Conservation and Restoration

Essential Question

How can people reduce harm to ecosystems and restore them?

People can reduce harm to ecosystems and help damaged ones recover. In this lesson, you’ll learn the main strategies for protecting biodiversity, how wildlife crossings in Banff National Park reduced collisions, how restoration is tested with data, and how to evaluate a solution.

Protecting Biodiversity

• Conservation: protecting and managing species and habitats
• Each strategy answers a threat
• Strategies work best together
• Choices involve trade-offs

Conservation means protecting and managing species and their habitats. Each common strategy responds to a threat from the last lesson. Parks and reserves protect habitat. Corridors and crossings reconnect fragments. Restoration repairs damaged ecosystems. Controlling invasive species, setting catch limits, and reducing pollution and greenhouse gas emissions address other threats. These strategies often work best together, and each one has costs and trade-offs that people have to weigh.

Connecting Habitats

• Roads split habitat and cause collisions
• Crossings let animals pass over or under roads
• Fencing guides animals to crossings
• Fencing alone can isolate populations

Roads can split habitat and cause collisions between vehicles and animals. In Banff National Park in Canada, fencing with underpasses and overpasses along the Trans-Canada Highway reduced wildlife-vehicle collisions by more than 80 percent overall and by more than 96 percent for elk and deer, according to Parks Canada. Fencing guides animals to the crossings. Scientists note that fencing alone would block movement and isolate populations, so the crossing structures matter. The results differ by species, and the reduction for large carnivores has been less clear.

Restoring Ecosystems

• Restoration helps damaged ecosystems recover
• Remove the cause of harm first
• Replant or reintroduce native species
• Compare with unrestored sites

Restoration helps a damaged ecosystem recover. It often starts by removing the cause of harm, such as pollution or an invasive species, and then replanting or reintroducing native species. Scientists test whether restoration works by comparing restored plots with unrestored plots, and by measuring results over time. The sample data show native plant cover rising in restored plots while staying low in unrestored plots. Recovery can take many years, and a restored ecosystem may not become identical to the original one.

Evaluating Solutions

• Define the problem and the goal
• Compare effectiveness, cost, and side effects
• Test with data, then refine
• Include the needs of people

A good solution is judged against criteria such as how well it works, what it costs, what side effects it has, and how it affects people. Engineers and scientists design a solution, test it by collecting data, and then evaluate and refine it. A wildlife crossing, for example, can be tested by counting collisions before and after it is built and by counting animals that use it. A solution that works well but is too costly, or that harms people’s livelihoods, may need to be changed. Models and simulations can help test ideas before they are built.

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Worked Examples

Try each problem on your own first, then open the solution to check your work.

Example 1: Match the Solution

Use the conservation strategies. Choose a strategy that responds to each problem: (a) fertilizer runoff is causing algal blooms in a lake, (b) a highway splits the habitat of a deer population, (c) an invasive plant is crowding out native plants, (d) a fish stock is declining because of overharvesting.

Show the solution

1. (a) Algal blooms: the cause is nutrient pollution, so reduce runoff, for example with less fertilizer or planted buffer strips along waterways.
2. (b) Highway splitting habitat: build crossings with fencing to connect the habitat.
3. (c) Invasive plant: control or remove the invasive species and replant native plants.
4. (d) Declining fish stock: limit the harvest with catch limits or closed seasons.
5. Answer: (a) reduce pollution, (b) connect habitat, (c) control invasive species, (d) limit harvest.

Example 2: Did the Restoration Work?

Use the graph. Did restoration increase native plant cover? Write a claim, evidence, and reasoning.

Show the solution

1. Read the graph: restored plots rose from 5% to 61% over 8 years. Unrestored plots were 6% at year 8.
2. Claim: in these sample data, restoration increased native plant cover.
3. Evidence: at year 8, restored plots had 61% cover and unrestored plots had 6%, a difference of 55 percentage points.
4. Reasoning: the plots started with the same cover, so the unrestored plots act as a comparison. The large difference suggests that the restoration, and not time alone, caused the increase.
5. Answer: Yes. At year 8, restored plots had 61% cover and unrestored plots had 6%, a difference of 55 percentage points.

Example 3: Collisions After Fencing

Before fencing and crossings, a section of highway averaged 100 elk-vehicle collisions per year. Elk collisions then fell by more than 96%. Estimate the number of elk-vehicle collisions per year after the fencing.

Show the solution

1. Fraction remaining: 100% − 96% = 4%, or 0.04.
2. Collisions after: 100 × 0.04 = 4 collisions per year.
3. Answer: About 4 collisions per year. Because the reduction is reported as more than 96%, the actual number would be at most about 4.

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Practice

Match conservation strategies to threats, use experiment data as evidence, calculate the effect of a reduction, and evaluate a solution. Try it on your own first, then check your work with the answer key.

• Conservation and Restoration Practice Worksheet (PDF)
• Conservation and Restoration Practice Answer Key (PDF)

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Lesson Slides

• 3.9 Conservation and Restoration Slides (PDF)

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Big Ideas

• Conservation protects and manages species and habitats
• Different strategies answer different threats and work best together
• Fencing with crossing structures reduced collisions in Banff by more than 80 percent overall
• Restoration is tested by comparing restored and unrestored sites over time
• A solution is judged by how well it works, its cost, side effects, and effects on people

Back to the essential question: people can reduce harm by protecting and connecting habitat, restoring damaged ecosystems, controlling invasive species, limiting harvests, and reducing pollution. Scientists and engineers test these solutions with data and refine them. This is the end of Unit 3, so you can return to the list of Biology units.

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