Impact on Coral Reefs
By foraging on a variety of sponges, hawksbills change the species composition and distribution of sponges in coral reef ecosystems. By removing sponges from reefs, hawksbills allow other species, like coral to colonize and grow. Without hawksbills, sponges are likely to dominate reef communities, further limiting the growth of coral and modifying the very structure of coral reef ecosystems.
Maintaining a Balanced Food Web
Leatherbacks obtain their energy and nutritional needs from a small, gelatinous source, jellyfish. They have been known to consume up to 440 pounds of jellyfish each day. Leatherbacks play a pivotal ecological role as a top jellyfish predator. Declines in leatherback turtle population could have repercussions for jellyfish population control. The increase in jellyfish is already providing detrimental to recovery of fish stocks since jellyfish prey on fish eggs and larvae.
Sea turtles are a keystone species that play vital roles in the health, structure and complex functioning of marine and coastal habitats.
Maintaining Habitat
Green sea turtle helps to maintain healthy seagrass beds by foraging on seagrass just a few centimeters from the bottom of the blades, allowing older, upper portions of blades to float away. Without a constant grazing, seagrass beds overgrow and obstruct currents, share the bottom, and older portions of seagrass beds tend to overgrow with microorganism, algae, invertebrates, and fungi. When green sea turtles graze, they increase the productivity and nutrient content of seagrass blades.
Providing Food for Fish
By carrying around barnacles, algae, and other organisms known as epibionts, sea turtles provide a food source for fish and shrimp. Other organisms establish cleaning stations in which sea turtles offer a meal to eager fish and shrimp. Some species obtain their diet strictly from epibionts found on sea turtles. Without this food source, certain species of fish and shrimp might be forced to develop other less successful methods to obtain food.
Improving Nesting Beaches
By providing a concentrated source of high quality nutrients, sea turtles improve their nesting beaches. Nutrients such as nitrogen, phosphorus, and potassium are partially provided to the ecosystem by unhatched turtle eggs. These vital nutrients allow for the continued growth of vegetation and stabilization of beaches and dunes. Plant growth not only helps to stabilize the shoreline, but it also provides food for a variety of plant eating animals.
Photo by Scott Eanes
Photo by Scott Eanes
Photo by Linda Reinhold