Steep declines in radioactive caesium after 30 years of monitoring alpine plants in mountain areas of central Norway

The Chernobyl accident exposed large areas of northern Europe to radiocaesium (137Cs). We investigated temporal and spatial variation in concentrations of radiocaesium among five functional groups of alpine plants at two mountain areas in central Norway over a 31-year period from 1991 to 2022. Average concentrations of radiocaesium were initially high in lichens and bryophytes at around 4600–6400 Bq/kg dry weight during 1991–1994 but then decreased dramatically over three decades to current concentrations of <200 Bq/kg for all plant groups in 2019–2022. The effective half-life of radiocaesium was estimated to be 4–6 years in lichens and mosses, 7–13 years in herbaceous plants, and 22–30 years in woody plants, which were less than the physical half-life of 30.2 years. Concentrations of radiocaesium were greater at the nutrient-poor site than at the nutrientrich site, probably due to greater deposition levels at higher elevations and the geographical pattern of the deposition. Functional groups of plants differed with higher concentrations among non-vascular than vascular plants. Common heather Calluna vulgaris was unusual among woody plants with high concentration of radiocaesium, especially in the new shoots. Our new estimates of concentrations and dynamics of radiocaesium for alpine plants in natural environments will be useful for modelling herbivore exposure and evaluating potential impacts on wildlife and human health. Chernobyl Plant uptake Lichens Mosses Radiocaesium Time series Vascular plantspublishedVersio

Chasing the bird: 3D acoustic tracking of aerial flight displays with a minimal planar microphone array

Tracking the flight patterns of birds and bats in three-dimensional space is central to key questions in evolutionary ecology but remains a difficult technical challenge. For example, complex aerial flight displays are common among birds breeding in open habitats, but information on flight performance is limited. Here, we demonstrate the feasibility of using a large ground-based 4-microphone planar array to track the aerial flight displays of the cryptic Jack Snipe Lymnocryptes minimus. The main element of male display flights resembles a galloping horse at a distance. Under conditions of sufficient signal-to-noise ratio and of vertical alignment with the microphone array, we successfully tracked male snipe in 3D space for up to 25 seconds with a total flight path of 280 m. The ’gallop’ phase of male snipe dropped from ca. 141 to 64 m above ground at an average velocity of 77 km/h and up to 92 km/h. Our project is one of the first applications of bioacoustics to measure 3D flight paths of birds under field conditions, and our results were consistent with our visual observations. Our microphone array and postprocessing workflow provides a standardised protocol that could be used to collect comparative data on birds with complex aerial flight displays. Acoustic display; animal flight; flight tracking; Jack Snipe; Lymnocryptes minimus; microphone arraypublishedVersio

Long-term decline in nest survival of a ground-nesting shorebird on a tropical island

Tropical islands harbour a disproportionally high number of endemic species, which face increasing threats due to habitat loss, disturbance and introduced alien predators. Long-term demographic studies are needed to understand how such threats may impact on population productivity. We report an investigation of a key demographic parameter, nest survival, over a 13-year period in a small ground-nesting shorebird on the island of Maio (Cabo Verde). Similar to many tropical islands, Maio is expected to face increased tourism, disturbance, and potential loss of nesting habitats. We monitored over 700 nests of the largest, year-round resident breeding population of Kentish plover in the Atlantic Ocean archipelago. Our work produced three important findings. First, we show that nest survival differed among the major habitats of the main breeding site, the Salinas do Porto Inglˆes, because nests in the salt-extraction area had higher daily survival rates DSR = 0.9654 ± 0.0076 SE than nests in grasslands DSR = 0.9557 ± 0.0038 SE. The salt-extraction is a dynamic habitat that is naturally regulated by rainfall and sea water inflow and managed with traditional methods for salt-extraction. Kentish plovers breed on small islets surrounded by salty water where mammalian predators may have restricted access. Second, we found that breeding densities of plovers decreased from 0.11 nests/ha to 0.03 nests/ ha over 13 years. Last, we show that nest survival declined from 0.9784 ± 0.0107 in 2007 to 0.8967 ± 0.0401 in 2019. We suggest that the declining breeding density and nest survival may be driven by a combination of ecological factors including predation by native and introduced species, and by increased human disturbance. To help maintain sustainable levels of nest survival and to ensure long-term persistence of this Kentish plover population, we propose to incorporate traditional Salinas management into direct conservation actions, to reduce human disturbance and manage nest predators to help nest survival on tropical islands. Breeding success Demography Disturbance Nest predation Nest survival MacaronesiapublishedVersio

Exposure of Nonbreeding Migratory Shorebirds to Cholinesterase Inhibiting Contaminants in the Western Hemisphere

Migratory shorebirds frequently forage and roost in agricultural habitats, where they may be exposed to cholinesterase-inhibiting pesticides. Exposure to organophosphorus and carbamate compounds, common anti-cholinesterases, can cause sublethal effects, even death. To evaluate exposure of migratory shorebirds to organophosphorus and carbamates, we sampled birds stopping over during migration in North America and wintering in South America. We compared plasma Cholinesterase activities and body masses of individuals captured at sites with no known sources of organophosphorus or carbamates to those captured in agricultural areas where agrochemicals were recommended for control of crop pests. In South America, plasma acetylcholinesterase and butyrylcholinesterase activity in Buff-breasted Sandpipers was lower at agricultural sites than at reference sites, indicating exposure to organophosphorus and carbamates. Results of plasma Cholinesterase reactivation assays and foot-wash analyses were inconclusive. A meta-analysis of six species revealed no widespread effect of agricultural chemicals on Cholinesterase activity. However, four of six species were negative for acetylcholinesterase and one of six for butyrylcholinesterase, indicating negative effects of pesticides on Cholinesterase activity in a subset of shorebirds. Exposure to Cholinesterase inhibitors can decrease body mass, but comparisons between treatments and hemispheres suggest that agrochemicals did not affect migratory shorebirds' body mass. Our study, one of the first to estimate of shorebirds' exposure to cholinesterase-inhibiting pesticides, suggests that shorebirds are being exposed to cholinesterase-inhibiting pesticides at specific sites in the winter range but not at migratory stopover sites. Future research should examine potential behavioral effects of exposure and identify other potential sites and levels of exposure.Instituto de Recursos BiológicosFil: Strum, Khara M. Kansas State University. Division of Biology; Estados UnidosFil: Hooper, Michael J. Texas Tech University. Institute of Environmental and Human Health; Estados UnidosFil: Johnson, Kevin A. Southern Illinois University. Department of Chemistry and Environmental Sciences; Estados UnidosFil: Lanctot, Richard B. United State Fish and Wildlife Service. Migratory Bird Management; Estados UnidosFil: Zaccagnini, Maria Elena. Instituto Nacional de Tecnología Agropecuaria (INTA). Instituto de Recursos Biológicos; ArgentinaFil: Sandercock, Brett K. Kansas State University. Division of Biology; Estados Unido

Risk assessment of the predatory mite Stratiolaelaps scimitus for biological control of varroa mites in beehives : Scientific opinion of the panel on plant health of the Norwegian scientific committee for food and environment

Source at https://vkm.no/.publishedVersio

Assessment of risk and risk-reducing measures related to the introduction and dispersal of the invasive alien carpet tunicate Didemnum vexillum in Norway

Didemnum vexillum is colonial sea squirt, a marine species which originates from the northwest Pacific; it was first recorded in Norway in November 2020. Didemnum vexillum is an alien species, meaning that it is a species that has been transferred from its original region to other regions of the world through human activity, and it had not previously been recorded in Norwegian waters. The species is regarded as having great invasive potential and having strong negative ecological effects on biodiversity. It is also considered to pose a risk to marine industries such as shipping and aquaculture, with possible major negative economic impacts.Assessment of risk and risk-reducing measures related to the introduction and dispersal of the invasive alien carpet tunicate Didemnum vexillum in NorwaypublishedVersio

Assessment of risk and risk-reducing measures related to the introduction and dispersal of the invasive alien carpet tunicate Didemnum vexillum in Norway

Didemnum vexillum is colonial sea squirt, a marine species which originates from the northwest Pacific; it was first recorded in Norway in November 2020. Didemnum vexillum is an alien species, meaning that it is a species that has been transferred from its original region to other regions of the world through human activity, and it had not previously been recorded in Norwegian waters. The species is regarded as having great invasive potential and having strong negative ecological effects on biodiversity. It is also considered to pose a risk to marine industries such as shipping and aquaculture, with possible major negative economic impacts.publishedVersio

Predator–prey interactions in the Arctic: DNA metabarcoding reveals that nestling diet of snow buntings reflects arthropod seasonality

Tundra arthropods are of considerable ecological importance as a seasonal food source for many arctic-breeding birds. Dietary composition and food preferences are rarely known, complicating assessments of ecological interactions in a changing environment. In our field study, we investigated the nestling diet of snow buntings (Plectrophenax nivalis (L., 1758)) breeding in Svalbard. We collected fecal samples from 8-day-old nestlings and assessed dietary composition by DNA metabarcoding. Simultaneously, the availability of potential prey arthropods was measured by pitfall trapping. Molecular analyses of nestling feces identified 31 arthropod taxa in the diet, whose proportions changed throughout the brood-rearing period. Changes in nestling diet matched varying abundances and emergence patterns of the tundra arthropod community. Snow buntings provisioned their offspring mainly with Diptera (true flies) based on both presence/absence and relative read abundance of diet items. At the beginning of the season in June, Chironomidae (nonbiting midges) and the scathophagid fly Scathophaga furcata (Say, 1823) dominated the diet, whereas the muscid fly Spilogona dorsata (Zetterstedt, 1845) dominated the diet later in July. When accounted for availability, muscid flies were selected positively among the most often provisioned food taxa. Our study demonstrates the ecological role of the snow bunting as a generalist arthropod predator and highlights DNA metabarcoding as a noninvasive technique for diet analyses with high taxonomical precision if sufficient DNA-sequence libraries are available