Every organism lives in perfect balance with its environment. What happens in the surrounding environment directly or indirectly influences the life and development of the organism. While some thrived in the ecosystem, different external factors – natural or manmade – often harm the organism’s life. This gradually leads to its endangerment and eventually, extinction. Some species are considered very significant in the ecosystem, that when they are removed from it, critical consequences in the environment will occur leading to further reduction of species diversity and significant changes in community dynamics. Such species are commonly referred to as “keystone species”. Keystone species are species of organisms that need to be protected from endangerment because of their crucial role in the ecosystem to maintain community structure and continued existence of other species.
KEYSTONE SPECIES
The concept of keystone species was first coined by Robert T. Paine, a professor of zoology at the University of Washington, in 1969, in order to explain his observations and experiments on the relationship between intertidal invertebrates. While he was conducting experimental manipulations in the rocky shoreline communities on the Pacific coast in Washington, Paine discovered that the removal of the carnivorous starfish Pisaster ochraceus, the primary predator in the aforementioned local ecosystem, brought about to the local extinctions of several benthic invertebrates and algae, such as a species of mussel, Mytilus californianus. In his paper entitled “Food Web Complexity and Species Diversity”, he argued that “the species composition and physical appearance were greatly modified by the activities of a single native species high in the food web. Paine subsequently formally introduced the concept and term “keystone species” in his paper entitled “A Note on Trophic Complexity and Community Stability”. He stated: “These individual populations are the keystone of the community’s structure, and the integrity of the community and its unaltered persistence through time, that is, stability, are determined by their activities and abundance.” Paine’s field experiments and coinage of the term “keystone species” have been extensively reproduced in many texts and propagated to the scientific community. Because of this, many follow-up definitions have been presented. One classic definition is by Daily et al. stating that “keystone species are those whose removal from a community would precipitate a further reduction in species diversity or produce other significant changes in community structure and dynamics”. Another definition that focused on its disproportionate effect relative to abundance is stated by Power et al.: “Keystone species are species whose impact on its community or ecosystem is large and disproportionately large relative to its abundance.” Moreover, because of the introduction of the concept, a range of species were identified as keystone species all throughout the years. In the marine ecosystems, for example, the sea otter (Enhydra lutris) was found to control sea urchin populations along the Aleutian Islands. It was discovered that sea otters protect kelp forests from damage by consuming sea urchins. The removal of sea otters therefore caused the release of sea urchins from predation pressure, increasing its abundance and the reduction of kelps due to the sea urchins’ rapid consumption. In the freshwater ecosystems, beavers (Castor Canadensis) were found to influence plant and animal community composition and richness in North America. Beavers alter the edges of riparian areas by cutting down older trees to build their dams, thus allowing younger trees to take their place. These dams have shown to be beneficial to various species such as several amphibians, salmon, and song birds. In the terrestrial ecosystems, pocket gophers (Geomyidae) were believed to keep North American prairie soils in a condition that could support higher plant diversity. Keystone species are organisms that are critical to the environment when removed. There are a lot of organisms considered as keystone species. While many of them are thriving in the ecosystem, some keystone species are endangered and in the brink of extinction.
ENDANGERED KEYSTONE SPECIES
Because the exact number of species on Earth is ambiguous, it is often difficult to accurately quantify the number of species becoming or close to becoming extinct. However, according to the World Wildlife Fund (WWF), scientists approximate between 10,000 and 100,000 species cease to exist every year because of habitat loss, resource depletion, climate change, and other factors. Some of this species that are endangered or in the danger of extinction are keystone species. These species include bees and sea otters, among others.
Bees are flying insects of the order Hymenoptera and clade Anthophila that are recognized for their critical part in pollination and for producing honey and beeswax. Bees are considered as keystone species for their natural insect-mediated pollination that they provide in order for several plants to reproduce. In fact, bees are responsible for the pollination of about 250,000 plant species. Without insect pollination, about three-fourths of the crops human kind eat would suffer some decrease in productivity. Bees are the predominant and most economically important group of pollinators in most geographical regions. However, many species of bees are suffering in the present and are threatened by many environmental factors, including lack of natural habitats and increased exposure to man-made chemicals. Due to this fact, bees, which are important keystone species, are considered to be declining globally.
Not only bees, sea otters also suffer from endangerment. As mentioned in the previous paragraphs, sea otters are identified as keystone species for their predatory capabilities on sea urchins that feed on kelp forests. Kelp forest ecosystems support a variety of marine species, from the small sea stars to sharks. Apart from this, sea otters also help in restoring aquatic carbon-fighting plants, which helps in fighting climate change.
If keystone species would be extinct, ecosystems would possibly collapse and extinction rates of other organisms will dramatically increase. Simply put, the endangerment of these species is a critical problem that needs to be solved. Therefore, several solutions were proposed, including protection programs of the said species.
PROTECTION OF KEYSTONE SPECIES
Protecting keystone species is a main priority for conservationists. Where a keystone species has been identified, efforts to protect it also will help protect the other species in delicately balanced ecosystems. There are government and non-government organizations that aim to conserve endangered species, particularly keystone species.
The National Resources Defense Council, a non-profit international advocacy group, aspires to prioritize in protecting keystone species by pursuing science-based management of these animals and taking the government to court when necessary. They also planned for improved management strategies and more protected wildlife corridors.
More generally, acts where passed in order to protect endangered species. In the United States, the Endangered Species Act (ESA) was passed in 1973 in order to protect those plant and animal species that are at risk of becoming extinct. The US Fish and Wildlife Service (FWS) is responsible for listing, delisting, and reclassifying the species protected by the ESA. The ESA outlines a number of protective measures that are designed to preserve species that have been listed as Endangered or Threatened. These measures include restrictions on hunting, transporting, and trading the species.
In the Philippines, the Republic Act No. 9147, also known as the “Wildlife Resources Conservation and Protection Act”, was passed to “conserve the country’s wildlife resources and their habitats for sustainability”. The Department of Environment and Natural Resources (DENR) has jurisdiction over all terrestrial plant and animal species while the Department of Agriculture (DA) has jurisdiction over all declared aquatic critical habitats.
CONCLUSION
Keystone species are significant species that when removed from the ecosystem, can create imbalance and cause drastic consequences, such as a shift in community dynamics and extinction of other organisms. There are several known keystone species, such as the sea otters, beavers, and pocket gophers. Furthermore, there are other predators considered as keystone species, including tiger sharks and jaguars. However due to external factors in the environment and man-made actions, some of the keystone species have become endangered. Some known endangered species are the bees and the sea otters. Bees are recognized as keystone species for their ability to pollinate, and in turn, the sustainability of many plant species. Sea otters, on one hand, preys on sea urchins which is a main cause of the decline of kelp forests, an important ecosystem for many marine organisms; thus, they are considered as keystone species. The endangerment of these species and keystone species in general, poses a critical problem that needs to be solved. Therefore, government agencies and non-profit organizations established some acts and programs focused in the protection of the aforementioned species.
