Efectos de las características de parche de bosque nativo sobre la riqueza de aves en ambientes degradados en la región de los ríos-Chile

Abstract

The footprint of human activity on the environment - sometimes known as global change - according to Steffen et al. (2004) has led some scientists to suggest that the earth has gone from a current geological time of the Holocene to enter a new age called the Anthropocene. This new era is associated with the transformation of the earth as a result of human actions, which has triggered situations that require prompt attention. In this sense, the new challenge facing the world is global change, which can be understood as the process of alteration of the environment due to anthropic activity with repercussions on biophysical components and effects on socioeconomic systems. For Vitousek (1994) there are three main components of global change: the first is the increase in carbon dioxide concentrations in the atmosphere, which is related to changes in the structure and dynamics of populations, the use excessive energy produced by industrialization, as well as the exploitation of natural resources; the second is the alteration of the nitrogen cycle, associated to the use of fertilizers for agricultural production and the burning of fossil fuels, which has generated chemical change at local and global level (Vitousek et al., 1997) and thirdly the change in land cover and use as a result of urban growth and the expansion of the agricultural frontier towards forest areas. The change in soil cover is described as the transformation of the biophysical attributes of the surface of the land, while land use is defined by the functionality that man gives to it, whether for agricultural use, of livestock or of exploitation (Lambin et al., 1999). 2 Sala et al. (2000) notes that the intensity of human activities has led to changes in land use and cover, which have accumulated on a global scale affecting the functioning of ecosystems with impacts on biodiversity. is considered one of the main consequences of soil degradation, in this sense, Vitousek et al. (1997) points out a decrease in the capacity of ecosystems to support human needs. Habitat loss and fragmentation are the main causes of changes in the distribution and abundance of organisms. These processes negatively influence species richness according to Zaviezo et al. (2006). The above concepts have been interpreted in an ambiguous way which has led to erroneous conclusions in the research processes (Summerville and Crist 2001, Swenson and Franklin 2000). In this sense, habitat loss refers to the decline in the extent of natural habitat, while habitat fragmentation is a landscape-scale process involving both habitat loss and habitat disruption (Fahrig, 1997, 2003) . For other researchers such as With et al., 1997; Young and Jarvis 2001 and Morante et al., 2015 the fragmentation process is related to the interruption of the connectivity of the landscape which translates into smaller fragments and their negative effects on biodiversity. Biodiversity loss is a concern worldwide, its main cause is related to habitat destruction, which has reduced the likelihood of successful breeding and feeding behavior of species, this is caused by the change in the use of land mainly, making it one of the most damaging threats to conservation because the survival of populations in fragmented landscapes depends to a great extent on the structural and functional integrity of the landscape (Fahrig, 2003).