Physical Processes Elsevier US 0Mse01 29-3-2006 2:08P.M

Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 1

Section A

Physical Processes Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 2 Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 3

CHAPTER 1

Landscapes and Riverscapes Jack A. Stanford Flathead Lake Biological Station University of Montana

I. INTRODUCTION

Streams, rivers, and groundwater flow pathways are the plumbing of the continents. Water coalesces and flows downhill in surface channels and subsurface pathways in response to precipitation patterns and the dynamic form of river basins (catchments). Uplift of mountain ranges, caused by continental drift and volcanism, is continually countered by erosion and deposition (sedimentation) mediated by the forces of wind and water. Catchment landscapes are formed by the long geologic and biological history of the region as well as recent events such as floods, fires, and human-caused environmental disturbances (e.g., deforestation, dams, pollution, exotic species). The term landscape is used extensively, referring generally to the collective attributes of local geography. An expansive view of a stream or river and its catchment, including natural and cultural attributes and interactions, is the “riverscape.” For a stream ecologist, a riverscape view of a catchment (river) basin encompasses the entire stream network, including interconnection with groundwater flow pathways, embedded in its terrestrial setting and flowing from the highest elevation in the catchment to the ocean, with considerable animal and human modifications of flow paths likely along the way (Fausch et al. 2002). For example, the earth’s largest catchment, the Amazon River basin, occupies over half of the South American continent. Headwaters flow from small catchments containing glaciers and snowfields over 4300 m above sea level on the spine of the Andes Mountains to feed the major tributaries. The tributary rivers converge to form the mainstem Amazon, which flows from the base of the Andes across a virtually flat plate covered by equatorial tropical forest to the Atlantic Ocean. The altitude change is less than 200 m over the nearly 3000 km length of the mainstem river from the base of

4 Stanford

the Andes to the ocean. Because of the enormous transport power of the massive water volume of the Amazon River, some channels are >100 m deep. In other places along the river corridor the channel is >5 km wide, relatively shallow, and filled by sediment deposition (alluviation). Flood waters spread out over huge and heavily vegetated floodplains that support a myriad of fishes and other animals (Day and Davies 1986). The riverscape of the Amazon River, as among all rivers, was molded over time with the river cutting steep canyons through mountain ranges while building (alluviating) expansive floodplains where the slope of the river valley decreased. Rivers drain the continents; transport sediments, nutrients, and other materials from the highlands to the lowlands and oceans; and constantly modify the biophysical character of their catchment basins. These processes occur in direct relation to a particular catchment’s global position, climate, orography, and biotic character, coupled with spatial variations in bedrock and other geomorphic features of the riverscape. Within a catchment basin, stream channels usually grow in size and complexity in a downstream direction (Figure 1.1). The smallest or first-order stream channels in the network often begin as outflows from snowfields or springs below porous substrata forming ridges dividing one catchment from another. Two first-order streams coalesce to form a second-order channel and so on to create the network (Strahler 1963). A very large river, like the Amazon, often has several large tributaries, and each of those river tributaries may be fed by several to many smaller streams (Figure 1.1). Thus, each large catchment basin has many subcatchments. Erosive power generally increases with stream size. Boulders, gravel, sand, and silt are transported from one reach of the stream network to the next in relation to discharge and valley geomorphometry (e.g., slope and relative resistance of substrata to erosion). Expansive deposition zones (floodplains) form between steep canyons, where downcutting predominates. All rivers feature this basic theme of alternating cut and fill alluviation. Floodplains occur like beads on a string between gradient breaks or transitions in the altitudinal profile of the flow pathway (Leopold et al. 1964). Rivers of very old geologic age have exhausted much of their erosive power; mountains are rounded, valleys are broadly U-shaped, and river channels are single threads in the valley bottom with ancient, abandoned floodplains called terraces rising on either side. Whereas, in geologically young, recently uplifted catchments, stream power and associated erosive influence on valley form is great; mountains are steep-sided, valleys narrowly V-shaped, and the river spills out of many interconnected channels on alluvial floodplains in aggraded areas during flooding. Of course, no two rivers are exactly alike, but a general longitudinal (upstream to downstream) pattern of cut and fill alluviation usually exists (Figure 1.1A). Many small and usually erosive streams coalesce in the headwaters to form a main channel that grows in size and power with each primary tributary. The main channel alternately cuts through reaches constrained by bedrock canyons and spills water and sediments onto aggraded floodplain reaches where the river may be quite erosive (cutting) in one place and time and building sedimentary structures (filling) in another; thus, creating a suite of dynamic habitats for biota. The riverscape at any point within the stream network is four-dimensional (Figure 1.1B). The river continuum or corridor from headwaters to ocean is the longitudinal (upstream to downstream) dimension. The second dimension is the transitional area from the river channel laterally into the terrestrial environment of the valley uplands (aquatic to terrestrial dimension). Except where rivers flow over impervious bedrock, some amount of porous alluvium is present within the channel owing to erosion at Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 5

Chapter 1 • Landscapes and Riverscapes 5

A B Headwaters

Headwater Canyon

Montane Floodplain

Montane Canyon

Piedmont Valley Floodplain

Piedmont Canyon

Coastal Key Floodplain Longitudinal

teral La

Delta-Estuary Vertical

FIGURE 1.1 Idealized view of (A) the stream network showing the coalescence of headwater streams, which begin at snowfields or groundwater discharge portals, and the longitudinal distribution of floodplains and canyons (“beads on a string’’) within a headwater to ocean river ecosystem and (B) the 3D structure of alluvial floodplains (beads), emphasizing dynamic longitudinal, lateral and vertical dimensions, and recruitment of wood debris. The groups of arrows in (A) indicate the expected strength of ground- and surfacewater exchange (vertical),channel and floodplain (lateral) interactions,and upstream to downstream or longitudinal (horizontal) connectivity in the context of (B). The floodplain landscape, contains a suite of structures (see Table 1.1) produced by the legacy of cut and fill alluviation as influenced by position within the natural-cultural setting of the catchment.The parafluvial zone is the area of the bankfull channel that is to some extent annually scoured by flooding. The hyporheic zone is defined by penetration of river water into the alluvium and may mix with phreatic ground water from hillslope or other aquifers not directly recharged by the river. Alluvial aquifers usually have complex bed sediments with interstitial zones of preferential groundwater flow sometimes called paleochannels. Assemblages of biota may be segregated in all three spatial dimensions including riparos (streamside or riparian), benthos (channel bottom), hyporheos (interstitial within the stream bed-sediments) and phreatos (deep groundwater) in addition to fish and other organisms in the water column of the river (from Stanford et al. 2005b).

points upstream. Hence, water from the river may penetrate deeply into the substrata of the river bottom. Moreover, substrata of floodplains are composed of alluvial gravels and/or sands and silts, which allow lateral flow of river water. Hence, interstitial flow pathways constitute a vertical dimension in the river channel and on the floodplains. All of the physical dimensions change in size over time (the fourth dimension), as floods and droughts alter hydrology, sediment transport, and distribution of vegetation and other biota (Ward 1989, Stanford et al. 2005b). Plants and animals are distributed in relation to biophysical gradients expressed by the four-dimensional nature of the stream network within catchment basins. For example, certain species of aquatic insects reside only in the cold, rocky environs of cascading Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 6

6 Stanford

headwater streams in the high mountains (rhithron environments), whereas other species are found only in the much warmer waters of the often sandy, turbid, and meandering reaches of the lowlands near the ocean (potamon environments) (Ward 1989). Thus, riverine biota have distinct preferences for specific environmental conditions that are optimal only at certain locations within longitudinal (upstream-downstream), lateral (aquatic-terrestrial), vertical (surface-ground water), and temporal (certain time) gradients that characterize lotic ecosystems (Figure 1.1). Andrewartha and Birch (1954) observed that the essence of ecology is understanding the distribution and abundance of biota. Because environmental conditions at any point in a stream are continuously influenced by conditions at points upstream, biophysical controls on distribution and abundance of riverine biota must be examined in the context of the stream and its landscape setting (Hynes 1975). A key point is that the riverscape is not static. Rather, it is a dynamic, constantly shifting mosaic or catena of interconnected habitats (Table 1.1) that are created, modified, destroyed, and rebuilt by the interactive processes of cut and fill alluviation mediated by flooding and moderated by riparian vegetation. Trees fall into the channel as powerful flood flows erode floodplain benches covered by forests. The trees obstruct flow, causing deposition of sediments that subsequently allow seedling establishment. Dense growths of young trees catch more sediment, building new floodplain benches and gradually growing into riparian forests. Yet, flooding may knock them down again. Moreover, young riparian trees have to grow fast enough to keep their roots near or in the water table as flooding abates and the volume of the alluvial aquifer declines or they will die. Indeed, the changing volume of the alluvial aquifer and associated rise and fall of the water table coherent with flow in the channel is another important habitat forming process of alluvial floodplains. Overland flooding from the channel to the floodplain is obvious as bankfull flow is exceeded and water spills out of the channel network. Flooding from below ground is less intuitive, but in gravel-bed rivers the initiation of overbank flooding usually is preceded by filling of the alluvial aquifer to the extent that the surface is saturated and hyporheic water erupts into swales and abandoned channels, creating wetlands and spring brooks. Change from dry to wet condition associated with above and below ground flooding is called the flood pulse, and it allows aquatic and terrestrial biota to use the same space but at different times, thus vastly increasing biodiversity and bioproductivity of the riverscape (Junk 2005). The Nyack Floodplain of the Middle Flathead River in Montana is a great example of how plants and animals respond to the flood pulse. This floodplain is very dynamic; the main channel is never in the same place for very long (Figure 1.2). High-resolution remote sensing, coupled with very detailed ground truth studies, have allowed scientists to map the distribution, abundance, and growth of biota within the shifting habitat mosaic (sensu Stanford et al. 2005b) of this floodplain in great detail (Figure 1.3). The parafluvial zone expands and contracts with flooding as cottonwood, willows, and alder generate seedlings during periods of minimal flooding and are washed away during big floods. The orthofluvial zone is built up by deposition of fine sediments, allowing old growth stands of cottonwood and spruce to develop. Wetlands exist in depressions throughout the floodplain, further increasing habitat diversity. Nearly 70% of the vascular plants known in the region occur on this floodplain as a consequence of the shifting habitat mosaic. Other groups of biota are similarly diverse. Thus, the floodplain is in a constant state of change, allowing many species to coexist (Stanford et al. 2005b). To underscore this point, again consider the Amazon. This great river has existed for millions of years, allowing its biota to evolve highly specialized life histories and Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 7

Chapter 1 • Landscapes and Riverscapes 7

TABLE 1.1 Linked Structural (habitat) Elements of Floodplain River Landscapes. Channel and ﬂoodplain elements overlap spatially and interact temporally, but time frames differ among rivers. Perirheic habitats are lateral lakes and ponds fed by groundwater that occur on the ﬂoodplains of large tropical rivers as described by Mertes (1997). Not all of these elements will necessarily be present on every stream or river because the hydrogeomorphic setting varies even within the same river system (from Stanford et al. 2005b).

FLOODPLAIN — entire valley-bottom area that is capable of flooding, including the channel network. Parafluvial catena — recently reworked by bankfull flooding, usually with driftwood throughout.

− Permanently connected channels (eupotamon) — primary, secondary, tertiary channels with characteristic features, such as thalweg, rapids, shutes, riffles, pools, runs, glides, tailouts, shallow shorelines, channel separation nodes, channel confluence zones, backwaters or side-arms. Parafluvial zone — area of annual sediment scour and deposition by floods and wind; with early successional riparian vegetation. flood channels — seasonally connected overflows. islands — midchannel areas of sediment accretion, often mediated by wood. bars and levees — elevated accretion features. spring brooks (parapotamon) — channelized flow of emergent hyporheic groundwater in flood channels. ponds or scour holes (plesiopotomon) — perched surface water or emergent hyporheic (groundwater). Tributary channels — permanent or seasonally disconnected side flows.

Orthofluvial catena — reworked only by big floods or ice jams but frequently inundated, usually with over bank sediment deposits, driftwood, and a riparian vegetation mosaic of age-segregated patches. Active accretion areas — rapidly enlarging, with variable but mainly well-drained, thin, organic-poor, or variable soils associated with and interfluvial ridge and swale microtopography; may be dissected by flood channels that may contain Increasingly terrestrial spring brooks, scour pools, and other parafluvial features. scrolled (point) bars — continual lateral accretion, usually with woody vegetation precisely age-segregated. shelves of recent origin — continual accretion, sometimes by driftwood-mediated island aggregation; may have spring brooks, ponds, marshes (paleopotomon) in swales and depressions of abandoned channels and usually dominated by mid-late successional riparian forests or wet meadows. Passive accretion areas — slowly enlarging, with deeper organically enriched soils

Perirheic habitats associated with swale and ridge microtopography. shelves of ancient origin — slow accretion associated with extreme flooding into late successional (gallery) riparian forests; may have spring brooks, oxbows, pans, lakes, billabongs, marshes, bogs or muskegs (paleopotomon) in swales and depressions associated with gradual topographic changes resulting from sedimentation and organic filling of long-abandoned, ancient channels. −−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−−

floodplain-terrace transition zone — mixed upland and floodplain vegetation; ← often with spring brooks or wet lands in wall-based flood channels.

TERRACES — ancient floodplains, disconnected from the active floodplain system by incision and no longer inundated by floods; dominated by terrestrial vegetation.

HILL SLOPES (VALLEY WALLS) — terrestrial, but may be substantially influenced by microclimatic influences of the floodplain; may have slope wetlands from with disjunctive floodplain vegetation. Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 8

8 Stanford

FIGURE 1.2 (A) A satellite multispectral image of the Nyack Floodplain habitat catena (Middle Flathead River, Montana 2004). Most, but not all, elements given in Table 1.1. are found on this floodplain. The floodplain extends laterally to both valley walls and is essentially a bowl filled with gravel and rock with a thin veneer of fine sediment and gradually developing soils on the higher-elevation benches that are not scoured by flood flows. Much of the gallery forest of cottonwood and spruce has been cleared for hay farming. Owing to the porous nature of the valley bedsediments, a legacy of river deposition since glaciation, river water downwells into the alluvial aquifer beginning at the upstream knickpoint where the river becomes unconstrained by bedrock. The downstream knickpoint defines entry into another bedrock- constrained canyon, which impounds the alluvial aquifer, allowing it to intersect the surface creating spring brooks and wetlands as water flows from the aquifer back into the river. (B) Here the position of the main channel during 1945–2004 has been color coded to emphasize the dynamic nature of the river (Flathead Lake Biological Station, unpubl. data).

morphologies in response to long-term dynamics of the river environment. Seemingly countless aquatic and semiaquatic species coexist, each trying, and variously succeeding, to grow and reproduce in accordance with evolved life history traits and within the myriad of environmental gradients expressed by the dynamic course of the river through the massive catchment basin. For example, the adaptive radiation of Amazonian fishes is astounding, ranging from deep-water specialists that reside in the dark depths of the scoured channels to species that reproduce exclusively in the floodplain forests during floods (Junk et al. 2000, Lowe-McConnell 1987, Petrere 1991). Perhaps even more profound are interpreta- tions of satellite-derived images that strongly suggest the enormously complex and highly evolved rain forests of the Amazon Basin are composed of a mosaic of successional stages created by the river cutting and filling its way back and forth across this huge landscape century after century (Colinvaux 1985, Salo et al. 1986). We can conclude from studies on the Amazon and many other river systems that the first task of a river ecologist is to determine the appropriate scale of study to answer any particular question at hand (Poole 2002). Do I need to examine the problem in the Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 9

Chapter 1 • Landscapes and Riverscapes 9

Vegetation Legend

Shadows Deciduous Trees Herbs and Seedlings Grasses Conifer Trees Cobble Polestand Cottonwood

Channel Hydraulics Legend Velocity (m/s) .15.5 1.0 1.5 2.0 .25 .50 .75 1.5 Depth (m) 2.5

FIGURE 1.3 (A) Hyperspectral data for the image in Figure 1.2.A. of the Nyack Floodplain have been classified into various vegetation types (1 m resolution) using geographical information software (GIS) and validated using ground truth surveys. Inset (B) is a high-resolution digital image that has been classified in (C) showing the distribution of depth and velocity of the water in the image along with the same vegetation types as in (A). Classification of such attributes allows spatially explicit determination of the distribution and abundance of floodplain habitat used by fishes and wildlife (Flathead Lake Biological Station, unpubl. data).

context of the entire river continuum from headwaters to the ocean or will a particular reach or even a particular riffle or pool suffice? Moreover, this dilemma of spatial scale is complicated by the fact that the full range of biophysical features of rivers may change suddenly as a consequence of intense, unusual events like very large floods, extended droughts, catchmentwide fires, earth- quakes, volcanic eruptions, and other natural phenomena that may radically change conditions reflected by the long-term norm (Schumm and Lichty 1956, Stanford et al. 2005b). So what time period needs to be encompassed by a study in order to adequately understand the ecological significance of natural disturbance events? And, of course, natural variation in time and space is superimposed upon environmental change induced by human activities in catchment basins. Native people have always been a part of riverscapes worldwide, shaping it to their needs by diverting flows for irrigation of crops or increasing wetland plants, burning forests to increase berry shrubs and harvesting riverine biota. Native societies simply moderated the shifting habitat mosaic, whereas modern societies have vastly altered the process. Flows in all of the larger and most of the smaller rivers in the temperate latitudes of the world now are regulated by dams and diversions, and the tropics are under siege (Dynesius and Nilsson 1994, Nilsson et al. 2005). Reduced volume and altered seasonality of flow radically change the natural habitat template, eliminating native species and allowing invasion of nonnatives. Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 10

10 Stanford

In many cases water from dams is discharged from the bottom of reservoirs, drastically changing temperature patterns and armoring the river bottom by flushing gravel and sand and leaving large boulders firmly paving the bottom. Problems related to flow regulation in other cases are exacerbated by pollution and channelization (Petts 1984). A wide variety of other human effects can be listed (Table 1.1). The cumulative effect is the severing or uncoupling of the complex interactive pathways that characterize the four-dimensional shifting habitat mosaic of riverscapes. Generally, the result is a vastly less dynamic environment than occurred naturally that substantially compromises biota that are adapted to the shifting habitat mosaic often allowing invasion of nonnative, noxious species (Stanford et al. 1996).

II. GENERAL DESIGN A. Analysis at the Riverscape Scale

The purpose of this chapter is to provide a riverscape or ecosystem context for the other chapters in this book, which teach detailed and more site-specific analyses of river ecological processes and responses. The premise is that few river research and management questions can be answered without considering riverscape attributes and dynamics and very often, issues outside the catchment basin may also be very important. Indeed, almost all natural resource management questions have to be addressed in a whole basin or river ecosystem context owing to overlapping jurisdictions and the interactive nature of ecological processes that provide riverine goods (clean water, fisheries, wildlife) and services (transportation, water power, floodplain fertilization) that humans require. However, ecosystem boundaries are permeable with respect to energy and materials flux and often are best determined by the nature of the ecological issue or question of concern (Stanford and Ward 1992). Consider the problem of conserving wild salmon around the world. Wild salmon have steadily declined worldwide due to overharvest and vastly altered habitat conditions in many of their natal rivers. For example, at least 20 million Pacific salmon and steelhead historically returned to the Columbia River to spawn. Over 200 different runs (populations) of the five most abundant species occurred as a result of thousands of years of adaptation to the shifting habitat mosaic and the high productivity of the very complex riverscape of this huge (567000 km2) catchment basin. Adult salmon returned with great fidelity to specific sites along the entire river corridor, including headwater streams and lakes in many of the tributaries (e.g., Snake River Subbasin). Juveniles moved around a lot, often focusing on floodplain habitats and grew on the rich food sources provided by the shifting habitat mosaic. Populations of some species stayed in the river only a few months, while others stayed for three to five years. This same life history plasticity occurred in the ocean with some returning to spawn after only one or two years, while others such as the huge Columbia River chinook (locally called June hogs for the timing of the run and their 25 kg+ body size) fed for several years in the ocean before returning. This life history plasticity underscores the ability of salmon species to adapt their life cycle to local conditions encountered. The Columbia River encompasses 15 ecoregions, thus presenting many different shifting habitat venues for salmon to use, and the result was a very high diversity of locally adapted populations. Entrainment of salmon carcasses in the riparian zone increased fertility (salmon die after spawning, steelhead do not) in addition to providing food for a wide variety of wildlife and humans living along the Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 11

Chapter 1 • Landscapes and Riverscapes 11

river and its many tributaries. Thus, the predevelopment Columbia was a natural salmon factory that supported thousands of native people (Stanford et al. 2005a, Williams 2006). Of course, today the Columbia River and almost all of its tributaries are completely harnessed by hundreds of dams that vastly alter natural flow patterns. Almost the entire mainstem is impounded by hydropower operations making salmon migration problematic. Floodplains either are flooded by reservoirs or severed from the river channel by highways, railroads, and encroaching towns and cities. Farms and industries of all sorts have been developed by diverting water from the tributaries and the mainstem. Billions of dollars have been spent to recover salmon in the Columbia River since 1990 to little avail. Indeed, only one really robust run remains, fall chinook that spawn and rear to smolts (ocean going juveniles) in the Hanford Reach, the last free flowing stretch of the mainstem river (Stanford et al. 2005a, Williams 2006). The situation is not much better in most of the other salmon rivers of the world, except those in the far north where the shifting habitat mosaic remains unaltered by human activities. Salmon have been lost altogether in most European Rivers such as the Rhine River where they were once abundant. But owing to their iconic and economic status in local cultures along rivers where salmon were once abundant, people want the salmon back and are willing to pay for it. The challenge for river ecologists is how to allow use of the rivers for the full array of human demands and at the same time provide habitat for salmon. At least two main issues must be considered. First, one has to realize that the ecosystem of the salmon includes the entire river system as well as its estuary and a large area of marine environment, and that for Pacific salmon by example, means most of the North Pacific Ocean where they migrate from one feeding area to another depending on ocean conditions. So far, managers have not tailored harvest of salmon to account conservatively for variation in ocean, estuary, and riverine conditions that salmon will encounter during their long life cycle, and the result has been years of overkill that has eventually reduced the runs to the point that they cannot be sustained in spite of their natural plasticity to environmental variation. Second, the shifting habitat mosaic that salmon require in freshwater has to be provided by restoring normative flow to the natal rivers (Stanford et al. 1996, Hauer et al. 2003, Hauer and Lorang 2004, Stanford et al. 2005a). In many systems, like the Columbia, this can only be reasonably done on certain tributaries that do not have large hydropower dams and other infrastructures that people are not willing to give up in spite of general favoritism for salmon. Other issues such as climate change and use of hatcheries to mitigate lost habitat also are problematic (for more information about salmon, see www.wildsalmoncenter.org). On a smaller scale, but with equally interactive research and management issues in river ecology, is the Flathead River-Lake ecosystem in northwestern Montana and southeastern British Columbia, Canada (Stanford and Ellis 2002). It is a large (22241 km2) subcatchment of the Columbia River that was historically unavailable to salmon owing to natural barrier falls that prevented upstream migration. The catchment encompasses small urban and agricultural lands on the piedmont valley bottom, extensive national (US) and provincial (BC) forests with forest production and wilderness management zones, and the western half of the Glacier-Waterton International Peace Park, an International Biosphere Reserve and World Heritage Site. The altitudinal gradient extends some 3400 m from the highest points on the watershed to Flathead Lake. Indeed, the flow of the river begins on Triple Divide Peak, the crown of the continent where three of the great rivers (Columbia, Saskatchewan, and Missouri) of North America begin. The riverscape of the Flathead is multifaceted, with crystal mountain streams cascading through steep mountain valleys Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 12

12 Stanford

that contain abundant populations of Rocky Mountain wildlife, including one of the two last populations of grizzly bears in the United States (the other is in the Greater Yellowstone Ecosystem). The river system includes the Nyack Floodplain just described, where the concept of the shifting habitat mosaic was developed and other expansive floodplains along each tributary and the main stem in the Flathead Valley that flows into 480 km2 Flathead Lake, the largest lake in the western United States and among the cleanest in the world for large lakes that have significant human populations in the catchment basin. But the Flathead is under the same pressures that most river and stream systems endure. The limnology of Flathead Lake and its river system has been studied for over 100 years by scientists at the Flathead Lake Biological Station of the University of Montana. This record clearly shows that water quality is gradually declining in direct relation to development of the human infrastructure in the basin. In recent decades, the decline in water quality has accelerated in response to very rapid population expansion. Driven by strong desire to sustain high water quality, particularly the amazing transparency of Flathead Lake, and the very clear demonstration of change for the worse by the scientists, citizens of the Flathead supported construction of modern sewage treatment plans throughout the catchment and effectively implemented land use regulations to minimize diffuse runoff of pollutants from cities, farms, and logging operations. This is a success story for river management, although continued vigilance and careful river and lake monitoring is required. However, a continuing major problem for river ecologists in the Flathead is the change in the food web structure of Flathead Lake. Species of fish and invertebrates were introduced to increase fishing opportunities, actions that were scientifically uninformed. Indeed, the abundant native trout, the cutthroat, began to decline when landlocked red salmon (kokanee) were introduced, along with lake trout, lake whitefish, bass, and other species. The native predatory fish, the bull charr, adapted to feeding on kokanee as their native prey, the cutthroat, declined. Bull charr (and cutthroat trout) migrate from the lake to specific tributaries to spawn. Juveniles stay in the river system for several years before migrating to the lake to mature. Thus, the life cycle is rather like salmon in that the lake and river system encompass the bull charr’s life history ecosystem. Bull charr persisted happily in Flathead Lake until mysid shrimp (Mysis relicta) were introduced with the thought of increasing productivity of kokanee through added mysid forage. The introduction backfired badly because it turned out that the mysids ate the food of the kokanee, but the kokanee could not in fact forage on mysids because the mysids were only active at night, whereas kokanee are daytime feeders. This effectively eliminated the formally abundant kokanee from the lake. At the same time the mysids provided abundant new forage for lake trout and lake whitefish that were previously impoverished by having poor food resources for early life stages and were only very slowly expanding. The new mysid forage was ideal for juvenile lake trout and lake whitefish and allowed these species to expand rapidly at the expense of the bull trout, which declined precipitously. Today the lake is dominated by nonnative fish. The native bull charr, cutthroat, and other native fishes are in danger of extirpation from the system. In addition, the now abundant nonnative species have emigrated upstream and colonized lakes in Glacier National Park, presenting yet another dilemma for river managers. The Federal Endangered Species Act and the charter of the National Park system in the United States require conservation and protection of native species. This will be decidedly problematic in the Flathead, owing to seemingly irreversible food web changes promulgated by past management mistakes. Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 13

Chapter 1 • Landscapes and Riverscapes 13

These examples underscore the importance of understanding river and stream systems in a riverscape ecosystem context. A clear definition of the ecosystem boundaries that influence environmental problems is required. The bottom line is that today’s stream ecologist must be broadly trained, attuned to a multidisciplinary, riverscape approach to problem solving, and fully informed scientifically to do the job right.

III. SPECIFIC METHODS A. BasicMethod1: BoundariesandHydrographyoftheCatchmentBasin

Catchment boundaries are the ridges that separate a catchment basin from those adjacent. Technically, the catchment boundaries should be termed watersheds. However, in the United States watershed often is considered synonymous with catchment basin. The hydrography (spatial distribution of aquatic habitats) of a catchment basin can be conve- niently examined at 1:24,000 scale using maps available from the United States Geological Survey.

1. Using larger-scale maps of your research area, determine catchment basin boundaries for a region of at least 10000 km2. Choose one catchment of at least 100 km2 area for detailed examination. Using a planimeter, determine the total area of the basin. 2. Note the stream network, shown in blue on most maps. Compare the detail of the catchment on different scale maps. The smallest streams begin at higher elevations (e.g., snowfields, lakes, wetlands, or springs). Groundwater aquifers often erupt from hillsides via upslope infiltration of precipitation through porous soils or bedrock. In many cases the smallest stream channels are shown as broken lines, which indicate that surface flow is intermittent. 3. If many intermittent stream channels are shown, the catchment basin is either very dry or the substrata are very porous. In both mesic (wet) and xeric (dry) landscapes, a large amount of the runoff may follow subterranean (groundwater) pathways through porous substrata (see Stanford et al. 2005b). Differentiate intermittent and permanent stream channels in your catchment. 4. An important point to keep in mind is that the drainage network really is a geohydraulic continuum; that is, the stream corridor has both surface and groundwater components, and these interactive pathways are hydrologically and ecologically interconnected (Gibert et al. 1994). Water flowing at the surface at one place may be underground at another, depending on the geomorphology of the catchment basin and the volume and timing of rainfall or snowmelt. Hence, interaction zones between surface and groundwaters are fundamental attributes of landscapes and are very germane to stream ecological studies. Compare topographic, geologic, and groundwater maps of your catchment and identify potential areas of near surface ground waters that may be fed by surface waters or discharge into the stream network. 5. Stream order is determined by the coalescence pattern (see Figure 1.1 and Chapter 4, Figure 4.1). Two first-order streams converge to form a second-order stream, two second-order tributaries form a third-order stream, and so on. Network density is related to geologic origin of the basin, time since uplift, precipitation patterns, precipitation history, types of vegetation present, and Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 14

14 Stanford

resistance of substrata to erosion and infiltration. Lay out a series of maps covering the study catchment at 1:24,000 scale. Overlay the maps with clear plastic or acetate sheets. On the plastic sheets, color-code the different stream orders with markers and tabulate them on a data sheet. Measure length of all streams within the catchment, using a map wheel. Simply trace the stream corridor with the map wheel starting at zero and reading the distance on the appropriate scale of the wheel. Calculate drainage density of the catchment as total stream length divided by total area of catchment. 6. Observe the altitudinal gradient from highest to lowest elevation in the catchment. Carefully consider the density of topographic isopleths (lines of equal elevation). Where they converge closely adjacent to and across the stream channel, canyon segments exist. More widely spaced isopleths indicate flatter topography. Use the acetate sheets overlaying the topographic maps set up in step 5 to locate gradient breaks. 7. Identify canyons (downcutting channels confined by bedrock walls) and alluvial (aggraded, unconfined channels with wide, terraced floodplains) stream segments. In many cases alluvial deposits will be shown by special designations on the maps. Check the map key for such designations. In alluvial zones you may observe that the stream channels begin to braid, which suggests major deposition and floodplain development. On alluvial reaches of bigger streams, the general structure of the floodplains will likely be evident in the form of active zones of flood scour and terraces at higher elevations along the channel. Using elevation data from the topographic maps, plot the stream profile from highest to lowest elevation (x-axis = distance downstream; y-axis = elevation). Label the major gradient breaks and alluvial reaches. 8. Streams may flow into lakes or wetlands. In some cases wetlands may remain where lake basins have filled with sediments. In glaciated landscapes, lakes may occur in high-altitude cirques; larger, often very deep lakes may occur singly or in a series in the glaciated mountain valleys. Many lakes and wetlands are fed and drained by groundwater and determination of underground flow pathways may require geohydrologic surveys. Consult Wetzel (2001) for detailed descriptions of the types of lakes and modes of origin. The main point here is to note the position and potential influence of lakes on the stream network of your catchment basin. Lakes function as sinks for fluvial sediments, nutrients, and heat. Streams flowing from lakes may well be very different than inflowing streams. Manmade reservoirs function in similar fashion, except that ecological influences on rivers below the dams will depend on the depth and mode of water release from the dams (Stanford et al. 1996, Poff et al. 1997). Tabulate lakes and reservoirs in your catchments, noting elevation, area, and other available data (e.g., volume, flushing rate).

B.BasicMethod2: OtherLandscapeAttributesoftheCatchmentBasin

The maps provided likely will show surficial geology, groundwater resources, broad vegetation categories, precipitation patterns, and human infrastructures (roads, pipelines, dams, railroads, urban areas, or individual buildings, etc.). Systematic summarization of these features in relation to the hydrography will provide valuable insights about potential influences on water quantity and quality and constraints on distribution and abundance of riverine biota. For example, an understanding of the general geology of Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 15

Chapter 1 • Landscapes and Riverscapes 15

the catchment basin will provide insights into discharge, water chemistry, distribution of biota, and other attributes of the catchment basin that likely will be encountered in fieldwork. Igneous and metamorphic rocks generally do not dissolve much in water, and, hence, surface waters draining such formations have low dissolved solids and little buffer capacity, whereas waters from limestone formations generally may be expected to contain high amounts of dissolved solids and be very well buffered. Land use patterns inferred from the distribution of human infrastructures shown on the maps can be corroborated from aerial photographs and satellite images. Google Earth and other Internet map tools allow a quick view of the riverscape (http://earth.google.com/). If the photos are available in a time series, changes in hydrography (e.g., channel migration on floodplains) as well as changes in land use patterns can be observed.

1. Using a map wheel and planimeter for the maps (may use digitizing tablet and computer if available) and a stereoscope for aerial photos of known scale, determine the lengths and areas of various features on the landscape of the river catchment you have chosen for study. Create a table or computer spreadsheet in which you can record the different landscape attributes identified in the steps below. Record the features by stream length, area, or other spatial measures. This will provide a basis for a general description of the study catchment and landscape attributes that may influence ecological processes and responses within the stream network. 2. Compare the catchment basins you have identified on the topographic maps with geologic maps of the region. On granitic and other “hard rock” mountains, runoff usually is dominated by surficial flow, whereas limestone and other sedimentary and volcanic formations may allow considerable infiltration and runoff may predominately follow groundwater pathways to portals back to the surface at lower elevations. Subsurface drainage networks dominate in karst (cavernous limestone) landscapes (see Mangin 1994). Tabulate the major geologic formations by type and percent of catchment basin area. Use a planimeter to determine areas of different geologic formations. 3. Determine vegetation cover patterns within the catchment basin. At a minimum the topographic maps should show forest or grassland areas in green and exposed bedrock or other nonvegetated (e.g., clear-cut forest stands) areas in white. Glaciers and wetlands likely will have special designations shown in the map key. Vegetation maps of your catchment may be available or you may be able to use aerial photos to determine the general pattern in comparison to the topographic maps. Using all available maps and photos determine at a minimum riparian (stream side), wetland, and upland (forest and grassland) ground cover for the entire catchment basin. For montane regions it is instructive to differentiate forest types with respect to altitude (e.g., riparian, upland forest, subalpine forest, alpine). Again use the planimeter to determine areas of cover types and record percent of basin area by type. 4. Examine the stream corridors on the topographic maps for features created by human activity, such as revetments, bridges, irrigation diversions or returns, mines, and other industrial sites. All of these may change flow patterns or otherwise influence the natural attributes of the stream corridor. On the acetate sheets, color-code stream segments by type of alteration or land use. Tabulate percent of stream corridor and/or catchment basin potentially influenced. 5. If aerial photos are available, verify all the features you have identified in the catchment basin(s) from interpretation of maps. Add notes for features more Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 16

16 Stanford

evident in the photos, such as riparian forests or stream channels. Can you identify a subset of the habitats given in Table 1.1? Keep in mind that the maps and photos may have been produced on very different dates and therefore show differences in the landscape features. 6. Note any discharge or precipitation gauging stations in your catchment basin. These are sometimes included on topographic maps. Prepare time series plots of available data for these stations and calculate unit area precipitation and runoff. Determination of stream flow is discussed in more detail in Chapter 3, but knowing stream flow dynamics at various points in the stream network will provide a more complete view of the catchment landscape as derived in this chapter from maps and photos.

C. Advanced Method 1: Computerized Spatial Analyses of Riverscapes

While maps and photos are basic tools for understanding how your study basin fits into the regional landscape, digital approaches provide a means for examining landscapes in great detail. All points in any landscape can be precisely known from geodetic surveys. In fact, that is how the topographic maps used above were created. With the aid of a computer, topography can be reduced to a digital data base using algorithms that interpolate between surveyed points. Using software that is widely available, the computer operator can produce three-dimensional images of any digitized landscape. Topographic data can then be examined statistically or plotted in relation to any other spatial data bases (e.g., stream network, water quality, fish distribution). A number of software packages that manipulate digitized data in relation to geographic references are available under the general descriptor of geographic information systems (GIS). Considerable computer sophistication is required to use a GIS properly, although most can be run on high-speed personal computers. The advantage of a GIS is that landscape data for many variables can be created in “layers” superimposed in relation to the topography (Figure 1.3). This is a very useful way to accurately keep track of and display landscape change over time. For example, observed fish distributions within a catchment basin can be plotted in true spatial (geographic) context with the hydrography and, if time series data are available, changing fish distributions can be shown in spatial relation to changes in potentially controlling variables, such as land use activities. Hence, a GIS permits very large data sets to be systematically arrayed and related in time and space in a manner that facilitates interpretation of landscape pattern and process (Bernhardsen 2002, Longley et al. 2005). Moreover, data describing landscape patterns in some cases can be derived from spectral (reflectance) data gathered from satellite or other “remote” sensors. In this case a GIS is essential to relate massive amounts of spectral data for entire landscapes to the actual topography. Different wave lengths of light are reflected by the pattern of landscape attributes on the ground. Hence, algorithms or statistical models can be derived that relate measured spatial variation for a portion of the landscape (ground truth data) to the variation in the spectral patterns recorded remotely. The algorithms then can be used to generate landscape data layers in direct relation to the topography (Lillesand and Klefer 2000). Obviously, some landscape variables are better suited to spectral imagery than others, and considerable ground truthing is needed to verify the accuracy of the remotely sensed data. For example, water bodies are easily distinguished from terrestrial environs; coniferous forests can be distinguished from grasslands. But Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 17

Chapter 1 • Landscapes and Riverscapes 17

this technology is in a rapid state of development and should be approached with caution and a clear understanding of the research or management question. Most research universities have spatial analysis laboratories. If a GIS is not available to demonstrate utility in landscape analysis of catchment basins, I recommend that an active spatial analysis lab be toured to clearly convey the usefulness of this technology in demonstrating pattern and process at the level of entire catchment basins.

D. Advanced Method 2: Identifying Ecosystem Problems at the Landscape Scale

Now that you have summarized landscape features of your catchment basins, it is important to consider what sorts of questions or problems require resolution at a landscape scale. Almost all natural resource management questions have to be addressed to some extent in a landscape context, owing to overlapping jurisdictions. For example, in the Flathead catchment just described, nearly all federal (US) land management agencies (e.g., Forest Service, Environmental Protection Agency, Bureau of Reclamation, National Park Service) and a wide variety of state and tribal agencies have legislated authority for water resources. Without a landscape perspective, one agency could easily initiate a management objective that interferes with actions of another agency. Moreover, the ability of ecosystems to provide ecological goods and services (e.g., water, timber, wildlife, scenery) to humans clearly encompasses local to regional landscapes. But, to resolve specific problems, is it necessary to study the entire catchment? If so, how big should the catchment be? Are catchment boundaries also ecosystem boundaries? All are difficult questions. Properly scaling the research and management approach perhaps is the most difficult task faced by any ecologist. However, thorough synthesis of available information about the particular problem in a landscape context is the place to start. In the case of the Flathead Lake bull charr, the entire catchment of the Flathead River clearly is the ecosystem that sustains this fish. In this case the catchment boundaries are the ecosystem boundaries in this very large and complex landscape. For salmon the ecosystem boundaries are much larger, extending beyond the river catchment well into the ocean. Determining the causes and consequences of the bull charr and salmon declines and implementation of a solution to sustain fisheries over the long term must involve an understanding of the habitat requirements of the various life history stages of the fish as well as a predictive understanding of the complex biophysical processes that control the quantity and quality of those habitats. River ecosystems encompass ecological, social, and economic processes (ecosystem functions) that interconnect organisms (ecosystem structure), including humans, over some time period. The ecosystem boundaries are permeable with respect to energy and materials flux; therefore, even large systems are influenced by external events such as global climate change, pollution, national and global economies, and emigration of people and nonnative biota. This holistic view should be kept in mind as approaches to resolution of river ecological questions are considered.

1. Using the salmon example as a general guide, list a series of river ecological questions that may be inferred from the landscape attributes of your catchment basins. For example, if your catchment is dominated by agricultural lands, what sorts of river problems might you expect? 2. Determine where in your catchment basin you would place monitoring or study sites to assemble river ecological information to solve your list of problems. Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 18

18 Stanford

IV. QUESTIONS A. Boundaries and Hydrography of the Catchment Basin

1. Based on your measures of the stream network, does it appear that your catchment basin is very dry or very wet? 2. How does “wetness” of the catchment basin relate to the density of the stream network? 3. Is the stream network “fragmented” in any way by natural obstructions, such as landslides, lakes, wetlands, beaver dams, or interstitial flow pathways, or is the stream profile a continuous surface flowpath? 4. Are alluvial floodplains a dominant feature of the stream corridor? 5. Is the floodplain habitat catena intact? 6. Is discharge from the catchment likely to be significantly controlled by reservoir storage and/or dam operations?

B. Other Landscape Attributes of the Catchment Basin

1. Is the bedrock substrata of your catchment basin likely to be very porous or will most of the precipitation run off via surficial channels? 2. Is the water chemistry of the river system likely to be well buffered or poorly buffered? 3. Is your catchment basin human dominated? 4. What manmade structures are present in the catchment basin that might change flow and channel form or obstruct migrations of biota? 5. What stream channels appear to have a closed canopy as a consequence of dense riparian forest and how might canopy cover influence ecological processes in the stream? 6. What is the predominate vegetation type in the catchment basin and how might it influence river ecology? 7. What is the predominate human land-use activity in the catchment basin and how will that activity likely affect river ecology?

C. Computerized Spatial Analyses of Landscapes

1. What sorts of problems in river ecology do not require use of a computerized GIS system? 2. What problems in river ecology might usefully be analyzed by a computerized GIS in your catchment? 3. How can a GIS be used to document landscape changes in your catchment basin?

D. Identifying Ecosystem Problems at the Landscape Scale

1. Have you included all landscape units in your catchment basin that may exert significant ecological influences on the river system? 2. Can you observe fragmentation in geohydraulic continuum caused by human activities and, if so, how do they relate to your list of research and management problems? Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 19

Chapter 1 • Landscapes and Riverscapes 19

3. Are your catchment boundaries also ecosystem boundaries with respect to your list of river ecological problems? 4. Based on the information about bull charr and the landscape attributes of the Flathead catchment described, answer the following questions: a. What processes likely are influencing the distribution and abundance of bull charr in the Flathead River-Lake catchment? b. State these likely processes in the form of hypotheses about the decline of Flathead Lake bull charr. c. What landscape information is needed to test these hypotheses? d. What other ecological information and data are needed to better understand the bull charr problem and in what time frame should these data be collected?

V. MATERIALS AND SUPPLIES

Aerial photo series, preferably stereo pairs, and/or multispectral digital image data Geologic maps GIS demonstration Groundwater maps Map measurement wheels Planimeters or digitizing pads and computers Plastic overlays and color markers Stereoscopes for photo interpretation Topographic maps of the study region at various scales Vegetation maps

VI. REFERENCES

Andrewartha, H. G., and L. C. Birch. 1954. The distribution and abundance of animals. University of Chicago Press, Chicago, IL. Bernhardsen, T. 2002. Geographic Information Systems, An Introduction, 3rd ed. John Wiley and Sons, Toronto, Canada. Colinvaux, P. A., M. C. Miller, K. Liu, M. Steinitz-Kannan, and I. Frost. 1985. Discovery of permanent Amazon lakes and hydraulic disturbance in the upper Amazon Basin. Nature 313:42–45. Day, J. A., and B. R. Davies. 1986. The Amazon River system. Pages 289–318 in B. R. Davies and K. F. Walker (Eds.) The Ecology of River Systems. Dr. W. Junk Publishers, Dordrecht, The Netherlands. Dynesius, M., and C. Nilsson. 1994. Fragmentation and flow regulation of river systems in the northern third of the world. Science 266:753–762. Fausch, K. D., C. E. Torgersen, C. V. Baxter, and H. W. Li. 2002. Landscapes to riverscapes: Bridging the gap between research and conservation of stream fishes. BioScience 52:483–498. Gibert, J., J. A. Stanford, M. J. Dole-Olivier, and J. V. Ward. 1994. Basic attributes of groundwater ecosystems and prospects for research. Pages 7–40 in J. Gibert, D. L. Danielopol, and J. A. Stanford (Eds.) Groundwater Ecology. Academic Press, San Diego, CA. Hauer, F. R., C. N. Dahm, G. A. Lamberti and J. A. Stanford. 2003. Landscapes and ecological variability of rivers in North America: factors affecting restoration strategies. Pages 81–105 in R. C. Wissmar and Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 20

20 Stanford

P. A. Bisson (Eds.) Strategies for Restoring River Ecosystems: Sources of Variability and Uncertainty in Natural and Managed Systems. American Fisheries Society. Bethesda, MD. Hauer, F. R. and M.S. Lorang. 2004. River regulation, decline of ecological resources, and potential for restoration in a semi-arid lands river in the western USA. Aquatic Sciences 66:388–401. Hynes, H. B. N. 1975. The stream and its valley. Verhandlungen der Internationalen Vereinigung für Theorestische und Angewandte Limnologie 19:1–15. Junk, W. J. 2005. Flood pulsing and the linkages between terrestrial, aquatic, and wetland systems. Verhandlungen der Internationalen Vereinigung für Theorestische und Angewandte Limnologie 29:11–38. Junk, W. J., J. J. Ohly, M. T. F. Piedade, and M. G. M. Soares, (Eds.). 2000. The Central Amazon Floodplain: Actual Use and Options for a Sustainable Management. Backhuys Publishers, Leiden, The Netherlands. Leopold, L. B., M. G. Wolman and J. P. Miller. 1964. Fluvial processes in geomorphology. W. H. Freeman and Co., San Francisco, CA. Lillesand, T. M., and R. W. Klefer. 2000. Remote Sensing and Image Interpretation, 4th ed. John Wiley and Sons, London, UK. Longley, P. A., M. F. Goodchild, D. J. Maguire, and D. W. Rhind. 2005. Geographic Information Systems and Science, 2nd ed. John Wiley and Sons, Toronto, Canada. Lowe-McConnell, R. H. 1987. Ecological studies in tropical fish communities. Cambridge University Press, Cambridge, UK. Mangin, A. 1994. Karst hydrogeology. Pages 43–67 in J. Gibert, D. L. Danielopol, and J. A. Stanford (Eds.) Groundwater Ecology. Academic Press, San Diego, CA. Mertes, L. A. K. 1997. Documentation of the significance of the perirheic zone on inundated floodplains. Water Resources Research 33:1749–1762. Nilsson, C., C. A. Reidy, M. Dynesius and C. Revenga. 2005. Fragmentation and flow regulation of the world’s large river systems. Science 308:405–408. Petrere, M., Jr. 1991. Life strategies of some long-distance migratory catfish in relation to hydroelectric dams in the Amazon Basin. Biological Conservation 55:339–345. Petts, G. E. 1984. Impounded Rivers: Perspectives for Ecological Management. John Wiley and Sons, Chichester, UK. Poff, N. L., J. D. Allan, M. B. Bain, J. R. Karr, K. L. Prestegaard, B. D. Richter, R. E. Sparks, and J. C. Stromberg. 1997. The natural flow regime: A paradigm for river conservation and restoration. BioScience 47:769–784. Poole, G. C. 2002. Fluvial landscape ecology: Addressing uniqueness within the river discontinuum. Freshwater Biology 47:641–660. Salo, J., R. Kalliola, I. Häkkinen, Y. Mäkinen, P. Niemelä, M. Puhakka, and P. D. Coley. 1986. River dynamics and the diversity of Amazon lowland forest. Nature 322:254–258. Schumm, S. A., and R. W. Lichty. 1956. Time, space and causality in geomorphology. American Journal of Science 263:110–119. Schumm, S. A., M. P. Mosley, and W. E. Weaver. 1987. Experimental Fluvial Geomorphology. Wiley Interscience, New York, NY. Stanford, J. A., and B. K. Ellis. 2002. Natural and cultural influences on ecosystem processes in the Flathead River Basin (Montana, British Columbia). Pages 269–284 in J. S. Baron, editor. Rocky Mountain Futures: An Ecological Perspective. Island Press, Washington, DC. Stanford, J. A., and F. R. Hauer. 1992. Mitigating the impacts of stream and lake regulation in the Flathead River catchment, Montana, USA: an ecosystem perspective. Aquatic Conservation: Marine and Freshwater Ecosystems 2:35–63. Stanford, J. A., F. R. Hauer, S. V. Gregory, and E. B. Snyder. 2005a. The Columbia River. Pages 591–653 in A. C. Benke and C. E. Cushing (Eds.) Rivers of North America. Elsevier/Academic Press, Boston, MA. Stanford, J. A., M. S. Lorang, and F. R. Hauer. 2005b. The shifting habitat mosaic of river ecosystems. Verhandlungen der Internationalen Vereinigung für Theoretische und Angewandte Limnologie 29:123–136. Stanford, J. A., and J. V. Ward. 1992. Management of aquatic resources in large catchments: Recognizing interactions between ecosystem connectivity and environmental disturbance. Pages 91–124 in R. J. Naiman (Ed.). Watershed management. Springer-Verlag, New York, NY. Stanford, J. A., J. V. Ward, W. J. Liss, C. A. Frissell, R. N. Williams, J. A. Lichatowich, and C. C. Coutant. 1996. A general protocol for restoration of regulated rivers. Regulated Rivers: Research and Management 12:391–413. Elsevier US 0mse01 29-3-2006 2:08p.m. Page No: 21

Chapter 1 • Landscapes and Riverscapes 21

Strahler, A. N. 1963. The Earth Sciences. Harper & Row, New York, NY. Ward, J. V. 1989. The four-dimensional nature of lotic ecosystems. Journal of the North American Benthological Society 8:2–8. Wetzel, R. G. 2001. Limnology: Lake and River Ecosystems, 3rd edition. Academic Press, San Diego, CA. Williams, R., (Ed.). 2006. Return to the River: Restoring Salmon Back to the Columbia River. Elsevier Academic Press, Amsterdam, The Netherlands.