State Indicators

Polluted surface water bodies

The degree of contamination of a water body can be measured in monitoring stations through the concentration of certain pollutants. In Mexico, parameters monitored include the concentration of phosphates and nitrates (which cause eutrophication and thus the loss of aquatic biodiversity; Revenga et al., 2000; EEA, 2003; Silk and Ciruna, 2004) and biochemical oxygen demand (BOD, i. e. consumption of oxygen by bacteria that break down organic matter in water, which is  an indirect evidence of the amount of organic matter). The Biochemical oxygen demand in surface water is used as an indicator of water quality in Mexico’s surface water bodies; this indicator is used both by international organizations (e. g. OECD and UN) and by environmental ministries or agencies of many countries, including Mexico. The indicator is included in the chapter on Water under Quality.

Mexican freshwater species at risk

Due to the lack of data regarding the status of populations of species of flora and fauna in a country or region, lists of endangered species have been used by governments of many countries and NGOs as biodiversity indicators. Under this scheme, threatened species represent the actual or potential reduction of biodiversity of a given country or region (GESAMP, 1995; UNCSD, 1995; Revenga and Kura, 2003; Contreras-Balderas et al., 2004). The indicator Mexican freshwater species at risk shows the biodiversity of Mexico’s freshwater ecosystems. The use of the number of threatened species is widely recommended by various international organizations (e. g. OECD and UN) and environmental agencies or ministries of many countries, including Mexico.