Twenty years and counting with SADIE: Spatial Analysis by Distance Indices software and review of its adoption and use

SADIE (Spatial Analysis by Distance Indices) is designed specifically to quantify patterns in spatially-referenced count-based data. It was developed for dealing with data that can be considered ‘patchy’. Such distributions are commonly found, for example, in insect populations where discrete patches of individuals are often evident. The distributions of such populations have ‘hard edges’, with patches and gaps occurring spatially. In these cases variance of abundance does not vary smoothly, but discontinuously. In this paper we outline the use of SADIE and provide free access to the SADIE software suite, establishing Rethinking Ecology as its permanent home. Finally, we review the use of SADIE and demonstrate its use in a wide variety of sub-disciplines within the general field of ecology.