A study on ecology conservation and utilization of Diospyros Crumenata thwaites in Kerala an endangered tree of the Western Ghats

Abstract

An extensive field survey of Diospyros crumenata, a threatened tree distributed in theWestern Ghats of Kerala, identified major populations in the Vazhachal, Peechi-Pattikkadforests and isolated individuals in the Chimmony WLS in Thrissur District. Based onpopulation size, the species was assessed as Critically Endangered. The low percentage of pre-reproductive trees, as assessed by an inverted J-shaped curve, lower values of the ImportanceValue Index (IVI), and poor seedling counts indicate a declining trend in the population. Thespecies primarily inhabits wet soils and watercourse areas, serving as microhabitats. Thespecies' habitats are under threat due to power projects, road expansion, and the risk of forestfires. The dioecious trees showed irregularities in flowering, abnormal abscission of flowersand immature fruits, assumed to be ineffective pollination due to insufficient insect pollinatorsin a short period of blooming. The sweet, aromatic, fleshy fruit pulp was consumed along withthe seeds by mammals, resulting in an estimated 70% seed loss, which negatively impacted thesoil seed bank and seedling regeneration. The recalcitrant seeds on scarification followed bysoaking in tap water for 24 hours improved germination to 100% within 15 days compared to66% germination within 24 days of sowing in control sets. The seeds stored in closedpolycarbonate containers in the controlled conditions of the seed bank, 20± 2°C; 40% RH,showed extended viability for up to 10 months. The application of auxin, IBA at 3000 ppm,resulted in stem rooting of 70% within 60-70 days under controlled nursery conditions,compared to 20% in the control set. Air -layering success of 100% was achieved with NAA at5000 ppm, while the control set did not induce rooting. Acute oral toxicity tests of the ripe fruitpulp on adult Wistar rats revealed no toxicity. The nutritional analysis of the ripe fruitsindicated that they are more nutrient-dense than commonly cultivated fruits. The evaluation ofthe seeds revealed significant mineral content, chemical content, antioxidant activity, and thepresence of promising bioactive compounds. The habitat distribution model, developed usingMaxEnt software, identified potential distribution areas in the Western Ghats of Kerala,pinpointing suitable niche models for species reintroduction. Seed and seedling infestationscaused by fungal pathogens were identified at the molecular level, enabling effective diseasemanagement.