Assessing nutrient impacts on lakes from birds

When looking at the various nutrient inputs to lakes, bird faeces are often cited as a conspicuous source of nutrients, and a potential reason for not reaching favourable condition on SSSIs lakes that are designated for their lake-habitat interest. We don't currently know the nutrient loads from birds at SSSI lakes or how significant a source of nutrients this is.

This project aims to produce a tool to calculate the nutrient inputs to SSSI lakes from birds. The aim is to be able to use WEBS and other available bird data, in conjunction with known concentrations of nutrients in faeces from different bird species (the contractor will need to find this information from the literature), to calculate nutrient (Total N & P) loads in kg/ha from birds for all the lake-habitat SSSIs (a list of these will be supplied). The relative importance of the nutrient contribution from the birds at each site also needs to be understood.

As many SSSI lakes are currently not reaching their nutrient targets this needs to be understood from two perspectives.

1. The proportion of the current total nutrient load, which is calculated as coming from the current bird populations

2. The proportion of the total nutrient load, which would be low enough for the lakes to reach their nutrient targets, which is calculated as coming from the current bird populations.

The Outputs from the project will be:

• Outputs calculated for 161 individual SSSI lakes designated for lake habitat (subject to bird data being available from WEBS or other data sources). This can be presented as an excel tool populated with individual lake parameters and outputs. In which case there should be an excel output for each lake.

• A report explaining the methodology used to calculate the nutrient contributions, a guide to using the tool and main findings about the contribution of birds to lake nutrient concentration in English SSSIs.

• The tool must be designed so that it can be easily updated with new data on bird species and abundance utilising a particular (SSSI) lake.

• The priority application for this tool is to determine impact on SSSI lakes. However, it should be designed so that it could be easily used for other non-designated site lakes (subject to supporting data being available)

• The tool should be able to run independently on a laptop, using standard Microsoft products (ideally Excel) so it can be easily used and shared across Natural England and with other colleagues.

• The user-interface should be easy to use, with a simple guide to accompany the tool.

• One recorded teams call where the tool will be demonstrated, so it can be used as a future training resource. Please see the full RFQ and specification for further information.

Additional information: Quotations are requested to provide information required in the RFQ. The timeline given in the RFQ will be followed to enable the project to be delivered by end of March 2023.