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All Life Transforms

Ecological Succession: Transformation of Communities Over Time



Primary Succession: Where No Plant Has Gone Before
Secondary Succession: Earth's Way to bandage Wounds

Individuals transform during personal lifespans. Species transform over species' lifespans, which may take millions of years. Recently we have come to understand that biological communities transform as well--as entire communities.

Ecological succession is the long-term process of natural vegetation communities changing. The community of plants in an area largely determines what animal life will be part of that community.

In most succession, the earliest growth prepares the way for the plants that follow.

Primary Succession:
Where no plant has gone before
Bare stone, but a hint of algae on its face and a bird dropping on top. Those, plus weathering, prepare the stone for lichens.

Stone colonized by lichens, which bit by bit dissolve the rock into nutrients. Life creates environment.

Stone covered with moss wherever light can reach. Lichens dead under moss, feeding moss.
A crevice in a boulder shows three stages of succession. Lichen, followed by mosses, and the makings of soil caught in the crevice. Seeds will follow.
On weathered wood, algae, lichens, and mosses show three stages in succession.
A fallen hemlock tree has become a nurse-log with tree saplings growing out of it, above the mosses that prepared the way.
Pines slowly climb a volcano cone after eruption. They've climbed about 10,000 years. This earthstar is the fruit of a fungus beneath volcanic cinders that helps prepare for green plants.
A seedling saltbush pioneers volcanic cinders Sagebrush and a single pine colonize the cinder barrens left from an eruption
Muskeg in the taiga was a lake long ago. Small lakes eventually are "swallowed" by land biomes. Lakes are slowly, gradually filled in by decaying vegetation and runoff fill, and eventually become peat bogs (muskeg).


Secondary Succession:
Earth's way to bandage wounds

Where land has been scarred by fire or disturbance such as plowing, it will soon be covered again with green. Secondary succession is incredibly fast compared to primary succession. Soil is already there, with nutrients. Seeds are already there, seeds of earlier occupants, windblown seeds of pioneer species which exploit disturbed soil (living bandages). After a fire, many seeds germinate in the fire's sudden heat that have waited years for the opportunity. Global warming is already changing the mix of species in temperate zones, and will continue.

Nature regards bare ground as a wound, and tries to heal this driveway with dandelions. This earth was torn up by truck tires six months ago. Pioneers have moved in. Garden weeds are just pioneers doing their jobs.
A birch tree begins to colonize a farm field from the edge in. Smaller deciduous trees, such as birch and aspen, are among the first to reclaim cleared land. A mountain riverbed is dotted with willows and seedlings. They will all be swept away by flood next summer. In the background, a logged slope is regenerating conifers.
Both secondary and primary succession are seen in this pond scene. In the background we see secondary succession: trees taking over a former ploughed field. The pond itself shows the shrinkage and shallowing caused by plant growth: this is primary succession.



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Explore Further in Transformation

Transformation over many lifetimes
Transformation Trickery
Transformation within the mind
  Metamorphosis Transformation in one lifetime
Death The final transformation
Return to Transformation Index


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