In the dead of night on February 15, gunshots blasted the guards into action in India’s Kaziranga National Park. Rangers stationed in a nearby camp quickly spread out, searching for the shooters under the light of a nearly full moon – to no avail.

For weeks, the primatologists had followed a group of Grauer’s gorillas over rugged terrain – hacking through dense rainforest; following knife-edged ravines; and crossing a nearly impenetrable mountainous landscape in the eastern part of the Democratic Republic of the Congo (DRC).

MEXICO CITY – On bad days, you can smell the stench from a mile away, drifting over a nowhere sprawl of highways and office parks.

The legal commercial exotic animal trade is a booming enterprise that ships ornamental fish, mammals, birds, reptiles and amphibians around the world. These pets, livestock and other animals can carry unexpected infectious diseases from their homelands. If these non-native species escape or are released to the wild, they can create epidemics among susceptible endemic wildlife.

Frank Morton has been breeding lettuce since the 1980s. His company offers 114 varieties, among them Outredgeous, which last year became the first plant that NASA astronauts grew and ate in space. For nearly 20 years, Morton’s work was limited only by his imagination and by how many different kinds of lettuce he could get his hands on. But in the early 2000s, he started noticing more and more lettuces were patented, meaning he would not be able to use them for breeding.

AGADEZ, Niger — The world dismisses them as economic migrants. The law treats them as criminals who show up at a nation’s borders uninvited. Prayers alone protect them on the journey across the merciless Sahara.

The United Nations Environment Program is highlighting the battle by Iraqi forces to reclaim Mosul from the Islamic State as the latest instance in the complex but very real linkage between military conflicts around the world and extreme environmental degradation.

“By 2050 the world urban population is expected to nearly double, making urbanization one of the 21st century’s most transformative trends.” -Draft “Quito Declaration on Sustainable Cities and Human Settlements for All,” September 2016