Cape urchins are integral to the kelp forest ecosystem. These spiny creatures graze on the kelp and other algae, keeping the growth in check and help maintain the balance of the Great African Sea Forests. This helps thin the thick dense canopy allowing sunlight to reach the lower levels of the forest floor.
This grazing also creates space for other organisms, promoting a diverse and healthy ecosystem, not allowing any one species to dominate the rocky surfaces. Urchins although can be seen climbing to the tops of the kelp stipes on calm days, seem to feed mostly from drift kelp which has broken off from the large canopy mass and sinks to the bottom where Urchins can access it much easier.
In this photo of a Cape sea urchin grazing on the kelp stipe you can see the clear star shaped mouth markings. The urchins 5 teeth meeting in the middle to take star chomps from the kelp.
The presence and behavior of urchins can indicate the overall health of the marine environment. However, overpopulation of urchins can signify an imbalance often caused by the decline of their natural predators. This is often indicated by signs of overgrazing, where large urchin barrens with tens or hundreds of urchins take over patches of the forest, not allowing any further kelp growth in that area. This can ultimately lead to complete devastation of kelp forests, turning vibrant underwater landscapes into “urchin barrens.” This often occurs when natural predators, such as sea otters and large urchin eating fish species decline due to over fishing or environmental changes.
Cape RADD continue to run research projects to monitor urchin populations and kelp health. Although the Great African Sea Forests are in a healthy state currently, understanding and knowing the warning signs of an ecological imbalance or environmental anomaly will help us with mitigating and managing potential threats to The Great Africa Sea Forests biodiversity.
Understanding the intricate relationship between Cape urchins and kelp forests is key to preserving these vital ecosystems. Conservation efforts and sustainable management practices will ensure that these underwater wonders continue to thrive, supporting diverse marine life and contributing to the overall health of our oceans.
Observing the world beneath the waves reveals the delicate interplay of species and the importance of each in maintaining ecological balance. The next time you think of marine conservation, remember the humble Cape urchin and its towering kelp forest home, a true testament to the complexity and beauty of our natural world.