Framtidas rypeforvaltning i Statskog

Sustainable harvest of willow ptarmigan (Lagopus lagopus), a popular and red-listed small game species, is a challenging task. It is crucial for managers to identify correct harvest levels, and to gain knowledge on the relationship between hunters' attitudes towards harvest restrictions and the actual effect of restrictions on both the hunters and the ptarmigan populations. There is also a need for an improved understanding of what other influential factors affect ptarmigan population growth. Recently, attention has been aimed at the range expansion and increasing densities of red fox (Vulpes vulpes) and the potentially elevated predation rate on willow ptarmigan. An increase in generalist predator abundance along with dampened small rodent cycles may contribute to further decline in ptarmigan and other alternative prey species Earlier studies of willow ptarmigan have lacked detailed data on hunter effort, bag records and density estimates from large areas over time. Few studies have evaluated the relationship between restrictions imposed on hunters, their attitudes, and the actual impact on the harvest levels. Furthermore, studies on the relationship between small rodents, predators and alternative prey (APH) have limited information about one of the main factors; the predators. In this thesis I will (i) estimate ptarmigan harvest rates in a large spatiotemporal scale, and evaluate determinant factors for harvest rates, hunting effort and hunter efficiency. Next, I will (ii) study hunters? attitudes towards imposed harvest restrictions and evaluate their effect. Lastly, I will (iii) examine to which degree spatiotemporal patterns in willow ptarmigan population growth are affected by an interaction between small rodents and red fox abundance. I estimated harvest rates in 162 hunting blocks on 26,828 km2 of state-owned land in Nordland and Troms Counties in 2013-2016. I found that the mean harvest rate was below 10%, and according to previous studies, hunting mortality at this low level is probably compensatory. The number of hunters, the number of days hunted per area and bag sizes varied markedly between years. Both the catch per unit effort (CPUE) and bag sizes increased with increasing ptarmigan densities, but the slopes of these relationships indicated higher harvest rates at low densities. A model of determinant factors for harvest rates confirmed that hunting impact on ptarmigan was inversely related to density. I evaluated the hunters? (n = 570) opinions towards restrictions and the effect of the restrictions based on bag records (n = 8,795) from state-owned land in Nordland County in the period 2009-2012. I found that access and opportunity to hunt was the most important motivating factor for hunters, and most hunters (89%) were positive to restrictions in harvest if necessary. However, in order to reduce the harvest efficiently, the regulations had to be set lower than the hunters found acceptable. The residency of the hunter was the most influential factor regarding attitudes towards hunting restrictions. The hunters were generally more positive towards hunting restrictions that would have the smallest effect on their own hunting practice. The daily bag limit of 4 birds was reached in <6% of all reported hunting days and had little effect on the total harvest. Finally, I analyzed abundance data on rodents, red fox and ptarmigan from Hedmark County (2006-2014), and found that that the population growth and breeding success of ptarmigan was determined by an interaction between red fox and small rodents. A negative impact of red fox on ptarmigan appeared only when small rodent densities were low. This result is in accordance with the APH hypothesis and confirms the important role of red fox in the willow ptarmigan population dynamics. Based on these results, I recommend managers of ptarmigan to continue population surveys and to record hunting effort and hunting bags in order to be able to implement harvest restrictions when needed. Harvest restrictions should be based on knowledge of population abundance, harvest rates and the actual effect of the restriction.

Viltforvaltning er menneskenes målrettede innsats for å øke, minske, høste eller overvåke viltbestander. God viltforvaltning krever kunnskap om økologi, men også om menneskers mål og følelse av måloppnåelse. Allerede i 1933 påpekte Aldo Leopold at det oft e var langt lettere å påvirke viltet enn menneskene og deres mål. Den planlagte doktorgraden er ikke en tradisjonell oppgave i økologi, men en oppgave i Anvendt økologi der målet er å anvende økologisk kunnskap for å løse konkrete forvaltningsoppgaver. Stipendiaten skal studere virkningen på såvel ryper som jegere og rettighetshavere ved gjennomføring av forskjellige forvaltningsmodeller. I avhandlingen vil det være 4 hovedartikler, men stipendiaten vil også kunne samarbeide med andre i prosjektet og forfatte/medforfatte andre artikler. Artiklene vil bli søkt publisert i internasjonale vitenskaplige tidsskrift for viltforvaltning som The Journal of Wildlife Management, Wildlife Biologi og The European Journal of Wildlife Research. Han skal etter pla nen studere 1) ett tiltak i småviltsamfunnet som har til hensikt å øke rypebestanden, 2) virkningen på rypebestanden av forskjellige forvaltningsmodeller; begrensning av jaktinnsats, begrensning av uttak, 3) virkningene på rypebestanden av å benytte en fo rvaltningsmodell som innebærer at enkeltområder blir fredet mot jakt (refugiemodell) og 4) hvordan jegerne oppfatter og respekterer et nytt system for salg og rapportering av småviltjakt. Han vil dermed studere økologiske prosessers virkning på rypebestan den, jaktens betydning på rypebestanden og hvordan jegere oppfatter innføringen av forvaltningstiltak. Doktorgradsarbeidet vil være å anvende økologi innen viltforvaltning på et for Statskog sentralt område. Men arbeidet skal resultere i 4 (evt. 5) artikl er som skal publiseres i fagfellevurderte internasjonale tidsskrifter.