benthic biotopes Torsten Berg & Birgit Heyden With input from - - PowerPoint PPT Presentation

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benthic biotopes Torsten Berg & Birgit Heyden With input from - - PowerPoint PPT Presentation

Oct 22, 2022 224 likes •406 views

Cumulative impacts on benthic biotopes Torsten Berg & Birgit Heyden With input from Kai Hoppe, Petra Schmitt, Alexander Darr, Samuli Korpinen, Lena Avellan Basic concept 2010/477/EU: indicator 6.1.2 multiple physical pressures on

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SLIDE 1

Cumulative impacts on benthic biotopes

Torsten Berg & Birgit Heyden

With input from Kai Hoppe, Petra Schmitt, Alexander Darr, Samuli Korpinen, Lena Avellan

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SLIDE 2

Basic concept

  • 2010/477/EU: indicator 6.1.2
  • multiple physical pressures on the sea floor

(fishing, dredging, disposal, marine structures)

  • Pressures act together, impacts are cumulative

(spatial+ temporal overlaps)

  • transformation of pressure to impacts
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SLIDE 3

Method

  • Biotic component: biotope map with sensitivity per

pressure

  • Consider increased sensitivity from oxygen

depletion

  • Overlay sensitivity with magnitude of pressure
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SLIDE 4

Method, simplified

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SLIDE 5

Method, comprehensive

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SLIDE 6

Method, sediment

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SLIDE 7

Method

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SLIDE 8

Method, fishing

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SLIDE 9

Method, biotopes

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SLIDE 10

Cumulation

  • One map with impact per pressure
  • Cumulation (if spatial and temporal overlap):

– On habitat loss, the degree of impact corresponds to the magnitude of pressure causing the loss – An individual „high“ impact leads to a „high“ cumulative impact

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SLIDE 11

Test settings

  • Softbottom/infauna biotope map
  • Fishing intensity from 2013 (no frequency data)
  • No actual cumulation (fishery is the only pressure)
  • Usage of vector data (mostly converted from raster

data)

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SLIDE 12

Biotopes

Biotope map of German Baltic Sea (Schiele et al. 2015)

Only soft bottom and infauna data included, HELCOM HUB level 5/6, resolution 1x1 km

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SLIDE 13

Biotope sensitivity

68 biotopes (Schiele, 2015) Biotope sensitivity

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SLIDE 14

Pressures

  • Fishing (blue grid, sum of surface

and subsurface SAR)

  • Sediment deposition (orange dots,

2km radius)

  • Dredging (red dots)
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SLIDE 15

Fishing intensity 2013

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SLIDE 16

Fishing impact 2013

CumI BSII

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SLIDE 17

Test results

  • General impact patterns are credible
  • SAR scale gives no information on absolute amount
  • f physical damage, e.g. from which point on the

scale habitat loss occurs

  • Resulting impact scale is relative
  • No correlation to BSII (which is the expected result)
  • Using multiple pressures, cumulation will only
  • ccur in spatially restricted areas – generally

fishing pressure is predominant