Juffe Bignoli, D., Narasimhan, D., Kumar, V.S., Ravikumar, K. & Rao, M.L.V.
Aponogeton satarensis is only known from five sites in small temporary pools on the top of widely separated hill plateaus in the Western Ghats. At one of these sites, some of the temporary pools have been lost due to the construction of windmills however, secondary pools have been created and the species is has colonized these new pools. Another site is threatened by the increase of tourism (botanical amateurs) and litter disposal. Hence, the habitat quality of these sites is degrading due to increased pollution, changes in micro habitats by earth removal, littering and garbage disposal and unintended fires in summer caused by tourists and grazers. Other sites are being claimed for mining of laterite, although no pressures are active at the present except for grazing, which has been going on for several years. In the study that was conducted for three years from 2004-2006, decline was not observed although habitat modifications was observed in some of the known localities. Despite this, population decline in the next 10 years is expected due to increasing human pressures on the known sites. The species is assessed as Endangered as it has a restricted area of occupancy and extent of occurrence, and there is an ongoing a decline in habitat quality in most of the known locations.
This species has been reported from Mhavashi (which is the type locality), Kas, Patan ferricretes in Satara district and Gothane ferricrete in the Western Ghats which falls under Ratnagiri district political boundary. The fifth locality is Chalkewadi plateau in Satara district, Maharashtra (A. Watve pers. obs. 2004-2006). It is also known to occur in Amboli area, Maharashtra (S.R. Yadav pers. comm. 2003).
Estimated area of occupancy (AOO) - km2:
Continuing decline in area of occupancy (AOO):
Extreme fluctuations in area of occupancy (AOO):
Estimated extent of occurrence (EOO) - km2:
Continuing decline in extent of occurrence (EOO):
Extreme fluctuations in extent of occurrence (EOO):
A population study of this species was made in two localities and other which were rigorously surveyed for three years (Watve in litt.). The population size was estimated to be 1,500 mature individuals with the largest subpopulation containing 500 individuals. A decline in mature individuals was not observed from 2004-2006 although habitat modifications were recorded in some of the localities. Population trend for the global population is not clear.
Primary habitat of this species is monsoonal rock pools of about 20 cm depth formed on ferricretes at altitudes above 800 m in the northern Western Ghats. It secondary habitat may be in water filled ditches formed by soil removal where it grows well for about two years.
Continuing decline in area, extent and/or quality of habitat:
The main threats for this species are habitat disturbance due to construction of windmills leading to major changes in surface drainage. Removal of soil and increased garbage also disturbs the species. In one site, increased tourist pressure leads to trampling of primary habitat. This species being a well known attraction to plant lovers and photographers is often targeted by the tourists leading to habitat disturbance.
According to an earlier flora, one locality is threatened by the construction of a dam. This is highly improbable now (A. Watve pers. obs 2010). The site is remote, at the top of the mountain, highly protected as it is core zone of a newly created Wildlife Sanctuary (Chandoli) and perhaps is the best protected location for this species.
Ex-situ conservation efforts have been done by individuals and institutions including Botanical Survey of India, however none have been successful as the habitat requirements are too specific. More concentrated efforts are needed for a long term for ex-situ conservation. At present conservation of habitats is the best measure (A. Watve pers. obs. 2010) as well as reducing impacts mentioned in the threats section.