Effects of differing restoration methods on bottomland hardwood litter arthropods

We sampled litter-dwelling arthropods (using pitfall traps) in plots that had been subjected to different restoration methods in bottomland hardwood habitat in Sharkey County, MS.  Experimental treatments included 1) Native “natural” regeneration (NR); 2) Oak seed (Quercus nuttallii) directly seeded (SEED); 3) Oak seedlings planted (PLN); and 4)  Oak seedlings interplanted between rows of a cottonwood (Populus deltoides) plantation (CW), in a randomized complete block design.  The blocking factor reflected differences in elevation which are related to susceptibility of the blocks to flooding.  Preliminary findings suggested the collembolan family Sminthuridae was affected by block, but these effects depended upon date of sampling.  In winter, this group was significantly more abundant in blocks with higher elevation, whereas in summer the lower-lying block had greatest abundance.  Other groups exhibiting significant responses to the blocking factor (during Summer) included Formicidae, Entomobryidae, Acari, and Carabidae.  In general, these groups were more abundant in the lower-lying block, possibly indicating moisture dependence in these organisms.  The sminthurid collembolans also had variable responses to the restoration treatments.  They were more abundant in CW plots than in NR plots during the summer sampling, but the opposite pattern was observed in winter.  Other organisms showing restoration treatment effects included three (Sphecidae, Hemiptera, and Hypogastruridae) significantly more abundant in the CW, and one (Orthoptera) more abundant in the NR treatment.  These results suggest that CW treatments may serve to foster litter-dwelling organisms (and possibly jump-start their associated functions) in hardwood restorations on the Mississippi Delta.