Urbanization forces tiger snakes to inbreed

Tiger snake populations are suffering from urbanization, according to a new study from Curtin University in Australia. The researchers found that human development has left tiger snakes isolated in small populations that are more likely to inbreed. 

“Urbanization alters landscapes, introduces wildlife to novel stressors, and fragments habitats into remnant ‘islands,'” wrote the study authors. “Within these islands, isolated wildlife populations can experience genetic drift and subsequently suffer from inbreeding depression and reduced adaptive potential.”

The researchers examined patterns of genomic diversity and population structure among tiger snakes in and around the city of Perth.

“Tiger snake populations north of the Perth rivers at Herdsman Lake, Lake Joondalup and Yanchep National Park were found to lack genetic diversity while wetlands south of the Swan/Canning River system were home to the most genetically diverse populations of snakes, meaning they were less prone to inbreeding,” explained study lead author and PhD candidate Damian Lettoof.

“If tiger snake populations isolated by urbanization are suffering from lower genetic diversity, they can lose their ability to adapt in order to survive ever-changing environments due to development, pollution and climate change.”

“This is probably due to them being unable to cross unsuitable habitat such as large rivers, arid areas, and now the urban landscape.”

Tiger snakes are an important part of their wetland habitats and are indicators of environment health overall. 

“Tiger snakes are near the top of their food chain and have very specific habitat requirements, meaning a wetland with a snake population lacking in genetic diversity was indicative of an ecosystem that was not healthy or well-functioning,” said Lettoof.

“This means many other small species – such as frogs, lizards and fish – living in these wetlands that are increasingly being ‘cut off’ by urban development may also be suffering and at risk of population decline and even extinction.”

The research has important implications for conservation as well as what future expansion of urbanization may look like. “Our research suggests larger wetlands being encroached upon by urbanization such as those on the Swan coastal plain need to be managed as ‘islands’ of urban biodiversity in order to protect the animal communities inhabiting them.”

The study is published in the journal PLOS ONE.

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By Zach Fitzner, Earth.com Staff Writer