Replanted rainforests may benefit from termite transplants
(Photo credit: Dr Baptiste Wijas )
Despite a bad reputation for their destructive abilities, termite ‘transplants’ may be necessary to give regenerated rainforests a boost.
A multi-year study in the Daintree region led by visiting University of Queensland academic Dr Baptiste Wijas found termites were not thriving in former farmland replanted with rainforest species.
Dr Wijas, from Cary Institute of Ecosystem Studies, said while many people — including forest managers — did not like termites, the insects played an important role in a healthy forest ecosystem.
“People tend to think that by just planting a diversity of trees, these rainforests will regenerate,” Dr Wijas said.
“But should we actually be putting in other organisms as well, to restore other ecosystem processes that help the forest function?
“Termites are essential for recycling nutrients and carbon from dead timber and the insect’s slow recovery could be hindering the growth and health of the young forests.”
The researchers put wooden blocks in old growth and replanted forests and assessed the termite activity over 4 years.
(Photo credit: Dr Baptiste Wijas)
To assess how decomposers such as termites and fungi functioned in replanted areas, the team placed blocks of wood at 3 sites – an old growth area in the Daintree Rainforest and 2 nearby former plantation sites replanted 4 and 8 years prior to the start of the study.
They checked the wooden blocks every 6 months over 4 years for fungi and termites, and also measured how quickly the blocks were decomposing.
Based on previous studies in South America, the researchers expected termite activity to be similar in the old growth and replanted forests, and fungal decay rates to be lower in the younger forests.
Instead, they found the opposite – termites were slower to decay the wood blocks in the replanted forests while fungi were functioning similarly in both.
Cary senior scientist Dr Amy Zanne said lower rates of termite-driven decay could mean a slower return of carbon and nutrients to the soil, harming forest health and future growth.
The researchers suggest transplanting deadwood logs from old growth rainforests to newer forests to boost abundance and diversity, while also providing a food source for decomposers.
“A young, regenerating forest doesn’t have a lot of dead wood in it,” Dr Zanne said.
“So, if you bring in these logs, you’re giving them some food to tide them over while they wait for parts of trees to start falling.”
Dr Zanne said only about 3 per cent of termites are known to damage houses, while very little is known about the other 97 per cent and she and Dr Wijas were working to understand the role termites have in rainforests and other ecosystems.
The team says transplanting termite mounds into new forests along with deadwood should also be studied in the future.
The research was published in the Journal of Applied Ecology.
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