Resumen de Responses of animal populations and communities to climate change and land-use shifts
Regino Zamora, José Antonio Hódar Correa, Antonio Jesús Pérez Luque, José Miguel Barea Azcón
Changes in the distribution and abundance of animal populations and communities signal a clear response to environmental alterations. A number of changes in climate and land use are taking place in the Sierra Nevada, such as higher temperatures and greater forest cover. In this chapter, we analyse the responses of animal populations and communities to these changes, for which long-term data are available in Sierra Nevada. In the first part of the chapter, several examples illustrate spatio-temporal changes in the distribution and abundance of bird communities (passerines) in 3 types of habitats for which information has been available since the 1980s: (1) Oak groves, (2) high-mountain juniper, (3) high-mountain summits. The results indicate a continuous turnover within the bird community, in an ecological setting that has changed little, especially in the high-mountain scrubland and summit areas. Moreover, the results also show a sharp decrease in bird density during the 40-year study period, chiefly affecting the dominant species of the 1980s in the Pyrenean oak woodland and in the high-mountain juniper scrubland. The outcome of these processes is a community in continuous flux, both in composition and abundance. The second part uses the pine processionary moth (Thaumetopoea pityocampa) as a biological sensor of the changes occurring in the climate and land use, considering not only spatial (elevational as well as regional) but also temporal. The pine processionary moth (T. pityocampa) exemplifies the way in which some defoliators of Spanish forests benefit from global warming and land-use change. As its larvae develop during the winter, higher temperatures may benefit this insect, accelerating its development. The analyses confirm such benefits due to rising temperatures in the medium–high elevations of Sierra Nevada, since the climate there has been the most limiting factor for this pest until now, as natural predators are scarce at these altitudes and it is also the area where most of the pine plantations are found.
