Abstract

GARITANO ZAVALA, Álvaro  and  GISMONDI, Paola. Variation of the richness and diversity of the birds in urban green areas of the La Paz and El Alto cities (Bolivia). Ecología en Bolivia [online]. 2003, vol.38, n.1, pp.65-78. ISSN 1605-2528.

In urban ecosystems the original biodiversity diminishes considerably, but an associate biota exists that can be indicative of environmental quality. Considering 27 urban green areas in the cities of La Paz and El Alto as sample units, avian species richness and diversity were determined and related using linear regressions with the following environmental factors: surface area, percent of vegetation cover, altitude above sea level, and density of the introduced dove Columba livia. We recorded a total of 34 bird species. Species richness varied from 2 to 31 species, and diversity indices between 0.64 and 2.67. Only five green areas (19%) had 10 or more bird species, and only two (7%) more than 20 species. Six areas (22%) contained only synanthropic species. Bird communities in the richest green areas had few abundant and numerous uncommon species. Diversity and species richness diminish when the altitude and density of C. livia increase, but increases if the surface area and vegetation cover are greater. The factor that best explained the variation in bird diversity was the proportion of vegetation cover, and the species richness was be best explained for the density of C. livia. These results demonstrate that bird diversity and richness are low in the cities of La Paz and El Alto, partly because few green areas have a surface area greater than 10 000 m² and a vegetation cover greater than 50%. This demonstrates the poor planning in the urban growth of the two cities studied, which does not only affect avian diversity, but also the physical and mental health of citizens in the long term.

Keywords : urban birds; altitudinal distribution; urban planning; human impact; Andes.

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