Abstract Detail


Watts, Jacob [1], Pellegrini, Adam [2].

Investigating the Root Economic Spectrum hypothesis and plant-fire dynamics using a macroevolutionary common garden.

Prairies, grasslands, and forests cover an expansive portion of the world’s surface and contribute significantly to Earth’s carbon cycle. The largest driver of carbon dynamics in some of these ecosystems is fire. As the global climate changes, most fire-dominated ecosystems will experience increased fire frequency and intensity, leading to increased carbon flux into the atmosphere and soil nutrient depletion. The plant communities associated with different fire regimes are important for reassimilation of carbon lost during fire and soil recovery. More frequent fires promote conservative plant functional traits aboveground; however, belowground fine root traits are poorly explored and arguably more important drivers of ecosystem function as the primary interface between the soil and plant. The root economic spectrum (RES) hypothesis describes predictable covariation between important fine-root traits along a range of plant strategies from acquisitive to conservative just as the well-established leaf economic spectrum (LES). However, because of the paucity of root trait data available, the complex nature of the rhizosphere, and the phylogenetic conservatism of root traits, it is unknown whether the RES hypothesis accurately describes plant nutrient and water acquisition strategies. This project utilises the rich plant diversity grown in common garden conditions found in the Cambridge University Botanic Garden and metaanalysis techniques to examine the belowground physiological traits of 50 herbaceous species to 1) test the RES hypothesis, 2) describe the evolution of root traits over long evolutionary time scales, and 3) elucidate the effect of fire regimes on fine root functional traits - which in turn affect carbon and nutrient cycling. I measured morphological, chemical, and biological root traits and fit multivariate evolutionary models. Preliminary results show little support for a strong, unidimensional RES and suggest strong phylogenetic conservatism of traits among species. Additionally, conservative traits are often associated with fire-tolerant species, which may be indicative of slower carbon cycling with increasing fire frequency and intensity.

1 - University of Cambridge, Plant Sciences, Churchill College, Storeys Way, Cambridge, CB3 0DS, UK
2 - University of Cambridge, Plant Sciences, Newnham College, Sidgwick Ave, Cambridge, CB3 9DF, UK

fine roots
common garden
disturbance ecology
economic spectrum.

Presentation Type: Oral Paper
Number: MACRO I001
Abstract ID:115
Candidate for Awards:None

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