Pathways of introduction of alien species in Norway: analyses of an exhaustive dataset to prioritise management efforts

1. Alien species constitute one of the major threats to global biodiversity. Stopping alien species at an early stage, preferably before establishment, is crucial for the effectiveness of management actions. To enable early detection and prevent future introductions, knowledge of pathways of introduction and their absolute and relative importance is crucial. 2. Based on an exhaustive impact assessment of alien species in Norway (all multicellular neobiota), the relations of taxonomy, lifestyle and ecological impact of alien species to their pathways of introduction are investigated. This taxonomically and ecologically unbiased dataset contains 2267 unique pathways of 1180 alien species. 3. Ecological and taxonomic patterns indicate that terrestrial organisms were predominantly introduced by means of escape (mainly perennial plants escaped from gardens), parasites as contaminants (mainly fungi and insects parasitising plants), freshwater organisms by release (mainly vertebrates) and marine organisms as stowaways (mainly invertebrates and algae). Unaided introductions were most common among insects and marine organisms. 4. Alien species with high ecological impact were mainly introduced along the same pathways as other alien species. In relative terms, high-impact species were overrepresented among released species, even though this pathway was subordinate in absolute terms. The number of pathways and the overall introduction pressure were important predictors of ecological impact, especially of the species' invasion potential, and area of occupancy. 5. Introduction rates of novel alien species have seen recent increases in all taxa and along almost all pathways. This acceleration was especially pronounced for insects and fungi introduced as contaminants and for marine organisms introduced as stowaways. In absolute terms, introduction rates were highest for plant escapes, reaching more than five novel species per year. 6. Synthesis and applications. Introductions of new alien species cannot be prevented by closing one or two introduction pathways, since none can be singled out as the main pathway of high-impact alien species. Yet each pathways closedmakes a difference, as this reduces the overall introduction pressure. The highest priorities for management are the pathways that are easiest to address, such as release, and those with the highest volumes, such as plant trade. ecological impact, escape, introduction pathway, invasive species, spread, stowawaypublishedVersio

Phenotypic plasticity masks range-wide genetic differentiation for vegetative but not reproductive traits in a short-lived plant

Genetic differentiation and phenotypic plasticity jointly shape intraspecific trait variation, but their roles differ among traits. In short-lived plants, reproductive traits may be more genetically determined due to their impact on fitness, whereas vegetative traits may show higher plasticity to buffer short-term perturbations. Combining a multi-treatment greenhouse experiment with observational field data throughout the range of a widespread short-lived herb, Plantago lanceolata, we (1) disentangled genetic and plastic responses of functional traits to a set of environmental drivers and (2) assessed how genetic differentiation and plasticity shape observational trait-environment relationships. Reproductive traits showed distinct genetic differentiation that largely determined observational patterns, but only when correcting traits for differences in biomass. Vegetative traits showed higher plasticity and opposite genetic and plastic responses, masking the genetic component underlying field-observed trait variation. Our study suggests that genetic differentiation may be inferred from observational data only for the traits most closely related to fitness

Phenotypic plasticity masks range-wide genetic differentiation for vegetative but not reproductive traits in a short-lived plant

Publication history: Accepted - 19 May 2021; Published - 5 August 2021.Genetic differentiation and phenotypic plasticity jointly shape intraspecific trait variation, but their roles differ among traits. In short-lived plants, reproductive traits may be more genetically determined due to their impact on fitness, whereas vegetative traits may show higher plasticity to buffer short-term perturbations. Combining a multi-treatment greenhouse experiment with observational field data throughout the range of a widespread short-lived herb, Plantago lanceolata, we (1) disentangled genetic and plastic responses of functional traits to a set of environmental drivers and (2) assessed how genetic differentiation and plasticity shape observational trait–environment relationships. Reproductive traits showed distinct genetic differentiation that largely determined observational patterns, but only when correcting traits for differences in biomass. Vegetative traits showed higher plasticity and opposite genetic and plastic responses, masking the genetic component underlying field-observed trait variation. Our study suggests that genetic differentiation may be inferred from observational data only for the traits most closely related to fitness.Eesti Teadusagentuur, Grant/Award Number: PRG609 and PUT1409; Academy of Finland; Natural Sciences and Engineering Research Council of Canada; Science Foundation Ireland, Grant/Award Number: 15/ERCD/2803; Spanish Ministry of Science, Innovation and Universities, Grant/Award Number: IJCI-2017- 32039; European Regional Development Fun

Predicting and assessing climate-change impacts on the population dynamics of alpine and lowland forbs

Background and aims: Global climate change is already affecting plant species worldwide. The global rise in temperatures and regional changes in precipitation are predicted to continue throughout the century. Therefore, studying how climate affects species performance is crucial for understanding the implications that future changes may hold for plants. Recently, there have been several calls for studies addressing the complexities of climate change impacts, by for instance combining and integrating spatial gradient approaches, time-series data, and experiments. Another important challenge is to incorporate precipitation change and its interaction with temperature increase, since the nature of these interactions (positive, negative, additive, non-additive) determines the net effect of the combined change. Moreover, climate change affects plants not only directly, through physiological constraints, but also indirectly, through changes in biotic interactions. Disentangling these biotic interactions is crucial for understanding and predicting climate change impacts. Finally, a need for investigating plant population dynamics is needed to gain a better understanding of how and why plants respond to climatic changes on the population, species and community level. In this thesis I examine the combined effects of changes in temperature and precipitation on the population dynamics of sub-dominant forb species. I investigate climate control on the study species both along climatic gradients in space and time, and in turf- and seed-transplant experiments along climatic gradients. To assess the effect of biotic interactions along spatial climatic gradients, I use a removal experiment. Study area and species: The studies presented in this thesis were performed in the fjord-and-mountain landscape of Western Norway. The steep climatic gradients in this area enable the establishment of a ‘climatic grid’ comprising of 12 sites in three levels of temperature and four levels of precipitation. The study species were two alpine / lowland species pairs, Veronica alpina / officinalis and Viola biflora / palustris, which were relatively common and representative for the forb communities at the study sites. The study area includes the rear altitudinal range edge of the two alpine species and the leading altitudinal range edge of the two lowland species. Main findings: All species were under strong climate control. Warmer temperatures had mainly negative effects on both population growth rates and seedling establishment, while precipitation increase had more varying effects with some positive impacts on the Viola species and mainly negative effects on the Veronica species. Seedling establishment increased with increasing precipitation. The effects of temperature and precipitation change were generally not additive in the combined treatment, they either cancelled each other out, or stayed at the level of one of the single-factor effects. The biotic interaction experiment revealed a shift from facilitation to competition as temperature increases, but no overall pattern for precipitation. This suggests that the negative impacts of a warmer and a warmer+wetter climate found in the other studies may be related to changes in biotic interactions, whereas the responses to precipitation may reflect more direct effects. The results were independent of the species’ alpine or lowland habitat affinities, suggesting that also lowland species will and already do face challenges under climate change. In fact, the studies in this thesis, when taken together, indicate that Veronica officinalis already may be on the move upwards, potentially being pushed out of its historic range by increased competition under climatic warming. In conclusion, this thesis highlights the benefits of including higher complexity in ecological climate change research through ‘integrated studies’ that allow for (1) detecting climate control on species where single approaches fail, and (2) revealing underlying mechanisms and time scales for the found effects

Pathways of introduction of alien species in Norway: analyses of an exhaustive dataset to prioritise management efforts

1. Alien species constitute one of the major threats to global biodiversity. Stopping alien species at an early stage, preferably before establishment, is crucial for the effectiveness of management actions. To enable early detection and prevent future introductions, knowledge of pathways of introduction and their absolute and relative importance is crucial. 2. Based on an exhaustive impact assessment of alien species in Norway (all multicellular neobiota), the relations of taxonomy, lifestyle and ecological impact of alien species to their pathways of introduction are investigated. This taxonomically and ecologically unbiased dataset contains 2267 unique pathways of 1180 alien species. 3. Ecological and taxonomic patterns indicate that terrestrial organisms were predominantly introduced by means of escape (mainly perennial plants escaped from gardens), parasites as contaminants (mainly fungi and insects parasitising plants), freshwater organisms by release (mainly vertebrates) and marine organisms as stowaways (mainly invertebrates and algae). Unaided introductions were most common among insects and marine organisms. 4. Alien species with high ecological impact were mainly introduced along the same pathways as other alien species. In relative terms, high-impact species were overrepresented among released species, even though this pathway was subordinate in absolute terms. The number of pathways and the overall introduction pressure were important predictors of ecological impact, especially of the species' invasion potential, and area of occupancy. 5. Introduction rates of novel alien species have seen recent increases in all taxa and along almost all pathways. This acceleration was especially pronounced for insects and fungi introduced as contaminants and for marine organisms introduced as stowaways. In absolute terms, introduction rates were highest for plant escapes, reaching more than five novel species per year. 6. Synthesis and applications. Introductions of new alien species cannot be prevented by closing one or two introduction pathways, since none can be singled out as the main pathway of high-impact alien species. Yet each pathways closedmakes a difference, as this reduces the overall introduction pressure. The highest priorities for management are the pathways that are easiest to address, such as release, and those with the highest volumes, such as plant trade. ecological impact, escape, introduction pathway, invasive species, spread, stowawa

Miljøovervåkingsprogram for Ormen Lange landanlegg – Nyhamna, Gossa. Overvåking av vegetasjon og jord – endringer fra 2008 til 2016

Aarrestad, P.A., Bakkestuen, V., Stabbetorp, O.E. & Töpper. J.P. 2017. Miljøovervåkingsprogram for Ormen Lange landanlegg – Nyhamna, Gossa. Overvåking av vegetasjon og jord – endringer fra 2008 til 2016. - NINA Rapport 1348. 42 s. Ormen Lange landanlegg på øya Gossa i Aukra kommune mottar ubehandlet gass og lettolje (kondensat) fra Ormen Lange-feltet i Norskehavet. Ved produksjon av salgsgass og kondensat slipper landanlegget ut CO, CO2, NOx, CH4, NMVOC (inklusive BTEX), SO2 og mindre mengder tungmetaller etter utslippstillatelse gitt av Miljødirektoratet. Prosessanlegget ble ferdigstilt for drift i 2007 med A/S Norske Shell er operatør. Utslipp av nitrogen og svovelholdige gasser kan generelt påvirke terrestriske økosystemer ved forsuring og gjødsling av jordsmonn og vegetasjon. Utslippene fra landanlegget ble ved oppstart beregnet til å ligge under gjeldende kritiske tålegrenseverdier for terrestriske naturtyper, men tålegrenseverdiene i influensområdet ligger nær overskridelsestersklene. For å kunne dokumentere eventuelle effekter av utslipp til luft av forurensende stoffer, ble det i 2008 etablert en overvåking av vegetasjon og jord i influensområdet fra Ormen Lange landanlegg. Overvåkingen er videreført med noen justeringer i metodikk siden oppstart. Det er opprettet to overvåkingsområder, ett med relativt høy avsetning av nitrogen nord for anlegget innenfor Gule-Stavikmyrane naturreservat i Fræna kommune (lokalitet Gulmyran), og ett sør for landanlegget på øya Gossa (lokalitet Aukra), med lavere estimert avsetning fra anlegget. Innen hvert område utføres en integrert overvåking av vegetasjonens artssammensetning, plantevekst og kjemisk innhold i planter og jord og jordvann i tre ulike næringsfattige vegetasjonstyper: 1) tørr røsslynghei, 2) tuemyr og 3) fastmattemyr, begge de to siste på nedbørsmyr. Disse vegetasjonstypene anses for å ha lave tålegrenser for forurensing, og er følsomme for forsuring og eutrofiering. Fra oppstart av anlegget i 2008 har det skjedd relativt små endringer i vegetasjonens artssammensetning på begge lokaliteter, bortsett fra en svak økning av graminidene torvull og duskull, samt en svak tilbakegang av lavarter og mosene heigråmose og heiflette. I tillegg har vi registrert en betydelig tilbakegang av røsslyng, både i røsslynghei og fastmattemyr, noe som skyldes klima. Vinterfrost de senere årene, kombinert med sterk vind som tørker ut planten, har ført til sterk avdøing av planten. Økningen av graminider og tilbakegangen av lav kan imidlertid indikere en begynnende eutrofiering fra utslipp og avsetninger av nitrogen. Vegetasjonsanalysene viser også at røsslyngheia og tuemyrene har endret karakter mot noe fuktigere plantesamfunn. Dette er trolig et resultat av klimatisk påvirkning og naturlige prosesser i myrsystemene, og det er således lite sannsynlig at disse endringene skyldes utslipp til luft fra Ormen Lange landanlegg. Resultatene viser ikke entydige forskjeller i endringer i vegetasjonens artssammensetning mellom de to områdene siden oppstart. Dette kan enten skyldes at nedfallet fra anlegget ikke er vesentlig forskjellig i de to områdene, eller at annen luftforurensning har større betydning enn nedfallet fra Ormen Lange landanlegg. De kjemiske analysene av jord, jordvann og plantevev viser verdier som generelt indikerer næringsfattige og lite forurensede områder, og de fleste overvåkingsparametere viser ingen signifikante endringer over tid. Det er imidlertid en svak tendens til forsuring av jordvann på begge lokaliteter. Humusjorden blir også svakt surere på begge lokaliteter, men det er ingen tegn til nitrogeneutrofiering av jordsmonnet. Kvikksølv viser en svak økning i jord på lokaliteten Aukra, og mengden kvikksølv i jordvann har økt betydelig etter oppstart av prosessanlegget på begge lokaliteter. De målte konsentrasjonene alle år etter oppstart er høyere enn den gjennomsnittlige årlige konsentrasjonen av kvikksølv i nedbør i Norge. Tungmetallet nikkel øker også både i jord og jordvann. Økningen av kvikksølv og nikkel i jord og jordvann etter oppstart av prosessanlegget, er således noe bekymringsfullt. Nivåene av tungmetaller i planter ligger omtrent på samme nivå som ikke-forurensede områder i Norge. Det er imidlertid en svak økning av tungmetaller som kvikksølv, nikkel og titan i heigrå-mose og lys reinlav. De fleste endringene skjer på begge lokaliteter, og siden begge lokaliteter er påvirket av nedfall fra anlegget, kan man ikke se bort ifra at økningen kan skyldes utslipp fra Ormen Lange landanlegg. Endringene siden oppstart må likevel sies å være marginale i begge områdene. Lokalitet Aukra er siden 2008 blitt sterkt påvirket av beite fra hjortedyr og noe endring i dreneringsmønster. Det er også usikkert om lokaliteten virkelig har mindre nedfall av forurensede stoffer fra bedriften enn lokalitet Gulmyran, og andre forurensningskilder kan finnes i nærområdet til lokalitet Aukra. De ulike påvirkningene og usikkerheten i deposisjonsdata vanskeliggjør klare tolkninger av datamaterialet. Vi anbefaler derfor å legge ned lokalitet Aukra og heller opprette en ny referanselokalitet lenger sør, helt uten påvirkning fra anlegget. Samtidig bør man overveie å måle de reelle avsetninger av nitrogen, surhet og tungmetaller i nedbør på begge lokaliteter.Aarrestad, P.A., Bakkestuen, V., Stabbetorp, O.E. & Töpper. J.P. 2017. The environmental monitoring program for the Ormen Lange Onshore Processing Plant – Nyhamna, Gossa. Monitoring of vegetation and soil – changes from 2008 to 2016. – NINA Report 1348. 42 pp. The Ormen Lange Onshore Processing Plant in Aukra municipality (Møre and Romsdal county) receives unprocessed gas and condensate from the Ormen Lange field in the Norwegian Sea. During processing of sales gas and condensate, the plant emits CO, CO2, NOx, CH4, NMVOC (including BTEX), SO2 and small amount of heavy metals, as specified in the discharge permit issued by Norwegian Environment Agency. The plant started production in 2007, with A/S Norske Shell as operator. In general, emissions of nitrogen- and sulfur containing gasses may affect terrestrial ecosystems through acidification and fertilization of soil and vegetation. The emissions from the onshore plant are estimated to be low. However, the nitrogen background level in the influenced area is close to the critical loads of nitrogen for oligotrophic habitats. To be able to document any effects of emissions to air on terrestrial ecosystems, a monitoring program for vegetation and soil was established in 2008. The monitoring has been continued with certain adjustments in methodology until 2016. In 2008 two monitoring sites were established, one with rather high deposition of nitrogen north of the plant within the Gule-Stavmyrane nature reserve in Fræna municipality (site Gulmyran) and one south of the plant on the island Gossa (site Aukra) with estimated deposition levels somewhat lower than Gulmyran. Within each site, integrated monitoring of the species composition of the vegetation and chemical content of plants, soil and ground water are conducted for three distinct nutrient-poor vegetation types: 1) dry oligotrophic Calluna vulgaris dominated heathland, 2) hummocks and 3) wet oligotrophic lawns, both on raised bogs. These types of vegetation are considered to have low critical loads for air pollution, i.e. they are sensitive to both acidification and eutrophication. Since the start of the plant in 2008, there have been minor changes in the species composition of the vegetation at both sites, except for a strong decline in the cover of Calluna vulgaris, a slight increase in graminoids of Eriophorum vaginatum and E. angustifolium as well as a slight decline in lichens and mosses, such as Racomitrium lanuginosum and Hypnum jutlandicum. The significant decline in Calluna, both on heathland and hummocks, is caused by the degeneration of the plant due to winter frost in recent years, combined with intense winds, which dries out the heather, while increases in graminoids and decline of lichens and bryophytes may indicate an early eutrophication stage from nitrogen depositions. The vegetation analyses also show that the Calluna heath and the hummocks have changed their character into somewhat more moist plant communities. This is probably a result of climatic influence and natural processes occurring in the bog ecosystem, and it is unlikely that these changes are due to emissions to air from the Ormen Lange Onshore Processing Plant. The results of the vegetation analyses do not show unequal differences between the two sites since start-up of the plant. This could indicate that the deposition of air pollution at the two sites is not significantly different, or that impact from other air pollution is more important than the deposition from the plant. In general, the chemical analyses of soil, soil water and plant tissue show values that indicate nutrient-poor and less polluted sites, and most monitored parameters show no significant changes over time. However, there is a slight tendency for acidification of soil water at both sites. Soil humus also becomes weakly more acidic at both sites, but there are no signs of N-eutrophication of the soil. There is a slight increase in mercury content in the soil from the Aukra site, and mercury in groundwater has increased significantly after the start of the processing plant at both sites. The concentrations in soil water are higher than the average annual concentration value in the precipitation of Norway. Also, the content of nickel increases in soil and soil water. The increase of mercury and nickel in soil and groundwater after the start of the processing plant, is thus somewhat worrying. The levels of heavy metals in plants are approximately the same as in non-polluted areas in Norway. There is, however, a slight increase in heavy metals (mercury, nickel and titan) in Raco-mitrium lanuginosum and lichens from 2008 to 2016. Most changes occur at both sites, and since both sites are affected by deposition from the plant, one cannot ignore that the changes in plant tissue chemistry may be due to emissions from the plant. However, the changes since start-up are marginal in both areas. The site Aukra has been heavily affected by grazing and trampling by deer and some change in drainage since 2008 that may have affected the results from this site. In addition, one might raise the question if this site really has less deposition of air pollution emitted from the Ormen Lange Onshore Processing Plant, than the site Gulmyran. There may also be other sources of air pollution near the plant. The external impacts and the uncertainty in deposition complicates clear interpretations of the data. We therefore recommend to close down the Aura site, and instead create a new reference site completely without impact from the plant. One should also consider measuring the deposition of air pollution at both sites

Plastic Population Effects and Conservative Leaf Traits in a Reciprocal Transplant Experiment Simulating Climate Warming in the Himalayas

Climate warming poses considerable challenges for alpine plant species, especially for competitively inferior ones with resource-conservative adaptations to cold climates. The Himalayas are warming at rates considerably faster than the global average, so it is particularly important to assess how and through which mechanisms alpine plant species are affected there. We employed a demographic approach in a climate change experiment, where vegetation turfs were transplanted reciprocally between the central parts of the study species’ (Viola biflora L. var. rockiana) range and the warmer range margin, with a temperature difference of ca. 1°C. In addition, turfs were also transplanted outside the range to warmer habitats, simulating two different scenarios of climate warming, +1 and +4°C. Transplanting to warmer sites negatively impacted population growth rates (λ), survival and clonality, but did not affect growth and fecundity, while the productivity of the plant community increased. The reciprocal transplants to the colder habitat showed the opposite effects, for both V. biflora and the plant community, indicating plastic responses of the study species, driven by changes in plant–plant competition. However, the leaf traits underlying the modeled population growth rates were origin-site specific and not affected by the climate-change treatments over the study period, suggesting local adaptation of growth form to competition in the warmer range margin, and to climate adversity in the colder range center. The transplants outside the present species’ range showed consistently stronger reductions in population growth rate and survival, with mortality of 90–100% in the +4°C treatment. This illustrates that climatic changes beyond species’ present climatic ranges pose a serious risk for range contraction and extinction for Himalayan alpine species in the near future. As V. biflora seems mostly limited by competition under warming, its persistence in a future climate may become increasingly dependent on keeping competitive effects from the surrounding community low, for instance by management interventions like grazing and mowing