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 23)
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
The Norwegian area frame survey of land cover and outfield land resources (AR18X18), completed in 2014, provided unbiased statistics of land cover in Norway. The article reports the new statistics, discusses implications of the data set, and provides potential value in terms of research, management, and monitoring. A gridded sampling design for 1081 primary statistical units of 0.9 km2 at 18 km intervals was implemented in the survey. The plots were mapped in situ, aided by aerial photos, and all areas were coded following a vegetation type system. The results provide new insights into the cover and distribution of vegetation and land cover types. The statistic for mire and wetlands, which previously covered 5.8%, has since been corrected to 8.9%. The survey results can be used for environmental and agricultural management, and the data can be stratified for regional analyses. The survey data can also serve as training data for remote sensing and distribution modelling. Finally, the survey data can be used to calibrate vegetation perturbations in climate change research that focuses on atmospheric–vegetation feedback. The survey documented novel land cover statistics and revealed that the national cover of wetlands had previously been underestimated.
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
Paul Ragnar Berg Lawrence Richard Kirkendall Kyrre Linné Kausrud Martin Malmstrøm Anders Bryn Kjetil Hindar Johanna Järnegren Anders Nielsen Erlend Birkeland Nilsen Brett Kevin Sandercock Eva Bonsak Thorstad Gaute VelleSammendrag
Import of leeches for medical use and hobby keeping poses a low risk of negative effects on Norwegian biodiversity. This is the key message in a risk assessment of two species of blood-sucking leeches conducted by VKM for the Norwegian Environment Agency. Background The two species of leeches (Hirudo medicinalis and H. verbana) have in recent years become more commonly used in Western medicine for various procedures where maintaining good blood flow is important. Hirudo medicinalis is considered native to Norway and is found in scattered populations in southern Norway. There is uncertainty about the genetic impact on these populations if imported leeches were to be released into the wild. Hirudo verbana is not registered in Norway but may have been imported as H. medicinalis in the past. Both species are listed under Appendix I, List B of the Norwegian CITES regulations. Methods VKM reviewed scientific literature to uncover potential negative effects in light of the leeches’ ecology under Norwegian conditions. VKM also investigated how the trade in live leeches is conducted, where they originate from, and outlined possible risk-reducing measures. VKM assessed four factors of potential relevance for negative impacts on biodiversity and conducted risk assessments for each: Hybridisation or other negative genetic impacts on local populations Competition with other leech species Parasitism or predation on amphibian populations Transmission of diseases Additionally, VKM assessed the extent of such imports and the likelihood of imported leeches ending up in Norwegian nature. Results VKM concluded that it is moderately likely that H. medicinalis will genetically affect Norwegian populations, but this will have minimal negative effects. Hybridisation between H. verbana and H. medicinalis is considered unlikely and would have little effect if it occurs. ”The leeches already present in Norway mainly originate from leeches imported from Europe in the 1800s. The introduction of new genes from the same areas now will therefore have minimal impact. The risk is therefore low,” says Lawrence Kirkendall, the scientific leader of the work. For parasitism or predation, amphibians are the main species that could theoretically be negatively affected by the leeches. VKM concludes that such negative effects are very unlikely and would have little or minimal impact. This implies low risk. Regarding competition and disease transmission, VKM assesses that these factors have little or minimal effect on biodiversity and are very unlikely. "We assess that the effects on biodiversity in Norway, if imported leeches were to end up in an environment where they thrive, are very small. At the same time, it is very unlikely that leeches used for medical procedures will end up in nature. The overall assessment is therefore that both species are associated with low risk of negative impact on biodiversity," says Kirkendall. The risk assessment is approved by the VKM Panel for Biodiversity.
Forfattere
Martin Malmstrøm Gaute Velle Johanna Järngren Paul Ragnar Berg Brett Kevin Sandercock Anders Bryn Kjetil Hindar Lawrence R. Kirkendall Kyrre Linné Kausrud Erlend Birkeland Nilsen Eva Bonsak Thorstad Anders NielsenSammendrag
Import av fremmede krabber til bruk i mat- og restaurantbransjen kan medføre en høy risiko for negative effekter på norsk biologisk mangfold. Det er hovedbudskapet i en risikovurdering av åtte arter krabber, som VKM har gjort for Miljødirektoratet. Tre av disse artene er tidligere blitt beslaglagt av Tollvesenet, og disse var med høy sannsynlighet ment for mat-, og restaurantbransjen. Krabbene var levende da de ble forsøkt innført til Norge fra Sverige. På bakgrunn av beslagene besluttet Miljødirektoratet å få gjennomført en vurdering av hvilken risiko slik import kan medføre for biologisk mangfold i Norge. Ytterligere fem arter, identifisert av Havforskningsinstituttet som aktuelle for import som mat, inngikk i VKMs oppdrag. Dette har VKM gjort: VKM har gått gjennom tilgjengelig vitenskapelig litteratur om de aktuelle artene, og vurdert hvilke negative effekter disse kan føre til dersom de kommer ut i norsk natur. VKM har også gjort en vurdering av hvor sannsynlig det er at artene vil kunne etablere seg i Norge. Risikoen som krabbene utgjør bestemmes dermed av effekter og sannsynlighet. I tillegg har VKM foreslått mulige risikoreduserende tiltak. Effekter og sannsynlighet utgjør til sammen risikoen hver art medfører. VKM identifiserte tre faktorer som kan påvirke det biologiske mangfoldet negativt. Vi har gjennomførte risikovurderinger for hver av disse faktorene: konkurranse med hjemmehørende arter predasjon og beiting på hjemmehørende arter overføring av sykdommer I tillegg kan etablering av enkelte av artene, spesielt kinesisk- og japansk ullhåndskrabbe, og deres adferd med å grave ganger i elvebredden, føre til strukturelle endringer i økosystemene. Resultater_ VKMs risikovurderingen indikerer varierende risikonivåer for de ulike faktorene og artene. Vi konkludere med at det er høy risiko for negative effekter som følge av konkurranse og predasjon for to av artene, og middels risiko for ytterligere fem. Når det gjelder sykdomsspredning, er det høy risiko knyttet til de to ullhåndskrabbe-artene, og mulig høy risiko knyttet til amerikansk steinkrabbe. Sykdommene som utgjør den største trusselen, er krepsepest og gaffkemi, som rammer ferskvannslevende edelkreps og hummer hardest. VKM vurderer også at tre av artene utgjør en moderat risiko knyttet til gravende adferd. ‑ Fremmede krabber som importeres levende som mat har et betydelig potensial for å etablere seg i sjø og ferskvann. Sannsynligheten for etablering er høy fordi artene er tilpasningsdyktige, fordi enkelte arter kan tolerere miljøforhold lik det som finnes i store deler av Norge i dag, og fordi artene har høy reproduksjonsrate, sier Gaute Velle som har vært faglig ansvarlig for vurderingen. VKM har også gjort en totalvurdering av hvilken risiko de åtte artene utgjør dersom de importeres levende som mat. ‑ Spesielt sykdommer, som også kan spres av døde eller døende krabber, er en bekymring sier Velle. Potensialet for spredning av sykdommer har derfor veid tung når de åtte artene er rangert. Totalt sett er det lav risiko for kun to av de åtte artene, mens det er høy-, eller muligens høy risiko for tre arter og moderat risiko for tre arter, dersom artene importeres levende til bruk i mat-, og restaurantbransjen. Risikovurderingen er godkjent av VKMs faggruppe for biologisk mangfold.
Forfattere
Anders Bryn Diress Tsegaye Alemu Christian Pedersen Svein Olav Krøgli Kerstin Potthoff Wenche DramstadSammendrag
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