AP ES Ecological Succession

What does ecological succession refer to?


A series of predictable changes that occurs in a forest ecosystem

What are the two types of ecological succession mentioned?


Primary succession and secondary succession

What characterizes primary succession?


newly formed land, where nothing has grown before

What role do moss and lichen play in primary succession?


They colonize bare rock and break it down to form soil

How do moss and lichen contribute to soil formation?


Lichens can grow on bare rock. They produce acids that help break down the rock into smaller pieces, starting the process of soil formation, As moss and lichen grow and eventually die, they decompose. This adds organic material to the rock, enriching it and helping to create soil

What is the starting material for secondary succession?


An area with previously established soil

What types of disturbances can lead to secondary succession?


Wildfires, wind storms, or human disturbances

What are pioneer species in secondary succession?


Grasses, sedges, and wildflowers

How do mid-successional species differ from pioneer species?


They are larger, slower-growing, and require deeper, nutrient-rich soil

What are examples of mid-successional species?


Shrubs, bushes, and fast-growing trees like pine and cherry

What characteristics do late successional species share?


They tend to live longer than early successional species, allowing them to thrive in a more stable environment, large trees, grow bigger and can provide more shade and habitat for other organisms

Why does it take hundreds of years for late successional species to grow?


They need deep, nutrient-rich soil that takes time to develop

What is the difference between primary and secondary succession?


Primary succession starts from bare rock, while secondary succession starts from established soil

What events can lead to primary succession?


Volcanic eruptions or glacial retreats

How do moss and lichen contribute to the process of primary succession?


They chemically weather the rock (changing the rock into something new using chemicals) to release essential nutrients

What happens to the soil as pioneer species grow and die?


Their biomass adds organic matter, increasing soil richness and depth

What does the graph showing spruce trees per hectare indicate about their successional stage?


It helps determine whether spruce trees are early, mid, or late successional species

What are the basic steps of ecological succession?


1. Pioneer species colonize the area.

2. Soil depth and richness increase as pioneers grow and die.

3. Mid-successional species arrive as conditions improve.

4. Late successional species establish once soil is deep and nutrient-rich.

What are the characteristics of pioneer, mid-successional, and late successional species?


• Pioneer species:

• Fast-growing

• Wind or animal-dispersed

• Examples: moss, lichen, wildflowers

• Mid-successional species:

• Larger, slower-growing

• Require deeper, nutrient-rich soil

• Examples: shrubs, fast-growing trees

• Late successional species:

• Large, slow-growing trees

• Tolerant of shade

• Examples: maples, oaks