One component of geomorphic complexity results from spatial heterogeneity in river corridors. The characteristics of this form of complexity have important implications for habitat and biodiversity, attenuation of downstream fluxes, resistance and resilience of river ecosystems, river processes, ability to characterize patterns and changes through time, and river management and restoration. Numerous measures of complexity have been applied to heterogeneity from spatial scales of bed grain size distribution to entire river networks. Studies explicitly incorporating geomorphic complexity have increased substantially since 2000, but there is no single, widely used metric of complexity. Despite increasingly explicit scientific appreciation of the importance of complexity in river corridors, public attitudes toward rivers continue to emphasize an attractive appearance, which commonly equates to a physically simple and homogeneous river corridor.
AdlerPBRaffDALauenrothWK (2001) The effect of grazing on the spatial heterogeneity of vegetation. Oecologia128: 465–479.
2.
AndersonJKWondzellSMGooseffMN. (2005), Patterns in stream longitudinal profiles and implications for hyporheic exchange flow at the H.J. Andrews Experimental Forest, Oregon, USA. Hydrological Processes19: 2931–2949.
3.
AnlaufKJJensenDWBurnettKM. (2011) Explaining spatial variability in stream habitats using both natural and management-influenced landscape predictors. Aquatic Conservation: Marine and Freshwater Ecosystems21: 704–714.
4.
AshmoreP (2013) Morphology and dynamics of braided rivers. In: WohlE (ed) Treatise on Geomorphology. Volume 9. Fluvial Geomorphology. Elsevier, 290–312.
5.
BaartmanJEMMasselinkRKeesstraSD. (2013) Linking landscape morphological complexity and sediment connectivity. Earth Surface Processes and Landforms38: 1457–1471.
6.
BakerDW (2009) Land use effects on physical habitat and nitrate uptake in small streams of the central Rocky Mountain region. PhD Dissertation, Colorado State University, Fort Collins, CO.
7.
BakerDWBledsoeBPPriceJM (2012) Stream nitrate uptake and transient storage over a gradient of geomorphic complexity, north-central Colorado, USA. Hydrological Processes26: 3241–3252.
8.
BartleyRRutherfurdI (2005) Measuring the reach-scale geomorphic diversity of streams: application to a stream disturbed by a sediment slug. River Research and Applications21: 39–59.
9.
BeckmanNDWohlE (2014) Carbon storage in mountainous headwater streams: the role of old-growth forest and logjams. Water Resources Research50: 2376–2393.
10.
BellmoreJRBaxterCV (2014) Effects of geomorphic process domains on river ecosystems: a comparison of floodplain and confined valley segments. River Research and Applications30: 617–630.
11.
BergNCarlsonAAzumaD (1998) Function and dynamics of woody debris in stream reaches in the central Sierra Nevada, California. Canadian Journal of Fisheries and Aquatic Sciences55: 1807–1820.
12.
BilbyREWardJW (1989) Changes in characteristics and function of woody debris with increasing size of streams in western Washington. Transactions of the American Fisheries Society118: 368–378.
13.
BlueBBrierleyG (2015) ‘But what do you measure?’ Prospects for a constructive critical physical geography. AreaDOI: 10.1111/area.12249.
14.
BoanoFHarveyJWMarionA. (2014) Hyporheic flow and transport processes: mechanisms, models, and biogeochemical implications. Reviews of Geophysics52: 603–679.
15.
BriggsD (1977) Sediments: Sources and Methods in Geography. London: Butterworths.
16.
BrierleyGJFryirsKA (2005) Geomorphology and River Management: Applications of the River Styles Framework. Oxford: Blackwell Publishing.
17.
BrooksAPGehrkePCJansenJD. (2004) Experimental reintroduction of woody debris on the Williams River, NSW: geomorphic and ecological responses. River Research and Applications20: 513–536.
18.
BrooksAPHowellTAbbeTB. (2006) Confronting hysteresis: wood based river rehabilitation in highly altered riverine landscapes of south-eastern Australia. Geomorphology79: 395–422.
19.
BrummerCJAbbeTBSampsonJR. (2006) Influence of vertical channel change associated with wood accumulations on delineating channel migration zones, Washington, USA. Geomorphology80: 295–309.
20.
BrunsdenD (2001) A critical assessment of the sensitivity concept in geomorphology. Catena42: 99–123.
21.
BrunsdenDThornesJB (1979) Landscape sensitivity and change. Transactions Institute of British Geographers4: 463–484.
22.
BullWB (1991) Geomorphic Responses to Climate Change. New York: Oxford University Press.
23.
BunteKAbtSR (2001) Sampling surface and sub-surface particle size distributions in wadable cobble- and gravel-bed streams for analyses in sediment transport, hydraulics and streambed monitoring. Report no. RMRS-GTR-74. Fort Collins, CO: USDA Forest Service.
24.
CadenassoMLPickettSTAGroveJM (2006) Dimensions of ecosystem complexity: heterogeneity, connectivity, and history. Ecological Complexity3: 1–12.
25.
CavalliMMarchiL (2008) Characterisation of the surface morphology of an alpine alluvial fan using airborne LiDAR. Natural Hazards and Earth System Science8: 323–333.
26.
ChinADanielsMDUrbanMA. (2008) Perceptions of wood in rivers and challenges for stream restoration in the United States. Environmental Management41: 893–903.
27.
ChonéGBironPM (2016) Assessing the relationship between river mobility and habitat. River Research and Applications32: 528–539.
28.
CollinsBDMontgomeryDRFetherstonKL. (2012) The floodplain large-wood cycle hypothesis: a mechanism for the physical and biotic structuring of temperate forested alluvial valleys in the North Pacific coastal ecoregion. Geomorphology139–140: 460–470.
29.
CompsonZGMierMZMarksJC (2009) Effects of travertine and flow on leaf retention in Fossil Creek, Arizona. Hydrobiologia630: 187–197.
30.
CorenblitDSteigerJGurnellAM. (2009) Control of sediment dynamics by vegetation as a key function driving biogeomorphic succession within fluvial corridors. Earth Surface Processes and Landforms34: 1790–1810.
31.
CraigLSPalmerMARichardsonDC. (2008) Stream restoration strategies for reducing river nitrogen loads. Frontiers in Ecology and the Environment6: 529–538.
32.
CurtisJAWrightSAMinearJT. (2015) Assessing geomorphic change along the Trinity River downstream from Lewiston Dam, California, 1980–2011. Scientific investigations report 2015-5046. Reston, VA: U.S. Geological Survey.
33.
DanehyRJRinglerNHStehmanSV. (1998) Variability of fish densities in a small catchment. Ecology of Freshwater Fish7: 36–48.
34.
EnsignSHDoyleMW (2006) Nutrient spiraling in streams and river networks. Journal of Geophysical Research111: G04009.
35.
Favis-MortlockD (2013) Systems and complexity in geomorphology. In: OrmeARSackD (eds) Treatise on Geomorphology. Volume 1. The Foundations of Geomorphology. San Diego, CA: Academic Press, 257–270.
FryirsKA (2015) Developing and using geomorphic condition assessments for river rehabilitation planning, implementation and monitoring. Wiley Interdisciplinary Reviews Water2: 649–667.
38.
FryirsKA (2016) River sensitivity: a lost foundation concept in fluvial geomorphology. Earth Surface Processes and Landforms. Epub ahead of print 1 January 2016. DOI:10.1002/esp.3940.
39.
FryirsKABrierleyGJ (2009) Naturalness and place in river rehabilitation. Ecology and Society14: 20.
40.
GirardPFantin-CruzILoverde de OliveiraSM. (2010) Small-scale spatial variation of inundation dynamics in a floodplain of the Pantanal (Brazil). Hydrobiologia638: 223–233.
41.
GooseffMNHallROTankJL (2007) Relating transient storage to channel complexity in streams of varying land use in Jackson Hole, Wyoming. Water Resources Research43: W01417.
42.
GrafWL (2006) Downstream hydrologic and geomorphic effects of large dams on American rivers. Geomorphology79: 336–360.
43.
GreeneSLKnoxJC (2014) Coupling legacy geomorphic surface facies to riparian vegetation; assessing red cedar invasion along the Missouri River downstream of Gavins Point Dam, South Dakota. Geomorphology204: 277–286.
44.
HarmonMEFranklinJFSwansonFJ. (1986) Ecology of coarse woody debris in temperate ecosystems. Advances in Ecological Research15: 133–302.
45.
HarrisRR (1988) Associations between stream valley geomorphology and riparian vegetation as a basis for landscape analysis in the eastern Sierra Nevada, California, USA. Environmental Management12: 219–228.
46.
HollingCS (1973) Resilience and stability of ecological systems. Annual Review of Ecology and Systematics4: 1–23.
47.
HoodGABayleySE (2008) Beaver (Castor canadensis) mitigate the effects of climate on the area of open water in boreal wetlands in western Canada. Biological Conservation141: 556–567.
48.
HookeJM (2013) River meandering. In: WohlE (ed) Treatise on Geomorphology. Volume 9. Fluvial Geomorphology. San Diego, CA: Academic Press, 260–288.
49.
HuangZNicholSLHarrisPT. (2014) Classification of submarine canyons of the Australian continental margin. Marine Geology357: 362–383.
50.
HugueFLapointeMEatonBC. (2016) Satellite-based remote sensing of running water habitats at large riverscape scales: tools to analyze habitat heterogeneity for river ecosystem management. Geomorphology253: 353–369.
51.
JeffriesRDarbySESearDA (2003) The influence of vegetation and organic debris on flood-plain sediment dynamics: case study of a low-order stream in the New Forest, England. Geomorphology51: 61–80.
52.
KlaarMJMaddockIMilnerAM (2009) The development of hydraulic and geomorphic complexity in recently formed streams in Glacier Bay National Park, Alaska. River Research and Applications25: 1331–1338.
53.
KondolfGM (2006) River restoration and meanders. Ecology and Society11: 42.
54.
KramerNWohlE (2015) Driftcretions: the legacy impacts of driftwood on shoreline morphology. Geophysical Research Letters42: 5855–5864.
55.
LamourouxNSouchonYHerouinE (1995) Predicting velocity frequency distributions in stream reaches. Water Resources Research31: 2367–2375.
56.
LaubBGBakerDWBledsoeBP. (2012) Range of variability of channel complexity in urban, restored and forested reference streams. Freshwater Biology57: 1076–1095.
57.
LeaDMLegleiterCJ (2016) Refining measurements of lateral channel movement from image time series by quantifying spatial variations in registration error. Geomorphology258: 11–20.
58.
LegleiterCJ (2014a) A geostatistical framework for quantifying the reach-scale morphology: 1. Variogram models, related metrics, spatial structure of river and relation to channel form. Geomorphology205: 65–84.
59.
LegleiterCJ (2014b) A geostatistical framework for quantifying the reach-scale morphology: 2. Application to restored and natural channels. Geomorphology205: 85–101.
60.
LeporiFPalmDBrannasE. (2005) Does restoration of structural heterogeneity in streams enhance fish and macroinvertebrate diversity?Ecological Applications15: 2060–2071.
61.
LiHReynoldsJF (1995) On definition and quantification of heterogeneity. Oikos73: 280–284.
62.
LiversBWohlE (2016) Sources and interpretation of channel complexity in forested subalpine streams of the Southern Rocky Mountains. Water Resources Research52: 3910–3929.
63.
LotspeichFBEverestFH (1981) A new method for reporting and interpreting textural composition of spawning gravel. Research note PNW-RN-369. Corvallis, OR: USDA Forest Service.
64.
LuckMMaumeneeNWhitedD. (2010) Remote sensing analysis of physical complexity of North Pacific Rim rivers to assist wild salmon conservation. Earth Surface Processes and Landforms35: 1330–1343.
65.
McCormickAFisherKBrierleyG (2015) Quantitative assessment of the relationships among ecological, morphological and aesthetic values in a river rehabilitation initiative. Journal of Environmental Management153: 60–67.
66.
McDowellPF (2013) Geomorphology in the late twentieth century. In: OrmeARSackD (eds) Treatise on Geomorphology. Volume 1. The Foundations of Geomorphology. San Diego, CA: Academic Press, 108–123.
67.
MillardTHHoganDLWilfordDJ. (2010) A method to assess fluvial fan channel networks, with a preliminary application to fans in coastal British Columbia. Geomorphology115: 286–293.
68.
MontgomeryDR (1999) Process domains and the river continuum. Journal of the American Water Resources Association35: 397–410.
69.
MurrayBFonstadMA (2007) Preface: complexity (and simplicity) in landscapes. Geomorphology91: 173–177.
70.
NelsonPABellugiDDietrichWE (2014) Delineation of river bed-surface patches by clustering high-resolution spatial grain size data. Geomorphology205: 102–119.
71.
O’ConnorJEJonesMAHaluskaTL (2003) Flood plain and channel dynamics of the Quinault and Queets Rivers, Washington, USA. Geomorphology51: 31–59.
72.
PalmerMAMenningerHLBernhardtE (2010) River restoration, habitat heterogeneity, and biodiversity: a failure of theory or practice?Freshwater Biology55: 205–222.
73.
PaolaC (1996) Incoherent structure: turbulence as a metaphor for stream braiding. In: AshworthPJBennettSJBestJL. (eds) Coherent Flow Structures in Open Channels. Wiley, 705–723.
74.
PeipochMBraunsMHauerFR. (2015) Ecological simplification: human influences on riverscape complexity. BioScience65: 1057–1065.
75.
PhillipsJD (2007) Perfection and complexity in the lower Brazos River. Geomorphology91: 364–377.
76.
PhillipsJD (2014) State transitions in geomorphic responses to environmental change. Geomorphology204: 208–216.
77.
PollockMMBeechieTJJordanCE (2007) Geomorphic changes upstream of beaver dams in Bridge Creek, an incised stream channel in the interior Columbia River basin, eastern Oregon. Earth Surface Processes and Landforms32: 1174–1185.
78.
PolviLEWohlE (2012) The beaver meadow complex revisited: the role of beavers in post-glacial floodplain development. Earth Surface Processes and Landforms37: 332–346.
79.
PolviLENilssonCHasselquistEM (2014) Potential and actual geomorphic complexity of restored headwater streams in northern Sweden. Geomorphology210: 98–118.
80.
PolviLEWohlEEMerrittDM (2011) Geomorphic and process domain controls on riparian zones in the Colorado Front Range. Geomorphology125: 504–516.
81.
ReidHEBrierleyGJ (2015) Assessing geomorphic sensitivity in relation to river capacity for adjustment. Geomorphology251: 108–121.
82.
RhoadsBL (2013) Process in geomorphology. In: OrmeARSackD (eds) Treatise on Geomorphology. Volume 1. The Foundations of Geomorphology. San Diego, CA: Academic Press, 190–204.
83.
RicciardiARasmussenJB (1999) Extinction rates of North American freshwater fauna. Conservation Biology13: 1220–1222.
84.
RoniPBeechieTPessG. (2015) Wood placement in river restoration: fact, fiction, and future direction. Canadian Journal of Fisheries and Aquatic Sciences72: 46–478.
85.
SawyerAHCardenasMBButtlesJ (2011) Hyporheic exchange due to channel-spanning logs. Water Resources Research47: W08502.
86.
SchwartzJSHerricksEE (2008) Fish use of ecohydraulic-based mesohabitat units in a low-gradient Illinois stream: implications for stream restoration. Aquatic Conservation: Marine and Freshwater Ecosystems18: 852–866.
87.
SchwoerbelJ (1961) Über die Lebendsbedingungen und die Besiedlung des hyporheischen Lebensraumes. Archiv für Hydrobiologie Supplement2–3: 182–214.
88.
ScottMLSkagenSKMeriglianoMF (2003) Relating geomorphic change and grazing to avian communities in riparian forests. Conservation Biology17: 284–296.
89.
ScownMWThomsMCDe JagerNR (2015a) Floodplain complexity and surface metrics: influences of scale and geomorphology. Geomorphology245: 102–116.
90.
ScownMWThomsMCDe JagerNR (2015b) Measuring floodplain spatial patterns using continuous surface metrics at multiple scales. Geomorphology245: 67–101.
91.
SheldonFThomsMC (2006) In-channel geomorphic complexity: the key to the dynamics of organic matter in large dryland rivers?Geomorphology77: 270–285.
92.
SinghAGualaMLanzoniS. (2012) Bedform effect on the reorganization of surface and subsurface grain size distribution in gravel bedded channels. Acta Geophysica60: 1607–1638.
93.
SmallMJDoyleMWFullerRL. (2008) Hydrologic versus geomorphic limitation on CPOM storage in stream ecosystems. Freshwater Biology53: 1618–1631.
94.
StanfordJALorangMSHauerFR (2005) The shifting habitat mosaic of river ecosystems. Verhandlungen des Internationalen Verein Limnologie29: 123–136.
95.
StewardsonMJMcMahonTA (2002) A stochastic model of hydraulic variations within stream channels. Water Resources Research38: 1007.
96.
ThorpJHThomsMCDelongMD (2008) The Riverine Ecosystem Synthesis: Toward Conceptual Cohesiveness in River Science. London: Academic Press.
97.
TimmRKWissmarRC (2013) Response to disturbance in a highly managed alluvial river: does it conform to La Chatelier’s general law?Geomorphology182: 116–124.
98.
ToothS (2000) Process, form and change in dryland rivers: a review of recent research. Earth-Science Reviews51: 67–107.
99.
VazPGMertenECWarrenDR. (2013) Which stream wood becomes functional following wildfires?Ecological Engineering54: 82–89.
100.
WainwrightJTurnbullLIbrahimTG. (2011) Linking environmental regimes, space and time: interpretations of structural and functional connectivity. Geomorphology126: 387–404.
101.
WallickJRGrantGELancasterST. (2007) Patterns and controls on historical channel change in the Willamette River, Oregon, USA. In: GuptaA (ed) Large Rivers: Geomorphology and Management. Chichester, UK: John Wiley and Sons, 491–516.
102.
WardJV (1989) The four-dimensional nature of lotic ecosystems. Journal of the North American Benthological Society8: 2–8.
103.
WebsterJRWaideJBPatternBC (1975) Nutrient recycling and the stability of ecosystems. In: HowellFG. (eds) Mineral Cycling in Southeastern Ecosystems. ERDA (CONF-740513), 1–27.
104.
WernerBTMcNamaraDE (2007) Dynamics of coupled human–landscape systems. Geomorphology91: 393–407.
105.
WestbrookCJCooperDJBakerBW (2006) Beaver dams and overbank floods influence groundwater-surface water interactions of a Rocky Mountain riparian area. Water Resources Research42: W06404.
106.
WestbrookCJCooperDJBakerBW (2011) Beaver assisted river valley formation. River Research and Applications27: 247–256.
107.
WohlE (2013) Wide Rivers Crossed: The South Platte and the Illinois of the American Prairie. Boulder, CO: University Press of Colorado.
108.
WohlEScottDN (2016, in press) Wood and sediment storage and dynamics in river corridors. Earth Surface Processes and Landforms.
109.
WohlELaneSNWilcoxAC (2015) The science and practice of river restoration. Water Resources Research51: 5974–5997.
110.
WooM-KWaddingtonJM (1990) Effects of beaver dams on subarctic wetland hydrology. Arctic43: 223–230.
111.
WuJLoucksOL (1995) From balance of nature to hierarchical patch dynamics: a paradigm shift in ecology. The Quarterly Review of Biology70: 439–466.
112.
WyżgaBOglęckiPRadecki-PawlikA. (2012) Hydromorphological complexity as a driver of the diversity of benthic invertebrate communities in the Czarny Dunajec River, Polish Carpathians. Hydrobiologia696: 29–46.
113.
YochumSEBledsoeBPDavidGCL. (2012) Velocity prediction in high-gradient channels. Journal of Hydrology424–425: 84–98.
114.
ZhangSGuoYWangZ (2015) Correlation between flood frequency and geomorphologic complexity of rivers network: a case study of Hangzhou, China. Journal of Hydrology527: 113–118.
