Invasive Plants Hijacking Toad Abodes?

Canada, the land of beautiful landscapes, is home to many species of North American plants and animals. One species of toads found in Canada, the Fowler’s toad (Anaxyrus fowleri), are endangered under Canadian legislation as there are only three small populations of these toads found on the northern part of Lake Erie.  These toads face many obstacles to their survival: diseases, climate change, and water pollution.

However, a new study from researchers of McGill University finds that these toads are now under attack from another threat, the common reed plant!

Common ReedThe common reed (Phragmites australis) used to just occupy one hectare for a long time, until an invasive strain of the reeds emerged around 1995. Then, just like spider twerking took over the interwebs, the common reed started invading the marshes where the Fowler’s toads breed.

In order to calculate the amount of toads present, researchers Daniel Greenberg and David Green, caught all the adult male toads during each breeding season from 23 years from 1989-2011. They found that the Fowler’s toad populations were pretty steady for most of these years until about 2002, when there was a clear gradual decline. What might have caused this you ask? It was none other than the common reed.

The common reed started moving fast, conquering the marshes at about 11.1% per year. Moreover, the lower water levels that these marshes of Lake Erie have been experiencing only helped this quick invasion as the plants like their water low. By 2010, the common reed had spread to 15% of the total marsh area aka an alarming 85.4 hectares compared to the <1 ha that the reed occupied only 20 years before.  As these toads are being pushed out of their breeding habitats, the area that is left for them can only support so many toads. In 1989, at the beginning of this study, the marshland could hold 176 male toads. Since then, so much of this marshland has been lost to the common reed that the toad breeding area can hold eight less toads a year.

Luckily for the toads, there is hope for their success regardless of all these hardships. Fowler's ToadThese toads are known for being pretty tough and can put up with a lot of problems in their environment. Moreover, even with the little breeding habitat that they have, they can still put out a lot of little tadpoles. The Fowler’s toads can reproduce with large clutch sizes of around 2,000 to 10,000 eggs!

Also, the researchers came up with ways to help conserve the Fowler’s toad and keep them from dying out. First, in order to save these toads temporary artificial breeding ponds can be created in order to give these toads more space to recover their numbers. Moreover, conservationists will have to develop strategies to effectively restrict these reeds from spreading any further into the marshes

Furthermore, the authors proposed different solutions to combat the decline of the Fowler’s toad and alleviate the stress on the toad populations of Canada. These solutions include creating temporary artificial breeding ponds to foster an environment for the populations to grow, developing strategies to effectively restrict the further spread of these common reeds into the marshes of the northern shore of Lake Erie, and restoring the already invaded areas.

The decline of the Fowler’s toads is an important conservation issue in Canada. If efforts aren’t made to save these cute little toads, they could soon be extinct from the Canadian frontiers.

References

GREENBERG, D. A., & GREEN, D. M. (2013). Effects of an Invasive Plant on Population Dynamics in Toads. Conservation Biology.

Photo Credit

Common Reed

” Phragmites australis” by  Matt Lavin is licensed under CC BY 2.0

Fowler’s Toad

” Fowler’s Toad” by  Sara Viernum is licensed under CC BY-NC-ND 2.0

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This entry was posted in Conservation Biology Posts, Conservation Blogs 2012-2013. Bookmark the permalink.

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