Lake Pátzcuaro (Spanish: ''Lago de Pátzcuaro'') is a
lake
A lake is often a naturally occurring, relatively large and fixed body of water on or near the Earth's surface. It is localized in a basin or interconnected basins surrounded by dry land. Lakes lie completely on land and are separate from ...
Michoacán
Michoacán, formally Michoacán de Ocampo, officially the Free and Sovereign State of Michoacán de Ocampo, is one of the 31 states which, together with Mexico City, compose the Political divisions of Mexico, Federal Entities of Mexico. The stat ...
, Mexico.
Lake Pátzcuaro lies in an
endorheic basin
An endorheic basin ( ; also endoreic basin and endorreic basin) is a drainage basin that normally retains water and allows no outflow to other external bodies of water (e.g. rivers and oceans); instead, the water drainage flows into permanent ...
, which does not drain to the sea. A watershed area of 929 square kilometres drains into the lake, of which 126.4 are the water body. The Lake Pátzcuaro watershed extends 50 kilometres east–west and 33 kilometres from north to south. Lake Pátzcuaro lies at an elevation of 1,920 metres, and is the center of the basin and is surrounded by volcanic mountains with very steep slopes. It has an average depth of 5 metres and a maximum of 11. Its volume is approximately 580 million cubic metres."Descripción de la cuenca", ''Recuperación Ambiental del Lago de Pátzcuaro''. Accessed October 18, 2009
The Lake Pátzcuaro basin is of volcanic origin. At times it has been part of an open and continuous hydrological system formed by Lake Cuitzeo, Pátzcuaro and Lake Zirahuén, which drained into the Lerma River. Today, like lakes Cuitzeo and Zirahuén, it is a closed basin, although ecologists consider it a sub-basin of the Lerma-Chapala basin.
Wetlands
The lake is surrounded by extensive
wetland
A wetland is a distinct semi-aquatic ecosystem whose groundcovers are flooded or saturated in water, either permanently, for years or decades, or only seasonally. Flooding results in oxygen-poor ( anoxic) processes taking place, especially ...
s, which have been designated as a
Ramsar site
A Ramsar site is a wetland site designated to be of international importance under the Ramsar Convention,8 ha (O)
*** Permanent 8 ha (P)
*** Seasonal Intermittent < 8 ha(Ts)
**
Cattails and other reedy vegetation are the dominant wetland vegetation, in dense stands over 2 meters tall. Typical wetland plant genera include ''
Typha
''Typha'' is a genus of about 30 species of monocotyledonous flowering plants in the family Typhaceae. These plants have a variety of common names, in British English as bulrushStreeter D, Hart-Davies C, Hardcastle A, Cole F, Harper L. 2009. ' ...
'', '' Scirpus'', '' Eleocharis'', and '' Cyperus''. The dominant species of aquatic vegetation are ''
Potamogeton illinoensis
''Potamogeton illinoensis'', commonly known as Illinois pondweed or shining pondweed, is an aquatic plant. It provides food and cover for aquatic animals.
It is generally not weedy in its native range, but it is a troublesome noxious weed in Vi ...
'', '' Scirpus pectinatus'', '' Typha latifolia'', '' T. domingensis'', and '' Nymphaea mexicana''.
The wetlands are extremely important for birds, both year-round inhabitants and migrating waterfowl. Close to 200 species inhabit the wetlands, including some endemic species such as the black-polled yellowthroat (''Geothlypis speciosa''). Two native species have not been observed recently; the yellow rail ''(Coturnicops noveboracensis)'' has not been seen since 1964 and may be locally extinct, and the endemic slender-billed grackle (''Quiscalus palustris'') is presumed extinct.
The Lake Pátzcuaro salamander (''Ambystoma dumerilii'') is
endemic
Endemism is the state of a species being found only in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also foun ...
to the basin. Among other aquatic or semi-aquatic animals, several are largely or entirely restricted to the Lake Pátzcuaro system, such as the rough-footed mud turtle of the subspecies ''tarascense'', the essentially harmless Mexican garter snake of the subspecies ''patzcuaroensis'', the fish Pátzcuaro chub (''Algansea lacustris'') and Pátzcuaro allotoca (''Allotoca diazi''), and the dwarf crayfish '' Cambarellus patzcuarensis''.
The lake and its surrounding wetlands have undergone significant environmental changes over the past 50 years. Logging and agriculture in the surrounding watershed have contributed to siltation of the lake (1 cm / year - 1.2 million cubic meters / year), and water diversion for agriculture and urbanization has reduced the size of the lake by 40 square kilometers, and 2.6 meters in depth. Other threats include untreated sewage, the introduction of exotic species, and chemical pollution."Indicadores del deterioro ambiental", ''Recuperación Ambiental del Lago de Pátzcuaro''. Accessed October 18, 2009 /ref>
In February 2021, members of the Supreme Indigenous Council of Michoacán (CSIM) noted that political opportunism, corruption, and a lack of coordination have undermined efforts to clean up the lake. They noted that since 2006 MXN $5 billion has been spent, and since 1934, 2,300 studies have been conducted, yet 79% of the inhabitants of Pátzcuaro, Erongarícuaro, Quiroga, and Tzintzuntzan live in poverty and 40% in
extreme poverty
Extreme poverty is the most severe type of poverty, defined by the United Nations (UN) as "a condition characterized by severe deprivation of basic human needs, including food, safe drinking water, sanitation facilities, health, shelter, ...
.
Watershed
In the watershed surrounding the wetlands, the natural terrestrial vegetation is composed of xeric scrub (1,920–2,100 m above sea level), pine and oak forests intertwined with xeric scrub (2,100–2,400 m) and by pure pine-oak forests in the higher peaks (2,400–2,900 m). The pine-oak forests are part of the Trans-Mexican Volcanic Belt pine-oak forests
ecoregion
An ecoregion (ecological region) is an ecological and geographic area that exists on multiple different levels, defined by type, quality, and quantity of environmental resources. Ecoregions cover relatively large areas of land or water, and c ...
.
In the last fifty years, human activity in the watershed has intensified. Farming and livestock ranching in the basin have significantly increased. Over 10,000 hectares of forest have been lost to logging, fires, fuelwood gathering, and clearance for farming and ranching.
History
The Lake Pátzcuaro basin is home to the
Purépecha people
The Purépecha ( ) are a group of Indigenous peoples of Mexico, Indigenous people centered in the northwestern region of Michoacán, Mexico, mainly in the area of the cities of Cherán and Pátzcuaro.
They are also known by the derogatory term ...
. Purépecha leaders established the basin as the heartland of the Tarascan state, which rivaled the
Aztec Empire
The Aztec Empire, also known as the Triple Alliance (, Help:IPA/Nahuatl, jéːʃkaːn̥ t͡ɬaʔtoːˈlóːjaːn̥ or the Tenochca Empire, was an alliance of three Nahuas, Nahua altepetl, city-states: , , and . These three city-states rul ...
* Jaracuaro
* Uranden - Small island.
* Janitzio - Island with tourist facilities
* Pacanda - The largest, flattest island. Cabanas for rent.
* Yunuen - Small island
* Tecuena - Sparsely populated island
Major towns along the lake shore
* Pátzcuaro - Situated on the southeastern shore of Lake Patzcuaro
* Erongarícuaro - Historic Purépecha site
* Quiroga - Thriving market town
* Tzintzuntzan - Market town with ruins nearby - Capital of the P'urhépechas