The River Thame catchment is home to a number of aquatic and riparian plant species. Below are the most common species which were found in the area in our 2013 surveys:
Creeping bent – Agrostis stolonifera – a hardy grass species found alongside channels.
Wild angelica – Angelica sylvestris – have tall stems punctuated with an umbrella of white flowers.
Fool’s water cress – Apium nodiflorum – short stalked plants with small white flowers.
Tufted hair grass – Deschampsia caespitose – grass species which flower with feathery panicles in the summer.
Water figwort – Scrophularia auriculata – a tall plant, red/brown flowers protrude from the stem.
Woody nightshade – Solanum dulcamara – a vine which can reach up to 4m when growing over other plants. Has purple flowers in summer and produces red berries in the autumn.
Even though there are plants found throughout the Thame catchment, the diversity overall is very low. This is most likely a result of the poor water quality in the river which means that only the most tolerant species can survive. Higher water quality would improve the range of plants seen in our river, which is one of the reasons we are trying to reduce nitrate and phosphate concentrations in the water. Many of the species found in the Thame are invasive – this means they are not native to the area and are causing problems for indigenous species here. If we are successful in reducing pollution in the river, you may see a lot more species of plants appearing across the catchment.
Phytoplankton in Rivers
Phytoplankton are microscopic organisms of which most are unicellular plants. Although singularly undetectable by the naked eye, when grouped on the water surface they may be visible. They are autotrophic – which means they are able to make their own food by using energy from the sun in photosynthesis – rather than having to get food from other sources like heterotrophic zooplankton. Phytoplankton are the base of riverine food webs – they are producers, and are commonly eaten by zooplankton, as well as larger organisms like snails and shrimp. Excess phytoplankton can cause issues in rivers – cyanobacteria commonly form algal blooms which may be result from eutrophication. This can change the pH, oxygen, and light reaching the water which negatively impacts the ecosystem.