Maintenance of wetland plant communities: the role of the seed bank in regeneration of native plants

Abstract

Exotic grasses have been introduced into wetlands and can compete with native plants due to their high tolerance of flood and dry periods. Flooding can facilitate seed dispersal of exotic species and reduce the diversity of native species. We compared two grasslands to assess whether seed banks can maintain the diversity of native plants in wetlands with introduced exotic plants. We recorded a total of 136 species and a predominance of annual plants in the seed bank and vegetation together. The seed bank had high species diversity independently of the dominance of the exotic Urochloa humidicola in the vegetation. The seed banks of the native and cultivated grasslands differed significantly with a positive correlation for aquatic plants in the native grassland and negative correlation in the cultivated grassland. The seed bank revealed potential to maintain the diversity of native species in the cultivated grassland since the flood and dry seasons promoted the presence of distinct species in the seed bank, but lower richness in the vegetation reflects a dependence on the germination stage. The seasonality of flood and dry periods influences distinct growth forms, increasing the diversity of the seed bank and the vegetation.

Do neighbours matter? The effect of single‐ and mixed‐species sowing density on seed germination of annual wetland plants

“…As all species in this study coexist in the field (Bao et al, 2015) and have high germination percentages in seed bank experiments (Bao et al, 2014, 2018a; 2021; Oliveira et al, 2015; Souza et al, 2016), we expected: (a) a high percentage of germination regardless of the type of competition (intraspecific and interspecific) and seed density; however, it is expected that some species will show variation in germination time depending on the type of competition and the intensity of neighbouring interactions; therefore, (b) germination times would be similar under intraspecific competition, regardless of seed density; and (c) germination time would differ among species when exposed to intraspecific seed competition depending on seed density, with some species having shorter germination times at high seed densities. This group of species may also have a priority effect on germination, refering to the time of species arrival.…”

“…During the dry season, the water recedes and the temporary ponds dry, allowing different topographic levels of seed capture (Bao et al, 2014), which lead to an explosion of germination in annual plant species (Bao et al, 2018b), essential to regeneration and the maintenance of diversity in wetlands after flood disturbance (Souza et al, 2021). Based on previous observations of rapid germination from seed banks with high seed densities followed by high mortality, we were interested in the effect of different types of neighbours on seed germination time (Bao et al, 2014(Bao et al, , 2018a(Bao et al, , 2021. We aimed to group seeds of ten annual species that coexist in the Brazilian Pantanal to determine whether the timing and magnitude of seed germination is density-dependent and can be influenced by intraspecific and interspecific competition.…”

Seed Viability, Spikelet Dispersal, Seed Banks and Seed Storage Requirements for Native and Invasive Cordgrasses (Genus Spartina) in Southwest Iberian Peninsula

“…Soil seed banks play an important role in the establishment, maintenance, regeneration and restoration of vegetation in many plant communities (Bao et al 2021;An et al 2022). In salt marshes, seed dispersal and soil seed banks play an important role in determining the spatial and temporal distribution of halophytes (Egan and Ungar 2000;Rand 2000;Crain et al 2008), and the successional assembly of halophytic communities following disturbance or restoration actions (Dausse et al 2007;Kottler and Gedan 2019).…”