Extreme weather threatens ecosystems

Hurricanes, torrential downpours and droughts will become more frequent with global warming, threatening species especially in bio-diverse ecosystems and tropical rainforests. Flora and fauna will become extinct at a rate 100-1,000 times higher than normal. Climate change has been deemed one of the main causes of species depletion. A team of theoretical biologists at Linkoping University in Sweden has studied how the dynamics of different types of ecosystems may be affected by significant environment fluctuation, the journal Ecology and Evolution reports. Linda Kaneryd, a doctoral student who led the study, explains: “Several previous studies of food web structures have suggested that species-rich ecosystems are often more robust than species-poor ecosystems. “However, at the onset of increased environmental fluctuations, such as extreme weather, we see that extreme species-rich ecosystems are the most vulnerable. “This entails a greater risk for so-called cascading extinction.” In a rainforest or on coral reef, there are a variety of species of primary producers such as green plants and algae. Since they are competitors, relatively few individuals of the same species exist, subjecting them to a greater risk of extinction should external conditions change. This could result in a depletion of food sources for a species of herbivores that, in turn, affects a predator at the top of the food chain. Biologists call this transformation a cascading extinction.