When looking around outside, many people see reasons to worry about the environment. Often what they notice are the effects of pollution and climate change, which can be harmful to people, wildlife, and the ecosystems where they live. Understanding the condition of all living and non-living things in an ecosystem is important for maintaining a healthy environment. But collecting information on every element in an ecosystem takes time and effort and is not always possible. Luckily, the United States National Park Service scientists know that collecting data on the condition of one species, called an indicator species, can reveal a lot about the well-being of other species in an ecosystem. Based on what they learn from observing and studying indicator species, park managers can make decisions about restoring plants, using chemicals, and posting signs about fishing rules. In Indiana Dunes National Park (Indiana, United States), researchers rely on frogs as indicator species.