Rapid range shifts in African Anopheles mosquitoes over the last century

Abstract

AbstractAnopheles mosquitoes are the vector of malaria and several neglected tropical diseases, such as lymphatic filariasis and O’nyong’nyong fever. Like many species, mosquitoes are expected to track warming temperatures in a changing climate, possibly introducing disease into previously protected higher-latitude and higher-elevation communities. Tracking range shifts is fundamental for forecasting disease risk, but has proven challenging to do in real-time. Here, we use historical data to trace those shifts in Anopheles for the first time. We test for range shifts using a new comprehensive dataset of Anopheles occurrences in sub-Saharan Africa, with over 500,000 species-locality pair records spanning 1898 to 2016. We propose a simple regression-based method of measuring range shifts in larger datasets, which identifies a more coherent signal in anopheline range shifts than the Mann-Whitney method popular in ecology. We estimate range-shifting species gained 1.56 meters of elevation annually, and moved southward 6.28 km per year in their outer range limits, a full order of magnitude faster than some “rapid” shifts observed in the literature. We expect these results to have major implications for malaria control work in sub-Saharan Africa, and for our broader picture of vector responses to climate change.