CRITTERS: Climate, Resource, and Image Tracking in Tiny, Ecologically Representative Systems

1. Conservation and ecology research and practice is most effective when theory and models that underly species management are well explored and understood in experimental systems. Microcosm studies can provide experimental evidence to support theory, test model performance in different conditions, and suggest generality. However these benefits have been limited to primarily extinction and population studies, while habitat models have largely remained unexplored in newer systems. 2. There is presently lacking an experimental system that uses benchtop temperature and food manipulation combined with automated, in situ non-destructive sampling – necessary for conducting habitat and spatial structure studies in microcosms. 3. We developed Climate, Resource, and Image Tracking in Tiny, Ecologically Representative Systems (CRITTERS), an experimental microcosm system that manipulates habitat through abiotic temperature and biotic components (resources) in a benchtop design, and automates data collection through in situ observations. We propose it as a system in which to test a variety of models and theories in conservation and ecology. 4. We present the counting accuracy of CRITTERS and population responses of Paramecium caudatum to the temperature and resource availability. Using a modified version of the software Wellcounter, the correlation between automated and manual counts was r = 0.98. In logistic models, P. caudatum growth rate r responded to temperature quadratically, and carrying capacity K responded to resources (concentration of carbon in media) log-linearly, allowing independent control of r and K. 5. This system can be used to test a variety of habitat models in which climate and/or resources require manipulation when in situ sampling and high replication is important. We describe potential uses for testing adaptive management strategies, occupancy and N-mixture models, and Species Distribution Models.