Forage Provision Dynamics in Drylands: A Non‐Destructive Estimation Based on Grass Populations

ABSTRACT

Drylands worldwide are predominantly used for animal husbandry and provide critical ecosystem services such as forage provision and carbon sequestration. Sustainable livestock grazing management in these ecosystems relies on accurate forage dynamics assessments. Forage dynamics largely result from the characteristics of the plant populations composing the community, the traits of domestic herbivores and the management strategies that influence consumption and selectivity. However, traditional forage evaluations often focus on total productivity, plant cover or biomass measurements, overlooking plant‐size population structures that control forage dynamics as perceived by grazers. We developed species‐specific allometric equations for dominant perennial grasses of the Patagonian steppes to estimate aboveground biomass categories related to the provision of forage and other ecosystem services—including total, green, senescent, standing‐dead and crown biomass—based on plant size. Then, we applied the equations to assess the effects of sheep grazing intensity on population plant‐biomass structures and forage biomass in commercial‐sized paddocks. The non‐destructive allometric method was highly accurate ( R ² ranged 0.77–0.90; p  < 0.001 for green and total biomass models), allowing efficient biomass estimations across different plant morphologies under varying grazing pressures. Notably, grazing intensification did not affect total grass green biomass, but significantly reduced forage biomass by 70% ( p  < 0.001) due to the substantial population decline in sheep‐preferred species, highlighting the differential impacts of selective grazing on specific biomass components. By enabling a finer understanding of plant–animal interactions and species‐specific biomass dynamics, our method supports informed management strategies to sustain critical ecosystem services in Patagonian steppes and other drylands grazed by selective herbivores.