Newts as ecological warning signs: what they reveal about wetland health

During the breeding season, researchers surveyed the abundance of smooth newts (Lissotriton vulgaris) at 32 wetland sites around Lake Balaton. They also examined how the extent of surrounding natural and anthropogenically modified land – such as wetland size, forested and grassland areas, agricultural and urban land use, and proximity to roads and railways – affects newt abundance. The study was conducted at three spatial scales (within 250, 500 and 1000 metres), enabling a more precise assessment of the relative influence of different landscape features. 

The results show that natural wetland habitats – such as ponds, marshes, periodically flooded grasslands and shrubs – play a key role in supporting species persistence, particularly when located within 500 metres of breeding sites. These habitats are likely to facilitate connectivity between local populations. In contrast, agricultural areas – especially those within 250 metres of breeding sites – as well as roads and railways, were found to negatively affect newt abundance. 

The study offers several possible explanations for these findings. Roads and railways, on the one hand, act as physical barriers during seasonal migrations and significantly increase the risk of road mortality, particularly during the breeding season, when adult individuals move from terrestrial to aquatic habitats. On the other hand, such linear infrastructure can alter local microclimatic conditions, elevate noise and light pollution, and contribute to water contamination via surface runoff – all of which may adversely impact newt survival. 

The smooth newt is not only a remarkable species but also a sensitive indicator – its presence or absence can reveal a great deal about the ecological condition of wetland habitats, the researchers emphasise. Their findings carry an important message: the protection of natural habitats and the maintenance of ecological corridors are essential not only for this species, but also for conserving biodiversity more broadly – particularly in urbanised landscapes such as the Lake Balaton region.