Population ecology, threats, status and conservation of natural populations of Crotalaria longipes - an endangered plant

Crotalaria longipes is an endangered plant endemic to Kolli hills. It is one of the fifteen species listed in the Red Data Book of Indian plants. Initially field visits were made to locate the plant at Kolli hills. The general field observations revealed that the distribution of this species is limited to a very narrow range, the Kolli Hills, Tamil Nadu, India. C. longipes was found in association mostly with Lantana camara, and Solanum pubescens. The extent of occurrence and the area of occupancy of C. longipes were calculated from the map. The extent of occurrence was found to be 24-sq. km. and the area of occupancy was approximately 4 sq. km. Two populations of Kolli hills, were taken up for a detailed population study. Hundred plants from both populations were sampled. It was found that nearly twice the number of seedlings was found in population 2 than in population 1. There were no plants of height more than 4 m in population 2. Seekuparaipatti population was denser than the Solakadu population. Mature plants were 13 and 22 in number in Solakadu and Seekuparaipatti populations respectively. The leptidoteran insects associated with these plants indicated to the presence of pyrrolizidine alkaloids in these plants. Germination of seeds at the site was very low. Seeds were brought to the laboratory and acid scarified which helped in germination. The germination percentage obtained was 85.3 and 86.6 in population 1 and population 2 respectively. The gene bank stored seed (germinated after scarification after a year) exhibited a slight reduction in the germination (79 and 81 in population 1 and 2 respectively). The status of C. longipes was analyzed using the IUCN criteria (Mace and Stuart,1994). The probability of extinction was calculated based on the population reduction, extent of occurrence, number of mature individuals and the population estimates. The plant was given the status of critically endangered. Human influences on populations were also studied. The local perception about this plant was studied and the locals were encouraged to conserve this plant.