Abstract Afromontane ecosystems, characterised by mosaics of fire‐adapted grassy ecosystems and fire‐sensitive forests, are biodiversity hotspots facing escalating pressures from non‐native species, climate and land‐use change. Madagascar's Central Highlands is one such hotspot, hosting woodlands dominated by endemic Uapaca bojeri (tapia) which are important to local livelihoods and biodiversity conservation. Despite their social–ecological importance, multi‐decadal dynamics of tree cover remain poorly understood, particularly differential responses from native versus non‐native tree species to socio‐ecological drivers. We investigated tree cover trajectories across the Central Highlands by integrating ground‐based vegetation surveys (40 plots), historical remote sensing analysis (80 sites) spanning 73 years (1949–2022), and traditional ecological knowledge (TEK) documented through 32 focus groups with 114 members of community forest management associations. We examined whether native tapia woodlands declined as has been widely assumed, how non‐native forestry species (Pinus spp. and Eucalyptus spp.) spread and the factors driving these dynamics. Tapia woodlands showed multi‐decadal (1949–2022) structural stability confirmed by both remote sensing (−0.52% change, 𝑝 = 0.0810) and TEK shared during 81% of focus groups. TEK revealed compositional change within superficially stable tapia stands, with losses of companion species. Non‐native forestry species cover increased substantially (+17.4%, 𝑝 < 0.001) over the same period, with expansion accelerating after 1991. Expansion was greatest near roads, with model predictions indicating +26% total increase at roadside sites compared to sites far from roads over 73 years (Year × Distance to Road: β = −0.152, 𝑝 = 0.002). Synthesis. Tapia woodlands demonstrate structural resilience, challenging widespread narratives of human‐driven deforestation in the Central Highlands of Madagascar, although compositional losses of companion species reveal that not all biodiversity within stable canopies is equally conserved. Meanwhile, rapid non‐native encroachment poses increasing threats to ecosystem services that rural communities depend on. Integrating TEK with remote sensing facilitated detection of compositional losses and offers a transferable framework for monitoring heterogeneous landscapes that have been challenging to monitor using conventional methods. Read the free Plain Language Summary for this article on the Journal blog. French translation: Read the free Plain Language Summary for this article on the Journal blog.
The Cyperaceae family, with over 5,600 species, is a major component of open ecosystems worldwide. In Madagascar, where open grassy ecosystems dominate, the family remains understudied. We assessed Cyperaceae species composition, richness and endemicity across closed (forest), dry open (dry grasslands, rocky outcrops, bare dry soils), and wet open (marshes, swamps, wet grasslands, riparian areas) habitats in Isalo National Park and the Itremo Massif Protected Area, both in Madagascar's Central Highlands. Fieldwork spanned 40 days during which Cyperaceae specimens were collected along survey routes. Soil samples were collected from 20 habitats (5 closed, 6 wet open, and 9 dry open) and analysed for pH, nitrogen, soil organic carbon, potassium and phosphorus to evaluate their influence on species composition via co-inertia analysis. We recorded 108 species across 12 genera, 28 of which are endemic to the island. The highest richness and number of endemics were found in the dry open habitat (72 species, 20 endemics), followed by the wet open (60 species, 7 endemics). Closed habitat had the lowest number (14 species) but a higher endemism rate, with 7 endemic species. Species composition was most similar between wet open and dry open habitats (beta(SOR )= 0.5), and least similar between closed and dry open habitats (beta(SOR) = 0.91). Soil characteristics did not differ significantly among habitats, except for potassium, and they did not affect species composition. The results highlight the importance of the Central Highlands for Cyperaceae, as they are home to at least a third of native Cyperaceae species in Madagascar.
In recent years, Biophytum umbraculum Welw. (Oxalidaceae) has undergone several phytochemical and pharmacological investigations. Although its major phytochemical classes have been characterized, few isolated compounds have been reported. The previously detected phytoconstituents, along with the documented antioxidant and anti-inflammatory activities, both align with a potential antiproliferative effect. This study aims to complement the existing chemotaxonomic profile of B. umbraculum through the isolation and identification of phytoconstituents and to evaluate the antiproliferative potential of its extracts. Hexane, ethyl acetate, and methanolic extracts of B. umbraculum were screened against two human adherent cell lines, breast (MCF-7) and cervical (SiSo) adenocarcinomas, by using the crystal violet staining assay. The hexane extract inhibited both MCF-7 and SiSo cell proliferation with IC50 values of 8.93 +/- 0.07 and 14.59 +/- 0.08 & micro;g/mL, respectively. The ethyl acetate extract showed activity against both cell lines, with IC50 values of 12.60 +/- 0.14 and 13.10 +/- 0.04 & micro;g/mL, respectively. However, the methanolic extract was inactive on the MCF-7 cell line and only slightly active on the SiSo cell line. Chromatographic fractionations led to the isolation of ursolic acid from the active ethyl acetate extract and rutin from the methanolic extract. A further antiproliferative evaluation is warranted to confirm the contribution of ursolic acid to the effect of the ethyl acetate extract. Additional fractionations may uncover more phytoconstituents of diverse pharmaceutical interests.
Recent research has improved the understanding of the Poaceae family in Madagascar, particularly in terms of taxonomy. These studies have facilitated better identification and classification of species. However, little attention has been given to alien and invasive Poaceae weed species, despite their important role in ecological dynamics. This gap highlights the need to investigate the invasive potential of this plant family, which can significantly impact Madagascar's ecosystems. In this study, we aim to advance the understanding of Poaceae invasions by reviewing existing data and highlighting key insights to support Madagascar's invasive species management. We developed a comprehensive checklist of 154 Poaceae weeds and/or alien species based on literature reviews and online databases to ensure accuracy and comprehensiveness. Our goal was to categorise these species into groups with three distinct management recommendations: prohibited species, species that need to be monitored and those considered harmless. Each of these categories was defined based on its estimated ecological impact and invasiveness potential. Among the 154 species assessed, we confirmed the presence of 56 species introduced to Madagascar and identified one species that we suggest should be prohibited in Madagascar. Based on our assessment, we propose a precautionary approach for species that are not yet invasive but pose a threat. Additionally, we highlight species that should be subject to risk analysis to assess their invasive potential. By developing these recommendations, we hope to assist in the creation of effective strategies for managing Poaceae invasions in Madagascar and to support broader conservation efforts.
Life Cycle Assessment (LCA) offers a comprehensive and rigorous framework for evaluating the environmental performance of buildings across all stages of their life cycle. This study assesses the full life cycle impacts (construction, operation, renovation, and demolition) of Amphitheatre 1001 at the University of Yaound & eacute; I and evaluates the effectiveness of several mitigation strategies. Using the PLEIADES software suite, which integrates dynamic thermal simulation and LCA modelling, five scenarios were analysed: mobility management, photovoltaic (PV) solar energy production, a combined mobility-PV scenario, rainwater harvesting, and building orientation. Results reveal that the combined mobility and PV scenario delivers the largest environmental benefit, achieving a 45.57% reduction in greenhouse gas emissions and an average cumulative reduction of 26.42% across all impact categories over an 80-year life cycle. The PV-only scenario yields an average reduction of 18.07%, while mobility management alone achieves 8.35%. Rainwater harvesting produces a marginal improvement (0.23%), and orientation changes have no measurable influence on environmental performance. These findings highlight the critical role of integrated energy and mobility strategies for achieving significant environmental gains in high-occupancy educational buildings located in tropical regions.
