In
ecology
Ecology () is the study of the relationships between living organisms, including humans, and their physical environment. Ecology considers organisms at the individual, population, community, ecosystem, and biosphere level. Ecology overl ...
, allogenic succession is
succession driven by the
abiotic component
In biology and ecology, abiotic components or abiotic factors are non-living chemical and physical parts of the environment that affect living organisms and the functioning of ecosystems. Abiotic factors and the phenomena associated with them un ...
s of an
ecosystem
An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syste ...
.
In contrast,
autogenic succession "Auto-" meaning self or same, and "-genic" meaning producing or causing. Autogenic succession refers to ecological succession driven by biotic factors within an ecosystem and although the mechanisms of autogenic succession have long been debated, ...
is driven by the
biotic component
An ecosystem (or ecological system) consists of all the organisms and the physical environment with which they interact. These biotic and abiotic components are linked together through nutrient cycles and energy flows. Energy enters the syst ...
s of the ecosystem.
An allogenic succession can be brought about in a number of ways which can include:
*
Volcanic eruptions
Several types of volcanic eruptions—during which lava, tephra (ash, lapilli, volcanic bombs and volcanic blocks), and assorted gases are expelled from a volcanic vent or fissure—have been distinguished by volcanologists. These are often ...
*Meteor or comet strike
*Flooding
*Drought
*Earthquakes
*
Non-anthropogenic climate change
Allogenic succession can happen on a time scale that is proportionate with the disturbance. For example, allogenic succession that is the result of
non-anthropogenic climate change can happen over thousands of years.
Example
The majority of
Salt Marsh
A salt marsh or saltmarsh, also known as a coastal salt marsh or a tidal marsh, is a coastal ecosystem in the upper coastal intertidal zone between land and open saltwater or brackish water that is regularly flooded by the tides. It is domin ...
development comes from allogenic succession. The constant exposure to water in the
intertidal zone causes the soil of a salt marsh to change over time. This results in sedimentation and nutrient buildup that also slowly raises the level of the land. What started as a sandy soil with a slightly high
pH level
In chemistry, pH (), historically denoting "potential of hydrogen" (or "power of hydrogen"), is a scale used to specify the acidity or basicity of an aqueous solution. Acidic solutions (solutions with higher concentrations of ions) are me ...
, eventually becomes a loamy soil with a more neutral pH level. During this period, the soil-salinity will also change by starting low and eventually rising to higher levels from continued seawater exposure.
Glacier foreland
The region between the current leading edge of the glacier and the moraines of latest maximum is called glacier foreland or glacier forefield. In the Alps this maximum was in 1850 and since then the region has become ice free due to deglaciation ...
s are another example of ecosystems that form from
autogenic but also partly allogenic succession.
The importance of which is estimated to be higher in earlier successional stages, regarding rock formations, slope angles and soil composition.
See also
*
References
Ecological succession
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