Chapter 20 outline Eco

Concept 20.1: Changes in species diversity and composition during succession.
Concept 20.2: Increases in biomass, primary production, respiration, and nutrient retention during succession.
Concept 20.3: Mechanisms driving ecological succession: facilitation, tolerance, and inhibition.
Concept 20.4: Community stability is influenced by lack of disturbance or resistance/resilience against disturbance.

Succession: The process of change in plant, animal, and microbial communities following a disturbance or new substrate creation.
Primary Succession: Takes place on newly exposed geological substrates.
Secondary Succession: Occurs after disturbances that leave the soil intact.
Pioneer Community: Initial organisms to colonize after a disturbance.
Climax Community: Community that remains stable until disturbed.
- Clements' View: Succession influenced by species interactions leading to predictable climax communities.
- Gleason's View: Communities arise from individual species distributions along environmental gradients, leading to unpredictable outcomes.

Reiners et al. (1971): Investigated plant diversity in succession over a chronosequence of sites; found diversity tends to increase over time.
Buma et al. (2019): Challenged prior views, observed diversity remained stable or decreased; highlighted importance of initial species.

Oosting (1942): Documented increased woody plant richness with succession.
Johnston and Odum (1956): Noted parallel increase in bird diversity with woody plant diversity.

Newly stripped intertidal boulders undergo rapid recolonization:
- First colonizers are green algae and barnacles, followed by red algae over time.
- Succession periods vary: 1,500 years in Glacier Bay, 150 years in Piedmont, and 1.5 years for intertidal boulders.

Fisher et al. (1982): Studied rapid succession in Sycamore Creek, Arizona; noted rapid changes in algae and invertebrates after flooding.
Diatoms and algae quickly recolonize; many macroinvertebrates survive as aerial adults.

Concept 20.1: Community changes during succession; species diversity and composition.
Concept 20.2: Ecosystem changes include increases in biomass, primary production, respiration, and nutrient retention.

Hawaiian Islands: Formed over hot spots, exhibit varied soil feature changes (Hedin et al., 2003):
- Organic matter and nitrogen initially increase, then decrease; phosphorus shows no consistent pattern.

In Sycamore Creek, biomass increases rapidly post-flooding, with slower accumulation thereafter.
Changes reflect on species composition, diversity, and ecosystem structure/function.

Facilitation Model (Clements): Species modify the environment, making it suitable for later species.
Tolerance Model (Connell and Slatyer): Initial colonizers are not restricted to pioneer species; climax occurs when tolerant species are exhausted.
Inhibition Model: Early species modify the environment to inhibit both early and later species; dominance ends with long-lived species.

Sousa's Study: Found early species had lower survivorship due to herbivory, supporting inhibition model.
Turner's Research: Found facilitation in surfgrass recruitment by middle successional algae.

Stability: Defined as absence of change; can result from lack of disturbance, resistance, or resilience.
Park Grass Experiment: Studied effects of fertilizer over 150 years; no new species introduced; observed community variability as a measure of stability.
Valett et al. (1994): Studied Sycamore Creek, finding stable hydrologic linkages promote nitrogen supply and ecosystem recovery.

Restoration ecology: Focus on restoring ecosystems to biodiversity levels; manipulates succession for goals.
Testing Restoration Methods:
- Addition of forest litter and seeding in mining tailings improved biodiversity (Dias et al., 2012).
- Use of bird perches to boost seed diversity (Shiels and Walker, 2003).
- Recontouring abandoned roads accelerated restoration significantly compared to non-treated roads (Lloyd et al., 2013).

Community and ecosystem changes during succession.
Mechanisms of succession that apply to various ecosystems.
The importance of understanding stability in ecological contexts involving disturbances and restoration.