Chapter 11 illustrates different strategies to obtain reliable and robust trait data from both field sampling and experiments. An exercise is provided to familiarize readers with different alternatives for sampling traits, and their implications for sampling effort, providing advice on defining a realistic trait sampling campaign. Examples show that a feasible sampling strategy needs to sacrifice aspects of trait variability of lower importance for the ecological questions being asked and how researchers should attempt to compromise between the most accurate and most precise estimations of trait values. Special attention is given to the expected effect of species turnover vs intraspecific trait variability adjustments across gradients, depending on the extent of the studied environmental gradient. The choice of a given sampling scheme is framed into simple trade-offs between two extreme cases: sampling several individuals for each species from only a single population, or sampling one individual per species in each population in which the species occur along a gradient. A flowchart guide for choosing among different sampling combinations along this trade-off is provided.

Chapter 2 provides general answers to some of the most frequently asked questions by researchers and practitioners aiming to apply trait-based methods: How to select the right trait(s) and how many traits should be selected? Where to find reliable trait values? Are the trait values provided in the literature or databases appropriate, and sufficient, for a given study system, or should traits be measured in the field? The need for standardization in trait measurements is discussed, particularly in terms of the importance of building reliable and useful trait databases. Different types of traits (quantitative, categorical, circular etc.) are introduced, as multiple types of traits are often needed to answer most ecological questions. A list is provided of existing trait databases from which trait information for different taxonomic groups can be obtained. The R material accompanying the book provides tools to extract trait data from some of these databases and combine it with other available species and community data.