Ian Lockwood

MUSINGS, TRIP ACCOUNTS AND IMAGES FROM SOUTH ASIA

Landcover Changes in the Palani Hills-A Spatial Study

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Lenny & Prasen on Dolphin’s Nose with Perumal peak in the far left. A panoramic composite image from January 2016.

The grasslands mapping project that took shape at the plantations conference in Kodaikanal in December 2014 produced a report that was published earlier this year. This is important work and represents the combined efforts of several disparate individuals, organizations and funding agencies. The preliminary visual assessment of Landsat imagery by the author showed that satellite data held spatial evidence of dramatic land cover change in the Western Ghats and Palani Hills but that it needed to be quantified. Robin Vijayan of ISER Tirupati put into motion a study in 2016 with key field work and spatial analysis being done by M. Arasumani and Danesh Khan. Further academic guidance was provided by Arundhati Das, Milind Bunyan and several others. Bob Stewart & Tanya Balcar, of the Vattakanal Conservation Trust, provided key insights on shola regeneration in plantations-the topic that originally brought everyone together. INTACH and ISER Tirupati helped provide funding of the field work. The Tamil Nadu Forest Department was an important stakeholder and helped provide permissions for the field work. Prasen Yadav joined the project to document the work and produce a video of the findings. The study was peer reviewed and published in January 2018.  It is publicly available on PLOS One, including access to all the tables of data and charts (see link below).

My involvement with the grasslands mapping brings together several interests and is the latest chapter in my ongoing interest and love affair with the Palani Hills. An alarming conclusion of the study is the great extent to which the montane grasslands have been taken over by non-native trees and weeds. Those of us who have been walking in the hills have had a sense of this but the satellite images providing damning proof. It is also clear that the plantations have spread far beyond the original boundaries that they were originally designed to be in. Most of the southern escarpment has a fire line etched into its grasslands and now plantations species are spreading beyond this boundary and down the steep slopes of montane grasslands. This leads to clear conclusion that where possible efforts need to be made to preserve these last remaining vestiges of montane grasslands. The challenge is that, in spite of the surprising resilience of shola tree species, the last montane grasslands are being steadily consumed by plantation (and some shola) species.

Our study concludes:

  1. Identify and conserve core grasslands: Core grassland areas consist of a few to many hectares of grassland encompassing hillocks, streams, marshes and rock outcrops. These areas, even when nestled in a plantation matrix, should be protected and form the core around which grassland restoration efforts should focus.
  2. Check invasion in sparsely invaded grasslands: These areas are often characterized by young plantations located in grasslands where grass cover is still extensive. Here, we recommend physical removal of invasive species. Forest departments often have access to significant funding through the Compensatory Afforestation (Bill passed in 2016) funds and these could be utilized for these activities. Such funds could be used for the restoration of marshes, existing grasslands and to manage the invasive plantations.
  3. Review indiscriminate removal of mature plantations: Mature plantations often have native shola forest regenerating under them and lack native grass cover. Grassland restoration here is likely to be very resource-intensive. Conservation efforts should focus on sparsely invaded and pristine grasslands. In mature plantations, we recommend conducting experimental or controlled studies (like at Vattavada, Munnar Kerala), perhaps also examining the role of fire, and monitoring soil and moisture conditions in these areas. Moreover, removal of mature plantations could stimulate regeneration of plantation species from saturated soil seed banks. Monitoring of these areas is important to assess the effectiveness of plantation removal.
  4. Contain agriculture: Our field surveys indicate that paddy cultivation has been discontinued in some marshes. Given the critical role of these marshes in regulating local hydrology, efforts should be made to contain agriculture to the current extent and restore these marshes using a community-led conservation effort.

Several other writes have reviewed the PLOS article in the popular press and I have listed articles in the Wire by Janaki Lenin, Mohan Rao in the Hindu and Pendharkar, Vrushal in Mongabay.

This year is a special year since it marks the cycle of Kurinji (Strobilanthes kunthianus) blooming that only happens every 12 years. Kurinji plants, more than any other grasslands species, are closely associated with healthy montane grassland systems. The extent of this year’s flowering will be a good gauge of the health of the grasslands of the Palani Hills.

My next personal chapter in this process to better understand the landscape and ecology of the Palani Hills is to present and share an exhibition of photographs and annotated maps at DakshinaChitra, Chennai this July. The next post will highlight this significant endeavor.

Southern escarpment on a very clear day looking west to the Agamalai range and beyond. January 2016.

REFERENCES & FURTHER READING

Arsumani, M. et al. “Not seeing the grass for the trees: Timber plantations and agriculture shrink tropical montane grassland by two-thirds over four decades in the Palani Hills, a Western Ghats Sky Island.”  PLOS One. January 2018. Web.

Lenin, Janaki “You’d Think Cutting Kodai Plantations Will Save Its Grasslands. It Won’t.” The Wire. 19 September 2017. Web.

Lockwood, Ian. “Mapping Montane Grasslands in the Palani Hills.” Ian Lockwood Blog. August 2016. Web.

“         “Land Cover Changes in the Palani Hills: A Preliminary Visual Assessment.” Ian Lockwood Blog. 4 April 2014. Web.

Montanari, Shaena (& Prasenjeet Yadav). “Breathtaking Sky Islands Showcase Evolution in Action.” National Geographic. 11 August 2017. Web.

Pendharkar, Vrushal. “Palani Hills: Where have the grasslands gone?” Mongabay. 20 February 2018. Web.

Rao, Mohan. “Missing the grass for the trees in Western Ghats.” The Hindu. 17 January 2018. Web.

Yadav, Prasenjeet. “Save our Shola Grasslands.” YouTube. Web-Video. 16 September 2017.

Written by ianlockwood

2018-05-28 at 11:56 pm

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