Abstract:
Fine roots are complex and complicated organs to study. The logistic difficulties to access them and a poor understanding of relationships between form and function have left below‐ground plant organs largely oversimplified or ignored in most ecological studies. Fortunately, since the seminal work of Pregitzer et al. (2002), there have been an increasing number of ecologists focused on quantifying and understanding the functional role of living roots in terrestrial ecosystems. The field of root ecology has progressed from the traditional view of roots as passive organs in charge of anchorage and nutrient absorption to the view that roots have a more dynamic role as drivers of soil organic carbon (Rasse, Rumpel & Dignac 2005), nutrient cycling (Phillips et al. 2012) and the composition and productivity of plant communities (Bardgett, Mommer & de Vries 2014; Valverde‐Barrantes et al. 2015). In addition, an increasing effort to link above‐ and below‐ground organs within individuals (Withington et al. 2006) and across species (Holdaway et al. 2011) is providing us with more realistic information to scale plant function from communities to biomes, improving our capacity to understand global biogeography and biogeochemical cycles. An excellent example of the importance of this integrative perspective comes from Kramer‐Walter et al. (2016) in this issue of Journal of Ecology. Kramer‐Walter et al. (2016) compare leaf, stem and root functional traits of 66 of the most common native woody species in New Zealand. By measuring traits under controlled conditions and then relating community‐level traits to environmental gradients, they addressed two pivotal questions in plant ecology: (i) Is there evidence of a root economic spectrum (RES) among root traits and is it coupled to a broader plant economic spectrum (PES)? and (ii) How do traits and/or the integrated plant economic spectrum reflect plant adaptations to their natural habitats, particularly with respect to soil fertility? Their results revealed higher complexity in the integration of functional traits in roots with respect to leaf trait integration. Moreover, Kramer‐Walter et al. (2016) showed that although part of the variation in root traits, along with leaf and stem traits, corresponds with environmental gradients, there are potential additional factors driving trait variation below‐ground that has not been properly quantified in root ecology.
The rest of the article can be found here: https://doi.org/10.1111/1365-2745.12605