The differences in substrate-building capabilities between species are often minute, but they allow each species to stabilize the soil within different stable states, or layers, in the marsh. Some species prefer elevations at or below mean sea level; others prefer higher elevations that are less often inundated.
"Interestingly, our models and surveys show that plants make trade-offs when colonizing within their preferential ranges," Marani said. "Entire sections of a species' vegetation patch often are located above the elevation needed for its maximum biomass productivity." This gives it a bit of margin to compensate for external fluctuations, such as the rates of relative sea level rise or sediment availability.
"Essentially," he said, "the species hedges its bet by trading maximum productivity for greater long-term stability."
Scientists have long known that biodiversity plays an important role in a marsh ecosystem's long-term health and survival, "but this paper provides a clear causal link suggesting how and why," he said. "The take-home message is that the more species you have colonizing different levels within a marsh, the more resilient to abrupt change the marsh as a whole will be."
He said that marshes in which an invasive species, such as cordgrass, has pushed out other species will be less resilient to climatic changes.
|Contact: Tim Lucas|