Plants and animals from other areas invade, crowd out native species. To Protect These Priceless Lands. If these resources are lost, we will lose more than our natural heritage. Beyond the immediate value of existing plants and animals, this delicate system provides us with many ecological services, such as food, clothing, medicine, shelter, recreation, and wildlife habitat. Trees and other plants protect the air we breathe, filtering out pollutants.
Insects devour decaying plant and animal materials.
Plants prevent soil erosion and flooding, and keep our water clean and drinkable. Communities of plants hold in reserve irreplaceable genetic information that scientists can draw upon in search of new medicines and improved agriculture. However, in order to protect the parks, we must understand them. This understanding can only be achieved through science. Biologists and ecologists study individual plants, animals, and insects and their habitats to learn more about each species and, ultimately, about their value to humanity.