Environmental stress model of community organization Relative importance

  • Slides: 15
Download presentation
Environmental stress model of community organization

Environmental stress model of community organization

Relative importance of interspecific interaction Environmental stress model competition predation stress alleviation diversity of

Relative importance of interspecific interaction Environmental stress model competition predation stress alleviation diversity of basal species associational defenses Environmental stress Bruno, Stachowicz & Bertness (2003)

Richness of primary space holders Richness of secondary space holders (sessile and mobile associated

Richness of primary space holders Richness of secondary space holders (sessile and mobile associated species) Overall richness / diversity Bruno, Stachowicz & Bertness (2003) Trends in Ecology and Evolution 18: 119 -125 Scrosati & Heaven (2007) Marine Ecology Progress Series 342: 1 -14

Test of ESM on the NW Atlantic coast Vertical gradient Horizontal gradient Desiccation -

Test of ESM on the NW Atlantic coast Vertical gradient Horizontal gradient Desiccation - Temperature Irradiance - Osmotic potential Wave exposure - Ice scour

- Gulf of St. Lawrence coast - Atlantic coast Nova Scotia New England

- Gulf of St. Lawrence coast - Atlantic coast Nova Scotia New England

Methods Environmental stress gradients Vertical gradient (3 levels) High - Mid - Low intertidal

Methods Environmental stress gradients Vertical gradient (3 levels) High - Mid - Low intertidal Upper limit determined using barnacles Horizontal gradient (2 -3 levels) Gulf (wave + ice): Sheltered - Exposed Atlantic (wave): Sheltered - Intermediate - Exposed dynamometers (wave exposure) cages (ice scour)

Methods Richness, Diversity & Evenness • Summer • Abundance of all seaweeds and invertebrates

Methods Richness, Diversity & Evenness • Summer • Abundance of all seaweeds and invertebrates (% cover) • 25 cm x 25 cm quadrats (n = 20 per Elevation x Exposure combination) Richness Sr of species Diversity (Simpson's index) 1 - D = 1 - (pi) Evenness (Simpson's index) E = (D * S)-1

Results 38 seaweeds - 29 invertebrates

Results 38 seaweeds - 29 invertebrates

Results - Richness across Elevation Means ± SE Gulf of St. Lawrence 2 =

Results - Richness across Elevation Means ± SE Gulf of St. Lawrence 2 = 39 % Elevation Atlantic 2 = 41 % Elevation

Results - Richness across Exposure Means ± SE Gulf of St. Lawrence 2 =

Results - Richness across Exposure Means ± SE Gulf of St. Lawrence 2 = 10 % Wave - Ice Exposure Atlantic 2 = 12 % Wave Exposure

Test of ESM on the NE Atlantic coast

Test of ESM on the NE Atlantic coast

Test of ESM on the NE Atlantic coast (Helgoland Island) Helgoland's elevation gradient (wave-sheltered

Test of ESM on the NE Atlantic coast (Helgoland Island) Helgoland's elevation gradient (wave-sheltered shores)

Overall richness and diversity (Helgoland Island) Zwerschke, Bollen, Molis & Scrosati (2013) Helgoland Marine

Overall richness and diversity (Helgoland Island) Zwerschke, Bollen, Molis & Scrosati (2013) Helgoland Marine Research 67: 663 -674

Environmental stress model (ESM) Predation Hypothesis Intermediate Disturbance Hypothesis RICHNESS SESSILE SPECIES (PRIMARY SPACE

Environmental stress model (ESM) Predation Hypothesis Intermediate Disturbance Hypothesis RICHNESS SESSILE SPECIES (PRIMARY SPACE HOLDERS) Menge & Sutherland (1987, American Naturalist 130: 730 -757)