Anders Bryn
Forsker
(+47) 930 39 782
anders.bryn@nibio.no
Sted
Ås - Bygg O43
Besøksadresse
Oluf Thesens vei 43, 1433 Ås (Varelevering: Elizabeth Stephansens vei 21)
Biografi
Sammendrag
Purpose Treelines and forest lines (TFLs) have received growing interest in recent decades, due to their potential role as indicators of climate change. However, the understanding of TFL dynamics is challenged by the complex interactions of factors that control TFLs. The review aims to provide an overview over the trends in the elevational dynamics of TFLs in Norway since the beginning of the 20th century, to identify main challenges to explain temporal and spatial patterns in TFL dynamics, and to identify important domains for future research. Method A systematic search was performed using international and Norwegian search engines for peer-reviewed articles, scientific reports, and MA and PhD theses concerning TFL changes. Results Most articles indicate TFL rise, but with high variability. Single factors that have an impact on TFL dynamics are well understood, but knowledge gaps exist with regard to interactions and feedbacks, especially those leading to distributional time lags. Extracting the most relevant factors for TFL changes, especially with regard to climate versus land-use changes, requires more research. Conclusions Existing data on TFL dynamics provide a broad overview of past and current changes, but estimations of reliable TFL changes for Norway as a whole is impossible. The main challenges in future empirically-based predictions of TFLs are to understand causes of time lags, separate effects of contemporary processes, and make progress on the impacts of feedback and interactions. Remapping needs to be continued, but combined with both the establishment of representative TFL monitoring sites and field experiments.
Sammendrag
Det er ikke registrert sammendrag
Sammendrag
During recent decades, forests have expanded into new areas throughout the whole of Norway. The processes explained as causing the forest expansion have focused mainly on climate or land use changes. To enable a spatially explicit separation of the effects following these two main drivers behind forest expansion, the authors set out to model the potential for natural forest regeneration following land use abandonment, given the present climatic conditions. The present forest distribution, a number of high-resolution land cover maps, and GIS methods were used to model the potential for natural forest regeneration. Furthermore, the results were tested with independent local models, explanatory variables and predictive modelling. The modelling results show that land use abandonment, in a long-term perspective, has the climatic and edaphic potential to cause natural forest regeneration of 48,800 km2, or 15.9% of mainland Norway. The future natural forest regeneration following land use change or abandonment can now be spatially separated from the effects of climate changes. The different independent model tests support the main findings, but small fractions of the modelled potential natural forest regeneration will probably be caused by other processes than land use abandonment.
Forfattere
Gaute Velle Anders Bryn Kyrre Kausrud Lawrence R. Kirkendall Martin Malmstrøm Brett Kevin Sandercock Paul Ragnar Berg Kjetil Hindar Johanna Järnegren Erlend Birkeland Nilsen Eva Bonsak Thorstad Anders NielsenSammendrag
This report examines how co-occurring non-native species can interact to create cumulative impacts on ecosystems. Non-native species may interact in additive, antagonistic, or synergistic ways. Through literature review, we found theoretical foundations and empirical examples showing that such interactions often occur. Synergistic interactions are of particular concern. Certain ecosystems appear particularly susceptible, including agricultural landscapes, urban environments, riparian systems, shipping-influenced marine areas, and islands with naïve fauna. We conclude that cumulative effects are ecologically important, and that it would be beneficial to incorporate multispecies interactions into risk assessments of non-native species in Norway.
Sammendrag
Beitebruk er viktig for ressursutnyttelse, selvforsyning, dyrevelferd og kulturlandskap, og det er et politisk mål å øke beiting. Klimaeffektene av beiting har imidlertid vært lite vektlagt. Rapporten sammenstiller kunnskap om hvordan beitedyr påvirker klima gjennom både klimagassutslipp og endringer i vegetasjon og areal. Effektene varierer betydelig mellom arealtyper, beitetrykk, dyreslag og lokale forhold, noe som gjør det vanskelig å trekke generelle konklusjoner. I klimagassregnskapet er beiting særlig relevant for arealbruksendringer, som avskoging til beite og utslipp fra tidligere drenert myr. Effekter på enterisk metan og utslipp fra husdyrgjødsel er relativt små, selv om enkelte norske studier antyder noe lavere metanutslipp ved godt beite på fulldyrka jord. Biogeofysiske effekter som albedo er lite kartlagt, men kan ha nedkjølende effekt i noen områder. Rapporten peker på to hovedutfordringer: behov for sterkere insentiver til å bruke eksisterende innmarksbeiter fremfor nyrydding, og potensial for mer beiting av melkekyr på fulldyrka jord. Det trengs mer forskning for å bedre beregne effekter av beiting i klimagassregnskapet, særlig knyttet til enterisk metan, jordkarbon og beitetrykk i utmark.
Forfattere
Anders BrynSammendrag
Foredrag om spesifikke utfordringer ved overgangen til ny instruks for kartlegging av naturtyper