Habitat use by semi-domesticated reindeer, estimated with pellet-group counts

Habitat selection theory predicts that herbivores should select for or against different factors at different spatial scales. For instance, quantity of forage is expected to be a strong factor influencing habitat choice at large scales, while forage quality may be important at finer scales. However, during summer, herbivores such as reindeer ( Rangifer tarandus tarandus ) can be limited in their grazing time by insect harassment, and do not always have the possibility to select for high quality forage. Human disturbances from hikers, etc., can also have a limiting effect on the possibility for reindeer to graze in high quality foraging habitats. Reindeer habitat selection at the landscape level was investigated through faecal pellet-group counts during the summers of 2002 and 2003 in two reindeer herding districts in Sweden. Resource utilization functions (RUFs) were developed using multiple linear regressions, where the pellet densities were related to vegetation types, topographic features, distances to tourist resorts, and distances to hiking trails. Validations of the models were performed through cross-validation correlations. Results show that high altitudes with high quality forage were important habitats. Areas that offer both snow patches and fresh forage plants for the reindeer were used in relation to their availability. The reindeer also seemed able to habituate to human intervention to a certain extent. The predictive capabilities of the RUF models were high and pellet-group counts seemed well suited to study how abiotic factors affect the habitat use at large temporal and spatial scales Abstract in Swedish / Sammanfattning: Renens anvandning av sommarbetesomradet, uppskattat med spillningsinventeringar Hierarkiskt habitatval innebar att djur valjer for och emot olika faktorer beroende pa den rumsliga skalan. Mangden bete kan t ex spela stor roll for en vaxtatares habitatval pa en stor skala medan kvaliten pa betet kan ha storre betydelse pa en mindre skala. For renar ( Rangifer tarandus tarandus ), kan betestiden och mojligheten att hitta bra bete sommartid begransas bade pa stor och liten skala pga. storningar fran insekter och mansklig aktivitet. Har studerades renarnas val av betesomrade pa landskapsniva med hjalp av spillningsinventering under somrarna 2002 och 2003 i tva samebyar i Sverige. Spillningstatheten for respektive omrade och ar undersoktes statistiskt med hjalp av multipel linjar regression eller sk ”resource utilisation functions” (RUF). Dar relaterades spillningstatheten till vegetationstyp, olika topografiska faktorer, avstand till vandringsleder, stugplatser och fjallstationer. Resultaten visade att omraden hogt upp i terrangen med hog beteskvalitet var attraktiva. Vegetationstypen moderat snolega som anses ha hog beteskvalitet anvandes av renarna i relation till dess forekomst. Daremot verkade renarna undvika omraden kring valbesokta fjallstugor och fjallstationer medan de daremot t o m foredrog omraden nara vandringsleder. Det kan bero pa att vandringslederna gar genom attraktiva vegetationstyper. RUF-modellerna hade en hog prediktiv formaga vilket visar att spillningsinventeringar ar anvandbara nar man onskar studera hur djuren anvander ett betesomrade i relation till olika faktorer pa en relativt stor rumslig och temporal skala.