The impact of dense traffic on the breeding success in pied flycatchers (Ficedula hypoleuca) was studied using roadside nest-boxes. Nest site selection and breeding success of flycatchers were observed in relation to the distance from the road. The number of occupied territories was no higher closer to the road than it was deeper inside the forest. The distance to the road had no effect on the laying date, clutch size, or brood size. However, nests closer to the road were more likely to fail at the chick stage. The number of broods that were closer to roads and were lost completely was significantly higher than those further away. As a consequence, the number of fledglings per breeding attempt decreased closer to roads. The nestlings typically died as older chicks when the parent birds were providing them with maximum quantities of food. A possible reason for the declining reproductive success was the traffic-related mortality of parent birds, as weather conditions were not especially adverse for raising healthy offspring.

No abstract

/ Land bird densities in roadside habitats were studied in 17 locations in central Finland by the line transect method. Two transects were censused in each location. The first transect was situated 25 m from highway edge and the second transect 200 m away from the first one. The results suggested that land bird density was lower closer to highways. Species that avoided the road included willow warbler (Phylloscopus trochilus), crossbills (Loxia spp.), and tree pipit (Anthus trivialis). The composition of the bird community did not vary significantly between the compared transects. Some species appeared to favour road-forest edges but this could not be confirmed with our data. These species were not the same as have been reported to favor clear-fellings-mature forest edges. Therefore, the edge effect does not seem to be the most important factor controlling relative bird densities immediately adjacent and further away from highways. The likelihood of avoiding the problems the highways are causing for bird density are been discussed.KEY WORDS: Highways; Infrastructure; Bird density; Landscape ecology

Farming practices may reshape the structure of watersheds, water quality, and the health of aquatic organisms. Nutrient enrichment from agricultural pollution increases disease pressure in many host–pathogen systems, but the mechanisms underlying this pattern are not always resolved. For example, nutrient enrichment should strongly influence pools of aquatic environmental bacteria, which has the potential to alter microbiome composition of aquatic animals and their vulnerability to disease. However, shifts in the host microbiome have received little attention as a link between nutrient enrichment and diseases of aquatic organisms. We examined nutrient enrichment through the widespread practice of integrated pig–fish farming and its effects on microbiome composition of Brazilian amphibians and prevalence of the globally distributed amphibian skin pathogen Batrachochytrium dendrobatidis (Bd). This farming system drove surges in fecal coliform bacteria, disturbing amphibian skin bacterial communities such that hosts recruited higher proportions of Bd-facilitative bacteria and carried higher Bd prevalence. Our results highlight previously overlooked connections between global trends in land use change, microbiome dysbiosis, and wildlife disease. These interactions may be particularly important for disease management in the tropics, a region with both high biodiversity and continually intensifying anthropogenic pressures on aquatic wildlife habitats.