Pinanga represents one of the largest genera of palms and has been extensively collected by botanists, though ecological studies on Pinanga remain limited. We evaluated species diversity and assemblages of Pinanga palms in two contrasting forest types, heath forest (HF) and mixed Dipterocarp forest (MDF) in Brunei Darussalam located in the Borneo biodiversity hotspot. At three HF and three MDF sites, all Pinanga palms greater than 5 cm height within a 3-ha sampling area per site were recorded and taxonomically identified. Selected soil properties (total N and P concentrations, pH, gravimetric water content [GWC] and OM) and environmental variables (litter depth [LD], humidity, canopy openness [CO] and elevation) were determined for each study site. Our survey recorded a total of ten Pinanga species, comprising 981 individuals. Pinanga abundance was significantly higher in HF sites than in MDF sites, while Pinanga abundance and species richness significantly varied between sites. Patterns in Pinanga species assemblages were significantly influenced by soil properties and elevation in the MDF sites but were only influenced by CO and LD in the HF sites. We identified three Pinanga species found in both forest types: Pinanga lepidota, Pinanga salicifolia and Pinanga mirabilis, while seven Pinanga species were exclusive to MDF sites and none were exclusive to HF sites. Two Pinanga species (Pinanga chaiana and Pinanga veitchii) were recorded as singletons and thus are in urgent need of protection. The restricted distributions of these Pinanga species within Borneo signifies a need to tailor specific conservation strategies in their native habitats to avoid their local extinction.

Heath forests, or known locally as kerangas, in Indonesia and Malaysia form a distinct and understudied ecoregion. We document the distribution and ecological significance of the largest extent of kerangas in Kalimantan, Indonesian Borneo. We mapped 16,586 km2 of kerangas to the nearest one square kilometre across Kalimantan, showing a significant reduction from previous estimates. About 19% of this area exists as a poorly documented mosaic landscape in Central Kalimantan’s Rungan-Kahayan region. Here, peat-based forests transition to heath and dipterocarp forests, making it difficult to reliably classify these forests for conservation planning. Using remote sensing and tree plot data, we identified three forest types—kerangas, low pole, and mixed swamp. Vegetation structure is influenced by soil, topography, and hydrology, while peat depth and elevation affect species diversity. Our findings indicate that these forests are dynamic ecosystems with diverse vegetation communities adapted to peat as well as sandy soils. Lowland heath forests in Rungan-Kahayan exhibits higher tree densities compared to other Bornean heath forests, reflecting unique ecological adaptations to challenging environments. Despite covering just 3% of Kalimantan’s forest area, these ecosystems remain largely unprotected, facing threats from land conversion and fire. Our study highlights the ecological complexity of kerangas and underscores the urgent need for targeted conservation and further research on these forests.

Semecarpus calcicola is an endangered tree restricted to Pulau Mantanani, Malaysia. New data of population size and structure was used to reassess the IUCN threat category of this species. Results are based on twenty-six 400 m2 plots in a 26.5 ha area that included the majority of Semecarpus calcicola’s known population. GLMs were used to investigate the relationship between the number of individuals and elevation. Estimates of the population size for each size class were determined using Horvitz-Thompson estimators, generalised regression estimators and spatial linear models and extrapolated to the study area. Elevations of the plots were obtained from a digital elevation model as auxiliary data. Significant relationships were found between the number of individuals and elevation. Mature individuals are more common at higher elevations, whilst seedlings, saplings and poles are more abundant in the lower elevation plots. Land-use change due to the increase of tourism activities and the local community drives the significant decreases of mature individuals within the lower elevation. Introduced cattle, tourism-related land-use change and plantation activities further threaten the population of S. calcicola, particularly smaller individuals due to herbivory. The estimate of population size varied among the methods and size classes. The estimated number of mature individuals ranged from 509 to 764.

While blue fluorescence has previously been reported in several genera of carnivorous plants, green fluorescence has not been formally documented in previous literature. Here, we present the first confirmed record and qualitative documentation of vivid green biofluorescence in a member of the genus Nepenthes (Nepenthaceae). This study aims to examine this distinctive trait and interpret its ecological and taxonomic implications. The specimens exhibited intermediate morphological characteristics—including leaf margins lined with brown hairs, distinctly petiolated leaves, and a peristome bearing spike-like teeth—indicating a hybrid origin between two sympatric species, N. benstonei and N. rafflesiana. Under UV light (365 nm excitation), the peristomes of mature pitchers from the Nepenthes hybrid (N. benstonei × rafflesiana) exhibited intense green fluorescence. In contrast, both putative parental species emitted blue fluorescence: N. benstonei uniformly across its peristome, while N. rafflesiana displayed sparse yellow-green streaks on its peristome. The natural hybrid was discovered at elevations of 700–900 metres above sea level (MASL) in the Timur Range, Peninsular Malaysia, with only nine individuals recorded. In addition to providing preliminary data on the occurrence of an undescribed taxon, this represents the first recorded instance of green autofluorescence in Nepenthes—hitherto unobserved in the wild—that may contribute to its insect-luring strategy. Our findings underscore the rich biodiversity of the region’s rainforests and highlight the urgent need for conservation efforts to safeguard these ecosystems, which may harbour as-yet-undiscovered taxa.