Study: Flora not flourishing in tropics

Canadian researchers say they’ve determined extinction risks for plants growing in the Earth’s tropical regions are higher than previously thought.

University of Calgary Assistant Professors Jana and Steven Vamosi studied plant extinction risks in areas close to the equator.

The tropics contain many ancient species of plants, leading many to consider tropical species as less susceptible to extinction, said Steven Vamosi. But our study indicates that quite the opposite is, in fact, the case. The extinction risk for plants is high in countries close to the equator and even higher on islands, even after we take into account factors related to human activities and their use of the natural resources.

The study focused on the number of plant species at risk, looking at human factors such as population density and deforestation.

Our findings differ from previous ones in that factors tightly linked to human activity were not particularly important in determining how many plant species were threatened with extinction, he said. Instead, the most important factor seemed to be simply latitude. So, extinction dynamics may be very different between plant and animal species. Plant species near the equator may persist at naturally low population sizes or have small ranges, making them intrinsically more susceptible to a given amount of disturbance.

The research is reported in the online journal PLoS One.