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GeoBioScience: Red Wood Ants as Bioindicators for Active Tectonic Fault Systems in the West Eifel (Germany).

Berberich G, Schreiber U - Animals (Basel) (2013)

Bottom Line: The results showed linear alignments and clusters of approx. 3,000 RWA mounds.A possible cause can be found in occasionally occurring H₂S in the fault systems, which is toxic at miniscule concentrations to the ants.Viewed overall, there is a strong relationship between RWA mounds and active tectonics in the West Eifel.

View Article: PubMed Central - PubMed

Affiliation: Department of Geology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany. gabriele.berberich@uni-due.de.

ABSTRACT
In a 1.140 km² study area of the volcanic West Eifel, a comprehensive investigation established the correlation between red wood ant mound (RWA; Formica rufa-group) sites and active tectonic faults. The current stress field with a NW-SE-trending main stress direction opens pathways for geogenic gases and potential magmas following the same orientation. At the same time, Variscan and Mesozoic fault zones are reactivated. The results showed linear alignments and clusters of approx. 3,000 RWA mounds. While linear mound distribution correlate with strike-slip fault systems documented by quartz and ore veins and fault planes with slickensides, the clusters represent crosscut zones of dominant fault systems. Latter can be correlated with voids caused by crustal block rotation. Gas analyses from soil air, mineral springs and mofettes (CO₂, Helium, Radon and H₂S) reveal limiting concentrations for the spatial distribution of mounds and colonization. Striking is further the almost complete absence of RWA mounds in the core area of the Quaternary volcanic field. A possible cause can be found in occasionally occurring H₂S in the fault systems, which is toxic at miniscule concentrations to the ants. Viewed overall, there is a strong relationship between RWA mounds and active tectonics in the West Eifel.

No MeSH data available.


Related in: MedlinePlus

Comparison of the habitat requirements of the RWA mounds for the entire study area (I) and reference location Oberehe (II). Given numbers are for altitude (m above sea level) (a), exposition [°] (b), inclination [°] (c), site factor (d), height [m] (e), diameter [m] (f), site moisture (g) and type of forest stand (h).
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animals-03-00475-f006: Comparison of the habitat requirements of the RWA mounds for the entire study area (I) and reference location Oberehe (II). Given numbers are for altitude (m above sea level) (a), exposition [°] (b), inclination [°] (c), site factor (d), height [m] (e), diameter [m] (f), site moisture (g) and type of forest stand (h).

Mentions: A comparison of the habitat requirements of the RWA mounds for the entire study area and the reference location Oberehe confirmed the published ones so far [43,44,45,46,48,49,50]. Between 80% and 84% of the mapped mounds were found at altitudes of between 400 and 600 m above sea-level (cf.Figure 6(a)). Most of the RWA mounds have a very strong SE orientation, though there is also a weak SW orientation visible (cf.Figure 6(b)). In the study area and at the Oberehe site, the preferred slope angles are very shallow (0–5°) (cf.Figure 6(c)). Only 7% (study area) and 10% (Oberehe) of the total mounds were mapped at very steep slopes (>25°) with SE orientation. In the study area and at the Oberehe site the majority of mounds (99%) were mapped in forest stands (at forest roads, forest edges, logging trails, cleared woodland (cf.Figure 6(d)). Only 1% of the RWA mounds occur in unusual, non-typical locations such as road sides, embankments, creeks or private gardens. Although these sites do not meet the site requirements published in the literature so far, the mapped mounds of these unusual locations are usually several years old as confirmed by forest workers or house owners. Around one third of the mounds (34% study area, 33% Oberehe) show mound heights between 0.11 and 0.50 m. Only a fifth (20% study area) shows heights between 1.0 and 2.0 m, whereas at the Oberehe site 25% have heights between 1.0 and 2.0 m (cf.Figure 6(e)). Approximately 43% of the mounds have diameters between 1.0 and 1.5 m. However, 31.5% of the mound in the study area and 21% (Oberehe) have exceptionally large diameters of 2 m and larger (cf.Figure 6(f)). The majority of the mounds were found at dry sites (92% study area, 99% Oberehe); only a minority (8% study area, 1% Oberehe) was found on humid or wet locations (cf.Figure 6(g)). The majority of the mounds was mapped in coniferous forest stands, e.g., picea (58% study area, 55% Oberehe), approx. one third was found in mixed forest stands (e.g., picea, fagus and/or quercus) and very few were found in deciduous (fagus and/or quercus) forests (4% study area, 1% Oberehe) (cf.Figure 6(h)).


GeoBioScience: Red Wood Ants as Bioindicators for Active Tectonic Fault Systems in the West Eifel (Germany).

Berberich G, Schreiber U - Animals (Basel) (2013)

Comparison of the habitat requirements of the RWA mounds for the entire study area (I) and reference location Oberehe (II). Given numbers are for altitude (m above sea level) (a), exposition [°] (b), inclination [°] (c), site factor (d), height [m] (e), diameter [m] (f), site moisture (g) and type of forest stand (h).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4494391&req=5

animals-03-00475-f006: Comparison of the habitat requirements of the RWA mounds for the entire study area (I) and reference location Oberehe (II). Given numbers are for altitude (m above sea level) (a), exposition [°] (b), inclination [°] (c), site factor (d), height [m] (e), diameter [m] (f), site moisture (g) and type of forest stand (h).
Mentions: A comparison of the habitat requirements of the RWA mounds for the entire study area and the reference location Oberehe confirmed the published ones so far [43,44,45,46,48,49,50]. Between 80% and 84% of the mapped mounds were found at altitudes of between 400 and 600 m above sea-level (cf.Figure 6(a)). Most of the RWA mounds have a very strong SE orientation, though there is also a weak SW orientation visible (cf.Figure 6(b)). In the study area and at the Oberehe site, the preferred slope angles are very shallow (0–5°) (cf.Figure 6(c)). Only 7% (study area) and 10% (Oberehe) of the total mounds were mapped at very steep slopes (>25°) with SE orientation. In the study area and at the Oberehe site the majority of mounds (99%) were mapped in forest stands (at forest roads, forest edges, logging trails, cleared woodland (cf.Figure 6(d)). Only 1% of the RWA mounds occur in unusual, non-typical locations such as road sides, embankments, creeks or private gardens. Although these sites do not meet the site requirements published in the literature so far, the mapped mounds of these unusual locations are usually several years old as confirmed by forest workers or house owners. Around one third of the mounds (34% study area, 33% Oberehe) show mound heights between 0.11 and 0.50 m. Only a fifth (20% study area) shows heights between 1.0 and 2.0 m, whereas at the Oberehe site 25% have heights between 1.0 and 2.0 m (cf.Figure 6(e)). Approximately 43% of the mounds have diameters between 1.0 and 1.5 m. However, 31.5% of the mound in the study area and 21% (Oberehe) have exceptionally large diameters of 2 m and larger (cf.Figure 6(f)). The majority of the mounds were found at dry sites (92% study area, 99% Oberehe); only a minority (8% study area, 1% Oberehe) was found on humid or wet locations (cf.Figure 6(g)). The majority of the mounds was mapped in coniferous forest stands, e.g., picea (58% study area, 55% Oberehe), approx. one third was found in mixed forest stands (e.g., picea, fagus and/or quercus) and very few were found in deciduous (fagus and/or quercus) forests (4% study area, 1% Oberehe) (cf.Figure 6(h)).

Bottom Line: The results showed linear alignments and clusters of approx. 3,000 RWA mounds.A possible cause can be found in occasionally occurring H₂S in the fault systems, which is toxic at miniscule concentrations to the ants.Viewed overall, there is a strong relationship between RWA mounds and active tectonics in the West Eifel.

View Article: PubMed Central - PubMed

Affiliation: Department of Geology, Faculty of Biology, University of Duisburg-Essen, Universitätsstr. 5, 45141 Essen, Germany. gabriele.berberich@uni-due.de.

ABSTRACT
In a 1.140 km² study area of the volcanic West Eifel, a comprehensive investigation established the correlation between red wood ant mound (RWA; Formica rufa-group) sites and active tectonic faults. The current stress field with a NW-SE-trending main stress direction opens pathways for geogenic gases and potential magmas following the same orientation. At the same time, Variscan and Mesozoic fault zones are reactivated. The results showed linear alignments and clusters of approx. 3,000 RWA mounds. While linear mound distribution correlate with strike-slip fault systems documented by quartz and ore veins and fault planes with slickensides, the clusters represent crosscut zones of dominant fault systems. Latter can be correlated with voids caused by crustal block rotation. Gas analyses from soil air, mineral springs and mofettes (CO₂, Helium, Radon and H₂S) reveal limiting concentrations for the spatial distribution of mounds and colonization. Striking is further the almost complete absence of RWA mounds in the core area of the Quaternary volcanic field. A possible cause can be found in occasionally occurring H₂S in the fault systems, which is toxic at miniscule concentrations to the ants. Viewed overall, there is a strong relationship between RWA mounds and active tectonics in the West Eifel.

No MeSH data available.


Related in: MedlinePlus