216
pressure (Essington et al. 2006 ; Rochet et al.
2010 , 2013b ), climate change (Ainsworth et al.
2011 ; Travers-Trolet et al. 2014 ) and other environmental perturbations (Lokrantz et al. 2010 ).
Functional groups are often defi ned in an ad
hoc manner, based on the literature or local diet
data or data from other areas. A priori groups of
species are frequently used in ecosystem models,
e.g. taxonomic groups such as mollusc,
Clupeidae, etc. Some models also include dietbased groups of species (large piscivores, Banaru
et al. 2013 ). In recent years, there has been
renewed interest in grouping species using local
and species-specifi c morphological measurements (Bremner et al. 2003 ; Dumay et al. 2004 );
this ecomorphological approach is founded on
the relationship between morphology and function (e.g. Reecht et al. 2013 ).
Recent studies identifying and mapping ecosystem diversity and anthropogenic pressures in
Mediterranean Sea have underlined signifi cant
geographical patterns (Coll et al. 2010 , 2012 ;
Granger et al. 2015 ). This suggests that species
composition of the Mediterranean marine communities varies among geographic areas.
In this example, we characterized the temporal changes of three contrasted Mediterranean
areas using a posteriori functional groups of species defi ned by species-specifi c morphological
traits. The three areas vary in terms of total surface, degree of enclosure, nutrient inputs and/or
fi shing efforts (e.g. Caddy et al. 1995 ; Coll
et al. 2012 ). The Gulf of Lions is a highly productive area with a wide shelf in the western
Mediterranean basin. Its productivity is notably
due to high run-offs by the Rhône river and local
hydrographic features. It supports numerous fi sheries and ranges among the most fi shed areas of
the Mediterranean Sea together with the Aegean
Sea (Coll et al. 2012 ). The Aegean Sea is a semienclosed area with a north to south decreasing
gradient of productivity, highly correlated with
nutrient enrichment patterns. The Ionian Sea is
more open and less productive than the other two.
According to Coll et al. ( 2012 ), trawling and
dredging disturbances are less important than in
the two other areas.
The biological data (fi sh and invertebrate biomass) were collected during annual bottom trawl
surveys conducted in May to July from 1994 to
2012 for the Gulf of Lions, 1995–2012 for the
Ionian Sea and 1996–2008 for the Aegean Sea.
Ten morphological traits (8 continuous and 2 categorical) were measured in the fi eld and on
photographs.
Cluster analysis of morphological traits identifi ed ten FGs (Fig. 2 ). It fi rst discriminated
between benthic and pelagic species, and within
each group, it distinguished species by their diet
(e.g. strictly invertebrate and mixed piscivores
and invertebrate feeders). For instance, FG5
grouped small pelagic species such as sardines
and anchovies which feed mainly on zooplankton
and inhabit the water column, while FG2 was
characterized by fl atfi sh which feed mostly on
macroinvertebrates and live in or on soft substratum. This classifi cation was partly correlated
with trophic (5 %) and habitat guilds (19 %) as
defi ned in the literature. These low percentages
confi rm that the traits are not solely related to one
of the two functions and that similar species in
terms of morphology may be grouped together
although having some differences in their diet
(Albouy et al. 2011 ).
Temporal changes of functional group biomass in each area were assessed by computing
the difference in biomass between the beginning
(3 fi rst years) and the end (fi nal 3 years) of the
time series. The three Mediterranean areas displayed differences in their FG time trends, with
the Ionian Sea contrasting highly with the two
other areas. Almost all FGs from the Ionian Sea
increased over time by up to 378 %. Concurrently,
nearly all the pelagic FGs of the three areas
Fig. 1 DPSIR indicator framework for ecosystem-based
management
V. Trenkel et al.
pressure (Essington et al. 2006 ; Rochet et al.
2010 , 2013b ), climate change (Ainsworth et al.
2011 ; Travers-Trolet et al. 2014 ) and other environmental perturbations (Lokrantz et al. 2010 ).
Functional groups are often defi ned in an ad
hoc manner, based on the literature or local diet
data or data from other areas. A priori groups of
species are frequently used in ecosystem models,
e.g. taxonomic groups such as mollusc,
Clupeidae, etc. Some models also include dietbased groups of species (large piscivores, Banaru
et al. 2013 ). In recent years, there has been
renewed interest in grouping species using local
and species-specifi c morphological measurements (Bremner et al. 2003 ; Dumay et al. 2004 );
this ecomorphological approach is founded on
the relationship between morphology and function (e.g. Reecht et al. 2013 ).
Recent studies identifying and mapping ecosystem diversity and anthropogenic pressures in
Mediterranean Sea have underlined signifi cant
geographical patterns (Coll et al. 2010 , 2012 ;
Granger et al. 2015 ). This suggests that species
composition of the Mediterranean marine communities varies among geographic areas.
In this example, we characterized the temporal changes of three contrasted Mediterranean
areas using a posteriori functional groups of species defi ned by species-specifi c morphological
traits. The three areas vary in terms of total surface, degree of enclosure, nutrient inputs and/or
fi shing efforts (e.g. Caddy et al. 1995 ; Coll
et al. 2012 ). The Gulf of Lions is a highly productive area with a wide shelf in the western
Mediterranean basin. Its productivity is notably
due to high run-offs by the Rhône river and local
hydrographic features. It supports numerous fi sheries and ranges among the most fi shed areas of
the Mediterranean Sea together with the Aegean
Sea (Coll et al. 2012 ). The Aegean Sea is a semienclosed area with a north to south decreasing
gradient of productivity, highly correlated with
nutrient enrichment patterns. The Ionian Sea is
more open and less productive than the other two.
According to Coll et al. ( 2012 ), trawling and
dredging disturbances are less important than in
the two other areas.
The biological data (fi sh and invertebrate biomass) were collected during annual bottom trawl
surveys conducted in May to July from 1994 to
2012 for the Gulf of Lions, 1995–2012 for the
Ionian Sea and 1996–2008 for the Aegean Sea.
Ten morphological traits (8 continuous and 2 categorical) were measured in the fi eld and on
photographs.
Cluster analysis of morphological traits identifi ed ten FGs (Fig. 2 ). It fi rst discriminated
between benthic and pelagic species, and within
each group, it distinguished species by their diet
(e.g. strictly invertebrate and mixed piscivores
and invertebrate feeders). For instance, FG5
grouped small pelagic species such as sardines
and anchovies which feed mainly on zooplankton
and inhabit the water column, while FG2 was
characterized by fl atfi sh which feed mostly on
macroinvertebrates and live in or on soft substratum. This classifi cation was partly correlated
with trophic (5 %) and habitat guilds (19 %) as
defi ned in the literature. These low percentages
confi rm that the traits are not solely related to one
of the two functions and that similar species in
terms of morphology may be grouped together
although having some differences in their diet
(Albouy et al. 2011 ).
Temporal changes of functional group biomass in each area were assessed by computing
the difference in biomass between the beginning
(3 fi rst years) and the end (fi nal 3 years) of the
time series. The three Mediterranean areas displayed differences in their FG time trends, with
the Ionian Sea contrasting highly with the two
other areas. Almost all FGs from the Ionian Sea
increased over time by up to 378 %. Concurrently,
nearly all the pelagic FGs of the three areas
Fig. 1 DPSIR indicator framework for ecosystem-based
management
V. Trenkel et al.