Summary Restoration Ecology
Lecture 1 | Introduction
Restoration: the process of assisting the recovery of an ecosystem that has been degraded,
damaged, or destroyed – Society of Ecological Restoration (SER)
Ecological restoration aims to recover the structure, biodiversity, and function of degraded
ecosystems
Human modification of terrestrial lands
Caused by anthropogenic factors like
agriculture, mining, transport etc.
→ very few areas not affected
Extinctions since 1500
Shown in grey area is the extinction rate without human
influence (natural process)
→ since 1900s an exponential increase in extinction rates
Next to an intrinsic value, nature provides us with ecosystem services
→ thus important to conserve nature
Change of ecosystems
Two forms of ecosystem change
- Linear change
- Non-linear change
Linear change: most simple for of change – over time an
ecosystem state might change, which goes in a straight line
Characteristics:
- Continuous states (A, AB, B, etc.)
- No sharp boundaries
- Gradual response to disturbance
, Convenient from a restoration perspective
With an increasing amount of disturbance/stress an
ecosystem gets degraded
If stress is removed, it brings the system closer to the intact
site
e.g. natural succession as linear change
Start with bare soil patches, over time pioneer species colonize the soil
which root and develop SOM which makes it suitable for other species
→ Things in nature are often not as simple
Non-linear change (thresholds): while a disturbance
increases the ecosystem condition stays more or less
stable, until a certain threshold is reached which creates a
sudden shift into a degraded system
Characteristics:
- Sharp boundary between states, less sharp
environmental boundary
- Discrete states (A, B, C)
- Response to disturbance: resilient, then big
change
Thresholds in restoration
- Biotic: Species * Species
o Presence dominant competitive (exotic species)
o Predation/grazing pressure too low or too high
o Absence facilitating species (e.g. pollination )
- Biotic: Species * Landscape
o Suitable area cannot be colonized
o Area too small to host healthy population
o Landscape does not match species (multi-habitat use within and between life stages)
- Abiotic
o Resource-related (nutrients, water, light)
o Non-resource (microclimate, toxic contaminants)
, Compositional heterogeneity: amount of different habitats
Configurational heterogeneity: measure in more intermingled habitats
Usually with the increase of heterogeneity the
amount of species in an area increases.
However, due to area-heterogeneity trade-off,
more heterogeneity means that some habitats
get smaller
→ species with narrow niche width (specialists)
are more susceptible to extinction
Ecosystems can experience different thresholds over the
course of change
→ in general biotic thresholds are less severe (easier to
overcome) than abiotic thresholds
E.g. Temperature woodland in Canada
Sørenson Coefficient of Similarity: 1 = 100% of
similar species composition restored vs reference (=
ultimate goal)
Roads were removed from a woodland to restore the area. It increased the
SCS, but only to 0.4 (only 40% of the original state is restored). Which can be
explained by the missing of dispersal-restricted species like ants, that
disperse seeds within close range.
, Restoration: systematic approach
1. Choose target: reference situation: historical, current potential/possibilities
2. Mechanism (causes): why did it disappear?
3. Biotic or abiotic thresholds: Key habitat, Soil chemistry?
4. Configuration landscape: size reserve, connectivity, elements, hydrology
5. Source population: animals, seed bank
6. Approach restoration: intervention, legislation, communication
7. Chance sustainable restoration: N deposition, current land use
8. Current/ follow-up management: type, intensity, timing
9. Monitoring: is the target reached, if not why not
Choose target
- Historical reference: restore vegetation that was previously there
o Advantage: perhaps rest population present, high chance that it fits in landscape
o Disadvantage: possible that large effort is needed to change current situation
- Current potential/possibilities: e.g. restoring agricultural lands to a little bit more flower rich
o Advantage: cheapest, least disturbance
o Disturbance: less species rich
→ important to look at the objective
(e.g ecosystem services, intrinsic value)
→ important to look at the personal image of the landscape
(wilderness, arcadia)
Mechanisms, thresholds, landscape
LESA: landscape ecological system analysis
Lecture 1 | Introduction
Restoration: the process of assisting the recovery of an ecosystem that has been degraded,
damaged, or destroyed – Society of Ecological Restoration (SER)
Ecological restoration aims to recover the structure, biodiversity, and function of degraded
ecosystems
Human modification of terrestrial lands
Caused by anthropogenic factors like
agriculture, mining, transport etc.
→ very few areas not affected
Extinctions since 1500
Shown in grey area is the extinction rate without human
influence (natural process)
→ since 1900s an exponential increase in extinction rates
Next to an intrinsic value, nature provides us with ecosystem services
→ thus important to conserve nature
Change of ecosystems
Two forms of ecosystem change
- Linear change
- Non-linear change
Linear change: most simple for of change – over time an
ecosystem state might change, which goes in a straight line
Characteristics:
- Continuous states (A, AB, B, etc.)
- No sharp boundaries
- Gradual response to disturbance
, Convenient from a restoration perspective
With an increasing amount of disturbance/stress an
ecosystem gets degraded
If stress is removed, it brings the system closer to the intact
site
e.g. natural succession as linear change
Start with bare soil patches, over time pioneer species colonize the soil
which root and develop SOM which makes it suitable for other species
→ Things in nature are often not as simple
Non-linear change (thresholds): while a disturbance
increases the ecosystem condition stays more or less
stable, until a certain threshold is reached which creates a
sudden shift into a degraded system
Characteristics:
- Sharp boundary between states, less sharp
environmental boundary
- Discrete states (A, B, C)
- Response to disturbance: resilient, then big
change
Thresholds in restoration
- Biotic: Species * Species
o Presence dominant competitive (exotic species)
o Predation/grazing pressure too low or too high
o Absence facilitating species (e.g. pollination )
- Biotic: Species * Landscape
o Suitable area cannot be colonized
o Area too small to host healthy population
o Landscape does not match species (multi-habitat use within and between life stages)
- Abiotic
o Resource-related (nutrients, water, light)
o Non-resource (microclimate, toxic contaminants)
, Compositional heterogeneity: amount of different habitats
Configurational heterogeneity: measure in more intermingled habitats
Usually with the increase of heterogeneity the
amount of species in an area increases.
However, due to area-heterogeneity trade-off,
more heterogeneity means that some habitats
get smaller
→ species with narrow niche width (specialists)
are more susceptible to extinction
Ecosystems can experience different thresholds over the
course of change
→ in general biotic thresholds are less severe (easier to
overcome) than abiotic thresholds
E.g. Temperature woodland in Canada
Sørenson Coefficient of Similarity: 1 = 100% of
similar species composition restored vs reference (=
ultimate goal)
Roads were removed from a woodland to restore the area. It increased the
SCS, but only to 0.4 (only 40% of the original state is restored). Which can be
explained by the missing of dispersal-restricted species like ants, that
disperse seeds within close range.
, Restoration: systematic approach
1. Choose target: reference situation: historical, current potential/possibilities
2. Mechanism (causes): why did it disappear?
3. Biotic or abiotic thresholds: Key habitat, Soil chemistry?
4. Configuration landscape: size reserve, connectivity, elements, hydrology
5. Source population: animals, seed bank
6. Approach restoration: intervention, legislation, communication
7. Chance sustainable restoration: N deposition, current land use
8. Current/ follow-up management: type, intensity, timing
9. Monitoring: is the target reached, if not why not
Choose target
- Historical reference: restore vegetation that was previously there
o Advantage: perhaps rest population present, high chance that it fits in landscape
o Disadvantage: possible that large effort is needed to change current situation
- Current potential/possibilities: e.g. restoring agricultural lands to a little bit more flower rich
o Advantage: cheapest, least disturbance
o Disturbance: less species rich
→ important to look at the objective
(e.g ecosystem services, intrinsic value)
→ important to look at the personal image of the landscape
(wilderness, arcadia)
Mechanisms, thresholds, landscape
LESA: landscape ecological system analysis
