Over the years more than 200 wildlife rangers in the Virunga National Park have lost their lives in the line of duty.
Salmon in the Klamath River in the United States were once abundant. They no longer are.
Plastic waste has reached catastrophic proportions in the oceans and it is increasing further still.
Compared to coffee, a popular cash crop, avocado is more tolerant of variations in precipitation.
The 7,000sqm rooftop garden at Thammasat University is the largest such green space in Asia.
Termites can be important for ecosystems in semi-arid lands like grasslands and savannahs.