These data are algal production values in eight Welsh upland rivers with contrasting land-use, moorland and exotic conifer, in response to riparian deciduous leaf addition. Eight sampling reaches were chosen at two sites, Llyn Brianne (4 reaches) and Plynlimon (4 reaches). The experiment consisted of adding deciduous leaves to half of the reaches whilst the other half were maintained as a control (no addition of deciduous leaves). In order to characterise the algal production of the studied streams, algal biofilm samples were collected from tiles previously placed, during January 2013 (before deciduous leaf addition) and March 2013 (after deciduous leaf addition) in each sampling reach. The main goal of this survey was to examine how aquatic biodiversity and organic matter stocks respond to deciduous leaf addition in moorland and conifer forested rivers. Dr Isabelle Durance was responsible for organising the surveys, Dr Hugh Feeley, Dr Anne-Laure Sauvadet and Marian Pye were in charge of collecting, processing and sorting the samples. The work was carried out under Diversity in Upland Rivers for Ecosystem Service Sustainability (DURESS) project (Grant reference NERC NE/J014818/1). DURESS was a project funded by the Natural Environment Research Council (NERC) Biodiversity and Ecosystem Service Sustainability (BESS) programme.
Publication date: 2017-03-28
This dataset is part of the following
Each stream was divided into an upstream control zone and a downstream experimental zone. Samples of algal biofilm were collected from tiles previously placed on each sampling site. Deciduous leaves were added directly to the stream and by fixing 'Onion bags' of leaves the stream bed and bank. Algal samples were collected two occasions, January (3-16/01/2013), and March (11-14/03/2013) in all the streams in both the upstream reference zones and downstream experimental zones. Six experimental units (algal tiles) were placed randomly in each reach of the experimental sites before and after the manipulation. Chlorophyll a accrual on tiles was used as a proxy measure of algal production and herbivory rates measured over the sampling periods (after Hladyz et al. 2011). Unglazed ceramic tiles (100 millimetres x 100 millimetres) were glued in pairs to house bricks, which were fixed to the benthos with a rebar stake placed through a hole in the brick centre. The vertical edges of one tile on each brick were coated with a layer of petroleum jelly to deter crawling gazers, and the other tile was left as a control, to assess the strength of grazing pressure. Chlorophyll was extracted using acetone, and the concentration subsequently measured spectrophotometrically (after Layer et al. 2010). Data was entered into an Excel spreadsheet and then exported as a comma separated value file for ingestion into the Environmental Information Data Centre.