2014 Natural England Humber Estuary SAC Intertidal Sediment Survey.

notPlanned

"The Humber Estuary is one of the largest estuaries in the UK and drains over 20% of the total land surface of England. Major tributaries flowing into the estuary include the Rivers Hull, Trent, Ouse, Wharfe, Aire, and Don. The Humber Estuary Europen Marine Site is comprised of the marine components of the Humber Estuary SAC, SPA and Ramsar site. In 2004 the entire Humber Estuary (37,000Ha) and the associated features of interest were notified as a SSSI. The estuary supports nationally important numbers of wintering waterfowl and passage waders, and a nationally important assemblage of breeding birds in the loland open waters and adjacent margins. Intertidal mudflats and sandflats are one of several interest features of the site. IECS was commissioned by Natural England to conduct an ecological survey in order to monitor and assess the intertidal mudflat and sandflat communities of the Humber Estuary. Natural England identified four survey sectors including the inner, middle, North bank outer and South bank outer estuary. In each of these four sectors, seven Phase II sampling transects were located, positioned in order to ensure all main biotopes had been targeted, and to provide good spatial coverage of the estuary. Due to the spatial extent of the survey area and expanses of deep mud, a hovercraft was used to facilitate the safe movement between transects. Standard NMBAQC and WFD protocols for the collection of benthic core samples and particle saize analysis (PSA) were followed. Two sampling stations were located at mid and low shore along each transect located within the inner and middle estuary sectors. Three sample locations were located along each transect positioned within the outer estuary on both the north and south banks. These sampling positions covered the upper, middle and lower shore. At each station three replicate core samples (0.01m2) were taken to a depth of 15cm and all within 1m2 of each other, approximately from the centre of each distinct habitat or biotope. Samples were placed in pre-labelled plastic bags and transferred to labelled, clean plastic buckets at the end of each survey day. The samples were sieved through a 0.5mm sieve and fixed used 4% buffered formaldehyde solution containing Rose Bengal vital stain, within 10 hours of collection. Macrofaunal organisms within the samples were identified to species level where possible, and enumerated. where only part of an organism was identified, the species was marked as 'present'. Additionally, a fourth core was taken for PSA and kept chilled during delivery to the NLS laboratory for analysis. "