Colombian Grebe
Encyclopedia
The Colombian Grebe was a grebe
(aquatic bird) found in the Bogotá wetlands in the Eastern Andes
of Colombia
. The species was still abundant on Lake Tota
(3000m) in 1945. The species has occasionally been considered a subspecies of Black-necked Grebe
(P. nigricollis).
The decline of the Colombian grebe is attributed to wetland drainage, siltation
, pesticide
pollution
, disruption by reed harvesting, hunting, competition, and predation of chicks by rainbow trout
(Salmo gairdneri) (del Hoyo et al. 1992). The primary reason was loss of habitat: drainage of wetlands and siltation resulted in higher concentrations of pollutant, caussing (eutrophication
) across Lake Tota
. This destroyed the open, submergent pondweed
(Potamogeton) vegetation and resulted in the formation of a dense monoculture
of water weed (Elodea) (Varty et al. 1986, Fjeldsa 1993, as cited in O'Donnel and Fjeldsa 1997).
By 1968 the species had declined to approximately 300 birds. Only two records of this bird was made in the 1970s; one seen 1972, and the last confirmed record from 1977 when three birds were seen. Intensive studies in 1981 and 1982 failed to find the species and it is now considered extinct.
Grebe
A grebe is a member of the Podicipediformes order, a widely distributed order of freshwater diving birds, some of which visit the sea when migrating and in winter...
(aquatic bird) found in the Bogotá wetlands in the Eastern Andes
Andes
The Andes is the world's longest continental mountain range. It is a continual range of highlands along the western coast of South America. This range is about long, about to wide , and of an average height of about .Along its length, the Andes is split into several ranges, which are separated...
of Colombia
Colombia
Colombia, officially the Republic of Colombia , is a unitary constitutional republic comprising thirty-two departments. The country is located in northwestern South America, bordered to the east by Venezuela and Brazil; to the south by Ecuador and Peru; to the north by the Caribbean Sea; to the...
. The species was still abundant on Lake Tota
Lake Tota
Lake Tota is the largest lake in Colombia, located in the east of Boyacá department. It has an area of 55 km² and a depth of 60 meters.The major town on the lake is Aquitania, located on its eastern side. Other nearby villages include Tota, Iza and Cuitiva. Lake Tota was an important religious...
(3000m) in 1945. The species has occasionally been considered a subspecies of Black-necked Grebe
Black-necked Grebe
The Black-necked Grebe, Podiceps nigricollis, known in North America as the Eared Grebe, is a member of the grebe family of water birds. It occurs on every continent except Australia and Antarctica.-Taxonomy:There are three subspecies:*P. n...
(P. nigricollis).
The decline of the Colombian grebe is attributed to wetland drainage, siltation
Siltation
Siltation is the pollution of water by fine particulate terrestrial clastic material, with a particle size dominated by silt or clay. It refers both to the increased concentration of suspended sediments, and to the increased accumulation of fine sediments on bottoms where they are undesirable...
, pesticide
Pesticide
Pesticides are substances or mixture of substances intended for preventing, destroying, repelling or mitigating any pest.A pesticide may be a chemical unicycle, biological agent , antimicrobial, disinfectant or device used against any pest...
pollution
Pollution
Pollution is the introduction of contaminants into a natural environment that causes instability, disorder, harm or discomfort to the ecosystem i.e. physical systems or living organisms. Pollution can take the form of chemical substances or energy, such as noise, heat or light...
, disruption by reed harvesting, hunting, competition, and predation of chicks by rainbow trout
Rainbow trout
The rainbow trout is a species of salmonid native to tributaries of the Pacific Ocean in Asia and North America. The steelhead is a sea run rainbow trout usually returning to freshwater to spawn after 2 to 3 years at sea. In other words, rainbow trout and steelhead trout are the same species....
(Salmo gairdneri) (del Hoyo et al. 1992). The primary reason was loss of habitat: drainage of wetlands and siltation resulted in higher concentrations of pollutant, caussing (eutrophication
Eutrophication
Eutrophication or more precisely hypertrophication, is the movement of a body of water′s trophic status in the direction of increasing plant biomass, by the addition of artificial or natural substances, such as nitrates and phosphates, through fertilizers or sewage, to an aquatic system...
) across Lake Tota
Lake Tota
Lake Tota is the largest lake in Colombia, located in the east of Boyacá department. It has an area of 55 km² and a depth of 60 meters.The major town on the lake is Aquitania, located on its eastern side. Other nearby villages include Tota, Iza and Cuitiva. Lake Tota was an important religious...
. This destroyed the open, submergent pondweed
Pondweed
Pondweed refers to many species and genera of aquatic plants and green algae:*Potamogeton, a diverse and worldwide genus*Elodea, found in North America*Aponogeton, in Africa, Asia and Australasia*Groenlandia, a genus of aquatic plants...
(Potamogeton) vegetation and resulted in the formation of a dense monoculture
Monoculture
Monoculture is the agricultural practice of producing or growing one single crop over a wide area. It is also known as a way of farming practice of growing large stands of a single species. It is widely used in modern industrial agriculture and its implementation has allowed for large harvests from...
of water weed (Elodea) (Varty et al. 1986, Fjeldsa 1993, as cited in O'Donnel and Fjeldsa 1997).
By 1968 the species had declined to approximately 300 birds. Only two records of this bird was made in the 1970s; one seen 1972, and the last confirmed record from 1977 when three birds were seen. Intensive studies in 1981 and 1982 failed to find the species and it is now considered extinct.