Predation is a strong driver of prey behaviour and sympatric species are likely exposed to similar selective predatory pressures. We test the hypothesis that this leads to similar anti-predator behaviours using the widespread Neotropical snake tribe Pseudoboini as our model. We reviewed and compiled documented defensive behaviours for all species, adding new unreported behaviours for three species. We used a cluster analysis to generate a matrix of defensive behaviour dissimilarity between species. We then used a phylogenetic generalized linear mixed model to test how behaviour dissimilarity changed with geographical overlap, similarity in ecological traits, and phylogenetic relatedness. Only 41 species had available data on defensive behaviour, with only 22 of those represented in the phylogeny. We found that similarity in defensive behaviour is significantly (albeit not strongly) correlated with geographical overlap, but only for species with similar body sizes. Phylogenetic relatedness by itself was a poor predictor of behaviour dissimilarity. This corroborates our hypothesis that defensive behaviours are spatially structured at larger scales but that this can be modulated by morphological differences. Testing inter-species ecogeographical differences of defensive behaviour and its implications can be broadly applied to other taxa.

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.

The ultimate measure of the success or failure of conservation initiatives in an area will be the ecological health of that area and the sustainability of institutions which support that ecological health. Heretofore, no comprehensive data has been presented about the current conservation state of the area known as the Heart of Borneo (HoB), a mostly intact subset of the island of Borneo, which is an international conservation priority. This paper identifies a set of indicators representative of the biodiversity status of the HoB; collecting and analysing data concerning these indicators and combining these data with supplemental conservation information should provide an accurate assessment of the overall conservation state of the HoB. Based on the indicators identified in this study, the general biodiversity status of the HoB is rated as good, or viable, although there are specific elements of concern. Using the threat indicators identified in this study, the overall threat level is medium. Major threats from industrial forest conversion and mining currently exist mainly on the edges of the HoB, but are likely to expand further inland without any intervention simply based on proximity. Though most habitats within (but not outside) the HoB are generally intact, the current protected area system is insufficiently representative of the natural ecosystems of the HoB area and its management effectiveness is as yet unknown.