Paleolimnological evidence of global change in high mountain ecosystems of Sierra Nevada

Abstract

In this thesis, we seek a deeper and broader understanding of how Mediterranean alpine ecosystems responds to global change impacts over the past ~200 years. High mountain lakes constitute an excellent witness of global change and are amongst the most sensitive ecosystems to anthropogenic climatic change and environmental changes. Nowadays, changes in air temperature and precipitation have direct effects on the physical, chemical, and biological characteristics of high mountain lakes, and indirectly by modifying in-lake and catchment processes. In this thesis, we show that Mediterranean high mountain ecosystems experience major changes in response to recent warming. Besides, the interaction between factors of global change promotes a series of direct and indirect effects able to affect changes in biotic community composition and in the functioning and structure of alpine ecosystems. Spread over four data chapters, we explore distinct potential drivers of local to regional-scale variability in the climate response of biological and geochemical variables in the Sierra Nevada. More specifically, we study the effects of climate-driven changes (such us ice cover duration, water residence time or water temperature, among others) in the ecology and environment in an alpine lake and its catchment, as well as the interaction between climate and nutrient inputs in biological communities, and the role of lake-specific characteristic in the distribution of subfossil cladocerans across Sierra Nevada lakes.