2.5 Zonation, succession and change

• Changes in community along environmental gradient

• Factors: elevation, latitude, tidal level, soil, distance from water

• Measure biotic and abiotic factors along gradient

• Determine variables affecting species distribution

• Replacement of one community by another over time

• Due to biotic and abiotic variable changes

• Zonation: spatial; succession: temporal

• Each sere changes conditions for next community

• Competition until stable climax community reached

• Example: mosses → soil formation → larger plants

• On newly formed substratum without soil

• Examples: volcanic rock, retreating glaciers, wind-blown sand

• On bare soil with pre-existing community

• Examples: abandoned agriculture, post-fire forest

• Energy flow, productivity, species diversity, soil depth, nutrient cycling

• Depends on diversity and resilience

• Succession increases diversity → resilience and stability