reflects the fact that this subregion is immersed in a conjunction point of three
ecoregions (Spalding et al. 2007). A quasi-permanent zone of upwelling influences
the flora and landscape of this subregion, providing relatively stable environmental
conditions. The central subregion spans from Calaburras to Punta Entinas (Almería),
and lacks typical Atlantic or Mediterranean communities, besides holding the lowest
species richness and a less differentiated flora. Mytilus beds are shared with the
western subregion as an important element of its landscape and species composition,
but combined with some other characteristic species of this subregion such as
Corallina spp., Gongolaria spp., Ericaria spp. or Halopteris scoparia, and a great
number of species with widespread distribution (Cebrián and Ballesteros 2004).
Fluctuating temperature and nutrient availability, related to strong upwelling processes and incoming of Mediterranean surface waters, may explain the dominance of
filter-feeder organisms (Vargas-Yáñez et al. 2002; Bermejo et al. 2015, 2016). As
with other marine organisms in Alboran, this coastal section includes the distribution
limits of both Atlantic and Mediterranean species, such as F. guiryi and P. oceanica,
respectively. The eastern subregion covers from Punta Entinas to Cabo de Palos
(Murcia) and shows a typical Mediterranean flora and marine landscape, characterized by slow-growing Gongolaria spp., Ericaria spp. and extended P. oceanica
meadows, together with several Mediterranean endemics such as Acetabularia
acetabulum or Halimeda tuna (Ballesteros and Pinedo 2004). This flora differs
greatly from the two other subregions, due to the wider thermal amplitude along
the year, and the prevalence of oligotrophic waters due to the dynamics of the water,
which favours slow-growing species (Duarte 1995).
11.4 Patterns of Distribution of Species
The Alboran Sea is also notable for the diverse biogeographic relationship of its
biota since it is a confluence area of the Lusitanian, Mauritanian, and Mediterranean
biogeographical regions. In fact, several biotic elements are distinguishable within
Alboran, namely the endemic Mediterranean, Atlanto-Mediterranean, African, and
Boreal, with some species strictly endemic to the Alboran Sea.
Some species appear to be endemic to the Alboran Sea with very small distribution ranges (Fig. 11.4), such as the molluscs Tritia tingitana (Pallary 1901) and
Cassiella abylensis (Gofas 1998) in the Strait of Gibraltar, or Trophonopsis
alboranensis (Smriglio et al. 1997) on the Alboran platform. In other less thoroughly
known groups, there are also species only recorded from the Alboran Sea (sometimes, only recorded from their type locality) but it is difficult to know if their range
is indeed restricted, or it is an artefact created by a limited sampling range. For
instance, although a fish species does exist with the specific name “alboranensis”,
Protogrammus alboranensis (Farias et al. 2016), it has been posteriorly found
outside the Alboran Sea.
Among the Mediterranean endemic biotic element, the most notable is the
seagrass, Posidonia oceanica, which reaches its western limit in Estepona and has
440
R. Real et al.
ecoregions (Spalding et al. 2007). A quasi-permanent zone of upwelling influences
the flora and landscape of this subregion, providing relatively stable environmental
conditions. The central subregion spans from Calaburras to Punta Entinas (Almería),
and lacks typical Atlantic or Mediterranean communities, besides holding the lowest
species richness and a less differentiated flora. Mytilus beds are shared with the
western subregion as an important element of its landscape and species composition,
but combined with some other characteristic species of this subregion such as
Corallina spp., Gongolaria spp., Ericaria spp. or Halopteris scoparia, and a great
number of species with widespread distribution (Cebrián and Ballesteros 2004).
Fluctuating temperature and nutrient availability, related to strong upwelling processes and incoming of Mediterranean surface waters, may explain the dominance of
filter-feeder organisms (Vargas-Yáñez et al. 2002; Bermejo et al. 2015, 2016). As
with other marine organisms in Alboran, this coastal section includes the distribution
limits of both Atlantic and Mediterranean species, such as F. guiryi and P. oceanica,
respectively. The eastern subregion covers from Punta Entinas to Cabo de Palos
(Murcia) and shows a typical Mediterranean flora and marine landscape, characterized by slow-growing Gongolaria spp., Ericaria spp. and extended P. oceanica
meadows, together with several Mediterranean endemics such as Acetabularia
acetabulum or Halimeda tuna (Ballesteros and Pinedo 2004). This flora differs
greatly from the two other subregions, due to the wider thermal amplitude along
the year, and the prevalence of oligotrophic waters due to the dynamics of the water,
which favours slow-growing species (Duarte 1995).
11.4 Patterns of Distribution of Species
The Alboran Sea is also notable for the diverse biogeographic relationship of its
biota since it is a confluence area of the Lusitanian, Mauritanian, and Mediterranean
biogeographical regions. In fact, several biotic elements are distinguishable within
Alboran, namely the endemic Mediterranean, Atlanto-Mediterranean, African, and
Boreal, with some species strictly endemic to the Alboran Sea.
Some species appear to be endemic to the Alboran Sea with very small distribution ranges (Fig. 11.4), such as the molluscs Tritia tingitana (Pallary 1901) and
Cassiella abylensis (Gofas 1998) in the Strait of Gibraltar, or Trophonopsis
alboranensis (Smriglio et al. 1997) on the Alboran platform. In other less thoroughly
known groups, there are also species only recorded from the Alboran Sea (sometimes, only recorded from their type locality) but it is difficult to know if their range
is indeed restricted, or it is an artefact created by a limited sampling range. For
instance, although a fish species does exist with the specific name “alboranensis”,
Protogrammus alboranensis (Farias et al. 2016), it has been posteriorly found
outside the Alboran Sea.
Among the Mediterranean endemic biotic element, the most notable is the
seagrass, Posidonia oceanica, which reaches its western limit in Estepona and has
440
R. Real et al.