Central Mexican Succulent Matorral - Code: Ne2I

Central Mexican Succulent Matorral is a diverse and often stunning array of thornscrub environments spread throughout the interior of Mexico. This habitat is characterized by dense spiny undergrowth broken by towering cactus, yuccas and agaves. Mostly found at an elevation of 4000-6000ft (1200-1800m) the region is cooler than most arid shrublands on the continent. Summer high temperatures rarely break 85°F (29°C) and winter lows are well above freezing (48°F or 9°C). The matorrales receive scant precipitation during the summer monsoon season (June-September) which typically totals 7-18 in (200-500mm) depending on the year. Occasionally, hurricanes on the Pacific coast can lead to exceptional rain events that result in massive flourishes of growth.
While there is no canopy layer here, several plants in the region still reach impressive heights. The most evident botanical features on the landscapes are the massive cactus. The Organo cactus (Cephalocereus columna-trajani) grows in dense stands of unbranched columnar cactus reaching 25-30ft (8-10m) and blanketing hillsides with an unnervingly simplistic coat of giant green toothpicks.  Many branched species like Candelabro (Pachycereus weberi), Royen's Tree Cactus (Pilosocereus royenii), and Bilberry Cactus (Myrtillocactus geometrizans) can also reach considerable heights (up to 38ft/12m). Mature individuals can be as wide as they are tall, with dozens of widely branching arms. The yuccas in this environment are equally impressive. The unbranched Tree Yucca (Yucca filifera) and the many-armed Izote (Yucca periculosa) both reach upwards of 33ft (10m) and contribute the bizarre nature of this landscape. Perhaps the most impressive member of the otherworldly flora here is the Mexican Pony-tail Palm or Sotolín (Beaucarnea gracilis). With a massive bulbous trunk and spindly arms topped in pom-pom like clusters of leaves, the Sotolín can live for over 500 years and is truly one of the most whimsical and breath-taking plants on the continent.
The principal shrub layer is dense and spiny, usually reach 1.5-3m (5-10ft) in height. This brush is extremely difficult to move through and can be reminiscent of Tamaulipan Mezquital, though generally shorter and drier. Dominant shrub layer plants include Smooth Mesquite (Prosopis laevigata), Camachile (Pithecellobium dulce), Boat-spine Acacia (Vachellia campeachiana), Huisache (Vachellia farnesiana), Tarbush (Flourensia cernua), and Creosote (Larrea tridentata). There is typically very little grassy or herbaceous undergrowth except following monsoon rain events when an impressive blooms of salvia (Salvia spp.) and other bright flowering plants emerge. Large shrubs often serve as nurse plants – well established plants that help small seedlings survive early in their development. Checking the bases of nurse plants will often reveal a plethora of small, cryptic cactus species.
Individual patches of Central Mexican Succulent Matorral are separated from each other by complex mountain ranges cloaked in Madrean Pine-Oak Woodland. The extreme isolation has led to high levels of endemism, especially among cactus, yuccas, agaves, bromeliads (Hechtia spp.) and salvias. This habitat is considered a global center for biodiversity among these groups. The matorral of the Tehuacan valley alone is home more than 2700 species of plants – 30% of which are endemic!