Response to Delhey et al

Predicting how organisms will respond to future climate change is a challenging task for biologists. In general, there are three ways to make such biotic predictions. First, by manipulating climatic conditions, such as temperature, humidity, etc. in laboratory experiments, it is possible to observe how adaptation or extinction occurs. Second, historical data can be synthesised using a meta-analysis to test for any relationship between biotic changes and climatic warming since the industrial revolution. Lastly, theoretical trends in biotic change can be associated with observed spatial variation (where, for example, climatic gradients result in spatial variations equivalent to climate changes).