GRASSLANDS IN MEXICO: CHARACTERISTICS, LOCATION, FLORA, FAUNA - ENVIRONMENT - 2024

The grasslands of Mexico are called zacatales and correspond to plant formations where the dominance of grasses is almost absolute. The name zacatal comes from zacatl in the Nahuatl language and means grass or grass.

The extension occupied by the pastures of Mexico reaches about 10 or 12% of the Mexican territory. These are low to medium grasslands that grow mainly in arid or semi-arid areas.

Pasture in Mexico. Source: Juan Carlos Fonseca Mata

In Mexico there are two basic types of natural grasslands, one of these being called zacatales in plains with low grasses. On the other hand, the zacatonales or alpine pastures above the tree line (4,000 meters above sea level), with higher pastures.

Furthermore, most of the natural grasslands have been altered for grazing livestock. As well as pastures for breeding have also been created from areas with other types of vegetation such as forests and shrubs.

The dominant flora are grasses with genera such as Bouteloua, Andropogon, Eragrostis, Aristida and others. There are also some shrubs like Ephedra compacta and izote (Yucca periculosa) as well as scattered trees, particularly of the legume family.

In the fauna we find the pronghorn, bison, lynx, plains dogs, the golden eagle and the owl called burrowing owl. Among the insects, the grasshoppers called chapulines stand out, from the Nahuatl "insect that bounces like a rubber ball."

The climate in the Mexican grasslands is semi-arid with annual rainfall of 300 to 600 mm, reaching 800 mm in the alpine grasslands. While the annual average temperatures vary from 12 to 20 ºC in the plains and from 3 to 5 ºC in the mountains.

Characteristics of Mexican grasslands

Pico de Orizaba Photograph taken by: Isaac Ramirez Chiunti

The grasslands in Mexico called zacatales are equivalent to the prairies of the North American Midwest. Similarly, the term grassland is used to refer to high mountain grass formations.

These plant formations are equivalent to the mountain meadows or alpine meadows, the puna or the páramo. In this case they are called zacatonales, alluding to the greater height of their pastures.

- Plant structure

The grasslands of Mexico or zacatales, are vegetal formations dominated by low to medium grasses, 20 to 70 cm high. The strict grassland lacks trees or shrubs, or these are scarce and widely scattered.

Zacatonal in the Nevado de Toluca (Mexico). Source: Juan Carlos Fonseca Mata

In the alpine pastures the grasses can reach up to one meter in height, which is why they are called zacatonales.

- Relief and ground

Grasslands in Mexico develop on plateaus, valley bottoms, and gently sloping slopes. They are found from 450 meters above sea level in Sonora to 1,100 or 2,500 meters in most cases.

Floors

Soils tend to be moderately deep and fertile with loam to sandy loam or clay loam textures. They are moderately rich in organic matter and with a pH between 6 and 8 and in grasslands it is mostly of volcanic origin.

- Grassland types

Among the grasslands of Mexico, two basic natural types are distinguished by the relief where they develop.

Plain grassland

The plain grassland develops in the extensive plains, as for example in the Jano Biosphere Reserve. This is characterized by including low and medium grass species.

Alpine pasture

The alpine pasture is formed in the high peaks of Mexico, above the limit of tree growth (4,000 masl). Thus, at the top of Iztaccíhuatl, Nevado de Toluca, Cerro Potosí or Tacaná Volcano, pastures tend to be higher and with less coverage.

Almost all the mountains that present this type of alpine meadow or pasture are found in the southern half of the country. The alpine pasture reaches its maximum height between 4,300 and 4,500 meters above sea level.

Cultivated grasslands

Most of the natural grasslands in Mexico have been altered to be used for raising livestock, mainly cattle. In this process, non-native grass species are introduced and the soil structure is intervened.

New grasslands have also been established in areas whose original vegetation was forest or scrub.

Location

In Mexico the grasslands extend from the north to the center of the country and on the peaks above 4,000 meters above sea level. They constitute a wedge-shaped extension to Mexico of the prairies of the North American Midwest.

The most extensive natural grassland area is developed in the highlands along the base of the Sierra Madre Occidental. The largest surface of this plant formation is found in the states of Sonora, Chihuahua, Durango, Coahuila, Zacatecas and San Luís Potosí.

Protected areas

There are 8 national parks and two biosphere reserves where important areas of wild grasslands are protected in Mexico. One is Jano, located on the border with the United States and the other is Mapimí, which is located between Durango, Coahuila and Chihuahua.

Flora

Despite Mexico belonging to the North American subcontinent, the flora of its grasslands is more closely related to that of South America at the level of genera.

- Plain grasslands

Herbs

The dominant family is Poaceae or Gramineae, with species such as navajita grass (Bouteloua gracilis), resistant to drought and with sharp leaves. The genus Bouteloua is one of the most characteristic of the Mexican grasslands, with various species.

Other common genera in grasslands in Mexico are Andropogon, Aristida, Buchloe, Eragrostis, Enneapogon, Leptochloa, Setaria, Sporobolus, and Stipa.

Shrubbery

Among the small shrubs found in the grasslands in Mexico is the canutillo (Ephedra compacta), a gymnosperm of the Ephedraceae family. There are also shrubs of the Euphorbiaceae family such as candelilla (Euphorbia antisyphilitica).

Some shrubs reach greater height, such as the izote (Yucca periculosa) of the Asparagaceae, with rosette leaves at the ends of the stems.

Trees

A characteristic tree species of some wooded grasslands is the mesquite (Prosopis laevigata), a mimosoid legume. While another arboreal legume is the ocotillo (G ochnatia hypoleuca).

Mesquite (Prosopis laevigata). Source: Sue in az

There are also grasslands with scattered arboreal elements of Acacia and even oak (Quercus emoryi). However, the most common is that the proliferation of trees in the zacatales is the product of alterations caused by humans.

- Alpine grasslands

Here are endemic species such as the mountain stag (Castilleja tolucensis) and the toad grass (Eryngium proteiflorum).

Tillering grasses such as Festuca tolucensis or Muhlenbergia and Calamagrostis species are typical of the alpine pasture. Also cushioned plants such as Arenaria bryoides.

Associations

In some areas, three types of alpine grassland associations are distinguished. In one Muhlenbergia quadridentata dominates between 3,700 and 3,800 meters above sea level. At higher altitudes between 3,800 and 4,200 meters above sea level, Calamagrostis tolucensis and Festuca tolucensis predominate.

Between 4,200 and 4,300 meters above sea level, there is a predominance of the species Festuca livida and Arenaria bryoides.

Fauna

Herbivorous animals dominate the Mexican grasslands, as in all grasslands in the world.

- Mammals

Pronghorn (

Pronghorn (Antilocapra americana). Source: Leupold, James C.

Although it is called American antelope, it is not a true antelope. It moves in herds of hundreds of even animals, feeding on grasses and mosses.

Jaguar (

Although in danger of extinction, the jaguar still inhabits areas of the Mexican prairies, such as the Jano Biosphere Reserve. This species is considered the biggest predator in this ecosystem.

Bison (

American bison (Bos bison) in the Jano Biosphere Reserve. Source: Fernando del Real

The American bison was abundant in the plains of North America, including Mexico, however hunting drastically decreased their populations. In the case of Mexico, it disappeared, but has been reintroduced into the pastures of the Jano Biosphere Reserve.

Lynx (

The bobcat or bobcat is a feline that reaches twice the size of the domestic cat. It feeds on small prey such as hares, although it can also be a scavenger.

Mexican llanero little dog (

It is a threatened species because it has been considered an agricultural pest that feeds on herbs and insects. He himself lives in groups, living in tunnels dug in the plain.

Blacktail Llanero puppy

It is a more widespread species than the previous one and is characterized by the black stripe on its tail.

Tlalcoyote (

It is the North American badger, equivalent to the European badger which is a carnivore that catches small prey such as mice, squirrels and marmots. These animals dig their burrows in the soil of the plain, so they prefer areas of soft soil.

Teporingo or volcano rabbit (

It is an endemic species of the mountains of central Mexico, found among other habitats in the alpine grasslands. This rabbit is in danger of extinction, and it is also known as zacatuche, which in Nahuatl means rabbit of the zacatonales.

- Birds

Golden Eagle (

This is one of the most widely distributed eagles in the Northern Hemisphere, including the Mexican grasslands. Their prey include prairie dogs.

Roadrunners (

It is a terrestrial bird although it makes small flights to the trees and moves quickly, taking quick turns. Feeds on small prairie reptiles, mammals, and insects.

Burrowing owl (

This little owl lives in burrows dug by prairie dogs and other animals. Unlike other owls and barn owls, this species remains active during the day.

Scaly quail (

It is a galliform bird that feeds on leaves, fruits, seeds, and insects in grasslands. It is about 30 cm tall and has a striking white crest, with a variegated white-black-blue body pattern especially on the neck and chest.

Western Prairie (

It is a songbird with a yellow color on its belly with a black V on the chest and a back mottled with black and brown. It feeds on insects, fruits and seeds in the pasture.

- Reptiles

Blood cry (

Although it is not a chameleon, it is called a mountain chameleon and it is a plump lizard 12 cm long, endemic to Mexico. It has numerous thorns and horns that make it very showy and it feeds on insects, especially ants.

Great Plain Toad

It is a brown and greenish gray toad that feeds on butterfly larvae and lives in caves dug in the grassland.

- Insects

The chapulin (

It is a green grasshopper in various shades of yellowish and red, very striking.

Weather

- Precipitation

In the plain grassland, the average annual rainfall is low and fluctuates between 300 and 600 mm, with 6 to 9 dry months. On the other hand, in the alpine pasture the average annual rainfall varies between 600 and 800 mm and a significant part falls in the form of snow.

- temperature

Plain grassland

The average annual temperature varies in most cases between 12 and 20 ºC and night frosts are frequent. Temperature variations during the day can be very extreme, from 0ºC at night to 30ºC during the day.

This daily thermal oscillation is due to the high solar radiation that affects these areas during the day

Alpine pasture

In the alpine pastures the average annual temperature varies between 3 and 5 ºC, with frosts every month. In the highest parts of Chihuahua and Sonora snowfall occurs frequently.

References

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2. Calow, P. (Ed.) (1998). The encyclopedia of ecology and environmental management.
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5. Purves, WK, Sadava, D., Orians, GH and Heller, HC (2001). Life. The science of biology.
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8. World Wildlife (Viewed on 5 August 2019). worldwildlife.org/biomes/montane-grasslands-and shrublands
9. World Wildlife (Viewed Nov. 9, 2019). worldwildlife.org/biomes/temperate-grasslands-savannas-and-shrublands
10. World Wildlife (Viewed Nov. 9, 2019). worldwildlife.org/biomes/tropical-and-subtropical- grasslands-savannas-and-shrublands