Effect of biological soil crusts on the germination of three plant species under laboratory conditions

Semiarid grasslands in northeastern Mexico contain many endemic plants and animals and are an important refuge for resident and migratory animals. Here, as in many other semiarid areas, biological soil crusts are a key component of the ecosystem. However, findings about their effect on the germination of vascular plants are in contrast. We asked whether germination of some native plant species would be inhibited by the presence of biological soil crusts as it has been found in other studies and evaluated the effect of seven dominant biological soil crusts: Psora cerebriforme (W.A.Weber), Psora decipiens (Hedwig) Hoffm., Placidium sp., Endocarpom pussillum (Hedwig), Xanthoparmelia chlorochroa (Tuck.) Hale, Nostoc commune (Vauch), and Oxymitra sp. from the area, on the germination percentage and germination rate of three native plant species: Frankenia gypsophila (I.M.Johnst.), Muhlenbergia arenicola (Buckl.), and Sartwellia mexicana (A.Gray). Germination tests were carried out in an environmental chamber at 26 °C and at a constant humidity of 60% with 12 hours by 12 hours light and darkness. Biological soil crusts did not affect germination percentage of the three evaluated plant species when compared to bare soil. Germination rate ranged between 3.5 and 5 days and there were no differences between substrates.