Principal ecosystems in Mexico

Principal ecosystems in Mexico

Tropical evergreen forest (rainforest)

One of the most complex and richest ecosystems on the Earth. It has been estimated that more than 50% of all animal and plant species live here.
Occurs in lowland areas (below 1200m) of abundant precipitation and year round warmth with mean monthly temperatures higher than 18 degrees Celsius (usually in between 20 and 28 degrees Celsius). The yearly precipitation is usually higher than 250 cm (150 - 400cm) and can be slightly unevenly distributed. More than 75% of species maintain their leaves all year round.

This ecosystem shows distinctive vertical stratification:

A layer - the emergents:
Widely spaced trees 30 to 40m tall and with umbrella-shaped canopies extend above the general canopy of the forest. Since they must contend with drying winds, they tend to have small leaves and some species are deciduous during the brief dry season.

B layer:
a closed canopy of   around 25m tall trees. Light is readily available at the top of this layer, but greatly reduced below it.

C layer:
a closed canopy of 20m tall trees. There is little air movement in this zone and consequently humidity is constantly high.

Shrub/sapling layer:
Less than 3 percent of the light intercepted at the top of the forest canopy passes to this layer. Arrested growth is characteristic of young trees capable of a rapid surge of growth when a gap in canopy above them opens.

Ground layer:
sparse plant growth. Less than 1 percent of the light that strikes the top of the forest penetrates to the forest floor. In such darkness few green plants grow. Moisture is also reduced by the canopy above: one third of the precipitation is intercepted before it reaches the ground.

Tropical deciduous and semideciduous forest

These ecosystems are composed of a mixture of deciduous trees and tropical evergreens and are found below 1200m above sea level. The climate has distinct wet and dry seasons. It is warm all year round. The length of the dry season varies according to the location. From 50 to 100% of the trees lose their leaves (are deciduous) during this time of periodic drought, as a mechanism to reduce water loss.
The trees here are typically not as close together as in the tropical rainforests, so more light can reach the forest floor, especially when the deciduous species have dropped their leaves.
Among the most common plants are species of genus Burseras. Other common species are Amphipterygium adstringens, Bucida macrostachya, Capparis incana, Ceiba aesculifolia, Cyrtocarpa procera, Celtis iguanea, Cephalocereus hoppenstedtii, Pachycereus weberi, Neobuxbaumia tetetzo, Agave potatorum y Agave marmorata.


Natural forest with > 30% canopy cover, below 1200m altitude, in which the vegetation is composed of thorny shrubs, bushy trees, a few sparsely scattered tall trees, and little or no grass, succulent phanerophytes with thorns may be frequent. The dry season usually extends for 6 -7 months. The annual precipitation averages 50 to 70 cm.
The most common tree species are  Amphipterygium adstringens, Mimosa eurycarpa, Cercidium praecox, Prosopis juliflora ect.


Occurs usually in regions with slightly undulating topography. The predominant vegetation is low, between 60 and 90 cm. The dry season is pronounced and long, from 6 -9 months. The annual mean temperature can range from 12 to 20C and mean annual precipitation from 30 -60 cm. The predominant species belong to genus Bouteloa,  Acacia, Agave, Quercus, Zinnia, etc. 

Xeric shrubland

Ecosystem  with thorny and deciduous elements, composed mainly of  small -leaf  bushes and characteristic for its tower -like cacti. The daily temperatures can be very extreme, reaching 42C and the diurnal changes are typically very big (frequently 20C).The mean annual temperature ranges from 12 to 26C. Xeric shrublands occur in wide range of altitudes, from the sea level to 2200 metres.
The mean annual precipitation is generally lower than 70 cm.
In areas covered with tower -like cactus species these following species can be found: Cephalocereus chrysacanthus, Pachycereus weberi, Myrtillocactus geometrizans, Escontria chiotilla, Neobuxbaumia macrocephala, Stenocereus pruinosus, Pachycereus hollianus.
The typical bush species are Acacia acatlensis, Ceiba parvifolia, Mimosa lacerata, Brahea dulcis.

Coniferous forest

As the name suggest, vegetation is composed predominantly of coniferous trees. The temperatures usually fall bellow freezing point during winter and can be considerably high in summer. Coniferous forests occur mostly on the northern hemisphere, where they form the largest biome on the Earth.
Pine forests in Mexico grow at elevations of 2,275-2,600 m and are composed mainly of Pinus montezumae (Trans Volcanic Belt area), although in more humid areas, P. pseudostrobus is the dominant species. In drier areas with more shallow soils, P. rudis and P. teocote are the dominant elements. At low elevations (below 2,000 m) P. oocarpa and P. michoacana are more common and are sometimes interspersed with P. herrerae, P. pringlei and P. leiophylla, along with some individuals of Quercus. Above 3,000 m throughout the Trans-Volcanic belt, the forests are a strict combination of Pinus hartwegii and Abies religiosa. The herbaceous stratum is well developed and epiphytes are abundant.

Cloud forest

Can be found in humid areas above 1000 m above see level. Trees usually reach more than 20m. The mean annual temperature varies from 12 to 23C, the annual mean precipitation is always higher than 100 cm and sometimes exceeds 300 cm. In many cases the forests are enshrouded in semipermanent mist giving rise to the term cloud forest.
Cloud forests harbor many species that can be found in the rain forests, but are typically rich in epiphytes, parasitic plants, bromeliads, vines, ect. The most common species are Oreomunnea mexicana, Ulmus mexicanus, Weinmannia pinnata, Liquidambar styraciflua, Chiranthodendron pentadactylon, Nyssa sylvatica, Quercus sororia, Pinus ayacahuite, Hedyosmum mexicanum, ect.

The Ramsar Convention identifies wetlands as "areas of marsh, fen, peatland or water, whether natural or artificial, permanent or temporary, with water that is static or flowing, fresh, brackish or salt, including areas of marine water the depth of which at low tide does not exceed six metres and may incorporate riparian and coastal zones adjacent to the wetlands, and islands or bodies of marine water deeper than six metres at low tide lying within the wetlands". This broad "official" definition includes a huge variety of ecosystems.

The Convention identifies 6 wetland systems:

  • marine - not influenced by river flows (e.g. coastal lagoons, rocky shores, and coral reefs)
  • estuarine - where rivers meet the sea (e.g. deltas, tidal marshes, and mangrove swamps)
  • lacustrine - areas of permanent water with little flow (e.g. wetlands associated with lakes)
  • riverine - land periodically inundated by river overflow (e.g. wetlands along rivers and streams)
  • palustrine - where there is more or less permanent water (e.g. marshes, swamps, and bogs)
  • artificial - wetlands created or radically modified by humans (e.g. fish ponds, gravel pits, salt pans)
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