Use of Shifting Microclimatic Mosaics by Arthropods on Exposed Tree Trunks

Abstract

Abstract This study focused on two questions relevant to ecophysiology: Do distributions of animal species track shifting microclimatic mosaics under field conditions? Do distributions on different levels of spatial resolution (different “scales”) consistently modify a species’ access to heat or humidity? I counted the arthropods on the bark of exposed tree trunks in northern Germany with a 10× lens and investigated how the dominant species (collembolans, psocopterans, isopods, a linyphiid spider, and an oribatid mite) used climatic patterns at various scales. These included mesoclimatic patterns and shifting microclimatic patterns such as microrelief, trunk faces, and trunk/mesoclimate differences. Bias owing to changing frequency of microhabitats, or to redistributions of animals between microhabitats was avoided. I also investigated the effects of climatic patterns on heat and humidity levels at the bark surface. The distributions of all species, except the psocopterans, similarly tracked shifting micr...