Hvordan elgens aktiviteter rundt fôringsplasser påvirker vegetasjon, småfugler og mus

Vi har studert hvordan elgbeiting og fôringsplasser for elg påvirker vegetasjon, småfugler og mus i Stor-Elvdal i perioden 2004-2011. Det viser seg at fôringsplasser påvirker elgens fordeling i landskapet om vinteren og elgens beiting påvirker vegetasjonen, noe som igjen påvirker tilgang av mat og strukturen på leveområdet for andre dyr i skogen. Høy elgbeiting kan for eksempel føre til mindre tilgang på insektlarver for kjøttmeisunger. I tillegg fører fôringsplasser til lokale effekter gjennom gjødsling og endring av vegetasjonen på bakken. I denne artikkelen oppsummerer vi noen av resultatene med vekt på eksempler fra Stor-Elvdal

Cascading effects of moose (Alces alces) management on birds

This is the preprint version of the articleLarge herbivores often have key functions in their ecosystems, and may change ecosystem processes with cascading effects on other animals. The mechanisms often involve relocations of resources of various kinds, including reduction in resource availability following large herbivore foraging and increase in resources from animal excreta. As large herbivore populations in Europe generally are intensely managed, management activities may interact with the activities of the herbivores themselves in the effect on other ecosystem components. We investigated the effects of moose (Alces alces) winter browsing, together with the effect of net nutrient input via supplementary winter feeding of moose on functional composition and species richness of birds in a boreal forest. Supplementary feeding stations for moose had a net zero effect on bird species richness and abundance, because negative effects of moose browsing were balanced by positive effects of nutrient input. Sites with a similar browsing intensity as at feeding stations but without nutrient input had lower abundance and species richness than feeding stations. Functional groups of bird species showed differing responses: Birds nesting at or below browsing height were negatively affected by moose browsing, whereas species nesting above the browsing zone were positively affected by moose browsing. Insect eating species responded negatively to moose browsing on birch but positively to nutrient input at feeding stations, whereas seed eating species responded positively to birch browsing and negatively to feeding stations. This study showed that both high levels of cervid activity and human management interventions influenced the bird community

En integrerad förvaltning av älg och skog

I detta kapitel diskuterar vi möjligheten att i ökad omfattning utnyttja både värdet av skog och av älg genom en aktiv integrerad förvaltning av båda resurserna. En sådan samförvaltning bygger på att hålla ett riktigt förhållande mellan älgtäthet och foderresurser, till exempel genom att aktivt öka foderproduktionen medan älgtätheten bestäms av det tillgängliga fodret och det krav man har på täthet av oskadade stammar i unga furubestånd. I en experimentell studie prövar vi olika enkla åtgärder i skogsbruket för att öka produktionen av älgfoder som är smakligare för älgen än de träd som avses bilda det slutliga beståndet. Åtgärderna bygger på tidigare grundläggande studier av älgens matval i relation till bland annat beståndstäthet och tidigare bete på det enskilda trädet

The importance of evaluating standard monitoring methods: Observer bias and detection probabilities for moose pellet group surveys

Counting is not always a simple exercise. Specimens can be misidentified or not detected when they are present, giving rise to unidentified sources of error. Deer pellet group counts are a common method to monitor abundance, density, and population trend. Yet, detection errors and observer bias could introduce error into sometimes very large (spatially, temporally) datasets. For example, in Scandinavia, moose (Alces alces) pellet group counts are conducted by volunteer hunters and students, but it is unknown how much uncertainty observer error introduces into these datasets. Our objectives were to 1) estimate the detection probability of moose pellet groups; 2) identify the primary variables leading to detection errors including prior observer experience; and 3) compare density estimates using single and double observer counts. We selected a subset of single observer plots from a long-term monitoring project to be conducted as dependent double observer surveys, where primary and secondary observers worked simultaneously in the field. We did this to quantify detection errors for moose pellet groups, which were previously unknown in Scandinavia, and to identify covariates which introduced variation into our estimates. Our study area was in the boreal forests of southern Norway where we had a nested grid of 100-m2 plots that we surveyed each spring. Our observers were primarily inexperienced. We found that when pellet groups were detected by the primary observer, the secondary observer saw additional pellet groups 42% of the time. We found search time was the primary covariate influencing detection. We also found density estimates from double observer counts were 1.4 times higher than single observer counts, for the same plots. This density underestimation from single observer surveys could have consequences to managers, who sometimes use pellet counts to set harvest quotas. We recommend specific steps to improve future moose pellet counts.The importance of evaluating standard monitoring methods: Observer bias and detection probabilities for moose pellet group surveyspublishedVersio

Is heavy browsing a threat to biodiversity in a boreal ecosystem?

Posteren ble presentert på Sustainable Conservation: Bridging the gap between disciplines i Trondheim 15.-18. mars 2010Herbivore numbers have been increasing across Europe and North America in recent decades, with implications for whole ecosystems including impacts on biodiversity. Moose populations in Scandinavia are no exception, leading to intense browsing of commercially important boreal forests. We examined the impact of moose browsing on species richness and abundance of 4 functional groups of plants (grasses, forbs, dwarf shrubs and canopy trees) and 2 functional groups of passerine birds (seed-eaters and insect-eaters) along a browsing gradient from sites of heavy browsing around supplementary feeding stations to light browsing at control sites. Both positive and negative effects were recorded

Ecological Effects of Wolves in Anthropogenic Landscapes: The Potential for Trophic Cascades Is Context-Dependent

In recent years, large predators have made a comeback across large parts of Europe. However, little is known about the impact that recolonizing predators may have on ecosystems with high degrees of anthropogenic influence. In Scandinavia, wolves (Canis lupus) now inhabit areas affected by intense forestry practices and their main prey, moose (Alces alces), are exposed to significant human hunting pressure. We used long-term datasets to investigate whether the return of wolves has affected moose distribution (i.e., presence and abundance) as well as browsing damage (i.e., presence and intensity) by moose on Scots pine (Pinus sylvestris). We found that the probability of moose presence and abundance increased with time since wolf territory establishment and was higher inside wolf territories than outside. Additionally, the probability of browsing damage was also higher inside wolf territories compared to outside, but wolf occurrence had no effect on browsing damage intensity. We suggest two possible underlying mechanisms behind these results: (1) wolves might select to establish territories in areas with higher moose abundance, increasing their probability of encounters, and/or (2) hunters within wolf territories reduce the number of harvested moose to compensate for wolf predation. This study highlights that the return of large predators to landscapes with strong anthropogenic influence may result in alternative effects than those described in studies on trophic cascades located in protected areas

SHOOT GROWTH RESPONSES AT SUPPLEMENTARY FEEDING STATIONS FOR MOOSE IN NORWAY

Moose browsing pressure in the vicinity of supplementary winter feeding stations eventually declines over time. It is believed that continual winter browsing over multiple years causes locally reduced shoot growth and forage availability for moose (Alces alces). We tested this hypothesis by comparing the size of annual shoots of Scots pine (Pinus sylvestris), downy birch (Betula pubescens), and Norway spruce (Picea abies) along a distance gradient from supplementary feeding stations. Contrary to our hypothesis, we found that shoot size was larger at feeding stations than at distances out to 1500 m. This increase in shoot size was probably not related directly to browsing, but to higher nutrient and light availability associated with moose activity at feeding stations. Increased use of Norway spruce, yet reduced browsing overall at feeding stations, probably reflects the overall decline in abundance of preferred Scots pine and downy birch in a local environment substantially altered by an artificially and abnormally high density of moose

Effects of Increased Soil Scarification Intensity on Natural Regeneration of Scots Pine Pinus sylvestris L. and Birch Betula spp. L.

publishedVersio

Shoot growth responses at supplementary feeding stations for moose in Norway

Moose browsing pressure in the vicinity of supplementary winter feeding stations eventually declines over time. It is believed that continual winter browsing over multiple years causes locally reduced shoot growth and forage availability for moose ( Alces alces ). We tested this hypothesis by comparing the size of annual shoots of Scots pine ( Pinus sylvestris ), downy birch ( Betula pubes- cens ), and Norway spruce ( Picea abies ) along a distance gradient from supplementary feeding stations. Contrary to our hypothesis, we found that shoot size was larger at feeding stations than at distances out to 1500 m. This increase in shoot size was probably not related directly to browsing, but to higher nutrient and light availability associated with moose activity at feeding stations. Increased use of Norway spruce, yet reduced browsing overall at feeding stations, probably reflects the overall decline in abundance of preferred Scots pine and downy birch in a local environment substantially altered by an artificially and abnormally high density of moos

Elg som næring : elgarbeid på Evenstad 1995 – 2013

I 1995 byrja me å studera elg og trafikk i Østerdalen. Då ulv etablerte seg i studieområdet, undersøkte me verknaden av ulv på elg. Sidan studerte me elgøkonomi før me såg på verknaden av elgfôring i samarbeid med Stor-Elvdal Grunneierforening, Løvenskiold-Fossum og Fritzøe Skoger. No arbeider me med samordna forvalting av skog og elg, der me prøver ut ordinære skogbrukstiltak som skal gje elgen meir fôr og skogeigaren uskadde furuforyngingar. I alt har me radiomerka 268 elgar, og me har studert elg og vegetasjon i felt. Me gjev her ei grov oversikt over resultata frå det vitskaplege arbeidet med elg på Evenstad, gjev forvaltningsråd basert på dette og viser kva me vil arbeida med framover. Hovudfokus i heile perioden har vore å sjå på elgen som ein ressurs. Arbeidstittelen har vore Elg som næring. Elg er mykje meir enn næring, men i denne artikkelen ser me på elgen hovudsakleg i næringsmessig samanheng sett med lokaløkonomiske auger