Increased wetness confounds Landsat-derived NDVI trends in the central Alaska North Slope region,

Transcription

1 Increased wetness confounds Landsat-derived s in the central Alaska North Slope region, Martha K Raynolds and Donald A Walker Institute of Arctic Biology, University of Alaska Fairbanks, P O Box , Fairbanks AK99775, USA mkraynolds@alaska.edu Supplemental Materials Figure S1. Geoecological maps of Map A within the Prudhoe Bay Oilfield (see Fig. 2 in main paper for location). a) simplified NSSI map, showing infrastructure in place in 2008 (30-m pixels, (Ducks Unlimited 2013). Predevelopment b) vegetation types, c) surface form and d) landform as mapped by Walker et al. (1987).

2 Figure S2. Geoecological maps of Map B within the Prudhoe Bay Oilfield (see Fig. 2 in main paper for location). a) simplified NSSI map, showing infrastructure in place in 2008 (30-m pixels, (Ducks Unlimited 2013). Predevelopment b) vegetation types, c) surface form and d) landform as mapped by Walker et al. (1987). Figures S2b) and S2c) were published in "Cumulative geoecological effects of 62 years of infrastructure and climate change in ice-rich permafrost landscapes, Prudhoe Bay Oilfield, Alaska", Raynolds et al., Global Change Biology 20(4): , 2014, Global Change Biology, Wiley.

3 Disturbance Types Figure S3. Significant s for three tasseled-cap indices (units/year, 1985 to 2011, p < 0.05) for disturbance categories within 60 km 2 mapped within the Prudhoe Bay Oilfield. Dr = drilling pads and roads, Er = erosion, Fl = flooding caused by blocked drainage, Gr = gravel deposition, Mi = mining excavations for gravel fill, Pd = permafrost degradation adjacent to facilities, Ro = roadside gravel and dust, Th = thermokarst away from facilities, Tr = vehicle trails, pipelines, fences, powerlines, Ve = revegetation. Flooded areas (Fl) had a large decrease in TC1 -, with little change in TC2 - or TC3 -. Thermokarst areas (Th), where permafrost degradation occurred far from infrastructure, showed little change in TC1 -, but increasing TC2 and TC3 -. The largest increases in TC2 - occurred in areas that had been mined for gravel (Mi), in areas of riparian gravel deposition (Gr), and areas where revegetation of natural and industrial disturbance had occurred (Ve). The largest increases in TC3 - occurred in areas of drilling and production pads and roads (Dr) and in adjacent thermokarst due to permafrost degradation (Pd).

4 Figure S4. Map A within Prudhoe Bay Oilfield, Alaska (see Fig. 2 in main paper for location). a) 2010 aerial photograph; b) significant s in Landsat (); c) mapped changes from 1983 to 2010 from analysis done by Raynolds et al. (2014); d) significant s in TC1- (units/year, , ); e) significant s in TC2- (units/year, , ); f) significant s in TC3- (units/year, , ). The gray background lines are those of the Integrated Geoecological and Historical Change Map (Raynolds et al. 2014).

5 Figure S5. Map C within Prudhoe Bay Oilfield, Alaska (see Fig. 2 in main paper for location). a) 2010 aerial photograph; b) significant s in Landsat (units/year, , ); c) mapped changes from 1983 to 2010 from analysis done by Raynolds et al. (2014); d) significant s in TC1 (units/year, , ); e) significant s in TC2- (units/year, , ); f) significant s in TC3- (units/year, , ). The gray background lines are those of the Integrated Geoecological and Historical Change Map (Raynolds et al. 2014).

6 Table S1. Weighting applied to Landsat band data to perform the Tasseled-Cap Transformation (Crist 1985; Huang et al. 2002). Sensor Band 1 Band 2 Band 3 Band 4 Band 5 Band 7 TC TM TC TC TC ETM TC TC Table S2. Crosswalk from North Slope Science Initiative (NSSI) Land Cover map (Ducks Unlimited 2013) to combined land-cover types used in analysis of Alaska North Slope oilfield vegetation s (see Figure 2 in main paper_. NSSI Land-Cover Type Combined Land-Cover Type Abbreviation Notes Unclassified Unclassified N/A Not used in analysis. Bare Ground Barren or Partially Vegetated BA Sparsely Vegetated Barren or Partially Vegetated BA Open Water Water WA Fresh Water Marsh: Arctophila fulva Fresh Water Marsh: Carex aquatilis Aquatic Graminoid Tundra Aquatic Graminoid Tundra AG AG Wet Sedge Wet Sedge, Moss Tundra WS Mesic Herbaceous Tussock Tundra Tussock Shrub Tundra Moist Sedge, Prostrate-Dwarf- Shrub, Moss Tundra Moist Tussock-Sedge, Erect Dwarf-Shrub, Moss Tundra Moist Tussock-Sedge, Erect Dwarf-Shrub, Moss Tundra MS TS TS Mostly coastal mud flats. Combined with other bare or partially vegetated types in BA. Mostly riparian areas and dunes. Combined with other bare or partially vegetated types in BA. All unvegetated lakes, ocean and river water were included in WA. Only 1 pixel in study area. Combined with Carex aquatilis marshes in AG. Widespread, mainly in drained lake basins. Widespread and common in flat coastal plain, equivalent to WS. Not well defined as separate type. Combined with MS. Mainly on acidic sandy substrates west of the Colville River. Combined with other tussock types in TS. Uncommon within the mapped area, but does occur in warmer areas west of the Colville R. and

7 Mesic Sedge-Dwarf Shrub Tundra Dwarf Shrub - Dryas Dwarf Shrub Tundra Birch Ericaceous Low Shrub Moist Sedge, Prostrate-Dwarf- Shrub, Moss Tundra Moist Sedge, Prostrate-Dwarf- Shrub, Moss Tundra Moist Sedge, Prostrate-Dwarf- Shrub, Moss Tundra Moist Tussock-Sedge, Erect Dwarf-Shrub, Moss Tundra MS MS MS Low-Tall Willow Low to Tall Riparian Shrubland RS Alder Low to Tall Riparian Shrubland RS Coastal Marsh Wet Sedge, Moss Tundra WG TS to the east and south on acidic uplands. Combined with other tussock types in TS. We know from sampling in the study area that these types include mostly prostrate, dwarf shrubs (mainly Dryas integrifolia and prostrate willows and many mosses. Problematic, uncommon unit that occurs on dry river terraces, but is poorly separated spectrally from MS. Only 1.7 km 2 in SE of study area, combined with MS. Only 1.3 km 2, combined with other tussock types in TS. Occurs almost exclusively along rivers, combined with other shrub type in RS. Occurs almost exclusively along rivers, particularly the Colville River, combined with other shrub type in RS. Small coastal area west of Colville River, combined with other WS. Ice / Snow Ice/Snow N/A Not used in analysis. Burned Area Open Water WA Scattered misclassified pixels on lake edges, combined with WA.

8 Table S3. Trends in Landsat indices (units/year, ) within Alaska North Slope oilfield study area:, tasseled cap indices (TC1, TC2, TC3). Average for land-cover units, average for pixels with significant s, and percent of pixels within a unit with significant s. Land-cover units are shown in Figure 2 in the main paper, and are combined units from the North Slope Science Initiative (NSSI) Land Cover map (Ducks Unlimited 2013) (see Table S1 for crosswalk). Land- Cover Unit % TC1 % TC1 TC2 % TC2 TC1- TC2- TC3- TC3 p<.05 % TC3 PV AG WS MS TS RS OVERALL PV = Barren or Partially Vegetated, AG = Aquatic Graminoid Tundra, WS = Wet Sedge Tundra, MS = Moist Sedge, Prostrate-Dwarf-Shrub, Moss Tundra, TS = Moist Tussock-Sedge, Dwarf-Shrub, Moss Tundra, RS = Low to Tall Riparian Shrubland.

9 Table S4. Trends in Landsat indices (units/year, ) for different vegetation types within detailed map areas A,B,C in the Prudhoe Bay Oilfield shown in Figure 2 of the main paper. Trends for and tasseled-cap indices (TC1, TC2, TC3) are shown, with average for each vegetation type, average for pixels with significant s, and percent of pixels within a unit with significant s. % TC1 % TC1 TC2 % TC2 Vegetation Type TC1- TC2- TC3- TC3 p<.05 % TC3 AG AS AM WS MNT MAT LS NONE NONE 0.0 DF NONE NONE NONE 0.0 DC DT DG DB NONE BA AG = aquatic grass marsh; AS = aquatic sedge marsh (Scorpidium scorpioides or no moss); AM = aquatic moss marsh; WS = wet sedge tundra; MNT = moist, nontussock-sedge, dwarf-shrub tundra; MAT = moist, tussock-sedge, dwarf-shrub tundra; LS = moist, tussock-sedge, dwarf-shrub tundra; DF = dry, dwarf-shrub, fruticose-lichen tundra (acidic dry exposed sites); DC = dry, dwarf-shrub, crustose-lichen tundra; DT = dry, dwarfshrub, forb, lichen tundra (Dryas river terraces); DG = dry, dwarf-shrub, forb, grass tundra (river bars and stabilized dunes near sea coast); DB = dry forb barren (river bars, beaches, barrier islands); BA = barren.

10 Table S5. Trends in Landsat indices (units/year, ) for different surface form units within detailed map areas A,B,C in the Prudhoe Bay Oilfield shown in Figure 1 of the main paper. Trends for and tasseled-cap indices (TC1, TC2, TC3) are shown, with average for each vegetation type, average for pixels with significant s, and percent of pixels within a unit with significant s. Surface form unit % TC1 % TC1 TC2 % TC2 TC1- TC2- TC3- TC3 p<.05 % TC3 HH HCP LR LCP MP FS ST HU PI NP RE FL NONE TP SB NONE NONE NONE 0.0 EB NONE HH = high-centered polygons, center-trough relief > 0.5 m; HCP = high-centered polygons, center-trough relief < 0.5 m; LR = low-centered polygons, center-rim relief > 0.5 m; LCP = low-centered polygons, center-rim relief < 0.5 m; MP = mixed high-centered and low-centered polygons; FS = frost scars; ST = strangmoor and/or disjunct polygon rims (visible at 1:6,000); HU = hummocky terrain; PI = pingo; NP = nonpatterned ground; RE = reticulate pattern; FL = floodplain alluvium; TP = thermokarst pits (density greater than 4 pits per 3/8 inch circle on 1:6,000-scale photograph); SB = steep non-eroding bank; EB = actively eroding bank.

11 Table S6. Trends in Landsat indices (units/year, ) for different landform units within detailed map areas A,B,C in the Prudhoe Bay Oilfield shown in Figure 2 of the main paper. Trends for and tasseled-cap indices (TC1, TC2, TC3) are shown, with average for each vegetation type, average for pixels with significant s, and percent of pixels within a unit with significant s. % TC1 % TC1 TC2 % TC2 Landform unit TC1- TC2- TC3- TC3 p<.05 % TC3 TL RS PI AF SF ST SD NONE NONE NONE 0.0 BC NONE IS LP RI TL = drained thaw-lake; RS = residual surface; PI = pingo; AF = active floodplain; SF = stabilized floodplain ; ST = stream drainage; SD = sand dune; BC = bluff crest; IS = island; LP = lake or pond; RI = river.

12 Table S7. Trends in Landsat indices (units/year, ) for different natural and anthropogenic disturbance types within detailed map areas A,B,C in the Prudhoe Bay Oilfield shown in Figure 2 of the main paper. Trends for and tasseled-cap indices (TC1, TC2, TC3) are shown, with average for each vegetation type, average for pixels with significant s, and percent of pixels within a unit with significant s. % Disturbance Type TC1- TC1 % TC1 TC2- TC2 % TC2 TC3- TC3 p<.05 % TC3 Natural NV PV TP GW TG TW TR WF NONE GE SP NONE NONE WG WS Anthropogenic GR PR GP CF DF CT VR VT GD GC HD NONE NONE NONE 0.0

13 EX BT PI PO FE CA NONE NONE NONE 0.0 WT HP NONE Natural disturbance: NV = new vegetation in lake, PV = partial revegetation of disturbance, TP = increase in thermokarst pits, GW = aquatic grass marsh to water, TG = tundra to riparian gravel - eroding shore or deposited gravel, TW = tundra to lake water, TR = tundra to river water, WF = water filled troughs from advanced ice-wedge degradation far from infrastructure, GE = gullying and erosion from surface flow, SP = subsidence due to melting of pingo ice, transition from moist to wet, WG = water to gravel islands, WS = water to gravel shores. Anthropogenic disturbance: GR = gravel roads, PR = peat roads, GP = gravel pads, CF = continuous flooding, > 75% open water, DF = discontinuous flooding, less than 75% open water, CT = construction-induced thermokarst, VR = vehicle tracks - deeply rutted and/or with thermokarst, VT = vehicle tracks - not deeply rutted, GD = gravel and construction debris (> 75% cover), GC = gravel and construction debris (< 75% cover), HD = heavy dust or dust-killed tundra, EX = excavations of river gravels or other gravel sources, roadcuts or construction excavations, BT = barren tundra caused by previous flooding, PI = pipeline, PO = powerline and associated trails, FE = fence and associated trails, CA = canal, WT = water filled troughs from advanced ice-wedge degradation adjacent to infrastructure, HP= high-centered polygons from advanced ice-wedge degradation