The study of the interactions of an organism or species with the living and non-living factors of the environment
(Growth and Survival Traits) (RED) What Traits distinguish one species from another?
i. Growth rate ii. Lifeform iii. Life span iv. Biomass allocation v. Ability to withstand environmental conditions vi. Rooting depth vii. Photosynthetic pathway viii. Nitrogen fixation ix. Mycorrhizal host x. Phenology
A species that has a disproportionate effect on the environment relative to its biomass
May structure ecosystems, determine the types and numbers of other species in a community
Examples? Predators can greatly effect prey behavior
(RED) What is a trophic cascade?
Occur when predators reduce the abundance of their prey, thereby releasing the next lower trophic level from predation
“What if the sea otters disappear?”
Greatly simplified food web…Nothing is eating the sea urchins so the urchins eat all the starfish and it continues on
What happened in Yellowstone (wolves)?
Wolves ate a lot of elk and the Aspen populations went back up.
The elk stopped browsing the riparian areas and moved into the uplands
Wolf population increased/ elk population decreased
How can predators effect landscape levels?
Wolves gone, more elks eating trees on river banks, river banks have increased erosion rates
Is wolf reintroduction passive restoration?
Advantages and disadvantages of this approach??????
(RED) What should be used as targets for restoration?
Many targets possible: All native species Mostly native species Pre-settlement (1850) composition Pre-European (1491) composition Pre-Native American (??) composition Pre-historic (13,000 BP) composition
How should we establish goals?
Based on ecological assessment
Also based on context: Social Cultural Economic Political Moral Aesthetic —————— Example: Carbon offsets
Must be established a priori
May or may not be historical
What are some non-historical restoration goals?
Non historical targets: % native species Diversity metrics: total vs. patch diversity Abundance of Focal species: rare or keystone species Ecological Processes: nutrient cycling, hydrologic attenuation
What are some challenges to setting goals
Incomplete information Uncertainty about future Industrial rates of change Ecosystems are complex Spatially and temporally dynamic Initial conditions matter
What do successful restoration models require?
May need sequential references with which to assess restored states
What is a restoration model?
Especially required for long-term goals
How can thinking about biodiversity guide restoration practice?
What are some of the causes of the necessity for dry forest restoration?
High Grade Logging
What are dry forest restoration objectives?
Plan and Treat and Multiple Scales
Build resistance to wildfire
Promote resilience to insect outbreak
Conserve Old-growth structure
Sustain local communities
Create and maintain management options
What are some dry forest restoration principles and their effects?
Increase height to live crown -> Requires longer flame length to begin torching
Decrease crown density -> makes tree-to-tree crown (fire less probable)
Keep big trees of resistant species -> Less mortality for same fire intensity
What is Clump distribution?
A major premise used in dry forest restoration
What are the most important strategic foci when deciding how to restore a dry forest area?
Clump size and distribution
Tree type choice
Decide whether or not to keep old trees
How to thin
Isolate certain species?
Preserve wildlife habitat?
Where does the cluster method work well (dry forest restoration)
Even aged stands with few old trees
high graded stands with some old trees
Where are cluster methods not useful? (dry forest restoration)
Stands with major tree health issues
Stands of where most of desired density is comprised of old trees
What are the three elements of biodiversity?
(RED) How relevant are biodiversity elements (Structure, Composition, Function) as restoration goals?
STRUCTURE: Variables are: Easy to measure Static (don’t change quickly)
A common restoration criterion Focus on mean values and, increasingly, range of variation
Might reflect particular site differences Ignores mechanisms that maintain structure
COMPOSITION: Variables are: Somewhat easy to measure (need ID skills) Fairly static (don’t change quickly)
A common restoration criterion
Ignores mechanisms that maintain composition
FUNCTION: Variables can be: Difficult to measure (e.g., CO2 flux) Dynamic – fluctuate spatially and temporally
Need to choose the right variable!
Requires strong understanding of ecosystem
Why is Function unique in comparison to Structure and Composition? (Biodiversity?
More generic than structure or composition E.g., same process can occur with different suites of species More relevant in light of climate change?
Often assumes that structure and composition will develop once processes are ‘fixed’ E.g., estuarine restoratio
What would define a structural approach (biodiversity) to removing trees in a project?
Decide on desired forest structure (e.g., using reference data)
Compare extant and desired structures to develop thinning prescription: How many trees to cut Which sizes of trees to cut
Model how ecosystem process (fire behavior) responds to treatment
What would define a compositional approach (biodiversity) to removing trees in a project?
Favor some species over others E.g., Retain fire-tolerant species, remove fire-sensitive species
Not a primary focus in SW: Forest contains few tree species Tree species present haven’t changed greatly
What would define a functional approach (biodiversity) to removing trees in a project?
Decide on desired fire behavior
Model fire behavior under various stand management alternatives: How many trees to cut Which sizes of trees to cut
Choose simplest alternative that achieves desired fire behavior
Measure resulting forest structure
(RED) What is a keystone species?
A species that if removed will greatly alter the environment.
It has a disproportionate effect on the environment relative to its biomass
(RED) What is a keystone process?
A process necessary to the balance of an environment. Removal or alteration will guarantee a shift in the environment.
(RED) How does fire work as a keystone process?
Rationale: Forests were maintained in an open state by fire
Fire is missing now, so let’s put it back
(RED) What are reference dynamics?
Example: fire frequency
Are approaches to biodiversity exclusive?
No they are interchanging and usable in coexistence
What are the scales of biodiversity?
Genetic Population / species Community / ecosystem Landscape
(RED) How do the scales of biodiversity matter in restoration?
GENETIC: How much genetic variation do you want in planting stock? Horticulture: little Restoration: lots
Clonal plants: very little genetic variation
Adaptation to site
POPULATION / SPECIES For a given species: Where to plant it? Clustered? Evenly distributed? How many to plant? When to plant it? All same age, or in cohorts?
COMMUNITY / ECOSYSTEMS Which species to plant together? Relation between species and environmental conditions E.g., wet habitats Interactions – pollinators, etc.
Scale that receives most attention during restoration
Relation of restored areas to matrix Energy and nutrient flows Distribution of patches Edges Connectivity
How / why do disturbances matter for restoration?
What is a disturbance?
A relatively discrete event in time that disrupts ecosystem, community, or population structure and changes the resource, substrate availability, or physical environment
(RED) Examples of disturbances? Abiotic Biotic Anthropogenic
Why do disturbances differ?
Ecological legacies Historical contingency Resource availability Frequency Patch size Specificity Pattern and process
What is an ecological legacy? (Disturbances)
the living organisms, dead organic matter, and the physical structures … that remain after disturbance
What is historical contingency (Disturbances)?
Is a disturbance within the range of variation of historical disturbances?
Define resource availability (Disturbances)
More productive sites have more resources We can alter productivity
What is frequency (disturbances)?
Depending on the ecosystem, increases or decreases in frequency can cause problems
How does patch size play into disturbances?
Large patch Regeneration succession
Small patch(es) Patch dynamics Little change in composition
Heterogeneity of disturbance effects increases species diversity
What is specificity (disturbances)?
Who is affected? Species Age Size Health
What are the three themes of disturbances and which disturbances fall into each category?
Ecological legacies Historical contingency
Resource availability Frequency
Patch size Specificity Pattern and process
How do disturbances apply to restoration?
Restoration often (always?) involves intentional disturbances
Appropriate’ disturbances depend on: ecosystem restoration goals
(RED) How can disturbance ecology inform restoration projects?
Are site physical conditions appropriate relative to restoration goals? Are invasive species present? Do desired species need to be planted? How similar is disturbance to historic ones in this ecosystem?
Are resource levels appropriate? More productive sites often have more plant growth – especially by ‘weedy’ species – and faster growth rates Some species are disturbance-dependent
Disturbance characteristics affect community composition and structure How often is disturbance required? Do disturbances target particular species? Eg, selective herbicide use Eg, fires to kill fire-sensitive species
What are the three categories of disturbance resistance?
Stable: able to return to starting value
Resistant: changed little by disturbance
Resilient: easily altered but rapidly returns to starting value
(RED) Brainstorm examples of ecosystems that are stable in spite of disturbances
Background’ levels of bark beetles Drought in prairies Fire in fire-adapted systems Tides in intertidal zones
What type of disturbance is most likely to cause unstable ecosystem states?
Those not found in historical contingency
Is a disturbance within the range of variation of historical disturbances?
What is classical succession (ecosystem dynamics)?
Steady, directional change to a single equilibrium endpoint Goal = climax community
Based largely on species traits Competitive ability Stature Seed dispersal
Deterministic – easy to model High predictability
Implies that we just need to reverse the degradation Appropriate for minimally degraded sites Inappropriate for highly disturbed sites?
What are the three different views of ecosystem dynamics?
Classical succession State and transition Persistent non-equilibrium
Define state and transition (ecosystem dynamics)
Some ecosystems change rapidly: Crash of fishery stocks Woody plant invasion of grasslands
Little change until a threshold is crossed
Possible to have multiple equilibriums
What are the implications for restoration of state and transition ecosystem dynamics?
‘Fits’ some systems well (e.g., rangelands)
Implies more complex management than required by classical succession Moderate predictability
Need to understand thresholds
Initial conditions important
Management may require different actions than caused original transition
How would you restore shrubland to grassland?
What is Persistent non-equilibrium (ecosystem dynamics)?
Assumes external factors are more important than in other views: Stochasticity (random events) Past history (legacies)
Conceptual idea; difficult to ‘prove’ Difficult to distinguish from multiple equilibrium states
Relevant for urban settings?
What is meant by Manipulating Dynamics (ecosystem dynamics)?
Can achieve similar results by different activities at different spatial and temporal scales
Example: recovery of riparian vegetation in Yellowstone Option 1: plant lots of trees and shrubs, protect from browse Option 2: reintroduce wolves; elk stay out of riparian areas and vegetation recovers
Disturbances initiate or direct subsequent ecosystem dynamics
Models of ecosystem dynamics: Summarize our ‘view of the world’ Can guide restoration actions Take time and effort to evaluate
Contrast Stresses and Disturbances
Stress. Eg: Desert organisms are adapted to seasonal and yearly fluctuations in precipitation. Drought is not uncommon.
Disturbance: Eg. Fire, grazing, or extreme drought can affect soil quality and vegetation for many years
What are some values of arid desert landscapes?
Plant and animal species not found anywhere else Endangered species Indigenous food crops Plant-derived drugs and other chemicals from drylands Flood control, water purification, dust control, sustainable livestock use
What are threats to desert ecosystems?
Grazing Agriculture Roads Military activity Mining Recreation Pollution Changes to fire regime Invasive species Climate change
What are some abiotic limitations to desert restoration?
Loss of topsoil late-successional species fail when planted into early successional soils.
Moisture limitations Pulses of establishment with rain events
Landscape scale factors Eg. Restore low land with good soils, but if the slope above fails…
What are some biotic limitations to desert restoration?
Inoculation not possible for most species of microorganisms Weeds Arid systems tend to be open; disturbance adds new open spaces Animals Herbivory, trampling Biodiversity There are always more rare species than abundant species. Tradeoff between species that establish and stabilize the soil, but their longevity and competitive ability reduce return of native species.
What is the stress-gradient hypothesis? (desert restoration)
As abiotic conditions become more stressful, facilitation interactions become more common Facilitation is where one species’ structure or function benefits another species
Eg. In areas of lower precipitation, seedlings rely more heavily on nurse plants.
What are the two main aspects of community assembly?
Filters and Priority effects
What are the filters of community assembly?
DISPERSAL Species differ in dispersal ability Method Distance Barriers
ENVIRONMENT Species differ in environmental tolerances Shade Nutrients Moisture
DISTURBANCE: Species differ in reaction to disturbances: Type Frequency Duration
What are the implications of the filters of community assembly?
Species selection is one of the most important decisions made during a restoration Only a subset of species can ‘pass through’ the filters at a given site
Dominance generally by species that: Are already present at site: Extant vegetation Seed bank Arrive first
Describe the colonization/competition trade off
Competition/colonization trade-off Good colonists = weaker competitors Permits coexistence and species replacements
How can restoration control priority?
Site preparation to remove undesired species before planting
Adding species that would not colonize naturally or quickly
Do not need to assemble entire community at once Interseeding Coordinate species introductions with stages in ecosystem development E.g., UBNA – shade Expect some species to ‘phase out’ over time
What are the two main principles of restoration economics?
Economics deals with: Incentives Costs and benefits
Responsible party vs No responsible party (who should pay for restoration)?
RESPONSIBLE PARTY: Feasible for some point sources Those who caused damage Eg, fines for Deepwater Horizon spill Those who will cause damage Eg, Mitigation banking
NO RESPONSIBLE PARTY: How are funds raised? Taxes General Specific products or activities Volunteers – money and time Private property owners
Name some economic valuation methods
Replacement cost: Cost of restoring a damaged system
Replacement cost multiplier: Cost of restoring an ecosystem plus additional funding for lost values during damage and uncertainty
Valuing ecosystem goods and services: Evaluate economic benefits of restoring a given good or service using a tradeable substitute. E.G, watershed for restoration vs. a water treatment plant to improve water quality
Travel cost method
Hedonic price method
What are the three dimensions of commitment?
Affective: emotional attachment to, identification with, & involvement in volunteering
Normative: perceived obligation to volunteer
Continuance (Calculative): perceived cost associated with quitting volunteering
Why do people commit?
People continue to volunteer over long periods of time because they are committed to the cause! Volunteer retention efforts can benefit from understanding what motivates commitment Content of recruitment messages, Articulation of mission statements, Provision & organization of volunteering opportunities & settings
What are the 6 dimensions of motivations to volunteer?
Environment Socially interact Learning & Career Escape & Exercise Help community Ego Protection & Enhancement
Summarize commitment motivations and findings
Ego is an important predictor of initial participation—recruitment
Social interactions are important for particular organizations
Community is a strong predictor of commitment—enduring involvement—retention
Social factors are more significant predictors of participation & commitment to eco-restoration volunteerism Ecological motivations appear to moderate the effects of social interactions & community, but rarely so?