rabies: a widespread, viral, potentially fatal infection spread through the bite of certain warm-blooded animals that attacks the nervous system.
radio-tracking collar: a collar with a transmitter that emits radio waves that can be tracked by a researcher with a radio receiver and directional antenna. When data are collected and transmitted over a distance, the process is called telemetry.
range: the area in which an organism may travel in its lifetime. Range also refers to the geographic distribution of a particular species.
rapid assessment (of an ecosystem or area): a quick scientific survey or count that helps measure local biodiversity to obtain maximum knowledge of the life in a selected ecosystem or area, ideally with minimum time and resources.
recycling: the series of activities in which discarded materials are collected, sorted, processed and converted into new materials for use in the production of new products.
refuge: a safe place.
regime shift (in the ocean): a rapid modification of ecosystem organization and dynamics with prolonged consequences. In many cases, regime shifts involve multiple factors and internal feedbacks.
reintroduce: to return members of a species to their historical range. This strategy is sometimes used when a species has become locally extinct or if its population is threatened.
remote sensing: the determination of a quantity by detecting it from a distance e.g., the use of satellite-borne instruments to determine the location and amount of resources on Earth's surface.
renewable energy: energy obtained from sources that are essentially inexhaustible. Renewable sources of energy include wind, wood and the sun.
resilient: the ability to recover readily from adversity, depression or other challenges.
runoff: water from rain, snow melt or irrigation that flows over the ground surface and returns to streams and can collect pollutants from air or land and carry them to the receiving waters.
Russian roulette: a stunt in which an individual spins the cylinder of a revolver loaded with only one bullet and then points the muzzle at his/her head and pulls the trigger; any very risky situation.