Germany is currently (June 2013) experiencing some of the worst flooding in history. Our media discusses the need for insect repellent due to rises in mosquito populations. However, we hear less about detrimental effects of flooding on insects. In 1999, there was severe flooding on the Upper Rhine in Southwestern Germany. A ground-nesting bee, Andrena vaga, that was a target of conservation efforts had nests in regions with some of the most severe flooding. Data on the bee populations pre- and post-flooding clearly showed high mortality in the flooded areas.* The nests of the bees were flooded and most (or in some cases all) of the brood in monitored areas were killed. The flood not only killed the bees, but had negative impact on other species associated with the bees.
Conservation efforts for animals in areas prone to flooding need to consider infrequent events, such as 100 year floods, that can create disturbances. If flooding is increasing in frequency due to climate change, then conservation efforts may be inadequate to preserve the habitat necessary to sustain some species.
*Journal of Insect Conservation 8: 311–322, 2004.