Phosphorus availability as the primary determinant of nutrient limitation in temperate biodiverse herbaceous vegetation

Abstract

Understanding whether nitrogen (N), phosphorus (P) or potassium (K) (co)limit productivity across biodiverse herbaceous habitats is crucial to guide management. Therefore, we investigated for 386 plots representing 13 nutrient-limited habitat types across Europe whether community N:P:K stoichiometry and limitation types differ along wide-ranging gradients in soil development, moisture and pH. Results indicate P/P+N as frequent as N limitation. K/K+N limitation occurs not where K availability is minimal, but in species-impoverished habitats with excess N and P. Overall, P emerges as primary driver of stoichiometry, strongly driven by the environment: at optimal pH of 6, N:P and P/P+N limitation are minimal and N limitation maximal, despite also good conditions for N availability. At pH7, N:P is high and P/P+N limitation common. Our findings emphasize soil pH control on nutrient limitation through influence on P. Studies reporting widespread K (co)limitation in temperate herbaceous vegetation likely sampled anthropogenically P/N-enriched communities.