Effects of flooding on germination and establishment of the invasive cordgrass Spartina densiflora

Abbas AM, Rubio‐Casal AE, De Cires A, Figueroa ME, Lambert AM & Castillo JM (2012). Effects of flooding on germination and establishment of the invasive cordgrass Spartina densiflora. Weed Research52, 269–276. Summary Flooding has been described as one of the most important environmental factors determining the distribution of salt marsh plants. We studied the impact of five water levels (from well‐drained to 8 cm deep) on the germination and establishment of the invasive cordgrass Spartina densiflora under controlled glasshouse conditions. The germination rate was ca. 60%, tending to decrease gradually with depth. There was no seedling emergence from deeper than 4 cm, because every seedling at 8 cm died. Spartina densiflora showed a high physiological plasticity. Seven months after germination, relative water content varied between 69 ± 13% at well‐drained conditions and 87 ± 7% at 4 cm, without significant differences between treatments. Plants rooted at 4 cm presented the highest quantum efficiency of photosystem II (PSII) with slightly lower maximum net photosynthesis rate than other treatments, reflecting high photoprotection levels, together with low nitrogen and pigments contents. Water level depth reduced shoot relative growth rate (RGR). Our results could be useful to fight S. densiflora invasion, because artificial inundation of invaded marshes to a water depth of 8 cm would prevent its establishment from the seed bank.