The large floating mats choke off sub-surface species such as fish and turtles from light and oxygen and support organisms harmful to human health.
Annual economic impacts in seven African countries alone have been estimated at between US $20 million and $50 million; Africa-wide, costs are thought to reach US $100 million. In Mexico, more than 40,000 hectares of reservoirs, lakes, canals and drains are infested. In China, the annual costs of water hyacinth management are estimated at around $1.3 billion, and in the US its economic harm is estimated at $120 billion. In California, the weed has severely impacted the Sacramento-San Joaquin River Delta.
Taking off: the use of flying robot drones on environmental missions
Tracking the spread of floods and other natural disasters, chasing wildlife poachers, mapping deforestation, detecting illegal mining or logging, and sniffing out volcanic threats are among the growing uses environmental scientists are making of unmanned flying robot drones.
According to UNEP, "eco-drones" offer a relatively low-cost way to collect atmospheric data, for example, or real time, high resolution images offering information unobtainable from satellites and ground surveys.
Notable early applications:
Authorities in Sao Paulo, Brazil, have deployed 14 drones (cost: US $350 million) to monitor deforestation in the Amazon, track poachers and detect illegal mining. And in 2012 the World Wildlife Fund received US $5 million from Google to deploy drones and other technologies to track animal poachers in Africa.
The US Nat
|Contact: Terry Collins
United Nations University