Urban structure changes and environmental factors of valencian community towns as potential drivers of the house sparrow decline

Laburpena

The House Sparrow Passer domesticus (Linnaeus, 1758) is on decline almost all over Europe. In Spain, the case of the Valencian Community, the study area of this thesis, stands out with decreases of over 95% in rural areas and 70% in urban areas. The causes of the decline in urban areas are still unclear. In the towns and cities of the Valencian Community, important processes of transformation of the urban structure, which affect the availability and suitability of the habitat for the species, are taking place. The aim of this thesis was to explore these changes as potential drivers of the decline of the House Sparrow. The thesis is divided into 8 chapters. Chapter 1 contains an overview of the biology and status of the House Sparrow in Europe, Spain, and the Valencian Community. Chapter 2 focused on describing the urban characteristics of contemporary cities that affect urban birds from a holistic perspective. In chapter 3 were studied the main factors that determine the abundance of the house sparrow in urban areas of the Valencian Community, such as parks and surface rubbish containers. In Chapter 4 it was found that the remodelling of urban parks with artificial substrates, such as artificial grass, caused population declines of 60% compared to 15% of traditional parks without remodelling. In Chapter 5 it was reported that replacing surface dumpsters with underground dumpsters could have a negative effect on the species. Chapter 6 concerns a study in captivity that found that the urban diet is capable of increasing oxidative stress in individuals, even in an environment without contamination. Chapter 7 of the thesis showed that the recreational noise of the Moors and Christians festivities in spring significantly reduced the breeding success of the House Sparrow. Chapter 8 summarizes and integrates the information from the entire thesis and also includes a series of urban planning and management measures to alleviate the decline of the House Sparrow in the Valencian Community. Keywords: decline, diet, House Sparrow, parks, Passer domesticus, recreational noise, remodelling, trash containers, urban areas, urbanization.