Distribution of Thelocactus species in the Mexican ecoregions. Click on the coloured areas of the map for a short description.
More information can be found here: WWF - Deserts and xeric shrublands
and here: The Encyclopedia of Earth - Ecoregions of Mexico.
GIS source for the ecoregion map: World Wildlife Fund.
Ecoregions
Biodiversity is not spread evenly across the Earth but follows complex patterns determined by climate, geology and the evolutionary history of the planet. These patterns are called "ecoregions".
WWF defines an ecoregion as a "large unit of land or water containing a geographically distinct assemblage of species, natural communities, and environmental conditions".
The boundaries of an ecoregion are not fixed and sharp, but rather encompass an area within which important ecological and evolutionary processes most strongly interact.
Veracruz moist forests
This moist forest ecoregion is situated on the Gulf of Mexico's northeastern coastal plain of Mexico, in the north of Veracruz and the south of Tamaulipas states. The ecoregion encompasses lowlands of the eastern slopes of the Sierra Madre Oriental. The climate is tropical humid, with rains during seven months of the year with mild temperature oscillations. The precipitation levels range between 1100 and 1600 mm each year.
The moist forests of Veracruz ecoregion constitute the northernmost portions of moist forest and associated subhumid tropical vegetation distributed in Mexico. Veracruz has been described as one of the richest faunistic regions in the west hemisphere, and is one of three regions with the highest insect richness and endemism.
Source: The Encyclopedia of Earth.
Tamaulipan matorral
The region is formed by the lower elevations of the Sierra Madre Oriental that gradually diffuse into the northeastern coastal province of Tamaulipas. One part of the region is composed of abrupt mountains, but low valleys and vast plateaus mostly dominate it. Sever frosts limit the species capable of living in this ecoregion. Xeric conditions also contribute to species limitations as the small quantities of rain that does fall is quickly soaked up by the limestone base. Desert like conditions are perfect for succulents such as cacti, which exist in such numbers in this ecoregion that it is designated a priority area for their protection.
Source: The Encyclopedia of Earth.
Tamaulipan mezquital
The Tamaulipan/Mezquital ecoregion of southern Texas and northeastern Mexico has unique plant and animal communities containing tree and brush covered dunes, wind tidal flats, and dense native brushland.The ecoregion is located on the physiographical province known as the Coastal Gulf Plain. It begins in the eastern part of the Coahuila State, in Mexico at the base of the Sierra Madre Oriental, and then proceeds eastward to encompass the northern half of the state of Tamaulipas, and into the United States threw the south western side of Texas. Elevation increases northwesterly from sea level near the Gulf Coast to a base of about 300 m near the northern boundary of the ecoregion, from which a few hills or mountains protrude.
The Tamaulipan/Mezquital constitutes a unique assemblage of mesquite grassland in northeastern Mexico and the southern United States. The ecoregion contains at least four endemic genera of woody plants, and it is also a rich zone in terms of endemic cacti, as well as the occurrence of endangered species.
Source: The Encyclopedia of Earth.
Sierra Oriental pine-oak forests
This ecoregion is found in the Sierra Madre Oriental mountain range of eastern Mexico and southern Texas, and is dominated by pine-oak forests growing at altitudes between 1000 and 3500 m above sea level. The mountains run north to south along the eastern half of Mexico, including the states of Coahuila, Tamaulipas, Nuevo León, San Luis Potosí, Querétaro and Guanajuato, and less significantly just over the Rio Grande in several isolated mountain massifs in southern Texas.
The Sierra Madre Oriental pine-oak forests represent an island of temperate environments surrounded by more humid and tropical ecoregions to the south, and xeric ecoregions to the north. This positioning has been a major factor contributing to the ecoregion's diversity and high numbers of endemic species. From the small islands of temperate forests in the middle of the harsh Chihuahuan Desert, to the cloud forests of Tamaulipas on the east slope of the ecoregion, endemic and endangered species thrive at high altitudes throughout the mountains. The ecoregion is a center of diversification for the genus Quercus, and is also recognized as the area of highest diversity for the genus Agave.
Source: The Encyclopedia of Earth.
Central Mexican matorral
Situated in central Mexico, this region is surrounded by the Sierra Madre Occidental Mountains to the west, by the Sierra Madre Oriental Mountains to the east, and by the rugged Trans-volcanic belt to the south. The region constitutes the southernmost portion of the Mexican central meseta, which is an extensive portion of flatlands running south from the Mexico-US border in the state of Chihuahua.
The matorral of central Mexico is characterized by its high concentration of endemic species. In the state of Hidalgo, the vegetation is composed by three different kinds of xeric scrub, which is a characteristic that contributes to increased diversity and richness of arid plant species. The diversity of cacti is important in Hidalgo, because there are nearly 17 species in a very small area.
Source: The Encyclopedia of Earth.
Meseta Central matorral
Located in central Mexico, this region is surrounded by the Sierra Madre Occidental Mountains on the west, by the Sierra Madre Oriental Mountains in the east, and by the rugged Trans-volcanic belt to the south. The region constitutes the central portion of the Mexican Meseta Central, an extensive portion of flatlands occurring in north-central Mexico. The region is dominated by desert plains, with a few hills and mountains that rise up to 2400 m above sea level. The climate is dry and hot, with precipitation levels below 500 mm per year.
The Meseta Central matorral ecoregion is one of the most extensive floristic and physiographic provinces of Mexico, and is a region where past geological events have promoted the diversification of the biota. This region was isolated from other arid regions in Mexico in the past. Orogenic activity fragmented the Meseta Central and the surrounding areas (that now constitute three of the most important mountain ranges of Mexico). The subsequent isolation of the region favored the differentiation and evolution of endemic species in each of the fragmented portions, therefore the matorral of the Meseta Central is characterized by its high content of endemic species. At least 16 endemic genera of woody plants and cacti have been described from this province (e.g. Dasylirion, Eutetras, Sartwellia, Ariocarpus, and Lophophora).
Source: World Wildlife Fund.
Chihuahuan Desert
The Chihuahuan Desert encompasses one of the most biologically diverse arid regions on Earth. The Chihuahuan Desert stretches from the southeastern corner of Arizona across southern New Mexico and west Texas to the Edwards Plateau in the United States. It runs deep into central Mexico, including parts of the states of Chihuahua, northwest Coahuila, northeast Durango and several others. This desert is bounded by the Sierra Madre Occidental to the west and the Sierra Madre Oriental to the east, extending as far south as San Luis Potosi and to disjunct islands of the Chihuahuan vegetation in the states of Queretaro and Hidalgo.
The Chihuahuan desert is one of the three most biologically rich and diverse desert ecoregions in the world, rivaled only by the Great Sandy Tanmi Desert of Australia and the Namib-Karoo of southern Africa. Approximately 3500 plant species live in this desert, and estimates of endemism state that there could be up to 1000 endemic species (29%), and at least 16 endemic plant genera.
The high degree of local endemism is the result of the isolating effects of complex basin and range physiography, and dynamic changes in climate over the last 10,000 years. Another contributing factor to endemism is the colonization of these inhospitable habitats by specialists species with restricted ranges. Taxa with a high level of local endemism include cacti, butterflies, spiders, scorpions, ants, lizards and snakes. However, this ecoregion also sustains some of the last remaining populations of Mexican prairie dogs, wild American bison and pronghorn antelope.
Source: The Encyclopedia of Earth.
