Plant evenness improves forage mineral content in semi-natural grasslands

Abstract

Compared to intensive grasslands, semi-natural grasslands host species-rich and functionally diversified plant communities, and thus represent habitats of high conservation interest. Less is known about their ability to provide high-quality forage fitting livestock requirements regarding mineral content in particular, and thus contribute to livestock health. We address this question by measuring forage macro- and micro-mineral content across a range of semi-natural grassland types in nine locations in France and compare it to standards required for cattle health. We also developed a multi-criteria method using forage mineral concentrations and their recommended ranges to determine general mineral concentration quality (MinQ) in forage. We investigated if forage mineral content and MinQ was related to plant community composition, soil characteristics, and land-use intensity of semi-natural grassland forages. Good forage quality in terms of mineral content was found, matching the reference values, in the majority of the extensively managed semi-natural grasslands studied. Plant species evenness was positively correlated with MinQ. The forage mineral quality varied depending on the community weighted mean of the specific leaf area (SLA_CWM) and the leaf dry matter content (LDMC_CWM). It increased with increasing SLA_CWM and decreased with increasing LDMC_CWM. The results demonstrate that a good compatibility between plant evenness and forage mineral quality can be obtained in semi-natural grasslands which suggests that the continued management of these habitats can offer agronomic services as well as conservation values.