RØDREVEN I HØYFJELLSØKOSYSTEMET SUBSIDIER? Nina E. Eide NINA HVA LEVER RØDREVEN AV I HØYFJELLET? Siw Killengreen UiT.

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1 RØDREVEN I HØYFJELLSØKOSYSTEMET SUBSIDIER? WORKSHOP RØDREV 211 Nina E. Eide NINA HVA LEVER RØDREVEN AV I HØYFJELLET? Siw Killengreen UiT Foto: Arild Landa 1

2 FRAGMENTERING i NORGE Villmarksområder, mer enn 5 km fra vei/skogsbilvei i Norge (Brun, NOU 1996) UTBYGGING I HØYFJELLET HVA SÅ? Foto:Tommy Sandal 2

3 Kart over sporløype fra en enkelt rev i og ved Hamarseterhøgda hyttefelt den 16 mars. Reven ble sporet på bakspor til disse ikke lenger var synlige på grunn av snøføyke i løpet av natta, og deretter på framspor til den ble støkket ut av dagleie. Samlet lengde på sporløypa er ca. 3,5 kilometer. (Røhnebæk 24) 3

4 Foto:Tommy Sandal Den altitude A B Kilo ometres of trails FJELLREVHI SOM ER I BRUK - Ligger høyere over havet - Ligger lengre fra veier - Ligger lengre fra stier - Ligger lenger fra hytter 6 Beregnet pr 15x 15 km store ruter, analyse fra Børgefjell 3 25 C D 6 etres of roads Kilome Numb ber of cabins Johnsen, Eide & Selås submitted 5 Used Not used Used Not used 4

5 KRAFTLEDNINGER I NORSKE LANDSKAP HVA SÅ? 5

6 ØKT DØDELIGHET FOR FUGL Foto:Tommy Sandal ØKT DØDELIGHET FOR FUGL Totalt taksert antall fugler under kraftledninger : 11 km strekning Bevanger og Brøseth 24 6

7 KRAFTLEDNINGER I NORSKE LANDSKAP Bevanger 1995 Foto: Skuggsjå 7

8 Foto: Jan Ove Gjers ENDRINGER I MATTILGANG? ØKTE HJORTEVILT- BESTANDER Slakteavfall Naturlig dødelighet Trafikkulykker 8

9 Incre ease in fox bounties paid r =.79 SF VA RO TE HO BUAA Increase in number of reindeer felled MR OP Increase in fox bounties paid r =.72 BU NT ST TE VFOP AK HE ØF Increase in number of moose felled (Selås & Vik 26, Selås og Vik 27) Foto: Per Jordhøy 9

10 Reintallsøkningen i Finnmark Tveraa et al, NINA 33 Ittunjarga Olderfjord 32 Silvvetnjarga Reinfjord 28 Cuokcavuotna 27 Joahkonjarga Alta Hammerfest 16b 16c Ravdol-siida Lakselv Njeaiddan-siida Stiipan avzzi Nattvann Geasjav ri Dorskavarri Cuoppo jeaggi Karasjok Kautokeino Kemi/Oskal/Utsi-siida Buol'zajav'ri Gaup-siida Bosmmiidjavrrit N 5.6 log e (N N) ± SE R 2 =.99 (F = 288.9, p <.1, df = 2,3) Time (year) 1

11 Reduksjon i vårvekt, stabil høstvekt Tveraa et al, NINA 7 7 ng BM ± SE Sprin R aut umn =.24 (F = 1.27, p =.33, df = 1,4) 2 R spring =.9 (F = 34.22, p <.1, df = 1,4) 65 6 Autum mn BM ± SE Time (year) % vintertap i Trøndelag, Tverrå et al, NINA 42 Gaupe 4 ekt (kg) Kalveve Ørn Jerv Tap kalv drept kalv i live November Januar Mars Mai 11

12 What subsidize red fox in different phases of the small rodent density cycle? Siw Killengreen, UiT The rise of the mesopredator is often explained by eradication of apex predators But external or management induced resource subsidies could also be influential What subsidize red fox in different phases of the small rodent density cycle? (Paper IV) What is the relative importance of carcasses of ungulates and resources from the marine ecosystem as food for red fox in an area with ice-free coast in the winter? What is the seasonal dynamics of red fox subsidy exploitation Do the spatial extent of marine spillover into the red fox populations vary in various seasons and in different phases of the small rodent density cycle? 12

13 What subsidize red fox in different phases of the small rodent density cycle? Fieldwork conducted during three years (25-27) Small mammal trapping Red fox sampling Complementary methods of diet analysis 1. Diet analysis based on stomach contents 2. Stable isotope analysis Predictor variables: Distance from coast Season Year Catches per 1 trap nights What subsidize red fox in different phases of the small rodent density cycle? (Paper IV) Stomach analysis vole lemming Spring Autumn Spring Autumn Spring Autumn Spring Red foxes used in the study were sampled in the winter months mean wet weight (g) A (km) (km) (km) (km) (km) lemming reindeer marine bird vole ptarmigan 25 (N=27) 26 (N=36) 27 (N=3) 13

14 What subsidize red fox in different phases of the small rodent density cycle? (Paper IV) Isotope analyses Marine prey Composition of carbon (δ 13 C) and nitrogen (δ 15 N) isotopes give a measurement of assimilated diet Isotope measurement in different tissue gives diet in different seasons Terrestrial prey Liver (1 week=winter) Muscle (2-3 months = middle/late winter) Winter fur (late summer/autumn): 14

15 What subsidize red fox in different phases of the small rodent density cycle? Liver (1 week=winter) Muscle (2-3 months = middle/late winter) Fur (late summer/autumn): What subsidize red fox in different phases of the small rodent density cycle? (Paper IV) Our results showed that reindeer carrion was the most important winter resource for red foxes in years with low lemming abundance, especially in inland tundra Voles (i.e. grey side vole and tundra vole) were never an important prey for red fox in winter even though the apparent availability of voles was much larger as that of lemmings There was little spatial extent of the spillover from the marine ecosystem to the inland tundra The marine resource was less important in late summer/ early autumn than during winter 15

16 What subsidize red fox in different phases of the small rodent density cycle? (Paper IV) We suggest that changes in reindeer management may have facilitated the establishment of red fox in the tundra biome RØDREVENS RELASJONER TIL JERVEN - PREDASJON? (intervju) - MEN SPISER DEN RØDREVN? (diett) UNNVIKELSE? (rødrev- (ø fjellrev Sverige) - ARTSSTRUKTUR I HØYFJELLET (kamerastudier) Foto: Arild Landa, NINA 16

17 Dovrefjell 26 (Landa, Sandal & Eide 26) Dovrefjell 26 (Landa, Sandal & Eide 26) 17