Managing riparian for services and

A handbook for the cotton industry Contents

Introduction 1

Part 1. Understanding riparian ecosystems 2 What are riparian ecosystems? 3 Riparian ecosystem functions 5 Riparian ecosystem services 9 Factors influencing riparian ecosystems 11 Threats to riparian ecosystems 12

Part 2. Managing riparian ecosystems 15 Management goals and priorities 16 Protecting and restoring riparian ecosystems 20 How to maintain & rebuild a riparian buffer 23 Monitoring & evaluation 28 Introduction

Riparian ecosystems are highly valuable Modified and degraded riparian vegetation is This handbook provides an overview of riparian components of the . They support a associated with many environmental problems ecosystems and their management in relation to diverse range of critical ecological functions, including bank erosion, quality deterioration cotton farms in inland semi-arid lowland regions harbour high levels of biodiversity and provide and biodiversity loss. Effective management of of eastern . The first part synthesises many important ecosystem services to people. riparian ecosystems is therefore vital in semi-arid current understanding of riparian ecosystems, their agricultural to conserve biodiversity, functions and ecosystem services and the main Riparian ecosystems are particularly important maintain ecological functions, promote ecosystem factors influencing these. Major threats to riparian in settings where there is a distinctive difference services and limit environmental degradation. The ecosystems in cotton growing regions are also between riparian vegetation and vegetation of value of riparian ecosystems can also be expected considered. the surrounding landscape. This is generally the to grow as the changes (Capon et al. 2013). case in semi-arid and arid regions where riparian The second part of the handbook provides vegetation tends to be the most diverse and information concerning management of riparian complex vegetation in the landscape. Additionally, Purpose of this handbook ecosystems including setting management goals riparian vegetation often comprises the most and priorities as well as approaches to protecting significant remnant (and regrowth) vegetation in A significant proportion of cotton farms in and restoring riparian ecosystems. Guidelines for agricultural landscapes. Australia are situated in lowland, floodplain areas monitoring and evaluation of riparian ecosystem of semi-arid inland catchments, especially in the management are also included. In rural settings, riparian zones are multifunctional northern Murray-Darling Basin straddling the that support many human activities (e.g. Queensland and New South Wales border. Riparian cropping, grazing, water supply, recreation etc.) ecosystems comprise large areas of most cotton in addition to crucial ecological functions. As properties in these regions as well as representing well as providing significant for terrestrial substantial proportions of remnant vegetation biodiversity, riparian ecosystems play a major in these landscapes. Consequently, protecting role in determining river health by providing an and effectively managing riparian ecosytems for important buffer that protects aquatic ecosystems ecosystem services and biodiversity are important from disturbances and from human objectives contributing to the sustainability of the activities in the surrounding landscape. Australian cotton industry.

Vegetation condition is typically the single most important factor determining the ecological function and value of riparian ecosystems. 1 Part 1. Understanding riparian ecosystems What are riparian ecosystems?

Riparian zones are most simply defined as areas A functional definition of riparian of land adjacent to watercourses or waterbodies ecosystems (Naiman et al. 2008). Consequently, riparian zones can be viewed as interfaces, transition A can also be defined from a zones or ‘ecotones’ between neighbouring functional perspective as an area of land that terrestrial and aquatic ecosystems (Naiman et al. adjoins and directly influences, and is directly 1998). influenced by, a body of water, even if this only flows occasionally (Price & Tubman 2007). Because of their position in the landscape, Riparian ecosystems are therefore those which riparian ecosystems are characterised by both exert a direct influence on adjacent gradients in environmental conditions (e.g. watercourses or waterbodies and are themselves elevation or flooding). These environmental influenced by the hydrology and geomorphology gradients tend to be reflected by ‘zonation’ of these aquatic systems. in ecological processes and the occurrence of . More aquatic and amphibious Consequently, riparian ecosystems can include: , for instance, generally occur in the • river banks lower, wetter parts of riparian zones with more • dry river beds and creeks terrestrial species occurring as you move further • dry lake beds away from the waterbody. • floodplains • floodplain In the semi-arid lowland regions of the Murray-Darling Basin, common riparian vegetation zones often include river red gums on the immediate river banks which grade into coolibahs at higher elevations. Low-lying Common riparian ecosystems swampy riparian areas in the region often of cotton farms in the northern support lignum shrubland. Murray-Darling Basin dominated by river red gum (top), coolibah (middle) and shrubs including tangled lignum and Eremophila species (bottom). 3

Riparian ecosystem functions

Riparian ecosystems support many critical for aquatic fauna that are sensitive to high water 3. trapping ecological functions (Figure 1) which fall broadly temperatures (Stewart et al. 2015). Where most Riparian vegetation plays an important role into seven major categories (Capon and Pettit riparian vegetation has been removed from stream trapping from the catchment and 2018): banks, water temperatures can exceed the lethal reducing sediment inputs entering watercourses limits of many aquatic organisms which, without and waterbodies. This is particularly critical in 1. Microclimatic regulation , have no areas of lower water temperature headwater streams which can drain around 70 % of to escape to during hotter parts of the day. Even growing on the edge of watercourses, the catchment and are a major source of sediment. partial shading created by riparian vegetation especially trees and shrubs, shade aquatic Sediment loads and nitrate concentrations in can create refuges of lower water temperature for ecosystems, reducing in-stream light and water a river in the United States, for example, were aquatic fauna in the summer. temperatures (Bayley & Williams 1981; Bunn 1993, reduced by up to 90 % in water flowing through Davies et al. 2008). Shading by riparian plants is naturally vegetated riparian headwater areas particularly important for limiting algal growth in 2. Nutrient filtration and cycling (Gilliam 1994). streams, especially where there are high nutrient Riparian vegetation can limit the amount of In lower reaches of a catchment, riparian inputs from surface and flows nutrients entering streams via surface and vegetation within and fringing the stream channel (Peterjohn & Correll 1984; Chauvet & Decamps groundwater flows (Peterjohn and Correll 1984, can reduce stream flow and allow deposition of 1989). Where riparian vegetation has been Weaver & Reed 1998) as the riparian interface is sediments. This natural process is important for disturbed, increased light and water temperature, where most surface and shallow subsurface flows the maintenance of channel landforms as well as along with elevated nutrients, can stimulate of water enter the stream. Biological processes, riparian vegetation condition by providing areas excessive algal growth, reducing oxgygen levels and including nutrient uptake by plants and microbial for regeneration of riparian plants (Nanson & altering in streams with detrimental effects processes (e.g. denitrification), influence the Beach 1977). on other aquatic organisms. As growth of most retention of nutrients in the riparian zone and aquatic plants, including green , is controlled reduce nutrient concentrations entering waterways. by light availability more than nutrient levels, Riparian vegetation also provides a source of wood that can accumulate within channels and riparian shading can be a major driver of aquatic Riparian ecosystems can also absorb nutrients from on floodplains, further reducing flow rates and primary productivity (Davies et al. 2008). At sites the stream as water continually exchanges between promoting deposition of sediments (Abbe et al. with high nutrient levels, shading can therefore the streambed and bank sediments. Phosphorus 2003). This is particularly important in channels ameliorate the effects of nutrient enrichment and can be adsorbed to sediment particle surfaces with sandy beds that lack other hard surfaces, such restrict and algal growth. and nitrogen can be utilised or transformed via as rocks and boulders, to reduce the mobilisation microbial activities. Riparian canopy cover can also influence in-stream and increase the entrapment of sediments (Beesley water temperatures. This is particularly important 1996). 5 4. Landform stabilisation Vegetation is particularly important for stabilising Rivers are naturally high-energy systems, landforms when rivers are in . During especially in periods of high flows and , and flooding, riparian vegetation reduces the velocity consequently some erosion is a natural occurrence. and spread of floodwaters and reduces bank Without riparian vegetation, however, increased wetness via evapotranspiration, (Pen 1999). River erosion of bank and stream bed sediments can lead bends are major sites of erosion and deposition as to the transport of more sediment downstream, material is eroded from the outside of the bend reducing and potentially burying and deposited on the inside. In many rivers, these important aquatic habitats. Stream banks with little depositional areas (i.e. point bars) provide a major or degraded vegetation can also become unstable substrate on which primary succession of riparian with erosion during high flow events leading to vegetation communities can take place (Malanson greater flooding of surrounding land (Thorne 1993). 1990) and widening, shallowing and simplication of stream channels. 5. Food-web subsidies Significant flows of energy and materials occur Riparian vegetation can limit channel erosion and between riparian zones and adjacent aquatic down-cutting by reducing the force of flowing ecosystems (Polis et al. 1997). Organic matter water, protecting banks from its direct impacts inputs (e.g. leaf litter) are crucial to aquatic and by inducing sediment desposition (Malanson foodwebs. The and diversity of aquatic 1993). Without perennial vegetation, subsidence macroinvertebrates, for example, tend to be greatly of banks can occur, particularly if the is wet reduced when streams are deprived of leaf litter and the bank can collapse under its own weight Riparian trees and fallen timber play an important role inputs (Davies 1994; Wallace et al.1997). Riparian (Thorne 1990). in stabilising river banks. ecosystems also contribute many organisms to aquatic foodwebs (Nakano & Bank stability is maintained by the roots of Murakami 2001). Terrestrial can perennial vegetation, especially trees and provide up to half the annual energy budget for shrubs, which provide a stable base for binding , especially in closed-canopy riparian zones the soil and holding the bank in place (Pen (Baxter et al. 2005). 1999). Accumulation of sediments promotes establishment of riparian vegetation that, in turn, Many Australian riparian trees are from the reduces near-bank flow velocities and tractive Myrtaceae family (e.g. Eucalyptus, Melaleuca) forces, reducing erosion and increasing deposition and have tough leaves that are high in tannins of sediment (Thorne 1990). Large tree roots anchor and volatile oils and are not readily broken down river banks while roots and rhizomes of perennial in the stream. Tannins contained in these leaves understorey vegetation (e.g. shrubs and sedges) can stain the water, reducing penetration of light hold surface soil in place between these larger and limiting , further limiting roots. algal growth in streams with elevated nutrients. 6 6. Aquatic habitat 7. Terrestrial habitat Riparian vegetation plays an important role in The diversity and dynamics of riparian vegetation Gwydir case study generating a diversity of habitats for in-stream contribute to higher species diversity and Of 90 species observed during terrestrial organisms which can have an important influence abundance of plants in riparian ecosystems as well on the maintenance of aquatic biodiversity. in the surrounding catchment. Riparian zones are vertebrate fauna studies on cotton farms in the generally considered hotspots of diversity as they Gwydir River catchment, 26 species were only Overhanging roots and branches from riparian form a transition zone between the different plant observed in riparian (i.e. channel bank) habitats plants introduce physical habitat structure to communities of terrestrial and aquatic systems including peaceful dove (Geopelia placida), channels. Leaf litter and fallen branches from (Wissmar & Swanson 1990; Nilsson et al. 1993; riparian vegetation provide substrates and habitat Naiman & Decamps 1997). white-plumed honeyeater (Ptilotula penicillata), for aquatic organisms while fallen trees can create little friarbird (Philemon citreogularis), willie ‘riffle’ zones and step-pools (Malanson 1993). As Intact riparian vegetation often comprises a range wagtail (Rhipidura leucophrys) and inland well as influencing flows and channel morphology, of taxonomic groups of plants of various life forms large woody debris also affects the colonisation and functions. Riparian plants typically display a freetail bat (Mormopterus species 3). and establishment of many riparian plant species variety of that enable them to persist in in river channels and on floodplains, further an environment with a high frequency of natural promoting in-stream habitat diversity (Naiman et disturbances (e.g. flooding and ). This al. 1998; Pen 1999, Lovett & Price 1999). provides riparian vegetation with a relatively high degree of resilience to other disturbances in the river environment.

Riparian vegetation also offers many different habitats for terrestrial fauna, especially that prefer the moist, productive riparian habitat to adjacent upland areas (Leach & Edge 1994). Riparian zones can provide terrestrial ‘corridors’ that connect remnant patches of vegetation (Watson 1991) in modified catchments, allowing Peaceful dove (Geopelia placida) animals and plants to disperse throughout the landscape (Knopf & Samson 1994). The great Additionally, the number of bird species diversity of habitat formed by these corridors of natural riparian vegetation makes them very recorded in riparian habitats was nearly twice important for regional biodiversity (Naiman et al. that recorded in floodplain habitats. Similarly, 1993). Species diversity and abundance of birds the number of bat species was about 30 % lower and mammals is often greater in riparian corridors in floodplain habitats compared with riparian Overhanging branches and roots, as well as fallen leaves than in the surrounding landscape (Decamps et al. and wood provide aquatic habitat. 1987; Crome et al. 1994). (channel bank) habitats. 7 Figure 1. Major ecological functions supported by riparian ecosystems and their effects on terrestrial and aquatic ecosystems.

8 Riparian ecosystem services In addition to supporting healthy and resilient All of these ecosystem services are supported aquatic and terrestrial ecosystems, riparian by riparian ecosystem functions either directly, ecosystem functions provide many benefits to as in the case of water filtration and shading, Riparian ecosystems can be sites of cultural and people (Table 1). These ‘ecosystem services’ fall or more indirectly as in the case of natural social signficance. Balonne River near St George, into three broad types: pest control. For natural pest control, the most 1917 (top), and Brewarrina fish traps, Barwon important feature is simply cover of native River (bottom). 1. production services, i.e. provision of plants, particularly in the understorey (Cate goods such as pasture, timber, food, fibre Paull (CSIRO) pers. comm.). Insectivorous birds etc. sheltering and nesting in riparian vegetation, for 2. regulating and supporting services, example, can play a significant role controlling i.e. services that regulate and support of that are potentially healthy ecosystem function such as water harmful to agriculture, horticulture, native plants filtration, nutrient cycling, micro-climate or people (Loyn 1987). regulation; and Recent work suggests that riparian ecosystems 3. cultural services, e.g. recreation and on Australian cotton farms also have significant historical, social, spiritual values. carbon sequestration potential (Smith and Reid 2013; Smith et al. 2017). Old growth river red Reid et al. (2003) identified major ecosystem gum forests in particular can store substantial services provided by natural areas on Australian amounts of carbon (Rhiannon Smith (UNE) cotton farms: pers. comm.). The sequestering of carbon by 1. natural pest control, trees is important for reducing carbon dioxide 2. maintenance of soil health, in the atmosphere that would otherwise be 3. water filtration, contributing to warming of the Earth. 4. prevention of soil erosion, 5. water absorption and breakdown, Riparian ecosystems also provide many cultural 6. maintenance of river flows, and social benefits as sites of significance for 7. maintenance of groundwater levels and cultural heritage, recreation and tourism, science groundwater quality, and education, and aesthetic and spiritual values. 8. maintenance and regeneration of habitat, 9. maintenance and provision of genetic , 10. regulation of climate, and provision of shade, shelter and barrier effect. 9 Table 1. Major ecological functions and related ecosystem services of riparian ecosystems and their key drivers.

Key drivers

Ecological functions Key ecosystem services Vegetation traits Other factors Light and temperature control Shading, drought Canopy cover, canopy height Channel width, channel orientation, ground-water influence, instream nutrient levels

Nutrient filtration Water quality regulation Buffer width, continuity, groundcover, Topography (slope), hydrology (depth to leaf litter density, composition, below- , water residence , ground/ ground microbial interactions, rooting soil water interactions), soil type depth

Sediment trapping Water quality regulation Buffer width, continuity, stem density, Topography (slope), soil moisture (depth root structure (density and depth to water table), soil type, hydrology, profile), community composition of hydraulics, diversity of other substrates different functional groups (i.e. trees, shrubs and herbs) Bank/bed stabilisation Water quality regulation, land stability

Food-web subsidies Biodiversity Composition (e.g. leaf traits), temporal Flooding, water quality, nutrients dynamics

Aquatic habitat Biodiversity, fish Composition, temporal dynamics, Hydrology, hydraulics, water quality, spatial heterogeneity nutrients Terrestrial habitat Natural pest control, pasture, timber, Canopy cover, composition, temporal Hydrology, other disturbances (e.g. biodiversity, mitigation, dynamics, floral diversity, buffer width, grazing, fire), regional climate, erosion control longitudinal connectivity surrounding land cover

Carbon storage and sequestration Abundance of mature trees, tree Soil type recruitment and regrowth

Cultural values; recreation & tourism; Composition and structure science & education; aesthetic, spiritual & wilderness values 10 Factors influencing riparian ecosystems

The capacity of riparian ecosystems to provide with riparian vegetation, can provide an effective Other ecosystem services of particular benefit to ecosystem services is determined mainly by the nitrate buffering capacity with a 30-50 metre farmers are governed by relatively straightforward structure and composition of riparian vegetation wide buffer reported as being sufficient to remove drivers. Natural pest control on cotton farms, for (Table 1). Important characteristics of riparian all nitrates seeping through in the groundwater example, appears to be promoted mainly by an vegetation encompass its composition (i.e. number (Pinay & Decamps 1988; Pinay et al. 1993). These abundance of native flowering plants (pers comm. and type of species) and structure (e.g. canopy processes are most effective if the gradient of Cate Paull, CSIRO). Similarly, carbon storage in height, canopy cover, root depth and density, riparian land is low enough (<5%), and the distance riparian landscapes of Australia’s semi-arid cotton groundcover including leaf litter and wood cover). through the riparian land is long enough (>50m), growing regions is strongly associated with the to allow sufficient time for the chemical reactions abundance of mature trees, especially river red gum The effectiveness of riparian vegetation in to take place. (pers comm. Rhiannon Smith, University of New supporting ecosystem services can also be modified England). Riparian vegetation also aids in reducing by many other factors such as topography, soil/ The capacity of riparian ecosystems to regulate bank erosion and mitigating salinisation of soil sediment characteristics, climate and hydrology water quality by trapping sediments is also (pers comm. Rhiannon Smith, University of New and surrounding land use (Table 1). The amount influenced by a combination of vegetation England). and impact of shade created by riparian vegetation, structure, soil type and topography (Table 1). for example, is influenced by several factors, Dense vegetation cover; deep, organic, permeable At a landscape scale, the spatial characteristics of including canopy height and foliage density as well and low gradients combine to form a buffer riparian vegetation will also influence its capacity as channel width and orientation (Bunn et al. 2007; which moderates the delivery of sediment to to provide ecosytem services, including its width, Davies et al. 2008). streams. longitudinal continuity along watercourses and lateral connectivity with upland ecosystems. The capacity of riparian ecosystems to retain nutrients, and thereby regulate water quality, is controlled by hydrologic characteristics such Case Study: Shade & leaf litter determine plant establishment from soil seed banks as water table depth, water residence time and Experiments were conducted using soils collected from riparian zones across the northern Murray- groundwater interactions with soil water. The Darling Basin to investigate understorey vegetation responses to a range of leaf litter, shading and relative influence of biological nutrient cycling hydrological treatments. Shade increased the abundance, and reproduction of processes will depend on water (and nutrient) germinating plant communities under dry, but not wet, conditions. In contrast, leaf litter reduced input rates, soil characteristics and vegetation type. the establishment and growth of understorey plants under dry and wet conditions. The results emphasise the importance of the riparian canopy in shaping understorey vegetation responses Riparian vegetation is generally considered to be to wetting or drying. In particular, the findings suggest that leaf litter is likely to supress the establishment and reproduction of weeds residing in the soil seed banks of these riparian zones. a good short-term filter for removing N, P, Ca and Mg from runoff flowing from upland areas (Source: Capon et al., 2017) (Lowrance et al. 1984). Wet riparian soils, together 11 Threats to riparian ecosystems

Riparian ecosystems face many threats in modified Clearing of land adjacent to the riparian zone can Channelisation and levees landscapes, especially in relation to land use also result in rising watertables, causing stress and Clearing within riparian and catchment areas and land cover change in catchments as well as even of the vegetation through permanent affects infiltration and transport of water through alteration to hydrological regimes. waterlogging and/or salinity (Peck 1978; Busch the catchment and can lead to significant flooding, & Smith 1993). Loss of mature trees particularly particularly in low reaches of streams. Increased Changes to riparian ecosystems in rural landscapes from riparian zones will lead to a decline in shade frequency and magnitude of peak flows can also are generally related to the loss of riparian and leaf litter available in the system. Shade has occur, resulting in erosion of stream banks and vegetation and an increase in weed invasion. been shown to be particularly important for beds. Bank erosion, in particular, will lead to Flow-on effects to native wildlife (e.g. birds) are estabalishing seedlings in dry areas (Capon et al. channel widening and deepening, which can cause typical and can have cascading effects on ecosystem 2017). Leaf litter often benefits understorey plants fringing riparian vegetation to collapse into the function and resilience by affecting their role in in arid areas by providing a microclimate that river, reducing the width of the riparian buffer. pollination, seed dispersal and insectivory. protects against desiccation (Capon et al. 2017). A Such flooding also has the potential to destroy reduction in leaf litter has the potential to inhibit riparian plant communities, with altered conditions Some of the more immediate and serious threats the growth of understorey vegetation. affecting their ability to naturally regenerate. to riparian ecosystems in agricultural landscapes include: High nutrient levels In some situations, past management solutions Surface water flows from rural catchments can to mitigate flooding have included engineering Vegetation clearing and change carry nutrients into the riparian zone, particularly approaches, such as channelization of the stream Fragmentation of riparian vegetation isolates where this land has been fertilised or carries network, to improve the conveyance of high flows, remnant patches, leading to the loss of continuity livestock (Lowrance et al. 1984; Weaver & Reed and the building of levees to reduce overbank flow. along watercourses and connectivity within the 1998). Such solutions can, themselves, however lead to riparian zone and between the riparian zone and bigger problems for the stream and riparian area. upland areas. Both continuity and connectivity are Elevated inputs of nitrates may result in Channelisation will simplify both the structural essential for ecological processes and the resilience eutrophication (i.e. excessive nutrients leading (i.e. removal of woody debris) and hydraulic (i.e. of the broader stream network and their loss can to dense algae/plant growth) and acidification loss of riffles, pools and backwaters) diversity that lead to the general degradation of the riparian of waterways, impacting on in-stream supports ecological processes and biodiversity. The vegetation. With less available foliage for native macroinvertebrates and other fauna (Jeffries & construction of levees will disconnect the river grazers like wallabies, remaining vegetation is at Mills 1990). from its floodplain and reduce flood frequency greater risk of overgrazing. leading to the degradation of riparian vegetation communities.

12 Introduced weed species Loss of native plants, and a high edge to area ratio of riparian zones makes them particularly vulnerable to invasion by exotic plants. Weed infestations are often the result of disturbance or the build-up of excessive nutrients caused by increased run-off. Invasive plants can increase competition for and resources amongst native species and may result in further loss of local plant diversity.

Many exotic plants have soft leaves that break down quickly, adding nutrient and labile carbon to waterways, that can drastically alter in-stream (Pidgeon & Cairns 1981; Pen 1999). These soft-leaved exotic plants can therefore supply a ready source of carbon which, in combination with high nutrient levels, can lead to rapid growth of in- stream algae with the potential to cause detrimental algal blooms.

Leaf fall into streams from exotic plants is also likely to affect aquatic food webs as organisms in most Australian streams are adapted to Myrtaceous leaves (i.e. from Eucalyptus and Melaleuca species) which are high in tannins and other volatile chemicals so that they breakdown very slowly. Because of these chracteristics of native riparian tree leaves, leaf shredding macroinvertebrates are not common in Australian streams.

Exotic perennial grasses can also dominate riparian areas, reducing light and trapping sediment, reducing the channel competence to convey high water flows (Bunn et al. 2003), leading to increased potential for flooding of surrounding areas. 13 Removal of large woody debris Altered fire regimes Logs are often removed from watercourses to Fires in riparian zones are the result of interactions reduce the risk of flooding or to improve ease between fire characteristics and the biophysical of transportation. However, large woody debris characteristics of the riparian environment (Pettit (LWD) provides many functions to the stream and & Naiman 2007). Altered fire regimes within riparian zone and its importance is well known riparian zones can have a detrimental affect on (Gregory et al. 1991, Abbe et al. 2003). LWD regeneration of vegetation. provides habitat to both aquatic and terrestrial organisms, alters stream flow and geomorphology Riparian zones can also act as a buffer against fire and re-enforces stream banks to protect against and therefore as a refuge for fire-sensitive species. erosion. However, under some circumstances, such as dry climatic conditions and the accumulation Accumulation of woody debris in large rivers of dry fuel, riparian areas become corridors for increases channel complexity and initiates riparian fire movement. In areas of native vegetation, succession on alluvial surfaces (Gregory et al. wildfires would probably have occurred historically 1991; Fetherston et al. 1995; Abbe & Montgomery from time to time and, as for upland vegetation, 1996; Naiman et al. 2002; Gurnell et al. 2005). many plants in the riparian zone may require a Wood within the active river channel promotes the disturbance such as fire for recruitment (Kellman formation of bars, pools and side channels, and & Tackaberry 1993) and to stimulate seed release provides a moist, nutrient-rich microenvironment (Lamont et al. 1991). for macroinvertebrates, and plant propagules (McBride & Strahan 1984; Jacobsen et al., 1999). Secondary effects of riparian fire include altering nutrient fluxes and cycling, increasing sediment The removal and destruction of riparian trees will loads, and stimulating erosion. Some plants, e.g. also lead to the eventual loss of LWD as there are sedges and rushes at the outer edge of the riparian no old and dead trees and branches replacing the buffer, can provide a natural firebreak and reduce natural attrition of LWD. Fires in the riparian zone the risk of riparian fires spreading to agricultural are also a major source of loss of LWD (Pettit & areas and vice versa. Naiman 2007).

Large woody debris in the Lachlan River at Booligal, NSW. 14 Part 2. Managing riparian ecosystems

15 Management goals & priorities Management goals and priorities for riparian zones sediments and nutrients and biogeochemical appropriate leaf litter levels to provide a beneficial should be designed to promote particular attributes processes such as denitrification (Hairsine 1996). microclimate for new understorey growth. In that are important for the maintenance and addition, replanting or re-seeding of native resilience of riparian ecosystem functions (Table 2). Woody debris is a critical element for the plants can enhance and thicken natural riparian maintenance of ecosystem function with its vegetation. This usually requires some site Replanting riparian vegetation can be effective complex structure (e.g. leaves, branches, trunk and preparation such as soil amendment or weed and for providing shade and maintaining channel roots) providing a number of different-sized spaces, pest control. Where riparian areas are severely attributes, however, the desired effects of replanting including hollows, representing important habitat degraded, major site preparation may be required will be sensitive to channel width, tree height and both instream and in the riparian zone (Pettit et and may include earthworks to stabilize stream stream orientation. Even on broad streams where al.2012). Many freshwater fish species rely on banks, weed and pest control, revegetation and trees cannot shade most of the stream, riparian stable woody debris, as well tree roots and aquatic protection from disturbance (e.g. fencing). trees will provide some areas of shade for aquatic vegetation, as their nurseries. Woody debris also animals in stream areas very near the bank (Davies plays an important role in bank stabilization (Abbe Whilst planting additional aquatic vegetation is et al. 2008). Most shading by riparian vegetation et al. 2003). not always possible or suitable, by concentrating occurs on north-south orientated streams. For east- on the other management strategies listed here, west flowing streams in Australia, planting on the The goal of implementing on-ground management and maintaining a low density of invasive species, north bank of channels should be prioritised for efforts to protect and restore the riparian area is native aquatic plants will be given the best chance maximum shade effect (Bunn et al. 1999, Davies et to maintain or return this to a good condition so to thrive. This in turn enhances the nursery al. 2007). that that it can provide the required functions and habitat for freshwater and estuarine fish, in turn associated ecosystem services (Table 1). This can be supporting much of the trophic system. For bank stabilization, the effect of riparian trees achieved by determining the riparian functions that depends upon the size of the tree and the size of are most important at a given site (either naturally, When prioritizing riparian areas to maintain the channel bank. Planting trees low on a stream or otherwise) and understanding which riparian or rehabilitate it is usually easiest and most cost bank will increase bank resistance to slumping and functions are most under threat. The potential effective to work on the least damaged areas first provide the most shade. to repair the function (i.e. likelihood of success) (Rutherfurd et al. 2007). should also be considered. For nutrient filtration, areas of diffuse overland flow should be identified as hotspots of nutrients Promoting natural regeneration of vegetation entering the riparian zone and the stream. is generally the easiest, most cost effective and Perennial grasses or sedges planted to cover most ecologically efficient approach to managing contour banks or swales on the outer edge of the riparian areas, especially in agricultural landscapes. riparian buffer can be important for trapping Preserving existing mature trees whilst planting more will also work to maintain and restore 16 Table 2. Riparian ecosystem functional attributes and management guidelines Management goals & priorities Function Attribute Guideline Reference Shading Vegetation height Trees 5-20 m height Sweeney & Newbold 2014 Vegetation type Local native trees, eg. Eucalyptus rudis, Melaleuca rhaphiophylla in the SW Penn 1999 Vegetation density High density (75%), continuous cover with several layers (Trees, tall shrubs) Bunn et al. 1999 Buffer width Ten to 30 m wide (2 to 3 tree width) Sweeney & Newbold 2014 Bank Buffer width Minimum 10 m width from the top of the bank Rutherfurd et al. 2007 stabilization & sediment Vegetation type Include different plant structural types (trees, shrubs, grasses/sedges) Malanson & Bultler 1990 filtration Root type & density Replant across a potential bank failure plane Brooks et al. 2003 Position Planting trees low on a stream bank to increase bank resistance to slumping Rutherfurd 2007 Nutrient Vegetation type Include different plant structural types (trees, shrubs, grasses/sedges) Prosser et al. 1999 filtration Buffer width Minimum 10 m width from the top of the bank. Grass/sedge buffer strip at the outer Haycock et al. 1997 edge of riparian zone Terrestrial/ Vegetation type Maintain native trees with overhanging branches that contribute leaves (C), flowers, Nakano & Murikami 2001, Bunn Aquatic fruits and terrestrial invertebrates to the stream whilst reducing erosion. Maintain et al. 2003 Trophic aquatic vegetation for fish nurseries subsidies Ground cover Reduce weeds, fire and other disturbances that reduce litter cover Catford et al. 2011 Vegetation structure Maintain structure for terrestrial invertebrates and birds Lynch & Catterell 1999 Aquatic Vegetation type Encourage growth of aquatic plants and tree roots within the water column Cadwaller et al. 1980 habitat Woody debris & leaf Place LWD with different orientations to bank and flow (parallel, angled, Treadwell 1999; Pusey & litter perpendicular). Leave overhanging tree branches. Retain leaf litter in pools and Arthington 2003, Pettit et al. 2012 backwaters Terrestrial Vegetation type Retain native vegetation or local species, including plants with a range of food Lynch & Catterell 1999 habitat sources. Retain old trees with nesting hollows Vegetation structure Include different plant structural types (trees, shrubs, grasses/sedges) Loney & Hobbs 1991

Woody debris & leaf Retain leaf litter, and retain or add woody debris as microhabitat for fauna MacNally et al. 1990, Pettit et al. litter 2007 Fire Reduce fire frequency, maintain fire suppressant buffers (30m at creeks, 50m at 2Rog Consulting 2019, Pettit & rivers) Naiman 2007 Weeds Weed removal, encourage or plant natives. Fence to reduce disturbances (fire, Catford et al. 2011 recreational) Establishing a restoration framework

There rea many on-ground actions that can be A management framework for the protection and Management should prioritise key processes that implemented to repair riparian areas. However, restoration of riparian lands requires particular affect ecological condition and the capacity of certain actions will be more important than others guidelines that include: riparian ecosystems to support critical functions given the particular environmental setting or the and ecosystem services. This includes managing ecological functions requiring attention (Figure 2). • a common understanding in the community flooding, stream erosion, sediment & nutrient and managing agencies of the importance of delivery, riparian vegetation condition and Furthermore, some actions may not be possible riparian land; disturbance, particularly human activity. given current riparian conditions or relevant • a set of goals and objectives that are specific given the management objectives for the site. for the particular stream and riparian area to Consequently, we suggest that managers undertake be managed, including clear priorities, tools to a prioritization process to determine which actions provide guidance and measurement of progress they should implement at a given restoration site. towards objectives and targets; • mechanisms to encourage and facilitate riparian management in accordance with the stated goals and objectives; and • clear responsibilities for riparian management and monitoring. Eucalyptus coolabah ssp arida woodland, 2013.

18 Figure 2. Conceptual diagram of keys to preparation of management plan for riparian areas. The initial steps for the successful management of riparian buffers include consideration of the particular features of the environment to be managed, including the physical and catchment characteristics, as well as hydrology, vegetation and soils. Social and physical aspects of the human environment are also important in the evaluation of threats and purpose that, along with the type of environment, will inform the type and level of restoration and protection required. 19 Protecting and restoring riparian ecosystems ... To improve water quality Riparian vegetation protects banks from surface the stage of floods (Rutherford et al. 2007). For Management practices should firstly preserve erosion by rain, water flow or other disturbances. downstream reaches, riparian vegetation will and improve existing native riparian vegetation The roots of riparian vegetation can help to dry reduce the depth of flooding, however it is to provide a minimum 10 metre width upslope and reinforce bank soils to prevent cracking and important to keep in mind that the decreased from top of riparian bank. In most cases, it is slumping. flow depth created by riparian vegetation comes better to replant with native species where possible at the cost of slightly longer flood durations. (especially groundcovers) and ideally, include a The existing native riparian vegetation should For revegetation in the stream zone careful grass (or dense sedge) strip to maximize nutrient provide a minimum width upslope from the top of consideration needs to be made of the effects on stripping capacity. the bank of 5 metres, plus the height of the bank, stream flow and in particular flooding. When plus an additional width if the bank is actively restoring LWD to a river, they should be placed Sediment is deposited from overland surface flows eroding (Rutherfurd et al. 2007). The erosion at a variety of locations, generally on the outside when the flow is slowed down. This effectively traps allowance is calculated as the rate of bank erosion and downstream of a bend to reduce bank erosion. the sediment, absorbs nitrogen and phosphorus, in metres per year, multiplied by the number of For a comprehensive discussion on managing the as well as other solid particles and contaminants years it will take for replanted vegetation to reach a effects of riparian vegetation on stream flooding within the filter vegetation. The optimum riparian height of 10 metres. and bank erosion see Rutherford et al. (2007). buffer width will be based on site characteristics such as slope, soil type, and rainfall intensity, On larger streams, the natural process of channel To reduce light and temperature to the stream etc. Other considerations will include the type migration is usually around 1% of the channel width per year so that around half a channel The shade provided by the canopy of riparian trees of existing vegetation, landform shape, upslope reduces the effects of sunlight, reducing water development, the type and quantity of pollutants width is the distance on each side of a river for the riparian buffer. The key principle in preventing or temperature and light for photosynthesis, critical and the intensity of run-off (Sweeney & Newbold for in-stream biota and processes. The aim for 2014). reducing erosion is to maintain a good covering of perennial vegetation across the soil surface. This restoration should be to have 75% riparian cover should include relatively shallow rooted grasses across the stream (for a sub-catchment >1000 To reduce bank erosion and sedges and deeper-rooted shrubs and trees to ha, or the active channel >10 m). This requires The key erosion processes for rivers include sub- reduce or prevent surface erosion as well as bank tall trees in high density, at the top of the bank to aerial loosening, fluvial scour and mass failure slumping and scouring. provide maximum shading of the stream. and the major factors influencing these are bank materials, geometry and hydrology. Riparian A major outcome of removing riparian vegetation Where preserving or replanting riparian buffers for vegetation generally has a second order impact and wood from streams has been the changes improved canopy cover, 2 to 3 tree widths is ideal. on bank erosion processes, but this can still be in channel form (widening, deepening and Riparian buffers may therefore vary from between important in slowing erosion to an acceptable rate. straightening). Revegetating riparian zones, or 5–20 metres in width depending on the tree species adding large wood to stream channels, increases used and the site. 20 Protecting and restoring riparian ecosystems ... To provide habitat and food for in-stream and riparian corridors suitable for terrestrial animals riparian biota may need to be much wider to adequately fulfill this management objective. Recommended Native riparian vegetation provides inputs of leaves, riparian buffer widths are 30m for creeks and 50m woody debris, fruits, and insects which provide for rivers (2Rog Consulting 2019). It should also be a subsidy for aquatic food webs and ecosystem noted that retention of dead standing trees or trees processes. Two to three tree widths (10–20 m) is with large dead limbs is recommended as the tree ideal, with a number of different vertical layers hollows are important nesting sites for birds (e.g. including groundcover plants, shrub layers and a galahs, cockatoos). Talbragar River in Cobbora NSW, one canopy layer. month prior to flooding, 2009. A minimum of one tree or tall shrub width (5–10 m) will still provide inputs if it has a healthy crown overhanging the stream. Leaves that fall into the stream provide the base sources of carbon for in- stream foodwebs, particularly in highly shaded, low nutrient conditions. Leaf chemistry and aquatic micro-organisms can play an important role in the degradation of this OM which can subsequently support aquatic consumers (Pettit et al. 2012b).

Branches and whole trees that fall on the ground and into the stream (LWD) also provide critical habitat for terrestrial and aquatic organsims, as well as altering flow velocities to produce different habitat conditions for in-stream animals.

A riparian width of at least 10 m will also provide habitat and corridors for small animals including riparian birds. Due to detrimental edge effects

21 Figure 3. Pathway to successful restoration of riparian buffers starts with an imperative to assess the conditions of the riparian zone under focus. Questions that need to be kept in mind include: What is needed to reverse the causes of ecosystem degradation? Can we achieve restoration by simply removing the stressors or will further action be needed? We then need to identify strategies that focus on abiotic manipulations such as removing degrading factors (stress) and repair physical/chemical environment, before biotic manipulations such as replanting.

22 How to maintain & rebuild a riparian buffer Characteristics of the natural ecosystem that need There is wide variation in the condition of riparian There should also be a provision for a further to be considered in restoration ecology include zones of streams in Australia. These can include buffer strip that extends into the area of terrestrial composition, structure, pattern, heterogeneity, streams with relatively intact riparian buffers, to vegetation (verge). In general, high gradient function and resilience (Hobbs & Norton 1996). heavily degraded streams with little cover from streams have narrow riparian strips where as low The likely success of natural regeneration following riparian trees and invasion of the stream by exotic gradient streams have diffuse, wide riparian areas. the removal of degrading factors will depend on plants, so that they have little ecological value and While there are general principles that apply how they have affected these ecosystem functions require extensive work and high cost to rehabilitate. across all riparian areas, each will require specific (Brown & Lugo 1994). management needs. Therefore as each watercourse The first step in managing riparian buffers is to is unique, it is best to assess the area of the riparian If degradation of the riparian zone has affected properly identify the extent and variability of the zone that requires active management on a case- only biotic components of the ecosystem, such riparian zone. This includes the stream channel, by-case basis and the effectiveness of riparian as through the removal of the vegetation, then natural flooded area, floodway and flood zone. buffer system depends on factors that can only be removal of this stress can result in fairly rapid addressed at the local scale (Naiman et al. 2005). recovery without further management intervention (Allen et al. 1994). However, if the degradation has affected the base or ecosystem processes, such as the soil or hydrology, restoration may require more complicated and costly intervention (Milchunas & Laurenroth 1995).

The restoration of degraded systems to some desired state (whatever this may be) in ecological terms requires the re-initiation of successional processes by accelerating biotic change (Luken 1990). Six key steps in achieving this outcome are (see also Figure 3):

1. identify natural ecological, physical and social values; 2. identify degrading processes / threats; 3. develop methods to reverse the degradation; 4. determine realistic goals; 5. develop observable measures of success; and 6. develop practical techniques and communicate results. 23 Riparian buffer widths

Although there is a broad consistency about the Adequate riparian buffer zones perform the general widths recommended for riparian areas, following functions: there are differences depending on the purpose of riparian protection, types of stressors, physical • Reduce water runoff from surrounding land attributes of a particular stream and position into the . within the catchment. For example the clearing of • Reduce the amount of sediments, contaminants the upstream catchment will increase stream flow and nutrients in this runoff. and cause the river channel to widen downstream, • Prevent invasion of exotic plants. causing the riparian zone to be degraded or eroded • Provide corridors for wildlife movement. away altogether. • Provide a transition between upland and lowland habitats. Provisions for future protection may need to be made in catchments with low disturbance but By enhancing the ability for riparian zones to forecast to undergo intensive development. This perform their key ecological functions, in turn could be in the form of setting wider buffer strips ecosystem services will also be enhanced. to compensate for losses that occur as the riparian buffer falls into the channel (Vietz et al. 2014). • Natural pest control as insectivores are offered more habitat to roost in Overall, buffers ≥ 30 m wide are needed to protect • Regulation of water quality the physical, chemical, and biological integrity of • Denitrification of the soil small streams (<100 km2). The buffer zone should • Land stability also include a small additional area to minimise • Shading & drought refuge edge effects and to accommodate successive • Enhanced timber and pasture production degradation of the buffer edge, effectively • Enhanced diversity of native flora and fauna protecting native riparian vegetation and habitat at the streamside. This could be in the form of planted grassy or low shrub areas that can absorb water and nutrient run-off and create a barrier against weeds moving into the riparian areas.

Eucalyptus camaldulensis on the banks of the Burke River, Boulia, Queensland, 2019. 24 Riparian buffer widths Protecting and revegetating riparian zones

To protect intact or replanted riparian vegetation Short-term objectives Protection and repair of riparian areas should also requires firstly the elimination or reduction of include: the disturbing element such as flooding, fire, 1. Develop priorities for restoration of riparian • Ensure an adequate fertiliser action plan is in pests or human use. Some type of fencing and the vegetation through river and catchment place (particularly important for poor sandy creation of buffer strips is a minimal requirement planning processes, regardless of land tenure soils); in most cases. Where some intact vegetation and jointly with other remnant vegetation • Use soil remediation methods to improve the exists the easiest, most cost effective management management. nutrient holding capacity of soils; is to encourage natural regeneration. The active 2. Actively manage and restore healthy native • Maintain or improve the stores of carbon replanting of riparian areas requires: riparian vegetation in priority areas. within riparian soils by limiting disturbance 3. Protect remnant native riparian vegetation and planting native vegetation; and • Careful planning and plant selection; through existing statutory and planning • Native riparian vegetation, providing a complex • Site stabilization using earthworks, riprap, processes. community of trees ,understorey, groundcover LWD, commercial matting; and streamside sedges, should be planted where • Extremely important to control weeds and Long-term objectives it is lacking. pests; • Soil preparation such as ripping; 1. Wherever possible protect and establish • Soil amelioration such as gypsum or mulch; continuous corridors of native riparian • Correct seedling planting time and densities; vegetation, of suitable width, structure and • Decide whether to replant seedlings or use composition to ensure maintenance of direct seeding; ecological processes, along all streams. • In some cases watering in the first summer may 2. Re-establish ecological processes and be necessary; and biodiversity in riparian areas along streams. • Fencing to protect the newly replanted areas from stock and native grazers (e.g. wallabies). In many cases we can combine the recommended management operations so that they can meet The conservation and management of riparian different objectives. For example, a 10–20 metre buffers should include considerations of immediate wide grass filter strip could be combined with and short term needs but also with sufficient the replanting of native vegetation immediately planning and thought into the effects for the adjacent to a stream or creek to meet the multiple future is required. Therefore management should objectives of trapping sediment and nutrients, consider both short and long term aims and while also providing shade to the stream. objectives for riparian management and could include: Balonne River in St George, during drought, 2003. 25 It should be kept in mind that there are several • What are the unique features of the ecosystem When setting restoration goals we need to focus levels of management intervention that can be to be managed? on both potential short- and long-term outcomes undertaken and they each have different costs and • What are the major stressors and their sources? and where possible use reference systems. There benefits that need to be weighed up. Choosing • What is needed to reverse the causes of should also be a focus on desired goals for the which level of intervention is required will depend ecosystem degradation? future, rather than on the past societal desires to a large extent on costs and ambition. In • Can we achieve restoration by simply removing and economic constraints. Finally, monitoring, ecological terms, full restoration of a disturbed the stressors or will further action be needed? assessment and reporting is an essential site is almost impossible because loss of species, requirement for the management and rehabilitation processes and changed conditions make full re- We then need to identify strategies that focus projects for riparian areas. This should detail steps establishment highly unlikely. Also, the costs and on biotic manipulations such as removing in decision-making processes, methods of active time needed to fully restore a site are prohibitively degrading factor (stress) and repair physical/ management undertaken and detailed assessment high in most cases. chemical environment, before undertaking biotic of what worked, what didn’t and why. manipulations such as replanting. When setting Most interventions are likely to be at the level of goals we need to consider the particular attributes rehabilitation or reclamation: of the system to be restored and how the stressors are leading to degradation. This will determine the • Restoration - re-establishment of former types of actions that are required. functions and characteristic species and The Balonne River at St George, 2008. communities. Generally not possible at landscape scale because of conflicting land-use, public support and high costs; • Rehabilitation - Restore selected ecosystem functions in part of the landscape. Does not necessarily lead to significant increase in biodiversity in the whole landscape. Practical at an intermediate scale; • Reclamation- Increasing biodiversity per se, E.g. making land fit for cultivation. Appropriate at landscape scale.

Pathways to successful restoration of riparian buffers are summarized in Figure 3. This starts with the assessment of the local conditions and questions that need to be kept in mind which include:

26 Figure 4. Adaptive management of riparian management whereby defining goals is the critical first step in riparian management and restoration. The conceptual diagram emphasises flow of decision sequence and feedback mechanisms that allow assessment and linkages to make appropriate and timely adjustments (adapted from Davies et al. 2014).

27 Monitoring & evaluation The before and after monitoring, assessment and Monitoring ecosystem processes provides a often poorly done, with either no documentation evaluation should be seen as an integral part of direct measure of whether functions have been or not freely available. Published documentation the management of riparian land (Figures 2 and restored. This can include measuring nutrient is required to communicate all success and 3). Developing an appropriate monitoring plan is cycling, migration, hydrological flows or failures and should also include documenting all critical and should consider what to monitor, and plant recruitment. Where possible it can be very decisions and steps taken in the process. Effective could include particular key species, populations useful to select a range of reference sites to assess monitoring and documentation of results of or processes. Other possibilities for monitoring the natural variation in local riparian areas and riparian management and restoration will feedback could include level of recruitment, age structure, define boundary conditions for parameters to be into adjusting and refining the setting of goals and taxonomic assemblages or communities. Surrogate monitored. implementation of management actions (Figures 2 measures can also be used such as habitat variables, and 3). indicator or umbrella, sensitive and representative species. It is therefore important to identify Evaluation of restoration or management programs potential indicator species. For example, umbrella should be more than reporting on whether the species represent a range of ecological needs and action is following the agreed schedule and responses. Community metrics such milestone. Monitoring and evaluation must involve as species richness and composition, colonisation measuring over time whether the required changes rates or ratio of native to exotic species are also in condition (e.g. less bank erosion, lowered water commonly used. temperature, increased in-stream habitat) have been achieved as a result of the management The appropriate indicator chosen should be: action.

• directly linked to a key aspect or condition, Key elements to proper evaluation should include: function or pressures (stressors); • Selection of appropriate indicators, • detect change at the required spatial and • Consideration of appropriate spatial and temporal scales; temporal scales, • unambiguous and sensitive to changes • Consideration of frequency of measurement, anticipated. • Collection of baseline data at the • easily and cheaply measured using existing commencement of a monitoring program, methods, with a high degree of accuracy and Judging success needs adequate measures of • The use of multiple reference sites with which repeatability. progress toward agreed-upon goals and objectives. to compare the rehabilitated site. We need to monitor and evaluate these measures to understand why some projects succeed and others fail. Adequate reporting is essential but 28 Where no comparison with other sites is possible, Proper monitoring and evaluation procedures the collection of adequate baseline data from the also provide a basis for adaptive management Monitoring & evaluation treated site becomes very important. Effective and continued improvement, and can assist in evaluation requires consideration of the scale identifying priorities when resources are limited. and frequency of measurement, and potential Adaptive management applied to riparian buffers difficulties of separating treatment effects from whereby defining management or restoration natural variability. Comparison with reference sites goals is the critical first step, which must take is the preferred, but is not always possible. Selection into account society as well as ecological values. of indicators for monitoring programs should Particularly in rural and urban settings, people reflect the questions being asked in the evaluation. form part of the ecosystem in their use of this Develop appropriate performance indicators for resource and providing feedbacks onto riparian this threatening process to assist land and water condition is important to initiate appropriate management authorities in environmental audit responses (Groffman et al. 2003). and condition of catchment requirements. There are primary and other possible feedback Several methods have been developed for mechanisms that allow assessment of riparian appraisals of environmental condition of management actions and the linkages required waterways. These are especially valuable where to make appropriate and timely adjustments and, repeated assessments are required, using non- as well, the importance of suitable research on technical assessors, and over a large number of riparian and stream ecology relationships (Fig. sites. They often use surrogate indicators for ease 4). When adaptive management is embedded into and speed, and are suitable for situations where the operational management of riparian zones, trends over time are more important than absolute the monitoring and evaluation of outcomes for measures. Two rapid appraisal methods suitable species and processes can be used to assess the for riparian zones on rivers in southern (Jansen et effectiveness of management to refine and adapt al. 2005) and northern Australia (Dixon et al. 2006) practices (Fig. 4). Adaptive management also needs have been widely tested and applied and provide to be forward thinking and allow for unexpected useful information on the current condition of results. riparian areas. In Western Australia an index of river condition has been developed to assist in the management of waterways (http://water.wa.gov. au/water-topics/waterways/assessing-waterway- health/south-west-index-of-river-condition). This uses a range of standardized indicators to assess riparian condition. Barcoo River, near Tambo, Queensland, 2012.

29 Glossary Acidification -The process of a substance increasing in Eutrophication - When a body of water becomes inundated Regrowth vegetation - The vegetation growing in an area that acidity. In soils, this occurs when hydrogen cations build with excess nutrients, generally resulting in an overgrowth of had previously been cleared. up after the addition of an acid, such as nitric, carbonic or algae. Remnant vegetation - Vegetation remaining in its original sulfuric acids. Fluvial scour - The erosion of river beds or banks, occurring form or state without human disturbance. Adsorb - The adhesion of particles from a substance to the gradually or periodically as in the event of flooding. Riffle zone A- shallow stream segment where water flow is surface of a solid particle. For example, organic compounds Food-web subsidy - The addition of resources, such as affected by rocks. can adsorb on to the surface of soil particles. nutrients, detritus or prey, to one system from another. Riparian - Relating to the banks of a river. Aridity - A lack of moisture. An area is arid when it is severely Fragmentation - Refers to the splitting into smaller sections deficient in available water. Riprap - Loose stone forming the foundation of a streambed or fragments of a whole. or breakwater. Biodiversity - A measure of the variety and variability of all Heterogeneity - The state of being diverse in content or life on Earth, at a genetic, species and ecosystem level. Semi-arid - Receives little rain, but not as low as a desert. character. Buffer zone -A strip or area of vegetation or land between Subsidence - The sudden or gradual sinking or caving in of Hydraulics - The way water moves; often describing surface two zones. I.e. riparian vegetation offers a buffer zone to the land. flow or variation. water body from farmland or urbanisation. Substrate - The surface on which something lives or grows. Hydrology - The study of the distribution, movement and Carbon sequestration - The act of carbon dioxide being taken management of water. Sub-aerial loosening - The loosening of soil or rock from from the atmosphere and held in liquid or solid form. below the surface. Levee - An embankment or ridge of sediment at the edge of a Corridor - Wildlife, habitat or green corridors are stretches of river. Can form naturally through sediment deposition, or can Sustainability - Avoidance of natural resource depletion to habitat that connect larger areas of quality habitat, allowing be artificially designed to prevent river overflow. ensure an ecologically balanced system. fauna to travel between patches safely. Large woody debris (LWD) - Dropped tree branches or Swale - A shallow channel for water catching with gently Denitrification -A process in soil where bacteria utilises dead tree trunks, for example, that contribute to the riparian sloped sides. nitrates for respiration in place of oxygen, resulting in a loss or ecosystem. Terrestrial - Of or pertaining to the land or ground. reduction of available nitrogen. Mass failure (erosion) - Also known as collapse or slumping, Trophic - Relating to feeding or nutrition. Trophic level refers Ecological function - An ecosystem’s potential to deliver mass failure occurs when whole sections of riverbank erode to position in the food chain. ecosystem services. and slide into the stream. Urban heat island effect -The retention of heat in urban Ecosystem services - The outputs or processes of natural Nitrification -The addition of oxygen molecules to ammonia areas due to replacement of vegetation with hard surfaces. systems that can benefit humankind, either directly or to form nitrite, then nitrite to form nitrate. through the provision of other goods and services. Water table - The boundary between surface soil and the Primary succession - The growth of vegetation in an upper level of underground soil or rocks that are saturated Ecotone - An area of transition between two distinct otherwise previously lifeless area. with water. biological communities. Propagule - A plant structure that can detach from the parent Erosion - The result of surface processes that remove soil, plant to grow as a new plant, such as a bud or spore. rock or other material away from their original position. Photo Credits Flood Barmah forest river red gums (p. 1). From Barmah A gnarled paperbark tree on the edge of a lake on Fraser Island, Darling River at Menindee, NSW (p. 28). From Darling River, National Park, by CSIRO, 2007 (https://commons.wikimedia. Queensland (p. 13). From Lakes of Queensland, by Keith by Mattinbgn, 2009 (https://commons.wikimedia.org/wiki/ org/wiki/File:CSIRO_ScienceImage_4471_Flooded_Barmah_ Sinclair, 2014 (https://commons.wikimedia.org/wiki/File:A_ File:MenindeeDarlingRiver.JPG). CC BY-SA-3.0. forest_river_gums_VIC.jpg). CC BY-SA-3.0. gnarled_paper_bark_tree_on_the_edge_of_a_Fraser_Island_ Barcoo River, near Tambo, Queensland (p. 29). From Lake.jpg). CC BY-SA-4.0. Eucalyptus camaldulensis, the river red gum (p. 3, top photo). Queensland riverbanks, by Wittylama, 2012 (https://commons. From river red gum, by John Robert McPherson, 2019 (https:// Lachlan River at Booligal, NSW (p. 14). From Lachlan River, wikimedia.org/wiki/File:Barcoo_river,_Tambo.JPG). CC BY- commons.wikimedia.org/wiki/File:Eucalyptus_camaldulensis_ by Tim J Keegan, 2009 (https://www.flickr.com/photos/ SA-3.0. Burke_River_Boulia_P1060550.jpg). CC BY-SA-4.0. suburbanbloke/4997299727/). CC BY-SA-2.0. Coolibah at Combo Waterhole Queensland (p. 3, middle Eucalyptus coolabah ssp arida woodland (p. 18). From All other photos taken by authors. photo). From Combo Waterhole Queensland, by Alun Hoggett, Coolibah, by Mark Marathon, 2013 (https://commons. 2006 (https://commons.wikimedia.org/wiki/File:Combo_ wikimedia.org/wiki/File:Coolibah.jpg). CC BY-SA-3.0. Waterhole-Alun_Hoggett.jpg). CC BY-3.0. Talbragar River, at Cobbora NSW, November 2009, one month Tangled lignum (Meuhlenbeckia florulenta) habit (p. 3, bottom prior to flooding (p. 21). From Talbragar River, by Eregli bob, photo). From tangled lignum, by Mark Marathon, 2013 2009 (https://commons.wikimedia.org/wiki/File:Talbragar_ (https://commons.wikimedia.org/wiki/File:Ligmum.jpg). CC River,_at_Cobbora_NSW,_November_2009.jpg). CC BY- BY-3.0. SA-3.0. Eucalyptus camaldulensis reflected in the Burke River, Boulia, Belyando riverbank in central Queensland. From Queensland (p. 4). From river red gum, by John Robert Central Queensland: Galilee Basin (p. 23), by Lock the McPherson, 2019 (https://commons.wikimedia.org/wiki/ Gate Alliance, 2012 (https://www.flickr.com/photos/ File:Eucalyptus_camaldulensis_reflected_in_the_Burke_River_ lockthegatealliance/8353582422/in/set-72157632603956115). early_morning_Boulia_Queensland_P1060926.jpg). CC BY-SA CC BY-SA-2.0. 4.0. Eucalyptus camaldulensis on the banks of the Burke River, Peaceful Dove (Geopelia placida), Glen Alice, Lithgow, NSW, Boulia, Queensland (p. 24). From Eucalyptus camaldulensis, by Australia (p. 7). From Geopelia placida, by JJ Harrison (https:// John Robert McPherson, 2019 (https://commons.wikimedia. www.jjharrison.com.au/), 2019 (https://commons.wikimedia. org/wiki/File:Eucalyptus_camaldulensis_Burke_River_Boulia_ org/w/index.php?curid=83889317). CC BY-SA 4.0. Queensland_P1060517.jpg). CC BY-SA-4.0. ‘Enjoying the scenery near the Balonne River Bridge, Balonne River in St George, Queensland, during drought St. George, ca. 1917,’ (p. 9, top photo). From St George, (p. 25). From St George, Queensland, by Vinko Rajic, 2003 Queensland, by unknown (item is held by John Oxley Library, (https://commons.wikimedia.org/wiki/File:St_George_,_ State Library of Queensland), circa 1917 (https://commons. Baloone_River,_drought_-_panoramio.jpg). CC BY-SA-3.0. wikimedia.org/w/index.php?curid=12667133). CC BY-SA 2.5. The Balonne River at St George, Queensland (p. 26). From St Aboriginal fish traps, Barwon River, Brewarrina, NSW (p. 9, George, Queensland, by Mattinbgn, 2008 (https://commons. bottom photo), Australia. From Brewarrina Aboriginal Fish wikimedia.org/wiki/File:StGeorgeBalonneRiver.JPG). CC BY- Traps, by Conollyb (https://commons.wikimedia.org/w/index. SA-3.0. php?curid=7112024). CC BY-SA 3.0.

31 References 2rog Consulting (2019). Projects. 2rog Consulting. Retrieved Günther (Pisces: Galaxiidae). Australian Journal of Marine Haycock, N. E. & Pinay, G. (1993). Groundwater nitrate from www.2rog.com.au/projects/. and Freshwater Research, 31, 257–62. dynamics in grass and polar vegetated riparian buffers during winter. Journal of Environmental Quality, 22, 273-278. Abbe, T. B., Brooks, A. P. & Montgomery D. R. (2003). Wood Capon, S., Balcombe, S. R. & McBroom, J. (2017). in river rehabilitation and management. In S. V. Gregory, K. L. Environmental watering for vegetation diversity outcomes Haycock, N., Burt, T., Golding, K. & Pinay, G. (Eds.). Boyer & A. M. Gurnell (Eds.), The ecology and management must account for local canopy conditions. Ecohydrology, (1997). Buffer Zones: their processes and potential in water of wood in world rivers (pp. 367–90), Bethesda, Maryland, 10(6), e1859. Protection. Quest Environmental, Harpenden, Hertfordshire, American Fisheries Society, Symposium 37. UK. Chauvet, E. & Decamps H. (1989). Lateral interactions in a Bayly, I. A. E. and Williams, W. D. (1981). Inland and fluvial landscape: The river Garonne, France. Journal of North Loney, B. & Hobbs, R. J. (1991). Management of vegetation their ecology. Longman Cheshire, Melbourne, Australia. American Benthological Society, 8: 9-17. corridors: maintenance, rehabilitation and establishment. In D. A. Saunders & R. J. Hobbs (Eds.), Nature Conservation Beesley, L. (1996). The ecological importance of large woody Davies, P. M., Bunn, S. E. & Hamilton, S. K. (2008). 2 - 2: the role of corridors (pp. 299-311). Surrey Beatty & Sons, debris in the sandy river systems of the Swan coastal plain Primary Production in Tropical Streams and Rivers. In D. Chipping Norton. (Perth, Western Australia)’ [Honours thesis, University of Dudgeon (Ed.) Tropical Stream Ecology: A volume in Aquatic Western Australia]. Perth. Ecology (pp. 23-42). Academic Press. https://doi.org/10.1016/ Lowrance, R., Todd R., Fail J., Hendrickson O., Leonard R. B978-012088449-0.50004-2 & Asmussen L. (1984). Riparian forests as nutrient filters in Brooks, A. P., Brierley, C. G. & Millar R.G. (2003). The agricultural watersheds. Bioscience, 34, 374-377. longterm control of vegetation and woody debris on channel Groffman, P. M., Bain D. J., Band L. E., Belt K. T., Brush G. and flood-plain evolution: Insights from a paired catchment S., Grove J. M., Pouyat R. V., Yesilonis I. C. & Zipperer W. Lovett, S. & Price, P. (Eds.). (2007). Principles for riparian study in southeastern Australia. Geomorphology, 51, 7–29. C. (2003). Down by the riverside: urban riparian ecology. lands Management. Land & Water Australia, Canberra. Frontiers in Ecology and the Environment, 1, 315–321. Bunn, S. E. (1993). Riparian-stream linkages: research needs Lovett, S. & Price, P. (Eds.). (1999a). Riparian Land for the protection of in-stream values. Australian Biology, 6, Fisher, A.M. & Goldney, D.C. (1997). Use by birds of riparian Management Technical Guidelines, Volume One: Principles 46-51. vegetation in an extensively fragmented landscape. Pacific of Sound Management. LWRRDC, Canberra. Conservation Biology, 3, 275–88. Bunn, S. E., Davies, P. M. & Winning, M. (2003). Sources Lovett, S. & Price, P. (Eds.). (1999b). Riparian Land of organic carbon supporting the of an arid zone Gurnell, A., Lee, M., & Souch, C. (2007). Urban Rivers: Management Technical Guidelines, Volume Two: On-ground floodplain river. Freshwater Biology, 48, 619–35. Hydrology, Geomorphology, Ecology and Opportunities for Management Tools and Techniques. LWRRDC, Canberra. Change. Geography Compass, 1(5), 1118-1137. https://doi. Bunn, S. E., Abal, E. G., Greenfield, P. F. & Tarte, D. M. Lynch, R. J., Bunn, S. E. & Catterall, C. P. (2002). Adult org/10.1111/j.1749-8198.2007.00058.x (2007). Making the connection between healthy waterways aquatic insects: Potential contributors to riparian food webs and healthy catchments: South East Queensland, Australia. Hairsine, P. B. (1996). Comparing grass filter strips and in Australia’s wet-dry tropics. Austral Ecology, 27, 515–26. Water Supply, 7(2), 93-100. https://doi.org/10.2166/ near-natural riparian forests for buffering intense hillslope Malanson, G. P. & Butler, D. R. (1990). Woody debris, ws.2007.044 sediment sources. In I.D. Rutherfurd (Ed.), Proceedings sediment, and riparian vegetation of a subalpine river, of the First National Conference on Stream Management Cadwallader, P. L., Eden, A. K. & Hook, R. A. (1980). Role Montana, USA. Arctic and Alpine Research, 22, 183–94. in Australia (pp. 203–6), Cooperative Research Centre for of streamside vegetation as food source for Galaxias olidus Hydrology, Melbourne. Malanson, G. P. (1993). Riparian Landscapes. Cambridge Pinay, G., Roques, L. & Fabre, A. (1993). Spatial and temporal Stream Restoration Working Group (FISRWG). University Press, Cambridge, UK. patterns of denitrification in riparian forests. Journal of References Vietz, G. J., Sammonds, M. J., Walsh, C. J., Fletcher, T. D., Applied Ecology, 30, 581-591. Naiman, R. J., Fetherston, K. L., McKay, S. J. & Chen, J. Rutherfurd, I. D. & Stewardson, M. J. (2014). Ecologically (1998). Riparian Forests. In R. J. Naiman & R. E. Bilby (Eds.), Poff, N. L., Allan, J. D., Bain, M. B., Karr, J. R., Prestegaard, K. relevant geomorphic attributes of streams are impaired River Ecology and Management: Lessons from the Pacific L., Richter, B. D, Sparks, R. E. & Stromberg, J. C. (1997). The by even low levels of watershed effective imperviousness. Coastal Ecoregion (pp. 289-323). Springer, New York, USA. natural flow regime: a paradigm for river conservation and Geomorphology, 206, 67-78. restoration, Bioscience, 47, 769–784. Naiman, R. J., Décamps, H. & McClain, M. E. (2005). Riparia, Wallace, J. B., Eggert, S. L., Meyer, J. L. & Webster, J. R. (1997). Ecology, Conservation and Management of Streamside Polis, G. A., Anderson, W. B. & Holt, R. D. (1997). Toward an Multipletrophic levels of a forest stream linked to terrestrial Communities. Elsevier Academic Press, Boston, MA. integration of landscape and foodweb ecology: The dynamics litter inputs. Science, 277, 102-104. of spatially subsidized food webs. Annual Review of Ecology Naiman, R. J., Latterell, J. J., Pettit, N. E. & Olden, J. D. (2008). Walsh, C. J., Fletcher, T. D., Bos, D. G. & Imberger, S. J. and Systematics, 28, 289-319. Flow variability and the biophysical vitality of river systems. (2015). Restoring a stream through retention of urban Comptes Rendus Geoscience, 340(9-10), 629-43. Price, P. & Tubman, W. (2007). Structure and characteristics stormwater runoff: a catchment-scale experiment in a social- of riparian lands. In S. Lovett & P. Price (Eds.), Principles ecological system. Freshwater Science, 35(3), 1161-68. Naiman, R. J. (2013). Socio-ecological complexity and the for Riparian Lands Management (pp. 1-12). Land and Water restoration of river ecosystems. Inland Waters, 3, 391-410. Weaver, D. M. & Reed, A.E.G. (1998). Patterns of nutrient Australia, Canberra. status and fertiliser practice on soils of the south coast Nakano, S. & Murakami M. (2001). Reciprocal subsidies: Rieman, B. E., Smith, C. L., Naiman, R. J., et al. (2015). of Western Australia. Agriculture, Ecosystems and Dynamic interdependence between terrestrial and aquatic A comprehensive approach for habitat restoration in the Environment, 67, 37-53. food webs. Proceedings of the National Academy of Sciences, Columbia Basin. Fisheries, 40, 124-135. 98, 166-170. Weaver, D. & Summers, R. (2014). Fit-for-purpose Richter, B. D. (1997). How much water does a river need? phosphorus management: do riparian buffers qualify in Peterjohn, W. T. & Correll, D. L. (1984). Nutrient dynamics Freshwater Biology, 37, 231-249. catchments with sandy soils? Environmental Monitoring and in an agricultural watershed: Observations on the role of the Assessment, 186, 2867-2884. riparian forest. Ecology, 65, 1466-1475. Saunders, D., Hobbs, R. & Ehrlich, P. (Eds.). (1993). Reconstruction of Fragmented Ecosystems. Surrey Beatty & Pettit, N. E., Weighell, S. & Ladd, P. (2007). Wetland Sons Pty Ltd, Sydney, Australia. vegetation monitoring: Jandakot Wetland 2006 Survey. Report for the Department of Water, Perth, Western Australia. Stewart, B. J., Close, P. G., Cook, P. A. & Davies, P. M. (2015). Upper thermal tolerances of key taxonomic groups of stream Pettit, N. E., Davies, T., Fellman, J. B., Grierson, P. F., Warfe, invertebrates. Hydrobiologia, 718, 131-140. D. M.& Davies P. M. (2012). Leaf chemistry, decomposition and assimilation by macroinvertebrates in two tropical Sweeney, B. W. & Newbold, J. D. (2014). Streamside buffer streams. Hydrobiologia, 680, 63-77. width needed to protect stream water quality, habitat and organisms: A literature review. Journal of the American Water Pinay, G. & Decamps, H. (1988). The role of woods in Resources Association, 50, 560-584. regulating nitrogen fluxes between the alluvial and surface water: A conceptual model. Regulated rivers: FISRWG (2001). Federal Stream Corridor Restoration Research and Management, 2, 507-516. Handbook (NEH-653): Stream Corridor Restoration: Principles, Processes, and Practices. Federal Interagency 33 September 2020

Acknowledgements

This handbook was produced as part of CRDC project GU1701 and is the result of the efforts of many. Major contributions were made by Dr Stephen Balcombe, Ms Peta Zivec, Dr Neil Pettit, Ms Laura McCallion, Ms Cara Parsons and Ms Stacey Vogel. Thanks is given to all those who contributed to workshops, surveys and interviews during this project.

For further information, please contact:

Assoc. Prof. Samantha Capon Australian Rivers Institute Griffith University