Monarch Butterfly Biosphere Reserve - Ecosystem

Ecosystem

The wintering areas of the butterfly are located on the mountainous forests that stretch across far eastern Michoacán state and far western Mexico State, about 100 km northwest of Mexico City. The area on the Michoacán side consists of the highest elevations of the state, including peaks that reach 2,700 masl. The climate of the region is classed as C(w2)(w)(b’(i"); or temperate and somewhat moist with a rainy season in the summer. Average maximum temperature is 22°C (71°F), with variance between 5 and 7°C. Altitude divides the region into three sub climates (cool and semi moist, semi cold and semi moist and cold and semi moist).

The area is part of the Trans-Mexican Volcanic Belt and much of its terrain is due to outcroppings of basalt that formed fissures, faults and cliffs with a northeast-southwest orientation. These rock formations cover older ones such as volcanic cones and old lava beds. This area is highly permeable, so there is little surface water except for small ponds and arroyos. These mountains are mostly covered in forests which vary by altitude and region: holm oak up to 2900masl, holm oak and pine between 1500 and 3000 masl and oyamel fir between 2400 and 3600masl. There are also small areas with junipers, cedars and meadows. Areas below 2400 have mostly been drastically modified due to agriculture and human settlements. The most important areas to the monarch are the forests of pine and oyamel fir trees as these areas provide microclimates that provide shelter when overall temperatures fall to freezing or when there are winter rains.

The wildlife in the area ranges from the sub-tropical to the sub-arctic including a number of species that are endemic only to this area. These include white-tailed deer (Odocoileus virginianus), coyotes (Canis latrans), long-tailed weasels (Mustela frenata), grey foxes (Urocyon cinereoargenteus), rabbits (Sylvilagus spp.), crows (Corvus corax), turkey buzzards (Cathartes aura), horned owls (Bubo virginianus)(A), as well as various types of hummingbirds, reptiles and amphibians.