PH097
Lake Lanao


Year of compilation: 2001

Site description
Lake Lanao is the second largest lake in the Philippines and the largest in Mindanao. It is a large, oligotrophic, freshwater lake, formed by the tectonic volcanic damming of a basin between two mountain ranges and the collapse of a large volcano. This IBA includes the lake itself and some extensive forest cover on its south and southeast shorelines. Some of the higher altitude forests of the Lake Lanao Watershed are included in the Butig Mountains (PH099) and Mt Piagayungan (PH098). There are extensive reed beds around the edges of the lake, and large areas of Eichhornia crassipes and other aquatic vegetation on the lake surface. Most of the surrounding areas have been cleared for agriculture but there is still some primary lowland dipterocarp forest on the nearby Sacred Mountain, and there are patches of secondary dipterocarp forest at Wao. The lake serves as a reservoir for the generation of hydroelectric power on the Agus River, which generates 70% of the electricity used by the people of Mindanao. It supports a major fishery, and is important for recreational activities including boating, swimming and sport fishing. There are several towns and many villages around it, and a Mindanao State University campus is situated there.

Key biodiversity
Several of the threatened and restricted-range species of the Mindanao and Eastern Visayas Endemic Bird Area have been recorded around Lake Lanao, all forest birds apart from Spot-billed Pelican and Philippine Duck. The pelican is extinct there, but Philippine Duck probably still occurs, as the lake is reported to support large numbers of waterfowl. It is likely that some of the old bird records from ‘near Lake Lanao’ were actually collected in, for example, the nearby Mt. Piagayungan (PH098) or the Butig Mountains (PH099). However, the limited area of lowland forest near the lake could still support some forest birds.

Non-bird biodiversity: Lake Lanao is of great limnological interest. The fauna includes many species of fishes and invertebrates that are endemic to the lake, and presents an outstanding opportunity for research on evolution in the Cyprinids. There are about twenty species of Cyprinidae endemic to the lake, but many of the other fishes occurring in the lake have been introduced.. Mammals occurring in the area include wild pig (probably Sus philippensis) and deer Cervus mariannus and many endemic small mammals.



Pressure/threats to key biodiversity
There are some major problems within the Lake Lanao Watershed, including land claims by migrants, cattle ranchers and rebel returnees. Other problems include illegal logging, small-scale mining and quarrying activities, and soil erosion leading to siltation and increased turbidity of the waterways and lake. Indigenous fishes in Lake Lanao are threatened by the introduction of exotic fish species, overfishing, domestic pollution and an increase in fertilizer use. The operation of the Maria Cristina hydroelectric dam (which is controlled by NAPOCOR) causes seasonal fluctuations in the water level of the lake and displacement of the fish and their breeding grounds. The construction of additional spillways for the hydro electric power station involves more dredging of river banks and destruction of riparian habitat.

Conservation responses/actions for key biodiversity
Following the creation of the Lake Lanao Watershed in 1992, the Lake Lanao Watershed Development Council was established to prepare a comprehensive protection and development plan. The Lake Lanao Watershed Development Program has been created to implement this 5-year development plan for Lake Lanao Watershed’s rehabilitation and protection. The Council has also proposed a Lake Lanao Watershed Research and Development Center. Hunting causes considerable disturbance on the lake, and there is some pollution from insecticides and herbicides. The introduction of exotic species of fishes has undoubtedly had negative effects on the unique native fish fauna. An environmental impact assessment has been carried out on the National Power Corporation's Hydro electric Project on the Agus River. There is a proposal to conduct further environmental impact assessments of all the hydro electric projects of the National Power Corporation on the Agus River and at Maria Cristina Falls. Surveys are required in this IBA, to investigate both the extent and quality of the remaining habitats and the current status of the threatened and restricted-range birds and other biodiversity.

Protected areas
The Lake Lanao Watershed (185,640 ha) was created by Proclamation No. 871 in February 1992.

Habitat and land use
Lake Lanao is the second largest lake in the Philippines and the largest in Mindanao. It is a large, oligotrophic, freshwater lake, formed by the tectonic volcanic damming of a basin between two mountain ranges and the collapse of a large volcano. This IBA includes the lake itself and some extensive forest cover on its south and southeast shorelines. Some of the higher altitude forests of the Lake Lanao Watershed are included in the Butig Mountains (PH099) and Mt Piagayungan (PH098). There are extensive reed beds around the edges of the lake, and large areas of Eichhornia crassipes and other aquatic vegetation on the lake surface. Most of the surrounding areas have been cleared for agriculture but there is still some primary lowland dipterocarp forest on the nearby Sacred Mountain, and there are patches of secondary dipterocarp forest at Wao. The lake serves as a reservoir for the generation of hydroelectric power on the Agus River, which generates 70% of the electricity used by the people of Mindanao. It supports a major fishery, and is important for recreational activities including boating, swimming and sport fishing. There are several towns and many villages around it, and a Mindanao State University campus is situated there.


Recommended citation
BirdLife International (2017) Important Bird Areas factsheet: Lake Lanao. Downloaded from http://www.birdlife.org on 23/07/2017.