Production

1
Production

• Ch. 19

2
Objectives

• Primary production factors that affect primary
  production
• How primary production varies
• How primary production affects secondary
  production
• Secondary production

3
Primary Production

• Net primary Gross primary Respiration
• productivity productivity by
  autotrophs
• (NPP) (GPP)
  (R)
• Usually expressed as
• kcal/m2/yr
• g/m2/yr

4
In blue books

• What controls primary production in terrestrial
  ecosystems?
• Increases w/ increasing mean annual temp
  rainfall
• Temp related to increase in annual intercepted
  solar radiation
• The higher the rainfall, the more water available
  for transpiration

5
Map of Primary Productivity
6
Energy allocation plant life form influence
primary production

• What happens to primary productivity as a plant
  increases its carbon allocation to its roots?
• Why would a plant allocate more carbon to roots
  than to shoots?
• Moisture response

7
Standing Biomass
8
Primary production varies w/ time

• Ceases when plants become dormant
• Wet tropics experience little seasonal variation
  in primary productivity
• Year-to-year variations can occur due to climatic
  variations
• Disturbance can lead to yearly variation
• Also varies w/ stand age
• Ratio of leaveswoody tissue changes over time
  for long-lived trees shrubs

9
Primary production limits secondary production

• E consumed undigested mass E required for
  metabolism E available for maintenance
• E left over from maintenance respiration
  incorporated into production
• Production of new tissues young
• secondary production