1. Global Status & Conservation Challenges
Seagrass:
Global Status & Conservation Challenges
Len McKenzie
James Cook University, Cairns, Queensland, Australia

2. What are seagrasses? a functional group of marine flowering plants
photo courtesy Ria Tan
photo courtesy Ria Tan ♀
a functional group of marine flowering plants
are tidal or subtidal
have light sensitive leaves
have a true root system
have an internal system of veins
produce flowers, fruits and seeds
have important ecological roles

3. Provide many important services
nutrient filter
Provide many important services
food for dugongs
nursery/habitat for fisheries
coastal protection
food for sea turtles
blue carbon
disease mitigation

4. Global decline of seagrass meadows
Problem
Global decline of seagrass meadows
Approximately 58% of seagrass meadows globally, have lost part of their distribution
According to reports, the documented losses in seagrass meadows globally since 1980 are equivalent to two football (soccer) fields per hour
Waycott et al (2009) PNAS 106(30): 12377–12381

5. Many challenges local & regional recognition of seagrass importance
up-to-date information on status & condition
identifying threatening activities at local scales
balancing the needs of resources users with conservation, economic growth and food security
scientific research to support conservation actions

6. Seagrass extent poorly mapped in the Dugong Range States
Seagrass meadows range in size from a few square meters to thousands of square kilometres. Maps of seagrass distribution are either individual observations (points) or measured areas (polygons). As polygon maps provide the only quantitative measure of spatial extent, they are used exclusively for areal estimates. Point data was used only to indicate seagrass presence.
Globally (208 countries) mapped (polygon data only) 325,178 km2
but estimated to be up to 600,000 km2
species extent
TOTAL (46 states) 22 (24?) 161,496 km2
Pacific Islands (5) 11 (13?) 2,444 km2

7. Seagrass mapping inconsistencies & lack of standardisation
Data includes maps from various times, of various scales (ranging from 1:1,000 to 1:28,510,000), from variable sources, and ranging from anecdotal (no documented/visual evidence) to accurate field validation.
Although detailed, the database remains incomplete, as not all researchers and/or agencies contribute data.
Country spp coastline (km) extent (km2)
New Caledonia 11 2,
Palau 14 1,519 80
Papua New Guinea 13 5,
Solomon Islands 10 5,
Vanuatu 13 3,132 1, ??

8. agricultural/logging runoff industrial/urban runoff overfishing
Need to identify the threatening human activities at local scales
Direct, e.g.,
coastal development
dredging
netting
courtesy
Indirect, e.g.,
agricultural/logging runoff
industrial/urban runoff
overfishing
In order to manage seagrass we need to have a detailed knowledge of the impacts at local scales, both those impacts that are direct and often simple to identify, and those that are indirect and not as readily obvious as the activities that result in such impacts happen in locations often far removed from the meadow itself.
courtesy V.Balaji.OMCAR Foundation

9. Standardised mapping & monitoring
Seagrass-Watch:
scientists partnering with local stakeholders
Victoria (Australia)
Queensland (Australia)
Japan
NSW (Australia)
Papua New Guinea
Fiji
Pohnpei (FSM)
Kosrae (FSM)
Solomon Islands
Palau
Caribbean
Florida (USA)
Philippines
New Caledonia
California (USA)
Eritrea
Sabah (Malaysia)
Singapore
Johor (Malaysia)
China
Bangladesh
Thailand
Indonesia
Western Australia
Wales (United Kingdom)
Spain
Viet Nam
India
Comoros
Maldives
Kuwait
Myanmar
Seychelles
education only
<3yrs monitoring
>3yrs monitoring

10. Seagrass Spotter citizen science entry-level novice
Spotted by E Mayhead on 17th January 2017 in Lajas, Puerto Rico
Sighting Information:
Thalassia testudinum
Observed: Snorkelling
Observed: Subtidal
Coverage: Large area of continuous seagrass (>50m²)
Flowers: None
Sediment: Pebbles
Algae Coverage: 0%
novice

11. Balancing the needs of resources users with conservation, economic growth and food security
We having growing evidence of the value of seagrass meadows in supporting the livelihoods, food security and poverty alleviation of communities around the world. A recent study that I have led reveals that fishing activity exists wherever there is seagrass and people.
These values need to be maintained and their sustainability improved, this needs to happen with a backdrop of species and habitat conservation, growing economic development, and the problems faced by climate change. This is by far our biggest future challenge for seagrass conservation.
Singapore, Mozambique, Indonesia, Indonesia, Thailand, China, Mauritania, Wales