The Role Of Keystone Species in Maintaining Ecosystem Balance

Abstract 

Keystone species are crucial to their ecosystem because, without them, it would collapse. Researchers have found many different types of keystone species such as ecosystem engineers, predators, mutualists, and plants. This review explores how keystone species impact their ecosystems, how the ecosystems would be affected when the keystone species are removed and reintroduced. The key papers discussed in this are a review article discussing the impact of each category of keystone species, research about the maned wolf and solanum lycocarpum’s mutualistic relationship, an experiment to see how the removal of otters affect the ecosystem, a research paper exploring how the removal of beavers affected the biodiversity of the area, and research on how reintroduction of keystone species could be beneficial to the environment. These findings highlight a growing effort to understand global fauna more thoroughly in order to protect the ecosystem from further damage. Continued research could help to further rewilding efforts and climate action to reverse the decline of many species caused by human intervention

Introduction:

Keystone species are a vital part of the ecosystem. These important animals are species that other species in the ecosystem largely rely on, and without them the ecosystem would collapse. The term “keystone species” refers to an arch keystone which is a central stone at the top of the arch and it holds all the other stones of the arch in place. Without that stone, the whole arch would fall apart. There are many types of keystone species such as ecosystem engineers, mutualists, predators, and more. There have also been recently identified cultural keystone species which play a central role in the cultural identity, traditions and economy of a group of people. Recognizing the roles and impact of keystone species is crucial to better understand how to help combat climate change. This is because keystone species, also called “indicator species”, help indicate the health of the ecosystem they are part of. Overall, the aim of this review paper is to explore the different types of keystone species including predators, engineers, mutualists, and plants, and how the ecosystem would be impacted by their removal and reintroduction.

• Source 1: https://www.researchgate.net/publication/382959521_Keystone_Species_and_Their_Impact_on_the_Ecosystem_Current_Trends 

  This review article titled “Keystone species and their impact on the ecosystem: Current trends” by Swati Mishra explores how four primary categories of keystone species maintain the health of the ecosystem. First are keystone predators who regulate the population of the prey which helps prevent the prey’s species from becoming overpopulated and mitigates overgrazing. An example of this is the grey wolf who has helped vegetation recovery and increased biodiversity by controlling the elk population in Yellowstone National Park. Second are mutualists who are a part of a relationship between themselves and another species in which both species benefit, which is also known as a mutualistic relationship. For example, bees are mutualists because they have a mutualistic relationship with the plants they pollinate. This relationship gives food to the bees while helping the plants reproduce. Next are engineers who help construct new habitats by altering the environment. One example of a keystone engineer are the beavers in North America who build dams. This creates wetlands which provide habitats for aquatic species and boosts biodiversity. The last type of keystone species are keystone plants who provide habitats and resources which benefit a wide variety of species. For example, mangroves create nurseries for aquatic species and protect shorelines from erosion. In conclusion, keystone species are crucial to the balance of ecosystems because they maintain biodiversity, regulate populations, and enhance ecosystem resilience.

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  Source 2: https://www.academia.edu/26464311/Diet_of_the_maned_wolf_Chrysocyon_brachyurus_and_its_role_in_seed_dispersal_on_a_cattle_ranch_in_Brazil

  A research paper titled “Diet of the maned wolf (Chrysocyon brachyurus) and its role in seed dispersal on a cattle ranch in Brazil” by Eliana F. Santos, Eleonore Z. Setz, and Nivar Gobbi, examines the relationship between the keystone mutualist, the maned wolf, and plants in the solanaceae family such as solanum lycocarpum. The experiment consisted of monthly collections of the maned wolf’s scat to determine its feeding habits. After being collected, the scat was then examined for articles such as scales, feathers, bones, claws, and seeds. To study the effect the maned wolf’s gut has on the solanum lycocarpum germination studies were conducted on the seeds found in the scat. The seeds were sown in 2 plastic trays and observed over a 30 day period to see if germination was possible. The results showed that solanum lycocarpum were found in 90% of the scats meaning maned wolves are a crucial disperser of the seed. They also showed that these seeds have higher and faster germination rates after passing through the wolf’s digestive tract. The data shows the maned wolf and solanum lycocarpum have a mutualistic relationship; because the wolf helps spread its seeds and increase their chance of germination, it acts as a keystone mutualist in this ecosystem.

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  Source 3: https://www.elakhaalliance.org/wp-content/uploads/2020/10/1974-Estes-and-Palmisano-Science.pdf

  Another research paper by James A. Estes and John F. Palmisano titled “Sea Otters: Their Role in Structuring Nearshore Communities” studies and compares the ecosystem of western Aleutian Islands with and without a population of sea otters. In the islands without sea otters it was found that there was destruction of vegetation such as kelp and sea grass because of the overgrazing and overpopulation of sea urchins. On the contrary, at the island with sea otters, there was an abundance of kelp and a much smaller population of sea urchins. Kelp beds are crucial to these islands because they shelter their shores from destructive waves. From this Estes and Palmisano conclude that having a population of sea otters helps preserve the vegetation of the coastal ecosystem. This makes sea otters a keystone predator because they regulate the population of their prey, sea urchins, which keeps the flora such as kelp alive, benefitting the whole ecosystem.

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  Source 4: https://www.sierraforestlegacy.org/Resources/Conservation/SierraNevadaWildlife/North%20American%20Beaver/Beaver-Wright_Jones_and_Flecker_2002.pdf

  Next, A research paper by Justin P. Wright, Clive G. Jones, and Alexander S. Flacker titled “An ecosystem engineer, the beaver, increases species richness at the landscape scale” studies the importance of a keystone engineer, the beaver in the Huntington Wildlife Forest. Data was taken from undisturbed areas of the forest to set a baseline for biodiversity in the area. Next, the biodiversity of areas of land that have been modified by beavers was recorded. The results showed that there was a big difference in the types of species between the forested land and the beaver-modified land and that the total number of species in the region increases by 33% in beaver-modified land when compared to forested land. This shows promising evidence that the beaver’s ecosystem engineering has a direct beneficial impact on the biodiversity of the area. However, more studies would have to be done to prove that the beavers who lived in the Huntington Wildlife Forest are a keystone species, for example, finding species that can only live on the beaver-modified plots.

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  Source 5: https://cales.arizona.edu/research/redsquirrel/res_pdf/HaleKoprowski2018RestEcolKeystoneSppReintroductions.pdf

  Finally, a review article titled “Ecosystem-level effects of keystone species reintroduction: a literature review” by Sarah L Hale and John L Koprowski explores how reintroducing keystone species affects the ecosystem. This was done by compiling many research papers and comparing them with one another. Three research papers were about the reintroduction of the beaver. Overall, these papers all found that rewilding resumed many of the beaver’s keystone functions such as influencing hydrological processes. A lot about keystone rewilding is unknown, such as if the species can fully resume its role, but much research shows there is a lag in ecosystem-level responses. This indicates that this delay might not have been detected in many past studies. For example, studies have been done on the reintroduction of prairie dogs who usually cycle nutrients throughout the soil. It was found that there was no influence on the micromammals and flora, but the experiment was conducted in a short time, so the effects of the prairie dog might have not affected them yet. Additionally, it was found that mammals had been mainly focused on in these experiments and most of the experiments were conducted in the United States. In order to have the most accurate data, experimentation with keystone species should be diversified in terms of location and species.

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  Conclusion:

  Overall, a keystone species is a species that the ecosystem relies on. There are four primary types of keystone species: predators, engineers, mutualists, and plants each with their own way of maintaining ecological balance. Some examples of this include preventing overgrazing, increasing biodiversity, and scattering seeds. Keystone species are crucial to its ecosystem and the removal of them would result in drastic ecological damage. Studies such as the ones on the maned wolf, the sea otters, and the beavers show how these keystone species are crucial to their environment. Finally, reintroduction of keystone species has shown promising results to improve the conditions of the ecosystem, but future research should be done on a wider range of species in more locations around the world.

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  References (APA Format):

  Swati Mishra. (2024). Keystone species and their impact on the ecosystem: current trends. Journal of Ecology and Conservation.

   

  Eliana F. Santos., et al. (2003). Diet of the maned wolf (Chrysocyon brachyurus) and its role in seed dispersal on a cattle ranch in Brazil. Journal of Zoology, The Zoological Society of London, 260, 203–208.

   

  James A. Estes., et al. (1974). Sea Otters: Their Role in Structuring Nearshore Communities. Science, New Series, 185(4156), 1058-1060.

   

  Justin P. Wright., et al. (2002). An ecosystem engineer, the beaver, increases species richness at the landscape scale. Oecologia, 132, 96–101.

   

  Sarah L. Hale., et al. (2018). Ecosystem-level effects of keystone species reintroduction: a literature review. The Journal of the Society for Ecological Restoration, 26(3), 439-445.