Question

homework - ecological succession
when an ecosystem moves from primary to secondary succession of plant species, which most likely declines?
rate of erosion
plant diversity
animal activity
thickness of soil

Explanation:

• Rate of erosion: In primary succession, there is little to no soil or vegetation to hold the land. As succession progresses to secondary (where there is already some soil and remnants of an ecosystem), more plants grow. Plants' roots bind the soil, reducing erosion. So the rate of erosion is likely to decline.
• Plant diversity: Secondary succession generally has more plant diversity than the early stages of primary succession as there is already a foundation (soil, some plant/seed remnants) for more species to establish.
• Animal activity: More plants (in secondary succession compared to early primary) usually mean more food and habitat for animals, so animal activity is likely to increase.
• Thickness of soil: In primary succession, soil is being formed (e.g., by lichens breaking down rock and organic matter accumulation). In secondary succession, soil is already present and often gets thicker over time as decomposition and plant - root activity continue.

Answer:

rate of erosion