Driving factors and their interactions of carabid beetle distribution based on the geographical detector method

Abstract

The decline of insect diversity has received widespread attention as a serious ecosystem problem worldwide. Accurately learning the driving factors of insect decline is difficult because of the complex multitrophic and environmental interactions involved. The scientific interpretation of the factors driving insect distribution is essential to understanding biological systems and the effects of changed environment. Generally, insect distributions result from the interactions of different factors, therefore, understanding how multi-factor interactions effect of carabid distribution is beneficial. Carabid beetles are indicator species in the steppes of northwestern China. Previous studies have focused on the main driving factors of carabid beetle occurrence separately, ignoring the interactions between drivers. Using the Geographical Detector method, a new method of spatial statistics, the interactive influences of 15 variables on carabid beetle distribution were quantified at three steppes in the Ningxia Hui Autonomous region, of northwestern China. The results showed that carabid beetle distribution in the steppes was primarily driven by annual average precipitation (q=0.55). Among the interactions of factors, precipitation ∩ Altitude (q=0.719) was the strongest, followed by precipitation ∩ plant biomass (q=0.677 ), and precipitation ∩ pH value (q=0.677). The areas with the greatest risk of carabid beetle decline are the desert steppe and northern parts of the meadow steppe. This study shows that the Geographical Detector approach was successful for analyzing the driving forces of carabid beetle distribution. Our study also offers a new method for understanding the interactions between different drivers of other animal distributions more broadly.