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This led to an even greater conversion of the grasslands in the form of vast tea estates and plantations of fast growing exotic tree species. MNP escaped this massive conversion of “wastelands” we think because of its very extreme climate on the western edge of the Nilgiri plateau. The park, a mere 70sq km is all that remains of this once vast landscape but a good deal more than the 5sq km we all worked on last year in the Palnis*. Everyone who visits the park is smitten by its beauty.
Our role ie the “Restoration Alliance”, an informal name, is as back-up for the Forest Department in dealing with invasives at the seedling cum sub-shrubby level which is highly labour intensive but suitable for volunteers who can be easily trained by those who are already experienced.
After a day of meetings we headed for Bangitapal in MNP. On the way we stopped to check up on two eradication trials taken up by the Restoration Alliance. The first was an eradication of Pinus patula from Mexico, the most widely used Pine for industrial plantations. Seedlings were removed from here in March 2011. There was no sign of re-invasion in the area cleared. This eradication also targeted outlying individual saplings with their potential to seed new areas of the grassland. At the meetings the need by the FD to remove “mother” plantation trees was emphasised.
Our next stop was to check up on a trial eradication of Scotch Broom in the upper reaches of the Upper Bhavani river basin. The introduction of this plant according to local folklore was undertaken by homesick Brits who wanted to make the landscape more like home. The irony of three Brits whacking away at it a century and a half later was not lost on our forester friends. It should also be noted that our headgear has changed – topis out of fashion!
Of all the methods tried the only really viable one was cutting the plant at its base and painting it with a mixture of engine oil and Glysophate weed-killer. Five months on there was no sign of any regeneration and no sign of any damage to native plants. We also went to look at an experimental clearance of Broom that was undertaken by the FD sometime after the 2004 Alliance meeting in Ooty. The area of the quite extensive clearance can be found along the long narrow stretch of the Upper Bhavani reservoir and the stream to its left. We found the grassland had made significant recovery but that Broom, untreated with weedicide, was reasserting itself.
Also back in March we had surveyed the catchment area to its brow overlooking MNP. We concluded the whole upper catchment area was entirely restorable and we found a brilliantly located camping area for Alliance teams to undertake the restoration.
From the hill top survey a large Shola was spotted in the middle distance. It was actually a square kilometre thicket of Gorse (Ulex europeus), no doubt another product of Euro homesickness. The concept of “containment” was put forward as a practical management strategy for the short term, ie that no new areas of the park should be allowed to be overwhelmed by any of these plants.
The FD did subsequently experimentally cull dense infestations of Broom and Gorse on the fringes of the park and cut a few hectares a year of A. mearnsii inside the park. Vistas began to appear that had not been seen for decades, but as A. mearnsii was removed our worries turned to Rubus fairholmianus/ellipticus, species of the Shola margin that explode into thickets when plantations containing them are removed.
It should be noted here that unlike most of the Palnis and elsewhere in the Nilgiris the grasslands being cleared of Wattle in Mukurthi has not been extirpated and can recover without further intervention.
The Demise of A mearnsii 2005 - 2014
In the spring of 2005 in the Palnis we began to note the trees sudden death on thin soils to begin with, suggesting drought stress but shifting to deeper soils as the year progressed. This dying off continued and intensified over the next two years. (Detailed account in the Rise and Demise of Acacia mearnsii, 2011).
We were pretty well convinced it was drought stress brought on by the exhaustion of soil moisture by this fast growing water hungry species. In 2009 an Australian hydrologist, Michelle Donnelly, described what she called a “boom and bust” scenario. The species had thrived, growing much larger than in its native Australia, but now was a victim of its own success. Earlier we had noticed huge blisters appearing on the trunks of trees known as cankers. Our research eventually found that a fungus common in the environment Botryosphaeria dothidea would infest lesions in sap wood of stressed trees, and in particular Acacia mearnsii where experimental infection had resulted in 90% mortality. After 2007 this became the main cause of death as opposed to direct drought stress. Today on the Palnis there is hardly a tree not infected, and the infection has taken hold in both the Annamalais (Botanical note 2011 – Pampadam Shola) and the Nilgiris. Even young trees with green bark are succumbing. We have not been able to confirm locally that the fungus killing the tree is actually Bothryosphaeria. We have tried to interest scientists for the last 6 years but to no avail which confirms for us the way botanical science is taught and practised here. Simply too much lab and reductionist experimentation. Not enough observation in the field, looking at the big picture.
Something though quite different has been happening in MNP. We first noted in two visits to the park the apparent death of millions of trees covering whole hillsides had occurred, though some resprouting was reported. The “March on Bangitapal” had stopped in its tracks. Also the thousands of A. melanoxylon seedlings we had recommended monitoring in “Notes-“ were all dead – just thin sticks in the ground. We think Mukurthi’s very extreme, wet, cold and dry seasons somehow accounts for the die off and the very existence of the park.
Returning to MNP in August 2013 we found what could only be described as the remains of hundreds of thousands of trees. It cannot be exaggerated how catastrophic the decline of A. mearnsii has been. If we appear to be banging on a bit, it is because people arriving new on the scene keep on themselves banging on about the threat of A. mearnsii and how we must get rid of it etc. They have no idea how vigorous and clearly invasive it was in the past. It is difficult for people newly coming, to appreciate how miserable and defeated the species is. This can result in misdirected and pointless “ecological restoration” ie removing Wattle “invading Shola”. Wattle has never invaded Shola and never will. Whenever you see Wattle and Shola growing together it is the far stronger, better adapted Shola that is invading and ultimately consuming the Wattle. In the Nilgiris for example targeting Acacia mearnsii “invading the Shola” would be a diversion from the much more serious problem of Cestrum auranticum which completely smothers Shola regeneration and is spreading to new parts of the Nilgiri plateau. This can be seen at Naduvattam following major road works through the Shola. We showed that eradicating Cestrum auranticum was possible during the last decade at Cairn Hill forest near Ooty.
At the Vattaparai marsh restoration our main task has been to tackle the seed bank of A. mearnsii. We have removed millions of seedlings over the last 7 years, but for the last 10 months the FD have withdrawn their permission for us to work on the marsh (and Bombay Shola) pending their final status vis a vis notification of the Kodaikanal Wildlife Sanctuary. We visited the marsh with our Conservator Akash Baruah with the hope of re-starting work soon. We discovered that our wells for measuring the water table, made over 4 years ago, had been systematically damaged beyond repair.
We should end on a cautionary note. Vasanth Godwin brought up the possibility of Black Wattle making a comeback. This would not be possible where Shola species are taking over, but seedlings do exist where the mass die-off has occurred in Mukurthi’s grasslands and they need be monitored.
Lastly and something that always has to be repeated Acacia mearnsii does not sucker from the roots and is easily killed if at all necessary by cutting hard to the base or below the base where it is more tender.
Botanical Note – Bangitapal, Mukurthi National Park
Robert Stewart & Tanya Balcar 25.08.15
It is two years since we last visited Bangitapal again accompanied by Suprabha Seshan of Gurukala Botanical Sanctuary and fellow trustee of VCT, Ooty resident Vasanth Bosco. Our purpose then (2013) was to re-engage with the FD on the subject of grassland restoration in and around MNP following our experimental (successful) trial eradication of Scotch Broom six months earlier.
Unfortunately no progress on grassland restoration was made as the Government policy was and seems to remain restoring Shola forest. As we have stated ad nauseum now for many years this is totally misguided as the forest component of the Shola/grassland eco-system is thriving and ever expanding into the exotic plantations where Shola becomes dominant eventually. We are currently all victims of our own obsolete propaganda that is at least 30 years out of date. Today for the first time the Hindu published a somewhat confusing article which confirms these realities if not entirely accurate from our point of view. Clear felling or “opening up” plantations is counter productive, encouraging weeds and the rejuvenation of the plantation species, further depleting recovering soil moisture.
Grassland Restoration
The FD have been trying to eradicate Wattle inside Mukurthi for some years now. A lot of this has been eradication of already dead trees. The grassland landscape across the Upper Bhavani dam towards Bangitapal has been opened up, but regeneration of Wattle is there from light, medium to heavy. The further East (towards the dam) the more intense the regeneration. The hillsides above this arm of the reservoir is where we, the “Restoration Alliance” would like to renew our voluntary assistance to the FD’s efforts. We can also tackle Rubus (wild Raspberry) infestation. A dab of Glysophate (Roundup) on a cut stem is highly effective and does not damage surrounding vegetation. Rubus has spread towards Bangitapal following major road works and accompanying disturbance.
We also spotted a few new small colonies of Ulex europeus (Gorse) and Cytisus scoparius (Broom) inside the park. These need to be controlled before they explode across the park. Vasanth has spotted the same in Western Catchment. It is likely there is more.