Overlooked forbs: implications for rangeland biodiversity and function in southern Africa

Abstract

Forbs are a diverse component of grassy ecosystems, offering various vital ecosystem services while enhancing system resilience. However, herbaceous non-grass species are not routinely enumerated, nor their significance evaluated. We examined the extent to which grassland forbs have been considered by research published in the journals of the Grassland Society of Southern Africa (1966–2023). Searches for ‘forbs’ were conducted in the Taylor and Francis online database. Forbs were mentioned at least once in the text of 259 articles, in 35 abstracts, and in the title of four papers. Studies that included forbs were mostly conducted in mesic or semi-arid grassland or savannas. Articles in which forbs were just mentioned or their abundance measured as a group predominated, but quantitative studies of forb species composition and diversity accelerated during the later decades. Grazing has been the primary impact studied on forbs followed by fire and the environment. Major research gaps identified include the inconsistent grouping or definition of forbs and the lack of data on forb functional or phylogenetic diversity. Overall, this study shows that forb measurement has advanced over six decades, enhancing understanding of grassland responses to grazing and other disturbances, proving the effort to enumerate forbs worthwhile.