The Malabar river-lily (Crinum malabaricum) is endemic to five sites on rivers in northern Kerala, south-western India and was described new to science in 2012. In 2016 it was assessed as Critically Endangered using the IUCN criteria; however research has shown that whilst still vulnerable, populations are fairly secure. The Red List Assessment for C. malabaricum needs to be revised, probably to Vulnerable D2, based on the small number of populations. Research projects were carried out in 2017 and 2022 in collaboration with students and staff of the Government College Kasaragod, funded by grants from the Mohamed Bin Zayed Species Conservation Fund, to assess the conservation condition of C. malabaricum and to devise a monitoring protocol. This report presents the results of the second project.
Four of the sites supporting Crinum malabaricum (at Aravanchal, Cheemeni, Embate and Periya) were visited on the 25th-27th September 2017 and four (at Aravanchal, Cheemeni, Eramam and Periya) on the 3rd-5th October 2022. C. malabaricum occurs on seasonal rivers flowing over level laterite at 80-100 m above sea level, in an area 20 x 5 km in Kannur and Kasaragod Districts, running parallel to the coast of northern Kerala. Populations appear to be limited upstream by reaches involving faster flow among bedrock outcrops and downstream by deeper water over silt.
Population estimates based on detailed recording at Periya suggest that the global population is in the region of 25,500 individuals distributed as follows: Aravanchal 500, Cheemeni 5,000, Embate 12,000 and Periya 8,000 individuals. All known populations have been abundantly fertile in both 2017 and 2022, flowering and setting seed abundantly from early September to late October. Potential seed-set in the population at Periya was estimated to be 2,250-33,750 in 2017 and 11,505-172,575 in 2022. Although C. malabaricum is capable of growing in full sunlight, this is rare, and most populations occur in the shade either of natural riparian woodland and scrub or fruit crop plantations. C. malabaricum typically forms dense stands covering the entire channel with leaves forming a dense mat as water levels drop. Due to its size and growth form, it grows with few other plant species, although where instream habitats or human activities reduce the cover of C. malabaricum, a range of other species occur such as Eriocaulon heterolepis, E. dalzellii, Lagenandra toxicaria and Cryptocoryne spiralis. Where the canopy is more open, other species may occur, such as Blyxa aubertii var. echinosperma, Limnophila aquatica and L. repens, with grasses such as Isachne globosa, Oryza rufipogon and Sacciolepis interrupta on the margins.
All the rivers which support populations of C. malabaricum have been extensively modified by man, mostly with a 2-3 m high wall of laterite blocks along one or both margins, other significant modifications are mainly associated with road crossings. Where there are significant interventions, such as major crossings or sites where people regularly use the channel, this creates gaps in the stands of C. malabaricum. C. malabaricum is a major ecosystem architect, providing shelter for fish and invertebrate communities, dramatically modifying the hydrology of the rivers and almost certainly playing an important role in nutrient cycling.
Overall, known populations of C. malabaricum may be considered stable and relatively secure, although there is potential for local actions to affect all populations. There is a suggestion that populations are in unfavourable condition at Cheemeni due to the rubber plantation, threatened at Aravanchal by housing and possibly declining at Embate due to development. There is a need for monitoring at all these sites to establish population trends. The apparent absence of a mechanism for formal protection of sites supporting C. malabaricum highlights the need for surveys of potentially suitable habitat within the known range of the species, as well as for monitoring of all know populations to identify population trends. More importantly, there is a need for a major initiative to stimulate and support conservation of wetland plants throughout the Western Ghats, to ensure conservation of C. malabaricum species and other taxa endemic to the region.
Project 192522500 location - India, Asia