Keywords: pollination, ecosystem, agriculture, habitats, pollinator, diversity, urbanization
Next Generation Science Standards:
- MS-LS2-5. Evaluate competing design solutions for maintaining biodiversity and ecosystem services.
- MS-ESS3-3. Apply scientific principles to design a method for monitoring and minimizing a human impact on the environment.
- HS-LS2-7. Design, evaluate, and refine a solution for reducing the impacts of human activities on the environment and biodiversity.
For centuries, cities have been a means of opportunity for jobs, economic growth, education, health services, empowerment, and social mobilization. But as more humans move to cities, more natural land must be urbanized, or changed into buildings and homes to accommodate for the increase in populations. While urbanization has brought many opportunities for people, it has also caused negative consequences for the surrounding ecosystem, such as loss of biodiversity, specifically the loss of pollinators.
The importance of Pollination
Pollination is a plant reproductive strategy in which pollen (the sex cells of plants) is moved within or between flowers with the help of pollinators such as insects, birds, wind, or water. The success of pollen being transferred to another flower results in fertilization, which will lead to a seed that will develop into a new plant offspring. When a pollinator visits a flower, it is rewarded with a sugar-rich nectar, while the pollen from plants gets transferred to another flower in the hopes of creating offspring.
The plant-pollinator relationship is an example of coevolution, where two or more species evolve adaptations over time to benefit from one another. Plants have adapted the structure of their flowers in order to attract a specific type of pollinator. For instance, bats visit white flowers because they pollinate at night, while hummingbirds visit flowers with long, tubular corollas (collection of showy petals) adapted for their longer beaks. Some plants, including some orchid species, can even mimic a pollinator’s pheromones or appearance in order to attract more attention from those insects.
These pollinators play a vital role in terrestrial ecosystems; without them, plants would not be able to create new populations. Pollinators are also extremely important for the plants humans depend on for food, medicine, spices, fibers, and beverages. Insect-pollinated crops contribute about $20 billion dollars to the U.S. economy. Without pollinators, we would be in trouble because we would no longer have valuable crops, such as almonds, apples, strawberries, cucumbers, pumpkins, and more.
How cities hurt pollinators
Recently, scientists have observed a steep decline in pollinator populations. Bee populations have suffered most, with some states losing up to 60% of their hives from 2014 to 2015. The situation has gotten so bad that the United States listed bumblebees on the endangered list for the first time in 2017.
Bees aren’t the only pollinators at risk. The decline of pollinator diversity has also become a real problem. Each flower is specially adapted to attract a type of pollinator. If the species that a plant relies on to disperse its pollen becomes extinct, then that plant would have serious trouble reproducing.
What has caused pollinators to decline? There has been a myriad of threats to pollinator populations; climate change, overuse of pesticides, deforestation to name a few. However, urbanization has been one of the leading factors in pollinator decline.
Urbanization results in habitat loss, destroying the natural environment where pollinators live. As the human population continues to grow and become more urban, cities will need to expand, taking up more land. If the pollinators lose their habitats and their populations continue to decline, agriculture may not be able to meet the growing food demand.
So what can be done to meet the needs of people without harming pollinators? With the growing trend of urbanization, people need to be creative with solutions on how to prevent pollinator loss and instead increase pollinator diversity. Some universities, as the University of Washington, has partnered with local community members, scientists, and businesses to create an Urban Pollination Project to investigate pollination in urban settings and how to increase pollinators in cities. Some cities have built rooftop gardens that people can enjoy, such as the Highline trail in New York City.
Additionally, scientists have become involved in urban pollination citizen science projects, in which community volunteers help scientific research by helping to collect data. This involves creating more urban gardens enjoyed by the community for food sustainability, protecting parks and other urban natural lands to allow for pollinator traffic. Cities, such as Copenhagen, have required buildings to have rooftop gardens for sustainability. Initiatives like these can allow for pollinators and people to coexist.