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NIBIOs ansatte publiserer flere hundre vitenskapelige artikler og forskningsrapporter hvert år. Her finner du referanser og lenker til publikasjoner og andre forsknings- og formidlingsaktiviteter. Samlingen oppdateres løpende med både nytt og historisk materiale. For mer informasjon om NIBIOs publikasjoner, besøk NIBIOs bibliotek.

2020

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Understanding interactions between individual animals and their resources is fundamental to ecology. Agent-Based Models (ABMs) offer an opportunity to study how individuals move given the spatial distribution and characteristics of their resources. When contrasted with empirical individual-resource network data, ABMs can be a powerful method to detect the processes behind observed movement patterns, as they allow for a complete and quantitative analysis of the agent-to-environment relationships. Here we use the small-scale, within-patch movement of bumblebees (Bombus pascuorum) as a case study to demonstrate how ABMs can be combined with network statistics to provide a deeper understanding of the mechanisms behind the interactions between individuals and their resources. We build an ABM that explicitly simulates the influence of distance to the nearest flowering plant (allowing minimal energy expenditure and maximum time spent foraging), plant height and number of flower heads (as a proxy of food availability) on local foraging decisions of bumblebees. The relative importance of these three elements is determined using pattern-oriented modelling (POM), where we confront the network statistics (number of visited plants, number of interactions, nestedness and modularity) of a real B. pascuorum individual-resource network with the emergent patterns of our ABM. We also explore the model results using spatial analysis. The model is able to reproduce the observed network statistics. Despite the complex behaviour of bumblebees, our results show a surprisingly precise match between the structure of the simulated and empirical networks after adjusting a single model parameter controlling the importance of distance to the next plant visited. Our study illustrates the potential of combining field data, ABMs and individual-resource networks for evaluating small-scale, within-patch movement decisions to better understand animal movements in natural habitats. We discuss the benefits of our approach when compared to more classical statistical methods, and its ability to test various scenarios in a new or altered environment.

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Key words: Ursus maritimus, CITES, polar bear, Non-Detriment Finding, Norwegian Scientific Committee for Food and Environment, Norwegian Environment Agency, VKM Background: Canada is the only nation in the world that allows commercial export of polar bear products harvested from its own wild populations. Norway is among the destinations for exported material. Polar bears are listed on CITES appendix II and on list B of the Norwegian CITES Regulation. Import of harvested polar bears to Norway requires both export permits from the Canadian CITES authorities and import permits from the Norwegian Environment Agency. Consequently, a Non-Detriment Finding (NDF) is mandated and was commissioned by the Norwegian Environment Agency (Norwegian Management Authority for CITES) to the Norwegian Scientific Committee for Food and Environment (VKM) (Norway’s CITES Scientific Authority). The NDF is a scientific risk assessment evaluating whether or not international trade can be detrimental to the survival of polar bears. The risk assessment may also be used by the Norwegian Environment Agency to assess whether the polar bears should be placed on Norwegian CITES list A. Currently, the IUCN/SSC Polar Bear Specialist Group (PBSG) recognizes 19 subpopulations of polar bears in the circumpolar Arctic, of which 13 reside wholly (9) or partly (4) in Canada. Together, these 13 populations account for about two thirds of the world’s total polar bear population. This risk assessment considers the populations that are within the hunting areas. Methods: VKM has reviewed current knowledge about polar bear biological characteristics, population status and trends in subpopulations. Scenarios for the future development of the Arctic environment, to which the species is inextricably adapted, are presented. Habitat loss due to declining sea ice is widely recognized as the main threat to polar bears, and this, as well as other obstacles to the species survival, has been evaluated. The various legislations, regulations and monitoring regimes of the range countries are briefly summarised. Moreover, international trade in polar bear products has been analysed. VKM has further undertaken an assessment of data quality and uncertainties. In order to gain access to the most recent information on polar bear biology and management, four scientists from the PBSG were interviewed and the transcripts of the interviews (with consent from the hearing experts) are attached to this report. Results: The best scientific knowledge available for polar bears in Canada suggests that four subpopulations are in decline, two are stable, and one is increasing, while the population trends for the remaining subpopulations are unknown. Noteworthy, all the estimates of population size are highly uncertain. Survey methods also changed between the 2008 and 2018 population estimates used for quota setting. Moreover, data are in most areas collected too infrequently to detect rapid changes in population size. Particularly, under changing environmental conditions. The prognosis for the Arctic marine environment points towards continuing habitat loss and inevitably further decline for the polar bear population. Analyses of data from the CITES trade database reveal a dynamic international market for polar bear products with significant changes in destination countries and the purpose for transactions. The United States was the main importer of polar bear products, mainly hunting trophies, until listing the polar bear as a threatened species in 2008. In more recent years, China has become the major importer, with hides being the preferred product. Simultaneously with these changes, there has been a significant increase in the price of polar bear hides. Conclusion: Several polar bear subpopulations are in decline. Predictions of continuing habitat loss points to further decline. While not the main threat to polar bear survival, international trade .......

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1. Ecological network theory hypothesizes that the structuring of species interactions can convey stability to the system. Investigating how these structures react to species loss is fundamental for understanding network disassembly or their robustness. However, this topic has mainly been studied in‐silico so far. 2. Here, in an experimental manipulation, we sequentially removed four generalist plants from real plant–pollinator networks. We explored the effects on, and drivers of, species and interaction disappearance, network structure and interaction rewiring. First, we compared both the local extinctions of species and interactions and the observed network indices with those expected from three co‐extinction models. Second, we investigated the trends in network indices and rewiring rate after plant removal and the pollinator tendency at establishing novel links in relation to their proportional visitation to the removed plants. Furthermore, we explored the underlying drivers of network assembly with probability matrices based on ecological traits. 3. Our results indicate that the cumulative local extinctions of species and interactions increased faster with generalist plant loss than what was expected by co‐extinction models, which predicted the survival or disappearance of many species incorrectly, and the observed network indices were lowly correlated to those predicted by co‐extinction models. Furthermore, the real networks reacted in complex ways to plant removal. First, network nestedness decreased and modularity increased. Second, although species abundance was a main assembly rule, opportunistic random interactions and structural unpredictability emerged as plants were removed. Both these reactions could indicate network instability and fragility. Other results showed network reorganization, as rewiring rate was high and asymmetries between network levels emerged as plants increased their centrality. Moreover, the generalist pollinators that had frequently visited both the plants targeted of removal and the non‐target plants tended to establish novel links more than who either had only visited the removal plants or avoided to do so. 4. With the experimental manipulation of real networks, our study shows that despite their reorganizational ability, plant–pollinator networks changed towards a more fragile state when generalist plants are lost.

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Key words: VKM, risk assessment, Norwegian Scientific Committee for Food and Environment, Norwegian Environment Agency, Norwegian Food Safety Authority Introduction: The Norwegian Environment Agency and the Norwegian Food Safety Authority asked the Norwegian Scientific Committee for Food and Environment to assess the risk to Norwegian biodiversity, to the productivity of native salmonid populations, and to aquaculture, from the spread and establishment of pink salmon in Norwegian rivers, and to assess mitigation measures to prevent the spread and establishment of this alien species. Pink salmon is native to rivers around the northern Pacific Ocean. The species usually has a strict two-year life cycle, with populations spawning in even and odd years being genetically isolated. Fertilized eggs of pink salmon were transferred from Sakhalin Island to Northwest Russia in the late 1950s, and fry were released in rivers draining to the White Sea. The first abundant return to rivers in Northwest Russia, as well as to Norway and other countries in northwestern Europe, was recorded in 1960. Stocking with fish from Sakhalin was terminated in 1979. By then, no self-sustaining populations had been established. From 1985 onwards, stocking in White Sea rivers was resumed with fish from rivers in the more northerly Magadan oblast on the Russian Pacific, resulting in the establishment of reproducing populations. Stocking was continued until 1999, when the last batch of evenyear fertilized eggs was imported, and the fry released in spring 2000. Thus, all pink salmon caught after 2001 in the Northeast Atlantic and the Atlantic side of the Arctic Ocean including the Barents Sea, as well as in rivers draining into these seas, are the result of reproduction in the wild. Pink salmon is now established with abundant and increasing stocks in Northwest Russia and regular occurrence in rivers in eastern Finnmark. Catches of odd-year adult pink salmon in Northwest Russia were usually below 100 tonnes before 2001 and increased to an annual average of 220.5 tonnes during the period 2001-2017. Even-year returns are smaller than odd-year returns both in Northwest Russia and in Norway. The number of pink salmon recorded in Norwegian rivers peaked in 2017, with a high number of fish in eastern Finnmark, and substantial numbers recorded in rivers all along the coast of Norway and in other European countries. In 2019, the area with abundant returns expanded in comparison with 2017, to include rivers in western Finnmark and Troms. The recorded numbers were perhaps lower in southern Norway in 2017 than in 2019 (full statistics not available when this report was finalised), but also in southern Norway there were more pink salmon in 2019 than in any year before 2017. The large numbers of pink salmon in western Finnmark and Troms in 2019 may indicate an expansion of the area in Norway with abundant odd-year pink salmon returns. In some small rivers in eastern Finnmark, between 1000 and 1500 pink salmon were fished out by local people in 2019, demonstrating the magnitude of the potential impact in terms of numbers of pink salmon. We cannot rule out that this will not happen over larger parts of Norway in the coming years. The even-year strain of pink salmon only occurs in low numbers in Russian rivers, as well as Norwegian, rivers. Adult pink salmon enter the rivers from early July, and spawning occurs in AugustSeptember. Spawning habitat requirements are like those of native salmonids: Atlantic salmon, brown trout, and Arctic charr. Spawning of pink salmon occurs earlier than the native salmonids, but observations in 2019 indicate a possible overlap with native salmonids in September in northern Norway. . Pink salmon eggs hatch in late winter or spring, and the alevins remain in the gravel until most of the yolk sac has been resorbed. Emerging fry are approximately 30 mm in length. ...................

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Global economic value of agriculture production resulting from animal pollination services has been estimated to be $235–$577 billion. This estimate is based on quantification of crops that are available at the global markets, and mainly originates from countries with precise information about quantities of agriculture production, exports, and imports. In contrast, knowledge about the contribution of pollinators to household food and income in small-scale farming at local and regional scales is still lacking, especially for developing countries where the availability of agricultural statistics is limited. Although the global decline in pollinator diversity and abundance has received much attention, relatively little effort has been directed towards understanding the role of pollinators in small-scale farming systems, which feed a substantial part of the world’s population. Here, we have assessed how local farmers in northern Tanzania depend on insect-pollinated crops for household food and income, and to what extent farmers are aware of the importance of insect pollinators and how they can conserve them. Our results show that local farmers in northern Tanzania derived their food and income from a wide range of crop plants, and that 67% of these crops depend on animal pollination to a moderate to essential degree. We also found that watermelon—for which pollination by insects is essential for yield—on average contributed nearly 25% of household income, and that watermelons were grown by 63% of the farmers. Our findings indicate that local farmers can increase their yields from animal pollinated crops by adopting more pollinator-friendly farming practices. Yet, we found that local farmers’ awareness of pollinators, and the ecosystem service they provide, was extremely low, and intentional actions to conserve or manage them were generally lacking. We therefore urge agriculture authorities in Tanzania to act to ensure that local farmers become aware of insect pollinators and their important role in agriculture production.

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Agricultural practices to improve yields in small‐scale farms in Africa usually focus on improving growing conditions for the crops by applying fertilizers, irrigation, and/or pesticides. This may, however, have limited effect on yield if the availability of effective pollinators is too low. In this study, we established an experiment to test whether soil fertility, soil moisture, and/or pollination was limiting watermelon (Citrullus lanatus) yields in Northern Tanzania. We subjected the experimental field to common farming practices while we treated selected plants with extrafertilizer applications, increased irrigation and/or extra pollination in a three‐way factorial experiment. One week before harvest, we assessed yield from each plant, quantified as the number of mature fruits and their weights. We also assessed fruit shape since this may affect the market price. For the first fruit ripening on each plant, we also assessed sugar content (brix) and flesh color as measures of fruit quality for human consumption. Extra pollination significantly increased the probability of a plant producing a second fruit of a size the farmer could sell at the market, and also the fruit sugar content, whereas additional fertilizer applications or increased irrigation did not improve yields. In addition, we did not find significant effects of increased fertilizer or watering on fruit sugar, weight, or color. We concluded that, insufficient pollination is limiting watermelon yields in our experiment and we suggest that this may be a common situation in sub‐Saharan Africa. It is therefore critically important that small‐scale farmers understand the role of pollinators and understand their importance for agricultural production. Agricultural policies to improve yields in developing countries should therefore also include measures to improve pollination services by giving education and advisory services to farmers on how to develop pollinator‐friendly habitats in agricultural landscapes.

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Key words: Psittaciformes, CITES, Appendix I parrots, Status and trade assessment, Norwegian Scientific Committee for Food and Environment, Norwegian Environment Agency, VKM Background: Parrots are one of the most species-rich groups of birds of which the majority inhabits tropical and subtropical forests. Nearly one-third of parrots are threatened with extinction (IUCN categories CR, EN or VU) and more than half of the world’s parrot species are assumed to be decreasing in numbers. Parrots are popular pets on all continents, mainly due to their colourful feathers, their capacity to mimic the human voice, and their tolerance to life in captivity. More than 250 species have been traded internationally. Since the inception of CITES in 1975, trade of about 12 million live wild-sourced parrots has been registered. Currently, 55 parrot species are listed on CITES Appendix I (Norwegian CITES regulation list A) that includes the most endangered among CITES-listed animals and plants. In compliance with CITES, Norway only permits import for commercial purposes of Appendix I listed parrots bred in captivity in operations included in the Secretariat's Register (Resolution Conf. 12.10 (Rev. CoP15). Presently, 9 of the Appendix I parrot species are bred in such facilities. Import of Appendix I species to Norway requires permits both from the exporter’s CITES authority and the Norwegian Environment Agency (Norwegian CITES Management Authority). All legal transactions of CITES Appendix I listed species should be recorded in the UNEP World Conservation Monitoring Centre (UNEP-WCMC) Trade Database. However, discrepancies are common, demonstrating that the trade monitoring is not accurate. Moreover, several studies suggest that regardless of efforts to regulate trade, the global conservation situation for parrots may be worse than estimated by the IUCN species statuses. Even though habitat loss is the main threat to most parrot species, it has been suggested that priority should be given to conservation actions aimed at reducing the illegal capture of wild parrots for the pet trade. As Norway’s CITES Scientific Authority, the Norwegian Scientific Committee for Food and Environment (VKM) was assigned by the Norwegian Environment Agency to assess the status of populations and trade for Appendix I parrot species. Methods: As different trade patterns are typical for different geographic regions, the species were initially divided into three groups: Africa, Australasia and Central and South America. For species with commercial trade registered in the UNEP-WCMC trade database after year 2010 a full assessment was made. In addition, two species for which negative impact from illegal trade is suspected were also fully assessed. The assessments are based on the Norwegian Cites Regulation and Article III of the Convention and Resolution 16.7(Rev.CoP17). Information on the parrot species assessed in this report were gathered from the text accounts published by BirdLife International and Birds of the World as well as literature cited in the text. Results: VKM undertook full assessments of the population status and trade for 26 of the 55 CITES Appendix I species. The species assessments are presented as fact sheets. They each contain a brief summary of the species’ biology (name, taxonomy, distribution, life history, habitat and role in ecosystem), populations and trends, threats and conservation status, population surveillance and regulations, evaluation of legal/illegal trapping and trade, overall assessment of data quality and references. We found that the quantity, as well as quality, of the information available for the Appendix I parrot species varied much. This was the case for data on general biology, population size and trends and levels of illegal trade. For all of the 23 of species for which commercial trade was registered since 2010 in the UNEP-WCMC trade database discrepancies ........

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Denne rapporten presenterer naturtypekartlegging og verdisetting av naturtyper spesielt med hensyn til myr og kystlynghei innen planområdet Nylandet ved Rørvik i Vikna kommune, Trøndelag fylke, på oppdrag fra Vikna kommune.