Lecture 15

Question 1

Grasslands

Answer 1

land covered with herbaceous plants with <10% tree & shrub cover (UNESCO)

Question 2

Two Grass Growth Forms

Answer 2

Sod grasses

Bunchgrasses

Question 3

Sod grasses:

Answer 3

develop a solid mat above the soil

Question 4

Bunchgrasses:

Answer 4

grow in clumps. Other non-grass plants (e.g., forbs) may grow between these clumps

Question 5

Some sod grasses will take on a _____ form under different environmental conditions (e.g. dry soils)

Answer 5

Some sod grasses will take on a bunchgrass form under different environmental conditions (e.g. dry soils)

Question 6

Mixed-Grass Prairie

Answer 6

•Highly variable precipitation results in year to year variation in the type of grass cover:

• Wet years, taller grasses dominate
• Dry years, short grasses

Question 7

Distribution of Tall-Grass Prairie in Canada

Answer 7

In Manitoba and mostly in the United States

Most productive of the three North American Grasslands

Question 8

Warmer temperatures ______ decomposition, and reduce soil _____ stocks

Answer 8

Warmer temperatures increase decomposition, and reduce soil carbon stocks

Question 9

Biomass

Answer 9

•Biomass represents a small proportion of all carbon stored in soils (organic and inorganic pools)

• Above ground biomass range ~ 50 to 800 g m-2
• Mean below ground biomass ~45 to 4700 g m-2

•In most instances, below ground biomass is 2 to 3 times greater than above ground biomass

Question 10

Root-to-shoot ratios for most temperate grasslands is

Answer 10

Root-to-shoot ratios for most temperate grasslands is 4 to 5

Question 11

Tall-grass & mixed-grass ratios may reach

Answer 11

6 to 7

Question 12

Root to shoot ratios were ____ correlated with mean annual temperature, and ______ correlated with mean annual precipitation

Answer 12

Root to shoot ratios were positively correlated with mean annual temperature, and negatively correlated with mean annual precipitation