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Population ecologists study the changes in numbers and location of organisms growing in the same area at the same time. A population ecologist studying dandelions might ask questions such as: How many dandelions are there? Is the number of dandelions increasing or decreasing? Where are they found? But dandelions also interact with other species of plants and animals--that is, they live in plant and animal communities. For example, insect species may feed on the dandelion leaves, roots, or seeds; grass species may compete with dandelions for soil nutrients, and fungi and bacteria may decompose dead dandelions. Community ecologists study the interaction of different organisms such as these. And finally, a third type of ecologist, the ecosystem scientist, studies the interaction of living things with their non-living environment. For example, an ecosystem scientist might ask how nitrogen, carbon, and water cycle between soil, living things, and the atmosphere. Or, he or she might wonder how nutrients, light, and water control the productivity of plants in a wetland, forest, or other ecosystem. Population and community ecologists and ecosystem scientists hope that by learning about the natural world, they can help find solutions for environmental problems. One of the biggest environmental problems facing North America is the introduction of invasive species (also called introduced, alien, or exotic species) that later become weeds or pests.
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Ecology