Historical records of this species indicate presence in six municipalities near Toluca between 2,500-3,000 m asl. Currently, it is restricted to the central highlands of the State of Mexico, near the city of Toluca, in the Río Lerma and the Lerma Lake around Almoloya (Area de Protección de Flora y Fauna Ciénagas de Lerma). It has an extent of occurrence of 303 km2 and an area of occupancy of 300 km2.
Habitat and Ecology
It is a variable species, with individuals capable of reaching sexual maturity either in the metamorphosed or larval stage. Metamorphosed individuals spend most of the time on land in grassland habitat. It breeds in streams, lakes and moderately deep reservoirs.
Since the species was last assessed (2008), the species has been recorded in the three lagoons of the Ciénegas de Lerma protected area. Populations in one of the lagoons seems relatively healthy, and for the other two lagoons there are records of malformations and pollution, where the sub-populations are decreasing.
The extremely high degree of pollution of the rivers and pools where this species breeds has contributed to its decline. There is also a serious problem of habitat loss due to urban expansion. In addition, animals have been captured for food consumption and for medicinal purposes, and introduced predatory fish and the American Bullfrog (Lithobates catesbeianus) might also be a threat.
This species occurs within the three lagoons of the Ciénegas de Lerma Protected Area and is protected under the category Pr (Special protection) by the Government of Mexico.
Conservation of the lagoons, through the implementation of a sound management plan, is a priority. This should include habitat restoration actions, measures to reduce pollution, both from urban effluents and industrial effluents, and control measures for introduced or invasive species. A species management plan should be developed and implemented, ideally together with protected area managers and local communities. The species is amenable to breeding in captivity, and this should be considered in the conservation plans.
A monitoring program to follow the population trends is recommended.
Red List Status
Listed as Endangered because its extent of occurrence is 303 km2, its area of occupancy is 300 km2, all individuals are in a single threat-defined location, and field work undertaken since the species was last assessed (2008) confirmed the continuing decline in the extent and quality of its habitat and number of mature individuals.
Additional work differentiating this species from nearby populations of Ambystoma velasci is needed (Shaffer and McKnight 1996).
IUCN SSC Amphibian Specialist Group 2015. Ambystoma lermaense. The IUCN Red List of Threatened Species 2015: e.T1093A53947147. http://dx.doi.org/10.2305/IUCN.UK.2015-4.RLTS.T1093A53947147.en .Downloaded on 22 January 2019