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- Allanach, Benjamin C., et al.
(författare)
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Simple and statistically sound strategies for analysing physical theories
- 2022
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Ingår i: Reports on progress in physics (Print). - : Institute of Physics Publishing (IOPP). - 0034-4885 .- 1361-6633. ; 85:5
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Forskningsöversikt (refereegranskat)abstract
- Physical theories that depend on many parameters or are tested against data from many different experiments pose unique challenges to statistical inference. Many models in particle physics, astrophysics and cosmology fall into one or both of these categories. These issues are often sidestepped with statistically unsound ad hoc methods, involving intersection of parameter intervals estimated by multiple experiments, and random or grid sampling of model parameters. Whilst these methods are easy to apply, they exhibit pathologies even in low-dimensional parameter spaces, and quickly become problematic to use and interpret in higher dimensions. In this article we give clear guidance for going beyond these procedures, suggesting where possible simple methods for performing statistically sound inference, and recommendations of readily-available software tools and standards that can assist in doing so. Our aim is to provide any physicists lacking comprehensive statistical training with recommendations for reaching correct scientific conclusions, with only a modest increase in analysis burden. Our examples can be reproduced with the code publicly available at Zenodo.
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- Fox, Anthony D., et al.
(författare)
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Seeking explanations for recent changes in abundance of wintering Eurasian Wigeon (Anas penelope) in northwest Europe
- 2016
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Ingår i: Ornis Fennica. - 0030-5685. ; 93:1, s. 12-25
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Tidskriftsartikel (refereegranskat)abstract
- We analysed annual changes in abundance of Eurasian Wigeon (Anas penelope) derived from mid-winter International Waterbird Census data throughout its northwest European flyway since 1988 using log-linear Poisson regression modelling. Increases in abundance in the north and east of the wintering range (Norway, Sweden, Denmark, Germany, Switzerland), stable numbers in the central range (Belgium, Netherlands, UK and France) and declining abundance in the west and south of the wintering range (Spain and Ireland) suggest a shift in wintering distribution consistent with milder winters throughout the range. However, because over 75% of the population of over 1 million individuals winters in Belgium, the Netherlands, UK and France, there was no evidence for a major movement in the centre of gravity of the wintering distribution. Between-winter changes in overall flyway abundance were highly significantly positively correlated (P = 0.003) with reproductive success measured by age ratios in Danish hunter wing surveys and less strongly and inversely correlated (P = 0.05) with mean January temperatures in the centre of the wintering range, suggesting that winter severity may also contribute to influence survival. However, adding winter severity to a model predicting population size based on annual reproductive success alone did not contribute to more effectively modelling the observed changes in population size. Patterns in annual reproductive success seem therefore to largely explain the recent dynamics in population size of northwest European Wigeon. Summer NAO significantly and positively explained 27% of variance in annual breeding success. Other local factors such as eutrophication of breeding sites and changes in predation pressure undoubtedly contribute to changes in the annual production of young and differences in hunting pressure as well as winter severity affect annual survival rates. However, it seems likely that the observed flyway population trend since 1988 has been mostly influenced by climate effects on the breeding grounds affecting reproductive success and marginally on the winter quarters affecting survival. We urge improved demographic monitoring of the population to better assess annual survival and reproductive success. We also recommend development of an adaptive management framework to remove uncertainties in our knowledge of Wigeon population dynamics as information is forthcoming to better inform management, especially to attempt to harmonise the harvest with annual changes in demography to ensure sustainable exploitation of this important quarry species now and in the future.
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- Gaget, Elie, et al.
(författare)
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Benefits of protected areas for nonbreeding waterbirds adjusting their distributions under climate warming
- 2021
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Ingår i: Conservation Biology. - : Wiley. - 0888-8892 .- 1523-1739. ; 35:3, s. 834-845
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Tidskriftsartikel (refereegranskat)abstract
- Climate warming is driving changes in species distributions and community composition. Many species have a so-called climatic debt, that is, shifts in range lag behind shifts in temperature isoclines. Inside protected areas (PAs), community changes in response to climate warming can be facilitated by greater colonization rates by warm-dwelling species, but also mitigated by lowering extirpation rates of cold-dwelling species. An evaluation of the relative importance of colonization-extirpation processes is important to inform conservation strategies that aim for both climate debt reduction and species conservation. We assessed the colonization-extirpation dynamics involved in community changes in response to climate inside and outside PAs. To do so, we used 25 years of occurrence data of nonbreeding waterbirds in the western Palearctic (97 species, 7071 sites, 39 countries, 1993–2017). We used a community temperature index (CTI) framework based on species thermal affinities to investigate species turnover induced by temperature increase. We determined whether thermal community adjustment was associated with colonization by warm-dwelling species or extirpation of cold-dwelling species by modeling change in standard deviation of the CTI (CTISD). Using linear mixed-effects models, we investigated whether communities in PAs had lower climatic debt and different patterns of community change than communities outside PAs. For CTI and CTISD combined, communities inside PAs had more species, higher colonization, lower extirpation, and lower climatic debt (16%) than communities outside PAs. Thus, our results suggest that PAs facilitate 2 independent processes that shape community dynamics and maintain biodiversity. The community adjustment was, however, not sufficiently fast to keep pace with the large temperature increases in the central and northeastern western Palearctic. Our results underline the potential of combining CTI and CTISD metrics to improve understanding of the colonization-extirpation patterns driven by climate warming.
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- Gaget, Elie, et al.
(författare)
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Protected area characteristics that help waterbirds respond to climate warming
- 2022
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Ingår i: Conservation Biology. - : Wiley. - 0888-8892 .- 1523-1739. ; 36:4
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Tidskriftsartikel (refereegranskat)abstract
- Protected area networks help species respond to climate warming. However, the contribution of a site's environmental and conservation-relevant characteristics to these responses is not well understood. We investigated how composition of nonbreeding waterbird communities (97 species) in the European Union Natura 2000 (N2K) network (3018 sites) changed in response to increases in temperature over 25 years in 26 European countries. We measured community reshuffling based on abundance time series collected under the International Waterbird Census relative to N2K sites’ conservation targets, funding, designation period, and management plan status. Waterbird community composition in sites explicitly designated to protect them and with management plans changed more quickly in response to climate warming than in other N2K sites. Temporal community changes were not affected by the designation period despite greater exposure to temperature increase inside late-designated N2K sites. Sites funded under the LIFE program had lower climate-driven community changes than sites that did not received LIFE funding. Our findings imply that efficient conservation policy that helps waterbird communities respond to climate warming is associated with sites specifically managed for waterbirds.
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- Lehikoinen, Aleksi, et al.
(författare)
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Declining population trends of European mountain birds
- 2019
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Ingår i: Global Change Biology. - : Wiley. - 1354-1013 .- 1365-2486. ; 25:2, s. 577-588
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Tidskriftsartikel (refereegranskat)abstract
- Mountain areas often hold special species communities, and they are high on the list of conservation concern. Global warming and changes in human land use, such as grazing pressure and afforestation, have been suggested to be major threats for biodiversity in the mountain areas, affecting species abundance and causing distribution shifts towards mountaintops. Population shifts towards poles and mountaintops have been documented in several areas, indicating that climate change is one of the key drivers of species’ distribution changes. Despite the high conservation concern, relatively little is known about the population trends of species in mountain areas due to low accessibility and difficult working conditions. Thanks to the recent improvement of bird monitoring schemes around Europe, we can here report a first account of population trends of 44 bird species from four major European mountain regions: Fennoscandia, UK upland, south-western (Iberia) and south-central mountains (Alps), covering 12 countries. Overall, the mountain bird species declined significantly (−7%) during 2002–2014, which is similar to the declining rate in common birds in Europe during the same period. Mountain specialists showed a significant −10% decline in population numbers. The slope for mountain generalists was also negative, but not significantly so. The slopes of specialists and generalists did not differ from each other. Fennoscandian and Iberian populations were on average declining, while in United Kingdom and Alps, trends were nonsignificant. Temperature change or migratory behaviour was not significantly associated with regional population trends of species. Alpine habitats are highly vulnerable to climate change, and this is certainly one of the main drivers of mountain bird population trends. However, observed declines can also be partly linked with local land use practices. More efforts should be undertaken to identify the causes of decline and to increase conservation efforts for these populations.
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- Pavón-Jordán, Diego, et al.
(författare)
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Habitat- and species-mediated short- and long-term distributional changes in waterbird abundance linked to variation in European winter weather
- 2019
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Ingår i: Diversity and Distributions. - : Wiley. - 1366-9516. ; 25:2, s. 225-239
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Tidskriftsartikel (refereegranskat)abstract
- Aim: Many species are showing distribution shifts in response to environmental change. We explored (a) the effects of inter-annual variation in winter weather conditions on non-breeding distributional abundance of waterbirds exploiting different habitats (deep-water, shallow water, farmland) and (b) the long-term shift in the population centroid of these species and investigate its link to changes in weather conditions. Location: Europe. Methods: We fitted generalized additive mixed Models to a large-scale, 24-year dataset (1990–2013) describing the winter distributional abundance of 25 waterbird species. We calculated the annual and long-term (3-year periods) population centroid of each species and used the winter North Atlantic Oscillation (NAO) index to explain the inter-annual and long-term shifts in their location. Results: (a) Year-to-year southwestwards shifts in the population centroids of deep- and shallow-water species were linked to negative NAO values. Shallow-water species shifted northeastwards associated with positive NAO values and the distance shifted increased with increasing NAO. Deep-water species shifted northeastwards up to zero NAO indices, but showed no further increase at higher NAO values. (b) Deep-water species showed long-term northeastwards shifts in distributional abundance throughout the 1990s and the 2000s. Shallow-water species, on the other hand, shifted northeastwards during the 1990s and early 2000s, but southwestwards thereafter. There were no significant links between the NAO and year-to-year movements or long-term shifts in farmland species’ population centroid. Main Conclusions: We provide evidence for a link between both year-to-year and long-term changes in waterbird winter distributional abundances at large geographical scales to short- and long-term changes in winter weather conditions. We also show that species using shallow water, deep-water and farmland habitats responded differently, especially at high NAO values. As well as important ecological implications, these findings contribute to the development of future conservation measures for these species under current and future climate change.
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