Lake Titicaca ecology
Lake Titicaca, situated at an elevation of 12,500 feet in the Andes Mountains, is renowned as the world's highest navigable lake and a significant ecological and cultural site. Spanning over 3,200 square miles, it is one of the few ancient lakes globally, estimated to be 3 million years old. The lake supports a unique hydrological system that includes various interacting basins, with significant seasonal fluctuations in water levels due to climate variability. Despite its rich biodiversity, including endemic species like the Lake Titicaca frog and a variety of aquatic and avian life, invasive species and pollution pose serious threats to the native ecosystem.
The region's inhabitants, notably the Aymara people, have lived around the lake for thousands of years, relying on traditional agriculture, fishing, and livestock herding. However, high poverty levels lead to challenges such as poor nutrition and health issues, complicating efforts for environmental and socioeconomic improvement. Historical human activities have altered the landscape, resulting in reduced vegetation and increased salinity in the lake. Collaborative efforts between Peru and Bolivia aim to address these ecological concerns, focusing on sustainable resource management and community development, although the ongoing impact of poverty remains a significant barrier to progress.
Lake Titicaca ecology
Category: Inland Aquatic Biomes.
Geographic Location: South America.
Summary: Lake Titicaca is the highest commercially navigable lake in the world.
Lake Titicaca is always described first as the world’s highest navigable lake. It is at an elevation of 12,500 feet (3,810 meters). Nestled in the Andes Mountains about halfway along the north-south spine of South America, this prehistoric lake was the cradle of Peru’s ancient civilizations and has been inhabited continually for 10,000 years.
The primary economic activities today mirror those from past centuries. Inhabitants fish in the lake’s icy waters; exist as subsistence farmers in the poor, rocky soils around the lake; or herd llamas and alpacas on slopes that leave visitors gasping for air. Despite the combined efforts of joint Peruvian and Bolivian legislative bodies, sociocultural improvements lag environmental gains, because of a high level of poverty in the region.
The lake is located at the northern end of the high plateau, or altiplano, region between two ranges of the Andes Mountains. The ring of high peaks surrounding the plateau creates a closed hydrological system referred to as the TDPS system, which encompasses four interacting basins: Lake Titicaca (T), the Desaguadero River (D), Poopó Lake (P), and Coipassa Salt Lake (S). Lake Titicaca is the largest portion of this system, sitting directly on the border between Peru to the west and Bolivia to the east.
Hydrology and Climate
The lake itself is the second-largest in South America, after Lake Maracaibo, spanning 3,200 square miles (8,288 square kilometers). It ranges more than 120 miles (193 kilometers) in a northwest-to-southeast direction and is 50 miles (80 kilometers) across at its widest point. A narrow strait, Tiquina, nearly separates the lake into two bodies of water. The larger portion to the north is called Lake Chucuito in Bolivia and Lake Grande in Peru. The smaller body to the south is known as Lake Huiñaymarca in Bolivia and Lake Pequeño in Peru.
Lake Titicaca is one of fewer than 20 ancient lakes in the world. It is estimated to be 3 million years old and was formed by both tectonic activity and glaciation. The lake currently averages 460–600 feet (140–183 meters) in depth, but the bottom tilts sharply toward the Bolivian side, reaching a maximum recorded depth of 920 feet (280 meters) off Isla Soto in the northeast corner.
However, the lake level fluctuates both seasonally and cyclically over periods of several years. The water level rises during the rainy season (December through March) and recedes through the dry winter months. More than 25 rivers empty into Titicaca, but only one small river, the Desaguadero, drains the lake, at the southern end. A total of 95 percent of the water in the system is lost by evaporation from the fierce winds and strong sun of the arid altiplano. The high rate of evaporation results in a slight increase in salinity annually.
Titicaca has a cold but tropical climate with moderate seasonal changes. Precipitation varies widely across the region, with more humid Lake Titicaca receiving approximately 55 inches (1,397 millimeters) of rain per year, while the arid Coipasa Salt Lake to the south receives only about 7 inches (178 millimeters). Unequal precipitation levels present challenges to water-distribution efforts throughout the area, but the greater issue is variability from year to year. It is not unusual here for a year of severe drought to be followed by a year of extreme flooding.
Biodiversity
A limited variety of animal populations inhabit Lake Titicaca. Two species of killifish (Orestias) and a catfish (Trichomycterus) were the principal inhabitants of the lake until the 1930s, when trout and mackerel were deliberately introduced for their high economic value. Populations of some native fish species are now vulnerable due to the competition generated by these and other invasive species.
Relatively few mammals live around the lake. Species that have adapted to the high elevation and extreme temperatures include Andean camelids such as the vicuña, llama, guanaco, alpaca, puma, and Andean fox. Avian life is far more prolific. More than 60 resident bird species share the grasslands, forests, and wetlands of the Titicaca basin with many migratory species.
The most recognized amphibian is the Lake Titicaca frog, or giant frog. Growing nearly 1 foot (0.3 meter) long, this loose-skinned frog spends much of its life under rocks in the marshy edges of the lake.
Effects of Human Activity
Ruins along the shore and on many of the 41 islands in the lake provide evidence of continuous human occupation dating back to approximately 10,000 b.c.e. The Aymara people living in the Titicaca basin still practice their ancient agricultural methods on stepped terraces that predate the Incan culture. Barley, oats, alfalfa, quinoa, and potatoes, along with other legumes and tubers, are common crops. Yields are often low due to the harsh climate and primitive farming methods.
Simple agriculture, fishing, and herding livestock such as llamas and alpacas are the main economic activities in the Titicaca region. Poverty and its associated problems such as poor nutrition, health issues, illiteracy, lack of sanitation, and a fragile environment combine to make it nearly impossible to improve the lives of the population.
Humans have had a great effect on the delicate environment of the TDPS system. Before 1000 c.e., the high plateau was covered with native forest. Around 1100 c.e., a severe 80-year drought changed the surface cover, and the forest disappeared. After 1500 c.e., damaging agricultural practices and imported livestock permanently altered the native vegetation.
In the past century, humans have had little additional effect on the environment, primarily due to the arid environment and lack of vegetation. Natural climate change appears to have impacted the region the most, creating periods of heavy rain and inundations, offset by drought. Studies have found that climate factors account for about 80 percent of the lake’s fluctuating wa-ter level, while irrigation accounts for the remaining 20 percent.
Future of the Titicaca Region
Despite the historical significance of this region, its future is uncertain. Irregular precipitation and extreme hydrological events limit governments’ ability to plan for economic development. Currently, high levels of pollution from the few urban centers and from mining operations in the region are affecting the watershed. The high level of poverty within the TDPS region is responsible for the lack of education and new technology, resulting in overexploitation and inefficient use of land and water resources.
The surface of Lake Titicaca and the entire watershed are evenly distributed between Peru and Bolivia, ensuring integrated stewardship of the entire hydrologic system. Since the 1950s, the countries have been developing a shared vision for environmental protection and socioeconomic development.
A master plan was created with the cooperation of the European Community from 1991 to 1993. Titled the Master Plan for Flood Prevention and the Usage of Water Resources of the TDPS System, this document consists of a framework for future development of the entire biome. It focuses on three key components: creating a system for the sustainable use of natural resources; reestablishing ecological integrity by protecting endangered species, and by mitigating human effects on the system; and promoting human development within the basins. There has been measurable success already on the first two points, but until the issues of rampant poverty are addressed, human development in the Titicaca region will have a low level of success.
Bibliography
Binational Autonomous Authority of Lake Titicaca. “Lake Titicaca Basin, Bolivia and Peru.” United Nations, 2003. http://www.unesco.org/new/en/natural-sciences/environment/water/wwap/case-studies/latin-america-the-caribbean/lake-titicaca-2003.
Dejoux, Claude and Andre Iltis. Lake Titicaca: A Synthesis of Limnological Knowledge. New York: Springer, 1992.
Lima-Quispea, Nilo, Marisa Escobar, Albertus J.Wickel, Manon von Kaenel, and DavidPurkeya. “Untangling the Effects of Climate Variability and Irrigation Management on Water Levels in Lakes Titicaca and Poopó.” Journal of Hydrology: Regional Studies, vol. 37, October 2021, doi.org/10.1016/j.ejrh.2021.100927. Accessed 29 Aug. 2022.
Revollo, Mario Francisco, Maximo Liberman Cruz, and Alberto Lescano Rivero. “Lake Titicaca: Experience and Lessons Learned Brief.” February 2006. http://www.ilec.or.jp/eg/lbmi/pdf/23‗Lake‗Titicaca‗27February2006.pdf.
Stanish, Charles. Lake Titicaca: Legend, Myth, and Science. Los Angeles, CA: Cotsen Institute of Archaeology Press, 2011.