The Experts below are selected from a list of 264 Experts worldwide ranked by ideXlab platform

Gabriele Berberich - One of the best experts on this subject based on the ideXlab platform.

  • first in situ identification of ultradian and infradian rhythms and nocturnal locomotion activities of four colonies of red wood ants Formica Rufa group
    Journal of Biological Rhythms, 2019
    Co-Authors: Gabriele Berberich, Martin B Berberich, Arne Grumpe, Aaron M. Ellison, Christian Wohler
    Abstract:

    In situ activity patterns of 2 Formica Rufa-group species (F. pratensis; F. polyctena) were continuously studied at 4 different red wood-ant nests for 6 months in each of the years 2010, 2011, 2012, and 2016 and related to weather factors and variations in the Earth’s magnetic field. The in situ activity patterns of both species were similarly periodic and exhibited ultradian, and short- and long infradian rhythms under natural LD conditions. Crepuscular and nocturnal activities shorter than or equal to 4 h were observed in both species, especially at the new moon and first quarter after the astronomical twilight in a period of darkness in fall. We hypothesize that local variability in the Earth’s magnetic field affects these long-term activity patterns, whereas humidity and temperature were more strongly associated with ultradian rhythms (less than 20 h).

  • nests of red wood ants Formica Rufa group are positively associated with tectonic faults a double blind test
    PeerJ, 2017
    Co-Authors: Israel Del Toro, Gabriele Berberich, Martin B Berberich, Relena R Ribbons, Nathan J Sanders, Aaron M. Ellison
    Abstract:

    : Ecological studies often are subjected to unintentional biases, suggesting that improved research designs for hypothesis testing should be used. Double-blind ecological studies are rare but necessary to minimize sampling biases and omission errors, and improve the reliability of research. We used a double-blind design to evaluate associations between nests of red wood ants (Formica Rufa, RWA) and the distribution of tectonic faults. We randomly sampled two regions in western Denmark to map the spatial distribution of RWA nests. We then calculated nest proximity to the nearest active tectonic faults. Red wood ant nests were eight times more likely to be found within 60 m of known tectonic faults than were random points in the same region but without nests. This pattern paralleled the directionality of the fault system, with NNE-SSW faults having the strongest associations with RWA nests. The nest locations were collected without knowledge of the spatial distribution of active faults thus we are confident that the results are neither biased nor artefactual. This example highlights the benefits of double-blind designs in reducing sampling biases, testing controversial hypotheses, and increasing the reliability of the conclusions of research.

  • nests of red wood ants Formica Rufa group are positively associated with tectonic faults a double blind test
    bioRxiv, 2017
    Co-Authors: Israel Del Toro, Gabriele Berberich, Martin B Berberich, Relena R Ribbons, Nathan J Sanders, Aaron M. Ellison
    Abstract:

    Ecological studies aim to better understand the distribution and abundances of organisms. Yet ecological works often are subjected to unintentional biases thus an improved framework for hypothesis testing should be used. Double-blind ecological studies are rare but necessary to minimize sampling biases and omission errors and improve the reliability of research. We used a double-blind design to evaluate associations between nests of red wood ants (Formica Rufa, RWA) and the distribution of tectonic faults. We randomly sampled two regions in western Denmark to map the spatial distribution of RWA nests. We then calculated nest proximity to the nearest active tectonic faults. Red wood ant nests were eight times more likely to be found within 60 meters of known tectonic faults than were random points in the same region but without nests. This pattern paralleled the directionality of the fault system, with NNE-SSW faults having the strongest associations with RWA nests. The nest locations were collected without knowledge of the spatial distribution of active faults thus we are confident that the results are neither biased nor artefactual. This example highlights the benefits of double-blind designs in reducing sampling biases, testing controversial hypotheses, and increasing the reliability of the conclusions of research.

  • are red wood ants Formica Rufa group tectonic indicators a statistical approach
    Ecological Indicators, 2016
    Co-Authors: Gabriele Berberich, Martin B Berberich, Arne Grumpe, D Klimetzek, Christian Wohler
    Abstract:

    Abstract Recent research in seismically active areas indicated that the spatial distributions of geochemical soil gas anomalies and nests of red wood ants (RWA; Formica Rufa-group) are strongly correlated. Here we applied a modified Hough Transform (mHT) and an Iterative Mode Detection (IMD) to RWA nest positions, which we mapped in two Southwest German study areas (Black Forest and Bodanruck), to test for statistical significance of correlation with tectonic features. RWA densities in the seismically active study areas reaching up to 1600 nests/100 ha are about 100× higher than overall values for Northern and Southern Germany. Since the shape of edges of the study area was found to strongly influence the selection of distribution patterns, all subsequent analyses were carried out for circular study areas. Results of the mHT applied on the RWA nests in both study areas clearly showed several modes which correspond to preferred directions. Centres of the modes further processed by IMD transferred into a GIS as RWA prototype lines showed very dominant directions of RWA nest distributions in right lateral strike-slip mode in WNW-ESE resp. NW-SE direction but also in extension direction caused by the recent main stress field in NW-SE resp. NNW-SSE direction. It could thus be clearly shown that the large scale spatial distribution of RWA nests directly reflects significant components of the present day stress field and its accompanying conjugated shear systems: Linear alignments of RWA nests indicate the course of active degassing faults zones and nest clusters indicate area-wide geochemical anomalies respectively crosscut zones of different fault systems. Furthermore, directions of re-activated shear systems, e.g. from Eocene-Oligocene but also from Late Jurassic that had been modified by overprinting due to changes of the main stress field could be identified. Therefore, RWA prototype lines complement and clarify the shear sense and the tectonic regime identified in previous tectonic studies. The high degree of statistical significance of these results will also allow a rating with former contrasting interpretations as to the drivers of RWA distributions.

  • Early Results of Three-Year Monitoring of Red Wood Ants' Behavioral Changes and Their Possible Correlation with Earthquake Events.
    Open Access Journal, 2013
    Co-Authors: Gabriele Berberich, Martin B Berberich, Arne Grumpe, Christian Wohler, Ulrich Schreiber
    Abstract:

    Short-term earthquake predictions with an advance warning of several hours or days are currently not possible due to both incomplete understanding of the complex tectonic processes and inadequate observations. Abnormal animal behaviors before earthquakes have been reported previously, but create problems in monitoring and reliability. The situation is different with red wood ants (RWA; Formica Rufa-group (Hymenoptera: Formicidae)). They have stationary mounds on tectonically active, gas-bearing fault systems. These faults may be potential earthquake areas. For three years (2009–2012), two red wood ant mounds (Formica Rufa-group), located at the seismically active Neuwied Basin (Eifel, Germany), have been monitored 24/7 by high-resolution cameras with both a color and an infrared sensor. Early results show that ants have a well-identifiable standard daily routine. Correlation with local seismic events suggests changes in the ants’ behavior hours before the earthquake: the nocturnal rest phase and daily activity are suppressed, and standard daily routine does not resume until the next day. At present, an automated image evaluation routine is being applied to the more than 45,000 hours of video streams. Based on this automated approach, a statistical analysis of the ants’ behavior will be carried out. In addition, other parameters (climate, geotectonic and biological), which may influence behavior, will be included in the analysis.

Martin B Berberich - One of the best experts on this subject based on the ideXlab platform.

  • first in situ identification of ultradian and infradian rhythms and nocturnal locomotion activities of four colonies of red wood ants Formica Rufa group
    Journal of Biological Rhythms, 2019
    Co-Authors: Gabriele Berberich, Martin B Berberich, Arne Grumpe, Aaron M. Ellison, Christian Wohler
    Abstract:

    In situ activity patterns of 2 Formica Rufa-group species (F. pratensis; F. polyctena) were continuously studied at 4 different red wood-ant nests for 6 months in each of the years 2010, 2011, 2012, and 2016 and related to weather factors and variations in the Earth’s magnetic field. The in situ activity patterns of both species were similarly periodic and exhibited ultradian, and short- and long infradian rhythms under natural LD conditions. Crepuscular and nocturnal activities shorter than or equal to 4 h were observed in both species, especially at the new moon and first quarter after the astronomical twilight in a period of darkness in fall. We hypothesize that local variability in the Earth’s magnetic field affects these long-term activity patterns, whereas humidity and temperature were more strongly associated with ultradian rhythms (less than 20 h).

  • nests of red wood ants Formica Rufa group are positively associated with tectonic faults a double blind test
    PeerJ, 2017
    Co-Authors: Israel Del Toro, Gabriele Berberich, Martin B Berberich, Relena R Ribbons, Nathan J Sanders, Aaron M. Ellison
    Abstract:

    : Ecological studies often are subjected to unintentional biases, suggesting that improved research designs for hypothesis testing should be used. Double-blind ecological studies are rare but necessary to minimize sampling biases and omission errors, and improve the reliability of research. We used a double-blind design to evaluate associations between nests of red wood ants (Formica Rufa, RWA) and the distribution of tectonic faults. We randomly sampled two regions in western Denmark to map the spatial distribution of RWA nests. We then calculated nest proximity to the nearest active tectonic faults. Red wood ant nests were eight times more likely to be found within 60 m of known tectonic faults than were random points in the same region but without nests. This pattern paralleled the directionality of the fault system, with NNE-SSW faults having the strongest associations with RWA nests. The nest locations were collected without knowledge of the spatial distribution of active faults thus we are confident that the results are neither biased nor artefactual. This example highlights the benefits of double-blind designs in reducing sampling biases, testing controversial hypotheses, and increasing the reliability of the conclusions of research.

  • nests of red wood ants Formica Rufa group are positively associated with tectonic faults a double blind test
    bioRxiv, 2017
    Co-Authors: Israel Del Toro, Gabriele Berberich, Martin B Berberich, Relena R Ribbons, Nathan J Sanders, Aaron M. Ellison
    Abstract:

    Ecological studies aim to better understand the distribution and abundances of organisms. Yet ecological works often are subjected to unintentional biases thus an improved framework for hypothesis testing should be used. Double-blind ecological studies are rare but necessary to minimize sampling biases and omission errors and improve the reliability of research. We used a double-blind design to evaluate associations between nests of red wood ants (Formica Rufa, RWA) and the distribution of tectonic faults. We randomly sampled two regions in western Denmark to map the spatial distribution of RWA nests. We then calculated nest proximity to the nearest active tectonic faults. Red wood ant nests were eight times more likely to be found within 60 meters of known tectonic faults than were random points in the same region but without nests. This pattern paralleled the directionality of the fault system, with NNE-SSW faults having the strongest associations with RWA nests. The nest locations were collected without knowledge of the spatial distribution of active faults thus we are confident that the results are neither biased nor artefactual. This example highlights the benefits of double-blind designs in reducing sampling biases, testing controversial hypotheses, and increasing the reliability of the conclusions of research.

  • are red wood ants Formica Rufa group tectonic indicators a statistical approach
    Ecological Indicators, 2016
    Co-Authors: Gabriele Berberich, Martin B Berberich, Arne Grumpe, D Klimetzek, Christian Wohler
    Abstract:

    Abstract Recent research in seismically active areas indicated that the spatial distributions of geochemical soil gas anomalies and nests of red wood ants (RWA; Formica Rufa-group) are strongly correlated. Here we applied a modified Hough Transform (mHT) and an Iterative Mode Detection (IMD) to RWA nest positions, which we mapped in two Southwest German study areas (Black Forest and Bodanruck), to test for statistical significance of correlation with tectonic features. RWA densities in the seismically active study areas reaching up to 1600 nests/100 ha are about 100× higher than overall values for Northern and Southern Germany. Since the shape of edges of the study area was found to strongly influence the selection of distribution patterns, all subsequent analyses were carried out for circular study areas. Results of the mHT applied on the RWA nests in both study areas clearly showed several modes which correspond to preferred directions. Centres of the modes further processed by IMD transferred into a GIS as RWA prototype lines showed very dominant directions of RWA nest distributions in right lateral strike-slip mode in WNW-ESE resp. NW-SE direction but also in extension direction caused by the recent main stress field in NW-SE resp. NNW-SSE direction. It could thus be clearly shown that the large scale spatial distribution of RWA nests directly reflects significant components of the present day stress field and its accompanying conjugated shear systems: Linear alignments of RWA nests indicate the course of active degassing faults zones and nest clusters indicate area-wide geochemical anomalies respectively crosscut zones of different fault systems. Furthermore, directions of re-activated shear systems, e.g. from Eocene-Oligocene but also from Late Jurassic that had been modified by overprinting due to changes of the main stress field could be identified. Therefore, RWA prototype lines complement and clarify the shear sense and the tectonic regime identified in previous tectonic studies. The high degree of statistical significance of these results will also allow a rating with former contrasting interpretations as to the drivers of RWA distributions.

  • Early Results of Three-Year Monitoring of Red Wood Ants' Behavioral Changes and Their Possible Correlation with Earthquake Events.
    Open Access Journal, 2013
    Co-Authors: Gabriele Berberich, Martin B Berberich, Arne Grumpe, Christian Wohler, Ulrich Schreiber
    Abstract:

    Short-term earthquake predictions with an advance warning of several hours or days are currently not possible due to both incomplete understanding of the complex tectonic processes and inadequate observations. Abnormal animal behaviors before earthquakes have been reported previously, but create problems in monitoring and reliability. The situation is different with red wood ants (RWA; Formica Rufa-group (Hymenoptera: Formicidae)). They have stationary mounds on tectonically active, gas-bearing fault systems. These faults may be potential earthquake areas. For three years (2009–2012), two red wood ant mounds (Formica Rufa-group), located at the seismically active Neuwied Basin (Eifel, Germany), have been monitored 24/7 by high-resolution cameras with both a color and an infrared sensor. Early results show that ants have a well-identifiable standard daily routine. Correlation with local seismic events suggests changes in the ants’ behavior hours before the earthquake: the nocturnal rest phase and daily activity are suppressed, and standard daily routine does not resume until the next day. At present, an automated image evaluation routine is being applied to the more than 45,000 hours of video streams. Based on this automated approach, a statistical analysis of the ants’ behavior will be carried out. In addition, other parameters (climate, geotectonic and biological), which may influence behavior, will be included in the analysis.

Aaron M. Ellison - One of the best experts on this subject based on the ideXlab platform.

  • first in situ identification of ultradian and infradian rhythms and nocturnal locomotion activities of four colonies of red wood ants Formica Rufa group
    Journal of Biological Rhythms, 2019
    Co-Authors: Gabriele Berberich, Martin B Berberich, Arne Grumpe, Aaron M. Ellison, Christian Wohler
    Abstract:

    In situ activity patterns of 2 Formica Rufa-group species (F. pratensis; F. polyctena) were continuously studied at 4 different red wood-ant nests for 6 months in each of the years 2010, 2011, 2012, and 2016 and related to weather factors and variations in the Earth’s magnetic field. The in situ activity patterns of both species were similarly periodic and exhibited ultradian, and short- and long infradian rhythms under natural LD conditions. Crepuscular and nocturnal activities shorter than or equal to 4 h were observed in both species, especially at the new moon and first quarter after the astronomical twilight in a period of darkness in fall. We hypothesize that local variability in the Earth’s magnetic field affects these long-term activity patterns, whereas humidity and temperature were more strongly associated with ultradian rhythms (less than 20 h).

  • nests of red wood ants Formica Rufa group are positively associated with tectonic faults a double blind test
    PeerJ, 2017
    Co-Authors: Israel Del Toro, Gabriele Berberich, Martin B Berberich, Relena R Ribbons, Nathan J Sanders, Aaron M. Ellison
    Abstract:

    : Ecological studies often are subjected to unintentional biases, suggesting that improved research designs for hypothesis testing should be used. Double-blind ecological studies are rare but necessary to minimize sampling biases and omission errors, and improve the reliability of research. We used a double-blind design to evaluate associations between nests of red wood ants (Formica Rufa, RWA) and the distribution of tectonic faults. We randomly sampled two regions in western Denmark to map the spatial distribution of RWA nests. We then calculated nest proximity to the nearest active tectonic faults. Red wood ant nests were eight times more likely to be found within 60 m of known tectonic faults than were random points in the same region but without nests. This pattern paralleled the directionality of the fault system, with NNE-SSW faults having the strongest associations with RWA nests. The nest locations were collected without knowledge of the spatial distribution of active faults thus we are confident that the results are neither biased nor artefactual. This example highlights the benefits of double-blind designs in reducing sampling biases, testing controversial hypotheses, and increasing the reliability of the conclusions of research.

  • nests of red wood ants Formica Rufa group are positively associated with tectonic faults a double blind test
    bioRxiv, 2017
    Co-Authors: Israel Del Toro, Gabriele Berberich, Martin B Berberich, Relena R Ribbons, Nathan J Sanders, Aaron M. Ellison
    Abstract:

    Ecological studies aim to better understand the distribution and abundances of organisms. Yet ecological works often are subjected to unintentional biases thus an improved framework for hypothesis testing should be used. Double-blind ecological studies are rare but necessary to minimize sampling biases and omission errors and improve the reliability of research. We used a double-blind design to evaluate associations between nests of red wood ants (Formica Rufa, RWA) and the distribution of tectonic faults. We randomly sampled two regions in western Denmark to map the spatial distribution of RWA nests. We then calculated nest proximity to the nearest active tectonic faults. Red wood ant nests were eight times more likely to be found within 60 meters of known tectonic faults than were random points in the same region but without nests. This pattern paralleled the directionality of the fault system, with NNE-SSW faults having the strongest associations with RWA nests. The nest locations were collected without knowledge of the spatial distribution of active faults thus we are confident that the results are neither biased nor artefactual. This example highlights the benefits of double-blind designs in reducing sampling biases, testing controversial hypotheses, and increasing the reliability of the conclusions of research.

Pekka Niemela - One of the best experts on this subject based on the ideXlab platform.

  • The Role of Wood Ants (Formica Rufa group) in Carbon and Nutrient Dynamics of a Boreal Norway Spruce Forest Ecosystem
    Ecosystems, 2013
    Co-Authors: Leena Finer, Anita C Risch, Martin F Jurgensen, Timo Domisch, Mizue Ohashi, Jouni Kilpelainen, Seppo Neuvonen, Pekka Punttila, Pekka Niemela
    Abstract:

    Wood ants ( Formica Rufa group) are regarded as keystone species in boreal and mountain forests of Europe and Asia by their effect on ecosystem carbon (C) and nutrient pools and fluxes. To quantify the impact of their activity on boreal forest ecosystems, C, nitrogen (N), phosphorus (P), potassium (K) and calcium (Ca) pools and fluxes in wood ant nests (WAN), and soil were assessed along a 5-, 30-, 60-, and 100-year-old Norway spruce ( Picea abies L. Karsten) dominated successional gradient in eastern Finland. Amounts of C and nutrients in WAN increased with stand age, but contained less than 1% of total C and nutrient pools in these stands. The CO_2-efflux from nests was also insignificant, as compared to CO_2-efflux from the forest floor. Annually, the amount of C brought by wood ants into their nests as honeydew, prey and nest-building materials ranged from 2.7 to 49.3 kg ha^−1 C, but this is only 0.1–0.7% of the combined net primary production of trees and understorey in boreal forests. The difference between wood ant nest C inputs and outputs was very small in the younger-aged stands, and increased in the older stands. Carbon accumulation rates in nests over a 100 year period are estimated to be less than 10 kg ha^−1 a^−1. In contrast to C, annual inputs of N, P, and K are larger compared to wood ant nest nutrient pool size, ranging from 3 to 6% of the annual tree stand and understorey uptake. This indicates a more rapid turnover and transport of N, P, and K out of WAN, and suggests that wood ants increase the cycling rate of these nutrients in boreal forests.

  • the effect of stand age on co2 efflux from wood ant Formica Rufa group mounds in boreal forests
    Soil Biology & Biochemistry, 2012
    Co-Authors: Mizue Ohashi, Anita C Risch, Martin F Jurgensen, Timo Domisch, Leena Finer, Jouni Kilpelainen, Liselotte Sundström, Pekka Niemela
    Abstract:

    Abstract Recent studies suggest that wood ants ( Formica Rufa group) mounds are point sources of carbon dioxide (CO 2 ), which increase the heterogeneity of soil carbon (C) emissions in forest ecosystems. However, little is known about the impact of anthropogenic activities, such as logging and subsequent forest succession, on these fluxes. In this study, we measured the CO 2 efflux and temperature of wood ant mounds and the surrounding forest floor in managed Finnish boreal forests of different ages (5, 30, 60, and 100 years old) to assess how the effluxes vary with stand age. We conducted efflux measurements from the mounds and the surrounding forest floor throughout the ants' active season (May–September) and during the onset of hibernation (October). The annual CO 2 efflux was then estimated using mound or forest floor temperatures, which were measured for one year. The average annual CO 2 efflux from the ant mounds was 10.2 (±5.8 SD) kg m −2  year −1 , increasing from 3.9 (±0.3 SD) kg m −2  year −1 in the 5 year-old stands to 14.3 (±3.0 SD) kg m −2  year −1 in the 100 year-old stands. Temperatures was significantly higher in the ant mounds than in the forest floor, and the average temperature difference between mounds and forest floor increased with stand age, being the lowest in the 5 year-old (4.1 (±3.1 SD) °C) and highest in the 100 year-old stands (10.3 (±5.2 SD) °C). There were no statistical differences in the mound CO 2 efflux per volume among forest age classes, suggesting higher ant CO 2 efflux in the older stands likely come from larger ant populations in the bigger mounts. The different mound temperature regimes among stand age classes indicates that the activity of wood ants changes with forest succession, particularly after clear-cutting, which alters CO 2 efflux from the mounds. The impact of ant mounds on total CO 2 efflux from the soil, estimated from mound area and volume, respectively, increased with forest age, from 0.05 (±0.05 SD) % to 0.31 (±0.18 SD) % and from 0.05 (±0.06 SD) % to 0.90% (±1.11 SD).

  • does the mutualism between wood ants Formica Rufa group and cinara aphids affect norway spruce growth
    Forest Ecology and Management, 2009
    Co-Authors: Jouni Kilpelainen, Anita C Risch, Martin F Jurgensen, Timo Domisch, Mizue Ohashi, Leena Finer, Seppo Neuvonen, Pekka Niemela, Liselotte Sundström
    Abstract:

    Abstract Ant–aphid mutualisms, in which ants tend aphids, which in turn provide honeydew to the ants, are widespread and have been shown to affect plant growth. In boreal forests the effect of ant–aphid mutualism on tree growth can vary with stand age, because forest clear-cutting harms the ecologically most dominant ant partner in such mutualisms, wood ants (Formica Rufa group). We studied whether the mutualism between wood ants and Cinara aphids affects the growth of boreal Norway spruces (Picea abies L. Karst.) in stands of different ages. In boreal forests, conifers, unlike deciduous trees, have only few defoliating insects, and therefore we expected the growth loss of conifers due to sap sucking by aphids not to be compensated by reduced insect herbivory due to predation by wood ants. The study was conducted in medium-fertile spruce-dominated stands in eastern Finland. We used stands of four different age classes (5, 30, 60 and 100 years) and selected ten spruces heavily visited and ten spruces lightly visited by ants around five medium-sized ant mounds in each stand age class. The access of ants was blocked on half of the trees in both groups. In the 5-year-old stands, the mean annual height growth of individual heavily visited seedlings was 16.3% greater than in the ones where ant traffic was blocked, but this difference was not significant. In the 30-year-old stands, the mean annual radial growth of the heavily visited spruces was 7.3% smaller than in trees where ant traffic was blocked, and this difference was significant. The mutualism had no significant effect on the radial growth in the 60- and 100-year-old stands. In the 60-year-old stands, however, the spruces that were visited heavily prior to the beginning of the study grew significantly less relative to their past growth than the initially lightly visited trees during the study. This suggests that the ant–aphid mutualism may have long-term effects on tree growth. The ant–aphid mutualism had no significant effect on the growth at the stand level. The results indicate that ant–aphid mutualism can have a significant effect on the growth of individual spruces, but the effect is negligible at ecosystem level.

  • decomposition of organic matter and nutrient mineralisation in wood ant Formica Rufa group mounds in boreal coniferous forests of different age
    Biology and Fertility of Soils, 2008
    Co-Authors: Timo Domisch, Anita C Risch, Mizue Ohashi, Leena Finer, Jouni Kilpelainen, Liselotte Sundström, Pekka Niemela
    Abstract:

    Wood ants (Formica Rufa group) are dominating ecosystem elements of the boreal region due to their wide and abundant occurrence. They collect and concentrate organic material from the surrounding forest floor by building large above-ground mounds. These mounds have higher temperature and lower water content than the surrounding forest floor. We studied how these peculiar environmental conditions affected mass loss and carbon (C), nitrogen (N), phosphorus (P) and potassium (K) mineralisation of organic matter in boreal Norway spruce (Picea abies L. Karst.)-dominated mixed forest stands of four different age classes (5-, 30-, 60-, and 100-year-old) situated in eastern Finland using the litter bag technique. Norway spruce needle litter was incubated in inhabited and abandoned wood ant mounds as well as on the surrounding forest floor. We expected decomposition to be extremely slow due to the dryness of the mounds. Mass losses inside inhabited mounds were lower compared to the surrounding forest floor (on average 30 vs 50% after 2 years) but not as low as we expected, which might be a result of ant and microbial activity in the mounds. Decomposition in the abandoned mounds proceeded similarly as on the forest floor. Nutrient mineralisation proceeded more slowly in the ant mounds than on the surrounding forest floor. Mineralisation occurred for all studied nutrients in the ant mounds, except for N, which net amount remained stable during the years of the experiment. When wood ant mounds are abandoned and their porous and dry structure is no longer maintained by the ants, their decomposition is accelerated, and nutrients may be available for uptake by plants, although the nutrient mineralisation seems still to remain lower compared to the surrounding forest floor. However, eventually the mound material will be decomposed and nutrients mineralised, thus providing a nutrient hot spot increasing the heterogeneity of forest floor nutrient availability.

  • Carbon, nitrogen and phosphorus dynamics of ant mounds (Formica Rufa group) in managed boreal forests of different successional stages
    Applied Soil Ecology, 2007
    Co-Authors: Jouni Kilpelainen, Anita C Risch, Timo Domisch, Mizue Ohashi, Leena Finer, Seppo Neuvonen, Pekka Niemela, Liselotte Sundström
    Abstract:

    Wood ants (Formica Rufa group) are ubiquitous in European boreal forests and their large long-lived mound nests, which mainly consist of forest litter and resin, accumulate carbon (C) and nutrients. The C and nutrient dynamics of wood ant mounds in response to forest succession have received minor attention in boreal forests. We aimed to study whether the C, nitrogen (N) and phosphorus (P) concentrations and the bulk density of ant mounds differ from those of the surrounding forest soil, to estimate the C, N and P pools in ant mounds, and to test whether the concentrations and pools change with forest age. Norway spruce (Picea abies (L.) Karst.) stands on medium-fertile sites in 5-, 30-, 60- and 100-year stand age classes were studied in eastern Finland. Carbon and P concentrations in the above-ground mound material were higher than those in the surrounding organic layer. The C, N and extractable P concentrations were higher in the soil under the ant mounds than in the surrounding mineral soil (0–21 cm). The low bulk densities in the ant mounds and the soil below them could be a result of the porous structure of ant mounds and the soil-mixing activities of the ants. The C/N ratios were higher in the mounds than in the organic layer. Carbon concentrations in the ant mounds increased slightly with stand age. Carbon, N and P pools in the ant mounds increased considerably with stand age. Carbon, N and P pools in ant mounds were

Liselotte Sundström - One of the best experts on this subject based on the ideXlab platform.

  • the effect of stand age on co2 efflux from wood ant Formica Rufa group mounds in boreal forests
    Soil Biology & Biochemistry, 2012
    Co-Authors: Mizue Ohashi, Anita C Risch, Martin F Jurgensen, Timo Domisch, Leena Finer, Jouni Kilpelainen, Liselotte Sundström, Pekka Niemela
    Abstract:

    Abstract Recent studies suggest that wood ants ( Formica Rufa group) mounds are point sources of carbon dioxide (CO 2 ), which increase the heterogeneity of soil carbon (C) emissions in forest ecosystems. However, little is known about the impact of anthropogenic activities, such as logging and subsequent forest succession, on these fluxes. In this study, we measured the CO 2 efflux and temperature of wood ant mounds and the surrounding forest floor in managed Finnish boreal forests of different ages (5, 30, 60, and 100 years old) to assess how the effluxes vary with stand age. We conducted efflux measurements from the mounds and the surrounding forest floor throughout the ants' active season (May–September) and during the onset of hibernation (October). The annual CO 2 efflux was then estimated using mound or forest floor temperatures, which were measured for one year. The average annual CO 2 efflux from the ant mounds was 10.2 (±5.8 SD) kg m −2  year −1 , increasing from 3.9 (±0.3 SD) kg m −2  year −1 in the 5 year-old stands to 14.3 (±3.0 SD) kg m −2  year −1 in the 100 year-old stands. Temperatures was significantly higher in the ant mounds than in the forest floor, and the average temperature difference between mounds and forest floor increased with stand age, being the lowest in the 5 year-old (4.1 (±3.1 SD) °C) and highest in the 100 year-old stands (10.3 (±5.2 SD) °C). There were no statistical differences in the mound CO 2 efflux per volume among forest age classes, suggesting higher ant CO 2 efflux in the older stands likely come from larger ant populations in the bigger mounts. The different mound temperature regimes among stand age classes indicates that the activity of wood ants changes with forest succession, particularly after clear-cutting, which alters CO 2 efflux from the mounds. The impact of ant mounds on total CO 2 efflux from the soil, estimated from mound area and volume, respectively, increased with forest age, from 0.05 (±0.05 SD) % to 0.31 (±0.18 SD) % and from 0.05 (±0.06 SD) % to 0.90% (±1.11 SD).

  • does the mutualism between wood ants Formica Rufa group and cinara aphids affect norway spruce growth
    Forest Ecology and Management, 2009
    Co-Authors: Jouni Kilpelainen, Anita C Risch, Martin F Jurgensen, Timo Domisch, Mizue Ohashi, Leena Finer, Seppo Neuvonen, Pekka Niemela, Liselotte Sundström
    Abstract:

    Abstract Ant–aphid mutualisms, in which ants tend aphids, which in turn provide honeydew to the ants, are widespread and have been shown to affect plant growth. In boreal forests the effect of ant–aphid mutualism on tree growth can vary with stand age, because forest clear-cutting harms the ecologically most dominant ant partner in such mutualisms, wood ants (Formica Rufa group). We studied whether the mutualism between wood ants and Cinara aphids affects the growth of boreal Norway spruces (Picea abies L. Karst.) in stands of different ages. In boreal forests, conifers, unlike deciduous trees, have only few defoliating insects, and therefore we expected the growth loss of conifers due to sap sucking by aphids not to be compensated by reduced insect herbivory due to predation by wood ants. The study was conducted in medium-fertile spruce-dominated stands in eastern Finland. We used stands of four different age classes (5, 30, 60 and 100 years) and selected ten spruces heavily visited and ten spruces lightly visited by ants around five medium-sized ant mounds in each stand age class. The access of ants was blocked on half of the trees in both groups. In the 5-year-old stands, the mean annual height growth of individual heavily visited seedlings was 16.3% greater than in the ones where ant traffic was blocked, but this difference was not significant. In the 30-year-old stands, the mean annual radial growth of the heavily visited spruces was 7.3% smaller than in trees where ant traffic was blocked, and this difference was significant. The mutualism had no significant effect on the radial growth in the 60- and 100-year-old stands. In the 60-year-old stands, however, the spruces that were visited heavily prior to the beginning of the study grew significantly less relative to their past growth than the initially lightly visited trees during the study. This suggests that the ant–aphid mutualism may have long-term effects on tree growth. The ant–aphid mutualism had no significant effect on the growth at the stand level. The results indicate that ant–aphid mutualism can have a significant effect on the growth of individual spruces, but the effect is negligible at ecosystem level.

  • decomposition of organic matter and nutrient mineralisation in wood ant Formica Rufa group mounds in boreal coniferous forests of different age
    Biology and Fertility of Soils, 2008
    Co-Authors: Timo Domisch, Anita C Risch, Mizue Ohashi, Leena Finer, Jouni Kilpelainen, Liselotte Sundström, Pekka Niemela
    Abstract:

    Wood ants (Formica Rufa group) are dominating ecosystem elements of the boreal region due to their wide and abundant occurrence. They collect and concentrate organic material from the surrounding forest floor by building large above-ground mounds. These mounds have higher temperature and lower water content than the surrounding forest floor. We studied how these peculiar environmental conditions affected mass loss and carbon (C), nitrogen (N), phosphorus (P) and potassium (K) mineralisation of organic matter in boreal Norway spruce (Picea abies L. Karst.)-dominated mixed forest stands of four different age classes (5-, 30-, 60-, and 100-year-old) situated in eastern Finland using the litter bag technique. Norway spruce needle litter was incubated in inhabited and abandoned wood ant mounds as well as on the surrounding forest floor. We expected decomposition to be extremely slow due to the dryness of the mounds. Mass losses inside inhabited mounds were lower compared to the surrounding forest floor (on average 30 vs 50% after 2 years) but not as low as we expected, which might be a result of ant and microbial activity in the mounds. Decomposition in the abandoned mounds proceeded similarly as on the forest floor. Nutrient mineralisation proceeded more slowly in the ant mounds than on the surrounding forest floor. Mineralisation occurred for all studied nutrients in the ant mounds, except for N, which net amount remained stable during the years of the experiment. When wood ant mounds are abandoned and their porous and dry structure is no longer maintained by the ants, their decomposition is accelerated, and nutrients may be available for uptake by plants, although the nutrient mineralisation seems still to remain lower compared to the surrounding forest floor. However, eventually the mound material will be decomposed and nutrients mineralised, thus providing a nutrient hot spot increasing the heterogeneity of forest floor nutrient availability.

  • Carbon, nitrogen and phosphorus dynamics of ant mounds (Formica Rufa group) in managed boreal forests of different successional stages
    Applied Soil Ecology, 2007
    Co-Authors: Jouni Kilpelainen, Anita C Risch, Timo Domisch, Mizue Ohashi, Leena Finer, Seppo Neuvonen, Pekka Niemela, Liselotte Sundström
    Abstract:

    Wood ants (Formica Rufa group) are ubiquitous in European boreal forests and their large long-lived mound nests, which mainly consist of forest litter and resin, accumulate carbon (C) and nutrients. The C and nutrient dynamics of wood ant mounds in response to forest succession have received minor attention in boreal forests. We aimed to study whether the C, nitrogen (N) and phosphorus (P) concentrations and the bulk density of ant mounds differ from those of the surrounding forest soil, to estimate the C, N and P pools in ant mounds, and to test whether the concentrations and pools change with forest age. Norway spruce (Picea abies (L.) Karst.) stands on medium-fertile sites in 5-, 30-, 60- and 100-year stand age classes were studied in eastern Finland. Carbon and P concentrations in the above-ground mound material were higher than those in the surrounding organic layer. The C, N and extractable P concentrations were higher in the soil under the ant mounds than in the surrounding mineral soil (0–21 cm). The low bulk densities in the ant mounds and the soil below them could be a result of the porous structure of ant mounds and the soil-mixing activities of the ants. The C/N ratios were higher in the mounds than in the organic layer. Carbon concentrations in the ant mounds increased slightly with stand age. Carbon, N and P pools in the ant mounds increased considerably with stand age. Carbon, N and P pools in ant mounds were

  • carbon nitrogen and phosphorus dynamics of ant mounds Formica Rufa group in managed boreal forests of different successional stages
    Applied Soil Ecology, 2007
    Co-Authors: Jouni Kilpelainen, Anita C Risch, Timo Domisch, Mizue Ohashi, Leena Finer, Seppo Neuvonen, Pekka Niemela, Liselotte Sundström
    Abstract:

    Wood ants (Formica Rufa group) are ubiquitous in European boreal forests and their large long-lived mound nests, which mainly consist of forest litter and resin, accumulate carbon (C) and nutrients. The C and nutrient dynamics of wood ant mounds in response to forest succession have received minor attention in boreal forests. We aimed to study whether the C, nitrogen (N) and phosphorus (P) concentrations and the bulk density of ant mounds differ from those of the surrounding forest soil, to estimate the C, N and P pools in ant mounds, and to test whether the concentrations and pools change with forest age. Norway spruce (Picea abies (L.) Karst.) stands on medium-fertile sites in 5-, 30-, 60- and 100-year stand age classes were studied in eastern Finland. Carbon and P concentrations in the above-ground mound material were higher than those in the surrounding organic layer. The C, N and extractable P concentrations were higher in the soil under the ant mounds than in the surrounding mineral soil (0–21 cm). The low bulk densities in the ant mounds and the soil below them could be a result of the porous structure of ant mounds and the soil-mixing activities of the ants. The C/N ratios were higher in the mounds than in the organic layer. Carbon concentrations in the ant mounds increased slightly with stand age. Carbon, N and P pools in the ant mounds increased considerably with stand age. Carbon, N and P pools in ant mounds were <1% of those in the surrounding forest soil. Nevertheless, the above- and belowground parts of the ant mounds contained more C, N and P per sampled area than the surrounding forest soil. Wood ants therefore increase the spatial heterogeneity in C and nutrient distribution at the ecosystem level.