Stipendiatstillinger til NINA (2017-2022)

Mehlhoop: Evaluating mitigation measures to reduce negative impacts of infrastructure construction on vegetation and wildlife The human footprint is large and growing worldwide. Land-use related to technical infrastructure development, such as road construction or power grid systems, leads to degradation of natural habitat and contributes to 23% of anthropogenic GHG emissions globally. Combined, this causes major declines in biodiversity and, in extension, ecosystem function. Nevertheless, human mobility will further increase and so will technical infrastructure development. In both road construction and power grid system projects large areas are influenced by construction work and accordingly, large areas of habitat are fragmentated and lost. An approach to combat biodiversity loss due to infrastructure development, is to apply the principles and ideas of ecological restoration within the planning and implementation of mitigation measures. The aims of this thesis are 1) to give an impression of the negative impacts of large infrastructure projects on biodiversity in Norway, 2) to study the mitigation measures conducted to reduce these negative impacts and 3) to evaluate the effectiveness of the mitigation measures. This was addressed by using forest inventory data to investigate impacts of distance to roads and houses on moose browsing, and a possible cascading effect on tree recruitment. Further, landscape fragmentation and its mitigation for moose and deer, in form of effective use and placement of wildlife crossing structures, was investigated by the use of a novel method (Equivalent Connected Habitat). Lastly, the effectiveness of revegetation measures in large infrastructure constructions was evaluated with vegetation analysis, comparing different revegetation treatments and levels of survey detail. Eriksen: Life history traits and demography of a mountain bird under climatic variation Mountain ecosystems are particularly exposed to increased temperature, shorter winters, reduced snow cover and changed precipitation patterns as a result of climate change. For many species that live in the mountains, we have little knowledge of the importance of climate variation for various characteristics such as the ability to survive or how many offspring an individual has. This makes it difficult to predict how populations will develop in a changing climate. The willow ptarmigan is an iconic and culturally important species in the Norwegian mountains, and with an important role in the mountain ecosystem. Through this doctoral work, it has been looked at how climate variations affect survival, reproductive success and movement in willow ptarmigan, using data from two study areas (Dovrefjell and Lierne). The results show that increased spring temperatures advanced the timing of egg-laying, and early egg-laying led to a higher number of chicks, but the number of eggs laid was independent of body size and age. The study population in Lierne is partly migratory, and through the project it was revealed that the probability of young birds migrating increases with low body weight. Later snowfall in autumn gave higher spring survival for young individuals, and less snow in spring gave higher survival for both young and adults. The results show that willow ptarmigan is sensitive to short-term variation in climate.

Mehlhoop: Effektiviteten av dyrelivskryssingsstrukturer og revegeteringstiltak i samband med stor infrastruktur er vurdert. Den avbøtende effekten av viltoverganger kan være liten dersom landskapet rundt blir degradert. Tid er viktigst for vellykket revegetering, mens valg av revegeteringstiltak er av mindre betydning. Naturlig revegetering vil kunne gi bedre eller like gode resultater med tanke på vegetasjonsutvikling. Denne oppgaven påviser mangel på overvåking av avbøtende tiltak. For å kunne beskytte og gjenopprette det biologiske mangfoldet må vi kjenne til effekten av avbøtende tiltak, og derfor er det nødvendig med en godt planlagt, gjennomtenkt, repeterbar og målrettet overvåking av avbøtende tiltak, helst over en lengre tidsperiode. Det anbefales en BACI (Before-after-control-impact)-tilnærming for større prosjekter, noe som innebærer at det også må samles data før byggestart. Eriksen: Doktorgradsarbeidet har demonstrert at kunnskapen om klimapåvirkninger på fjelløkosystemer er mangelfull og svært viktig å bygge opp. Forvaltningsmessig er det både sentralt og lokalt etterspurt kunnskap om hvilke andre påvirkningsfaktorer utenom jakt som påvirker rypebestander, og med spesielt stort fokus på effekter av klimavariasjoner. Studiene har vist at senere snøfall om høsten ga høyere våroverlevelse for unge individer, og mindre snø om våren ga høyere overlevelse for både unge og voksne. Videre ga både tidligere vår og varmere vår høyere reproduksjonssuksess. Migrasjonsmønstre hos lirype var også påvirket av individuelle forskjeller. Resultatene har gitt ny kunnskap og viktige bidrag for å forstå fremtidig populasjonsutvikling for lirype og dens påvirkning på økosystemet.