communities based on the assumption that the community grows deeper - PowerPoint PPT Presentation

Lower depth limit of macrophyte communities • based on the assumption that the community grows deeper the more favourable the growth conditions are • the depth limit should be measures at the depth where the community has a 10% coverage value • pre-core indicator • under development

Policy relevance of the pre-core indicator Primary importance Secondary importance BSAP Thriving and balanced communities of none stated Segment and plants and animals Objective Natural marine landscapes MSFD 1.4 Habitat distribution 1.5 Habitat extent (area, only as proxy) Descriptors and 1.6. Habitat condition Criteria 4.3 Abundance/distribution of key trophic groups and species (habitat defining species) 6.1 Substrate characteristics Other relevant Ecological status indicator for WFD in legislation: five HELCOM countries (e.g. WFD)

GES-boundary concept • the reference value of lower depth limit to be applied throughout the Baltic Sea due to the biogeographic and ecological differences between assessment units • WFD coastal types and water bodies are smallest assessment units • GES-boundary is defined as 20% acceptable deviation from reference value • community-specific reference values have to be used between soft and hard bottom communities

Requirements Indicator is not applicable if: • depth limit of macrophytes is limited by substrate (e.g. lack of hard substrate in exposed areas) • no dense macrophyte stands naturally occurs in an assessment unit • assessemnt unit is not deep enough

Applicability • applicable in all coastal areas • usable in soft, hard and mixed bottoms – in all cases specific reference conditions needed – in suitable areas with soft or mixed bottoms depth limit of charophytes or higher plants to be used

Preliminary asssessment unit specific GES-boundaries • set by Estonia and Germany ID HELCOM_ID Assessment unit Macrophyte community type preliminary GES-boundaries [meter] name 15 EST-003 1 mixed (soft and hard bottom) 5,6 16 EST-004 2 mixed (soft and hard bottom) 2,8 17 EST-005 3 hard bottom 8,4 18 EST-006 4 hard bottom 8,4 19 EST-007 5 mixed (soft and hard bottom) Not applicable 20 EST-008 6 hard bottom 6,7 ID HELCOM_ID Assessment unit Macrophyte community type preliminary GES-boundaries [meter] name 112 GER-002 soft bottom 6,0 B2b_MV 113 GER-003 soft bottom 4,4 B2b_MV 114 GER-005 soft bottom 5,1 B2a_MV 115 GER-006 soft bottom 7,0 B3b_MV 116 GER-007 soft bottom 2,4 B1_MV 117 GER-008 soft bottom 2,4 B1_MV 137 GER-029 hard bottom 17,6 B4_SH 138 GER-024 soft bottom 2,2 B2a_SH 139 GER-033 soft bottom 7,0 B3b_SH 140 GER-036 soft bottom 7,0 B3b_SH