The world's oldest man-made biological experiment

Biological experiments are often short-lived due to logistical or resource-related challenges, and short-term observations are extrapolated to make long-term predictions. However, the effects of experimental treatments on biological communities and processes take time to develop. Consequently, the robustness of conclusions drawn from observations increases with the duration of the experiment. As a striking real-world example and scattered throughout central Laos, thousands of large stone jars have been left behind from ancient burial rituals. The most famous sites in the Xiengkhouang province are collectively referred to as the Plain of Jars. These jars form a massive biological experiment: for ~2000 years, rainwater has interacted with the geological origin of each jar to create unique yet replicated aquatic ecosystems influenced by different tree coverage. The layout of these jars, with clusters of up to several hundred jars separated by several kilometers, allows for controlled testi..., The data was collected during an initial assessment of environmental conditions in jar-based ecosystems on the Plain of Jars:
Five sites, that have been cleared of unexploded ordnance and are therefore now safely accessible, were selected to study the environmental conditions inside the jars. Each site has a different number of available jars, depending on the size of the site and the condition of the jars, as many are broken and therefore unable to hold water. Site 1 is exposed on the plateau, with only a few trees in the vicinity. Ten jars from three different groups (1, 2, and 4) were studied at this site. Sites 2, 3, 21, and 52 are located in the forest and surrounded by trees. We investigated 6 jars at site 2, 6 jars at site 3, and 15 jars at site 52, respectively. At Site 21, two jars were sampled. We present here data from the samplings in November 2022 and September 2023. At each site, jars were randomly selected during the first visit, but based on their ability to hold water, ..., # Data from: The world's oldest man-made biological experiment

Dataset DOI: [10.5061/dryad.7m0cfxq8w](https://doi.org/10.5061/dryad.7m0cfxq8w)

## Description of the data and file structure

### Files and variables

#### File: Käseetal_Ecography_The_world’s_oldest_man-made_biological_experiment.csv

**Description:** 

##### Variables

* Jar_name_adaptedfromShewanetal.2020: Jar names adapted from the Plain of Jars Archaeological Research Project (Shewan et al., 2020).\
*Reference:* Shewan, L., O'Reilly, D., Kemp, J., Tomko, M., Hardiman, R., Barnes, D., Michalewicz, A., Thompson, K., Fitzgerald, E., Garber, J. Turnbull, R. 2020. Plain of Jars Archaeological Research Project ([www.plain-of-jars.org](http://www.plain-of-jars.org)).
* Site: Official site names (see also Shewan et al., 2020).
* Sampling: Season of sampling: Dry season: November 2022, Wet season: September 2023
* Samplingtime: Sampling time (November 2022 or September 2023)
* Latitude / Longitude: GPS coordinates of each j...,