The cascading connections between land and water are too numerous to count. The lines between the two get blurry. Standing on the water’s edge, we can see and feel the difference between water and land, but the ecological relationships are constantly flowing back and forth. The voracious dragonfly is a perfect example of trophic cascades. A trophic cascade is the ecological term for how species interact within a food web or how a prey’s prey can impact the density and behavior of another level of the food web. In this drama-filled soap opera plot, hungry fish, predatory dragonflies, butterflies, and flowers are locked in a balancing act. With the right balance, fish can help grow flowers!
Hine’s emerald dragonfly nymph, a threatened and/or endangered species once found in parts of Ohio. Ryan Hagerty/USFWS, Public Domain, https://www.fws.gov/media/hines-emerald-dragonfly-nymph
Studies have found that there are more flowers present near ponds with fish compared to ponds that do not have fish. Let’s jump into this drama with the dragonfly’s life cycle from egg, larva (nymph) to adult. Most species of female dragonfly dip their eggs directly into the water, where they will hatch and become a larva, molt, and grow. Depending on the species, this process can take several weeks or several years! During this time, the baby dragonflies are on the lookout for fish… to eat! Dragon babies don’t mess around, but larger fish can prey on dragonfly eggs and larvae. The dragonflies that do survive and eventually emerge as adults then go on to cause even more havoc as incredible insect predators hunting mosquitoes, flies, bees, butterflies, moths, and even other dragonflies. Unchecked, these hungry hunters can actually cause the pollinator population in an area to drop enough to have an impact on the flowers. By eating dragonflies and their larvae, that’s how fish grow flowers!
Monarch butterfly collecting nectar from native butterfly weed. USFWS, Public Domain, https://www.fws.gov/media/monarch-butterfly-1
Ohio River Foundation is committed to educating students about the ecology of our river system and the amazing connections between land and water. Every fall and spring, we take thousands of students into local waterways to find and study important bioindicators like dragonfly nymphs. Our River Explorer field trip puts kids into the water to practice real, hands-on field research methods, using science equipment and techniques.
4-6th Grade Students from Pleasant Ridge Montessori identify fish and macroinvertebrates in Banklick Creek in October.
We are also committed to habitat restoration through invasive species removal and planting native trees and wildflowers. Ohio River Foundation is a regional leader in tree and live stake installations in Greater Cincinnati, with more than 10,000 installed in each of the last 3 years. Trees provide numerous benefits, including cleaning the air, purifying water, providing habitat for wildlife, reducing the urban heat island effect, and contributing to a healthy local economy. They also help regulate the water cycle, prevent soil erosion, and combat climate change. Furthermore, trees offer social and health benefits, such as reducing stress and promoting community interaction.
We’re launching the largest pollinator restoration project in our region, creating and restoring more than 1,000 acres of native habitat, benefiting the monarch butterfly and other pollinator species that are threatened, protected, or in decline due to habitat loss.
As the monarch butterfly is considered for federal protection, this project holds huge potential to reverse this species’ decline. The value of pollinators to overall ecological health and food production is immeasurable.
Healthy pollinators mean healthy ecosystems and a stronger food supply for all of us. Learn more and support the project here.