ECOLOGICAL SUBSECTIONS OF GATES OF THE ARCTIC NATIONAL PARK & PRESERVE Mapping and Delineation by: Keith Boggs; Julie Michaelson, AK Natural Heritage Program Photographs by: Keith Boggs Alaska Region Inventory and Monitoring Program 2525 Gambell Anchorage, Alaska 99503 Alaska Region Inventory & Monitoring Program 2525 Gambell Street, Anchorage, Alaska 99503 (907) 257-2488 Fax (907) 264-5428 ECOLOGICAL SUBSECTIONS OF GATES OF THE ARCTIC NATIONAL PARK AND PRESERVE Prepared for: National Park Service-Alaska Support Office 2525 Gambell Street Anchorage, AK 99503-2892 By: Keith Boggs And Julie Michaelson Alaska Natural Heritage Program Environment and Natural Resources Institute University of Alaska Anchorage 707 A Street Anchorage AK 99501 December 2001 TABLE OF CONTENTS TABLE OF CONTENTS...............................................................................................ii INTRODUCTION...................................................................................................... 1 Figure 1. Location and administrative boundaries of GAAR. ........................................................... 2 Figure 2. Idealized cross-section of GAAR’s subsections, topography, and landcover...................... 3 Table 1. The National Hierarchical Framework of Ecological Units (after Cleland et al. 1997). .......... 4 Figure 4. Photograph of the arctic foothills north of GAAR............................................................. 4 Figure 3. Landcover map for GAAR (Helt et al. 2000).................................................................... 6 Figure 5. Valley in the north half of the Brooks Range................................................................... 7 Figure 6. Valley in the south half of the Brooks Range. ................................................................. 7 Figure 7. Photograph of the broad valleys south of the Brooks Range. ........................................... 8 Figure 8. General geology map for GAAR (Beikman 1980)........................................................... 10 Figure 9. Surficial geology for GAAR (Hamilton 1999).................................................................. 11 Figure 10. Photograph of solifluction in GAAR............................................................................. 12 Figure 11. Lichen covered alluvial fan in GAAR. .......................................................................... 12 Figure 12. Rock glacier in GAAR................................................................................................. 13 Figure 13. Idealized cross section of a floodplain within the Arctic regions of GAAR. ..................... 14 Figure 14. LandSat image of thermokarst lakes—and kettle lakes—in GAAR. ................................ 15 Figure 15. Sorted polygons north of the Brooks Range................................................................ 16 METHODS............................................................................................................. 17 SUBSECTIONS ...................................................................................................... 20 Table 2. Classification and area (acres) of sections, subsections, and detailed-subsections within GAAR........................................................................................................................................ 20 ARCTIC BROOKS RANGE SECTION................................................................................................. 22 Figure 17. Idealized cross section of a mountain valley in the north half of GAAR showing various surficial geology deposits and landcover types............................................................................. 23 Chandler Mountain Valley Subsection .............................................................................................23 Etivluk Mountain Valley Subsection................................................................................................. 25 Itkillik Mountain Valley Subsection.................................................................................................. 25 Kavachurak Foothills Subsection .................................................................................................... 26 Kavachurak Glaciated Uplands Subsection ...................................................................................... 26 Kavachurak Mountains Subsection.................................................................................................. 27 Killik Mountain Valley Subsection.................................................................................................... 27 Nigu Mountain Valley Subsection.................................................................................................... 28 Noatak Mountain Valley Subsection ................................................................................................ 29 Nukatpiat Hills Subsection ............................................................................................................. 29 Nukatpiat Mountains Subsection .................................................................................................... 30 Oyukak Carbonate Mountains Subsection ....................................................................................... 30 Thibodeaux Noncarbonate Mountains Subsection............................................................................ 31 Utikok Carbonate Mountains Subsection ......................................................................................... 32 SUBARCTIC BROOKS RANGE SECTION................................................................... 34 Alatna Mountain Valley Subsection ................................................................................................. 34 Arrigetch Peaks Granitics Subsection .............................................................................................. 36 Huntfork Noncarbonates Mountain Subsection ................................................................................ 37 Kobuk Mountain Valley Subsection ................................................................................................. 39 Koyukuk Mountain Valley Subsection..............................................................................................40 Mt. Doonerak Mountain Subsection ................................................................................................41 Skajit Carbonate Mountain Subsection............................................................................................42 ARCTIC FOOTHILLS SECTION................................................................................ 45 Anaktuvuk Foothills Subsection ...................................................................................................... 45 Anaktuvuk Glaciated Lowlands Subsection ...................................................................................... 45 Anaktuvuk Lowlands Subsection..................................................................................................... 46 ii Chandler Foothills Subsection ........................................................................................................ 46 Chandler Glaciated Lowlands Subsection ........................................................................................ 47 Chandler Lowlands Subsection....................................................................................................... 48 Etivluk Lowlands Subsection .......................................................................................................... 49 Itkillik Glaciated Lowlands.............................................................................................................. 50 Killik Foothills Subsection............................................................................................................... 51 Killik Glaciated Lowlands................................................................................................................ 51 Killik Lowlands Subsection ............................................................................................................. 52 Klikhtentotzna Creek Lowland Subsection ....................................................................................... 53 Kobuk Lowlands-Tundra Subsection ............................................................................................... 53 Kobuk River Floodplain Subsection ................................................................................................. 54 Koyukuk Lowlands Subsection ....................................................................................................... 55 Koyukuk River Floodplain Subsection.............................................................................................. 56 Figure 19. Idealized cross section of a floodplain within the forested regions of GAAR. ................. 57 Norutak Lake Lowlands Subsection ................................................................................................57 INTERIOR HIGHLANDS SECTION ........................................................................... 58 Angayucham Mountains Subsection................................................................................................ 58 Jack White Range Subsection ........................................................................................................ 59 Lockwood Hills Subsection ............................................................................................................