As my beloved seedlings languished untouched on the display table, I improved my sales pitch: “Would you like a late-flowering thoroughwort to help migrating butterflies refuel? What about an aster that’s the only pollen source for some bee species?” But unlike the animals who would devour these...

The mountain lion known as P-47 survived fires, freeways and hostile ranchers. But in March, the 3-year-old big cat—tracked by California biologists since his kitten days—succumbed to a hidden hazard: an insidious form of food poisoning. Six anticoagulant compounds—chemicals used to kill rodents...