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Quiz: Minnesota's Ecoregions and Growing Conditions

Test your understanding of Minnesota's ecoregions, hardiness zones, soils, and growing conditions with these review questions.

1. How many major ecoregions does Minnesota contain?

  1. Two: prairie and forest
  2. Four: tallgrass prairie, deciduous forest, coniferous forest, and prairie-forest border
  3. Six: prairie, savanna, deciduous forest, boreal forest, wetland, and tundra
  4. Three: tallgrass prairie, deciduous forest, and coniferous forest
Show Answer

The correct answer is B. Minnesota contains four major ecoregions: tallgrass prairie in the west and southwest, deciduous forest in the central and southeastern regions, coniferous (boreal) forest in the northeast, and the prairie-forest border, which is the transition zone where prairie and forest intermingle. The prairie-forest border is often overlooked but is ecologically significant, especially for Twin Cities residents.

Concept Tested: Minnesota Ecoregions

See: Chapter 2

2. What is the primary environmental factor that historically determined where the prairie-forest border fell in Minnesota?

  1. Soil pH levels
  2. Elevation above sea level
  3. Fire frequency
  4. Proximity to lakes
Show Answer

The correct answer is C. Fire was the primary force determining the boundary between prairie and forest. Frequent fires favored grasses and pushed the border eastward by killing tree seedlings. When fire was suppressed, trees advanced westward into former prairie. This dynamic boundary is also called the tension zone or ecotone, and it contains unique plant communities like oak savannas.

Concept Tested: Prairie-Forest Border

See: Chapter 2

3. Approximately what percentage of Minnesota's original tallgrass prairie remains today?

  1. About 25%
  2. Less than 2%
  3. About 10%
  4. About 50%
Show Answer

The correct answer is B. Less than 2% of Minnesota's original 18 million acres of tallgrass prairie remains today, making it one of the most endangered ecosystems in North America. The vast majority was converted to agriculture because the deep, rich prairie soils — built over thousands of years by prairie grass root systems — are among the most fertile in the world.

Concept Tested: Tallgrass Prairie Region

See: Chapter 2

4. What does "deciduous" mean in the context of deciduous forests?

  1. Cone-bearing
  2. Evergreen and needle-leaved
  3. Falling off, referring to trees that drop their leaves each autumn
  4. Ancient or old-growth
Show Answer

The correct answer is C. Deciduous means "falling off" and refers to hardwood trees that shed their leaves each autumn. Minnesota's deciduous forest region covers the central and southeastern parts of the state and includes species like Sugar Maple, Red Oak, and American Basswood. The annual leaf drop creates brilliant fall colors and enriches the forest floor with organic matter.

Concept Tested: Deciduous Forest Region

See: Chapter 2

5. Which USDA Hardiness Zone covers the Twin Cities metro area?

  1. Zone 3a
  2. Zone 3b
  3. Zone 5a
  4. Zone 4b
Show Answer

The correct answer is D. The Twin Cities metro area falls within USDA Hardiness Zone 4b, which has average minimum winter temperatures of -25 to -20 degrees Fahrenheit. Zone 4b is the most commonly referenced zone for Twin Cities gardeners. Most Minnesota native plants are hardy to at least Zone 4b, giving metro-area gardeners a wide selection of native species.

Concept Tested: Zones 3a Through 5a

See: Chapter 2

6. A gardener in Duluth (Zone 3b) purchases a prairie plant grown from seed collected in southern Kansas. What is the most likely problem?

  1. The plant will be too tall for northern gardens
  2. The plant may not complete its life cycle within the shorter northern growing season
  3. The plant will attract the wrong pollinators
  4. Kansas soil bacteria will harm Minnesota soil
Show Answer

The correct answer is B. Native plants evolve to complete their life cycles within their local growing season. A prairie plant from Kansas is adapted to a much longer growing season (possibly 180+ days) compared to Duluth's approximately 110-130 frost-free days. The plant may not have time to fully flower and set seed before the first frost. This is why sourcing plants from local ecotypes — populations adapted to your specific region — is so important.

Concept Tested: Growing Season Length

See: Chapter 2

7. Which type of wetland is characterized by acidic conditions, sphagnum moss, and nutrient-poor water from rainfall?

  1. Marsh
  2. Fen
  3. Bog
  4. Floodplain forest
Show Answer

The correct answer is C. Bogs are acidic wetlands with a thick mat of sphagnum moss that receive water mainly from rain rather than groundwater. This makes them nutrient-poor, which is why they support specialized plants like pitcher plants and Labrador tea. Fens, by contrast, are groundwater-fed and less acidic. Marshes are shallow-water wetlands with emergent plants, and floodplain forests are wooded areas along rivers.

Concept Tested: Minnesota Wetland Types

See: Chapter 2

8. What does a USDA Hardiness Zone number primarily tell you about a location?

  1. The average summer high temperature
  2. The total annual rainfall
  3. The average annual extreme minimum winter temperature
  4. The number of frost-free days in the growing season
Show Answer

The correct answer is C. USDA Hardiness Zones are based on the average annual extreme minimum temperature at a location. Each zone represents a 10-degree Fahrenheit range. The zone number tells you whether a perennial plant can survive winter cold in your area. However, hardiness zones do not account for other important factors like soil type, light availability, moisture, or summer heat.

Concept Tested: USDA Hardiness Zones

See: Chapter 2

9. Which soil type in Minnesota was formed by thousands of years of prairie grass growth and is among the most fertile in the world?

  1. Spodosols (boreal soils)
  2. Entisols (sandy soils)
  3. Mollisols (prairie soils)
  4. Histosols (peatland soils)
Show Answer

The correct answer is C. Mollisols, or prairie soils, are deep, dark, nutrient-rich soils formed under thousands of years of prairie grass growth. Found across western and southern Minnesota, they are typically loamy with high organic matter content. The massive root systems of prairie grasses — reaching 10 to 15 feet deep — built these remarkably fertile soils over millennia. They are now the foundation of Midwest agriculture.

Concept Tested: Minnesota Soil Types

See: Chapter 2

10. You discover your garden has heavy clay soil that holds water and drains slowly. Which of the following native plants would be the best match for these conditions?

  1. Prairie Dropseed, which prefers dry sandy soils
  2. Wild Blueberry, which needs acidic sandy soils
  3. Pasque Flower, which thrives in well-drained dry prairies
  4. Blue Flag Iris, which tolerates moist to wet conditions
Show Answer

The correct answer is D. Blue Flag Iris is a moisture-tolerant native plant well suited to heavy clay soils that hold water. Prairie Dropseed and Pasque Flower are adapted to dry, sandy, well-drained conditions and would struggle in clay. Wild Blueberry requires acidic sandy soils typical of the boreal northeast. Matching plants to your actual soil conditions is just as important as matching them to your hardiness zone.

Concept Tested: Minnesota Soil Types

See: Chapter 2

Ready to use these ideas rather than recall them? Try the Applied Quiz for this chapter — ten scenario questions that put you in a situation and ask what to do.