Bromus tectorum litter alters photosynthetic characteristics of biological soil crusts from a semiarid shrubland

► Responses to plant litter cover were investigated in two biological soil crusts. ► Litter cover induced changes in respiration and photosynthetic parameters. ► The photosynthetic capacity was lower in litter treated than control crusts. ► Negative effects of the litter were more marked in a moss than in a lichen crust. ► The results explain changes in crust cover and composition with increases in litter.