Abandonment of croplands: problem or chance for grassland restoration? Case studies from Hungary

In Central-and Eastern Europe,the collapse of socialist regimes resulted in a transformation of state-owned agricultural cooperatives to privately owned lands from the early 1990s onwards.These socioeconomic processes resulted in landscape-scale changes in biodiversity,ecosystem services and agricultural production.In parallel,large-scale abandonment of croplands,especially on sandy,salty or fre-quently inundated areas,became common.Abandoned croplands are usually sensitive to species invasions,and are hotspots of noxious weeds,posing threats both to agriculture and nature conservation.Grassland restoration on former croplands can be an effective strategy for suppressing these species.Thus,a common goal of nature conservation and agriculture can be the restoration of grasslands on former croplands to(1)suppress weed and/or invasive species in line with the EU policy“Good Farming Practices”,(2)support animal husbandry by creating meadows or pastures,and to(3)recover biodiversity and ecosystem services.In the present paper we report“best practices”of grassland restoration projects from Hungary.Our aim was to compare the effectiveness of spontaneous grassland recovery vs.active grassland restoration by seed sowing in terms of the recovery of biodiversity and ecosystem services,such as weed control and biomass production.Our results showed that grassland restoration on abandoned fields offers a viable solution for restoring biodiversity and ecosystem services.Seed sowing ensures higher weed control and biomass pro-duction,but results in lower biodiversity compared to spontaneous recovery.Both restoration methods can be cost-effective,or even profitable even within a relatively short period of a nature conservation project.

Queens remate despite traumatic mating in stingless bees

Males can control female reproduction using genital plugs to impede access by rivals.In social bees,ants,and wasps,plugging may involve traumatic mating,with females being harmed.In stingless bees,chances are that plugs may promote ovarian activan,and are thought to ensure single mating—a general tendency among the social Hymenoptera.However,understanding on relationships between mating plugs,traumatic mating,and mating systems in stingless bees remains limited.To address this,we(1)compared mated queens of 7 Neotropical species to understand the patterns of copulatory marks in females and(2)compared pre-and post-mating genitalia of males and females in Melipona fasciculata to depict plug functional morphology.Data revealed an unprecedented consequence of mating in stingless bees:the characteristic marks left by mating plugs on female abdomens and the inferences that can be made from them.To our surprise,in 1 species M.fasciculata we found that queens retain the plug long after mating,and may carry it for the rest of their lives.All the other 6 species retained the plug for only a short period.Remated queens were only found in M.seminigra,whose multiple copulatory marks match previous findings of polyandry in this species.Our study shows that queens can remate,and suggests that male genital morphology may determine in part the time persistence of plugs.We conclude that traumatic mating plugs do not fully prevent remating in stingless bees and that mating systems are not uniform in this group.Nonetheless,exceptional cases of facultative polyandry in social insects—for example,when mating plugs fail—may confirm a general tendency for single mating in close link with efficient mating plugs.