natura 2000 meeting –13th -15th november...
TRANSCRIPT
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Christine Pergent-Martini & Ecosystem Team
(presented by Thibaut de Bettignies)
NATURA 2000 meeting – 13th -15th November 2018
Surface evaluation : a classical tool to detect spatio-
temporal evolution (e.g. Natura 2000 sites)
But needs :
- Availability of historical data
- Accuracy, reliability, reproducibility of these mapping data
Telesca et al. 2015
Corsica
� Several cartographic data (Total Nb 293)
Molinier, 1962
Coralligenous assemb.Detritic sand
Meadows
� Concerning long/mid-term periodThe first: 1962, 71 % since 2000 & 50% since
2010
� Existence of regional data concerning
Posidonia meadow all around the islandMeinesz et al. (1990)
Pasqualini (1997) 7 1st real map of Posidonia
Programme CARTHAMED 7 continuous map of benthic habitats with a
reliability percentage based on 12 criteria
(derived from MESH (2008)
Main benthic habitats & bottom types
> 90 %
> 80%
> 75%
> 70%
> 60%
< 50 %
% of reliability
Posidonia meadows
Meinesz et al, 1990
1
2
3
45
6
7
8
9
10
1112 13
14
Pasqualini, 1997
�Regression
17 % in 5 years
But in Meinesz potential habitat
effective habitat for Pasqualini
Pasqualini, 1997 CARTHAMED 2015
� Regression
11 % in 20 years
MEDAM
BUT*
No change in coastal management since 1995
Case study : Natura 2000 site
20112006
Upper limit of Paragan
34,8 ha 37,0 ha
With same methods 7Progression of 6 %
Natura 2000 site - Grand herbier de la Plaine orientale
Pasqualini, 1997 POSIDCORSE 2016
�Regression
10 % in 20 years
Diminution of % of interpolation
No data
Continuous
data
Presence of
anthropic damages &
natural
discontinuities
Test zone: Natura 2000 site - Grand herbier de la Plaine orientale
Biggest meadow of Posidonia in Corsica
Availability of :
� A continuous map of Posidonia meadows
� A complete coverage by acoustic data
� Aerial photographs & lidar images on shallow
bottoms
Anthropogenic activities & disturbances :
� Yachting and boaters
� Fishing (3 trawlers) � Commercial shipping
Goals :� Detect mechanical impacts
� Quantify them
� Assessment of their severity
Results :
Damages due to mooring of tankers (unloading terminal) and
commercial ships (mooring in case of meteorological disturbances;
visible on Lidar Data - SHOM)
More than 700 m long !
Marks of illegal trawling (double lines) inside
the meadow (visible on sonograms and in situ)
Results :
• 98 % of scars are between -20 and
-40 m depth
• Highest density is near the lower
limit of Posidonia (very sensitive
part)
• On the way of Bastia harbour
• More than 40 scars per grid unit in
the most impacted area
• Some scars are more than 2 km
long
12
Results :
Results :
Estimation of 280 ha of
Posidonia destroyed.
4% of the whole test
zone.
Around 150 years for a total
recovering of the meadow
50 years after 150 years afterState 0
Modelisation on a spatial analysis based on the
assumption of a linear recovery of 4 cm/year.
Regulatory measures with priority 1:
Limit anchoring in the posidonia meadow of recreational vessels
Anchorage outside Posidonia meadows ☐☐☐☐
Example of measures proposed in the DOCOB – Phase 2
Identify waiting areas for ships
concerned by meteorolgical contraints
���� Areas outside Posidonia meadows
Posidonia meadow
Previous waiting area
Present waiting area
On going
���� Done
Other measures envisaged
No renewal of the licence for trawling
Setting up mooring box for boats waiting for unloading Planned in 2019
���� No deadline
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