Just as in other fields in biology, ecologists use a mixture of observations, experiments, and models to test ecological theories (see Key Concept 1.2). Ecologists are unique, though, in using a wide range of venues and scales in their experiments, including short laboratory experiments, long-term field manipulations, and even decades-long ecosystem-wide experiments, such as the Biological Dynamics of Forest Fragments Project described in Key Concept 53.5. However, at large spatial scales or over long periods of time, well-replicated and controlled experiments are usually not possible. For example, when studying the ecological effects of climate change on a particular species, ecologists might have to combine observations of the temperature range of that species with short-term experiments on the effects of warming on the species’ distribution and then use models to project how distributions could change with continued warming. Often this type of research requires multiple techniques and collaborative efforts to be successful.