Spatial variation in herbivory by forest canopy arthropods along an elevation gradient

• Published in: Environmental entomology Vol. 26; no. 6
• Main Authors: Reynolds, B.C. (University of Georgia, Athens.), Crossley, D.A. Jr
• Format: Journal Article
• Language: English
• Published: 01.12.1997
• Subjects: ACER RUBRUM; ALTITUD; ALTITUDE; ARTHROPOD FEEDING GUILDS; ARTHROPODA; BOSQUES; CANOPY; CAROLINA DEL NORTE; CAROLINE DU NORD; COMMUNITY ECOLOGY; COUVERT; CUBIERTA DE COPAS; DECIDUOUS PLANTS; DENSIDAD DE LA POBLACION; DENSITE DE POPULATION; ECOLOGIA; ECOLOGIE; ECOLOGY; FORESTS; FORET; HERBIVORE; HERBIVORES; HERBIVOROS; LEAF AREA; NORTH CAROLINA; PLANTAS DECIDUAS; PLANTE A FEUILLES CADUQUES; POPULATION DENSITY; QUERCUS RUBRA; REMOVAL; SUPERFICIE FOLIAR; SURFACE FOLIAIRE
• ISSN: 0046-225X; 1938-2936
• DOI: 10.1093/ee/26.6.1232

Spatial variation has recently been recognized as an important component in ecological processes. Elevation differences are an obvious example of spatial variation, but little is known about the influence of elevation on canopy insect herbivory. We examined elevation effects on canopy insect herbivory in an eastern deciduous forest. Percentage leaf area removed and canopy arthropod guild structure were measured at 3 sites along an elevation gradient in the southern Appalachians. Acer rubrum L. was sampled at all sites; Quercus rubra L. at the lowest and highest sites. Upper and lower canopies of A. rubrum were sampled at the highest site. Canopy walkways were used in most sampling. Our 1st hypothesis was that percentage leaf area removed would decrease as elevation increased because of decreases in temperature. Percentage leaf area removed decreased significantly for both tree species as elevation increased. We also hypothesized that percentage leaf area removed would be greater in the lower canopy, because shade leaves are reportedly more palatable to herbivores. Percentage leaf area removed was significantly greater in the lower canopy compared with the upper canopy of A. rubrum. Our 3rd hypothesis was that arthropod guild structure would vary along the elevation gradient because of environmental differences reflecting elevation differences. Arthropod guild structure was significantly different for A. rubrum at all sites but similar for Q. rubra. Spatial variation, in terms of elevation differences, was shown to have a significant effect on forest insect herbivory and arthropod guild structure