Texcoco Lake is part of the Mexico Valley hydrologic basin located in the center of the Neovolcanic Axis that crosses the national territory from the Pacific coast to the Gulf of Mexico. The area has an extension of 10,000 hectares (24,691 acres). Due to the hydraulic management activities taking place in the area, it is currently formed by reservoirs and temporary ponds, mainly: Nabor Carrillo Lake, Recreativo Lake, Xalapango Lagoon, Cuatro Caminos, Charcas de Potreros, and La Cruz.
The Federal Government is responsible for the area, administered by a Texcoco Lake Manager within the National Water Commission (CONAGUA), a branch of the Secretary of Environment and Natural Resources (SEMARNAT).
The climate is temperate semi-arid, with warm summers. Minimum rainfall is 460 millimeters and maximum is 600 mm per year, beginning in May and ending in October; the maximum temperature is 32° C between April and June, and from October to March the minimum temperature is close to 0° C.
The area receives annually an average of 150,000 migratory birds that travel through the Central Migratory Flyway. To date, 150 bird species have been identified, among them 30 are shorebirds. The area is a key breeding, wintering, feeding, and resting ground for several species of shorebirds. Regarding migratory species, the area holds record counts of up to 40,000 individuals per year of Wilsons´s Phalarope, Phalaropus tricolor. Among the representative resident species are American Avocet, Recurvirostra Americana; Black-necked Stilt, Himantopus mexicanus; Killdeer, Charadrius vociferous, and Spotted Sandpiper, Actitis macularius. Snowy Plover, Charadrius alexandrinus, is not a resident species but it uses the place as a nesting area.
During the 17th century, the Texcoco Lake was the most important water body in the Mexico Valley watershed; however it drained until its bed was exposed and consequently degraded to a point of desertification. Since 1971, an environmental improvement program resulted in the ecosystem restoration. This work and the scenic beauty of the place have attracted the attention of different sectors of society, which has been strengthened by an environmental education program directed to the general public.
As part of this program, CONAGUA celebrates the Texcoco Lake’s Wild Fauna Day, which takes place the first Saturday of December since 1999. During the event, migratory bird watching visits through the reservoirs, environmental education and outreach activities are carried out.
Despite its current condition, ecological and social characteristics, and proximity to Mexico City, the wetlands of Texcoco Lake still are a key area for shorebirds and a representative number of other resident and migratory waterbirds.
There are two main types of vegetation in the area: aquatic/sub-aquatic, and halophyte. The latter one is the most widely distributed in the area, and the pioneer species on the emerged lands of Texcoco Lake. This species is well adapted to the predominant conditions, showing tolerance to high soil salinity and frequent floods.
Through the restoration work carried out in 10,000 hectares (24,691 acres), several environments have been created, including 6,000 hectares (14,815 acres) of halophyte grasslands prairies of Egagrostis obtusiflora and Distichlis spicata, forested areas with Tamarix spp., and Casuarina spp., shallow ponds and bulrush areas; the other 4,000 hectares (9,876 acres) comprise artificial reservoirs that regulate wastewater, treated water, and rain waters. Aquatic and sub-aquatic vegetation is represented by bulrush species, Scirpus lacustris, S. californicus, S. paludosus, and Typha angustiflora.
Most of the shorebirds use the artificial reservoirs and temporary ponds as resting and feeding grounds. So far, 30 shorebird species have been recorded. The species that breed in the area are: Himantopus mexicanus, Recurvirostra americana, Charadrius vociferus, Actitis macularius, which use the shallow ponds. The H. mexicanus population nest on the grassland next to the ponds; R. americana prefers areas with scarce vegetation, and C. vociferus uses sandy and pebble beaches. Charadrius alexandrinus nests on dry soils where the difference in salt colors creates mimetic effects. Phalaropus tricolor is the most representative migratory bird species with annual numbers up to 40,000 individuals.
Flora and Fauna
It is important to mention that with the environment restoration work there has been a gradual recovery of wildlife species. Among the invertebrates, there are some hemiptera, which traditionally have been used to feed poultry. Among the fish, there is Gyrardinichtis viviparous, a species of ecological importance because it was part of the fauna of the former Mexico Valley lagoon complex. Amphibians are represented by salamanders of the genus Ambystoma spp., and three frog species: Hyla eximia, Rana pipiens, and Rana holecina. Among the reptiles of the area are: Pituophis deppei that inhabits the grasslands, lizards of the genus Scalaris spp., and a water snake of the genus Thamnophis spp. Mammal community is made up of small- and medium-sized species, who live primarily in the grasslands. Rodents are abundant: Microtus mexicanus, Peromyscus maniculatus, and Reithrodontomys megalotis, shrews of the genus Crhyptotis spp., Tuzas of the genus Papogeomys spp. There are also long-tailed weasels Mustela frenata, ground squirrels Spermophilus mexicanus, rabbits Sylvilagus floridanus, and hares Lepus californicus.
Disturbances, Impacts, and Threats
Illegal hunting, wild dogs, and conversion in land use are among the main impacts and disturbances to shorebirds in the area. Encroachment, due to the surrounding population growth, is a constant threat to the site (past, present, and future). Therefore, CONAGUA Hydraulic Security keeps a 24-hour monitoring service in Texcoco Lake area.
Priority management measures for the site include a permanent hydraulic program, maintenance of restored areas, and wastewater treatment, as well as a monitoring program for the birds’ nesting zones.
There is also an environmental management program aimed at restoring the vegetation cover through the improvement of saline and sodium soils. Hydrological resource management sustains the wetland system through the construction of hydraulic infrastructure, river channeling to regulate pluvial run-offs, as well as wastewater discharge, and the operation of wastewater treatment plants to ensure enough water for the area.
A monthly monitoring program of both resident and migratory shorebirds and waterbirds is carried out by the Texcoco Lake Manager’s Office. Monitoring data have been used as indicators to assess the environmental condition and habitat restoration during the last years. The monitoring shows records of species that were not present few years ago.
Additionally, the Environmental Education and Outreach program raise awareness about the area among different sectors of society through several activities such as field trips, bird watching, research support, and outreach material distribution that provides information about the site. Outreach materials like the "Texcoco Lake" poster have been produced with the support of CONAGUA and DUMAC. The poster focuses on shorebirds diversity in the area and the importance of their conservation.
The return of wildlife to the area is a measure of the success of the ecological restoration process. Thanks to integral management work it has been possible to establish diverse environments such as grassland prairies, forests, and wetland areas (shallow ponds, deep water bodies, and bulrush areas), which have attracted a diversity of fauna, mainly birds.
References and Documents
There are several references and documents about the research carried out in the Texcoco Lake area, including general migratory bird information and some specific information about shorebirds, which are listed below:
Alcántara, J. L., L. A. Gonzalez Olvera, B. E. Hernández Baños y E. Díaz Islas. 2001. El AICA Lago de Texcoco y su avifauna.
Chávez, C. M. T., E. Galicia-Zamora y A. Vega-López. 1991. Biología y uso del hábitat de reproducción en Himantopus mexicanus (Aves: Recurvirostridae) en Ex-Lago de Texcoco. Mem. XI Congr. Nac. de Zool. UADY.Mérida, Yuc.
Chávez, M. T., L. A. Huerta y E. Valles. 1986. Evaluación ecológica del estado actual de la comunidad de aves acuáticas del ex-lago de Texcoco. Departamento de manejo de Recursos Bióticos. Comisión del lago de Texcoco. SAR.H. México. 10 pp.
Gerencia del Lago de Texcoco. 1996. Estimaciones poblacionales de aves en el Lago Nabor Carrillo. Reporte Interno. Comisión Nacional del Agua. 5 pp.
González-Olvera, L A. 1995. Algunos aspectos sobre la biología y ecología de la reproducción del pato mexicano (Anas plalyrhynchos diazi) en el ex Lago de Texcoco. Tesis de Licenciatura. Fac. Ciencias. UNAM.97 pp.
Huerta, LA., M. T. Chávez y J. M. Chávez. 1986. Plan de manejo y desarrollo para la conservación y uso público de la comunidad de aves acuáticas del ex Lago de Texcoco. Comisión del Lago de Texcoco. SARH. México, D. F. 22 pp.
Loa, E., A. Estrada y E. Carrera. 2006. Propuesta: Programa de Conservación y Manejo para las Aves Playeras en el Lago de Texcoco, Estado de México. DUMAC. México.
Valles Rosales Evaristo. 1986. Estudio de Algunos Aspectos de la Ecología de las Aves de Ribera en el Ex Lago de Texcoco. Tesis de Licenciatura. Facultad de Ciencias. UNAM.
Valles, E. 1986. Estudio de algunos aspectos de la ecología de las aves de ribera en el ex Lago de Texcoco. Tesis de Licenciatura. Fac. Ciencias. U.N.A.M. 96 pp.
Valles, R. E., A. Huerta y M. T. Chávez. 1981 La composición actual de la avifauna del Ex-lago de Texcoco, Mex. Comisión del lago de Texcoco. SAR.H. México. 22 pp.
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The Texcoco Lake is an Important Bird Area (IBA No. 1), as well as a potentially Important Wetland for shorebird distribution within the National Shorebird Program of Mexico; and it is also contemplated in the CONABIO Priority Hydrological Region No.68.
The area comprises resting, feeding, and breeding grounds for several shorebirds. Nabor Carrillo Lake has been recognized as one of most important sites within the Phalaropus triciolor range, which is also the most abundant species in the area.
Since 1999, the “Texcoco Lake’s Wild Fauna Day” is carried out on the first Saturday of December, as part of the outreach activities that take place in the Texcoco Lake. During the event diverse stakeholders, including representatives from the government, institutions, educational centers, NGOs, and social organizations, participate in several activities promoting conservation of the area and other wetlands. Additionally, management activities implemented by the Texcoco Lake Manager’s Office are reported to the audience, highlighting the fact that they have favored the habitat restoration for the various bird species that are currently observed in the area.
Also, the Texcoco Lake Manager’s Office continuously offers guided tours mainly aimed at students (from primary, secondary, middle, and superior education). This activity fosters the knowledge on the area and the importance of integrated water management.
Cooperation agreements, developed and maintained by CONAGUA, are aimed at strengthening the hydro-ecological management and the environmental improvement of the area, which has been undertaken by CONAGUA for several years. These will allow for the continued support of joint activities, such as with DUMAC (www.dumac.org). Pond management is one of the aspects to strengthen, given the larger number of both resident and migratory species using them.
The referred actions, considering the proximity of the Texcoco Lake to the largest city in the world, will allow raising public awareness in the medium and long term about the importance of conserving this area for the benefit of the environment in the Mexico Valley.
José Heber Marquez
Technical Secretary for Lago Texcoco Management Entity
National Water Commission (CNA)
Ducks Unlimited de Mexico, A.C. (DUMAC)
Hydraulics Specialist, Lago de Texcoco Management Entity
National Water Commission (CNA)
Coordinator, Central Region
Ducks Unlimited of Mexico, A.C. (DUMAC)