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(5a) Here we are interested in root foraging precision, which is the optimal ratio of roots inside the patch relative to the roots inside the background soil (P* = rp*/rb*) given by: P?=rp?rb?=��j=1nNpj1+��j=1najhjNpj1+��j=1najhjNbj��j=1nNbj. (5b) Equation (5b) thus represents a simple approximation of foraging precision in plants based on plant nutrient uptake physiology and foraging theory. A key assumption of this model is that plants are nitrogen limited and not limited by other resources, particularly carbon. When plants are carbon limited they may shift allocation away from roots and towards shoot production. [http://en.wikipedia.org/wiki/Diglyceride diglyceride] Additionally, this model assumes that the roots are the sole source of nitrogen uptake. For example, root production may not be as important for nitrogen acquisition in nitrogen-fixing plants or mycorrhizal species. These assumptions can be easily met in controlled manipulative experiments and by choosing appropriate model species, but may not apply to all species and contexts. Literature review: range of foraging traits To estimate the range of behavioural foraging traits in plants and parameterize our model, we broadly searched the literature for estimates of Vmax and Km for nitrate and ammonium and translated the reported Vmax and Km into encounter rates and handling times (Table?1). In February 2011, we searched the ISI Web of Science [http://www.selleckchem.com/products/AZD0530.html AZD0530 research buy] for the topic ��root uptake kinetics�� which returned 870 papers. To make search results more manageable, we filtered the results to the Web of Science Category ��Plant Sciences��. This produced 509 papers. We then inspected titles and abstracts to reduce the search to only papers that reported parameters for nitrate and/or ammonium. From the remaining 219 papers we read [http://www.selleckchem.com/products/GDC-0941.html GDC-0941 in vivo] each manuscript to collect parameter estimates. We limited our data collection to papers that estimated parameters based on either fresh or dry weight of roots and that estimated both Vmax and Km using the Michaelis�CMenten equation. Despite the fact that all plant papers we reviewed used the two-parameter Michaelis�CMenten equation to fit their data, a surprisingly large number of papers only reported Vmax, while failing to report the second parameter, Km. We excluded these papers. Additionally, we limited the data to only plant species with areal shoots so that nutrient capture was achieved exclusively through roots. Fully aquatic plants and algae were therefore excluded, but wetland plants were included. A small number of studies (