PARENT SESSION
Symposium 11: Digging Deeper or Scratching the Surface? Exploring Ecological Theories in Urban Soils.
Organized by: M Pavao-Zuckerman and L Byrne
Wednesday, August 4, 8:00 AM to 10:30 AM, Oregon Ballroom 203.

Disturbance and soil faunal community dynamics: Lessons from American and European cities.

Szlavecz, Katalin ^*,1, ¹ The Johns Hopkins University, Baltimore, MD, USA

ABSTRACT- Urbanization is portrayed as one of the leading causes of biodiversity loss due to habitat destruction and alteration. Moreover, cities have always been the hotspots of species introduction. As part of the Baltimore Ecosystem Study LTER project we have been assessing soil invertebrate fauna in urban and rural forests and lawns. Our data show that contrary to the general belief urban areas support important pools of biodiversity with new species to science or the regional fauna. However, a contributing factor to this biodiversity is the presence of non-native species. The significance of exotic soil fauna is strongly taxon-dependent. Percentage of non-native species varied between 0 % (Coleoptera: Silphidae) to 100 % (Isopoda:Oniscidea). Introduced species often occur in habitats different from their native ones. Isopod species richness was similar (4-5 species per forest) to the average values found in European temperate forests. Species evenness was lower in our study site with two species, Trachelipus rathkei and Cylisticus convexus being superabundant. The two species are different components of the European isopod fauna. Only T. rathkei is an expansive species often becoming dominant in a community. C. convexus is a synanthropic species, which in Central Europe is unable to invade natural forests. It is not known to reach the high abundances reported in North America. Change in soil community structure often results in altered rates and pathways of decomposition. In Baltimore species diversity of Silphidae affected the probability of small vertebrate carrion burial. We also found differences in the earthworm communities and microbial N-cycling between urban and rural forests. Urban forests had higher earthworm densities, and higher N-mineralization and nitrificaton rates than did rural forests. However, natural processes and anthropogenic impact may jointly be driving these differences.

Key words: soil, biodiversity, urbanization, invertebrate