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species are Gobius cobitis , Lipophrys pavo, and Trypterigion tripteronotus on shallow
infralittoral rocks; Pomatoschistus marmoratus , Solea vulgaris, and Solea impar on
sandy bottoms; and Syngnathus abaster , Hippocampus ramulosus, and Gobius niger
on Cymodocea nodosa-Caulerpa prolifera mixed beds.
The lagoon also provides a habitat for many migratory seabirds. Its margins and
islands attract nidificate species of international relevance such as Himantopus
himantopus , Recurvirostra avosetta , Charadrius alexandrinus, and Sterna albifron,
and others such as Sterna hirundo , Tadorna tadorna , Anas platyrrhynchos, Burhinus
oedicnemus , Larus ridibundus, and Larus cachinnans . Marginal lagoons exploited
for salt mining shelter stable colonies of flamingos ( Phoenicopterus ruber ), which
reach concentrations of up to 1000 individuals.
9.3.2
R ECENT H ISTORY OF C HANGES IN THE L AGOON R ESULTING
FROM H UMAN A CTIVITIES
The Mar Menor has attracted humans since ancient times, and it has been the target
of various types of aggression during its recent history. Since the early 1970s, tourist
development has increased the demand for recreational facilities, resulting in the
creation of new beaches, harbors, and channels. Mining, urban development, and
changes in agricultural practices have increased the waste input into the lagoon.
Many of these activities led to environmental changes that affected the biota and
changed the configuration of the lagoon.
One of the first impacts on the lagoon environment caused by human activities
resulted from the input of terrestrial materials, which increased the sedimentation
rates from 30 mm/century to 30 cm/century as a consequence of the deforestation
of the surrounding land for agricultural and pastural use during the 16th and 17th
centuries. 28,29 Another ancient activity that developed in the Mar Menor area, begin-
ning in 2000 B . C ., was mining (argent, iron, lead, zinc, copper, and nickel among
other minerals) in the southern mountains. The maximum extractive capacity
occurred from 1960 to 1980 but mining continued until 1990. Waste from the barren
mining lands was emptied into watercourses flowing into the south side of the Mar
Menor until 1950. It was then diverted to silt Portman Bay (64 ha, 20 m depth) on
the Mediterranean coastline facing the south. Although mining waste to the Mar
Menor was stopped more than 50 years ago, the heavy metal concentration in
sediment, specially in the southern part of the lagoon, still remains high and constant
(mean values
g/g of lead and zinc) 28-30 ( Figure 9.3.8) .
Two marginal lagoons are at present used for salt mining. An additional four
lagoons experienced either a natural process of filling up by sediment or were drained
for agricultural use or urban development. This process has contributed to the reduction
of the Mar Menor surface (from 185 km 2 in 1868, to 172 km 2 in 1927, 138 km 2 in
1947, to 135 km 2 in 1969 with a slight reduction since then (Figure 9.3.9) and a
reduction in depth ( Figure 9.3.10) ). 5,29
Records of the first tourist settlements date from the first half of the 19th century.
Since then the lagoon has attracted an increasing seasonal population. The census of
local population that lived year round in the Mar Menor for the year 2000 was 45,584
whereas the stable tourist population during the high season (July to September) was
2000
µ
 
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