2.3.1. Qualitative Analysis

To determine the effects of the treatments simulating a future climate within the studies included in our review, we looked for the direction and significance level from statistical analyses reported in each study and we recorded them in a database as a positive, negative or neutral effect. Then, we categorized the extracted observations according to the focused life stage and the climate change scenario to which they were subjected. With the extracted data, we constructed bar and pie charts.

In order to categorize and analyze the studies according to the life stage in which they focused, we defined the following life stages: (1) seed maturation, when fruits or seeds are still attached to adult plant; (2) seed dormancy, when fruits or seeds have been dispersed or collected from the adult plant but before ambient conditions meet the requirements for germination and during the time seeds are part of the soil seed bank; (3) seed germination, when ambient conditions meet the requirements for germination (radicle emerge from seed); (4) seedling emergence, when cotyledons open or emerge from the ground; (5) seedling establishment, after seedlings have emerged up until the end of the study and including all reported measurements of seedling survival, mortality or establishment.

While extracting the data for the qualitative analysis, we used the following criteria: (a) when the studies reported a single control and several treatments (e.g., temperature: control, +5 °C, +10 °C, +15 °C, and +20 °C), we recorded the results of the control and the treatment that best fits the climate change projections cited by the authors; and (b) when studies tested seeds from different provenances, we specifically recorded information for those seeds collected from either treeline, tundra, alpine or subalpine ecosystems (Database S1).