Nature and Biodiversity
What is Nature?
"Nature" and "biodiversity" are words commonly used today in media and our daily conversations, but what do they actually mean?
Nature is everything that we see around us. Everything that humans have not created, from rivers to wind, to mammals, to each grain of sand - all of these things are considered nature. Humans, too, are a part of Nature, and Nature has provided us with all we have needed to survive and flourish for millennia. Before recent advances in technology, our species had to have deep connections with and great respect for Nature in order to survive. However, presently, many of us are suffering from a lack of connection to Nature and a lack of respect for the non-human world. Unfortunately, the negative repercussions of this way of thinking can already been seen all over the world as landscapes become exploited and climate change progresses. To restore our connection and harmony with Nature we need a revolution of thought, a new renaissance period where we all go back to our ancient roots —roots that Indigenous people's have always been advocating— of living responsibly on, of caring for and of respecting the land. One of the first steps to reawakening our respect for Nature is to learn more about her and to find our place within her.
Nature is an interconnected chain of reliance and influence. Each organism, grain of soil and drop of precipitation influences the system. For example, a drop of rain waters a butternut tree which grows to become a nesting site for birds and a restaurant for squirrels. However, the butternut tree is not only reliant on water, but also the nutrients in the soil below, the temperature of the seasons and the sun far, far above. No being is isolated in Nature. We are all connected. This connection means that any action to alter Nature has complex repercussions. If we plant a willow shrub on an eroding riverbank it will help to stabilize it by holding the soil in place with its roots. This then invites a Jack Pine to grow who will outlive the planter of the willow and provide a home and food for generations of our non-human kin. If we terraform and harden surfaces on our properties, it will influence local water absorption which may cause increased flooding and have lasting harmful effects our lakes. To preserve and care for Nature we must think about the repercussions of our actions and how they extend beyond humans.
Food chains in Nature
The interconnectedness mentioned above is why food chains exist. A food chain is a series of relationships between living beings based on consumption — many species rely on each other to survive, both directly and indirectly.
Below is an example of a food chain: the hawk eats the bird who ate the mosquito which fed on nectar and aquatic plant matter. The frog (tadpole) also eats mosquitos and then itself is eaten by a fish, hawk, or fox etc.
Food chains lie in a delicate balance with each species filling a special niche (function). Thus, if we remove plankton from the system (for example due to a septic system failure caused by inappropriate tank management and pollute our lake), we jeopardize the integrity of the food chain because plankton are at its base. Therefore, we must always remember that each native species is important to maintaining the integrity, health and balance of Nature.
Energy pyramids - the natural flow of energy
Food chains/webs also help to move energy through the environment. We can conceptualize this movement of energy as a pyramid with Producers on the bottom followed by Primary Consumers, Secondary Consumers, and Tertiary Consumers on top. As you move from one level to the next, energy is transferred with about 10% of total energy from the previous level being consumed/captured by the next (the excess energy is lost as heat). Typically, we assume that all energy (100%) enters the system through the Producers (plants and photosynthetic organisms capture this energy from the sun). Of that 100%, 10% is captured/consumed by Primary Consumers, 1% (of that 10%) by Secondary Consumers and 0.1% (of that 1%) by Tertiary Consumers. (As an aside, this is why it makes more economic sense to raise and consume Primary Consumers, like cattle, than it does Tertiary Consumers, like wolves - it would be expensive and waste a lot of energy per unit meat produced).
A detailed example and explanation: Let's start from the base of the pyramid and make our way to the top. Energy from sunlight is absorbed by plants (Producers) and used to grow. Plants are then consumed by other organisms, like insects and animals, who are classified as Primary Consumers. Many of these animals are prey species to omnivores or carnivores who then eat them (Secondary Consumers). At the top of the pyramid we have the apex predators (humans part of this level) which have no predators themselves, but consume animals from the levels below. In addition to the pyramid, organisms in each layer ultimately parish and feed the decomposers which convert decaying matter into nutrients. These nutrients are now more accessible to plants, and the cycle begins again.
In short, as one organism consumes another, energy moves up the pyramid until it reaches the top. This means that Secondary and Tertiary Consumers are much more efficient at obtaining energy than Primary Consumers (they typically gain more energy per gram of matter consumed). This fact also explains why Primary Consumers spend a lot more time in the actual act of eating than animals above them in the energy pyramid. Ultimately, the system is circular — each step feeds back into itself and relies on the energy levels below.
What happens when you remove or add species to a habitat?
As previously mentioned each organism plays an important role in keeping an ecosystem healthy and balanced. The interactions between any two given species ultimately affect on other species in the ecosystem due to the interconnected nature of food webs. Therefore, if organisms are removed from or added to the system it can have surprisingly drastic impacts on the functioning of the entire system. A healthy ecosystem is like a well greased machine, each component, each species, is a vital piece to keeping the machine running. If we remove a species, we remove a gear, if we add an invasive species, we add an incorrect component. Both inhibit the machine from run optimally and cause further damage. Below we will discuss some more detailed examples of what happens if you remove or add species.
Trophic cascade - When top predators (Tertiary Consumers) are removed from a system it can have radical effects on other organisms and ecosystem dynamics because they are no longer controlling prey species populations. For example, the removal of top predators in North America, like wolves, has had negative impacts on woody plant populations because ungulate species (deer, moose, etc) are no longer controlled. This has resulted in higher densities of ungulates and increased amounts of grazing (it is also theorised to have had negative impacts on American Ginseng populations - click here to learn more). Over several years their heighten populations have significantly changed forest lifecycles, altered historical habitats and reduced biodiversity in certain regions.
Removing non-apex species - The removal non-apex animals can also have negative consequences on an ecosystem. For example, let's remove mosquitos from an area by spraying a pesticide. Mosquito larvae are a very important part of the food chain as they are a prolific food source for fish fry and many aquatic insects. Adult mosquitos provide important pollination services and in fact, some species of native orchid are heavily pollinated by mosquitos. No pollination of such orchids means low levels of reproduction and or reduced genetic diversity. Adult mosquitos are also important food sources for predatory insects, like dragonflies, and other animals like birds and bats. Thus, removing mosquitos can negatively impact numerous of species and ultimately the entire system.
Introducing non-native species - Not only can removing a species influence the food chain, but adding a species can also have similarly negative impacts. For example, if the invasive species Phragmites (a European reed expanding its range into the Land Between region) is introduced to a system, it displaces native reed species. This then impacts the Food Web because every organism that relied on native reeds must now adjust to the new species (Phrag) or leave the area in order to survive. (If you are interested in learning more about Phragmites and how to safely remove it please visit our Phrag Fighters Community Science Page.)
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What is biodiversity?
Biodiversity is the number of different species (usually native species) that are living in an area. Every single species of fungi, plant, insect, bird and mammal that you see in your backyard are contributing to its biodiversity. "Diversity" being the important root word, means variation. Therefore, biodiversity is not the population of one species, but rather is the presence of multiple species. For example, if a forest has only maple trees, one small predator (with a very large population), one species of bird and two asters, it is not biodiverse compared to a forest with many different species of small predator (even if in smaller individual populations than the above example), birds, plants, etc. Having biodiversity allows the overall ecosystem to be healthy and more resilient.
Why is biodiversity important?
Having a biodiverse ecosystem or property helps to maintain Nature in a healthy state by keeping the system resilient to change. For example, you only have one predator in a system, say foxes, and then a new disease enters the population and 60% of the foxes die. Since they were the only predator their reduction you would result in increased rodent populations, like rabbits. With rabbit populations no longer being controlled by foxes, their numbers would greatly increase and they would consume more vegetation, putting negative pressure on plant species and all the organisms that rely on them for food and/or shelter. When this happens it can reduce the populations other species, which starts the cycle again (this is called a negative feedback loop). Contrastingly, in a biodiverse system, this negative feedback loop is inhibited because there are multiple species helping to fill a single niche. For example, there would be multiple predators (hawks, wolves etc), so a reduction in the population of only foxes would have a limited impact on rodent suppression.
With higher amounts of biodiversity, organisms are better able to adapt to change because they have a larger support system than locations with few species. Another way to think about it is like a 10 piece puzzle versus 1000 piece puzzle. If you damage one of the 10 pieces it greatly affects the picture and structural integrity of the puzzle, versus if the same thing happens with one piece out of 1000 (the impact is smaller).
Written by: Fallon Hayes, Digital Communications and Education Lead
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Works Cited
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