any of the first plants to take root in an area cleared of vegetation during the process of succession. Depending on the area, the “pioneers” could be mosses, lichens, grasses, etc. Some of the pioneer trees that start in an area have to be strong or robust enough to compete with grasses and other pioneer plants. And since there are no other trees to shade them, they must thrive in full sunlight. Some examples of pioneer trees (depending on the ecosystem) might include cedars, pines, sumac, and sassafras.
An animal or plant species that establishes itself in an environment where it did not exist, or a species that colonizes an area during an early successional phase i.e, aspen establishing itself within an idle field.
A plant species that colonizes habitat that was previously unoccupied or sparsely occupied by that species. In the successive settlement of an area by plant species, such as after a fire, pioneer species lead the process.
A pioneer species is a plant species which colonizes previously uncolonized land, usually leading to ecological succession. Since uncolonised land usually has thin, poor quality soils with few nutrients pioneer species are typically very hardy plants, with adaptions such as long roots, root nodes containing nitrogen fixing bacteria, and leaves which reduce transpiration.