Biodiversity assessment mainly relies on two families of indices, the alpha indices that measure the diversity of a single unit, and the beta indices that estimate how two units differ. Alpha and beta indices are therefore used to assess within and between-group diversity respectively, a group being a site, a habitat or a time event. Recent developments at large ecological scales led to the development of several alpha acoustic indices (e.g. L_{i}, H_{i}, ACI, NDSI) to estimate the energy, the level of complexity or the composition of an acoustic community or a landscape. However, few beta indices have been developped when between-group metrics could be very useful to estimate the spatial and temporal heterogeneities of large scale acoustic units. In this talk, we will review the acoustic dissimilarity indices developed so far, detail their mathematical properties, pinpoint their advantages and potential bias, and illustrate their use in the analysis of temperate and tropical acoustic communities.