Herbivory is often perceived as a terrestrial phenomenon, only affecting plants and ecosystems on land. This is evident in the public, as well as the majority of literature on the topic. Herbivory of aquatic vascular plants has longly been considered of minor importance, as they did not take a predominant position in important food webs. However in recent years, there has been an increasing amount of research that shows herbivores play very important roles in the ecology of both freshwater and marine habitats. A recent study concluded that herbivores remove an average of 40-48% of plant biomass in aquatic habitats, compared to only 4-8% in terrestrial habitats. This is an extreme example of top-down regulation, that the herbivores have on many aquatic macrophytes and seagrasses, and has the ability to lead to entire ecosystem collapse. The effects of herbivory in terrestrial ecosystems is well-documented, and this has led to many management strategies put into place. A good example is the many herd-reduction strategies put in place to control white-tailed deer populations, in hopes to preserve plant biodiversity in many of our Provincial Parks. Herbivores have strong direct and indirect effects on aquatic plants and ecosystems. However, since these relationships are much less-documented and understood, management strategies are difficult to develop. Herbivore impacts are expected to increase under future climate change predictions, which will only further harm our aquatic ecosystems. It is definitely important to continue studying and classifying aquatic herbivores in order to better understand and predict their impacts on our beloved aquatic ecosystems.
Effects of herbivory on freshwater (a) and marine (b) aquatic ecosystems
References and Further Readings