What did Jane Lubchenco discover about snail densities in tide pools?

Jane Lubchenco's research highlighted the relationship between snail densities in tide pools and algal species richness. She discovered that algal species richness is highest at intermediate densities of snails. This finding is significant because it reveals a balance in the ecological interactions between herbivores (like snails) and their food sources (algae).

At low densities of snails, algae can dominate the space and grow extensively, but with the absence of enough grazing pressure from snails, certain algal species can outcompete others, leading to lower diversity. Conversely, at very high densities of snails, excessive grazing can lead to overconsumption of algae, reducing the availability of food resources and subsequently decreasing species richness. The peak in species richness at intermediate densities suggests a situation where grazing is enough to keep dominant species in check, allowing a diverse array of algal species to coexist.

This optimal interaction emphasizes the role of herbivores in maintaining ecological balance and biodiversity within marine environments, particularly in fluctuating conditions such as those found in tide pools.