Habitat restoration

Question 1

What % of oyster reefs were lost globally?

Answer 1

85%

Question 2

What % of estuaries are oyster reefs functionally extinct in?

Answer 2

37%

Question 3

What are the causes of habitat loss?

(5)

Answer 3

Overfishing, Eutrophication, Coastal development sewage inputs, Sedimentation, Habitat disturbance

Question 4

What are the benefits of habitat restoration?

(5)

Answer 4

Boost local fish and crustacean fisheries,
Improve water quality,
Protect shorelines by reducing coastal erosion,
Improve estuary condition,
Oyster reefs support higher biodiversity and abundance of species

Question 5

What are the roles of oyster beds?

Answer 5

Filters water, remove nitrogen, sequester carbon, provide habitats, feed on algae and phytoplankton where gills act as sieve to remove contaminants.

Question 6

What is the Solent Oyster Restoration Project?

Answer 6

In 1978, 15 million oysters were removed from the Solent.
In 2013, the fishery collapsed and oyster fishing was banned due to failure to reproduce.
Native oysters are now classed as a priority species in UK’s Biodiversity Action Plan. Over one billion larvae were released into the Solent from oyster nurseries in 2017 alone, 105,000 oysters restored into nurseries or onto the seabed.

Question 7

How does an oyster hatchery operate?

Answer 7

1. Uses local oysters at correct temperature and diet, in close confinement so they will breed.
2. Allow larvae to settle on old oyster shells.
3. Placed mature ‘brood stock’ oysters at high densities in cages hung in the water beneath pontoons, facilitating the release of millions of larvae into the Solent.

Question 8

What is the Chesapeake Bay Oyster Restoration?

Answer 8

Oyster Crassostera virginica supported large fisheries in Chesapeake Bay but overfishing and pollution led to a decline.
In 2004, Army Core of Engineers constructed 42 ha oyster reef by placing dredged oyster shells, resulting in 180 million oysters.
From 2012-2016, 142 ha in Harris Creek, costing $28 Million, where no commercial fishing allowed.

Question 9

What defines a successfully restored tributary?

Answer 9

50 to 100% of the currently restorable oyster habitat has oyster reefs that meet the reef-level metrics.
8 to 16% of historic habitat has oyster reefs that meet the reef-level metrics.

Question 10

What are the criteria for a successfully restored reef?

Answer 10

A minimum threshold of 15 oysters and 15 g/dry weight/m2 covering at least 30% of the target restoration area at 6 years post-restoration;
A target of 50 oysters and 50 g/dry weight/m2 covering at least 30% of the target restoration area at six years post restoration;
Two or more oyster year classes present; Stable or increasing spatial extent, reef height, and shell budget.

Question 11

What is the aim of the Solent Seascape Project launched in 2022?

1,4

Answer 11

Aim to protect and restore 30% of the Solent’s habitat, actively restore 8 Ha of saltmarsh, 7 Ha of seagrass, 4 Ha of oysters and 10 breeding seabird nesting sites.

Question 12

What is blue carbon?

Answer 12

The carbon stored in the biomass and sediment of blue forests.

Question 13

What are blue forests?

Answer 13

Coastal and marine ecosystems that sequester carbon and provide ecosystems such as mangroves, seagrass, and saltmarshes.

Question 14

What are the types of ecosystem services?

Answer 14

Provisioning: food production, water, wood and fibre, fuel.
Supporting: nutrient cycling, soil formation, habitat provision.
Cultural: spiritual, aesthetic, educational, recreational.
Regulating: climate, flood, water purification.

Question 15

What are the ecosystem services of blue carbon?

Answer 15

Store and sequester carbon, Food security, Recreational opportunities, Shoreline protection, Biodiversity.

Question 16

What % loss of global mangrove coverage occurred from 1980-2000?

Answer 16

35%

Question 17

What are the benefits of mangroves?

Answer 17

Nursery habitat and refuge for fish and invertebrates, energy dissipation for shoreline protection, nutrient filtration.

Question 18

What has seagrass monitoring found?

Answer 18

Decline in canopy structure and biomass, shorter and narrower leaves, change climate to pioneer species.

Question 19

What % of seagrass loss occurred in the UK?

Answer 19

~84-92%

Question 20

What % of global loss of mangroves occurred per year since 1990?

Answer 20

7%

Question 21

What was the rate of annual mangrove loss before 1940?

Answer 21

0.9%

Question 22

Why is seagrass important?

Answer 22

Create habitat corridors, support biodiversity, shelter for juveniles, store carbon, improve water quality, nutrient cycling, food and livelihoods.

Question 23

What are the causes of seagrass decline?

Answer 23

Physical disturbance, Turbidity, Nutrients/eutrophication, Wasting disease, Sea level rise and coastal erosion, Excess herbivory, Habitat loss.

Question 24

What % of the ocean is MPA and what is the aim by 2030?

Answer 24

~8%, 30% by 2030.

Question 25

What factors are monitored in MPAs?

Answer 25

Organisms type and quantity, Ecosystems, Movement, Vertical distribution, Fish stock population trends, Reproductive areas, Changes over time.

Question 26

Why are estuaries key for alien introductions?

Answer 26

Shipping hubs: Ballast water/fouling on hulls (major vector). Aquaculture imports: Oyster/mussel farming (e.g., Crepidula with Pacific oysters). Disturbed habitats: Human activity creates free niches for invaders.

Question 27

What are the biological features aiding establishment of estuarine invaders?

Answer 27

Euryhaline tolerance: Survive salinity swings (e.g., Styela clava). Rapid reproduction: Short life cycles (e.g., Hydroides larvae). Generalist diets: Exploit varied resources (e.g., Undaria outcompetes natives).