Achieving sustainable biomaterials by maximising waste recovery

The waste hierarchy of ‘reduce, reuse, recycle, recover’ can be followed to improve the sustainability of a product, yet it is not applied in any meaningful way in the biomaterials industry which focuses more on sustainable sourcing of inputs. This paper presents the results of industry interviews and a focus group with experts to understand how waste recovery of biomaterials could become more widespread. Interview findings were used to develop three scenarios: (1) do nothing; (2) develop legislation; and (3) develop certification standards. These scenarios formed the basis for discussions at an expert focus group. Experts considered that action was required, rejecting the first scenario. No preference was apparent for scenarios (2) and (3). Experts agreed that there should be collaboration on collection logistics, promotion of demand through choice editing, product ‘purity’ could be championed though certification and there should be significant investment and research into recovery technologies. These considerations were incorporated into the development of a model for policy makers and industry to help increase biomaterial waste recovery.     

Comparing carbon fluxes between different stages of secondary succession of a karst grassland

Abandonment of marginal agricultural areas with subsequent secondary succession is a widespread type of land use change in Mediterranean and mountain areas of Europe, leading to important environmental consequences such as change in the water balance, carbon cycling, and regional climate. Paired eddy flux measurement design with grassland site and tree/shrub encroached site has been set-up in the Slovenian Karst (submediterranean climate region) to investigate the effects of secondary succession on ecosystem carbon cycling. The invasion of woody plant species was found to significantly change carbon balance shifting annual NEE from source to an evident sink. According to one year of data succession site stored ?126 ± 14 g C m^?2 y^?1 while grassland site emitted 353 ± 72 g C m^?2 y^?1. In addition, the seasonal course of CO₂ exchange differed between both succession stages, which can be related to differences in phenology, i.e. activity of prevailing plant species, and modified environmental conditions within forest fragments of the invaded site. Negligible effect of instrument heating was observed which proves the Burba correction in our ecosystems unnecessary. Unexpectedly high CO₂ emissions and large disagreement with soil respiration especially on the grassland site in late autumn indicate additional sources of carbon which cannot be biologically processes, such as degassing of soil pores and caves after rain events.     

Learning affects host discrimination behavior in a parasitoid wasp

Learning is generally predicted not to be important in host discrimination by parasitoids, because the stimuli involved are less variable than those used in habitat location. However, Anaphes victus (Hymenoptera: Mymaridae), an egg parasitoid of Listronotus oregonensis (Coleoptera: Curculionidae) apparently learns to associate external pheromones with the presence of a conspecific in a host. In this species, females can reject a parasitized host either after antennal drumming (antennal rejection) or after the insertion of their ovipositor (sting rejection). When they encountered a series of parasitized hosts, females A. victus learned to associate the presence of the external pheromone with the presence of the internal one. Learning lasted less than 4 h and occurred earlier in a series when the female marking the egg and the one detecting that mark were close relatives. This behavior could be adaptive because antennal rejection is faster than sting rejection. Received: 11 March 1997 / Accepted after revision: 30 August 1997