Widespread rocky reef occurrence in the central English Channel and the implications for predictive habitat mapping

Diesing, Markus; Coggan, Roger; Vanstaen, Koen

doi:10.1016/j.ecss.2009.05.018

Cited by 43 publications

(22 citation statements)

References 18 publications

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“…4). The classification classes were decided based on previous studies using the BTM classification tool with success (Diesing et al, 2009;Lundblad et al, 2006). The thresholds for the fine-and broad-scale BPIs were in previous studies often defined as 1 SD (Lundblad et al, 2006;Verfaillie et al, 2007); however, thresholds of 0.5 SD have also previously been applied (Kaskela et al, 2012).…”

Section: Geomorphometric Classification Analysismentioning

confidence: 99%

“…The tool is an extension to ArcGIS Spatial Analyst, originally used for analysing MBES data (Diesing et al, 2009;Lundblad et al, 2006;Rinehart et al, 2004). The BTM classification tool uses fine-and broad-scale bathymetric position indexes (BPIs) (Verfaillie et al, 2007) in a multiple-scale terrain analysis to classify fine-and broad-scale geometrical features.…”

Section: Geomorphometric Classification Analysismentioning

confidence: 99%

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Processing and performance of topobathymetric lidar data for geomorphometric and morphological classification in a high-energy tidal environment

Andersen

Gergely

Al-Hamdani

et al. 2017

Hydrol. Earth Syst. Sci.

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Abstract. The transition zone between land and water is difficult to map with conventional geophysical systems due to shallow water depth and often challenging environmental conditions. The emerging technology of airborne topobathymetric light detection and ranging (lidar) is capable of providing both topographic and bathymetric elevation information, using only a single green laser, resulting in a seamless coverage of the land-water transition zone. However, there is no transparent and reproducible method for processing green topobathymetric lidar data into a digital elevation model (DEM). The general processing steps involve data filtering, water surface detection and refraction correction. Specifically, the procedure of water surface detection and modelling, solely using green laser lidar data, has not previously been described in detail for tidal environments. The aim of this study was to fill this gap of knowledge by developing a step-by-step procedure for making a digital water surface model (DWSM) using the green laser lidar data. The detailed description of the processing procedure augments its reliability, makes it user-friendly and repeatable. A DEM was obtained from the processed topobathymetric lidar data collected in spring 2014 from the Knudedyb tidal inlet system in the Danish Wadden Sea. The vertical accuracy of the lidar data is determined to ±8 cm at a 95 % confidence level, and the horizontal accuracy is determined as the mean error to ±10 cm. The lidar technique is found capable of detecting features with a size of less than 1 m 2 . The derived high-resolution DEM was applied for detection and classification of geomorphometric and morphological features within the natural environment of the study area. Initially, the bathymetric position index (BPI) and the slope of the DEM were used to make a continuous classification of the geomorphometry. Subsequently, stage (or elevation in relation to tidal range) and a combination of statistical neighbourhood analyses (moving average and standard deviation) with varying window sizes, combined with the DEM slope, were used to classify the study area into six specific types of morphological features (i.e. subtidal channel, intertidal flat, intertidal creek, linear bar, swash bar and beach dune). The developed classification method is adapted and applied to a specific case, but it can also be implemented in other cases and environments.

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Section: Geomorphometric Classification Analysismentioning

confidence: 99%

Section: Geomorphometric Classification Analysismentioning

confidence: 99%

Processing and performance of topobathymetric lidar data for geomorphometric and morphological classification in a high-energy tidal environment

Andersen

Gergely

Al-Hamdani

et al. 2017

Hydrol. Earth Syst. Sci.

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“…In the context of the study aims, the study provided preliminary ecological quantitative information, which can assist regulatory bodies and developers begin to define ecological interactions with marine tidal energy developments. However, further experimental testing of the study's method design is recommended, for scientific rigour and in-depth analysis of ecological responses with tidal energy devices (Diesing et al, 2009;Hermant et al, 2010;Osalusi et al, 2009). For example, a proportion of unexplained variation and interaction was identified between the abundance and tidal velocity rates for both annual trials (ᵟ (from analysis of deviance) 2009 ¼ 35%, ᵟ 2010 ¼ 86%), with the 2010 trial outlining considerable unexplained variation.…”

Section: Combined Survey Methods: Caveats and Future Approachesmentioning

confidence: 99%

In-situ ecological interactions with a deployed tidal energy device; an observational pilot study

Broadhurst

Barr²

2014

Ocean & Coastal Management

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“…Shear stresses are generally highest in the central English Channel (e.g. Pingree and Griffiths, 1979); however, substrates are too coarse to be frequently disturbed, and in places, bedrock is exposed at the seabed (Diesing et al, 2009;. Sand and muddy sand are the most widespread substrates in the GNS, occurring close to the coast and on shallow, exposed banks, as well as in relatively deep waters of the northern North Sea (Figure 1).…”

Section: Physical Disturbance Of the Seabedmentioning

confidence: 99%

“…Bedrock outcrops are present within the study site (e.g. Diesing et al, 2009;Diesing, 2011, 2012) but we did not include rock in the assessment because rock is spatially limited and accounts for just over 1% of area of seabed and is not subject to natural disturbance in the way we have defined it (see below). The spatial distribution of biological zones (Cameron and Askew, 2011) is shown in Figure 1 (right panel).…”

Section: Study Sitementioning

confidence: 99%

A proposed method for assessing the extent of the seabed significantly affected by demersal fishing in the Greater North Sea

Diesing

Stephens

Aldridge

2013

ICES Journal of Marine Science

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The widespread impact of bottom towed fishing gear on benthic species and communities has long been recognized. The responses to a given intensity of fishing disturbance can be influenced by the extent to which these species and communities are preconditioned to disturbance by natural processes, in particular waves and currents. The advent of vessel monitoring system (VMS) and models of natural disturbance enable high-resolution and large-scale comparisons of fishing and natural disturbance. VMS data were employed to estimate the trawled area per 12 km by 12 km grid cell. We then quantified natural disturbance by estimating the number of days in a year the seabed was disturbed by tides and waves. As natural disturbance acts on large spatial scales, we assumed that each natural disturbance event affects whole grid cells. Frequencies could thus be translated into an area of impact, allowing us to compare fishing with natural disturbance. We show how such comparisons can be used to estimate the extent of different seabed substrate types significantly affected by demersal fishing. A measure of the probability that fishing disturbance exceeds natural disturbance provides one metric for identifying areas of significant trawling impact on seabed habitats and might be used to measure progress towards achieving good environmental status for sea-floor integrity within the context of the European Union's Marine Strategy Framework Directive. For more than half the seabed in the English sector of the Greater North Sea, the results suggest that disturbance attributable to demersal fishing exceeds natural disturbance based on data from the years 2006 to 2008. The imbalance between natural and fishing disturbance is greatest in muddy substrates and deep circalittoral habitats.

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Widespread rocky reef occurrence in the central English Channel and the implications for predictive habitat mapping

Cited by 43 publications

References 18 publications

Processing and performance of topobathymetric lidar data for geomorphometric and morphological classification in a high-energy tidal environment

Processing and performance of topobathymetric lidar data for geomorphometric and morphological classification in a high-energy tidal environment

In-situ ecological interactions with a deployed tidal energy device; an observational pilot study

A proposed method for assessing the extent of the seabed significantly affected by demersal fishing in the Greater North Sea

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