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Morichal stream, Villavicencio, Colombia

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Colombia, Meta, Villavicencio

Morichals are small rivers, streams or lagoons surrounded by moriche palms (Mauritia flexuosa) which is a palm that only grows and thrives where its roots can be underwater. Morichals is just the name given in Spanish to a large group of moriche palms. A good example of a morichal is in the Morichal Largo river in northeastern Venezuela. But you will generally find them all over the Venezuelan and Columbian low lands, but also in the savannah areas of the Amazon river basin.

This interesting ecosystem supports a rich variety of fish fauna both in the mainstream and in the small streams leading into the main Morichal. These palms get their water by digging their roots in the water, and so they are a natural filter to the water. That’s why these waters are always crystal clear.

But you will also find black water morichals, that’s because the leaves and other botanicals of the palms fall into the water and release tannins.

Submitted by
Manoah Grootjans
Approved by
Roberto E. Reis, Pablo C. Lehmann and Flávio Lima
GPS
4.0422220, -73.6380539
Geographical region
South America
Drainage Basin
Orinoco
River catchment
Rio Meta
Water body type
Stream
Water body name
Morichal
Water body part
Channel
Water body course
Lower course
Water body: tributary of
Rio
Tributary name
Rio Meta

Water Chemistry

Water information

Water type
Fresh water
Water color
Mixed water
Water transparency
High
Concentration of sediments
No
Water temperature
22-28 °C
Water flow/curent
Slow

Chemical parameters

pH
6
Conductivity
GH
5 mg/l
KH
5 mg/l
Dissolved Oxygen

Substrate in nature

Sand
Beige
Pebble/Gravel
Grey
Stone
Grey
Stone form
Flat
Silt/Mud
None
Leaves
Few
Driftwood
Few
Submerged terrestrial vegetation
Yes

Aquatic Biotope

Date of collecting
April, 2023
Collecting area
Water depth
0,5m
Air temperature
21 °C
Sunlight
Full sun

Environment

Environment
Affected by human activity
Affected by human activity
Agriculture
Agriculture
Advanced
Surrounding area

The llanos main river is the Orinoco which has most of its tributaries going through the llanos, like the Rio meta, Rio Bita, Rio Cinaruco. But also the Rio Meta tributaries like the Rio Pauto and the Rio Guachiria.

The climate is a tropical savanna climate that grades into a tropical monsoon climate. Rainfall is highly seasonal with a rainy season from April to November and a dry season between December and March. The wettest months are typically June and July. In the rainy season the plains flood up to one meter high. Heavy rains mean the grasslands and forest transform into temporary wetlands.

The flooded llanos serve as important breeding and nursery grounds for a large number of fishes. Its main rivers serve as migrating routes for many large river species. The llanos is also home to lots of other animals and birds like: capybara, tapir, capuchin and red howler monkey, porcupine, puma, anaconda, caiman, storks, wistling ducks, hoatzins and spoonbills.

The indigenous people of the llanos include guahibo in the western llano of Venezuela and Colombia and the yarura in the eastern llanos of Venezuela.

Underwater landscape

The llanos are a vast tropical grassland that is located east from the Andes in Columbia and Venezuela. it spreads over an area of 375.787km². You will find lots of different water body’s and underwater habitats in the llanos. Like streams, rivers, lagoons, morichals, creeks and lots of swamps.

Fishes:

  • Corydoras metae (Callichthyidae)
  • Apistogramma macmasteri (Cichlidae)
Threats to ecology

Wildfires because of the high heat.ì and oil digging.

Bibliography

  • Morichal Largo by Ivan Mikolji

Comment by the expert

Roberto E. Reis: Description of the location short, and description of surroundings too wide. Description of threats restricted to wildfires. One photo of the biotope outside water. Four fish and one plant species listed. Description of the aquatic habitat, riparian zone, and underwater landscape too general. Bibliography/Sitography weak.

Flávio Lima: The participant presented a broad description of the morichal habitat. However, morichales are more typical from areas eastern to the piedmont areas where Villavicencio is located. Also, the green cardinal (Paracheirodon simulans) does not occur in the region of Villavicencio; its area of occurrence in the Orinoco basin is the more central and upper portions of the basin, near the main trunk of the Rio Orinoco, and also prefers the floodable areas with aquatic plants and not the morichales per se (better choices would have been Hyphessobrycon metae, Hyphessobrycon saizi, Hemigrammus barrigonae, or Axelrodia riesei).

Pablo C. Lehmann: In summary, the information provided about Morichals in the South American llanos offers valuable information about this unique ecosystem. However, it would have been interesting to have included other sources of consultation, perhaps a video of the natural environment and more detailed descriptions of the fish and plant species, the habitat and perhaps including more information on local threats to the natural ecosystem.