Terrestrial isopods are decomposers in forest ecosystems and aid in biogeochemical cycling.  Despite their important role in ecosystem function, little is known about the microhabitat distribution of various species or how collection methods may under- or over-represent certain species.  We tested four methods of collecting terrestrial isopods:  baits (carrots and potatoes), drop cans, coverboards and leaf litter searching.  We collected isopods in two deciduous forest stands on the RIT campus (Henrietta, NY), and simultaneously collected habitat information about the collection location (e.g. leaf litter depth, woody debris density, herbaceous cover, etc.)

Results/Conclusions

In four trials over two weeks, we obtained 512 individuals, of which 394 were identified to species (the others were juveniles too young to identify).  In all, five species were found.  The number of isopods was non-randomly distributed among the collection methods (χ² = 185.3; p < 0.001), with 46% found on the baits, and only 9% found in the drop cans.  Additionally, while most species were found most commonly on the baits, Philoscia muscorum was found most often under the coverboard (χ² = 41.1; p < 0.001). Our results suggest that the method of collecting terrestrial isopods should be matched to the research question, because the collection method can influence the proportion of different species collected. Furthermore, combining or comparing results from studies that have used different collection methods may not be valid.