Can a habitat specialist survive urbanization? the case of the viscacha (Lagidium viscacia, Chinchillidae)

Abstract

Urban growth is a strong driver of habitat degradation and loss. In spite of that, a surprising diversity of native species may survive in urban areas. In the La Paz, Bolivia metropolitan area and surroundings, local populations of “viscachas” (Lagidium viscacia) currently survive in small, isolated habitat patches. We assessed 13 study sites in 1999, 2003, and 2007 to document the effects of urban growth on L. viscacia habitats. Degree of disturbance at the study sites increased more between 1999 and 2003 than it did between 2003 and 2007 due to patterns of urban expansion. Using satellite imagery we determined that the urban area increased 566 ha (from 1987 to 2001) mostly due to southward urban area expansion down the valley where the best viscacha habitats were located. Occupied patch area decreased 74 % between 1999 and 2007, accompanied by significant increases in patch edge-to-area ratios. Currently L. viscacia populations in La Paz are experiencing a habitat attrition process. If a current urban expansion plan for La Paz is approved, about 75 % of the remaining habitat may be lost to urban development in a short time, compromising the future viability of this species in the metropolitan area and surroundings. Environmental regulations to control urban growth of the La Paz metropolitan area are urgently required and constitute the only hope for the survival of L. viscacia in the city.