Ecosystem Management and Conservation Flashcards
What are communities?
Direct and indirect effects of competition, predation, and parasitism, with dominant and keystone species playing major roles.
How are ecosystems maintained by inputs of energy and nutrients?
Allochthonous - Receives a majority of nutrients from outside.
- Leaf debris from riverbank in stream communities.
- Rain of detritus to abyssal zone of oceans.
Autochthonous - Self-contained internal nutrient supply.
What is the large-scale study of ecosystems?
Landscape ecology
What are critical species interactions?
Keystone species interactions
- Predator
- Food resource
- Ecosystem engineer
Do we prioritize keystone species?
Not necessarily..
1. Keystone means different things to different people.
2. Different effects of keystone species
3. Focus on keystone could fail to protect other species
4. There is a range in strength of species’ effect.
The combination of some non-keystone species may have even greater effects.
How can overpredation affect diversity?
- Rare species are secondary prey
- By-catch
For a species to be of conservation concern what factors need to be in place?
Conservation threat to a species particularly due to predation, depends on the ecosystem in which it is found and that species resilience.
What is hyper-predation?
Top predators consume lower predators.
What is Apparent competition?
Where two species that do not directly compete affect each other indirectly by being prey to the same predator.
Provide some examples of apparent competition..
Study in Kenya on lion preyingon Zebra and hartebeest.
Zebras the priamry prey but lions select hartebeests.
What is a mesopredator release?
Removal of top predators can result in a linear trophic cascade -> increase in lower predators-> decrease in prey.
E.g. Iberian lynx in pain depredates Egyptian mongoose and rabbits.
What four conditions allow refuge from predation (bottom-up regulation)?
Body size - Small mammal species are vulnerable to predation.
Migration - Escape from predators/ access to ephemeral, high-quality food resources.
- Low diversity ecosystems- Single predator with one or a few prey species.
- Smaller ungulates experience more predation -> top-down regulation.
High diversity communities:
- Limitation of herbivore species determine by its place in the hierarchy of herbivores.
What are the ecosystem consequences of bottom-up processes?
Mammals may not be numerous compared to some animal groups, but their impact is considerable:
- Determine physical structure of habitats
- Alter rates of ecosystem processes such as nutrient flow, growth rate, and decomposition.
- Dictate species diversity.
What happens if different trophic species are lost?
Top carnivore -
Increase in abundance of small predators, overgrazing etc.
Large herbivore-
Habitat succession and reduced diversity
Pollinators & seed dispersed -
Reproduction & recruitment failure of certain plants
Parasites-
Population explosion of host species.
Mutualists with defensive properties
- Increased predation and disease of plants.
What are the different trophs within trophic levels?
Autotrophs
Heterotrophs
Why is disturbance important?
It can be Deterministic or Stochastic …
Fire- Intentionally caused by human activity (Deterministic)
- Naturally occurring wildfires.
Disturbance generates biodiversity.
What traits of species tend to be successful invaders?
- High reproduction rate- Short generation time.
- Long-lived
- High dispersal, broad range, and diet
- Habitat generalist
- Human commensal
What communities might be invadable?
- Early successional - less niche dense - not at equilibrium.
- Low diversity of native species
- Absence of predators or species ecologically similar to invader
- Absence of predators in history (Naive)
What can over abundance of native species cause?
Reduced natural diversity
Disease and parasite spread
Local extinctions
What are the four basic principles for good conservation management?
- Critical ecological processes must be maintained
- Ecosystem approach (best!)
- Focus on important species - External threat minimized and external benefits maximized
- Evolutionary processes must be conserved
- Management must be adaptive and minimally intrusive.
Provide examples of management at different scales.
Population -
Perform some population viability analysis to assess the minimum pop size needed for persistence.
Ecosystem -
Use prescribed fire to maintain levels of vegetation heterogeneity
Landscape -
Protect riparian wetlands from chemical runoff by placing buffer areas between agri-fields and wetlands.
What are the contrasts between traditional and ecosystem management?
Traditional -
- Focuses on economics and resource extraction
- Equilibrium perspective
- Prescription- command and control
- Site specificity
- Often confrontational - public seen as adversaries.
Ecosystem
- Emphasis on balance between Ecol processes and commodities, amenities
- Nonequilibrium perspective
- Acknowledges uncertainty and flexibility (adaptive)
- Attention to context
- Public invited as partners
How did the storm on south island in 1968 (The Wahine storm) Effect Black swans?
Beds of macrophytes were destroyed, which caused physical changes in lake sediment that prevented return.
Black swans dropped from 80,000 -40,000 to 10,000 and have not recovered.
What are the different terms used to encompass ecosystem functions?
Ecosystem processes, services and goods.
Name some examples of Ecosystem processes?
Hydrology
Biological activity
Bio-geographical cycling
Decomposition
Resilience
Robustness-fragility
Name some ecosystem services?
Maintaining hydrological cycles
Regulating climate
Purifying water and air
Pollinating plants
Cycling nutrients
Name some ecosystem goods?
Food and clean water
Construction materials
Medicinal plants
Wild genes
Replacement species
Biological control agents
Tourism
What is ecological restoration ?
Not harming the environment whilst identifying and deals with processes which have lead to degradation.
Determine realistic goals and measures of success.
Monitor the restoration and assess success.
What is a restoration process?
- Restore to ‘natural state’
- Create a system with favourable traits.
Outline succession.
- Habitat is disturbed - leaving residuals or legacies
- Animals and plants invade the area
- Species become established and interact (Competition, predator-prey etc)
- Often change the condition of a site
- Changes persist until a type of equilibrium is reached.
Much of restoration involves manipulation of succession.
What are the keys to a successful restoration project?
- Judgements - excellent data and ecological expertise.
- High social commitment (engagement)
- Ecological circumstances - less damage the better
- Values - biocentric or enlightened anthropocentric
