A new study at Tyson Research Center of artificial pond systems showed that dragonflies were the liaisons that connected aquatic to terrestrial ecosystems.
by Diana Lutz
An elementary school science activity asks children who have each been assigned a wetland plant or animal to connect themselves with string and tape to other “organisms” their assigned plant or animal interacts with in some way.
Once an ecosystem web has been created, the teacher describes an event that affects one “organism.” That “organism” tugs on its string. Other “organisms” that feel the tug then tug on their strings in turn.
The lesson is that every organism is important to the health and balance of a wetland and that every organism in the wetland is connected to every other organism in some way.
That’s more or less an article of faith among ecologists, but how true is it really? Ecologists rarely have the time or resources to test this foundational concept through experiment.
Now a summer-long study shows that purple loosestrife (Lythrum salicaria), a flowering invasive plant, triggers a chain of interactions that ultimately alters the diversity of zooplankton populations in artificial ponds.
The interactions cross traditional ecosystem boundaries, connecting aquatic to terrestrial systems on the wings of dragonflies that exploit, at different times in their lives, the resources of both the water and the land.
Diana Lutz is senior science editor in the university's Office of Public Affairs.
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