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Hi friends, hope you're fine. From the
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Himalayas to the Andis mountain, as you
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see here, these extreme environments
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were once barren rocks. No soil, no
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water, no chance of life. How these
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barren rocks turned into a vibrant
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forest. This epic transformation is
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called ecological succession. In this
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video, we'll be discussing what is
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ecological succession with an example.
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the cerosier and the status of zerosier
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that is succession that is happening in
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dry habitats within 5 to 10 minutes.
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Let's begin with the definition.
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Ecological succession is a gradual
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replacement of one community with other
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in an area until forming a final stable
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climax community over a period of time.
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Now let us see how this works. The
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cerosier refers to succession that is
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happening on dry habitats that is water
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deficient environments like rocks or
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rocky mountains which is called as
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lithosier then deserts sandunes or bare
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rocks. It is called as sirak succession.
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Now let us see the stages to understand
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how these happens over a long period of
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time. So these are the different stages
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of zeros here. Let us break it down into
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each stage for better understanding.
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Starting with the first stage which is
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called the crust to lyken stage. So
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these are the lychans that first grow on
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this barren rocks. They are tolerant to
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extreme environments. They are the
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pioneer species to start the succession.
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These include risocarbon and many other
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species depending on the climate whether
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it is temperate or tropical. These
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lychans secrete acids that break down
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rocks into fine tiny particles and thus
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beginning the formation of first thin
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layer of soil. So the piner species or
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lychans first colonize this parent rocks
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to start the process of succession. So
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these are crusttos lyen that is firmly
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attached to the substratum or rock at
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many points it is attached firmly
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attached to the substrum as you see
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here. This is followed by folio lyken or
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folio stage. So this lyken as you see
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this lyken is not completely attached to
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There are leafike emergence or leaf like
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structures or thalus that is emerging
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out from the rock. Along with this folio
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lyken there will be fruicose lyken or
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bushy lychans like this. They retain
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more water and contribute more organic
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matter. Adding humus improves soil
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fertility allowing more animals or
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organisms to settle. The amount of soil
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increases at each stage along with
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humus. The third stage is the mos stage.
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There is enough soil for the mos pore to
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germinate. So this is polyrichum.
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Moses like polyricum spread across the
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surface forming a mat. And these mosses
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have risoids that penetrate deeper into
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and this absorbs more water and
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minerals. Many associated insects and
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other animals also comes to the side.
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Soil becomes thicker and more stable and
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this mo stage is replaced by herb and
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grass stage. As the soil gets deeper,
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these most plants are replaced by seeds
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of drought tolerant herbs arriving via
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wind or animals. These plants as you see
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here have deeper roots and enrich the
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soil with organic matter. Biod diversity
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begins to increase. Common species in
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tropical regions are grasses like aristo
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etc. So these are trot tolerant grasses.
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Now it is the turn of shrubs. Once the
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shrubs grows it shade out grasses so the
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growth of grasses diminishes and this
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produces tap roots deeper roots
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stabilizes the soil further
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provide more shelter and shade creating
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microhabitats for many animals. Soil
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moisture retention increases fertility
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improves as more organic matter is
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adding into the soil and the final stage
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is called the tree stage or the climax
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stage. Trees like fus in tropical
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regions whereas oak or oaks in temperate
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regions these are trot resistant species
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that begin to appear first. In the final
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stage a stable mature self- sustained
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forest forms that is suited to the local
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climate and this is the final stage of
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succession which is self- sustained and
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self-reliable which is rich in
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biodiversity and ecological balance. So
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for this process to happens for a
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primary section it takes more than
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thousand years. That is why a forest
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once destroyed it's very difficult to
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recreate this composition. Let us go
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through the definition once more. So
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ecological succession is a gradual
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replacement of one community that is
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starting from this lychans the pioneer
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species with other in an area until
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forming a final stable climax community
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which is self- sustained community over
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a period of time. The process is called
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as ecological succession. So here we
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have discussed the ecological succession
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that is happening on rocks or
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trihabitats which is called as cerosia.
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Hope you understand the process of
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ecological succession and the stages in
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cerosia. Take care, stay blessed. Thank
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you so much. You are with biology exams
