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Forestry history in boreal production and near-natural forest – impacts on biodiversity in wood-inhabiting fungi
Get PDFSince the 1940s, stand-based forest management, including clear-cutting, has been the predominant practice in Norway, with approximately 60% of Norwegian forests having undergone at least one cycle of clear-cutting. This forestry practice has led to a significant loss of natural forest structure and coarse dead wood, which are crucial for maintaining natural, ecological processes. Wood-inhabiting fungi (saproxylic fungi) play an important role in forest ecosystems. They decompose dead wood and contribute to nutrient cycling, while their diversity and abundance may give an indication of the forest's biodiversity status.
This thesis aims to investigate the impacts of historical logging activities on the biodiversity of wood-inhabiting fungi in boreal forests, comparing mature forests that previously have been clear-cut with near-natural forests. The field study involved conducting surveys in 12 pairs of forest sites. Each pair consisted of an old, near-natural forest (NN) and a mature production forest established through clear-cutting (CC). All sites were situated in south-eastern Norway and represented bilberry-type spruce-dominated forest. The surveys included registering the number of cut stumps and coring of living trees, supported by pre-existing datasets on dead wood and biodiversity.
Near-natural forests had significantly higher species richness of wood-inhabiting fungi compared to previously clear-cut forests. The study also explored the correlation between volume and diversity of dead wood and biodiversity, confirming that greater volumes and diversity of dead wood were associated with higher species richness. Red-listed species were predominantly found in the near-natural forests. No statistical evidence directly linked management type to species composition, although a pattern suggesting a potential effect of management type was observed. These results offer valuable insights for forest management practices, highlighting the importance of preserving natural forest structures, especially dead wood, to enhance biodiversity
Long-term effects of timber harvest on cavity-nesting birds in Norwegian boreal forests
Get PDFFennoscandia is primarily covered in forests, but modern forestry has dramatically altered the landscape. Mixed-species and uneven-aged forests with natural gap rotations of 250 years were replaced by dense, even-aged stands that are clearcut every 80-120 years. Only 1.7% of
productive boreal forest has never been clearcut in Norway, creating a patchwork of stands homogenized in structure, age, and composition. This transformation has removed niches and degraded habitats for myriad forest-dependent species. Deadwood- and cavity-dependent
birds, insects, lichens, plants, and other taxa have been disproportionately threatened by the removal of standing dead trees (snags) in harvests and thinnings. Many cavity-nesting birds
(hereafter cavity-nesters) have been deprived of their primary nesting and foraging cover.
I used a quasi-experimental approach to quantify changes in habitat variables and bird activity. Acoustic recorders were placed in 10 locations throughout southeastern Norway from 6 June to 22 July 2023. Each location contained a pair of forest sites – one that had been
clearcut 40-80 years ago (CC) and one that had never been clearcut (NN). These sites are part of the EcoForest project (https://ecoforest.no/), a collaborative effort to study long-term changes in forest biodiversity caused by past forest management.
Automated analysis of all 3,026 h of audio recordings using BirdNET detected 169 bird species (<165 after validation). Neither total species richness nor Shannon diversity was higher in either SiteType (CC or NN), but diversity was more variable in NN. Far more recordings per day per site of excavators and old-growth icons were recorded in NN, while
significant, marginally higher numbers were found for weak excavators and secondary nesters in CC. A declining keystone species, Picoides tridactylus, and an apex predator, Accipiter gentilis, were 7 and 9 times more frequently detected in NN, respectively.
NN had 1 more cavity per habitat survey plot (14/ha), habitat trees measuring 8 cm DBH larger on average, at least twice the total deadwood volume of CC, and trees with longer crowns. The homogenous conditions and scarcity of deadwood resources and cavities in CC likely prevent the recovery of numerous forest species. Management Recommendations: Converting up to half of even-aged to uneven-aged forestry to produce a true mosaic landscape of intensive plantations, extensive forests, and preserves will bolster resilience in
populations, ecosystems, and the timber industry
Predicting the status of sediment ecosystems around commercial fish farms from taxonomic and functional profiles
Get PDFThe sediments around commercial fish farms are regularly monitored regarding the
environmental condition. If the environmental condition is not sufficient, a quarantine period is
imposed on the fish farms. It is therefore important that the environmental state is mapped
quickly and with good precision. Currently, this is determined manually from inspection of
sediment samples by expert taxonomists, who determine an environmental index based on
macrofauna. The AQUAeD project (2021-2025) – On-site monitoring of aquaculture impact on
the environment by open-source nanopore eDNA analysis – aims to replace the current
environmental monitoring analyses with digital DNA based solutions, as well as moving the
analyses to the facilities to achieve fast and accurate results.
This thesis is a part of the AQUAeD project, and the data used was from 16S sequencing. From
the 16S data, taxonomic profiles can be made, and the essential aim of this thesis is to predict
the ecosystem status from this. However, the taxonomic diversity present in sediments is
significant, with numerous organisms being unidentified and lacking names within the existing
taxonomy. From the metagenome data, functional profiles can be derived. This entails coding
genes and categorizing them into functional groups such as EC functions, KO functions and
MetaCyc pathways. Then functional profiles can be constructed accordingly.
An indicator of the ecosystem status is the nEQR values, which is what has been predicted in
this thesis for both the taxonomic and functional profiles. The results from this shows that the
predictions are good for both taxonomic and functional profiles, but also that the functional
profiles do not give better predictions. Rather, they are very similar to each other.
In this thesis, AI (Artificial Intelligence) was used to assist with the coding, as well as finding
sources for the background information in the introduction of this thesis. The AI instruments
used in this thesis was ChatGPT and Perplexity.
Sedimentene rundt kommersielle fiskeoppdrettsanlegg blir jevnlig overvåket med tanke på
miljøtilstanden. Hvis miljøtilstanden ikke er tilstrekkelig, blir det pålagt karantenetid for
oppdrettsanleggene. Det er derfor viktig at miljøtilstanden kartlegges raskt og med god
presisjon. For øyeblikket blir dette bestemt gjennom inspeksjon av sedimentprøver utført av
eksperter på taksonomi, som fastsetter en miljøindeks basert på makrofauna. AQUAeDprosjektet (2021-2025) – Overvåkning av akvakulturens påvirkning på miljøet ved hjelp av
open source for nanopore eDNA analyse – har som mål å erstatte de nåværende
miljøovervåkningsanalysene med digitale DNA-baserte løsninger, samt å flytte analysene til
fiskeoppdrettsanleggene for å oppnå raske og nøyaktige resultater.
Denne avhandlingen er en del av AQUAeD-prosjekter, og dataene som ble brukt var fra 16S
sekvensering. Fra 16S dataene kan det lages taksonomiske profiler, og det essensielle målet
med denne avhandlingen er å forutsi økosystemets tilstand fra dette. Den taksonomiske
mangfoldigheten i sedimentene er derimot betydelig, med mange organismer som ikke er
identifisert og som mangler navn innenfor den eksisterende taksonomien. Fra metagenomdataene kan funksjonelle profiler utledes. Dette innebærer kodende gener og kategorisering av
dem i funksjonelle grupper som EC funksjoner, KO funksjoner og MetaCyc pathways. Videre
kan funksjonelle grupper konstrueres.
En indikator på økosystemets tilstand er nEQR-verdier, som er det som har blitt predikert i
denne avhandlingen for både de taksonomiske og funksjonelle profilene. Resultatene fra dette
viser at prediksjonene er gode for både taksonomiske og funksjonelle profiler, men de
funksjonelle profilene gir heller ikke bedre prediksjoner. Tvert imot er de veldig like hverandre.
I denne avhandlingen ble KI (Kunstig Intelligens) brukt til å hjelpe med kodingen, samt å finne
kilder til bakgrunnsinformasjonen i innledningen til denne avhandlingen. KI-instrumentene
som ble brukt i denne avhandlingen var ChatGPT og Perplexity
Can policy packaging help overcome Pigouvian tax aversion? A lab experiment on combining taxes and subsidies
No full textTax aversion makes it politically challenging to introduce Pigouvian taxes. One proposed solution to overcome this resistance is to package policies. Using an online lab experiment, we investigate whether combining a tax and a subsidy is perceived as more acceptable than the tax or the subsidy alone. The purpose of the policies is to reduce demand for a good with a negative externality to the socially optimal level. We find that support for a combination of a tax and a subsidy equals the simple average of support for the two instruments alone. Combining a tax and a subsidy therefore does not reduce tax aversion. We examine potential mechanisms behind the tax aversion. Participants believe they will receive a lower share of the tax revenue when the tax is implemented alone than when it is combined with a subsidy, i.e. the participants in the tax alone group hold more pessimistic beliefs about the tax revenue. We also find that the participants expect the tax to be more effective in reducing demand for the good with a negative externality than both the subsidy alone and the combinations of tax and subsidy. This belief does not, however, translate into support for the tax.Can policy packaging help overcome Pigouvian tax aversion? A lab experiment on combining taxes and subsidiespublishedVersionpublishedVersio
Betydning av lagring av melk på kvalitetsegenskaper til ferskost
Get PDFPseudomonas spp. er en av de mest tallrike bakterieslektene som finnes i rå melk. Dette er
psykrotrofe bakterie som betyr at de kan vokse ved lave temperaturer (<7°), og overlever derfor
kjølelagring av melk. Disse bakteriene kan produsere termostabile ekstracellulære proteinaser.
Slike enzymer kan hydrolysere proteinene i melken som kan føre til kvalitetsødeleggelse og
redusert holdbarhet av melk og meieriprodukter. Det er derfor hensiktsmessig å kartlegge
hvordan en slik proteolytisk aktivitet påvirker kvalitetsegenskaper til meieriprodukter.
I denne studien ble det undersøkt hvordan lagring av rå melk og vekst av psykrotrofe bakterier
påvirket kvalitetsegenskaper til ferskost. Dette ble gjort ved å yste ferskost av fersk melk og av
melk som var lagret i 3 dager. Det ble også ystet ferskost av melk som var tilsatt log 3 kde/mL
Pseudomonas spp. Ystemelkens bakterievekst, kjemiske sammensetning, innhold av organiske
syrer og karbohydrater, og innhold av flyktige aromakomponenter ble analysert. For ferskost
ble det også gjennomført mikrobiologisk analyse, samt en rekke kjemiske og reologiske
analyser. Proteinsammensetningen i myse fra ferskost ble også analysert. Det ble også
gjennomført en sensorisk profilering for å kartlegge smaksprofilen til ferskost. I forkant av
forsøket ble det gjennomført prøveystinger for å standardisere forbehandlingen av ystemelken.
Resultatene viste at lagring av ystemelk hadde størst effekt på kvalitetsegenskapene til ferskost.
Lagring av rå ystemelk kan tett knyttes til en økning av psykrotrofe bakterier og proteolytisk
aktivitet. I denne studien ledet lagring til en økning fra ~ log 3 kde/mL til ~ log 6 kde/mL
psykrotrofe bakterier i rå ystemelk, noe som hadde konsekvenser for ferskost ystet av denne
melken. Ystemelkens lagringstid hadde ingen effekt på det totale proteininnholdet i ferskost,
men det påvirket proteinsammensetningen. Det ble funnet en større konsentrasjon αs1-kasein i
ferskost ystet av lagret melk enn i ferskost ystet av fersk melk, mens konsentrasjonen av βkasein i ferskost ble ikke påvirket. Lagring av ystemelk førte også til et lavere innhold av
laktose og glukose, samt redusert produksjon av acetaldehyd i ferskost. Sensorisk profilering
av ferskost viste at lagring av ystemelken hadde ingen effekt på den sensoriske oppfatningen
av produktet.Pseudomonas spp. is one of the most abundant genera of bacteria found in raw milk. These are
psychotropic bacterium which means that they can grow at low temperatures (<7°) and
therefore survive cold storage of milk. These bacteria can produce thermostable extracellular
proteinases. Such enzymes can hydrolyse the proteins in the milk which can lead to quality
destruction and reduced shelf life of milk and dairy products. It is therefore of interest to map
how such proteolytic activity affects the quality properties of dairy products.
In this study, it was investigated how the storage of raw milk, and the growth of psychotropic
bacteria affected the quality properties of fresh cheese. This was done by making fresh cheese
from fresh milk and from milk that had been stored for 3 days. Fresh cheese was also made
from milk to which log 3 kde/mL Pseudomonas spp had been added. The cheese milk’s
bacterial growth, chemical composition, content of organic acids and carbohydrates, and
content of volatile aroma components were analysed. For fresh cheese, microbiological
analysis was also carried out, as well as a number of chemical and rheological analyses. The
protein composition in whey from fresh cheese was also analysed. Sensory profiling was also
carried out to map the tasting profile of fresh cheese. Ahead of the experiment, the cheese
making process was tested to standardize the pre-treatment of the cheese milk.
The results showed that the storage of cheese milk had the greatest effect on the quality
properties of fresh cheese. Storage of raw cheese milk can be closely linked to an increase in
psychotropic bacteria and proteolytic activity. In this study, storage led to an increase from ~
log 3 kde/mL to ~ log 6 kde/mL of the number of psychotropic bacteria in raw cheese milk,
which had consequences for fresh cheese made from this milk. The storage time of the cheese
milk had no effect on the total protein content of fresh cheese, but it did affect the protein
composition. A greater concentration of αs1-casein was found in fresh cheese made from stored
milk than in fresh cheese made from fresh milk, while the concentration of β-casein in fresh
cheese was not affected. Storage of cheese milk also led to a lower content of lactose and
glucose, as well as reduced production of acetaldehyde in fresh cheese. Sensory profiling of
fresh cheese showed that storage of the cheese milk had no effect on the sensory perception of
the product
A comprehensive transcriptional body map of Atlantic salmon unveils the vital role of the intestine in the immune system and highlights functional specialization within its compartments
Get PDFThe intestine is a barrier organ that plays an important role in the immune system of Atlantic salmon. The immune functions are distributed among the diffuse gut lymphoid tissue containing diverse immune cells, and other cell types. Comparison of intestinal transcriptomes with those of other organs and tissues offers an opportunity to elucidate the specific roles of the intestine and its relationship with other parts of the body. In this work, a meta-analysis was performed on a large volume of data obtained using a genome-wide DNA oligonucleotide microarray. The intestine ranks third by the expression level of immune genes after the spleen and head kidney. The activity of antigen presentation and innate antiviral immunity is higher in the intestine than in any other tissue. By comparing transcriptome profiles, intestine shows the greatest similarity with the gill, head kidney, spleen, epidermis, and olfactory rosette (descending order), which emphasizes the integrity of the peripheral mucosal system and its strong connections with the major lymphoid organs. T cells-specific genes dominate among the genes co-expressed in these tissues. The transcription signature of CD8+ (86 genes, r > 0.9) includes a master gene of immune tolerance foxp3 and other negative regulators. Different segments of the intestine were compared in a separate experiment, in which expression gradients along the intestine were found across several functional groups of genes. The expression of luminal and intracellular (lysosome) proteases is markedly higher in pyloric caeca and distal intestine respectively. Steroid metabolism and cytochromes P450 are highly expressed in pyloric caeca and mid intestine while the distal intestine harbors genes related to vitamin and iron metabolism. The expression of genes for antigen presenting proteins and immunoglobulins shows a gradual increase towards the distal intestine.publishedVersio
Risk assessment of inter-basin water transfer plans through integration of Fault Tree Analysis and Bayesian Network modelling approaches
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Food provisioning, diel activity, and home range size in the glaucous gull (Larus hyperboreus) on Bjørnøya
Get PDFThe glaucous gull (Larus hyperboreus) is one of the only numerous predatory bird species on Svalbard. They are generalist feeders that hunt and scavenge for food along the coast and on the open sea. On Bjørnøya, the gulls mainly feed on carrion, avian prey, and fish. In this
study, camera traps were set out on a total of nine glaucous gulls’ nests to capture images of prey delivered by the parents to their young. Some of the gulls were also fitted with Pathtrack® Nanofix + RF GPS tags that tracked their movement to study their habitat use and estimate home ranges. Fish and avian prey comprised the main part of the diet. The camera trap images showed that capelin (Mallotus villosus), guillemot (Uria sp.) chicks, and guillemot eggs were the main prey brought to the chicks. The composition of prey captured varied between nests, depending on location, with fish dominating the diet at nests situated
closer to sea level. The gulls were not found to display a clear diurnal cycle, as also observed in other populations and species breeding in the Arctic. An interesting find in this study was that all four gulls fitted with a GPS tag had very small home ranges, only extending a few square kilometers around their nest site. The gulls rarely ventured out to sea and were never recorded more than a few hundred meters from land. With up to 30% of fish in some of the gulls’ diet, this led to the question of where and how the gulls caught the fish. Combining GPS data and prey delivery data from the camera traps, it was found that the gulls found most
of the fish very close to their nest, suggesting that they mostly pirated fish from other seabirds or found shoals of fish very close to the island. To further strengthen the results in this study, more data and larger sample sizes is required, especially on the use of GPS tags in combination with camera traps, as this is still a novel data gathering method
Anticipating critical transitions in multidimensional systems driven by time- and state-dependent noise
Get PDFAnticipating bifurcation-induced transitions in dynamical systems has gained relevance in various fields of the natural, social, and economic sciences. Before the annihilation of a system's equilibrium point by means of a bifurcation, the system's internal feedbacks that stabilize the initial state weaken and eventually vanish, a process referred to as critical slowing down (CSD). In one-dimensional systems, this motivates the use of variance and lag-1 autocorrelation as indicators of CSD. However, the applicability of variance is limited to time- and state-independent driving noise, strongly constraining the generality of this CSD indicator. In multidimensional systems, the use of these indicators is often preceded by a dimension reduction in order to obtain a one-dimensional time series. Many common techniques for such an extraction of a one-dimensional time series generally incur the risk of missing CSD in practice. Here, we propose a data-driven approach based on estimating a multidimensional Langevin equation to detect local stability changes and anticipate bifurcation-induced transitions in systems with generally time- and state-dependent noise. Our approach substantially generalizes the conditions under which CSD can reliably be detected, as demonstrated in a suite of examples. In contrast to existing approaches, changes in deterministic dynamics can be clearly discriminated from changes in the driving noise using our method. This substantially reduces the risk of false or missed alarms of conventional CSD indicators in settings with time-dependent or multiplicative noise. In multidimensional systems, our method can greatly advance the understanding of the coupling between system components and can avoid risks of missing CSD due to dimension reduction, which existing approaches suffer from.Anticipating critical transitions in multidimensional systems driven by time- and state-dependent noisepublishedVersio