High marks for soil life in Dutch gardens
The woodlouse is the most common soil animal in Dutch gardens. That is the outcome of the first soil animal count in the Netherlands. According to the NIOO-led probe, most Dutch gardens have a more than averagely healthy soil life.
They may be less colourful than birds or butterflies - and some have a serious image problem - but more than 10,000 soil animals were counted on 'Soil Animal Day', 4 October.
That means hundreds of Dutch families and households went out into their backyard or to their local park and recorded what kinds of soil animals they saw there.
Results
| ANIMAL | % OF GARDENS |
| Woodlouse | 94 |
| Spider | 93 |
| Earthworm | 91 |
| Snail | 85 |
| Slug | 82 |
| Ant | 72 |
| Centipede | 61 |
| Beetle | 49 |
| Millipede | 39 |
| Mole | 7 |
The organisers of the count - the Netherlands Institute of Ecology and the Centre for Soil Ecology - then took a week to analyse the results.
They looked at both the variety and distribution of the ten main groups of soil animals, and the overall health of the soil community in different types of gardens.
After woodlice, spiders and earthworms turned out to be the most frequently reported soil animals, while beetles and millipedes were significantly less common and actual sightings of moles were quite rare.
Overall though, said NIOO-researcher Gerard Korthals, "most of the main groups of soil animals were sighted quite frequently. That means gardens can indeed play an important role in maintaining a healthy urban nature."
Gardens
People who participated in the count were asked to describe their location: was it a green or partially green garden, a paved garden, a balcony or did they have to go out to a public garden or park?
The overall mark for the state of health of Dutch gardens, based on both the number of soil animals reported and their variety across all types of gardens, ended up being an impressive nine out of ten.
| TYPE | MARK |
| Green garden | 9.1 |
| Public garden/park | 9.0 |
| Semi-green garden | 8.8 |
| Paved garden | 8.5 |
| Green roof | 7.6 |
| Balcony | 7.0 |
And while paved gardens and balconies did not score quite as high as green gardens - the numbers per group were often significantly lower - even those types did surprisingly well.
Vital
A number of annual and other animal counts are held in the Netherlands, but this was the first time the public could contribute to charting the overall health of the soil community.
Healthy soil life is vital to having healthy soil. And without healthy soil, there is no natural clean water, not enough food to eat and no materials to manufacture clothes, to name just a few things.
"Just imagine: a single handful of soil contains more living organisms than there are people on the entire planet!"
Rare
Finally, NIOO-researcher Gerard Korthals says he's looking forward to looking further into the distribution of the rarest species reported during the soil animal count.
In addition to the ten main groups, participants could indicate if they had identified any specific species - e.g. wolf-spiders or harvestmen, in the case of spiders.
The rarest overall species to be reported during the soil animal count was the Clausilia, a small, air-breathing land snail with an elongated shell.
Out of the more than 10,000 soil animals reported during the probe, only eleven were identified as Clausilia.
- Results, maps & graphs: http://bodemdierendag.nioo.knaw.nl (page in Dutch)
- Backgrounds, fun facts and pictures: http://bodemdierendag.nl (page in Dutch)
