Allocating CSR plant functional types: the use of leaf economics and size traits to classify woody and herbaceous vascular plants

Abstract

Summary1. Three main directions of adaptive specialization are evident in the world flora, reflecting fundamental trade-offs between economics (conservative vs. acquisitive investment of resources) and size. The current method of ordinating plants according to these trade-offs, CSR classification, cannot be applied to the woody species that dominate many terrestrial ecosystems. 2. We aimed to produce a novel CSR classification method applicable to vascular plants in general.3. Principal components analysis (PCA) of variation in a range of plant traits for 678 angiosperm, gymnosperm and pteridophyte species was used to determine the limits to multivariate space occupied by functionally diverse species. From this calibration, correlations between PCA axes and values of leaf dry matter content (LDMC; as an index of conservatism in life history), specific leaf area (SLA; indicative of acquisitive economics) and leaf area (LA; photosynthetic organ size) were used to produce predictor regressions from which target species could be compared against the multivariate space. A spreadsheet was developed that returned ternary coordinates and tertiary CSR strategies for target subjects based on LA, LDMC and SLA values. 4. The method allowed classification of target species within a triangular space corresponding to Grime's theoretical CSR triangle and was sufficiently precise to distinguish strategies between species within genera and within populations of species. It was also largely in agreement with previous methods of CSR classification for herbaceous species. 5. Rapid CSR classification of woody and herbaceous vascular plants is now possible, potentially allowing primary plant functional types and ecosystem processes to be investigated over landscape scales.

The global spectrum of plant form and function

“…The positions signalled by numbers 3, 4, and 5 in Fig. 2a (and described in Extended Data Table 2) could arguably roughly correspond to the stress-tolerant, ruderal, and competitor strategies of Grime 3,11,19 . Interestingly, the functional hotspots lie at intermediate positions on the plane rather than at any of these extreme positions (that is, r versus K, acquisitive versus conservative resource economy, C, S or R-strategy).…”

The intimacy between sexual traits and Grime’s CSR strategies for orchids coexisting in semi-natural calcareous grassland at the Olive Lawn

“…Apart from leaf size, 'economics' traits form a major axis of variability in vascular plant phenotypes globally known as the 'worldwide leaf economics spectrum' (Wright et al 2004). This spectrum reflects a gradient of acquisitive to conservative resource investment strategies evident in resource-rich to resource-poor habitats, and consistently emerges in multivariate analyses of plant traits (Díaz et al 2004;Cerabolini et al 2010;Frenette-Dussault et al 2012;Freschet et al 2012;Pierce et al 2013). At the 'acquisitive' end of this spectrum are leaves with high specific leaf area (i.e.…”

“…Primary strategies are essentially suites of traits that impact on key functions allowing survival, and involve the investment of photosynthates and mineral nutrients in three principal activities: further growth, the maintenance and protection of metabolic processes, or reproduction (Grime and Pierce 2012). Strategies thus represent a three-way investment trade-off between traits facilitating these competing functions: a trade-off that has been recorded repeatedly in large scale studies of wild plants (Díaz et al 2004;Cerabolini et al 2010;Frenette-Dussault et al 2012;Pierce et al 2013). These three principal extremes of adaptive specialization are predicted by Grime's (2001) competitor, stress-tolerator, ruderal (CSR) plant strategy theory and its successor, universal adaptive strategy theory (Grime and Pierce 2012), in which C-selected 'competitors' maximize growth by using large physical size (large leaves and root systems, tall canopies) to acquire resources and dominate stable, resource-rich niches.…”

“…The R-and S-selected extremes have been shown to be correlated directly with 'acquisitive' and 'conservative' leaf economics trait values, and large-leaved competitors are evident only at the mid-point of the leaf economics spectrum (Cerabolini et al 2010). Thus a CSR classification method has recently been produced that uses a combination of leaf economics and leaf area measurements to assign species a precise position within the CSR triangle (Pierce et al 2013). …”

Competitive, stress-tolerant and ruderal based classification of some plant species in an Alpine community of the Giresun Mountains in Turkey

“…Recent studies have shown ambiguous results in relation to apply the CSR model, especially to woody species (Pierce et al, 2013). Navas et al (2010) used revised categories for lateral spread proposed by Grime et al, (2007) to modify CSR classification and include woody species.…”