The Samaan Grove Wetland System

Wetlands Inhabitants
Floating, Submersed & Moisture Loving Plants

by Kevin Kenny - Click images to enlarge

Floating Plants

The only one of the many floating plants available to us that is being considered at Samaan Grove is water poppy (Hydrocleys nymphoides), which grows in the Nariva Swamp. It will survive in water depths of up to 40 centimetres (16 inches) deep but prefers shallow conditions with depths of 10 to 15 centimetres (4 to 6 inches). It likes rich topsoil which would indicate that it should do well on the shelf at SWW#6.

The photo at the right was taken at Nariva and shows the plant only growing at the side of the wetland. We plan to introduce this plant after the shelf has matured.

Submersed Plants

One of our main plans for all the lakes and ponds built has been to have the sides and bottoms entirely covered in submersed plants. This would help keep the lakes clear by preventing the soil from suspending in the water. The five types of plants we are experimenting with are tape or eel grass (Vallisneria americana), Sagittaria subulata, Amazon sword plant (Echinodorus amazonicus), hair grass (Eleochariss acicularis) and various types of Cryptocoryne

Vallisneria americana. The one grass that has done very well is Vallisneria. It was placed in SWW#6 which receives runoff from Lake1B. It took a good six months for the plants to establish. Once the rains arrived in June 2006, growth of this grass exploded and has almost covered the entire bottom of this pond.


^ v Vallisneria americana

One of the main problems we encountered in the early days was the appetite of the ramshorn snails that seem to feast on the young leaves. It took a few attempts and a large number of individual plantings for the grasses to grow faster than the snails' ability to consume them. Once the first plants colonized they spread around the edges of the wetland pond. What continues to limit the growth down to the very bottom is the lack of clarity of the water, limiting sun to the underwater leaves. 

Sagittaria subulata. This is one of our favourite underwater aquarium plants but has proven difficult to grow at Samaan Grove. We placed a number of young plants in three separate ponds with little early success. It is difficult to say what conditions impeded their growth.

 
Sagittaria subulata
We have since planted it in the new lake in Samaan II along with the Amazon sword plant and the results have been encouraging. Ribbon shaped leaves grow up to 24 centimetres (9.5 inches) long and may be as much as 1.5 centimetres (.6 inches) wide. The plant reproduces by runners and is already forming dense colonies on the sides of the lake which help to stabilize the soil.   

Cryptocoryne. We have also been planting Cryptocoryne in all the lakes and ponds with little success to date. These plants were received from Peter Moll who had imported them to sell to the aquarium trade. He gave us two batches, one of which was planted at Samaan Grove while the other was kept in an aquarium. Most crypts do not like a lot of light and prefer clear water. They will also grow in moist soil so it is difficult to understand why we have not had better results.

Amazon Sword Plant, Echinodorus amazonicus. So far we have had tentative success with Amazon sword plants. The submersed leaves seem to hold silt and have not grown well. We transplanted them in Lake 0 and are now starting to see better results.  

Hair grass, Eleocharis acicularis. On a visit to the Nariva Swamp in 2002, we had lunch at one of the villager's homes and were fascinated by a pond in his back yard. The pond was completely covered with hair grass seen in the photo below left. He claimed that it was filled with only rain water which was the reason it remained so clear and clean. Ten feet away there was a much larger pond and the water clarity was terrible. In our opinion it was the hair grass that produced the different result.

To commercial lake managers, the genus Eleocharis should be avoided. Most of the species are problematic weeds that clog waterways. We plan to use this grass at the very end of the wetland system just before the fresh water enters the sea. This is where it grows in Trinidad. We have never seen it growing in Tobago.


 
Eleocharis acicularis ^ >
 


Moisture Loving Plants

Heliconia. We introduced a number of Heliconias as background plants in many of the wetlands. They seem to grow well in moist soil conditions and provide excellent habitat for wildlife. We are still experimenting with different varieties.



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