Lecture 1: Ecology of MPAs & State of the Seas (jan 5) Flashcards
Important things to focus on when thinking about water rather than terrestrial environments.
Water has:
- buoyancy
- viscosity
- specific heat capacity
- oceans are patch - resources are not spread evenly
How does population ecology work?
Birth + Immigration >_ Death + Emigration
Dispersal (3)
- what is it?
- what type of process?
- What is it essential for?
- movement of an individual or group of individuals away from a parent population
- biological process
- essential for population stability + maintenance
Dispersal Mechanisms
Different life history traits
- adult dispersal
- broadcast spawning
- larval dispersal - planktonic behaviours
Pelagic Larval Duration
- Length of time larvae spend in the water column
- affects dispersal distance
- Planktotrophic - feed in water column - typically seen in invertebrates
- Lecithotrophic - rely on internal stores for energy - typically seen in fish and some invertebertes
Dispersal Advantages
- decreased competition between adults and their larval populations in the same physical space
Connectivity
- flux of any type of material between locations
- an interaction between species and landscapes
- should result in the exchange of genetic material between populations
- marine connectivity far greater than in terrestrial habitats
The importance of Connectivity (4)
- connecting adult populations with breeding or nursery sites
- connecting source and sink populations
- preventing inbreeding and maintaining genetic variation.
- accommodating range shifts.
Barriers to Connectivity
- changing currents
- habitat fragmentation
- Physical thresholds: - temperature, depth, salinity, substrate.
When do trophic cascades occur?
Trophic Cascades occur when predators limit the density and/or behavior of their prey and thereby enhance survival of the next lower trophic level.
The perfect MPA (3)
- Sustain population within protected region
- coverage of all biogeographic regions - including transition regions - easier to monitor species shifts here
- allow protected populations to do well enough to help populate areas outside MPA.
Predicted impacts of MPAs to..
- Fisheries?
- Biodiversity?
Fisheries
- increased in biomass of reproductive adults
- increased spill over into non-reserve areas.
Biodiversity
- increase in organism size and diversity.
Designing MPAs
- What is the overall goal?
- Ecological Characteristics
- Anything else?
- Overall goal is important:
- Fishery? Species of Consern? Important Habitat?
- Ecological characteristics
- dispersal
- connectivity
- site specific factors
_ Social considerations
Goal for the MPA
- What does the goal do?
- the goal will define the ecological processes necessary to protect
- very important to establish early on and consider the ecological process, habitat and/or species to be protected
What effects the design of reserves?
- essential areas - placement
- population of concern
- size
- spacing
What are some essential areas to protect? 5
- vulnerable life history stages
- aggregation grounds
- migration bottlenecks
- areas with high habitat heterogeneity
- areas of high diversity
SLOSS
- in terms of size what works best for protecting the diversity of species?
Single large or several small
- now known that a variety of sizes works best to protect the diversity of species and life history characteristic.
Connectivity and MPAs
- two reasons…?
- Sustain genetic diversity
- organisms inside the reserve have to impact organisms outside the reserve
issues with current ecology (2)
- poor understanding of the actual dispersal abilities and connectivity - Difficult to track larvae and species over space and time.
- its easier to maintain diversity than restore it
What cant MPAs protect from - or are not very good at?
- Climate change
- ocean acidification
- sea temperature rise
- sea level rise
- Sedimentation
- Pollution
- Marine disease outbreaks
- Conflicting goals
- Overly degrades systems
Take Home Message
- what about understanding ecology?
- What about MPA sizes?
- what about reserve networks?
- What do MPAs increase?
- Understanding the basic ecology is essential - fundamental process
- Any sized MPA has its advantages - bigger is better (most of the time) - need a diversity of sizes.
- Reserve networks often more effective than single reserves.
- MPAs increase:
- diversity
- size
- stability
Top 7 threats to the oceans?
- overfishing
- climate change
- invasive species
- pollution
- acidification
- habitat loss and destruction
- coastal development
Overfishing?
- Three major shifts in commercial fishing?
- Three major types of ecosystem damage?
Shifts in Commercial Fishing:
1 - Demersal
2 - Geographic
3 - Bathymetric
Three major types of ecosystem damage
1 - Species are depleted
2 - Habitat alteration
3 - Ecological shifts from removal of important species
Fishing down the food web? (2)
1 - Overall decline in bigger fish and top predators worldwide.
- after we fish out the bigger, higher trophic level fisheries, we target smaller and lower trophic level fisheries.
2 - Overall effort in wild capture fisheries has increased.
- can catch fish in more places in ocean at all depth now.
Global trends in fisheries (4)
- increasing global coverage
- increasing catches
- increasing effort
- declining catch per unit effort.
Sources of Pollutants?
Results of Pollution?
Sources:
- Ocean Dumping
- Run-off and point source pollution
- marine transportation
- atmospheric pollutants
- deep sea mining
Results of pollution:
- acidification
- eutrophication
- plastics and debris
- toxins
Our shifting perspectives on the oceans 5 lessons
1 - Perspective is getting longer - we know we can change the oceans.
2 - Species do not always recover after depletion.
3 - Ecosystems can be shifted into alternate states.
4 - Species are at risk of extinction - habitat loss and transformation.
5 - The deep sea is not beyond harm.
