Conservation of crinum malabaricum Lekhak and S R Yadav Amaryllidaceae a critically endangered aquatic angiosperm

Abstract

Conserving critically endangered plant species requires a multifaceted approach combining ecological, molecular, in situ, and ex situ strategies. Crinum malabaricum Lekhak & S.R.Yadav, a rare and endemic aquatic plant found only in seasonal laterite pools of Northern Kerala, faces significant threats due to habitat fragmentation, changes in hydrology, and human disturbances. This study aims to develop a comprehensive conservation framework by assessing the species' ecological requirements, identifying key threats, exploring its evolutionary lineage, and implementing integrated conservation measures. Ecological and phenological assessments were conducted to understand the habitat requirements and reproductive biology of C. malabaricum. Field studies confirmed that its life cycle is closely linked to seasonal monsoon patterns, and its limited dispersal mechanism further restricts its range. Habitat suitability assessments revealed that, despite identifying new potential sites since 2016, the area of occupancy (AOO) of the species remains critically low. This reinforces its Critically Endangered (CR) classification under IUCN Red List criteria. Phytochemical analyses were carried out to determine the bioactive properties of C. malabaricum, revealing significant alkaloid content with notable antioxidant and acetylcholinesterase inhibitory activities. These findings underscore the pharmacological potential of the species, which highlights the importance of conservation initiatives that incorporate sustainable utilization strategies. Molecular phylogenetic analysis utilizing ITS and trnL-F markers has shed light on the evolutionary lineage of the species, confirming its close genetic relationship with Crinum thaianum from Southeast Asia. The study indicates that C. malabaricum likely evolved as a neo-endemic species due to the unique climatic and geographical conditions of the Western Ghats, diverging from its ancestral lineages traced to Southeast Asia and Pacific Island biotas. This genetic distinctiveness highlights the need for targeted conservation efforts.To support species recovery, Ecological Niche Modeling (ENM) was employed to identify suitable sites for translocation. This method successfully guided the reintroduction of C. malabaricum to selected locations within the Malabar Plain, serving as a pilot initiative for long-term conservation. Additionally, ex situ conservation efforts were implemented, including cryopreservation techniques and the maintenance of live collections at the Malabar Botanical Garden and Institute for Plant Sciences. A novel potting method was developed to ensure the species' survival under controlled conditions, thereby securing a genetic reservoir for future restoration efforts. Additionally, habitat restoration and protection measures were undertaken to mitigate threats and promote community-led conservation initiatives. A formal proposal was submitted to the Kerala State Biodiversity Board to designate the natural habitat of C. malabaricum as a Local Biodiversity Heritage Site (LBHS) under the Biological Diversity Act, 2002 (Amendment act, 2023). This study serves as a model for developing species-specific conservation strategies by integrating ecological research, molecular insights, and conservation technologies. It emphasises the importance of long-term monitoring, habitat protection, and sustainable use of resources. By connecting scientific research with conservation efforts, this study contributes to the broader goal of preserving endangered aquatic flora and other biodiversity in the laterite plateaus of the Western Ghats and beyond.