Ecological Succession
= how living organisms change a landscape
= how an ecological environment evolves over time
KEY TERMS:
Ecological Succession
Sere
Pioneer Community
Climax Community
= the process of species structure and community change in an ecosystem over time
starts with bare land/rock to climax community, taking place over a long period of time
taking place over a long period of time:
population > community > habitat > ecosystem
= a full succession from bare rock to forest
each community in the succession = seral stage/community
results in a climax community
= the community of autotrophs like algae and lichens that start proliferating (multiplying/increasing in number) in an area
can grow in a place where there is no organic matter in the soil
invade the area to a certain extent, until other organisms can live there
= the biotic community that had reached dynamic balance between all of the species and the physical environment
without human disturbance
all organisms and community structures within that area is balanced, constant/consistent for a long period of time
food chains are stable
PRIMARY SUCCESION
Pioneer Stages
- Lichens
- Small annual plants, lichens
- Perennial herbs, grasses
- Grasses, shrubs, shade-intolerant trees (intermediate stages)
- Shade-tolerant trees (Climax Community)
- Bare Rock
nothing but abiotic components
very hostile
invasion of cynobacteria, algae, photoautotrophs
(don't depend on other species)
no soil, therefore they thrive first
convert energy into organic matter, and as organic matter increases, attract more lichens as environment is less hostile
when they die, their remains turn into organic matter that becomes soil
no soil, therefore cannot store/sustain H2O
soil accumulates for small plants to grow and small animals/insects
increased organic matter, biomass in soil
stay at rock surface and capture external energy
better cycling of nutrients
annual species
- fast accumulation of organic matter
- grow, flower, produce seeds/fruits before dying off all in 1 season
soil can now sustain water for shrubs and trees
trees occupying space - long term survival (perennials)
seeds dispersed by animals
increased soil content can sustain larger plants and trees
sufficient soil to retain moisture
highest amount of soil when succession reaches the dynamic balance of biotic and abiotic factors in a CLIMAX COMMUNITY
tall, large, woody trees
increased animal species diversity over time
shade tolerant trees = effectively capture a small amount of light, meaning that it flourishes on the ground
= an area that has not been occupied previously, the process of initial invasion and then progression from one biotic community to the next
SECONDARY SUCCESSION
= when an area has been cleared by fire/ human activity
plants and animals from the surrounding ecosystem may gradually reinvade the area through several distinctive stages
- Fire / any form on damage or loss (year 0)
- Pioneer Species
- Intermediate Species (5-150 years) grasses, shrubs, pines, young oak and hickory
- Climax Community (150+ years)
- mature oak and hickory forest
was going through primary succession but was disturbed by a event
Herbaceous plants / annual plants
but some soil is still there, some seeds and plants still survived
Grasses and perennials
sufficient soil already present, therefore can sustain these plants
CHANGES DURING SUCCESSION
types of animals & plants differ in their characteristics
early stages - plants are annuals
later stages - succeeded by herbaceous perennials then woody perennials
plant species change from 1 serial community to another, due to sunlight/ nutrients/ competition
lichens might not be able to survive when there's no bare land, (all trees) so they have to survive on tree trunks
the type of small animals/insects present highly depends on the plant species presences
always associated with increase in biomass and soil becomes deeper
diversity of plants and animals tend to increase: greatest number of plant and animal species will be present at the climax community