245
(b) Climate variability effects, such as ENSO phenomenon that modifies the seasonal evolving and other intra-annual cycles, generating a significant interannual variation in sea-level, sea surface temperature, air temperature, rainfall
and river discharges;
(c) Anthropic effects, some of the contemporary, such as real estate demand,
change of land uses, competition for water, the increase of recreation activities
associated with the transit of vehicles on coastal dunes, as well as past activities, like the construction of a damn in Rapel river (basin that represents the
southern limit of El Yali), which represented a cutoff in the contribution of sand
to beaches and coastal dunes in this area; and
(d) The recurrent earthquakes, tsunamis and ocean swells that have affected this
zone, producing morphological changes due to co-seismic vertical movements,
eroding beaches and sand dunes and changing the characteristics of the water
body by seawater intrusion.
These changes appear to have accelerated as consequence of the earthquake and
tsunami of February 2010. Even when in 2009 some problems of environmental
quality were already detected in the wetland system, when Figueroa et al. (2009)
utilized the index of conservation of lentic ecosystems (ECELS, proposed by the
Catalan Water Agency 2004) and found that El Yali characteristics qualified as regular to bad, some bird census showed a high biodiversity (Vilina et al. 2014) and there
were no signs of severe degradation. After that event, a permanent monitoring is
being carried out in this area. This monitoring program allowed registering a dramatic decrease of waterbodies extension, especially in inner lagoons, the loss of
regeneration capacity of beaches and coastal dunes, the appearance of new vegetal
species and presence of invasive flora and fauna, and the massive death of the
amphibian Calyptocephalella gayi (Acuña-O et al. 2014; Mizobe et al. 2014),
known as the big Chilean frog, a specie in danger of extinction and endemic of
Chile. This chapter is based on the information obtained from this monitoring program. Additionally, an initiative funded by Parks Canada allowed carrying out a
study to plan the ecological restoration of the area. That study provided information
to define the base line and objectives for restoration. Currently, the restoration plan
is in its initial stage of implementation.
In the littoral zone of central Chile there is a confluence of at least two aspects
that have influenced the formation of numerous coastal wetlands:
(a) The oceanic Nazca tectonic plate is slipping beneath the continental South
America plate at a relative rate of 8 cm/year and with a convergence angle of 78°
at NE (Pardo et al. 2001) provokes an imperceptible but continuous lifting of the
South American Plate. On the other hand, this same process is responsible of
episodic big earthquakes subduction (Mw >8.0) in this zone. These earthquakes
produce important horizontal and vertical co-seismic movements (Farías et al.
2010; Quezada et al. 2012a; Wesson et al. 2015). This process alone is able to
form a coastal lagoon, as in the case of El Yali. But this process can also destroy
coastal wetlands, as in the case of Tubul-Raqui wetland (37°13′S; 73°26′W),
which, with an extension of 2000 ha, suffered a co-seismic lifting of 1.6 m during
8 El Yali National Reserve: A System of Coastal Wetlands in the Southern…
(b) Climate variability effects, such as ENSO phenomenon that modifies the seasonal evolving and other intra-annual cycles, generating a significant interannual variation in sea-level, sea surface temperature, air temperature, rainfall
and river discharges;
(c) Anthropic effects, some of the contemporary, such as real estate demand,
change of land uses, competition for water, the increase of recreation activities
associated with the transit of vehicles on coastal dunes, as well as past activities, like the construction of a damn in Rapel river (basin that represents the
southern limit of El Yali), which represented a cutoff in the contribution of sand
to beaches and coastal dunes in this area; and
(d) The recurrent earthquakes, tsunamis and ocean swells that have affected this
zone, producing morphological changes due to co-seismic vertical movements,
eroding beaches and sand dunes and changing the characteristics of the water
body by seawater intrusion.
These changes appear to have accelerated as consequence of the earthquake and
tsunami of February 2010. Even when in 2009 some problems of environmental
quality were already detected in the wetland system, when Figueroa et al. (2009)
utilized the index of conservation of lentic ecosystems (ECELS, proposed by the
Catalan Water Agency 2004) and found that El Yali characteristics qualified as regular to bad, some bird census showed a high biodiversity (Vilina et al. 2014) and there
were no signs of severe degradation. After that event, a permanent monitoring is
being carried out in this area. This monitoring program allowed registering a dramatic decrease of waterbodies extension, especially in inner lagoons, the loss of
regeneration capacity of beaches and coastal dunes, the appearance of new vegetal
species and presence of invasive flora and fauna, and the massive death of the
amphibian Calyptocephalella gayi (Acuña-O et al. 2014; Mizobe et al. 2014),
known as the big Chilean frog, a specie in danger of extinction and endemic of
Chile. This chapter is based on the information obtained from this monitoring program. Additionally, an initiative funded by Parks Canada allowed carrying out a
study to plan the ecological restoration of the area. That study provided information
to define the base line and objectives for restoration. Currently, the restoration plan
is in its initial stage of implementation.
In the littoral zone of central Chile there is a confluence of at least two aspects
that have influenced the formation of numerous coastal wetlands:
(a) The oceanic Nazca tectonic plate is slipping beneath the continental South
America plate at a relative rate of 8 cm/year and with a convergence angle of 78°
at NE (Pardo et al. 2001) provokes an imperceptible but continuous lifting of the
South American Plate. On the other hand, this same process is responsible of
episodic big earthquakes subduction (Mw >8.0) in this zone. These earthquakes
produce important horizontal and vertical co-seismic movements (Farías et al.
2010; Quezada et al. 2012a; Wesson et al. 2015). This process alone is able to
form a coastal lagoon, as in the case of El Yali. But this process can also destroy
coastal wetlands, as in the case of Tubul-Raqui wetland (37°13′S; 73°26′W),
which, with an extension of 2000 ha, suffered a co-seismic lifting of 1.6 m during
8 El Yali National Reserve: A System of Coastal Wetlands in the Southern…