Supplementary information files for Monthly sampling reveals seasonal fine sediment fluctuations and riverine invertebrate community responses

<p dir="ltr">Supplementary files for article Monthly sampling reveals seasonal fine sediment fluctuations and riverine invertebrate community responses</p><p dir="ltr">Managing the impacts of anthropogenically enhanced deposited fine sediment levels in <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/lotic-ecosystem" target="_blank">lotic ecosystems</a> requires understanding of how catchment land-use changes have altered the natural sediment regime (erosion, transport, deposition) of rivers. Unfortunately, no existing studies have employed an appropriate sampling frequency over a period encompassing the full range of seasonal flow conditions expected to influence in-stream sediment dynamics. We determined the short-term (monthly) dynamics of deposited fine sediment and invertebrate communities over 12-months in 15 fourth- and fifth-order rivers draining catchments of low, medium and high land-use intensity in Southland, New Zealand to determine when and where fine sediment threatens stream health. We compared the Quorer <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/resuspension" target="_blank">resuspension</a> method (suspendable inorganic sediment, SIS) and the in-stream visual sediment cover assessment method, and evaluated the effectiveness of four commonly-used invertebrate stream health metrics against their newly developed sediment-specific counterparts. Monthly variability in SIS was substantial across all land-use categories, but became more pronounced as land-use intensity increased. All 15 sites experienced a prolonged period of relatively stable flow which coincided with the largest short-term increase in SIS at 14 of the 15 sites. However, variability in SIS was not mirrored in <a href="https://www.sciencedirect.com/topics/earth-and-planetary-sciences/macroinvertebrate" target="_blank">macroinvertebrate</a> metrics. These findings suggest that controlling inputs of fine sediment to rivers and streams will be most effective when targeted at periods of prolonged stable flow, particularly within high land-use intensity catchments. The resuspension method consistently outperformed visual estimates when considering its relationship with macroinvertebrate metrics, while sediment-specific metrics demonstrated a stronger association with fine sediment than commonly employed metrics e.g. (%EPT). We conclude that restoration/mitigation practices cannot be based solely on short-term, or even long-term, reductions in fine sediment, or on physical measures alone, but should be based on long-term recoveries of sediment-impacted invertebrate communities using concurrent measurements of both biotic and abiotic conditions.</p>