Nature and science
Testing the ponds people built
Documented history and research · Sources compared
A comparison of natural ponds, excavated ponds and stormwater basins found that providing water did not make every wetland equivalent.
Three kinds of pond
With federal funding awarded in 2012 and 2013, Commission scientists mapped 5,850 natural ponds, excavated ponds and stormwater basins. Excavated ponds intercept groundwater; stormwater basins receive runoff. That distinction gave researchers a way to ask whether similar-looking water bodies offered equivalent ecological conditions in different surrounding landscapes. Commission, Natural and Created Wetlands Study.
The larger study also assessed potential future development and vehicle damage. Natural ponds were generally less exposed to projected development because many lay in protected areas. Protection from surrounding construction, however, was a separate question from the quality of water or the presence of disease within a particular pond. Commission, Natural and Created Wetlands Study.
Chemicals and pathogens did not follow one simple pattern
A cooperating USGS team sampled 24 wetlands during 2014–2016. Its 2018 report found more pesticides and greater total pesticide concentrations in stormwater basins than in natural or excavated ponds. Reference wetlands also had fewer pesticides than degraded wetlands. These comparisons linked measured contamination with wetland type and surrounding land use. Smalling and colleagues, USGS report (2018).
The pathogen results were less easily divided into good and bad pond categories. Ranavirus appeared in larvae from four wetlands, including a reference natural pond. The chytrid fungus Bd was detected in animals from all three wetland types, although detection probability was low. Those findings do not establish that creating a basin caused disease, or that a single negative sample proved a pond pathogen-free. Smalling and colleagues, USGS report (2018).
Sources and research limits
- Commission, Natural and Created Wetlands Study — Official project background and summary inspected.
- Smalling and colleagues, USGS report (2018) — Complete institutional abstract read and linked 24-site data-release description checked.
No raw laboratory records were reanalyzed. Association between land use and contamination is not proof that a particular pesticide caused an infection or population decline.