Introduction to Ecosystem Ecology
Prof. Dr. Yingzhi Gao
Northeast Normal University
Phone:13664319768
Email:gaoyz108@nenu.edu.cn
Textbook:
• Principles of Terrestrial Ecosystem Ecology
by F. Stuart Chapin III
Pamela A. Matson
Harold A. Mooney
Course Goals
•Understand basic principles
Interaction, scale, process, pools and fluxes, trophic,
Integration，regulation and management
•Get you involved
–Participate!!!
Why should we care about
ecosystem ecology?
• Ecosystem ecology provides a
mechanistic basis for understanding the
Earth System
• Ecosystems provide goods and services
to society
• Human activities are changing
ecosystems (and therefore the Earth
System)
Complex: human activity influence
What is Ecosystem Ecology?
• Study of interactions among
organisms and their physical
environment as an integrated
system
What is an ecosystem?
• bounded ecological system
consisting of all the organisms in an
area and the physical environment
with which they interact
– Biotic and abiotic processes
– Pools and fluxes
System definition nutrient cycling
Living
aboveground
phytomass
System output:
Degistatio
n
Animals
System input:
- wet and dry
deposition
- N2-fixation
- fertilization
- water inflow
Standing dead
Litter
Excr
eta
Uptake for
shoot production
internal
nutrient cycling
(Du
ng)
Retranslocation
Excreta (Urine)
Living
belowground
phytomass
Washout
Exudation
Dead
belowground
phytomass
Decomp
osition
Humus
Mineralization
Uptake
Mineral
nutrients in
soil solution
Mineralization
Decompos
ition
- water outflow
- wind erosion
- losses to air
(denitrification)
- fire (burning dung)
- haymaking
- animal products
(meat, wool,...)
Nitrogen fluxes and pools 2004 and 2005 (g/m²)
Living shoot
shoot
Living
TO
1.4 - 2.3
T79
2.2 - 3.1
TO
Sheep uptake 1,0
TO
0.1
T79
2.2 - 3.1
Living roots
roots
Living
TO
4.5
T79
8.3
TO
0.23 - 0.26
T79
25.4
Decomposition
TO
T79
0.05
0.6
T79
2.8 - 2.9
Root N-uptake
TO
5
T79
7
Soil Humus N
(0-20 cm)
Plant
available
N
Dead roots
roots
Dead
TO
16.7
Export
TO
0.6
Standing dead
dead and
and
Standing
litter
litter
N-uptake
N-uptake
TO
1.4 - 2.3
Sheep
TO
0.4
Decomposition
TO
3-5
T79
5-9
TO
330
T79
400
Ecosystem Structure:
Trophic relations
• Trophic relationships determine an
ecosystem’s routes of energy flow and
chemical cycling
• Trophic structure refers to the feeding
relations among organisms in an ecosystem
• Trophic level refers to how organisms fit in
based on their main source of nutrition,
including
Trophic levels
• Primary producers: autotrophs (plants, algae,
many bacteria, phytoplankton),
• Primary consumers: heterotrophs that feed on
autotrophs (herbivores, zooplankton);
• Secondary consumers heterotrophs that feed on
primary consumers;
• Tertiary consumers (quatenary consumers);
• Detritivores (organisms that feed on decaying
organic matter, bacteria, fungi, and soil fauna)
• Omnivores (feed on everything), frugivore,
fungivore…….
Other Definitions
• An ecosystem is a bounded ecological
system that includes all the organisms and
abiotic pools with which they interact.
• An ecosystems is the sum of all of the
biological and nonbiological parts that
interact to cause plants grow and decay, soil
or sediments to form, and the chemistry of
water to change.
Ecosystem Ecology
• The study of the movement of energy and
materials, including water, chemicals,
nutrients, and pollutants, into, out of, and
within ecosystems.
• The study of the interactions among
organisms and their environment as an
integrated systems.
Example 1
• Small scale: e.g., soil core, appropriate for
studying microbial interactions with the soil
environment, microbial nutrient
transformations, trace gas fluxes,…
Example 2
• Stand: an area of sufficient homogeneity
with regard to vegetation, soils, topography,
microclimate, and past disturbance history
to be treated as a single unit.
Appropriate for studying whole-ecosystem
gas exchange, net primary productivity,
plant-soil-microbial nutrient and carbon
fluxes
Example 3
• Natural boundaries: sometimes, ecosystems
are bounded by naturally-delineated borders
(lawn, crop field, lake).
Appropriate questions include whole-lake
trophic dynamics and energy fluxes (e.g.
Lindeman)
Example 4
• Watershed: a stream and all the terrestrial
surface that drains into it.
Watershed studies use stream as “sample
device”, recording surface exports of water,
nutrients, carbon, pollutants, etc., from the
watershed.
Temporal Scale
• Instantaneous
Temporal Scale
• Instantaneous
• Seasonal
Temporal Scale
• Instantaneous
• Seasonal
• Succession
Temporal Scale
•
•
•
•
Instantaneous
Seasonal
Succession
Species migration
Temporal Scale
•
•
•
•
•
Instantaneous
Seasonal
Succession
Species migration
Evolutionary history
Temporal Scale
•
•
•
•
•
•
Instantaneous
Seasonal
Succession
Species migration
Evolutionary history
Geologic history
General approaches
• Systems approach
– Top-down approach
General approaches
• Systems approach
– Top-down approach
• Comparative approach
– Bottom-up approach
– Based on processes
Historical roots
• Community ecology
– Elton
– Clements
• Geography
– Warming, Schimper, Walter
• Soils
– Jenny
Systems Approach
•
•
•
•
•
Lindeman: Trophic dynamics
Odum: Energy and nutrient flows
Margalef: Information transfer
O’Neill: Hierarchy theory
Holling: Resistance and resilience
Process Approach
• Jenny: State factors
• Billings, Mooney: Ecophysiology
Tansley, British plant ecoslogist
• The use and abuse of vegetational concepts
and terms. Ecology 16: 284-307
• First to coin term, “ecosystem”
• Emphasized interactions between biotic and
abiotic factors
• Argued against exclusive focus on
organisms
Hans Jenny, Soil scientist
• Factors of soil formation, 5 state factors that
constrain soil and ecosystem development
• Soil = function of Climate, organisms, parent
material, relief (topography) and time, or
s=f(clorpt)
• Many patterns of soil and ecosystem properties
correlate with state factors (climate and vegetation
structure and function)
Ramond Lindeman
• Qualified pools and fluxes of energy in a lake
ecosystem emphasizing biotic and abiotic
components and exchange
• Fluxes of energy, critical “currency” in ecosystem
ecology, basis for comparison among ecosystems
• Synthesized with mathematical model
• Coupling of energy flow with nutrient cycling
J. D. Ovington, English forester
• Central question, how much water and nutrients
are needed to produce a given amount of wood?
• Constructed ecosystem budgets for nutrients,
water, and biomass
• Also included inputs and outputs: exports of logs
involves exports of nutrients (thus inputs of
nutrients required to maintain productivity
• One of the first to state the need for more basic
understanding of ecosystem function for managing
natural resources
H. T. Odum and E. P. Odum
• Used radioactive tracers to study movement
of energy and materials through a coral reef,
documenting patterns of whole system
metabolism
• System analysis- ecosystem as a lifesupport system concept
Earth System and Global Change
• Making history in ecosystem ecology
• Impact of human activities on Earth has led to the
need to understand how ecosystem processes
affect the atmosphere and oceans
• Large spatial scale, requiring new tools in
ecosystem ecology (fluxes tower measurements of
gas exchange over large regions, remote sensing
from satellites,global networks of atmospheric
sampling, global models of ecosystem
metabolism).
Frontiers in ecosystem ecology
• Integrating systems analysis, process
understanding, and global analysis
• How do changes in the environment alter the
controls over ecosystem processes? What are the
integrated consequences of these changes? How
do these changes in ecosystem properties
influence the Earth system?
• Rapid human-induced changes occurring in
ecosystems have blurred any previous distinction
between basic research and management
application
www.magim.net