Nature's Architects
Introduction
The environment is a product of the animals it hosts, shaped and built by species that are known as nature’s architects. While all animals impact their environments to some extent, only a select few keystone species leave lasting marks. Creatures, such as beavers and termites, modify their landscapes significantly, making them essential to the health and stability of the ecosystems.
What Are Ecosystem Engineers?
Ecosystem engineers are species that creates, changes, and maintains habitats, thus influencing the biodiversity and ecological stability of their habitats. Their capacity to alter environments to extreme extents leads to changes in resource availability and the local biological community. Some of the most well known species include: beavers, woodpeckers, and parrotfish (Odum, 1971; Lawton & Jones, 1995).
Figure 1: An Eurasian beaver, one of the major ecosystem engineers in marsh and wetlands. (Source: Shutterstock)
The term was first coined in 1994 by Jones et al, where these species are described to be organisms that cause a biologically mediated habitat modification. Although the semantics of the term are being debated, it is still widely accepted and used by scientists and ecologists.
Ecosystem engineers can be categorised into either allogenic or autogenic engineers (Jones et al., 1994). Allogenic engineers are species that alter the biophysical environment by mechanically transforming living and non-living materials from one form to another. For instance, woodpeckers create holes in trees, which are used by other birds to nest in. On the other hand, autogenic engineers affect the environment by modifying their own physical structures. Examples of autogenic engineers are usually plants.
Case Study 1: Beavers
Beavers are commonly associated with logs in the water and partially chewed trees. Both the Eurasian beaver (Castor fiber) and the North American beaver (Castor canadensis) play crucial roles to their respective wetlands through management of ecosystem structures, water resources, and vegetation (Brazier et al., 2021).
Beavers cut down trees and build a series of dams on rivers. The dams are typically constructed of logs, branches, rocks, mud, and leaves. They back up water and form beaver ponds, which are essentially deep pools of water filled with sediment, nutrients, plants, and wildlife. These ponds provide access to food for the beavers as it covers their food sources as well as act as a safer medium for travel. Using their dams, beavers help slow down the flow of water, thus leading to less erosion and flooding as peak flows downstream are reduced. Additionally, as extensions to the beaver ponds, these creatures often excavate shallow canals to further build their food resources for access and transport.
Figure 2: Diagram highlights the differences between streams with and without beavers under the same conditions. (Source: Vox)
As a result of the beaver dams, more habitat is created for the populations in the area. Due to the waters slowing down, it will cover additional areas and create more wetlands. Research shows that the growth of diverse vegetation for animal and human intake increases by over 33% in beaver wetlands (Wright et al., 2002). With around one-fourth of the species in the area reliant on beaver activity for resources and habitat, it is clear that a sizable portion of the ecosystem would suffer from diminishing numbers of this rodent species.
Besides that, beaver dams improve the quality of water. Rainwater runoff carries pollutants into the rivers, potentially destroying aquatic ecosystems. However, mineral-rich sediments deposited in the wetlands are able to filter out and metabolize toxins using bacterial populations, cleaning the water that flows downstream. Moreover, beaver wetlands aid in preventing the accumulation of greenhouse gases via carbon absorption. Reports found that beaver wetlands hold 470,000 tonnes of carbon each year, which leads to less atmospheric carbon.
Since then, there have been several reintroduction projects involving beavers, such as in Scotland and England, to alleviate flooding in specific areas (Kemp et al., 2012; Scottish Wildlife Trust, 2021).
Case Study 2: Corals
Deep-sea corals are the ecosystem engineers of the oceans. Corals are marine invertebrates, consisting of individual units called polyps. These coral polyps secrete calcium carbonate, which forms their exoskeletons. For the majority, the colours of corals are dependent on the proteins they have, whereas some result from symbiotic algae.
Figure 3: Deep-sea coral reefs that aid in the protection of marine biodiversity. (Source: Getty Images)
The corals take calcium and carbonate ions from the seawater to build massive geological structures – coral reefs – over long periods of time. Coral reefs serve as a habitat for a large variety of organisms and species. For example, many tiny organisms tend to hide out in the coral reefs to avoid falling prey to predators. Aside from that, the reef supplies nutrients and resources to aquatic organisms. Deep-sea corals consume decaying cells of microscopic organisms, otherwise known as marine snow. Waste is excreted and ingested as nutrients by algae on the surface. By recycling waste into usable nutrients, the waters remain nutrient-rich to support life underwater. In summary, the coral reefs are crucial to maintaining biodiversity in the ocean considering how they occupy less than 1% of space yet support around 25% of marine species. This is evidently seen in the Great Barrier Reef in Australia, which hosts around 1500 species of fish and 400 species of coral alongside other aquatic organisms.
Despite the importance of coral reefs to both marine life and humans, coral reefs are currently threatened by various factors, primarily caused by human activity. Coral bleaching, ocean acidification, and pollution has caused coral reefs to die, in turn leaving lasting harmful impacts on marine ecosystems.
Biomimicry: Human Takes On Ecosystem Engineering
Since nature has tested and proven numerous strategies, humans have begun to draw from the strategies of ecosystem engineers and copy those techniques. Biomimicry is the practice of emulating nature in its systems, materials, and technologies. The concept uses nature as a model to observe and recreate certain biological processes, structures, and systems to solve challenges in a sustainable manner.
Some examples of biomimicry pertaining to ecosystem engineers include beaver dam analogues (BDA). Beaver dam analogues are human-made structures built with natural materials to recreate the effect of beaver dams. Generally, these structures are temporarily installed for stream restoration and maintenance of riparian systems.
Conclusion
Ecosystem engineers are indispensable to their habitats in terms of maintaining and improving their environments, ecosystems and ecological relationships with other organisms in the area. Losing these ecosystem engineers could mean the loss of biodiversity and higher risks of instability in the ecosystem, tipping the delicate balance in these ecosystems. Hence, to restore the environments, people are undoubtedly looking towards reintroduction of these species and biomimicry methods to imitate the impact of these species.
Article prepared by: Estelle Sia Yu Qi, MBIOS R&D Director 24/25
If you enjoyed this article, do sign up to become a part of our MBIOS family and receive our monthly newsletter along with many more resources in the link below.
References
Brazier, R. E., Puttock, A., Graham, H. A., Auster, R. E., Davies, K. H., & Brown, C. M. L. (2021). Beaver: Nature's ecosystem engineers. WIREs. Water, 8(1), e1494. https://doi.org/10.1002/wat2.1494
Emmi Palenbaum. (2024, February 5). Deep-sea corals: Ecosystem engineers - Coastal Conservation League. Coastal Conservation League; Coastal Conservation League. https://coastalconservationleague.org/blog/deep-sea-corals-ecosystem-engineers/
Jones, C. G., Lawton, J. H., & Shachak, M. (1994). Organisms as Ecosystem Engineers. Oikos, 69(3), 373–386. https://doi.org/10.2307/3545850
Luberto, E. (2023). Leave it to Beaver… Dam Analogs (U.S. National Park Service). Www.nps.gov. https://www.nps.gov/articles/000/bdas.htm
Rubin-Thomas, C., & Blackledge, S. (2023, April 3). Beavers are “ecosystem engineers” and fight climate change, too. Environment America. https://environmentamerica.org/articles/beavers-are-ecosystem-engineers-and-fight-climate-change-too/
University of Helsinki. (2018, August 29). Beavers have an impact on the climate. ScienceDaily. Retrieved December 4, 2024 from www.sciencedaily.com/releases/2018/08/180829115119.htm
Wright JP, Jones CG, Flecker AS. An ecosystem engineer, the beaver, increases species richness at the landscape scale. Oecologia. 2002 Jun;132(1):96-101. doi: 10.1007/s00442-002-0929-1. Epub 2002 Jun 1. PMID: 28547281.
Comentarios