How herbivores help the reef
There are many types of animals that live within the Great Barrier Reef Marine Park, each with its own unique role to the health and longevity of the reef. From sea stars to sharks or rays, turtles, fish or even vast gardens of corals, each individual organism plays their own vital role its their ecosystem. One of those very important roles belongs to the herbivores. A herbivore is a animal that feeds only on plants; they are not predatory towards other animals nor do they hunt other animals, but instead survive of nutrients provided by plants only. And they are helping the reef big time.
All animals on the reef serve a purpose; each and everyone of them is involved in the balancing act that it takes to maintain a healthy ecosystem. However, one such part of that ecosystem may be overlooked and that is the herbivore. While the herbivore's role may be hard to see and therefore may seem less impressive, they are doing more for the reef than what many people may notice.
Species such as parrotfish, rabbitfish, surgeonfish, damselfish, and unicornfish all play a vital role in coral health, as they are all plant eaters. Coral health is very directly related to reef health, as they are the building blocks of any reefs. Herbivorous species remove algae and seaweed from the reef's ecosystem, which if left to their own devices, can affect the overall health of a reef, strangling it. With too much algae or seaweed floating around the reef, covering healthy corals, reef health will decline. While both algae and other plant life are important to the reef overall (namely in coral health), the vegetarian fish stop the algae from growing in excess, which can stunt the growth of new coral. As they eat, they also clean, which will help maintain the balancing act of the Great Barrier Reef Marine Park.
The algae and seaweed eating species act as composters or lawnmowers, keeping everything neat and tidy and allowing the life of the reef to move forward. In fact, if you're snorkelling or scuba diving and you listen carefully, you can hear the munching and crunching of the herbivores as they eat and clean the reef, demonstrating a very direct link in reef health and herbivorous species.