Murphy, J.F.; Layer-Dobra, K.; Mathers, K.; Jones, J.I.; Wood, P.J.

Freshwater macroinvertebrate community data, stream discharge, and hyporheic fine sediment mass in experimental channels recovering over a four-month period from a prior drought in 2022

The 3Rs experimental study investigated how trajectories of recovery following a prolonged drought were affected by the prior sediment composition and fine sediment loading. On each of six sampling occasions between December 2022 and March 2023 (Days 1, 8, 13, 29, 57 & 113 following resumption of flow), in each of 12 replicate experimental channels, we collected data on the macroinvertebrate communities on the stream bed surface (benthos), 10cm below the surface of stream bed (hyperheos), and potential colonists dispersing into each of the channels from upstream (drift) and from the aerial insect community (malaise traps). On each occasion we also measured discharge in each of 12 experimental channels as well as the quantity of fine sediment entrained within the stream bed (hyporheic fines).

The dataset being deposited contains the following elements:

• Abundance records for discrete taxa found in samples of the:

o Dry bed sediment - 2.5 kg of bed sediment removed and examined for any macroinvertebrates still persisting in the drying stream bed.

o Re-wetted bed sediment – 2.5 kg of bed sediment removed and retained to identify invertebrates that emerge from the sediments on each sampling day (related article for experimental rehydration of dewatered sediments method description).

o Benthos - Surber sample (330 µm mesh size) of 0.0225m2 area for 30 seconds. A Surber taken from upstream, middle and downstream thirds of the channel length on each occasion.

o Hyperheos - 500ml of water extracted using 60ml syringe from standpipes set 10cm below stream bed surface. A sample taken from upstream, middle and downstream thirds of the channel length on each occasion.

o Drift - Nets (330 µm mesh size) deployed for 24hrs at upstream end of each channel.

o Aerial communities – Malaise traps deployed bankside for 5 days.

• Stream discharge (m3s-1)– stream velocity measured with Valeport 801 Electromagnetic Flowmeter.

• Mass of hyporheic fine sediment (gl-1) – dry mass of fine sediment extracted with the 500ml hyporheic sample.

The work was supported by the Natural Environment Research Council (NE/X016706/1).

Publication date: 2024-03-07