In order to be able to interpret and effectively respond to ecosystem variability and change, wild flora and fauna were also used as indicators. Farmers observed the development of wild plants and the development and behavior of wild animals, and used this information to plan and adjust land management. For example in Roslagen, Sweden, the size of birch leaves can give an indication of when to sow. The presence of certain plant species gives an indication on soil quality.
Being in an environment where natural habitat co-exists with the agro-ecosystem and is protected enables the use of natural indicators.
In variable conditions, the timing of planting and harvesting is critical. Natural indicators capture multiple information that is important for crop success or at least reducing failure.