Taxus wallichiana Zucc. is an endangered medicinal tree species valued for its production of paclitaxel, but its conservation is constrained by overexploitation and poor natural regeneration. This study evaluated the feasibility of propagating T. wallichiana by apical cuttings under nursery conditions as a conservation-oriented alternative to seed propagation and lateral cuttings. Two-year-old donor plants subjected to apical shoot removal produced a cumulative 25.93 +/- 0.84 suitable shoots per plant after 12 months, providing a reliable source of propagules. Rooting performance was significantly affected by IBA concentration, rooting substrate, and cutting length. Among the tested treatments, 1.0% IBA was the most effective concentration for root induction. The best rooting performance was obtained in a substrate containing 25% sand and 75% coir dust, with a rooting percentage of 90.00 +/- 5.00%, 8.13 +/- 0.12 roots per cutting, and a mean root length of 4.83 +/- 0.24 cm. Apical cuttings 10-15 cm in length rooted better than 15-20 cm cuttings. For nursery growth, potting media containing 75% soil + 25% coir dust or 50% soil + 50% coir dust gave the best performance, with 100% survival and plant heights of 30.93 +/- 0.66 cm and 30.33 +/- 0.56 cm, respectively. After 18 months, cutting-derived plants reached 81.43 +/- 2.13 cm in height and 1.15 +/- 0.05 cm in basal diameter, outperforming seed-derived seedlings. These findings indicate that apical cutting is a promising propagation approach for conservation and restoration of T. wallichiana.
The spatial distribution of deciduous forests (DF) in Vietnam is relatively restricted. However, these ecosystems play a pivotal role in overall ecosystem structure and function. This study aimed to assess the environmental drivers governing the distribution of DF in Vietnam under climate change scenarios. Our results show that DF currently occupies a relatively narrow climatic niche spanning approximately 10,496.49 km2, predominantly in the Central Highlands. Precipitation of the driest month, temperature seasonality, and elevation emerged as the dominant predictors of DF distribution. Projected climatic niche contraction for the period 2081-2100 ranged from 7.6% (SSP245) to 33.2% of the current climatically suitable area (SSP585). This decline is primarily associated with increased precipitation during the coldest quarter and greater temperature variability. These findings underscore the need for targeted and proactive conservation strategies for DF in the Central Highlands of Vietnam, where the already limited suitable habitats are particularly susceptible to climate-driven range contractions.
Species distribution models (SDMs) are widely used to infer potential species ranges, yet their ecological reliability in rapidly transformed landscapes remains poorly understood. We applied Maximum Entropy (MaxEnt) modelling to estimate the potential distribution of twelve forest-specialist butterfly species of high commercial value across West Africa, with a focus on C & ocirc;te d'Ivoire, Ghana and Liberia, based on bioclimatic covariates. Models showed good predicted performance (mean jackknife AUC = 0.854, significantly better than random; null model test p < 0.01), driven by both precipitation-related variables (i.e. precipitation seasonality; 57.4% of explained variance in model predictions) and temperature-related variables (annual mean temperature, 33%). However, spatial predictions showed limited concordance with contemporary forest cover: 45.23% in Liberia but only 4.69% in Cote d'Ivoire and 6.42% in Ghana. Key refugia such as Ta & iuml; Forest (Cote d'Ivoire) were partially underpredicted. To evaluate whether the observed agreement between predicted habitat suitability and forest cover reflects genuine ecological associations or is instead driven by spatial bias, we developed a probabilistic framework in which the expected overlap is defined as the product of forest availability and suitability probability. Building on this null expectation, we derived a Habitat Matching Index (HMI), expressed as the ratio between observed and expected overlap, allowing us to quantify deviations from random spatial association and to distinguish ecological signal from patterns generated by habitat availability alone. HMI values differed markedly among countries (Cote d'Ivoire: 0.319; Ghana: 0.570; Liberia: 1.407), demonstrating that apparent model performance is strongly influenced by forest extent rather than ecological fidelity alone. These findings reveal a fundamental limitation of climate-based SDMs: high statistical accuracy does not necessarily imply ecological realism. Integrating habitat availability into model evaluation provides a critical correction, improving inference in heterogeneous and rapidly changing tropical landscapes. We advocate combining climatic, land-cover, and species-specific data to enhance SDM reliability in conservation biogeography.
Our study attempted to find a spatial analogue of the anticipated climate change in present times by investigating the status and development trends of four half-century-old man-made Scots pine stands outside the species areal in Central and North-Eastern Bulgarian lowlands. Stand composition, competition intensity, stand stability, site quality, tree mortality and ecosystem fit according to nationally established standards, were evaluated and growth correlations with climatic variables were analysed. Two stands experiencing an ongoing dieback were distinguished, regardless of the good productivity potential of the trees (Stand 2) or the low competition pressure and good mechanical stability maintained (Stand 1). The other 2 plantations showed either no mortality (Stand 4) or mortality due to self-thinning (Stand 3), forming a relatively productive and dense pure Scots pine stand (Stand 4) or a mixed, highly productive stand with diverse composition and good structure and stability (Stand 3). Tree growth was positively affected by the summer and the annual precipitation amounts, while negative correlation was found with the summer heat moisture index. Our investigation revealed that pine growth still can be sustained even in a slightly humid climate, if a high productivity level and good stand structure are assured, that indicates the overall capability of the species to adapt. However, the Scots pine trees are not able to adapt to relatively dry environmental conditions, suitable for lowland thermophilic species such as oaks, where the stands collapse when the heat-moisture balance worsens.
The identification of natural succession and regeneration processes is crucial for the preservation of biodiversity and ecosystem stability in sustainable forest management. This study investigated the biodiversity and regeneration of natural forests and Liquidambar excelsa (Noronha) Oken plantations. Tree species richness (dbh >= 10 cm) in natural forests was found to be significantly higher (44 species) than in plantation forests (5 species, 4 of which were natural recruits). Although tree density was higher in natural forests, basal area was lower than in plantations. At the regeneration (sapling) level, species richness did not differ significantly between the two forest types, with a moderate diversity index and high evenness, and a species similarity of 60.7%. However, sapling density and basal area were higher in the plantation forests. For understory vegetation, species richness was also not significantly different, but the diversity index was higher in the natural forests. Both shared a very high species similarity (75.6%), despite the greater density and cover in the natural forests. The successful recruitment of native species into plantations is more influenced by environmental factors such as proximity to natural forest seed sources and topography, rather than by the forest type itself. This is demonstrated by the discovery of L. excelsa seedlings in natural forests and the presence of several native species that have successfully regenerated in plantation forests, indicating the potential for biodiversity restoration.
