DOI: 10.5061/dryad.4f4qrfjf3
title: Interspecific differences in root foraging precision cannot be directly inferred from species' mycorrhizal status or fine root economics

description: Nutrient acquisition in plants can be represented by a suite of
 intercorrelated root traits such as root diameter, nitrogen content, root
 tissue density, and specific root length. However, it is unclear how a
 plant's ability to precisely forage for nutrients in a heterogeneous
 soil environment (i.e., the precision of placing roots into nutrient-rich
 areas) relates to these traits. Mycorrhizal symbiosis also affects the
 relationship between the fine root traits and root foraging precision
 because fungal hyphae may be used for foraging instead of roots.
 Hypotheses matching high root foraging precision with low mycorrhizal
 colonization or "fast" acquisitive strategies of plants have
 been raised based either on data from tree species or a limited number of
 herbaceous species. To test these hypotheses, we compiled data quantifying
 the experimentally measured degree to which root biomass responded to
 patchy substrate nutrient concentrations (i.e., root foraging precision)
 for 123 herbaceous grassland species using a partial meta-analysis. We
 tested root foraging precision relationship with root traits involved in
 nutrient acquisition and mycorrhizal symbiosis (root diameter, specific
 root length, root tissue density, root tissue nitrogen content, and
 mycorrhizal colonization). The root foraging precision data came from four
 different pot experiments, and the trait data were extracted from publicly
 available trait databases. We used a phylogenetically informed approach in
 order to detect the degree of conservation of the relationships. 
 We found that root foraging precision was not significantly correlated
 with other fine root traits and mycorrhizal colonization. Thus, it appears
 unrelated to the main dimensions of the nutrient acquisition space of
 herbaceous species, namely acquisitive-conservative strategy and
 outsourcing of acquisition to the fungi. Also, we found only a very weak
 phylogenetic signal in root foraging precision of 123 species. Our results
 suggest that root foraging precision constitutes another distinct,
 evolutionarily independent dimension in herbaceous species' trait
 space.
description: We collected data about the root foraging
 potential of 123 herbaceous species from four different studies conducted
 between 2010 and 2017 (Belter 2014, Keser et al. 2014, 2015, Weiser et al.
 (2016 + unpublished data)).
 Root
 foraging precision was calculated for each plant separately as <em>log (root biomass in rich
 patch/root biomass in poor patch).</em> Plant root traits were extracted from the
 "Global root traits (GRooT) database" (Guerrero-Ramirez et al. 2021) and from the Alberta grassland plant trait
 database (Cahill 2020). The traits used here were: root diameter (62
 species, [cm]), nitrogen (N) content in roots (60 species, [mg/g]), root
 tissue density (RTD; 66 species, [g/cm³]), and specific root length (SRL; 74 species,
 [m/g]). Specific leaf area (SLA,
 [mm²/mg]) was
 collected from the LEDA Traitbase (Kleyer et al. 2008) for 91 species.  We collected mycorrhizal data from the
 "FungalRoot: Global online database of plant mycorrhizal
 associations" (Soudzilovskaia et al. 2020). We classified species solely noted as
 having arbuscular mycorrhiza (AM) associations as "obligatorily
 mycorrhizal" (55 species), species with both AM and non-mycorrhizal
 (NM) records as "facultatively mycorrhizal" (44 species), and
 species with only NM records as "non-mycorrhizal" (7 species).
 We also extracted data about the intensity of mycorrhizal colonization
 from the same database (60 species).  Belter, P. R. 2014. Relationships among diverse root
 foraging behaviours: understanding plant behavioural types - supporting
 data. - ERA Cahill, J. F. 2020. Alberta grassland plant trait data. -
 ERA Guerrero-Ramirez, N. R. et al. 2021. Global root traits
 (GRooT) database. - Glob. Ecol. Biogeogr. 30:
 25–37. Keser, L. H. et al. 2014. Invasive clonal plant species
 have a greater root-foraging plasticity than non-invasive ones. -
 Oecologia 174: 1055–1064. Keser, L. H. et al. 2015. Herbaceous plant species
 invading natural areas tend to have stronger adaptive root foraging than
 other naturalized species. - Frontiers in Plant Science 6:
 273. 
 Kleyer, M. et al. 2008. The LEDA Traitbase: a database of
 life-history traits of the Northwest European flora. - Journal of Ecology
 96: 1266–1274. Soudzilovskaia, N. A. et al. 2020. FungalRoot: global
 online database of plant mycorrhizal associations. - New Phytol. 227:
 955–966. Weiser, M. et al. 2016. Root Foraging Performance and
 Life-History Traits. - Frontiers in Plant Science 7:
 779.
description: Missing values are marked as "NA".
 The variable names used in the dataset are described at ReadMe
 file. For more details about data processing see
 Materials and Methods section of the paper.