Mangroves
From coraldigest
Mangroves
What are Mangroves?
- Groups of trees and shrubs that live in the coastal intertidal zone
- 80 different species (from shrubs to 200-foot-high trees)
- Slow moving waters allow fine sediments to accumulate and build up the muddy bottom
- Some have dense tangles of prop roots or buttresses that allow the trees to handle the daily rise and fall of tides
- Some have snorkel-like roots called pneumatophores that stick out of the mud to help them take in air
Where are They Found?
- Only grow at tropical and subtropical latitudes near the equator
- Grow in areas with low-oxygen soil
- Most in Southeast Asia, many in Florida
What Benefits Do They Offer?
- Stabilize the coastline, reducing erosion from storm surges, currents, waves, and tides
- Intricate root system is attractive to fish and other organisms seeking food and shelter
- Nursery for commercially important juvenile fish
- Habitats for oysters, crabs, shrimp, and birds
- Carbon sequestration and storage, decreasing the effect of global warming
- Stabilize shorelines and prevent erosion
- Buffer against hurricanes and tropical storms
- Mangroves intercept pollutants and land derived nutrients before they contaminate deeper water
- Nutrient transport from land to estuaries is one of the main agents of ecological change in coastal areas
What are the Stressors of Deforestation?
- Estimated that at least half of the world’s mangroves have been lost and continue to be destroyed at a rate of about one percent per year
- Stressors
- Coastal development driven by tourism and growing populations
- Aquaculture, particularly shrimp farming
- Mariculture has been reported as responsible for 50% loss of mangroves in the Philippines and 50-80% in Southeast Asia
- These ponds often have short life spans due to toxin accumulation and sulfide acidification, causing these pond owners to move to a new section of mangrove, furthering the destruction of mangrove forests
- Agriculture run-off carrying pesticides and herbicides
- Man-made changes in tidal or river flow that starve the system of sediment input
- Sea level rise
What are the Side Effects of Deforestation?
- Loss of mangroves reduces the amount of carbon sequestration possible and releases carbon stored in the soils, worsening the greenhouse effect
- Coastal communities left unprotected from storms and hurricanes
- Deforested shorelines are subject to greater rates of erosion and are unable to keep pace with sea level rise
- One of the world’s most threatened tropical ecosystems with global loss exceeding 35%
- In Americas, mangrove deforestation is 2,251 km2 per year, which is higher rate than tropical rainforest deforestation
- There is a pattern of reduced mangrove forest area for nearly all countries containing them, especially countries with large mangrove areas
What lives in the Mangroves?
- Birds roost in the canopy
- Shellfish and organisms attach themselves to the roots, such as barnacles, oysters, crabs, sponges, anemones
- Snakes and crocodiles hunt there
- Nectar source for bats and honeybees
- Juvenile fish find shelter there during there vulnerable first weeks
What are the Common Types of Mangroves?
Red Mangrove
- Grows along the edge of the shoreline where conditions are harshest
- Tangled, reddish prop roots and gray bark over a dark red wood
- Grows to heights of 80 feet
- Clusters of white flowers bloom during the spring months
Black Mangrove
- Long horizontal roots with pneumatophores
- Bark is dark and scaly
- Grows to heights of 65 feet
- White flowers blossom in spring
White Mangrove
- Occupying higher land than the Red and Black Mangroves
- No visible aerial roots, but can develop peg roots
- The least cold tolerant
- Grows to heights of 50 feet
- Produce greenish-white flowers in spikes in spring
Buttonwood Mangrove
- Found in the upland transitional zone
- Sensitivity to frost
- Button-like appearance of the flower heads that grow in branched clusters, forming cone-like fruit
How Are They Linked to Coral Reefs?
- Provide nutrients to neighboring ecosystems such as coral reefs and sea grass beds
- Nearby coral reefs suffer further pressure from sedimentation when mangroves are removed and can no longer filter the water
- Mangroves in the Caribbean have a strong influence on the fish populations in reefs near them
- The largest herbivorous fish in Atlantic, Scarus guacamaia (rainbow parrotfish), is dependent on mangroves and has become locally extinct when they are gone
- Decreased amount of herbivores will cause reefs to become less resilient to algal overgrowth
- Fisheries productivities are likely to decrease without mangroves
- The largest herbivorous fish in Atlantic, Scarus guacamaia (rainbow parrotfish), is dependent on mangroves and has become locally extinct when they are gone
- In a study in Belize comparing mangrove-scarce reefs to mangrove-rich reefs, the biomass of nearly every fish studied was much greater in the mangrove-rich areas
- Biomass of the blue striped grunt on patch reefs in the mangrove-rich area increased by 2667%
- Biomass of all 6 species studied in the patch reefs increased from 191% to 2667% in mangrove-rich areas
- Mangroves act as intermediate nursery between seagrass beds and patch reefs
Sources
1. http://ngm.nationalgeographic.com/2007/02/mangroves/warne-text/6
- National Geographic Article
- Published February 2007
- By Kennedy Warne
2. http://www.habitat.noaa.gov/abouthabitat/mangroves.html
3. http://www.flmnh.ufl.edu/fish/southflorida/mangrove/profiles.html
4. http://www.nature.com/nature/journal/v427/n6974/full/nature02286.html#f1
- Nature
- Volume 427 Number 6974
- Mangroves Enhance the Biomass of Coral Reef Fish Communities in the Caribbean
- pages 533-536
- Published February 5th, 2004
- By Peter J. Mumby, et al
- Bioscience
- Volume 51 Issue 10
- Mangrove Forests: One of the World’s Threatened Major Tropical Environments
- pages 807-815
- Published October 2001
- By Valiela, I ; Bowen, JL ; York, JK