Thursday 4 September 2014

Lantana: India's Innovation Inspiring Invasive

About a month ago my attention was drawn towards this episode of Plants: From Roots To Riches. Approximately 4 minutes and 10 seconds in, the discussion turns to the invasive species Lantana camara.  Shonil Bhagwat of The Open University talks about the spread, management and utilisation of Lantana in India, which led me to do my own research on the subject. So here goes!

Firstly, the basic facts. Lantana is an aromatic invasive weed, originating from South and Central America. Introduced to India in the early 19th century for ornamental hedging (look how pretty it is!), Lantana has since spread across India (as well as many more countries), despite numerous attempts to contain and reduce its range.

Lantana camara in all its prettiness
The global distribution of Lantana camara. Quite the jet-setter.
In Northern India, the biomass and diversity of vegetation has been shown to decrease in areas where Lantana has become prevalent (Singh et al., 2014). Lantana is able to dominate over native vegetation due to its ability to alter soil chemistry using its own litter .

Sneaky...

Lantana camara in all its sneakiness.
And just look at the consequences. Look at them!

The effects of Lantana (black bars) in comparison to control areas (white bars) on the density and biomass of vegetation in northern India (Singh et al., 2014).
And the issues aren't just limited to the north of India. Kannan et al (2013) report that in southern India Lantana poses a serious threat to native biodiversity. For example, the amount of Phyllanthus emblica has reduced by 16% in 10 years in southern India (Kannan et al., 2013).

However, all may not be as bleak as it seems.

Communities in southern India have found ways to incorporate the invasive plant into their livelihoods. People have been utilising Lantana for a range of activities including basket weaving, furniture construction and as fuel wood.

Various Lantana user groups and uses (1 Lantana stick collection by Madigas; 2 Lantana basket weaving by Irulas; 3
Lantana basket ready for sale; 4 Lantana sticks boiling by Soligas; 5 Lantana furniture making at MM hills;
6 Lantana sofa) Kannan et al (2013).
Kannan et al (2013) suggest that those who utilise Lantana can gain 46% of their income from Lantana related activities.

Relative income sources for users and nonusers of Lantana (Kannan et al., 2013)
This demonstrates that human ingenuity can help make the best of what appears to be a bad situation. Though there has been a loss of income from forest resources, gains have been made via using the invasive Lantana as an alternative resource. So not only is a problem invasive being partially removed, its removal is benefiting local people.

From a human geography perspective (not a phrase I say often...) it's important to recognise that the use of Lantana was not instigated by external agencies (Kannan et al., 2013). This is a local solution. Communities have evolved their own processes and technologies to work with Lantana as a substitute for depleting bamboo species.

Over the course of this blog I've come across numerous management techniques, but this is the first locally developed management programme I have encountered. As the Lantana case shows, an invasive species 'problem' can lead to adaptive management. The locally developed solution is helping to tackle the invasive issue and also helping to alleviate poverty  (Kannan et al., 2013) . Win win!

Over and out

The Invader Inspector

Shonil's blog 'Reflections on nature and culture', featuring some posts on invasive species as well as other environmental issues, can be read here