Frogs under pressure from illegally released invasive species at Chadwick Lakes

Frogs at Chadwick Lakes are fighting for survival because of crayfish that were introduced illegally into the valley and the capture of tadpoles, the authorities have warned.

The Painted Frog is Malta’s only native amphibian but its population in Chadwick Lakes has been put under pressure by crayfish that prey on them. Crayfish are an invasive species that have thrived in the valley.

However, crayfish are not the only alien species introduced illegally at Chadwick Lakes, with the authorities warning against the release of fresh water fish and ducks.

Chadwick Lakes is a protected valley of crucial importance to rainwater harvesting and is currently undergoing extensive rehabilitation works by the Energy and Water Agency and Nature Trust Malta-FEE.

In a joint statement, the organisations noted with satisfaction that the ongoing restoration efforts that include the removal of silt, the construction of rubble walls and footpaths, have attracted more visitors to the site.

However, they insisted that a protection notice issued earlier this year has specifically prohibited certain activities in the valley that could harm the delicate ecosystem.

The release of any non-indigenous species into the valley system is strictly prohibited. The agencies underscored the logistical and financial challenge to eradicate invasive non-native species.

But they also warned against the capture of tadpoles and their removal from the valley, which is also an illegal practice.

Extensive restoration works have increased the capacity for rainwater catchment while ensuring that soil erosion is minimised

“Following the interventions to remove alien species, the indigenous species populating the valley bed are once more beginning to thrive. However, this rehabilitation process is severely impacted by human activity upon the valley bed, irrespective of whether such activity involves foot or vehicular traffic,” the agencies cautioned.

The impact of foot traffic might not appear to be as extensive to the naked eye as car tracks, they said, however, they both have a “significant impact” with respect to living organisms as and the valley’s function in contributing to groundwater recharge.

The protection notice prohibits off-roading, including off-roading by motorcycles, and limits access by vehicles and bicycles to existing hard surfaces.

For visitors enjoying the site on foot, a clearly marked walking trail is being established and access to the valley will be improved.

“Keeping to the clearly marked pathway and refraining from straying onto agricultural land or into the valley bed itself allows visitors to interact with the valley in a way which is respectful of its ecological importance and of the agricultural activity,” the agencies said.

Visitors to the valley are also requested not to discard litter along the footpath but to use the bins that are being provided at each end of the walk.

Further information about the project may be obtained by visiting the dedicated website here.