110 research outputs found

    Priority maps for pollinator habitat enhancement schemes in semi-natural grasslands

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    Conserving semi-natural grasslands, a threatened habitat type in European landscapes, is increasingly recognized as a measure to conserve pollinators. Our aim was to test if (a) prediction maps of solitary bee species richness could be used to rank semi-natural grasslands in terms of their potential for supporting wild bees, and (b) if such predictions extend current assessment criteria that determine which grasslands are eligible for being listed under habitat conservation schemes. We sampled wild bee communities in 52 semi-natural grasslands in southeast Norway. We conducted an across-year validation, using data from 2019 (32 sites) to model bee species richness, and used data from 2020 (20 sites) to validate predictions. We then conducted a leave-one-out cross-validation, iteratively using data from 51 sites to parameterize our model, and validating predictions on the withheld site. Finally, we used data from all 52 sites to update the model and tested if predicted species richness within the 1075 grasslands in our region was reflected in current assessment criteria scores assigned to those grasslands. Models from across-year, and leave-one-out cross-validations, predicted 39%, and 43% of bee species richness in semi-natural grasslands, respectively. Model predictions and current criteria of semi-natural grassland quality were not strongly related (R2 adjusted = 0.01), suggesting that prediction models can add a valuable extra dimension when prioritizing between semi-natural grassland for pollinator habitat conservation. Our findings illustrate how spatial prediction models can provide management authorities with a valuable tool for prioritizing where to direct habitat enhancement schemes in order to improve conservation effectiveness. Pollinators Bees Grassland Semi-natural Management ConservationpublishedVersio

    CO<sub>2</sub> minimum miscibility pressure determination of pure hydrocarbons in different temperatures using slimtube simulations

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    As wind energy deployment increases and larger wind-power plants are considered, bird fatalities through collision with moving turbine rotor blades are expected to increase. However, few (cost-) effective deterrent or mitigation measures have so far been developed to reduce the risk of collision. Provision of “passive” visual cues may enhance the visibility of the rotor blades enabling birds to take evasive action in due time. Laboratory experiments have indicated that painting one of three rotor blades black minimizes motion smear (Hodos 2003, Minimization of motion smear: Reducing avian collisions with wind turbines). We tested the hypothesis that painting would increase the visibility of the blades, and that this would reduce fatality rates in situ, at the Smøla wind-power plant in Norway, using a Before–After–Control–Impact approach employing fatality searches. The annual fatality rate was significantly reduced at the turbines with a painted blade by over 70%, relative to the neighboring control (i.e., unpainted) turbines. The treatment had the largest effect on reduction of raptor fatalities; no white-tailed eagle carcasses were recorded after painting. Applying contrast painting to the rotor blades significantly reduced the collision risk for a range of birds. Painting the rotor blades at operational turbines was, however, resource demanding given that they had to be painted while in-place. However, if implemented before construction, this cost will be minimized. It is recommended to repeat this experiment at other sites to ensure that the outcomes are generic at various setting

    Yield-biodiversity trade-off in patchy fields of Miscanthus × giganteus

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    Increasing crop productivity to meet rising demands for food and energy, but doing so in an environmentally sustainable manner, is one of the greatest challenges for agriculture to date. In Ireland, Miscanthus 9 giganteus has the potential to become a major feedstock for bioenergy production, but the economic feasibility of its cultivation depends on high yields. Miscanthus fields can have a large number of gaps in crop cover, adversely impacting yield and hence economic viability. Predominantly positive effects of Miscanthus on biodiversity reported from previous research might be attributable to high crop patchiness, particularly during the establishment phase. The aim of this research was to assess crop patchiness on a field scale and to analyse the relationship between Miscanthus yield and species richness and abundance of selected taxa of farmland wildlife. For 14 Miscanthus fields at the end of their establishment phase (4–5 years after planting), which had been planted either on improved grassland (MG) or tilled arable land (MT), we determined patchiness of the crop cover, percentage light penetration (LP) to the lower canopy, Miscanthus shoot density and height, vascular plants and epigeic arthropods. Plant species richness and noncrop vegetation cover in Miscanthus fields increased with increasing patchiness, due to higher levels of LP to the lower canopy. The species richness of ground beetles and the activity density of spiders followed the increase in vegetation cover. Plant species richness and activity density of spiders on both MT and MG fields, as well as vegetation cover and activity density of ground beetles on MG fields, were negatively associated with Miscanthus yield. In conclusion, positive effects of Miscanthus on biodiversity can diminish with increasing productivity. This matter needs to be considered when assessing the relative ecological impacts of developing biomass crops in comparison with other land use. Keywords: Araneae, Carabidae, crop cover, light penetration, Miscanthus establishment, patchiness, vascular plants, vegetation coverYield-biodiversity trade-off in patchy fields of Miscanthus × giganteuspublishedVersio

    Designing a surveillance program for early detection of alien plants and insects in Norway

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    Naturalized species of alien plants and animals comprise < 3% of biodiversity recorded in Norway but have had major impacts on natural ecosystems through displacement of native species. Encroachment of alien species has been especially problematic for coastal sites close to transport facilities and urban areas with high density housing. The goal of our field project was to design and test a surveillance program for early detection of alien species of vascular plants and terrestrial insects at the first phase of establishment in natural areas. In our 3-year project (2018–2020), we sampled 60 study plots in three counties in the Oslofjord region of southern Norway. Study plots (6.25 ha) were selected by two criteria: manual selection based on expert opinion (27 plots) or by random selection based on weights from a hotspot analysis of occurrence of alien species (33 plots). Vascular plants were surveyed by two experienced botanists who found a total of 239 alien species of vascular plants in 95 rounds of surveys. Insects and other invertebrates were captured with a single Malaise trap per site, with 3–4 rounds of repeated sampling. We used DNA-metabarcoding to identify invertebrates based on DNA extractions from crushed insects or from the preservative media. Over 3500 invertebrate taxa were detected in 255 rounds of sampling. We recorded 20 alien species of known risk, and 115 species that were new to Norway, including several ‘doorknocker’ species identified by previous risk assessments. We modeled the probabilities of occupancy (ψ) and detection (p) with occupancy models with repeated visits by multiple observers (vascular plants) or multiple rounds of sampling (insects). The two probabilities covaried with risk category for alien organisms and both were low for species categorized as no known or low risk (range = 0.052–0.326) but were higher for species categorized as severe risk (range = 0.318–0.651)... Arthropods · DNA-metabarcoding · Early detection · Invasive · Invertebrates · Occupancy models · Rapid response · Study design · Vascular plantsDesigning a surveillance program for early detection of alien plants and insects in NorwaypublishedVersio

    A novel coupling control with decision-maker and PID controller for minimizing heating energy consumption and ensuring indoor environmental quality

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    Due to climate change, global energy crisis, and high-quality life requirement for people, decreasing building energy consumption and enhancing indoor environment quality through control of heating, ventilation, and air conditioning systems tend to be increasingly important. Therefore, favorable control methods for heating and ventilation systems are urgently necessary. In this work, a new coupling control with decision-maker was proposed, developed, and investigated; meanwhile, several demand controlled ventilation strategies combined with heating control method was compared considering heating energy consumption, thermal comfort, and indoor air quality. In order to properly model the service systems, the air change rates and thermal time constants have been first measured in a reference office installed with commonly applied bottom-hinged tilted windows in our low-energy building supplied by geothermal district heating. Then, simulations have been carried out across two typical winter days in the reference office. The results illustrate that the proposed combination of suitable heating and demand controlled ventilation coupling control methods with decision-maker and proportional-integral-derivative (PID) controller could greatly reduce heating consumption in the reference room during the office time: around 52.4% (4.4 kW h energy saving) per day in winter in comparison to a commonly suggested method of intensive and brief airing. At the same time, it could ensure indoor CO2 concentration to keep within the pre-set ranges (Pettenkofer limit: 1000 ppm) as well as low variations of indoor temperature (standard deviation (SD): 0.1°C)

    Emerging technologies revolutionise insect ecology and monitoring

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    Insects are the most diverse group of animals on Earth, but their small size and high diversity have always made them challenging to study. Recent technologi- cal advances have the potential to revolutionise insect ecology and monitoring. We describe the state of the art of four technologies (computer vision, acoustic monitoring, radar, and molecular methods), and assess their advantages, current limitations, and future potential. We discuss how these technologies can adhere to modern standards of data curation and transparency, their implications for citizen science, and their potential for integration among different monitoring programmes and technologies. We argue that they provide unprecedented possibilities for insect ecology and monitoring, but it will be important to foster international standards via collaborationpublishedVersio

    Six pelagic seabird species of the North Atlantic engage in a fly-and-forage strategy during their migratory movements

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    Bird migration is commonly defined as a seasonal movement between breeding and non-breeding grounds. It generally involves relatively straight and directed large-scale movements, with a latitudinal change, and specific daily activity patterns comprising less or no foraging and more traveling time. Our main objective was to describe how this general definition applies to seabirds. We investigated migration characteristics of 6 pelagic seabird species (little auk Alle alle, Atlantic puffin Fratercula arctica, common guillemot Uria aalge, Brünnich’s guillemot U. lomvia, black-legged kittiwake Rissa tridactyla and northern fulmars Fulmarus glacialis). We analysed an extensive geolocator positional and saltwater immersion dataset from 29 colonies in the North-East Atlantic and across several years (2008-2019). We used a novel method to identify active migration periods based on segmentation of time series of track characteristics (latitude, longitude, net-squared displacement). Additionally, we used the saltwater immersion data of geolocators to infer bird activity. We found that the 6 species had, on average, 3 to 4 migration periods and 2 to 3 distinct stationary areas during the non-breeding season. On average, seabirds spent the winter at lower latitudes than their breeding colonies and followed specific migration routes rather than non-directionally dispersing from their colonies. Differences in daily activity patterns were small between migratory and stationary periods, suggesting that all species continued to forage and rest while migrating, engaging in a ‘fly-and-forage’ migratory strategy. We thereby demonstrate the importance of habitats visited during seabird migrations as those that are not just flown over, but which may be important for re-fuelling.publishedVersio

    Twilight foraging enables European shags to survive the winter across their latitudinal range

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    Species breeding at high latitudes face a significant challenge of surviving the winter. Such conditions are particularly severe for diurnal marine endotherms such as seabirds. A critical question is therefore what behavioural strategies such species adopt to maximise survival probability. We tested 3 hypotheses: (1) they migrate to lower latitudes to exploit longer day length (‘sun-chasing’), (2) they forage at night (‘night-feeding’), or (3) they target high-quality food patches to minimise foraging time (‘feasting’). We studied the winter migration and foraging strategies of European shags Phalacrocorax aristotelis from 6 colonies across a latitudinal gradient from temperate regions to north of the Arctic Circle using geolocators deployed over 11 winters. We found evidence for ‘sun-chasing’, whereby average southerly movements were greatest from colonies at higher latitudes. However, a proportion of individuals from higher latitudes remained resident in winter and, in the absence of daylight, they foraged during twilight and only very occasionally during the night. At lower latitudes, there was little evidence that individuals migrated south, nocturnal feeding was absent, and twilight feeding was infrequent, suggesting that there was sufficient daylight in winter. There was no evidence that winter foraging time was lowest at higher latitudes, as predicted by the ‘feasting’ hypothesis. Our results suggest that shags adopt different behavioural strategies to survive the winter across their latitudinal range, dictated by the differing light constraints. Our study highlights the value of multi-colony studies in testing key hypotheses to explain population persistence in seabird species that occur over large latitudinal ranges
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