The belowground foodweb holds a big part of the associated biodiversity in forest ecosystems and plays a major role in litter decomposition and nutrient turnover. So far important interactions between diversity and composition of above- and belowground foodwebs have been observed, however, without being conclusive on the effects of tree species diversity on the belowground foodweb. The response of earthworms as important functional group in the soil ecosystem is assessed. The earthworm sampling records the abundance, biomass and species diversity of earthworms in each focal region. All (30 x 30) m2 plots are divided in nine (10 x 10) m2 subplots. In every plot, earthworms were sampled in the middle subplot. First (if present), a central litter sample (25x25cm) is taken followed by the 'mustard extraction method' over an area of 0,5 m² (0.5x1m) and a final soil sample (25x25x20cm) (length, width, depth) in the middle of this location. Litter and soil samples were taken to the lab for further handsorting, whereby the pit left after sampling was levelled off with surrounding soil. Sampled earthworms are stored in 70% ethanol solution.

For every plot of the focal region, plots (30 x 30) m2 are divided in nine (10 x 10) m2 subplots. In every plot, earthworms were sampled in the middle subplot. In principle, within every middle subplot, the samples are taken randomly, but samples are not taken close to tree stems. First (if present), a central litter sample (25x25cm) is taken followed by the 'mustard extraction method' over an area of 0,5 m² (0.5x1m) and a final soil sample (25x25x20cm) (length, width, depth) in the middle of this location. When no litter is present, no litter sample could be taken and only a mustard extraction and soil sample is carried out. Litter and soil samples were taken to the lab for further handsorting, whereby the pit left after sampling was levelled off with surrounding soil. Sampled earthworms are stored in 70% ethanol solution.

Alto Tajo Natural Park, Spain

Autumn 2012

Earthworms

In some sites additional hand catches are performed, next to the standardized sampling. Hand catches are done within a distance of maximum 1m away from the focal earthworm sampling area. These hand catches are performed while conducting other measurements and samplings and as a consequence can only function as extra background information. See file attached to this dataset.