A team studies primary succession on the volcanic island of Surtsey, formed in 1963. Plots of equal area are surveyed in 1970, 1985, 2000, and 2015. The team counts plant species richness and percent ground cover. Soil organic matter is measured.
Which trend is predicted as primary succession proceeds?
- A
Species richness decreases as soil forms
- B
Soil organic matter is highest in 1970
- Ccheck_circle
Both species richness and soil organic matter increase over time
- D
Ground cover is independent of time
Explanation
On bare volcanic rock, pioneer species (lichens, mosses) accumulate organic matter. As soil develops, more species can colonize, increasing both richness and organic matter over decades.