Pollinators: Threats and Challenges
Background
Many of Canada’s pollinators are challenged by human activity that is removing and polluting natural spaces that are habitat – or home - for these animals. In particular, habitat is frequently lost with development for commercial buildings, large scale agriculture and parking lots as well as residential spaces. While some trees and flowers can and are later planted on these properties, they are typically both minimal and often not anywhere near as beneficial as the plants that were removed. As a result of these factors, natural habitats have been degraded (weakened, less useful to pollinators), lost, or fragmented (breaking apart large areas of natural habitat that would otherwise be there).
More specifically, pollinators experience a lack of food from expanses of lawn which are baren compared to the rich diversity of native plants that would have existed there before. When flowers are planted, some are sterile as pollen and nectar producing abilities are reduced or eliminated in favour of showier flower heads with additional petals. Other challenges in our unnatural environments are time gaps between blooms rather than having plants that take turns blooming from early spring through to late fall. Likewise, monoculture planting where you only have a mass of one or two kinds of plants only serves a limited number of pollinators. We can see this in our gardens but also in the main agricultural industry unlike small farms and the older style of farming of having various crops as well as hedgerows in between with flowering trees and shrubs. Another way we reduce their food in our current living model is that often when we do think of supporting an animal, we don’t always consider their different stages – and therefore needs – of life. For instance, larval food plants are crucial for our butterfly and moth species that need leaves of certain plants for the caterpillar stage of development. In addition to including such plants, having tolerance for some munching is also key.
In addition to affecting the food supply, removing this habitat often creates a lack of shelter for avoiding predators and harsh weather, for nesting sites, places to spy their next meal and for over wintering. This is often in the form of trees and shrubs, including dead or dying trees (snags) which are critical for our cavity nesting birds such as woodpeckers but can also be helpful to some pollinator species. Other forms of shelter pollinators need include fallen logs, leaf litter, old hollow plant stems and dense plantings of herbaceous vegetation. While we can have attractive formal gardens, we need to find ways to include elements that in the past might have been considered untidy but can instead be subtly and naturally woven into our spaces.
Invasive plants are another challenge that can affect pollinators. These are plants that have come from another place and are able to spread quickly. In doing so they outcompete with our native plants, ones in which our local wildlife have coevolved. This pushes out native plants and with it, a food source for many animals. Some of these plants have arrived by accident but others, like the Norway Maple, are planted on purpose.
Another threat to pollinators is the use of pesticides and herbicides, by both ourselves and the horticultural industry. These kill or seriously harm insects directly and in doing so, affects the food source of those that eat them like songbirds but also other pollinators like hummingbirds which need protein from spiders and insects. When buying plants ensure they haven’t been treated with neonicotinoids, an especially dangerous group of pesticides that can stay with the plant from when it is a seed to its own seed produced. In your own garden, avoid any products that kill insects, using instead gentler means of repelling or dealing with insect challenges.
Climate change, in particular global warming, has disrupted the migration patterns and blooming seasons of plants. Flowering plants are moving to cooler temperatures and leaving pollinators behind as they are not adapting to the cooler temperature at the same pace as flowering plants. Flowers are also blooming earlier than their seasons due to warmer temperatures and consequentially pollinating windows are altered.
Task
Students go outside for a habitat loss game. As you recall, the four basic habitat needs for pollinators and other wildlife species are food, water, shelter and a safe space.
1. Divide students into two groups
a. Group A are pollinators with a few students in the group
b. Group B are threats and challenges with more students
Discussion questions
- Reflecting on this activity, how did you feel acting as a threat or a pollinator?
- How can we protect pollinators and ensure they have sustainable and beneficial habitats?
- 2 Each student wears a visible badge
In Advance
- Find a site for the habitat loss game
- Prepare sticky notes for the badges
- Look for sample images or items that represents specific needs of pollinators for the habitat loss game
Extensions
- Students go to their garden and identify threats and challenges to pollinators and how they could address them
- Exploratory walk — students and teachers walk two blocks from their schoolyard to examine the impact of human actions on habitat and discuss how we could protect the environment
Learning Objectives
- Understand the different habitat needs of pollinators
- Understand why natural habitats are in decline and potential effects on pollinators and other wildlife
Method
- Through roleplay, students learn about degradation and decline of habitats and its effect on pollinators
Continue to Module 4C: Threats and Challenges Vocabulary »
