Rodrigo Medellin, Mexico’s Bat Man

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Feb 192015

Rodrigo Medellin, a Mexican expert on bats (Mexico’s Bat Man) was the winner of the 2012 Whitley Fund for Nature Gold Award for his on-going work to study, raise awareness and highlight the importance of Latin America’s bats. The award reflects Medellin’s outstanding contribution to nature conservation.

This short video narrated by Sir David Attenborough, summarizes Medellin’s work:

Medellin, an ecology professor who, among many other achievements, has found bat species previously thought extinct, was the subject of an episode in the 2014-2015 season of the BBC series Natural World. The documentary won the 2014 Panda Award for Best People and Nature Film.

As a child, Mexico’s Bat Man kept vampire bats in his bathroom and some of his own blood “in the fridge so that I could feed them every night”.

Little friend: Rodrigo with one of the Lesser Long Nosed Bats his hard work has helped to conserve

Rodrigo with a lesser long nosed bats Credit: Amy Cooper, BBC2.

Bats are more important to ecology, and Mexico’s economy, than you might think. For instance, the lesser long-nosed bat is the main pollinator of the agave plants from which tequila is produced. Medellin’s research has involved tracking and understanding the extraordinary migrations undertaken by bats such as the lesser long-nosed bat, which pollinates the agaves during its annual migration. (Worldwide, bats also propagate at least 500 other economically important night-flowering species).

The bats’ journey covers 1500 kilometers (almost 1000 miles) from southern Mexico to the Sonoran Desert straddling the Mexico-USA border, via the so-called ‘Nectar Corridor’, the coastal lowlands between the Western Sierra Madre and the Pacific Ocean. Indeed, in the desert region, the lesser long-nosed bat is responsible for pollinating the distinctive saguaro cactus (which is incapable of self-fertilization), the key to the whole Sonoran ecosystem.

Elsewhere, bats can be a tourist attraction, as at Bracken Cave, Texas, home to an estimated 20 million Mexican free-tailed bats. in addition, fruit-eating bats help stimulate the regrowth of rainforests, by distributing five times more seeds per square meter than birds.

Medellin has devoted his life to ensuring the conservation of bats in Mexico and, fortunately for all tequila lovers, appears to have been successful. Because of his work, the Tequila Bat is now off the endangered species list. Over the past three decades, Medellin has campaigned tirelessly for people to appreciate the value and beauty of bats, creating a network of bat-friendly ‘safe caves’, and pioneering conservation techniques that are now being copied around the world.

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Feb 132012

No one doubts the need for reforestation in Mexico. Since colonial times, huge swatches of the country have been denuded of their native vegetation. Recent figures from INEGI suggest that Mexico has lost almost 50% of its native forests due to logging and clearance for farming and settlement. The majority of this loss is in the Volcanic Axis belt that stretches west-east across the center of Mexico at an average height of 3000 m above sea level, but tropical rainforest areas much further south have also been decimated.

There is, however, some encouraging news.

Data released by the UN Environment Programme (UNEP) puts Mexico in a lofty 4th place worldwide for the number of trees planted since UNEP began its “Billion Trees Campaign”  in 2007. According to the UNEP figures, only China, India and Ethiopia have planted more trees than Mexico.

The “Billion Trees Campaign, inspired by the work of the late Nobel Peace Prize Laureate Wangari Maathai, recognizes that trees bring multiple benefits to people, ranging from carbon sequestration and the provision of timber to soil erosion control, enhanced aesthetic value and opportunities for recreation. UNEP claims that 12 billion trees have been planted worldwide since the program began.

The short Youtube video – Taking Root The Vision of Wangari Maathai –”tells the dramatic story of Kenyan Nobel Peace Prize Laureate Wangari Maathai whose simple act of planting trees grew into a nationwide movement to safeguard the environment, protect human rights, and defend democracy—a movement for which this charismatic woman became an iconic inspiration.” (

Poster prepared by Reforestamos México A.C.

Poster prepared by Reforestamos México A.C. (Mexican NGO) Visit for more information

But are the UNEP figures all they appear to be? Certainly, Mexico’s Environment Secretariat has organized, for many years, on-going programs of reforestation and conservation designed to stem the tide of logging that decimated Mexico’s natural forests over the past century. Official figures show that the pace of this effort has accelerated in the past few years. For example, between 2007 and 2011, Mexico’s National Forestry Commission protected, restored or reforested 21,000 square kilometers  (8100 sq. mi) across the country, an area equivalent to the state of Hidalgo. The total area reforested in those five years amounts to more than 3500 square kilometers  (1350 sq. mi).

On the other hand, critics of Mexico’s forestry policies, such as Greenpeace claim that up to 70% of all lumber sold in Mexico has been illegally harvested, and that less than 60% of trees planted in national campaigns survive their first few critical years.

Deforestation in the Monarch Butterfly Biosphere Reserve

One of the most critical areas, one where continued deforestation could be a real “game-changer”, is the Monarch Butterfly Biosphere Reserve which straddles the boundary between Michoacán and the state of Mexico. This is where millions of Monarch butterflies arrive each year from as far north as Canada to spend their winter. The butterfly itself is not endangered (there are non-migratory populations in many countries, and a year-round resident population in Mexico) but what assuredly is endangered is the “migratory phenomenon” of the Monarchs. Adequate forest cover at an altitude where winter weather is consistently within a narrow temperature band is absolutely crucial to the survival of this spectacular annual migration.

According to the National University (UNAM)’s Environmental Geography Research Center, at current rates of deforestation, the area of overwintering sites for the Monarch butterflies could be reduced by 75% in the next 18 years, leaving just 12,000 ha of suitable habitat. The protected area, established in 2000, covers 560 square kilometers (56,000 ha. or 216 sq. mi) but includes land cleared for pasture, settlement and cultivation. Researcher José López García claims the reserve is losing 3% of its forest each year. He blames clearance and changes of land use more than illegal logging. The rate of forest clearance has been exacerbated by a rapid rise in the population of the El Rosario ejido. El Rosario is the gateway to the most-visited part of the reserve, attracting thousands of tourists annually. The ejido’s population rose by an average of 5.65%/year between 2005 and 2010.

How will climate change affect Mexico’s forests?

Climate change is predicted to have several effects on Mexico’s forests. These include:

  • tropical rainforests (in both Mexico and Brazil) will gradually decline in extent, rainforest soils will have reduced fertility and some parts will become tropical grasslands.
  • the semi-arid areas in central and northern Mexico will become drier, and the total area of arid areas will increase

Globally, deforestation is believed to account for 17.4% of greenhouse gas emissions, so forest protection and reforestation are key strategies in efforts to mitigate the effects of further cliamte change.

Mexico’s freshwater aquifers: undervalued and overexploited

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Nov 052011

Mexico’s groundwater aquifers are a very important resource. About 64% of public water supplies come from wells sunk into aquifers. Mexico City, Monterrey and several other metropolitan areas rely heavily on aquifers. Aquifers also provide about one-third of all the water for agriculture and livestock.

The largest aquifer resource in terms of renewable water availability is in the Yucatán Peninsula, with about a third of the national total. A large portion of the rainfall in the Yucatán seeps into its aquifers; there are virtually no rivers to carry rainwater to the ocean. The states of Chiapas and Tabasco, where rainfall is the heaviest, account for about a quarter of Mexico’s aquifer resource. The next largest sources are the Balsas and Lerma–Santiago basins but each holds less than a tenth of the national total.

Map of overexploited aquifers and areas of salinization

Overexploited aquifers and areas of salinization (Fig 6-7 of Geo-Mexico; all rights reserved)

According to the National Water Commission, 104 of the country’s 653 identified aquifers are overexploited in that more water is withdrawn each year than is naturally replaced. The velocity of water movements underground can be astonishingly slow; it may take rainwater water tens or even hundreds of years to reach the aquifer it is replenishing. (For a curious case of replenishment rates, see The Enchanted Lake).

The number of overused aquifers has increased rapidly in recent decades from 32 in 1972, to 80 in 1985, and 104 in 2004. When coastal aquifers are over-exploited, seawater seeps in to replenish the aquifer, and eventually the aquifer can become too salty to be used for irrigation. Salt-water intrusion is a significant problem for 17 aquifers located in Baja California, Baja California Sur, Colima, Sonora and Veracruz (see map).

Nearly 60% of the total groundwater extracted is withdrawn from overexploited aquifers. As expected,  the over-exploited aquifers are in the heaviest populated and the most arid areas. Total water extraction exceeds recharge in Mexico City, Monterrey and other large northern metropolitan areas as well as irrigated areas of Sonora, the central northern plateau, the Lerma basin and Baja California.

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Mexico’s water resources and water-related issues are the subject of chapters 6 and 7 of Geo-Mexico: the geography and dynamics of modern Mexico. Ask your library to buy a copy of this handy reference guide to all aspects of Mexico’s geography today! Better yet, order your own copy…

Mexico’s mega-biodiversity

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Oct 122010

People from elsewhere generally think of Mexico as an arid country with lots of cacti. The general impression is that Mexico has relatively little biodiversity in comparison with equator-hugging tropical countries such as Brazil and Indonesia.

These impressions could not be farther from the truth.  While northern Mexico is indeed arid, many areas in southern Mexico receive over 2,000 mm (80 inches) of annual precipitation, almost entirely in the form of rainfall. The rainiest place in Mexico— Tenango, Oaxaca—receives 5,000 mm (16.4 feet) of rain annually.

Mexico's postage stamps regularly celebrate biodiveristy

Mexico's postage stamps regularly celebrate biodiveristy. Click to enlarge

Straddling the Tropic of Cancer, Mexico is a world leader in terms of climate and ecosystem diversity.  It is one of the only countries on earth with arid deserts, dry scrublands, temperate forests, high altitude alpine areas, subtropical forests, tropical rainforests and extensive coral reefs. The multitude of ecosystems in Mexico supports a very wide range of biodiversity.

  • Mexico’s vegetation zones. The link is to a pdf map (in color) of vegetation zones. The map (all rights reserved) is a color version of Figure 5.1 in Geo-Mexico.

Mexico’s Environmental Ministry (SEMARNAT) indicates that there are over 200,000 different species in Mexico.  This is about 10% – 12% of all the species on the planet. About half of all Mexico’s species are endemic; they exist only in Mexico. An unknown number of endemic species were forced to extinction by the intended and unintended importation of Old World species by the Spaniards.

The U.N. Environment Programme has identified 17 “megadiverse” countries.  The list includes Mexico, the USA, Australia, five South American countries, three African countries, and six Asian counties.  Actually, Mexico is among the upper third of this group along with Brazil, Colombia, China, Indonesia and DRC (Democratic Republic of the Congo). The other countries on the list are: the USA, Venezuela, Ecuador, Peru,  South Africa, Malagasy Republic, India, Malaysia, The Philippines,  Papua New Guinea, and Australia.

Chapter 4 of Geo-Mexico: the geography and dynamics of modern Mexico discusses Mexico’s diverse climates.  Chapter 5 focuses on ecosystems and biodiversity.  Chapter 30 analyzes environmental issues and trends including the impact of Old World species imported by the Spaniards, current environmental threats, and efforts to protect the environment.  Buy your copy today to have a handy reference guide to all major aspects of Mexico’s geography!

Mexico’s ecological footprint compared to that of other countries

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Feb 162010

The ecological footprint of a country  is defined as the area of land (and water) required by a population, given prevailing technology, to produce the resources it consumes and to absorb any wastes created.

Ecological footprints are measured in ‘global hectares’ (gha). A global hectare encompasses the average annual productivity of all biologically productive land and ocean areas in the world. In 2005 the world’s population required the resources of 2.7 gha /person.  Unfortunately, the world’s biocapacity—the amount of resources its ecosystems can supply each year—was only equivalent to 2.1 gha per person and is declining each year as population increases (see graph).

The deficit between biocapacity and our ecological footprint causes damaging environmental changes to forests, fisheries, rivers, coral reefs, soil, water and air, and plays a major role in global climate change. The figures mean that our current usage of the world’s resources is inherently unsustainable.

Click here for a printable bookmark of this graph (pdf file)

The graph shows the ecological footprint of several countries. China’s footprint matches global biocapacity while the footprints of India, Indonesia and Bangladesh are fully sustainable. On the other hand, the USA’s footprint of 9.4 gha is surpassed only by the United Arab Emirates. Australia and Canada both have footprints over 7 gha. In simple terms, their populations require more than three times their fair share of the world’s biocapacity.

Chapter 30 of Geo-Mexico: the geography and dynamics of modern Mexico, from which this extract is taken, looks in much more detail at the implications of ecological footprints and at alternative ways of assessing ‘sustainability’.

Lake Chapala lake levels

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Dec 282009

Updated figures for Lake Chapala (Figure 7.1 in Geo-Mexico):

2008 – maximum level: 96.54

2009 – minimum level: 95.44; maximum level: 95.83 (7 October 2009)

The figures show that the lake is still well below its “historic norm” level.