Paleoecology

[Sully]

From the study posted above. It makes sense that the reduction in the mammoth steppe and warming temperatures were detrimental to grazers and mixed feeders, and as such browsers weren't as heavily impacted.

"We find that extinctions have removed the largest herbivores since the Late Pleistocene (Figure 1a), a trend also observed for megafauna in general (Smith et al., 2018). Consequently, current herbivore assemblages are down‐sized compared to the present‐natural assemblages that would have existed in the absence of human impacts (Figure 2a–b). Extinctions have also led to a decline in grazing herbivores. Even though they have lost fewer species in absolute terms, grazers have suffered relatively more extinctions than either mixed feeders or browsers (χ2 test of independence, χ2 = 9.18, df = 2, p = .01, Supporting Information Appendix Table S4.1). In total, grazers have lost 53% of their total species richness since the Late Pleistocene (48/90 species), whereas mixed feeders have lost 37% (65/177 species), and browsers have lost 36% (90/251 species) (Figure 1a). Most of these extinctions happened during the Late Pleistocene (Figure 1b). Grazers and mixed feeders, when compared to browsers, also possess a larger difference between their current and present‐natural‐ranges (Kruskal–Wallis, χ2 = 22.71, df = 2, p < .001, Supporting Information Appendix Table S4.2). On average, the current range of a grazing herbivore was 991,767 km2 smaller than their present‐natural range (median difference between current and present‐natural ranges). The range of a mixed feeder was 493,555 km2 smaller and the range of a browser was 65,186 km2 smaller. This suggests that grazers and, to a lesser extent, mixed feeders have experienced proportionally larger anthropogenic range restrictions than browsers have. As a result of the late Quaternary extinctions and extirpations, current wild herbivore assemblages are mostly dominated by herbivores with browsing diets (Figure 2c). In fact, wild grazers are absent from most of world’s terrestrial ecosystems (Supporting Information Figure S3.2)—contrasting strongly with the present‐natural scenario. Most present‐natural assemblages would have a more or less equal composition of grazing and browsing (Figure 2d). Wild herbivore assemblages where grazing is common still exist, but are rare and restricted to eastern Africa, Patagonia, parts of Central Asia, and Australia (Figure 2c). Australia appears to be an outlier, though. In contrast to most places, the continent has primarily lost browsing species (Figure 2c–d). Historically it also possessed relatively few large grazers (Australian herbivore species ≥ 500 kg: browsers: 6, mixed feeders: 1, grazers: 2)." Reply