Visit to Pampadam Shola June 1st 2010. Notes on some ongoing ecological processes
Bob Stewart & Tanya Balcar, Vattakanal Conservation Trust, Kodaikanal
We first visited Pampadam Shola in 1987, walking from the Kerala side to Berijam. Our last visit was during 1994. We were somewhat disappointed with our first visit. At no time did we feel we were walking inside the Shola. The forest edge was always at some distance from the track and weedy thickets obscured visibility of the Shola floor.
On this visit, accompanied by Mr Ramesh of WWF, our most marked impression after 16 years was that the forest has inched closer to the road through natural regeneration, but that weedy thickets still persisted in many parts. We feel that spot planting of Shola saplings could help speed up roadside regeneration and help reduce weed thicket intensity. This was a point we raised at last years “Shola Grassland National Park” meeting in Munnar. Nevertheless at our meeting with the Wildlife Warden after visiting Pampadam, Mr Babu offered his view that “natural regeneration is best” - a view we wholeheartedly agree with and hope that foresters on the ground will communicate this fact to policy makers in each relevant State capital. We feel there is so much more that could be done to improve eco-system services and diversity if the concept of ecological restoration went beyond tree planting.
We visited the experimental Eucalyptus plantation en route to Vattavada that had been planted in 1998. Invasion of Shola species here was very advanced even after only 12 years. Careful selective removal of Eucalyptus where it has already served to nurse Shola regeneration looked feasible here.
Alongside the Eucalyptus we found an old Acacia mearnsii stand where most of the trees were suffering from a fatal fungal canker disease (large swellings at the base and trunk). The pathogen is most likely a fungus in the Genus Botryosphaeria (see our website, subpage under “The Rise & Demise of Acacia mearnsii”). This fungus is known to attack Acacia mearnsii in particular and most particularly under conditions of drought stress brought on by depletion of soil moisture.
Acacia mearnsii will access ground water if it is available. Australian hydrologist Michelle Donnelly described it here in the Palnis as “a boom and bust scenario”. Her colleague Dr Ray Froend stated, “AM is indeed a facultative phreatophyte. If groundwater is accessible it will use it. Roots can be deep but it is a real problem over shallow water tables where it significantly increases transpirational discharge and prevention of recharge. All of the best work on the species (in relation to water use and catchment hydrology) is from South Africa.”
See this link for references http://www.issg.org/database/species/references.asp?si=51&fr=1&sts=&lang=EN
Shola regeneration was also apparent especially of Litsea wightiana along with a good number of emerging Rubus thickets.
At the other end of the Shola beyond the wireless station at the fire tower we examined the (unburnt) Wattle plantation. There was much less evidence of the canker infection here which we attributed to higher rainfall and less stress at this altitude. Shola invasion of the plantation was light here being some distance from the Shola – but still bound to intensify over time. The plantation floor was dotted with Rubus ellipticus plants.
Grassland and Shola restoration. Exotics: To cut or not to cut?
The Wattle at the wireless station and above is an example of where cutting in the name of restoration (grassland) would be disastrous. Rubus (native) and other weeds would quickly take over. The Rubus thicket at the wireless station is a good example of what would happen over large areas.
Rubus thicket by the wireless station, emerging after cutting of Wattle
Any attempt at grassland restoration where the plantation species has completely extirpated the grassland eco-system would require enormous inputs of weeding and revegetation with native species. Ideally exotics should be removed where the grassland eco-system is intact enough to heal itself after the exotics have been removed.
Sometimes there may be a fifty fifty situation. Where weeds and native grassland plants may compete post felling. Observations in the Palnis show that weeds overcome natives. In such a situation the weeds have to be actively repressed. (See our website; Vattaparai marsh restoration)
Where Shola saplings invasion of plantation is intense removing large exotics could do more harm than good. In the case of Wattle the Shola will quickly eliminate it.
Here taking out the smaller Eucalyptus plants would cause minimum damage to the emerging Shola (Mannavan Shola)
At Blackburn Shola near Kodaikanal we have witnessed the complete conversion of Wattle plantation to Shola over hundreds of acres in the last 25 years.
Shola will out-compete both Eucalyptus and Pine in time.
Shola regeneration under Pine planted in 1973 (Palni Hills)
Where Shola invasion is light due to distance from the Shola and grassland restoration is not feasible as at the watchtower and wireless station, the Wattle plantation could be hand seeded with Shola species to speed its conversion to Shola.
In the Shola we spotted a tree. We think a Litsea. It has glabrous, elliptic leaves, that shine brightly red in the spring. The fruit (fairly small) is shallowly 2 lobed ripening to a dull red/purple – the seed is globose. We have this tree in the Palnis, but has not been identified.
At the top end of the Shola there is a good deal of a shrubby Strobilanthes. We have found the species at one location in the Palnis. Does anyone know its identity?
A few years ago our local FD gave us seed from a tree we identified as Litsea coriacea. The dried seeds failed. We cannot locate the tree – a new record for the Palnis. The fruit is very small for a Litsea, occurring in dense clusters. Gamble says the tree is found at 4000ft in the Annamalais. Can anyone help with seed?
Please note; A. mearnsii does not sucker from the roots therefore uprooting is not necessary. Cutting at the base is enough.
Lastly Rubus species continue to proliferate here in the Palnis (and Mukurthi National Park) wherever gaps appear in plantation coupes. We really need a serious scientific evaluation of its pathological – or otherwise effect on our “novel” emerging eco-system.
Thanks to the Wildlife Warden, Munnar for giving permission for our visit and to Mr Ramesh of WWF for guiding us for the day.