Speciation (Box 1) is the engine generating new biodiversity, and not only many species but the process of speciation itself is under threat from ongoing human activities (Barnosky et al. 2011). Studies have found that human impacts can both hinder and promote speciation, which has important implications for the long-term recovery of Earth’s biodiversity (Rosenzweig 2001). Both variation in speciation rate among lineages and the amount of time and area available for speciation to occur can influence the size of regional species pools (Rabosky 2020; Miller & Román‐Palacios 2021) and community diversity assembled from it. This process can also add species to communities directly via in situ speciation (e.g., Gillespie 2004). However, despite an increasing focus on speciation as a driver of community diversity, less attention has been paid to how local and regional dynamics of speciation differ among terrestrial and freshwater habitats, and how these dynamics are altered by human impacts (Figure 3, Table 1). It should be noted that while the products of speciation can be quickly eradicated, recovering new species via this process occurs over longer timescales and is outside the scope of many traditional conservation approaches.