Global climate and the distribution of plant biomes

Grasslands

simulated C3 and C4 grass distribution (%)

C3

C4

Figs. 10/11. Simulated distribution of C3 grasses for 1990 to 2000. (Woodward et al. 2004)

Figure 12. Scatter diagrams of grass cover (percentage) against mean minimum annual temperature (oC) and annual total precipitation (mm). (a) C3 grasses; and (b) C4 grasses. The color scheme is as for figures 10 and 11. Boundary lines are drawn by eye.

Mean minimum annual temperature (oC);

An

nu

al t

otal

pre

cip

itat

ion

(m

m y

r-1)

0 10 20 30 40 50 60 70 80 90 100

C4 grassland

C3 grassland

Global climate and the distribution of plant biomes

ForestsGlobal warming → Ecosystem (biome) change →

Life-form change → New biome (e.g., cropland)

Fig, 9. Scatter diagrams of tree cover (percentage of ground cover) against mean minimum annual temperature (oC) and annual total precipitation (mm). (a) Evergreen; and (b) deciduous. Precipitation totals are capped at 3000 mm to provide greater resolution for climates with low precipitation. The color scheme is as for figure 2 to 5. Boundary lines are drawn by eye. (Woodward et al. 2004)

Minimum yearly temperature (oC);

An

nual

tot

al p

reci

pita

tion

(m

m y

r-1)

Global climate and the distribution of plant biomes

Croplands

0 10 20 30 40 50 60 70 80 90 100

Fig. 13. The global distribution of cultivated and managed land. (Modified from GLC 2000)

Fig.14. Scatter diagram of cultivated and managed land cover (percentage) against mean minimum annual temperature (oC) and annual total precipitation (mm). The color scheme is as for figure 13. (Woodward et al. 2004)

Global warming→ Ecosystem (biome) change→ Life-form change→ New super-biome (e.g., cropland)

Mean minimum annual temperature (oC);

An

nu

al t

otal

pre

cip

itat

ion

(m

m y

r-1)

Fig. 10 Examples of potential abiotic and biotic controls on ANPP of terrestrial ecosystems. Relationships between ANPP and a annual precipitation (redrawn from Gower 2002) and b average height of the vegetation (data taken from Saugier et al. 2001) for different biomes. Note that classification of biomes and ANPP values for a given biome might differ between the two studies in a BODBL boreal deciduous broadleaved, BODNL boreal deciduous needle-leaved, BOENL boreal evergreen needle-leaved, DESRT deserts, TEMGS temperate grasslands, TROGS tropical grasslands, TEDBL temperate deciduous broadleaved, TEEBL temperate evergreen broadleaved, TEENL temperate evergreen needle-leaved, TRDBL tropical deciduous broadleaved, TREBL tropical evergreen broadleaved, TUNDR tundra, WDLND woodlands; in b BORFT boreal forests, CROPS crops, DESRT deserts, MEDSH Mediterranean shrublands, TEMFT temperate forests, TEMGS temperate grasslands, TROFT tropical forests, TROGS tropical savannas and grasslands, TUNDR tundra. Correlation coefficient in a r=0.90 (P<0.001, n=13) and in b r=0.91 (P<0.001, n=8)

(Garnier & Navas 2012)

Biome and NPP

Annual precipitation (mm/yr)

Vegetation height (m)

Ab

ove

gro

un

d n

et p

rim

ary

pro

du

ctiv

ity

(kg

/m2/y

r)

CO2

Other environmental factorse.g,windprecipitationsoil moisturelitter decomposition

EcosystemTemperature

Photosynthesis

12H2O + 6CO2 + solar energy

C6H12O6 + 6O2 + 6H2O

chlorophyll enzymes

(from leaf)

[carbonhydrate] (to air)

[2966 kJ]

CO2, 6 moles = 134.4 liters at standard temperature and pressure

for making budget

(from root)

temperature

Fig. 1. The status of water in the soil as measured by the diameter of soil pores that remain water-filled.

1000 100 10 1 0.1 0.01 0.001Pore size (mm)

FIE

LD

CA

PAC

ITY

PE

RM

AN

EN

T

WIL

LIN

G P

OIN

T

Roo

tlet

dia

met

ers

Roo

t h

airs

Water drains away freely

Water unavailable to plantsAvailable water

Tree: secondary growth (auxetic growth)

Herb:Dicotyledons: main root (taproot) + fine root (rootlet)

Fine root < f 3-5 mmMonocotyledons: adventitious root

Three types of root systems

de Kroon & Visser (2003)

Rhizosphere: areas that are influenced by roots

The roles of roots1. Nutrient and water transportation2. Supporting system

Fig. 2. The root system of a wheat plant grown in a sandy soil containing a layer of clay.

根系

Dicot Monocot

Figure 3.8. a. Radiant energy from the sun is categorized according to the wavelengths of the electromagnetic spectrum. b. Visible light contains various colors of light, some of which are absorbed by chlorophyll. c. Leaves appear green to the human eye because the color green is largely reflected or transmitted by chlorophyll.

transmitted

reflected

c.

absorbed

Dec

reas

ing

wav

elen

gth

b.a.

Hig

h e

ner

gyL

ow e

ner

gyultraviolet

X rays

visible light

radio waves

infrared

microwaves

gamma rays

prism

transmitted and reflected

absorbed

absorbed

760 nm

380 nm

Red

Orange

Yellow

Green

Blue

Violet

EfficiencyExample:The percentage of the solar energy reaching the plant that is used in photosynthesis or else ‘fixed’ as organic materials

Solar energy x% of energy absorbed for photosynthesisx% = Efficiency

Plant productivity and use of solar energy(Burton 1998)

Plant productivity (in a year)(1500-6000 kg carbon/ha/yr) × (8000 kcal/kg carbon)

= 12 × 106 to 48 × 106 kcal/ha/yr

Solar radiation arriving ground level= 11.6 ×109 kcal/ha/yr

(Higher) Efficiency(48 × 106)/(11.6 ×109) × 100 = 0.4%

Quiz: What is the lower efficiency?

Fig. 1. Widening and narrowing of the temperature range of germination of a summer annual in relation to the temperature in the habitat during the seasons. The broken line indicates the mean daily temperature in the field. Solid lines indicate maximum (Tmax) and minimum (Tmin) temperature for germination. In the hatched area the actual and required temperature overlap. (Adapted from Karssen 1982). (Vleeshouwers et al. 1995)

Fig. 2. Diagrammatic representation of the interaction of seed and environment in the process of germination. The degree of dormancy defines the germination requirements of the seed. If these requirements are met by the environment the seed will germinate. It should be realized that the degree of dormancy of a seed at a certain moment is influenced by the environmental conditions it has experienced during its existence, back to the conditions in which it has ripened at the mother plant.

Degree of dormancy(seed characteristic)(continuous scale)

+Environment

Germination(the seed’s response)

(yes or no)

Tem

pe

ratu

re, o

C

Oct Jan Apr Jul

40

30

20

10

0

Fig. 3. Simulation of seasonal changes in the range of temperatures over which at least 50% of exhumed Polygonum persicaria seeds germinate. Solid lines represent maximum and minimum temperature required for 50% germination in water, calculated according to a descriptive model based on temperature derived parameters. The dotted line indicates air temperature at 1.50 m. Hatched areas indicate overlap of field temperature when germination in Petri dishes outdoors actually increased above () or decreased below () 50%. (Adapted from Bouwmeester & Karssen 1992)

Tem

per

atu

re (

oC

)

1986 1987 1988 1989

30

20

10

0

-10

D J F M A M J J A S O N D J F M A M J J A S O N D J F M A M J J A

Survival and changes in germination response of Rumex obtusifolius, Polygonum longisetum and Oenothera biennis during burial at three soil depths

Fig. 1: Seed germination curves for three species buried at three soil depths (3, 10 and 30 cm). Mean germination percentage on six replicates was shown. All standard errors are less than 4 and are not shown in the figure, Closed symbols indicate temperature changes from low to high (L-H) and open symbols from high to low (H-L). Circles, squares and triangles are for seeds buried at depths of 3, 10 and 30 cm, respectively.

(Tsuyuzaki 2006)

Rumex obtusifolius Polygonum longisetum Oenothera biennis

Ger

min

atio

n p

erce

ntag

e

Temperature fluctuation (oC)

1525

2515

535

355

1525

2515

535

355

1525

2515

535

355

Spring

Spring Spring

AutumnAutumnAutumn