The ecological and evolutionary responses of groups of species to environmental change

Abstract

The natural environment is being altered by anthropogenic activity at an unprecedented rate. The effects of climate change and damage caused by other human activities show little sign of decelerating. The ubiquity of the forecast changes means that all species are likely to face alterations in their environment and consequently may have to migrate or adapt to avoid extinction. Yet, as species respond they may initiate additional ecological changes, creating further selection pressures on species they interact with. Research has shown that ecological and evolutionary dynamics such as these occur on the same time-scale and produce dynamics that cannot be explained if evolution is ignored. Thus, to understand and predict how species will respond to environmental change, it is important to consider both ecology and evolution and the feedback between them. In this thesis I investigate the ecological and evolutionary responses of groups of species to a number of environmental changes using experimental evolution with naturally co-occurring bacteria and mathematical modelling. After reviewing and introducing the field in Chapter 1, in Chapter 2 I investigate the effect of species diversity on evolution to a novel environment. In Chapters 3 and 4 I report on the results of a field experiment in which I manipulated immigration into diverse microbial communities while exposing them to experimental warming. Specifically, in Chapter 3 I investigate how warming and immigration affect local adaptation and also whether the local adaptation of the community is predictable from that of component species and in Chapter 4 I discuss the impact of warming on predictability. Finally, in Chapter 5 I use mathematical modelling to explore how species’ evolutionary responses to stress affect their interspecific interactions. My research places particular emphasis on the importance of species interactions to evolution and, furthermore, how these changes in biotic interactions affect ecosystem functioning.