Environmental change in theRía deVigo,NW Iberia, since the mid‐Holocene: new palaeoecological and seismic evidence

Abstract

2012 (October): Environmental change in the Ría de Vigo, NW Iberia, since the mid-Holocene: new palaeoecological and seismic evidence.

Temporal stability and directional change in a color cline of a marine snail from NW Spain

“…In the case of temperature, for instance, Phifer-Rixey et al (2008) provide experimental evidence that thermal stress tolerance might be driving a color cline in L. obtusata from the Gulf of Maine. As for salinity, which also shows a concentration gradient over the Ría (e.g., Muñoz Sobrino et al 2012 ; this study), its positive regression coefficients with lineata frequency and negative with fulva frequency suggest that it constitutes another selective pressure operating along the cline. In this sense, previous experimental evidence exists that the different color morphs of L. saxatilis from the White Sea have different saline-stress tolerance ( Sokolova and Berger 2000 ), although the molecular mechanisms for such association are not known yet (see also Minton and Gunderson 2001 for a similar case in a different gastropod species).…”

“…A much more plausible explanatory mechanism might involve some form of natural selection. In addition to the temporal stability and spatial replication of the cline (which by its own right might already suggest the action of selective forces; Endler 1986 ), the main reason for this is that there are strong environmental gradients (e.g., temperature, salinity, CO 2 , and wave exposure) along the Ría de Vigo that go parallel to the color cline ( Ruiz-Villareal et al 2002 ; Gago et al 2003 ; Muñoz Sobrino et al 2012 ; Ibánhez et al 2021 ). These environmental gradients might give rise to differential selective pressures that end up maintaining the cline in a relatively stable form.…”

“…These data were taken on 4 consecutive days during October 2022 using a sampling quadrat (diameter = 60 cm) and following a semiquantitative procedure similar to the Ballantine scale (used to estimate wave exposure; Ballantine 1961 ; see also Raffaelli and Hawkins 1996 ; Little et al 2009 ). For this, semiquantitative scales and presence/absence classes for key ecological parameters of the intertidal ecosystem were created based on relevant parameters for the Rías Baixas as derived from key published sources ( Rolán 1990 ; Méndez and Vilas 2005 ; Muñoz Sobrino et al 2012 ). Semiquantitative procedures such as the Ballantine scale constitute a useful approach when dealing with large geographical scales (such as the Ría de Vigo; ~41 km bordering the northern coast, and ~57 km the southern coast), and can provide insights into the main ecological trends at play in intertidal ecosystems ( Raffaelli and Hawkins 1996 ; Burrows et al 2008 ; Little et al 2009 ).…”

After the fire: the end of a house life-cycle at the Iron Age site of Nabás (North-western Iberia)

“…In line with these changes, the trend of progressive woodland retreat continued during the first millennium BC (Gómez-Orellana et al 1996;Muñoz Sobrino et al 2014), with a synchronous development of heathland communities of Erica, Calluna, Cistus and Ulex (Muñoz- Sobrino et al 2012Sobrino et al , 2014Sobrino et al , 2016. According to the available pollen data, the forest canopy was dominated by deciduous Quercus trees, Corylus avellana shrubs and mesic genera such as Alnus, Betula and Salix.…”

“…After 500 cal BC, the occurrence of human-related taxa becomes more frequent, a process that is coeval with evidence of erosive dynamics that has been linked to the development of forest clearances resulting from human activities (Fábregas-Valcarce et al 2003;Muñoz Sobrino et al 2012). Pollen analysis of marine and intertidal quaternary sedimentary deposits (Gómez-Orellana et al 1996;Desprat et al 2003;Muñoz Sobrino et al 2007Costas et al 2009) provides an insight into the vegetation history of southwest Galicia during the Holocene, but precise information on vegetation evolution during the first millennium BC and the beginning of the first century AD is not abundant due to chronological uncertainties and lack of data.…”