Diverse belowground resource strategies underlie plant species coexistence and spatial distribution in three grasslands along a precipitation gradient

• Published in: The New phytologist Vol. 216; no. 4; pp. 1140 - 1150
• Main Authors: Li, Hongbo, Liu, Bitao, McCormack, M. Luke, Ma, Zeqing, Guo, Dali
• Format: Journal Article
• Language: English
• Published: England New Phytologist Trust 01.12.2017; Wiley Subscription Services, Inc
• Subjects: Abundance; adaptive strategy; Branching; Capacity; China; Climate change; Coexistence; Colonization; Distribution; Fitness; Flowers & plants; foraging strategy; Grassland; Grasslands; Herbivores; Length; Magnoliopsida - anatomy & histology; Magnoliopsida - microbiology; Mycorrhizae; mycorrhizal colonization; Plant communities; Plant populations; Plant Roots - anatomy & histology; Plant Roots - microbiology; Precipitation; Rain; Rainfall; root branching; Roots; Spatial distribution; Species; species distribution; Survival; temperate steppe; trade‐off; trait variation; Variation; species distribution; root branching; mycorrhizal colonization; trade-off; temperate steppe; adaptive strategy; foraging strategy; trait variation
• ISSN: 0028-646X; 1469-8137
• DOI: 10.1111/nph.14710

Functional traits and their variation mediate plant species coexistence and spatial distribution. Yet, how patterns of variation in belowground traits influence resource acquisition across species and plant communities remains obscure. To characterize diverse belowground strategies in relation to species coexistence and abundance, we assessed four key belowground traits – root diameter, root branching intensity, first-order root length and mycorrhizal colonization – in 27 coexisting species from three grassland communities along a precipitation gradient. Species with thinner roots had higher root branching intensity, but shorter first-order root length and consistently low mycorrhizal colonization, whereas species with thicker roots enhanced their capacity for resource acquisition by producing longer first-order roots and maintaining high mycorrhizal colonization. Plant species observed across multiple sites consistently decreased root branching and/or mycorrhizal colonization, but increased lateral root length with decreasing precipitation. Additionally, the degree of intraspecific trait variation was positively correlated with species abundance across the gradient, indicating that high intraspecific trait variation belowground may facilitate greater fitness and chances of survival across multiple habitats. These results suggest that a small set of critical belowground traits can effectively define diverse resource acquisition strategies in different environments and may forecast species survival and range shifts under climate change.