Anders Bryn

Research Scientist

(+47) 930 39 782
anders.bryn@nibio.no

Place
Ås O43

Visiting address
Oluf Thesens vei 43, 1433 Ås

Biography

I work as a researcher in a 20 % position in the Department of Land Resource Surveys, Division of Survey and Statistics.

My work is primarily related to vegetation mapping, the project Arealregnskap i utmark (AR18X18), mountain farming and contributions to other departments (applications, articles, dissemination, etc.). I also generally contribute to the development, research and dissemination of methodology for mapping of outfield lands.

My subject areas are:
- vegetation mapping
- distribution modelling
- tree- and forest lines
- ecological climatology
- citizen science
- land use

I have a Master degree in vegetation ecology from the University of Oslo and a PhD in biogeography from the University of Bergen.

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Abstract

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.

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Abstract

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.

Abstract

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.

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Abstract

The global climate is warming, especially in northern regions due to high-latitude amplification. This high-latitude warming leads to range expansion with advancing tree- and forest-lines (TFLs) in the Northern Hemisphere. However, empirical studies can rarely provide a well-documented elevational expansion rate, especially for timescales longer than 40–50 years. This study provides a unique long-term dataset on TFL dynamics of Betula pubescens subsp. czerepanovii in Norway, based on a combination of resampled historical data (n = 319) and new field registrations (n = 447). Our dataset includes a total of 766 registrations from five counties in Norway. In total, the dataset contains 439 treelines and 327 forest lines, most likely representing the highest recorded TFLs for the region at the given time. For all data, both resampled and new, locality, coordinates, elevation, aspect and spatial uncertainty and the resampling/sampling methods and definitions are provided. The entire material is stored and available for download through the Global Biodiversity Information Facility (GBIF) portal. This dataset includes newly-resampled TFLs, based on 57–127-year-old registrations. The entries provide elevational changes, georeferenced localities and potential sites for monitoring climate change effects. The entries enable regional analyses of TFL dynamics on intermediate timescales, including the effect of time lags. The material is available for modelling TFL range shifts along the boreal-alpine ecotone. This dataset most likely provides the highest registered Betula pubescens subsp. czerepanovii locations within their specific regions, thus representing the contemporary ecophysiological range limits for the life-form tree. Additional high-elevation TFL sites and localities have been added to make the material suitable for future remapping and monitoring of climatic TFL dynamics.