The paradox of forbs in grasslands and the legacy of the mammoth steppe

The grassland biome supports an enormous diversity of life and includes ecosystems used extensively by humans. Although graminoids lend grasslands their characteristic appearance, forbs are largely responsible for their taxonomic, phylogenetic, and functional diversity. In terms of abundance, however, forbs often play a subordinate role relative to graminoids. Yet this may be a relatively recent phenomenon; evidence is mounting that forbs comprised a major part of the richness of, and were abundant in, the extensive and highly productive grasslands of the Pleistocene, the so-called mammoth steppe. As a legacy of their past prevalence under intensive grazing by megafaunal herbivores, we hypothesize that forbs were, and still are, dependent on niche construction by large mammalian herbivores. We suggest that the high species richness of forbs in grasslands globally merits greater research and conservation attention, and management actions tailored to sustain their abundance and diversity.

Automated summary

The grassland biome supports a diverse range of life, with forbs playing a key role in the taxonomic, phylogenetic, and functional diversity. Evidence suggests that forbs were abundant in the Pleistocene grasslands and may still rely on niche construction by large herbivores. Greater research and conservation efforts are needed to sustain the abundance and diversity of forbs in grasslands globally.