Combined effects of chemical and temperature stress on Chironomus riparius populations with differing genetic variability

Abstract

Exposure to pollutants under multiple environmental stressors (e.g., climate change and global warming) and the genetic diversity of populations are suspected to have serious impacts on populations and ecosystems but have only rarely been analysed. In the present study, we investigated the effects of the biocide tributyltin (TBT) within a temperature gradient (17, 20 and 23°C) on life history parameters of a genetically diverse (GEN+) and a highly inbred population (GEN−) of the midge Chironomus riparius. While endpoints, mortality and reproduction parameters were considered, the population growth rate as an integrative endpoint was determined. We found severe effects for GEN−, indicating that populations with lower genetic diversity are more endangered by combined stressors such as increasing temperature and chemical pollution compared to genetically diverse populations.

Keywords:

• Environmental stressors
• climate change
• tributyltin
• Chironomidae
• life history parameters
• genetic impoverishment
• extinction risk

Acknowledgments

We would like to thank the staff of the working groups Ecology and Evolution and Aquatic Ecotoxicology of the Goethe University Frankfurt am Main for technical assistance. This research has been supported by the programme “Environmental Quality and its Security and Sustainment” (BW-Plus) with funding of the state of Baden-Württemberg (project number BWR 22018) and by the LOEWE Research Centre Biodiversity and Climate Frankfurt (BiK^F).

Notes

^a (control 20°C, P < 0.001);

^b (TBT 20°C, P < 0.001);

^c (corresponding control, P < 0.05, and 23°C TBT, P < 0.001);

^d (corresponding control, P < 0.05);

^e (TBT 20°C, P < 0.05),

^f (control 20°C, P < 0.01).