The influence of weather conditions on the activity of high-arctic arthropods inferred from long-term observations

Toke T Høye,Mads C Forchhammer

doi:10.1186/1472-6785-8-8

Abstract

BackgroundClimate change is particularly pronounced in the High Arctic and a better understanding of the repercussions on ecological processes like herbivory, predation and pollination is needed. Arthropods play an important role in the high-arctic ecosystem and this role is determined by their density and activity. However, density and activity may be sensitive to separate components of climate. Earlier emergence due to advanced timing of snowmelt following climate change may expose adult arthropods to unchanged temperatures but higher levels of radiation. The capture rate of arthropods in passive open traps like pitfall trap integrates density and activity and, therefore, serves as a proxy of the magnitude of such arthropod-related ecological processes. We used arthropod pitfall trapping data and weather data from 10 seasons in high-arctic Greenland to identify climatic effects on the activity pattern of nine arthropod taxa.ResultsWe were able to statistically separate the variation in capture rates into a non-linear component of capture date (density) and a linear component of weather (activity). The non-linear proxy of density always accounted for more of the variation than the linear component of weather. After accounting for the seasonal phenological development, the most important weather variable influencing the capture rate of flying arthropods was temperature, while surface-dwelling species were principally influenced by solar radiation.ConclusionConsistent with previous findings, air temperature best explained variation in the activity level of flying insects. An advancement of the phenology in this group due to earlier snowmelt will make individuals appear earlier in the season, but parallel temperature increases could mean that individuals are exposed to similar temperatures. Hence, the effect of climatic changes on the activity pattern in this group may be unchanged. In contrast, we found that solar radiation is a better proxy of activity levels than air temperature in surface-dwelling arthropods. An advancement of the phenology may expose surface-dwelling arthropods to higher levels of solar radiation, which suggest that their locomotory performance is enhanced and their contribution to ecological processes is increased.

Highlights

Climate change is pronounced in the High Arctic and a better understanding of the repercussions on ecological processes like herbivory, predation and pollination is needed
The generalized additive models (GAM) models identified the weather variable that resulted in the lowest residual deviance of models for each species group in each year in each plot (Table 1)
Ambient air temperature was best at explaining variation in capture numbers followed by solar radiation which was important in models of surface-dwelling taxa

Summary

Introduction

Climate change is pronounced in the High Arctic and a better understanding of the repercussions on ecological processes like herbivory, predation and pollination is needed. The earth is undergoing climatic changes and the model predictions for the high-arctic climate are dramatic [1] This underscores the urgency for achieving a better understanding of how climate affects ecological processes like herbivory, predation and pollination [2]. We have previously shown that high-arctic arthropods have advanced their emergence phenology in recent years in response to earlier timing of snowmelt [12] This shift in phenology may expose arthropods to a time of the season with different weather conditions and may affect their level of activity

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