From the smallest microorganisms to the largest mammals, nature’s intricate balance during autumn ensures
resilience and renewal of the environment for the coming year.
Autumn is a season between summer and winter featuring a gradual temperature decrease. The Northern
Hemisphere will reach autumn around September 22 or 23, while the Southern Hemisphere is around March
20 or 21. Significant temperatures only occur between places from middle to high latitudes. Those around the
equator typically experience little temperature change throughout the year. Autumn symbolizes a time of
harvest associated with abundance and prosperity, the climax of a growth cycle, maturity, and adulthood in life.
There are numerous changes in living organisms that evolve to preserve the delicacy and health of their local
ecosystems, such as tiny unseen microbes shifting their metabolic rate, prickly hedgehogs scurrying
underground into their soil-nourishing tunnels, and massive bears crouching peacefully within their hibernating
caves. From microscopic to monumental, each creature follows the rhythm of autumn’s change, working in
harmony with the altering ecosystem.
Microorganisms like bacteria and fungi facilitate decomposition within the soil. Carbon sequestration is the
process of capturing and storing carbon dioxide in the air into the dirt. Most microbes can make carbon into
usable energy sources for themselves and modify carbon-based compounds into soil organic matter (SOM) for
soil structure. In sequestering carbon, microbes reduce the greenhouse effect, which is considered an ongoing
environmental concern, as carbon dioxide is absorbed from the atmosphere and is put into long-term storage
in soil cavities. Increased carbon content in soil improves plant growth because its roots can accomplish more
uptake to compensate for the leaves pressured into doing carbon fixation the whole time. Greater SOM makes
water retention better, thereby resisting erosion in extreme weather events like drought, floods, or heavy
rainfall.
A close friend of carbon dioxide, oxygen, can also assimilate into the soil through microbes, forming soil
aggregation. Because many bacteria synthesize special polysaccharides (a large complex sugar), soil particles
clump and stick together into aggregates that assist with soil porosity and integrity. The polysaccharide is like
the adhesive sugar filaments interior of a roasted marshmallow. Well-structured soil generally has more
air-filled holes to sufficiently aerate the soil. It allows plants to root deeper and access more nutrients and
water. Porous, oxygen-fed soil, generates better drainage and reduces the risk of waterlogging which can kill
decomposers and create anaerobic regions underground. As water moves downward, the soil also gathers
more moisture to provide a reservoir for organisms during dry periods.
Plant phenology refers to the adjustments and changes plants bring forth. Leaf senescence is a process when
plants with green leaves age, degrade, and eventually fall off the plant structure. The chlorophyll (green
pigment that uses sunlight as a source of energy) disintegrates, producing no more sugars through
photosynthesis, causing the leaves to turn yellow, orange or red before they die on the ground. This process is
crucial for recycling nutrients because when leaves fall and decompose, essential elements like nitrogen,
phosphorus, and carbon re-enter the soil which enhances soil fertility and prepares for growth in the upcoming
year. Leaf litter also provides shelter and food for various insects like ladybugs and rove beetles, which in turn
convert leaves into nutrients they need. Insects, which are vital food sources for secondary consumers,
establish the foundation for energy production in the food web.
Some plants go into a state of dormancy as they temporarily stop growth, development, and metabolism. This
is winter dormancy. After plants shed their leaves in autumn, they halt growth until new leaves sprout in the
spring to continue photosynthesis. Bud dormancy helps protect leaves or flowers that have not yet bloomed in
late autumn. Seed dormancy is a variation that can last the longest because seeds don’t have to germinate
until the external condition is completely favourable according to their liking. Overall, plant dormancy can
stabilize the ecosystem by conserving energy and water supply. Their withdrawal from resource competition in
highly demanding seasons supports the survival of active organisms that can't be dormant. It also controls the
microclimate by providing shade and reducing soil erosion (wearing away dirt and soil).
The two most prominent ways of wildlife adaptation during autumn include migration and preparation for
hibernation. Many animal species from birds to mammals move to warmer places as temperature drops below
optimal and food becomes scarce. Migrating behaviours begin during early fall, most recognizable by the
arrow-like formations of wild geese searing through the sky. Displacement of animals is favourable from a
short-term perspective since migrating species contribute to nutrient redistribution by transporting organic
matter across different ecosystems, pollination and seed dispersal. During the time of certain species’
absence, the original breeding ground would change in response to gaps in local food webs, potentially
inducing differences in the interaction dynamics between organisms. As soon as autumn sends its cues, many
species have shown decreased exertion, accumulative hunting and preying behaviours. Hibernation (also
called torpor) is a state of inactivity and metabolic depression in animals. Similar to plant dormancy,
hibernation hopes to balance the food chain (that would otherwise be exceedingly stressed) by eliminating
some of the top predators’ insatiable appetites unaffordable in the harshness of an approaching winter. This
reduces the chances of overconsumption of limited food supplies, which directly leads to extinction and
dominance of one particular species in the ecosystem. Some less energy-mandating species like squirrels and
hedgehogs may burrow in the ground to boost soil productivity and permeability because the hollow space in
the soil aids both the plant roots and microbes living in the surroundings.
Many factors acclimate to the changing environment in autumn owing to survival requirements and ecosystem
stabilization. Plants undergo leaf senescence and dormancy to recycle nutrients and make provision for
smaller organisms. Microbes perform carbon sequestration and aeration to restore proper soil condition and
fertility, while animals resort to migration or hibernation to balance the food chain by conserving rare resources
in the forthcoming unproductive season. These unique ways of adaptation of life forms expressed are critical to
ensuring the health and biodiversity of a biome throughout yearly fluctuation and up to four seasonal changes
in some places, among which autumn is a remarkable one indeed.
References:
https://www.freedomgpt.com/wiki/annual-cycle
https://www.britannica.com/science/autumn-season
https://writescape.ca/site/2022/10/seasonal-symbolism/
https://www.arabiaweather.com/en/content/why-do-trees-fall-leaves-in-the-fall
https://academic.oup.com/femsec/article/87/2/475/482438
https://www.nature.com/articles/s43017-022-00366-w
https://www.reconnectwithnature.org/news-events/big-features/autumn-animal-behavior-prepare-for-winter/
https://besjournals.onlinelibrary.wiley.com/doi/10.1111/1365-2745.13577
https://www.thinktrees.org/wp-content/uploads/2019/07/Plant-Adaptations.pdf
https://molhort.biomedcentral.com/articles/10.1186/s43897-021-00006-9
