It is well-known that humans are fundamentally altering the biodiversity and functioning of ecosystems through impacts such as habitat loss, climate change and biological invasions (Ruckelshaus et al. 2020; Pörtner et al. 2021). However, recent studies suggest that global change drivers may cause divergent biodiversity responses in terrestrial and aquatic ecosystems (Blowes et al. 2019; van Klink et al. 2020), making it difficult to forecast future biodiversity changes. Indeed, that differences exist in human impacts across ecosystems was a key finding of the recent IPBES Global Assessment (Díaz et al.2018; Ruckelshaus et al. 2020), which emphasized the importance of better understanding these differences. One potential reason the relative importance of human impacts may vary across ecosystems, beyond differing strength of impact, is that differences exist in the relative importance of core processes that govern biodiversity dynamics in these systems. Identifying differences in the strength and type of processes most important in a given ecosystem may allow for the development of comparative frameworks to understand and mitigate human impacts in both terrestrial and aquatic communities.