Analogous environments across the tropics have similar levels of tree species alpha diversity Shumei Xiao, Jonathan M Adams, Shufeng Li, Ferry Slik, Daniel M Griffith, et al. National Science Review, 2026 Different regions of the tropics vary in overall tree species diversity, with the tropical Americas exhibiting strikingly higher regional tree species richness than Africa and Southeast Asia. We investigated whether these differences also occur at the local scale and whether the environmental conditions associated with tree species richness are consistent across tropical regions despite highly dissimilar species pools. A spatial random forest model was trained by using a network of 429 1-hectare plots across the tropics, together with 24 environmental variables, to predict plot-level tree α diversity. A combination of climatic, soil and topographical variables explained ∼86% of the variation in richness. Despite differences in regional species pools and the potentially disruptive effects of different geological, climatic and evolutionary histories, the relationship between environmental variables and local-scale tree species richness is closely similar across different continents. Our findings imply a pervasive role of niche-based mechanisms in structuring local tree species richness, regardless of the regional species assemblages. This pantropical convergence in the richness–environment relationship poses a challenge for ecology to explain.
Potential Geographical Distribution of the Wheat Streak Mosaic Virus and its Impact on Food Security: Prediction Based on Modelling Using Climatic Factor Emmanuel Der Tambile, Raji Pushpalatha, Vilayannur Subramanian Ramachandran 2024 IEEE Global Humanitarian Technology Conference Ghtc 2024, 2024 Climate change has a major effect on the world's food production systems through outbreaks and spread of vector-borne and non-vector-borne crop diseases that affect farmer's incomes and national economies. This study predicts the distribution of Wheat Streak Mosaic Virus (WSMV) from 2021-2040 using historical and future climate data and WSMV species data. Using a maxent species distribution model with a Training AUC of 0.899, Test AUC of 0.884, and a True Skill Statistic of 0.697, potential regions for WSMV distribution are identified. Isothermality of 15-33, precipitation in driest month between 10mm-300mm, mean diurnal temperature of 11°C and above; annual temperature range of 25°C-34°C; precipitation seasonality not exceeding 7; precipitation in coldest quarter of 50mm–250mm; and precipitation of driest quarter of 25mm-250mm will influence WSMV distribution. We recommend strict enforcement of cross-border plant protection regulations, empowerment of local farmers, and integration of national-level response in risk's preparedness plans.
Selective logging intensity alters the population stand structure of cullenia-mesua-palaquium dominated tropical wet evergreen forest of the western ghats, South India V S RAMACHANDRAN Applied Ecology and Environmental Research, 2019 The present study was conducted in a population structure of selectively logged tropical wet evergreen forest, Cullenia-Mesua-Palaquium (CMP) forest series in the tropical wet evergreen forests of the Nelliampathy Hills, Western Ghats. The study was aimed to focus on how selectively logged treatment influences the density and basal area of CMP forest series stand structure. We sampled the number of individual trees (≥ 1 cm dbh, diameter at breast height) of CMP at 30 sites (20 × 50 m quadrat size), covering an area of 30.8 hectare (ha) in total. A total of 5936 tree individuals sampled had a mean density of 246 ha-1 and basal area of 20.73 metre square (m2) ha-1 from an area of 0.1 to 2.5 ha. Tree density per hectare and basal area differed significantly among plots with different logging treatments. Tree density and basal area were significantly lower in highly logged plots as compared to moderately logged and unlogged plots. The density of smaller trees was significantly higher in moderately logged plots. We suggest that heavy logging treatments might be a serious threat to the CMP forest series and may possibly alter its population structure and that the moderately logged treatments showed positive impacts on CMP stand structure and regeneration.
First record of Elytraria acaulis (L.F.) Lindau (acanthaceae) from the Kerala state and its distribution extension in India V. S. Ramachandran, M. Remesh Check List, 2016 Elytraria acaulis (L.f.) Lindau (family Acanthaceae) is a perennial herb that is distributed in tropical Africa and Peninsular India. In India, this plant has been recorded from Northern Circar, Deccan, and Carnatic regions, on the eastern side of Peninsular India. We present here a new record from the Walayar Reserve Forest in Palakkad District, Kerala, which is the first known occurrence of this species from the western side of the peninsula. This species is added to the flora of Kerala state.
Status and distribution of Humboldtia bourdillonii (Leguminosae), an endangered tree species of the Western Ghats, India Tropical Ecology, 2014
