Cauca Valley Dry Forests

The apical flycatcher is an opportunist and has been able to eke out a living in the remaining patches of gallery forest along the steep river canyons of the Cauca Valley in Colombia. As its name suggests, it is a professional fly catcher, and does so in acrobatic ways by “hawking” insects inside the forest and forest-agricultural edges. Although much of the original dry forest has long since been converted to human use, some species have managed to adapt while others are restricted to small patches, usually on steep inaccessible slopes. The apical flycatcher is symbolic of the hope that nature will return to this and other dry Andean valleys.

This dry inter-Andean valley is located between the west and central Andes in Colombia. This ecoregion consists of a narrow, elongated, north-south strip of dry forest habitat along the Cauca River in the Valley and Risaralda departments. This Andean valley region ranges in altitude from 200 to 1,700 m.  There are various vegetation formations, including open woodland, dry forest, riparian forest, arid scrub, and wetlands. 

The vegetation in this ecoregion was historically deciduous dry forest, mixed with evergreen dry forest and arid scrubland, with gallery forests along the Cauca River and its tributaries. On either side of the valley, these dry forests give way to moist montane forest along the slopes of the central and western Andes. More specific information about the native flora in this ecoregion is not available. Today, agriculture has severely altered the environment and the now predominant secondary vegetation in the area includes Cecropia, Cestrum, Inga, Croton, Isertia, Trema, and Vismia. 

Little is known of the flora and fauna native to this valley. Some restricted-range birds have been found in the El Cauca Valley and also in surrounding ecoregions. The white-chested swift (classified as Vulnerable) inhabits secondary forest, grassland, scrub, and rocky areas in the Cauca Valley. The greyish piculet and apical flycatcher are found in tropical deciduous and secondary forest, tropical lowland evergreen forest edge, and scrub. These three species are adapted to scrub and secondary growth, so their numbers have not declined, with the exception of the white-chested swift, a species apparently threatened by agrochemical applications in the region.

The ecoregion has been almost entirely converted to agricultural land. Remaining unprotected areas of the original vegetation are few and small. The Sonso Lagoon Reserve is the only protected area located in an ancient oxbow of the Cauca River, consisting of 20.5 km² of wetlands and forests. The species found in the reserve are representative of wetlands and gallery forests. There are no protected areas in the dry forests.

There has been extensive habitat loss due to agriculture and urban development in the Cauca Valley region. Because of this development, there are many urban centers such as the city of Cali and a number of other cities and towns that line the Cauca Valley and River. Increased agriculture has led to increased application of agrochemicals, which threatens species such as the white-chested swift, although the actual extent of effects are still unknown. 

The priority conservation actions for the next decade will be to: 1) establish and extend protected areas within this ecoregion in order to prevent further deforestation, 2) restore historical vegetation; and 3) limit land conversion practices. 

Citations 

1. Instituto Geográfico "Agustin Codazzi". 1976. Mapa ecológico de la República de Colombia. Ministerio de Hacienda y Crédito Público. Bogotá, Colombia
2. Stattersfield, A.J., M.J. Crosby, A.J. Long and D.C. Wege. 1998. Endemic Bird Areas of the World: Priorities for Biodiversity Conservation. Birdlife Conservation. Series No. 7., Birdlife International, Cambridge, UK.
3. Navarro, A.E.S., G.H. Peña, F.C. Lemus, J.R. Baquero, R.F. Soto. 1984. Bosques de Colombia. IGAC-INDERENA-CONIF, Bogota, Colombia.