Caves as simplified settings for testing ecological theory

Community assembly, how it changes in space and time, and how it will be affected by global threats, is one of the most pressing issues in ecology, evolution, and conservation biology. To fully understand assembly rules and future community change, one has to delve into multiple interrelated factors, such as the history of environmental and habitat changes in the past, current biotic and abiotic factors, spatial constraints, and future scenarios for all these. Yet, two factors have prevented us from obtaining a complete picture for any organism or system. First, communities are utterly complex, typically encompassing thousands of species and millions of interspecific interactions. Second, future scenarios are overwhelming to model without the challenge of dealing with chaotic systems, where even small changes can lead to large, unpredictable, consequences. We propose to use cave communities as the simplest and easiest setting to model assembly rules and future change across space and time. Caves offer unique opportunities for eco?evolutionary studies because they are characterized by a low abundance and diversity of organisms and interactions, they receive limited external inputs, and are easily modelled. The potential of subterranean systems as "natural laboratories" for exploring general, non?cave specific agendas has emerged in recent years, with many cave?based studies starting to resonate outside caves.