Africa, renowned for their high endemism and key ecosystem services, are socio-ecological systems that have seen human activity for millennia. However, their responses to land management practices are understudied. Controversy over their natural state has also led to conflicting policies and management emphases. Focusing on the crucial ecosystem-modulating component, grasses (Poaceae), we evaluate the response of DMC Afroalpine vegetation to human impact through grazing and burning. Grass species associations were recorded from grassland, shrubland and wetland-riparian-seep ecotypes across a range of grazing and fire regimes to document relationships between abiotic conditions, disturbance, and taxonomic diversity and composition. CCA of grass community composition retrieved a large cluster of plots of mixed grazing and burning regimes with no particular environmental vector correlated with them. Other smaller groups of plots separated from these were associated to heavy grazing, bioclimatic variables, slope gradient, and aspect. Indicator species analyses found DMC endemic grasses were associated to low grazing, while alien grasses were associated to heavy grazing. GLMs found little difference between ecotype-disturbance categories with regards plant species richness, mean alpha hull=2 range-size of native and sub-Saharan endemic grasses, and site-level Sørensen beta diversity (βsor). Some differences were noted, including the highest cover and proportion of DMC endemics being found in low-grazed grassland, and highest cover and proportion of alien grasses and highest plot-level βsor being found in heavily grazed ecotypes. Relative importance analyses found grazing regime to be the main influence on cover and proportion of DMC endemic and alien grasses. Partial Mantel tests found mean annual temperature and grazing regime to be the main influence on plot-level βsor. Synthesis: Taxonomic diversity and composition of DMC Afroalpine grasslands was relatively unaffected by moderate grazing and intense burning, although heavy grazing had a largely detrimental impact, with its ubiquity across the DMC a major cause for concern. High levels of endemism, coupled with the above data emphasizing the robustness of DMC grasslands to disturbance, also supports Afroalpine grasslands as a natural component of the DMC. This research reinforces the natural grass-dominated nature of the DMC as a social-ecological system where sustainable management is possible thanks to its resilience to grazing and burning, although current widespread overgrazing requires urgent attention.

Background: The grasses (Poaceae) of the Flora of Southern Africa (FSA) region (i.e. Botswana, Eswatini, Lesotho, Namibia and South Africa) are relatively well documented, for both native and non-native species. Visiting taxonomic expertise nevertheless reveals new FSA and in-country records, particularly of non-native species. Such records provide an opportunity for improving biosecurity relating to potentially invasive but hitherto undetected non-native Poaceae in the FSA region.Objectives: To improve floristic data for non-native Poaceae occurring in theFSA region.Method: Field collections were made, herbarium collections, databases and relevant literature were studied.Results: New records are presented for non-native grasses that were encountered as locally common populations in the Drakensberg Mountain Centre of Floristic Endemism (DMC, Lesotho and South Africa). Festuca rubra and Agrostis capillaris are newly reported for sub-Saharan Africa and southern Africa and are also the first verified specimens reported for the African continent, with previous reports from northern-most Africa (Morocco, Algeria and/or Tunisia) uncertain. Jarava plumosa, introduced from South America and previously known for the whole of Africa from a single population in the Western Cape, South Africa, is newly reported from the border between the Eastern Cape, South Africa and Lesotho. The ecological implications, including the potential to become invasive, are discussed for each species, with taxonomic notes given to help differentiate them from closely resembling taxa.Conclusion: These new records of alien grass species raise concerns over their potential ecological impact, particularly as they are found in an area of conservation importance. Future efforts to monitor their distribution are of importance.

Three species of Nassella have naturalized in South Africa. Nassella trichotoma and N. tenuissima are declared weeds under category 1b of the National Environmental Management: Biodiversity Act (NEM:BA) and occur mainly in the montane grasslands of the Western and Eastern Cape provinces. Nassella neesiana is not listed in NEM:BA but is naturalized in the Eastern Cape, Western Cape and Free State provinces. Research conducted in the 1970s and 1980s led to vigorous government-funded awareness and control campaigns which ended in 2000. No research on Nassella distribution or control has been undertaken since then. Despite this hiatus, Nassella remains a dangerous genus in southern Africa, given the serious impacts of these species in similar social-ecological systems in Australia and New Zealand. This paper presents a synthesis of available information about Nassella invasions in South Africa and identifies research gaps. It specifically addresses these questions: What identification issues exist? What is the current spatial distribution of Nassella? What is the autecology of the genus? What are the social-ecological impacts of Nassella? What control measures are currently applied and what are their strengths and limitations? What do we know about Nassella distribution and its response to climate change? This paper highlights many knowledge gaps about Nassella, such as the species' current distribution range, field identification and detection difficulties, and the uncoordinated control efforts that require urgent research to inform an effective management response. (c) 2020 SAAB. Published by Elsevier B.V. All rights reserved.

Three species of Nassella have naturalized in South Africa. Nassella trichotoma and N. tenuissima are declared weeds under category 1b of the National Environmental Management: Biodiversity Act (NEM:BA) and occur mainly in the montane grasslands of the Western and Eastern Cape provinces. Nassella neesiana is not listed in NEM:BA but is naturalized in the Eastern Cape, Western Cape and Free State provinces. Research conducted in the 1970s and 1980s led to vigorous government-funded awareness and control campaigns which ended in 2000. No research on Nassella distribution or control has been undertaken since then. Despite this hiatus, Nassella remains a dangerous genus in southern Africa, given the serious impacts of these species in similar social-ecological systems in Australia and New Zealand. This paper presents a synthesis of available information about Nassella invasions in South Africa and identifies research gaps. It specifically addresses these questions: What identification issues exist? What is the current spatial distribution of Nassella? What is the autecology of the genus? What are the social-ecological impacts of Nassella? What control measures are currently applied and what are their strengths and limitations? What do we know about Nassella distribution and its response to climate change? This paper highlights many knowledge gaps about Nassella, such as the species’ current distribution range, field identification and detection difficulties, and the uncoordinated control efforts that require urgent research to inform an effective management response.

The first comprehensive plant checklist for the Bvumba massif, situated in the Manica Highlands along the Zimbabwe-Mozambique border, is presented. Although covering only 276 km2, the flora is rich with 1250 taxa (1127 native taxa and 123 naturalised introductions). There is a high proportion of Orchidaceae and Pteridophyta, with both groups showing a higher richness than for adjacent montane areas, which may be due to the massif's relatively high moisture levels as a result of frequent cloud cover. However, in contrast to other mesic montane regions in southern Africa, there are relatively few near-endemic or range-restricted taxa: there is only one local endemic, Aeranthes africana, an epiphytic forest orchid. This is likely to be an effect of the massif having limited natural grassland compared to forest, the former being the most endemic-rich habitat in southern African mountains outside of the Fynbos Biome. Six other near-endemic taxa with limited distribution in this portion of the Manica Highlands are highlighted. The high number of invasive species is probably a result of diverse human activities in the area. The main species of concern are Acacia melanoxylon, a tree that is invading grassland and previously cultivated land, the forest herb Hedychium gardnerianum which in places is transforming forest understorey with an adverse effect on some forest birds, and the woody herb Vernonanthura polyanthes which invades cleared forest areas after fire. Future botanical work in the massif should focus on a more detailed exploration of the poorly known Serra Vumba on the Mozambican side and on the drier western slopes. This will allow for a more detailed analysis of patterns of endemism across the Manica Highlands.

C-4 photosynthesis is a complex trait that boosts productivity in tropical conditions. Compared with C-3 species, the C-4 state seems to require numerous novelties, but species comparisons can be confounded by long divergence times. Here, we exploit the photosynthetic diversity that exists within a single species, the grass Alloteropsis semialata, to detect changes in gene expression associated with different photosynthetic phenotypes. Phylogenetically informed comparative transcriptomics show that intermediates with a weak C-4 cycle are separated from the C-3 phenotype by increases in the expression of 58 genes (0.22% of genes expressed in the leaves), including those encoding just three core C-4 enzymes: aspartate aminotransferase, phosphoenolpyruvate carboxykinase, and phosphoenolpyruvate carboxylase. The subsequent transition to full C-4 physiology was accompanied by increases in another 15 genes (0.06%), including only the core C-4 enzyme pyruvate orthophosphate dikinase. These changes probably created a rudimentary C-4 physiology, and isolated populations subsequently improved this emerging C-4 physiology, resulting in a patchwork of expression for some C-4 accessory genes. Our work shows how C-4 assembly in A. semialata happened in incremental steps, each requiring few alterations over the previous step. These create short bridges across adaptive landscapes that probably facilitated the recurrent origins of C-4 photosynthesis through a gradual process of evolution.

C-4 photosynthesis is a complex trait that boosts productivity in warm environments. Paradoxically, it evolved independently in numerous plant lineages, despite requiring specialised leaf anatomy. The anatomical modifications underlying C-4 evolution have previously been evaluated through interspecific comparisons, which capture numerous changes besides those needed for C-4 functionality. Here, we quantify the anatomical changes accompanying the transition between non-C-4 and C-4 phenotypes by sampling widely across the continuum of leaf anatomical traits in the grass Alloteropsis semialata. Within this species, the only trait that is shared among and specific to C-4 individuals is an increase in vein density, driven specifically by minor vein development that yields multiple secondary effects facilitating C-4 function. For species with the necessary anatomical preconditions, developmental proliferation of veins can therefore be sufficient to produce a functional C-4 leaf anatomy, creating an evolutionary entry point to complex C-4 syndromes that can become more specialised.

This study assessed woody species diversity, composition and vegetation structure in a dry forest Miombo woodland at Mazowe botanical reserve. All woody species were systematically identified and measured in 45 sample plots. Analysis of inventory data was done using Microsoft Excel. Four vegetation communities identified along the river, anthills, hills and slope areas of the reserve were demarcated. Relative Density, dominance, frequency, and species and family importance values were computed to characterize the species composition. A total of 108 woody species belonging to 78 genera and 41 families were recorded. Members of the Fabaceae subfamily Caesalpinoideae were dominant with 6 genera and 9 species. Stem densities/ha were high ranged from 572 on the anthills to 2040 along the river valley. The dbh distribution showed an inverse “J” shaped curve, meaning that there is active regeneration and recruitment in the woodlands. Shannon-Wiener Index of diversity values ranged from 1.85 in the slope area to 3.42 on the anthills showing high species diversity in the reserve. This study reveals that the Mazowe botanical reserve has a high species richness and diversity. This is mainly due to the diversity of habitats like river valleys, anthills, streams, hills and slopes for species establishment. A number of anthropogenic activities have been recorded in the reserve notably fire and tree cutting. These require further detailed assessment to evaluate their impact on the woodland dynamics.