Question

crustonse lichens form a pioneer species" - Discuss​

Answer 1

Answer:

Pioneer species are hardy species which are the first to colonize barren environments or previously biodiverse steady-state ecosystems that have been disrupted, such as by fire.

Some lichens grow on rocks without soil, so may be among the first of life forms, and break down the rocks into soil for plants.

Since some uncolonized land may have thin, poor quality soils with few nutrients, pioneer species are often hardy plants with adaptations such as long roots, root nodes containing nitrogen-fixing bacteria, and leaves that employ transpiration. Note that they are often photosynthetic plants, as no other source of energy (such as other species) except light energy is often available in the early stages of succession, thus making it less likely for a pioneer species to be non-photosynthetic.

The plants that are often pioneer species also tend to be wind-pollinated rather than insect-pollinated, as insects are unlikely to be present in the usually barren conditions in which pioneer species grow; however, pioneer species tend to reproduce asexually altogether, as the extreme or barren conditions present make it more favourable to reproduce asexually in order to increase reproductive success rather than invest energy into sexual reproduction. Pioneer species will die creating plant litter, and break down as "leaf mold" after some time, making new soil for secondary succession (see below), and nutrients for small fish and aquatic plants in adjacent bodies of water.