Our world, filled with a diversity of life and ecosystems is perhaps undergoing a new mass extinction, produced and conducted by exploitation and expansion. Consequently, regions of the earth have been marked into hotspots, spanning regions of vast biological diversity, but under the threat of humans. One such hotspot is the Madrean Pine-Oak Woodlands in Mexico and Southern United States.

The Madrean Pine-Oak Woodlands hotspot includes Mexico’s main mountain chains, namely the Sierra Madre Occidental, the Sierra Madre Oriental, the Trans-Mexican Volcanic Belt, the Sierra Madre del Sur, and the Sierra Norte de Oaxaca, as well as isolated mountaintop islands in Baja California (particularly around the Sierra de la Laguna). Although the vast majority of the hotspot’s 461,265 km² lie within Mexico, a few scattered patches occur in the southern United States (represented by the Madrean Sky Islands, a series of about 40 mountain-tops in southern Arizona and New Mexico). The complex geological history of the Madrean Pine-Oak Woodlands is evidenced by its rugged mountainous terrain, high relief, and deep canyons. The Trans-Mexican Volcanic Belt, which runs from west to east across central Mexico, and serves as a bridge connecting the Sierra Madre Occidental and the Sierra Madre Oriental, is the highest mountain chain in the hotspot, including the peaks of Pico de Orizaba (5,747 meters) and Popocatépetl (5,452 meters). The climate of the hotspot is primarily temperate, with annual precipitation varying between 500 and 2,500 millimeters, largely depending on slope and aspect.

The red represents the hotspot.

A quarter of all Mexico’s plant species are found here, many of them found nowhere else on Earth. The pine forests of Michoacán provide famous overwintering sites for the annual migration of millions of monarch butterflies. Unfortunately, the destruction of pine forests due to excessive logging is the leading cause of habitat loss in this region. The pine-oak woodlands are composed of stands of oak (Quercus), pine (Pinus), douglas-fir (Pseudotsuga) and fir (Abies). Pine and oak forests are the characteristic vegetation type in the hotspot, ranging from monospecific stands of either pines ( Pinus) or firs ( Abies) to almost pure stands of oak ( Quercus). In between these two extremes, different regions have varying combinations of species, with some more dominant than others. The pine-oak woodlands have an insular-type distribution by virtue of being surrounded by more extensive floristic provinces, generally tropical or arid. This feature is particularly noticeable in the northern Mexican Highlands and the Madrean Sky Island Archipelago. The World Wildlife Fund recognizes several distinct pine-oak woodlands ecoregions, based on geographic distribution and species mix.

The Sierra Madre Occidental Mountains.

The threats to the Madrean Pine-Oak Woodlands area are greatly in direct relation to human involvement. Whether that is through logging which has increasingly become a major concern for conversationalists- through the massive deforestation to gather resources of oak and other forms of timber for further distribution both globally and locally.
While forest fires are a natural ecological development throughout the Madrean Pine-Oak Woodlands, fires now are being seen to be more man made than of natural developments. This is with the goals to encourage new sprout growth throughout the forest for further logging, deforestation, vegetation collections for culinary means as well as various other forms of outsources and distribution. A main reason for intentional forest fires is also to feed the local livestock and a quick way to free-up the land for further economical and architectural development.

Hope for the Madrean Hotspot

The vast majority of the hotspot lies in Mexico’s main mountain chains with outlying mountaintops in Baja California and the Southern United States. Estimated at 461,265 km2, only some 27,000 km2 is under some form of protection, while 8,900 km2 are in protected areas in IUCN categories I to IV. The International Union for Conservation of Nature (IUCN) has categories that determine how a certain area is managed and protected.

The Madrean Pine-Oak Woodland area is somewhat protected up to about six percent; the IUCN only protects around two percent. Endemic terrestrial vertebrate species, located on the slopes of Sierra Madre Del Sur are unprotected. The Moarch butterfly Biosphere Reserve in Michoacan is an important protected area that preserves the migration of monarch butterflies.

The hotspot in Southern United States has protection operated by private owners such as The Nature Conservancy. Other private owners are designated as U.S. National Monument or U.S Wilderness Area protectors. A network of Mexican and international partners called the Sierra Madre Alliance work to preserve the biodiversity of functioning forested ecosystems via local participation. One particular company, Cemex, a cement company that has bought land within the Madrean Pine-Oak Woodlands, has taken the expansion of the protected land all the way to to the Big Bend national park in Texas. CEMEX has successfully protected the lands it has bought.




7 responses »

  1. I think it was very interesting how the post focuses on both fauna and flora and shows an inevitable connection between their extinction (forest – monarch butterfly). As stated in the note, deforestation has both short-term and long-term consequences, leading the area to a complete extinction. First, the animals and plants lose their habitat instantly. Second, most of clearing of the forests is done by fire, which destroys the soil and it is even harder to restore the environment. This is yet another example how human ignorance and drive for money goes beyond rational thinking and taking care of the environment. I think the lack of awareness among local community is alarming and should be a primary target for all NGOs and governments, working on improving the situation.

    – Kasia (Katarzyna) Dybek

  2. Personally, I find a connection with this post because I am half-mexican and have never visited the country. I hope to visit there one day and experience everything that the country stands for. Although the post is mainly about the deforestation and the extinction of plants and insects of the Madrean Pine-Oak Woodlands and the Sierra mountains, the hotspot is beautiful and amazing in its nature. Its a shame that the consequences are short-term and long-term. I would love to travel and visit one day; this post has encouraged me to visit this location eventually. 🙂

  3. Leo Costa says:

    This blog show’s the dire consequences of deforestation. The animals and plants loose their natural habitat since man destroys the soil with fire. We need to raise awareness for the locals since they face serious repercussions. It is a shame because this is one of the most beautiful hotspots in the world.

  4. Ashley Raynor says:

    I was very surprised to read that a third of Mexico’s plant species are in this one area, many of which are not found anywhere else on earth – I love to hear about species that are found only in one place on the earth…very interesting.

  5. Grace Betts says:

    I’m running out of different things to say about these articles. All of them are just reiterating how the impact of humans are severely injuring these different areas of the world. It is somewhat comforting to know that at least pieces of this diverse area are protected, but it never seems to be enough.

  6. Until reading this I was pretty much completely ignorant to the fact that Mexico was home to such vastly rich forestry in it’s mountainous regions. It’s nice to hear that atleast some of it’s vegetation are being protected from deforestation, but the amount seems almost insignificant to the amount that isn’t protect unfortunately. After having watched many of the documentaries and reading a lot of these posts it’s obvious that almost everything is caused by humans, and from the looks of it pretty much irreversible.

  7. Dave Swanson says:

    a lot of people discount the contributions mexico has to a diverse biological community on the general stereotypes we have for the nation. It is nice to see someone bringing a light to the beautiful aspects of Mexico.

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