For at least ten years, scientists have been noting changes in wild koala populations that appear to be linked to the quality of their only food source: eucalyptus. Increases in CO2 levels are causing eucalyptus to grow faster. But faster is not always better. This rapid growth produces foliage that is poorer in nutrients and higher in toxic tannins. Koalas have evolved to be able to process these compounds within certain ranges. These shifts in nutritional content are leading to cases of malnutrition in the animals, and secondarily to higher mortality due to predation and highway collisions as the animals seek out new food sources. Nearly ten years ago, the International Union for the Conservation of Nature published concerns over this phenomenon in 2009, and subsequent studies are underscoring the gravity of these circumstances. There are troublesome implications for many other plant–animal relationships including humans and our heavy global reliance on a small number of plant species. Recent studies suggest that rising CO2 levels are leading to nutritional changes in rice and wheat. —Sandy Masuo

Read more about climate change and nutritional changes in rice and wheat:

https://www.npr.org/sections/thesalt/2018/06/19/616098095/as-carbon-dioxide-levels-rise-major-crops-are-losing-nutrients

For more information about climate change and koalas:

https://phys.org/news/2016-02-climate-koalas-diet-inedible.html

https://cmsdata.iucn.org/downloads/fact_sheet_red_list_koala_v2.pdf