Humans are causing a massive animal extinction without precedent in 65 million years.

2016-12-23T18:52:10

SignificanceArthropods, invertebrates including insects that have external skeletons, are declining at an alarming rate. While the tropics harbor the majority of arthropod species, little is known about trends in their abundance. We compared arthropod biomass in Puerto Rico’s Luquillo rainforest with data taken during the 1970s and found that biomass had fallen 10 to 60 times. Our analyses revealed synchronous declines in the lizards, frogs, and birds that eat arthropods. Over the past 30 years, forest temperatures have risen 2.0 °C, and our study indicates that climate warming is the driving force behind the collapse of the forest’s food web. If supported by further research, the impact of climate change on tropical ecosystems may be much greater than currently anticipated.

34 Aim 35Evaluating the relative roles of biological traits and environmental factors that predispose 36 species to an elevated risk of extinction is of fundamental importance to macroecology. Results 54Range size was the most important predictor of extinction risk, reflecting the high frequency 55 of reptiles assessed under range-based IUCN criteria. Habitat specialists occupying accessible 56 ranges were at a greater risk of extinction: although these factors never contributed more than 57 10% to the variance in extinction risk, they showed significant interactions with range size. 58Predictive power of our global models ranged between 23 and 29%. The general overall 59 pattern remained the same among geographic, taxonomic and threat-specific data subsets. Main conclusions 62Proactive conservation requires shortcuts to identify species at high risk of extinction.

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