Joanne Goodson

Riparian seed banks: structure, process and implications for riparian management

After a brief description of the evolution of seed bank research, this review highlights the importance of the seed bank in understanding the character and dynamics of river margins. Through a discussion of published research on wetlands in general, the lack of research focused on riparian systems is highlighted. This is followed by an evaluation of current knowledge concerning the nature and dynamics of riparian seed banks and the factors that control the erosion, transport and deposition of riparian seeds. The paper concludes by (i) indicating the complexity of the interactions that control the riparian seed bank and that require understanding if the consequences of alterations in river flow regime and riparian management are to be fully understood and (ii) identifying some major research gaps relating to interactions between fluvial processes and riparian seed banks.

Riparian seed banks along the lower River Dove, UK: their structure and ecological implications

This paper investigates associations between the viable seed bank, sediment properties and elevation on three eroding river banks along the lower reaches of the River Dove, Derbyshire, UK. Using both descriptive statistics and detrended correspondence analysis, major contrasts are found in the abundance and floristic composition of the viable seed bank between the bank top, bank face and bank toe and between the three study sites. Canonical correspondence analysis identifies associations between the floristic composition of the seed bank and the percent organic matter, percent clay, percent sand and median particle size of the soil matrix that contains the seeds. The patterns revealed by the above analyses indicate (i) an increasing influence of fluvial processes (hydrochory) on the species composition of the seed bank with decreasing elevation; (ii) a low abundance of viable seeds on unvegetated eroding bank sections, suggesting limited long-term storage of viable seeds within floodplain sediments; and (iii) a very substantial seed bank where old channel sections provide a local depositional environment. The implications of these observations for understanding the role of fluvial processes in riparian seed bank dynamics and their implications for riparian management are discussed.

Three seedling emergence methods in soil seed bank studies: implications for interpretation of propagule deposition in riparian zones

Samples of soil and recently deposited sediments were collected from the river bed, bank face and bank tops of two lengths (reaches) of the River Frome, Dorset, UK and one reach of the River Tern, Shropshire, UK. Soil propagule bank samples were collected in May 2003, and depositional samples were collected subsequently over four consecutive 4-month periods between June 2003 and October 2004. The samples were subjected to three emergence trials under drained, waterlogged and submerged conditions. Significantly more seedlings germinated in the drained than waterlogged trial, and waterlogged than submerged trials. Drained, waterlogged and submerged trials identified 186, 76 and 37 species, respectively. Six species identified in the waterlogged trials were not identified in the drained trials, and five species in the submerged trials were not found in the drained trials. Submerged trials added two species to the drained and waterlogged results. Application of detrended correspondence analysis (DCA) to average species abundance data, for the sampled hydrological habitats (bed, bank face, bank top) within the soil propagule bank and four depositional data sets, generated different results for the three trials. The drained treatment revealed significant differences between sites, seasons and hydrological habitats, whereas the waterlogged and submerged treatments presented an increasingly homogeneous view of the samples. Our results confirm other propagule bank emergence comparisons and extend them to depositional samples, demonstrating that the strong environmental sieves imposed by waterlogging and submergence restrict emergence of numerous terrestrial, wetland and even some aquatic species that were successfully identified using the drained conditions.