The research was undertaken at a sand dune system located along the South East coast of England, known as Sandwich Bay. Sandwich Bay has attracted a number of environmental designations, including Special Areas of Conservation and a Site of Special Scientific Interest due to the presence of rare habitats and flora found predominantly at this single site, such as Himantoglossum hircinum (lizard orchid) and Orobanche caryophyllacea (bedstraw broomrape). The research focus centred on concerns surrounding ecological change resulting in the loss of grey dunes, an Annex 1 priority feature. Sandwich Bay has been classed as a Special Site of Scientific Interest in unfavourable condition (Natural England, 2014), based primarily upon the loss of fixed grey dune habitats to neutral grasslands (SD8 to MG1/MG12 NVC classifications). The aim was to identify causative factors that might account for the observed historic and any current changes in vegetation. The research was conducted between October 2011 and September 2014, and focused upon hydro-chemical interactions in the environment. Analysis was undertaken by the installation of 103 dipwells across the 520 ha site, in order to obtain groundwater samples. The hydro-chemical and botanical analysis indicated that the vegetation composition was not affected significantly by the chemical constituents within the groundwater. However vegetation composition was significantly modified by variable surface elevation and the related height of the water table. An additional investigation focused upon the identification of management techniques that are thought to be beneficial to dune vegetation restoration. Three management trials were located at three different sites, investigating four different management treatments. Analysis showed that there was a significant difference between the various management treatments and species composition. Vegetation analysis indicated that both cut and remove, and burning, as management treatments encouraged a greater diversity of species, particularly in sheltered eutrophic areas.

Suaeda maritima is an annual halophyte commonly found in salt-marshes. Its salt tolerance has been well studied, though there is little published on the effect of simultaneous waterlogging. The effects of saline waterlogging on growth, antioxidants (glutathione and total polyphenolic compounds, antioxidant activity) and oxidative damage were investigated with simulated tides in a controlled glasshouse and on plants collected from the field. Flooded shoots possessed higher levels of antioxidants than those from plants growing in well-drained situations, in the glasshouse and the field. The effects of hypoxia, (simulated in nutrient solution by flushing with nitrogen in a solution containing a low concentration of agar, which limits convection within the solution and so the transport of oxygen from the air) were determined on growth and trace metal concentrations, in plants grown in different concentrations of artificial seawater (100 and 350 mM Na+ at low pH, > pH 5.5), in sand/mud irrigated with halfstrength fresh seawater (at high pH, ca 7-8) and in different concentrations of manganese and iron in solution culture. High salt concentration reduced accumulation of trace metals in plants. Optimal growth occurred in 14 μM Fe and 1 mM Mn. Accumulation of trace metals was reduced at high pH, with more accumulating in the roots than the shoots. Hypoxia increased soluble sugars in shoots and roots, and this was affected by the salt concentration. Hypoxia also caused adventitious root development in hydroponic experiments, while in sand, adventitious root development was greater in drained than flooded conditions. Hypoxia significantly reduced shoot sodium concentration, sodium flux and bypass flow, at low and high salt concentrations. In high salt conditions, S. maritima reduced its transpiration rate and improved its water use efficiency. It was also shown that the roots contained high lactate concentrations under aerated and hypoxic conditions. S. maritima demonstrated many adaptations for tolerating extreme hypoxia.

The aquatic macrophyte Crassula helmsii is a non-native species and classed as 'invasive' in the UK. This study was carried out in an attempt to provide empirical evidence as to whether the establishment and growth of Crassula helmsii has a measurable impact on the ecology of invaded sites. Dispersal and distribution patterns across England were explored using databases and GIS interpretation. Ecological impact was measured by comparing invaded sites with uninvaded control sites on a range of habitats and waterbody types across Kent and East Sussex. The analysis of spread patterns provided evidence that the plant is likely to have been dispersed due to the horticultural trade, as well as natural vectors into neighbouring habitats. Macrophyte analysis showed that species losses did not occur when C. helmsii was present. Changes to species composition did occur, with rarer plant species being associated with the presence of C. helmsii. Freshwater macroinvertebrates showed no change in either species number or species rarity. The seed banks of invaded and control sites showed no difference, but active management was shown to reduce the total number of seeds in the soil significantly. The water chemistry of invaded and uninvaded sites showed a relationship between the presence of C. helmsii and reduced total organic nitrogen. The results of this study show that the expected species loss associated with non-native species may not be occurring with C. helmsii. Active management may be impacting the ability of native species to recolonise. Further work on other habitats and waterbodies across a wider geographic range are required to explore whether this is a localised effect.