Why does primary succession occur

These pioneer species are hardy species that can withstand harsh conditions. If you've found an issue with this question, please let us know.

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Your Infringement Notice may be forwarded to the party that made the content available or to third parties such as ChillingEffects. Thus, if you are not sure content located on or linked-to by the Website infringes your copyright, you should consider first contacting an attorney. Hanley Rd, Suite St. Louis, MO Subject optional. Email address: Your name:. Possible Answers: None of these. Correct answer: An environment lacking plant and animal life. Explanation : Primary succession is the colonizing of a new environment that lacks organisms and plant life.

Report an Error. Which of the following best describes when secondary succession occurs? Possible Answers: A previously inhabited environment. Correct answer: A previously inhabited environment. Explanation : Secondary succession can be described as the colonization of a habitat that once supported plant and animal life but was abandoned due to ecological disturbance.

Possible Answers: Secondary succession. Pioneering succession. Primary succession. Correct answer: Secondary succession. Explanation : Primary succession occurs in an environment without previous life, or a barren habitat. Observe the young hardwoods growing up beneath the still living pines.

The raspberry thickets growing in the sun lit forest sections beneath the gaps in the canopy generated by wind-thrown trees. Raspberry plants require sunlight to grow and thrive. Beneath the dense shade canopy particularly of the red pines but also beneath the dense stands of oaks, there is not sufficient sunlight for the raspberry's survival.

However, in any place in which there has been a tree fall the raspberry canes have proliferated into dense thickets. You may observe this successional consequence of macro-ecosystem change within the red pine stand and all along the more open sections of the trail. Within these raspberry thickets, by the way, are dense growths of hardwood seedlings.

The raspberry plants are generating a protected "nursery" for these seedlings and are preventing a major browser of tree seedlings the white tailed deer from eating and destroying the young trees. By providing these trees a shaded haven in which to grow the raspberry plants are setting up the future tree canopy which will extensively shade the future forest floor and consequently prevent the future growth of more raspberry plants!

The succession "garden" plot. This plot was established in April, please see the series of photographs on the "Succession Garden Plot" page. The initial plant community that was established within the boundaries of this plot was made up of those species that could tolerate the periodic mowing that "controlled" this "grass" ecosystem.

Soon, though, other plant species became established as a consequence of the removal of the stress of mowing. Over time, the increased shading of the soil surface and the increased moisture retention of the undisturbed soil-litter interface allowed an even greater diversity of plants to grow and thrive in the Succession Garden.

Eventually, taller, woody plants became established which shaded out the sun-loving weed community. In the coming years we expect tree seedlings to grow up within the Succession Garden and slowly establish a new section of the forest. Ecological succession is a force of nature.

What is primary succession? What is the difference between primary and secondary succession? Ecological succession occurs because? See all questions in Ecological Succession. Impact of this question views around the world. You can reuse this answer Creative Commons License. Large, low intensity disturbances, such as plowing in conventional agriculture, result in moderate amounts of succession, where species can survive in the soil and quickly recolonize areas after a disturbance.

Early successional communities are those that establish themselves relatively quickly after disturbance, while late successional communities are those that establish themselves much later. Classic Perspectives of Succession. Figure 1: Chronosequences are often used to study succession. A Typical chronosequence for sand dune succession. Figure 2: Two contrasting views of succession.

A The super-organism concept, where groups of species are tightly associated, and are supplanted by other groups of tightly associated species. Patterns and Mechanisms of Succession. Plant reestablishment 15 years after the debris avalanche at Mount St. Figure 4: Succession after glacier retreat. Figure 5: Keever's observed pattern of succession in North Carolina agricultural old fields.

Recent Research on Succession. Recently, ecologists have been developing mathematical models to better characterize and predict successional changes. For example, The Resource Ratio Hypothesis, proposed by David Tilman , models successional shifts in plant communities based on the assumption that succession is driven by a tradeoff in competition for nutrients in early succession, and for light in late succession.

Other researchers, such as Henry Horn have used transition matrix models and Markovian models to measure rates of succession and predict the outcomes of succession. Figure 6: Plant diversity increases throughout succession. Fields were last plowed in While the process of succession has been studied by ecologists since the turn of the 20th century, it is still very much a dynamic field of study today.

Multiple, complex mechanisms can all interact to result in predictable patterns of change in communities over time. Recently, ecologists have used principles of succession to inform the applied ecological fields of Restoration Ecology and Invasion Biology.

References and Recommended Reading Bazzaz, F. Odum, E. The Strategy of Ecosystem Development. Science , Reiners, W. Plant diversity in a chronosequence at Glacier Bay, Alaska. Ecology 52, Article History Close. Share Cancel. Revoke Cancel. Keywords Keywords for this Article. Save Cancel. Flag Inappropriate The Content is: Objectionable. Flag Content Cancel. Email your Friend. Submit Cancel. This content is currently under construction.

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