• Ecosystem- A specific biological
community defined by the the composition
of the community and the interacting
• Landscape Ecology- The study of
heterogeneous land area comprised of
interacting patches of ecosystems.
Landscape Ecology terms
• Patch- a geographic area that is relatively
homogenous with respect to its surroundings
• Ecotype- A specific ecosystem/habitat patch.
• Matrix- most extensive ecotype present with in
– Patches are often said to be embedded within the
• Scale- the unit of measure
of perception (spatial or
• The scale one observes a
landscape at greatly
influences the perception
of the landscape.
• Different organisms
perceive the ecosystem at
Landscape ecologists study landscape structure and
how that relates to functional processes.
• Structure focuses on aspects of the patches: their
density, size, shape, orientation to each other,
contrast between each other, etc. (overhead Fig 2)
• Landscape ecologist attempt to understand how
neighboring ecosystems influence each other.
Also address the impact of human landscapes on
The Edge Effect:
• Ecotones- boundaries between different
• Edge habitats often differ from both
adjacent communities due to mixed species
composition, temp., light, humidity, etc.
• Patch shape influences the amount of edge
(Fig 4.21 text)
EDGES CAN HAVE DISTINCT
Increases air flow
EDGES ARE DYNAMIC
Trees at the edge extend
their canopies and develop
Shade intolerant plants
become established in
the new high light zone
This is an edge succession
The Edge Effect:
• Edges show greater diversity than the
communities that bound them.
• The degree of diversity is greatest when:
– the adjoining communities are highly
contrasting (forest - grassland),
– the edge is long and wide,
– patches are large enough to sustain the
members of the original community.
•Habitat fragmentation our
environment is increasingly
becoming edge habitat. Our
most threatened organisms are
those that require core habitat.
Habitat Fragmentation –
Cadiz Township, WI
• Edges can often be more diverse, but at the
same time can act as “traps” with greater
risks of predation, parasitism, and or
• A large amount of preserved habitat doesn’t
mean much if most of it is edge habitat. We
must preserve large area with core habitat.
• Metapopulations- set of spatially isolated
subpopulations of a particular species living in
• Because of patch heterogeneity- some
subpopulations are more productive than others.
– some produce a surplus of individuals- sources
– some produce insufficient offspring to sustain the
– Patch conditions vary between different species.
source-sink dynamics- source populations supply individuals
to sink population through emigration and immigration via
* Harrison Ford and Conservation International
Total species diversity of a isolated ecosystem
(island) can be predicted based on: area, distance
to nearest colonizing source, and extinction rate.
1. A larger area of land can sustain more species
(More niche space)
2. Larger areas have lower local extinction rates
Diversity increases with land area:
3. Areas closer to source populations have a
higher rate of colonization.
4. Areas with greater species diversity
correspondingly have greater local
extinction rates. Why?
5. Colonization rates decline as diversity
Equilibrium amount of species diversity is determined by the
balance of these relationships (Fig 13.21 text):
1. Replace a species- Endangered Species
2. Restore structure- species composition
(but not function)
3. Restore function- water filtration, flood
control, food web.
4. Restore all the above: synthesis
• Focus is usually specific- Population recovery or
restoring habitat of endangered species. But
increasingly efforts to restore large-scale
ecosystems are underway- e.g. Florida Everglades.
• Complications: natural disturbance regimes (fire,
floods, etc), alien species, pollution, resources
(space), erosion, cost, public support, long-term
maintenance and monitoring.
Population Viability Analysis (PVA)-
modeling technique that incorporates life history,
habitat requirements, metapopulation dynamics,
species interactions, etc. to predict the probability
of persistence of a population for a given time and
- Minimum viable population- population size
necessary for long-term persistence in an area.
- Technique is used for restoration planning and
for endangered species recovery plans.
• apply a management approach to restoration
that experimentally evaluates the success of
an ongoing project and modifies the
strategy accordingly. Marries applied
science with pure science.