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When planning a restoration, need to plan around NATURAL drivers and HUMAN caused drivers
- Natural drivers:
- 1.Variation in environmental conditions
- 2.Disturbances: stoicastic events
- Human caused drivers:
- 4.Habitat conversion
- 6.Species introduction
- 7.Climate change
Restoration plan needs to be SMART!
- Specific: what should change, avoid vagueness
- Measurable: how much change to expect
- Achievable: realism vs risk taking, real life assessment of the limits
- Reasonable: what can be done given the CONSTRAINTS
- Time bound: sequence of events, set MILESTONES for success
2 Important THEORIES in Community assembly:
- 1. Niche Assembly theory: Competition is the main force of structuring community (NOT random Immigration)
- Nitch OVERLAPS create the competition among species, with only one species satisfying each niche
- Two rules (Diamond):
- =1. Forbidden species combination
- =2. Reducing the niche overlap
- 2. Dispersal Assembly Theory: Random chance, dispersal and history is the main driving force for community assembly
- A series of filters (below) + RANDOM chance filter the amount of species
- -Dispersal and immigration
- -abiotic factors
- -Species interactions
The extent which a LANDSCAPE aids in the movements among habitats to acquire resources is connectivity. Habitat loss can result in a decrease in connectivity due to the movement from one patch to another requiring more energy or physiological activity than the individual can, or because the distance it must travel may be hazardous ( may contain barriers, such as predators). Lost connectivity is a primary reason that species which exist as metapopulations go extinct.
- Some species that have many individual populations require immigration levels among a NETWORK OF PATCHES. These patches may experience LOSSES due to periodic Diseases, Natural Disasters or Insufficient Resources. Each Patchwork is a subpopulation, with the whole community of all patches termed the METAPOPULATION.
- The Distance b/w each patch: Rescue effect
- The Size of the patch: Target effect
- These variables are able to determine if colonizers will find it (they will if the patch size is high).
- If the patches are far apart, the colonization chance is lower
- Species enrichment is highest on the LARGER island with NEARER patches (refer to graph, with max # of species on x-axis, and rate of immigration on y-axis
- If islands closer together, immigration rates will increase
- If island is larger, will be able to take in more species (increase diversity)
- Invasive species: may have potential to outcompete native species, or negatively impact other species in the habitat through consuming their resources or altering soil chemistry, for example.
- Hybrid vigor: can occur as well, when interbreeding between introduced species and native species result in hybrids which have a competitive ADVANTAGE over one or both of the parents
- Species interactions:
- Mutualism: BOTH species can benefit from their interactions
- Commensalism: One benefits and the other is NOT HARMED
Ecological Theory example
Recovery pathways: such as hysteresis model(diff path), humpty dumpty (not quite to pre-degraded state) or RUBBER band(same path backwards)
- Cookbook: Apply SAME Restoration projects as other projects to get same expected result as seen in previous restoration
- Carbon Copy: Maintains that we can create the ecosystem which is the SAME AS IT WAS IN THE PREVIOUS STATE. But ecosystems are NOT STATIC, but always changing. Sometimes invasive species or non-natie species are now part of a system and removing it will create a more detrimental effect, leading to less restoration. Restorations have various SUCCESSIONS that may lead to VARIATIONS from ideal state