LANDSCAPE ECOLOGY
SREM 3011
LECTURE 11
Dr Brendan Mackey
Department of Geography
The Australian National University
2,Context
- Low frequency behaviour allows upper level to be
the context of lower level
- context is either spatially larger or more constant
over time than lower level
,the fact that summer follows spring sets the context
for plant growth
,that which is constant
NB unpredictability can be,constant” and
therefore context
B Cells aggregated to form a tissue are an example of a lower level being
contained by a higher level,C Food chain hierarchies represent non-nested
systems where the higher levels do not contain the lower levels.
cells are contained (nested)
food chains are non-nested
3,Containment
- The constituent parts are contained within each other
- Higher levels contain (bound) lower levels
- The organism contains the higher frequency
components
,cells? turn over? faster than the organism
- Nested contained systems tend to be scale-dependent
,organisms,populations,species
- Definition of non-nested hierarchies more observer-
dependent
,communities
,ecosystems
EARTH
4,Constraint
- For non-nested hierarchies,frequency and constraint
are most important characteristics
-?Constraint? can be a?passive condition?
,tree canopy provides shade and therefore
constrains seedling regeneration
- Constraint allows ecological systems to be predictable
,the level in question is constrained by an envelope
of permissible behaviours
-,Name of the game” in landscape ecology (or science
generally) is to find constraints that enable (spatial)
prediction
5,Emergent properties
- Characteristics occur which are not apparent from
examining their constituent parts
,plant behaviour not predictable from looking at
individual cells
,population viability requires understanding of
matrix (patches + corridors) not just individual
organisms
,ecosystem function cannot be predicted from
examining one species/population
,forest canopy structure is an interaction of all
the plants in a stand/patch
6,Concept of a Holon
- Each entity in a level of a hierarchy is a component
of a higher level and simultaneously sets the context
/constrains lower level
,an organism contains cells and is a member of a
population
,a population contains organisms and is part of a
community
Therefore,ecological systems require multi-scaled
analysis to be fully described.
No single level of investigation will account for ecology
of a landscape.
,populations,species,communities,ecosystems all
constitute valid,units” of spatial analysis of landscape
ecology
COMPLEX ADAPTIVE SYSTEMS
location specific,local interactions between
competitive agents are an important source
of higher level system response
external environmental conditions can either
contain or constrain agent behaviour
+ve and -ve feedbacks can influence ‘external’
environment at all scales from nano to global
ecological systems are adaptive to the extent that
the biological agents are adaptive
POPULATIONS EXIST WITHIN ECOLOGICAL
SYSTEMS:
external
drivers
local
interacting
agents
effective
environment
emergent
pattern
internally
generated
feedbacks
IMPLICATIONS FOR FORESTS
What we map as patterns of forest structure
floristics are emergent properties
- they involve a degree of stochasticity
- those particular combinations may not occur
again
The effective environment for a plant is a function
of both internally (biotic) and externally (physical)
generated processes
what are limits on biotic control of physical
processes
- locally?
- globally?
SREM 3011
LECTURE 11
Dr Brendan Mackey
Department of Geography
The Australian National University
2,Context
- Low frequency behaviour allows upper level to be
the context of lower level
- context is either spatially larger or more constant
over time than lower level
,the fact that summer follows spring sets the context
for plant growth
,that which is constant
NB unpredictability can be,constant” and
therefore context
B Cells aggregated to form a tissue are an example of a lower level being
contained by a higher level,C Food chain hierarchies represent non-nested
systems where the higher levels do not contain the lower levels.
cells are contained (nested)
food chains are non-nested
3,Containment
- The constituent parts are contained within each other
- Higher levels contain (bound) lower levels
- The organism contains the higher frequency
components
,cells? turn over? faster than the organism
- Nested contained systems tend to be scale-dependent
,organisms,populations,species
- Definition of non-nested hierarchies more observer-
dependent
,communities
,ecosystems
EARTH
4,Constraint
- For non-nested hierarchies,frequency and constraint
are most important characteristics
-?Constraint? can be a?passive condition?
,tree canopy provides shade and therefore
constrains seedling regeneration
- Constraint allows ecological systems to be predictable
,the level in question is constrained by an envelope
of permissible behaviours
-,Name of the game” in landscape ecology (or science
generally) is to find constraints that enable (spatial)
prediction
5,Emergent properties
- Characteristics occur which are not apparent from
examining their constituent parts
,plant behaviour not predictable from looking at
individual cells
,population viability requires understanding of
matrix (patches + corridors) not just individual
organisms
,ecosystem function cannot be predicted from
examining one species/population
,forest canopy structure is an interaction of all
the plants in a stand/patch
6,Concept of a Holon
- Each entity in a level of a hierarchy is a component
of a higher level and simultaneously sets the context
/constrains lower level
,an organism contains cells and is a member of a
population
,a population contains organisms and is part of a
community
Therefore,ecological systems require multi-scaled
analysis to be fully described.
No single level of investigation will account for ecology
of a landscape.
,populations,species,communities,ecosystems all
constitute valid,units” of spatial analysis of landscape
ecology
COMPLEX ADAPTIVE SYSTEMS
location specific,local interactions between
competitive agents are an important source
of higher level system response
external environmental conditions can either
contain or constrain agent behaviour
+ve and -ve feedbacks can influence ‘external’
environment at all scales from nano to global
ecological systems are adaptive to the extent that
the biological agents are adaptive
POPULATIONS EXIST WITHIN ECOLOGICAL
SYSTEMS:
external
drivers
local
interacting
agents
effective
environment
emergent
pattern
internally
generated
feedbacks
IMPLICATIONS FOR FORESTS
What we map as patterns of forest structure
floristics are emergent properties
- they involve a degree of stochasticity
- those particular combinations may not occur
again
The effective environment for a plant is a function
of both internally (biotic) and externally (physical)
generated processes
what are limits on biotic control of physical
processes
- locally?
- globally?
