The last two decades have been a period of enormous growth of agent-based (or individual-based) (ABM) modeling in ecology. ABMs allow mechanistic detail to be represented for many aspects of variation of individual organisms. ABMs are suited to spatially explicit modeling of populations, communities, and ecosystems, taking into account both the complexity of the environment and the physiological and behavioral adaptations of organisms. Thus, ABMs can include links between effects of environmental factors on plants and animals and makes ABMs essential in projecting how climate change will affect ecological systems. Key studies using ABMs to both understand ecological systems and project future changes will be discussed. These ecological applications include forest dynamics, species conservation, and preservation of biodiversity. This will include a prognosis of the future directions.