Spot-satelitten og vegetasjonskartlegging

Stoffet er delvis hentet fra et ikke-ferdig manuskript til min hovedoppgave som vil bli ferdig i løpet av januar 1985, og fra et opphold ved C.N.E.S. Toulouse, Frankrike høsten 1983

Arealplanlegging i reindriften ved hjelp av satellittdata og geografiske informasjonssystemer

Dette er et prosjekt som Norske Reindriftsamers landsforbund har satt i gang. Prosjektets hovedformål er gjennom anvendt- og grunnforskningsinnsats å prøve og utarbeide metoder for anvendelse av satellittdata (fjernmåling) i ressursforvaltningen og arealplanleggingen i reindriften. Dette gjelder arealressurs/vegetasjonskartlegging, estimering og overvåking av vinterbeiteområder for rein og bruk av Geografisk Informasjonssystem for produksjon og oppdatering av temakart som kan brukes overfor forvaltningen

Focus on recent, present and future Arctic and boreal productivity and biomass changes

The reduction of cold temperature constraints on photosynthesis in recent decades has led to extended growing seasons and increased plant productivity (greening) in significant parts of Polar, Arctic and Boreal regions, here called northern lands. However, most territories within these regions display stable productivity in recent years. Smaller portions of Arctic and Boreal regions show reduced productivity (browning). Summer drought and wildfires are the best documented drivers causing browning of continental areas. Yet factors like winter warming events dampening the greening effect of more maritime regions have remained elusive, least monitored and least understood. ANorway-US network project called ArcticBiomass was launched in 2013 to further reveal both positive and negative effects of climate change on biomass in Arctic and Boreal regions. This focus collection named Focus on Recent, Present and Future Arctic and Boreal Productivity and Biomass Changes includes 24 articles and is an important outcome of this work and addresses recent changes in phenology, biomass and productivity and the mechanisms. These mechanisms include former human interactions (legacies) and drivers that control such changes (both greening and browning), along with consequences for local, regional and global scale processes.Wecomplete our synthesis by stressing remaining challenges and knowledge gaps, and provide an outlook on future needs and research questions in the study of climate and human driven interactions in terrestrial Arctic and Boreal ecosystems.publishedVersio

Estimating lichen volume and reindeer winter pasture quality from Landsat imagery

Reindeer and caribou are keystone species in the circumpolar region, and rely on lichens as their main winter forage to survive in some of the most extreme environments on Earth. Lichen mats, however, can be heavily overgrazed at high deer densities, triggering area abandonment or population declines. Although the species' management and conservation require precise information on the quality of winter grazing areas, no reliable and cost-efficient methods are available to date to measure lichen volume across wide and remote areas. We developed a new Lichen Volume Estimator, LVE, using remote sensing and field measurements. We used a Landsat TM land cover mask to separate lichen heath communities from other vegetation types and, therein, we predicted lichen volume from a two dimensional Gaussian regression model using two indexes: the Normalized Difference Lichen Index, NDLI (Band 5−Band 4 / Band 5+Band 4), and the Normalized Difference Moisture Index, NDMI (Band 4−Band 5 / Band 4+Band 5). The model was parameterized using 202 ground measurements equally distributed across a gradient ranging from 0 to 80 lichen dm3/m2 (R2=0.74 between predicted and observed ground measurements), and was validated with a ten-fold cross validation procedure (R2=0.67), which also showed a high parameter stability. The LVE can be a valuable tool to predict the quality of winter pastures for reindeer and caribou and, thus, help to improve the species' management and conservation. Remote sensing Habitat mapping Reindeer Lichen volume and biomass Winter pasturespublishedVersio

Økonomiske tap for reindrifta knyttet til veganlegg på E8 Sørbotn-Laukslett og i Lavangsdalen. Tromsdalen–Mauken reinbeitedistrikt, Tromsø kommune

Rapporten er et oppdrag for Statens Vegvesen, bygd på vedtatte planer og utredninger. Mandatet angir at rapporten skal være et mest mulig objektivt grunnlag for forhandlinger om minnelige løsninger mellom reinbeitedistriktet og Vegvesenet. Utredningsarbeidet er basert på klassisk beitegranskingsmetodikk, men har benyttet foreliggende vegetasjonskart som grunnlag. Det er lagt til grunn en vurdering av beitetapet basert på fullt varig (direkte) beitetap i selve planområdet (2 km2) og redusert (indirekte) beitetap 2 soner 0-1(8,37 km2 ) og 1-2 km (11,66 km2) fra den planlagte veien. Det kalkulerte beitetapet i hver av sonene er kapitalisert ut fra en kalkulasjonsrente på 3%. Det samlede erstatningsbeløpet er beregnet til kr. 2 611 166 kr.Økonomiske tap for reindrifta knyttet til veganlegg på E8 Sørbotn-Laukslett og i Lavangsdalen. Tromsdalen–Mauken reinbeitedistrikt, Tromsø kommunepublishedVersio

Changes in Onset of Vegetation Growth on Svalbard, 2000–2020

The global temperature is increasing, and this is affecting the vegetation phenology in many parts of the world. The most prominent changes occur at northern latitudes such as our study area, which is Svalbard, located between 76°30′N and 80°50′N. A cloud-free time series of MODIS-NDVI data was processed. The dataset was interpolated to daily data during the 2000–2020 period with a 231.65 m pixel resolution. The onset of vegetation growth was mapped with a NDVI threshold method which corresponds well with a recent Sentinel-2 NDVI-based mapping of the onset of vegetation growth, which was in turn validated by a network of in-situ phenological data from time lapse cameras. The results show that the years 2000 and 2008 were extreme in terms of the late onset of vegetation growth. The year 2020 had the earliest onset of vegetation growth on Svalbard during the 21-year study. Each year since 2013 had an earlier or equally early timing in terms of the onset of the growth season compared with the 2000–2020 average. A linear trend of 0.57 days per year resulted in an earlier onset of growth of 12 days on average for the entire archipelago of Svalbard in 2020 compared to 2000.This work (S.R.K.) was supported by the Research Council of Norway under the project Svalbard Integrated Arctic Earth Observing System—Infrastructure Development of the Norwegian Node (SIOS-InfraNor Project No. 269927). This SIOS project (InfraNord instrument #51) is funded by the Norwegian Space Agency (NoSA). The research was also partially funded (S.R.K., H.T.) by the Horizon 2020 project ArcticHubs, grant agreement no 869580. This work (S.B.) was also partially supported by Generalitat Valenciana (SEJIGENT/2021/001), the European Union–Next Generation EU (ZAMBRANO 21-04), and European Research Council (ERC) under the ERC-2017-STG SENTIFLEX project (grant agreement 755617)

Using Ordinary Digital Cameras in Place of Near-Infrared Sensors to Derive Vegetation Indices for Phenology Studies of High Arctic Vegetation

We thank Mark Gillespie, Nanna Baggesen, and Anne Marit Vik for field assistance. The University in Svalbard (UNIS) provided logistical support. This work was funded by the Norwegian Research Council through the ‘SnoEco’ project (project No. 230970) and Arctic Field Grant (No. 246110/E10). It was supported by the ESA Prodex project ‘Sentinel-2 for High North Vegetation Phenology’ (contract No. 4000110654), the EC FP7 collaborative project ‘Sentinels Synergy Framework’ (SenSyF), funding from The Fram Centre Terrestrial Flagship, also from the EEA Norway Grants (WICLAP project, ID 198571), and from the GRENE Arctic Climate Change Research Project, Ministry of Education, Culture, Sports, Science and Technology in Japan.Peer reviewedPublisher PD

Variation in albedo and other vegetation characteristics in non-forested northern ecosystems: the role of lichens and mosses

Vegetation has a profound impact on climate through complex interactions and feedback loops, where especially regulation of albedo, the ratio of reflected to incoming solar radiation, is important at high latitudes. How vegetation albedo varies along environmental gradients in tundra ecosystems is still not well understood, particularly for ecosystems dominated by nonvascular vegetation. We studied broadband shortwave albedo of open boreal, arctic, and alpine ecosystems over a 2000 km long latitudinal gradient (60◦ N–79◦ N) and contrasted this against species composition, vegetation greenness (normalised difference vegetation index—NDVI), momentary ecosystem CO2 fluxes and reindeer (Rangifer tarandus) grazing pressure. High cover of pale terricolous fruticose lichens was the single most important predictor for vegetation albedo, which had a maximum value of 0.389 under clear sky conditions and solar zenith angle 60◦. To our knowledge, this is the highest broadband albedo recorded for a vegetated surface. NDVI was negatively correlated to lichen biomass (rs = −0.56), and albedo (rs = −0.19). Gross primary production and ecosystem respiration varied considerably less between plots and vegetation types than albedo. While it is well-known that Rangifer affects climate-relevant aboveground biomass, we here show that its regulation of surface albedo in northern ecosystems may also be of high importance for land-atmosphere interactions. The data presented here thus advocate for an increased understanding of the important and complex role of herbivores and lichen cover in climate-vegetation interactions.publishedVersio