Friday is U.N. World Wildlife Day, which aims to celebrate and raise awareness of the world's wild animals and plants. This year's theme is "Listen to the Young Voices," but many campaigners warn that future generations may never see many of the species around today because they are on the brink of extinction, mostly because of human activity.
That includes the hidden wildlife beneath the oceans, at increasing risk from the huge amount of plastics filling our seas — from microbeads in cosmetics to industrial-scale waste.
"Twelve million tons of plastic is entering the oceans every year, which is about a rubbish truck's worth of plastic every single minute," said Louisa Casson of Greenpeace's London office. "Plastic is entering every single level of the ocean food chain, and marine creatures from zooplankton up to blue whales are choking on plastics. They are ingesting it, and they are getting tangled up in it."
Around the world, the United Nations warns, human activity is depleting biodiversity. In many parts of Africa, elephants and rhinos are under huge pressure from poachers.
From the skies above Tsavo National Park, the Kenya Wildlife Service has been conducting its annual survey of elephant populations covering 48,000 square kilometers of land during the past few weeks.
"We brought poaching down around 2014, so we expect the population possibly to have started picking up," said Shadrack Ngene, head of the service's ecological monitoring.
It is a dangerous job. Last month, a Kenyan ranger was shot dead by poachers. The wildlife charity Thin Green Line estimates that about 100 rangers are killed in the line of duty every year.
China, the world's biggest ivory market, announced a ban in December on all ivory trade that takes effect by the end of 2017. It's been hailed as a game-changer by conservationists.