Project part-financed by the European Union (European Regional Development Fund)

The Interreg IVB North Sea Region Programme


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Rönnebecker Sand

Degree of synergistic effects according to Natura 2000 aims

The Rönnebecker Sand is located in a Special Protection Area (SPA) after the Habitat Directive (Site Name: Nebenarme der Weser mit Strohauser Plate und Juliusplate; site code: DE 2516-331). According to the Integrated Management Plan Weser (IBP Weser), the project area is assigned to operational area 3. Although the compensation measure was not designed to meet the requirements of Natura 2000, potential positive effects on several conservation objectives defined for operational area 3 (Table 3) and for the entire investigation area of the IBP Weser (Table 4) can be stated.

-Step 1: Estimate potential measure effects on conservation objectives for certain special units

Table 3: Natura 2000-objectives with specifications for operational area 3 (source: simplified after NLWKN, SUBV 2012)
Operational area 3: Freshwater zone in the lower Weser (Weser km 12 - 32)
Specifications for operational area 3 Effect of measure 25 on conservation objectives Short explanation
positive effect no effect negative effect
Conservation and development of specific estuarine habitats and (tidal) floodplains and their dynamic changes
Development, enlargement and upgrade of shallow water zones with moderate current climate ++     A shallow water zone with reduced tidal range was created.
Development of passable shore structures +     The shallow water zone is connected to the Weser River by an overflow barrier which is basically passable for organisms.
Conservation and development of typical habitats of operational area 3 (e.g. river flats, reeds and typical shore vegetation not being affected by neophytes, tidal floodplains and extensively used grasslands) in a dimension, spatial distribution and interconnection ensuring long-term appearance of typical species  ++     Typical habitats of operational area 3 were developed (e.g. reeds, extensively used grassland).
Conservation and development of tidal floodplains at the upper tidal border ++     The shallow water area Rönnebecker Sand takes over various functions of tidal floodplain back waters.
Conservation and development of habitats for viable populations and estuary and (tidal) floodplain specific species as well as species after Annex II Habitats Directive and bird species after Birds Directive
Conservation of typical breeding bird communities and associated habitats (breeding birds of grasslands, reeds and tidal floodplains) +     The project area represents a breeding site of importance for the federal state of Lower Saxony (Bios 2007a)
Conservation and development of undisturbed resting and moulting areas for migratory bird populations (high diversity, many individuals) considering all necessary functions +     The migratory bird population can be described as species and individuals rich due to structure diversity (e.g. shallow and deep water, grassland) and due to few disturbances (Bios 2007a)
Conservation and development of well-structured bordering waters and shore areas with wood, typical shore vegetation and reeds as hunting and feeding ground for Pond bat (Myotis dasycneme) +     Not investigated, but the occurrence of Pond bat is likely.
Preservation and development of spawning ground function for Twaite shad (e.g. by avoiding disturbances during spawning season) +     In 2009, some spawn of Twait shad was found in the shallow water zone. Due to low current velocities, the shallow water zone itself is not supposed to serve as spawning ground for Twaite shad. However, discharges of oxygen, zooplankton (Eurytemora affinis) and Mysida from the shallow water zone directly into the main spawning ground of Twaite shad take place and contribute to improving the growing conditions (Haesloop 2009).
Conservation and development of spawning ground function for Smelt (Osmerus eperlanus) (e.g. by avoiding disturbances during spawning season) +     Larvae and juveniles were found in the shallow water zone in 2004/2005 and in 2009 (Haesloop 2009).


-Step 2: Estimate potential measure effects on overall conservation objectives

Table 4: Natura 2000-objectives with specifications for entire investigation area of the Integrated Management Plan Weser (IBP Weser); source: simplified after NLWKN, SUBV 2012
Specifications for entire investigation area of IBP Weser Effect of measure 25 on conservation objectives?
positive effect no effect negative effect
Conservation and development of specific functions and processes of estuaries and (tidal) floodplains to reach favourable abiotic conditions and typical hydromorphological structures
Conservation and development of favourable
water structures and water bed dynamics
++    
Development of evenly distributed and reduced
current energy and tidal parameters
++    
Conservation and development of favourable
gradients of specific aspects regarding estuaries
and (tidal) floodplains (e.g. salinity, sediments,
current conditions, tidal range, close-to-nature
zonation of shore vegetation…); refers to inner
estuary and to area between estuary and floodplain
within fresh water zone.
+    
Improvement of water and sediment quality +    
Conservation and development of specific estuarine habitats and (tidal) floodplains and their dynamic changes
Conservation and development of habitats and
communities which strongly depend on the natural
dynamics of morphological processes
(e.g. mudflats, shallow waters, creeks… )
+    
Development of balanced area percentages
regarding mudflats, shallow waters, shallow and
deep sublitoral
+    
Conservation and development of tidal floodplains
with typical vegetation structures and
biocoenosis and favourable tidal and flooding
dynamics; especially floodplain enlargement
+    
Conservation and development of habitats for viable populations and estuary and (tidal) floodplain specific species as well as species of Annex II Habitats Directive and bird species of Birds Directive
Conservation of habitat functions for breeding
and migrant birds especially as feeding grounds
(also for bordering or networked areas)
+    
Conservation and development of habitat
requirements for migratory fish stocks and
cyclostomata within present territories and
networked areas
+    
Conservation and development of habitat
requirements for autochthon
fish communities with typical age composition
and typical percentage of estuarine species and
diadromous migratory fish species
+    
Conservation and development of long-term
viable populations of typical
fish species and cyclostomata
(estuarine and diadromous guilds)
+    
Reaching of favourable water quality for
reproduction, larval development and
viability of typical fish communities of different
salinity zones
+    
Conservation and development / reestablishment of
passability of the tidal river Weser and its
tributaries for migratory fish and benthic
invertebrates   
  0  



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Report: Management measures analysis and comparison