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BIODIVERSITY-MEXICO: Sierra Gorda Reserve Hit Hard by Climate Change

Diego Cevallos* - Tierramérica

SIERRA GORDA, Mexico, May 21 2007 (IPS) - In the Sierra Gorda Biosphere Reserve, Mexico’s richest in biological diversity, thousands of trees are dying from the attack of pests, against which there are few viable weapons. The ongoing lack of rainfall opened the door to the onslaught.

The roundheaded pine beetle (Deondroctonus adjunctus), European mistletoe (Viscum album) and caterpillars have virulently attacked the forests of sierra Gorda, an area of canyons and hills rising 350 to 3,100 metres above sea level in the central-eastern state of Querétaro.

Some of the 50,000 residents of the reserve, extending across 384,000 hectares and a seven-hour drive from Mexico City, believe the pests have arrived out of divine will. Others say simply that “the climate has gone mad.”

According to the authorities and experts, the attack that has been recorded over the past five years is related to changes in the rainfall pattern, linked to climate change.

The phenomenon seriously threatens the zone, protected by the Mexican government, which in 1997 declared it a biosphere reserve, and by UNESCO (United Nations Educational, Scientific and Cultural Organisation), which proclaimed it a World Biosphere Reserve in 2001.

Peasant farmer Esther Martínez, from Epazotes Grandes, one of the 600 communities on the reserve, most with fewer than 500 inhabitants, sees the problem with the wisdom of someone who has always lived in the countryside.

“The forests are weak, and that is why the beetles are stronger. This is because the rains were less and now everything is drier,” says Martínez as she digs a ditch along a community field on a sharp incline to prevent rains from flushing out the soil’s nutrients.

Meanwhile, Patricia Balderas, of the town of Tilazo, believes the trees are dying because it’s “God’s intention.”

There are no exact figures available about how many oaks (Quercus), junipers (Juniperus) and pines that cover 35 percent of the forested areas are compromised. But even a visitor can see the swaths of yellow amid the green in the forest from the serpentine roads leading into the reserve.

“There is a vast infestation; it is a growing problem. It’s already part of the landscape and we can’t control it,” laments Víctor Ildefonso, assistant director of the reserve.

In the past, the plagues emerged during droughts, but disappeared when winter arrived. “Now we have them all year round and everywhere. That’s where we see the relationship with climate change,” Ildefonso told Tierramérica.

The meteorological records indicate that droughts and heat have gradually increased, and there is less and less rainfall each year, said Enrique Urribarren, then the Querétaro delegate of Mexico’s Environment Ministry, in April.

Climate change is a palpable reality in Querétaro, and over the next 13 years studies suggest that precipitation in Mexico’s central zone will be reduced five to 10 percent, Urribarren said in statements to El Universal newspaper.

“These plagues are clearly an effect of climate change. Even the people who live here say so: with less rain the forests have been debilitated,” reserve director Martha Ruiz told Tierramérica. “We don’t know what to do,” she admits.

These kinds of problems – when climate change affects flora and fauna – are the central theme of World Biodiversity Day, May 22.

Meanwhile, the only alternatives for Sierra Gorda are to cut down the affected trees, burn them, or apply pesticides. The first option is impractical because of the great number of trees – some 400 per hectare – and the other two were ruled out because of their contaminating consequences.

To seek solutions, the authorities of the Sierra Gorda Biosphere Reserve will hold an international meeting of experts at its headquarters in the city of Jalpan de Serra, population 25,000. Representatives of the U.S. Forest Service will be among the main participants.

But for now, the beetle continues to advance. It digs small chambers that reach the sap circulation of the trees, particularly pines. This cuts off the flow of nutrients, leading the tree to dry out and eventually die.

Mistletoe, another enemy, is a parasitic plant that covers the trees, especially oaks and junipers, ultimately killing them.

The caterpillars, however, consume the seeds of the stone pine (Pinus pinea, L.), affecting the tree population. The 5,000 hectares of this species on the reserve are affected.

Not only will the trees be destroyed, there will be direct consequences for the rich fauna of Sierra Gorda, due to the loss of part of its habitat and the loss of the soil’s ability to hold water.

On the reserve, where 30 percent of the land is communal property and the rest belongs to private owners, there are 360 species of birds, 130 types of mammals, 71 reptile and 23 amphibian species, and dozens of others yet to be studied. The wealth of the plant and animal life there is such that, for example, there are more butterfly species in Sierra Gorda than in the United States and Canada combined.

This is why it is described as Mexico’s most biodiverse reserve. In the Sierra Gorda converge the vegetation of the semi-desert, the cloud forest, temperate forest, and low altitude jungles, over topography with deep canyons.

Until the 1980s, livestock, farming and logging activities went unchecked in the area – a situation that began to change when, in 1989, local residents set up the non-governmental Sierra Gorda Ecological Group.

The group, whose founders included the reserve’s current director Ruiz, disseminated programmes for environmental education, reforestation, protection and regeneration of vegetation, community improvement and better solid waste management.

Those efforts were crowned with the declaration of the biosphere reserve and the arrival of international support, such as from the Global Environment Facility, which, through the UN Development Programme, has provided 6.5 million dollars since 2001.

Thanks to the combined efforts of the Mexican government, non-governmental groups and international agencies, plant and animal life in the Sierra Gorda began to recover.

But the latest attacks by the various kinds of pests could reverse what has been achieved.

(*Originally published by Latin American newspapers that are part of the Tierramérica network. Tierramérica is a specialised news service produced by IPS with the backing of the United Nations Development Programme and the United Nations Environment Programme.)