COMMUNITY CHANGE (SUCCESSION) Krebs chap. 21; pages ; 431 “the non-seasonal, directional and continuous pattern of colonization and extinction of species populations on a site”
PRIMARY SUCCESSION Mt. St. Helens pp Lake Michigan dunes pp Glacier Bay pp
SECONDARY SUCCESSION Krebs pp Abandoned fields Forest regrowth Abandoned lots
Mount St. Helens Vegetation recovery
Sand dune ecology Vegetation hummock Beach grass
Fig 21.11Profile of Lake Michigan sand dunes succession “SFT” – space-for-time substitution pastpresent
“Polyclimax” sand dune successions Fig
Krebs Fig Ice recession in Glacier Bay, Alaska, since
Alders and cottonwoods covering the hillsides 50 years
Spruce coming into the alder and cottonwood forest 100 years
Spruce and hemlock forest 250 years
Fig 21.9Change in soil-N Topsoil Mineral soil
1 year later Wildfire
Wind disturbance (“blowdowns”)
Opax Mountain Silvicultural Systems Trial (near Kamloops, BC)
Control burning
Control burn plot
Monitoring succession after fire