Materials based on polystyrene and starch copolymers are used in food packaging, water pollution treatment, and textile industry, and their biodegradability is a desired characteristic. In order to examine the degradation patterns of modified, biodegradable derivates of polystyrene, which may keep its excellent technical features but be more environmentally friendly at the same time, polystyrene-graft-starch biomaterials obtained by emulsion polymerization in the presence of new type of initiator/activator pair (potassium persulfate/different amines) were subjected to 6-month biodegradation by burial method in three different types of commercially available soils: soil rich in humus and soil for cactus and orchid growing. Biodegradation was monitored by mass decrease, and the highest degradation rate was achieved in soil for cactus growing (81.30 %). Statistical analysis proved that microorganisms in different soil samples have different ability of biodegradation, and there is a significant negative correlation between the share of polystyrene in copolymer and degree of biodegradation. Grafting of polystyrene on starch on one hand prevents complete degradation of starch that is present (with maximal percentage of degraded starch ranging from 55 to 93 %), while on the other hand there is an upper limit of share of polystyrene in the copolymer (ranging from 37 to 77 %) that is preventing biodegradation of degradable part of copolymers.

Overabundant white-tailed deer are one of the most serious threats to woodland plant communities in the Chicago area. Moreover, the abundant deer in a highly populated area causes economic harm and poses hazards to human safety through collisions with vehicles. The artificial conditions causing the overabundance and resulting consequences qualify the white-tailed deer in the Chicago area to be considered as “native invaders”. We examined the benefits of culling deer at a Chicago-area woodland preserve by comparing browse rates on four endangered plant species from years before culling began with years with culling. We also examined deer–vehicle collision and traffic flow rates on area roads from years before culling began and years with culling to assess whether population reductions may have benefited road safety in the area. All four endangered plant species (three orchid species and sweet fern) had lower browse rates in years with culls, although the decreased browsing rates were statistically distinguishable for only two of the species (grass pink orchid and sweet fern). After first verifying that traffic flow rates did not decrease from pre-cull years to years with culls, we analyzed the Illinois Department of Transportation data from area roads based on deer–vehicle collisions causing >US$500 in damage and showed a one-third reduction in deer–vehicle collisions. An economic analysis showed a cost savings during the cull years of US$0.6 million for reducing browsing to just these four monitored plant species and the reduction in deer–vehicle collisions.