How Climate Change is Impacting Mexico's Avian Biodiversity

The growing urban sprawl of the Mexican megalopolis shows patterns of disorderly expansion, which produces air pollution and the "heat island" effect, in addition to an excess of housing and automobiles that modify the landscape and relate multiple processes with negative effects on biodiversity.

Its inhabitants consume two to three times more resources than in other areas of the country, and most of them are often perceived as the antithesis of nature, said Leopoldo Vázquez Reyes, professor at the Faculty of Higher Studies (FES) Iztacala of UNAM.

The expert recalled that this region is one of the largest and most complex urban centers in the world, made up of Mexico City and the states of Mexico, Hidalgo, Morelos, Puebla, and Tlaxcala. It is inhabited by more than 35 million people.

The conservation land of the country's capital has an extensive area of forests, scrubland, wetlands, and agricultural areas that makeup almost 60 percent of its land area. However, more than 3,000 hectares are occupied by irregular human settlements, he warned.

This zone includes the municipalities of Álvaro Obregón, Magdalena Contreras, Milpa Alta, Tláhuac, Tlalpan, and Xochimilco. In addition, the Reserva Ecológica del Pedregal de San Ángel -located in Coyoacán, within Ciudad Universitaria- is a focal point for maintaining ecological connectivity, said the expert.

During the conference "The other face of the Mexican megalopolis: biodiversity and natural capital", given in the Carlos Graef auditorium of the Amoxcalli complex of the Faculty of Sciences of the UNAM, Vázquez Reyes pointed out that the inhabitants of the Mexican capital share the habitat of the megalopolis with thousands of species of flora and fauna.

He emphasized that Mexico City -present in the area of the Neovolcanic Axis, where the Nearctic and Neotropical biogeographic regions converge- is still a habitat of great biodiversity.

The megalopolis is home to 129 species of amphibians (33 percent of the country, 41 percent threatened); 252 reptiles (25 percent of the nation, eight percent threatened); 190 mammals (34 percent of Mexico, seven percent threatened); and 446 birds (39 percent and three percent, respectively), he explained.

Some of the sites where this variety of animals can be found, in addition to an extensive flora, are the Ecological Reserve of Pedregal de San Angel (an extension of volcanic rock of the Xitle that protects 237 hectares of xerophytic scrub of palo loco); the Natural Resources Protection Area of Lake Texcoco (a 10,000-hectare wetland and key site for reproduction, feeding, and resting of various birds).

Also, the Chinampas of the Xochimilco Wetland (associated with a traditional pre-Hispanic method of wetland agriculture and home to the salamander); and the Zumpango Lagoon Wetland (one of the last remaining relicts of the Basin of Mexico that is home to nesting waterfowl), among others. Vázquez Reyes stressed the need to protect natural capital and value ecosystem services in the urban context.

Climate Change and Bird Biodiversity

During his lecture entitled What does functional ecology tell us about the impact of climate change on biodiversity? In a bird's eye view approach, the student Acis Israel González Rodríguez commented on some results of the undergraduate thesis in biology that he is working on in the laboratory with Vázquez Reyes.

The FES Iztacala student explained that climate change affects birds due to the rise in average temperature, which causes a warmer climate; due to modifications in precipitation patterns, which cause prolonged droughts and short, intense rains; and due to a change in the distribution of environmental conditions, which implies that the appropriate habitat for the species will not be in the same place.

In the megalopolis, there are 449 native species, representing 39 percent of Mexico's diversity. Of these, 225 have been analyzed in the laboratory of this academic entity. "The fulfillment of their life cycles is closely linked to ecosystem functioning processes, which is why birds are important for the function of ecosystems".

According to data from a computer model, climate change will cause regional alterations in ecological conditions (with more heat and aridity), modifications in the spatial distribution of bioclimatic variables (suitable habitat for birds will change its position in space), and variants in the potential distribution of birds.

In addition to the conferences, the photographic exhibition "The Mexican Megalopolis and its Biodiversity in the Face of the climate change crisis" was inaugurated in the lobby of the Amoxcalli complex. It consists of more than 60 photographs taken by eight photographers.

The exhibition is made up of images by academics from FES Iztacala, the University Coordination for Sustainability, the Institute of Atmospheric Sciences and Climate Change, as well as the Autonomous University of the State of Hidalgo, the Autonomous University of the State of Morelos and the Mexican Alliance of Photography for Conservation.