Mangrove Forest Ecosystems

What are Mangroves? Mangroves are plants that grow in tidal areas. The word mangrove can describe a single plant or it can refer to a whole community of plants. They are halophytes (‘salt loving”). Most plants can not survive in salty conditions; mangroves have adaptations to thrive here.

Where Do Mangroves Grow Where Do Mangroves Grow? What can you infer about mangroves by looking at this map?

Where do Mangroves Grow? Mangroves grow only in the tropics and subtropics. They do not tolerate cold temperatures well. Freezing temperatures will kill them.

Where do Mangroves Grow? Mangroves grow best in sheltered areas with low wave energies. High wave energies destroy the shallow root systems of Mangroves. Strong wave action also prevents seedling establishment and the build up of fine sediments they need for growth.

Stop and think! What impact do you think that hurricanes might have on a mangrove community?

Effect of hurricanes Hurricanes have a profound impact on Mangrove communities. Severe erosion and wind damage can severely restrict growth. In severe cases areas of mangroves can be destroyed. The picture shows damage to Florida mangroves by Hurricane Charley.

Did you know? There are about 100 types of mangrove plants around the world. This includes some palms and ferns. In Florida there are four main mangrove plants.

Types of mangrove in Florida Florida mangroves include 3 tree species. The Red mangrove The Black mangrove The White mangrove Each mangrove has its own level of salt tolerance and this determines its location.

The Red Mangrove Has tall arching roots called prop roots. These supply air to the underlying roots and provide stability. Found closest to the water as they have the highest salt tolerance. Dark green elliptical leaves, which are paler underneath.

Red Mangroves The pictures show the flowers of the red mangrove and also its leaves, seeds and developing prop roots. Notice that the prop root develops from the seed and grows downward.

Black Mangroves Black/brown bark Numerous breathing tubes called pneumatophores project from the soil beneath. Grows on high tide shores.

White Mangroves White mangroves are usually found upland of the red and black mangroves. The bark is pale and they do not have prop roots or pneumatophores.

Mangrove Adaptations All mangrove plants have special adaptations that allow them to survive in their salty environment. Their unusual root systems give them support and stability in the loose soil. There is little oxygen present in these soils and prop roots and pneumatophores allow them to get oxygen from the air.

Mangrove Adaptations Did you know that mangrove plants are unique in that they have live young (viviparous). The seed remains attached to the parents plant until it germinates. It then falls from the tree and drifts on the water until it finds somewhere to take root.

Mangrove Adaptations Mangroves can tolerate salt water and out-compete other plants. They excrete salt through pores in their roots and leaves.

Why are mangroves important? Mangroves are essential to the food chain. When the leaves fall into the water, nutrients are released that are needed for the growth of phytoplankton. Phytoplankton are the producers in this and most other oceanic ecosystems.

Why are mangroves important? The leaf detritus also provides food for animals such as: worms, snails, mussels, oysters, shrimp, clams and mullet.

Why are mangroves important? These detritus eating animals are a source of food for carnivores such as crabs and fish. These in turn provide food for larger fish, reptiles and birds.

Why are mangroves important? Mangrove wetlands provide: habitat, feeding, breeding and nursery areas… for a wide variety of plants and animals, including endangered species.

Wildlife in the Florida mangroves Pictures from left to right horseshoe crab, sheepshead, tree snail, mangrove water snake.

Mangrove wildlife pictures show from left to right: blue crab, blue heron, fiddler crab, mangrove snapper

Mangrove wildlife From left to right Florida fighting conch, mangrove buckeye, periwinkle, American crocodile

Why are mangroves important? The roots of the mangrove provide shelter for many fish and other animals. They also provide an attachment site for many creatures such as sponges and anemones. The trees themselves provide nesting site for many birds.

Why are mangroves important? Feeding grounds Mangroves are a vital source of food to many animals.

Endangered Species Florida mangroves support a number of endangered species such as: The manatee The brown pelican The eastern indigo snake The hawksbill turtle

Why are mangroves important? Act as a buffer against the high winds and eroding waves of storms. The mangroves trap sediments and prevent them from building up further out to sea, which is damaging to other ecosystems like coral reefs and sea grasses.

Why are mangroves important? Mangroves can filter out pollutants present in run-off such as: nitrates, phosphates and petroleum based The microbes in the sediment break the pollutants down.

Threats to the Mangroves: Human Settlement Mangrove communities have been significantly reduced as coastal areas have become more developed. This is especially true in Florida. The picture shows development encroaching on an area of mangroves.

Threats to the Mangroves: Human Settlement Dredging can cause flooding of the mangroves. This submerges their air breathing roots and they can not get enough oxygen and nutrients.

Threats to the Mangroves: Pollution Although mangroves filter some pollutants, they can be seriously damaged by oil spills and herbicides.

Mangrove Conservation Mangroves can reestablish in 15-30 years if conditions are right. This can be achieved by planting mangrove seedlings.