The importance of being reliable – Local ecological knowledge and management of forage plants in a dryland pastoral system (Morocco)

• Ecological apparency hypothesis EAH predicts which plants are most valued by humans.
• We tested the validity of EAH for forage plants in a dryland pastoral system.
• Apparent plants from semi-arid pastures were more valued than those from arid ones.
• Plants' reliability on semi-arid pastures could explain their higher valuation.
• Pastoral mobility is adjusted to the reliability of forage plants on pasture types.

In dryland rangelands with their high environmental variability, local ecological knowledge of forage plants is essential for management decisions. Ecological apparency hypothesis (EAH) predicts plants' availability and visibility to be important criteria for local valuation. However, EAH has mainly been tested in low-variability systems. We ask whether EAH is valid for forage plants in drylands; which other local criteria exist; and how criteria are connected to management decisions.In a Moroccan pastoral system, we applied a novel ethnobotanical method by calculating the Cognitive Salience Index (CSI) for plants' valuation (CSIantro) and availability (CSIeco). To evaluate explicit criteria, we correlated palatability and nutritive value to CSIanthro. ANCOVAs related CSIanthro to EAH criteria (CSIeco and lifetime) and to plant occurrence on pasture types. We found EAH criteria to better predict CSIantro than explicit criteria. Apparent plants from semi-arid pastures were more valued than those from arid pastures (HSD; p < 0.05). We introduce the criterion of reliability into EAH to explain this, and demonstrate how pastoralists adjust management decisions to resource reliability. Linking resource valuation to management decisions can thus improve our understanding of resilience mechanisms. Our study also confirms the validity of EAH for forage species and dryland environments.