A secondary ecological succession will follow the destruction of the vegetation in an ecosystem, even if it has been completely destroyed in a major forest fire, provided that the soil has been left intact. Seeds brought into the area by wind or by animals, or seeds that were left below the soil before the disturbance, will take root and become the pioneer plants of the secondary succession. Herbaceous plant growth, such as grass, will begin to grow first, followed by bushes and the first-emerging trees, and lead ultimately to a restoration of the original ecosystem.Know More
A variety of mechanisms can trigger the secondary succession and affect the length of time of the restoration. Factors include the condition of the soil prior to the disturbance, trophic interactions and trade-offs between competitor and colonizer species.
A secondary succession occurring in a forest recovering from a major disturbance, such as a fire, will progress through four phases. The first is an establishment phase in which new seedlings from the first-appearance succession trees germinate in the soil left after the disturbance. In the thinning phase that comes next, these trees begin to compete for water, nutrients and light. The weaker trees are thinned out during this phase and new hardier shade-tolerant tree species begin to grow. The first-appearance trees begin to die off during the transition phase which follows. They are not able to reproduce because of the shaded areas they created, and the later-appearing shade-tolerant trees start to take over the forest. In the final steady state phase, the later shade-tolerant trees reproduce and grow under the forest canopy and the first-appearance trees, which were unable to reproduce and grow in the shade, are replaced.Learn more about Economics
Secondary economic activity, also known as the secondary sector of an economy, is the portion of the economy that is concerned with receiving raw materials and transforming them into serviceable items, properties or other goods. According to Matt Rosenberg at About.com, this means that secondary activity is most prominently found in areas such as manufacturing, processing and construction. For example, both heavy and light industry are integral parts of secondary economic activity.Full Answer >
In the investment community, the primary market refers to the market where securities are created, while the secondary market is the stock market where investors trade securities that they already own. While these terms sound similar, they refer to two very different things.Full Answer >
Primary and secondary consumers create the backbone of food chains: primary consumers, such as small bugs and insects, feed on plant matter and organic material while secondary consumers eat other animals. In addition to primary and secondary consumers, some food chains have a third level of consumers called tertiary consumers. These consumers are classified as carnivores, along with secondary consumers, and take the form of predatory birds and larger mammals.Full Answer >
Primary succession occurs in areas where no life has existed, whereas secondary succession happens when a disaster has devastated an area but has left some life in place. Succession begins with the colonization and activity of the pioneer species.Full Answer >