Riparian Management Practices Research Articles

The effects of pastoral hill country natural landscape features and land management practices on nitrate losses and its potential attenuation for improved water quality

AbstractPastoral farming on hill country landscapes influences nitrogen (N) dynamics and its losses to freshwater. This study reviewed the current literature identifying key effects of pastoral hill country landscape features and land management practices on nitrate losses to receiving waters. The review also highlighted the potential effects of inherent landscape features on nitrate attenuation pathways for better water quality outcomes. Intensive land use activities involving high rates of fertiliser application, higher stocking rates and cattle grazing, relative to sheep grazing, are more likely to increase nitrate loss, especially on lower slopes. However, soils with a high carbon (C) storage capacity such as allophanic soils potentially limit nitrate loss via denitrification in subsoil layers. Hill country seepage wetlands also offer an opportunity to attenuate nitrate loss, though their efficacy is largely impacted by hydrological variations in their inflows and outflows. By enhancing the natural nitrate attenuation capacity of seepage wetlands, mapping and strategic use of high subsoil denitrification potential, effective riparian management, efficient fertiliser and grazing practices and the incorporation of these farm management strategies into Freshwater Farm Plans (FWFPs), wider environmental and farm productivity/profitability goals, including improved water quality, would be achieved on pastoral hill country landscapes.

Non-rhizosphere reinforces the contributions of Feammox and anammox to nitrogen loss than rhizosphere in riparian zones

The emergence of anaerobic ammonium oxidation (anammox) coupled to iron reduction (named Feammox) refreshes the microbial pathways for nitrogen (N) loss. However, the ecological role of Feammox, compared with conventional denitrification and anammox, in microbial N attenuation in ecosystems remains unclear. Here, the specific contribution of Feammox to N loss and the underlying microbiome interactive characteristics in a riparian ecosystem were investigated through 15N isotope tracing and molecular analysis. Feammox was highlighted in the riparian interface soils and maximally contributed 14.2% of N loss. Denitrification remained the dominant contributor to N loss (68.0%–95.3%), followed by anammox (5.7%–19.1%) and Feammox (0–14.2%). The rates of Feammox and anammox significantly decreased in rhizosphere soils (0.15 ± 0.08 μg N g−1 d −1 for Feammox, 0.80 ± 0.39 μg N g−1 d −1 for anammox) compared with those in non-rhizosphere soils; however, the activities of denitrification remarkably increased in the rhizosphere (13.17 ± 3.71 μg N g−1 d −1). In rhizosphere soils, the competition between bioavailable organic matter (e.g., amino acids and carbohydrates) and ammonium for electron acceptor [i.e., Fe(III)] was the vital inducement for restricted Feammox, while the nitrite consumption boosted by heterotrophic denitrifiers was responsible for weakened anammox. The functional gene of autotrophic Acidimicrobiaceae bacterium A6, instead of heterotrophic Geobacteraceae spp., was significantly positively correlated with Feammox activity. Rare iron-reducing bacteria showed higher node degrees in the non-rhizosphere network than in the rhizosphere network. A syntrophic relationship was found between iron-reducing bacteria (e.g., Anaeromyxobacter, Geobacter) and iron-oxidizing bacteria (e.g., Sideroxydans) in the non-rhizosphere network and facilitated the Feammox pathway. This study provides an in-depth exploration of microbial driven N loss in a riparian ecosystem and introduces new insights into riparian management practices toward high-efficient N pollution alleviation.

Macroinvertebrate responses to differing riparian treatments following forest harvest in the headwaters of Trask River watershed

Although it is well-established that macroinvertebrates are an integral part of a healthy stream ecosystem, studies designed to inform forest harvest best management practices for sustainability of macroinvertebrate communities in small streams have been limited. Current riparian management practices for headwater streams generally focus on providing adequate wood supply, reducing debris flows and transport of sediment, and maintaining water quality in larger streams that contain fish. Here we studied the effects of contemporary forest harvest practices on benthic macroinvertebrate density and community composition in 12 small headwater streams as part of the Trask River Watershed Study. To account for seasonal and year-to-year variability in macroinvertebrate densities, we sampled each site at the same time of year for six years before and four years after harvest. Three watersheds were clearcut with variable riparian buffers, three were clearcut with 12 m riparian buffers, and one was thinned with 15 m buffers. Five adjacent watersheds were not treated and were studied as reference sites. All sites had approximately 50 yr old conifer and alder forests, which had revegetated following fires and harvest in prior decades.In these steep mountain streams, benthic macroinvertebrate density and community composition were generally similar across watersheds prior to harvest. Collectors were the most abundant functional feeding group, followed by shredders; scrapers were the least abundant. After harvest, in two of the three clearcut watersheds with variable buffers, the total benthic density and percentage of collectors increased, primarily due to greater numbers of Chironomidae. We also observed more abundant emergence post-harvest at these two watersheds. In the third clearcut watershed with a variable buffer and in the three clearcut watersheds with uniform 12 m riparian buffers, we did not see changes in density or functional feeding groups after harvest. We explored the spatial and temporal aspects of the data using both non-parametric and parametric statistical methods. High variability swamped the treatment effect when watersheds were grouped by riparian treatment for the repeated measure analyses, while NMDS showed a significant shift post-harvest for the watersheds with variable buffers. In the clearcut watersheds with uniform buffers, macroinvertebrates densities and community composition did not shift. At two of the clearcut watersheds with variable buffers, we observed increased density for the first two years after harvest, and chironomids comprised up to 80% of the abundance in samples. In the subsequent years, we documented mixed responses for two watersheds. It was invaluable to have multiple pre- and post-harvest sampling periods in both harvested and reference watersheds in order to better identify site specific responses to treatment and to separate background variability from responses to harvest. We show that retention of riparian vegetation on headwater streams during clearcut harvesting minimized changes in total macroinvertebrate densities and community composition. Small buffers may be key to maintenance of diverse stream invertebrate communities in headwaters.

The effect of riparian woodland cover on ecosystem service delivery by river floodplains: a scenario assessment

AbstractSixteen ecosystem services were quantified for the riverine landscapes of the Nahe, Stever (Germany), Bresse plain, and Azergues (France), to assess the effects of riparian woodland cover. Future woodland cover in 2050 was modeled to reflect contrasting scenarios of river management aligned to the well‐established shared socioeconomic pathways. The scenarios are labeled as current, pessimistic, best practice, and ambitious riparian management practices (RMPs). We linked services to floodplain land use and river morphology and quantified them separately for spatial segments (0.5–1 km in length, n = 118–3419, depending on river length), using an analytical framework, the “Mononen cascade.” Conservative monetary value estimates were based on net producer income before tax and subsidy, a shadow market price for carbon, flood damage functions, or willingness to pay for recreation and non‐use. Most services were linked to land use, some affected the value of other services through simple rules (woodland shade affected trout survival hence angling benefit, a minimum of woodland affected pest regulation, hence crop productivity). In the current landscape state, provisioning, regulating, and cultural services all showed optimum curves with woodland cover: Provisioning services and cultural services were maximal around 45%, whereas this was around 30% for regulating services. More woodland was present in steeper near‐source segments. Averaged across rivers, mean total service provision was estimated at 1084 ± 4 €·ha−1·yr−1, with 40%, 36%, and 24% contributed by, respectively, provisioning, regulating, and cultural services. The three scenarios led to a limited change in total ecosystem service delivery, even if mean woodland cover was reduced from 27% to 17% in the pessimistic RMP and increased to 70% in the ambitious RMP for the most extreme case of the Stever. Provisioning services declined with increased woodland cover and cultural services increased. Regulating services did not change that much, because they are dominated by flood prevention in our assessment. The “best practice” scenario appeared to combine a modest increase in cultural services with a slight increase in provisioning service. An ambitious nature conservation objective as in the ambitious RMP appears possible without seriously compromising overall societal benefit.

A laboratory study of flow characteristics in natural heterogeneous vegetation patches under submerged conditions

Existing studies on flow through vegetation have focused mainly on understanding the turbulent structure in vegetated channels of single plant type. However, in natural riverine environments, vegetation also occurs as patches with heterogeneous plant forms. The present paper investigates the flow and turbulent characteristics in heterogeneous vegetation patches at a laboratory scale. Experiments were conducted using different forms (grass, leafy and cylindrical) of natural vegetation planted, alternatively and also as a mixed variety of patches in a staggered pattern. The results show that the presence of other vegetation forms in mixed heterogeneous patch increases the velocity reduction up to 10% compared to flexible grass. Moreover, additional drag due to mixed vegetation reduces shear generated turbulence at the canopy top and shifts its peak above the canopy. In the case of heterogeneous patches, spatial heterogeneity in velocity fields and, varying zones of increased and diminished turbulence were observed. Specifically, patch form and its alignment significantly control the velocity reduction and, momentum transfer between the canopy and overflow regions. These findings and furthermore studies on heterogeneous patches may be helpful for riparian management practices in creating ecological and sediment deposition zones.

Assessing the long-term ecological effects of riparian management practices on headwater streams in a coastal temperate rainforest

Our understanding of how effective forestry Best Management Practices (BMPs) can mitigate logging impacts on the structure and functioning of temperate headwater streams tends to be based upon studies conducted within the first few years post-harvest. Little is known about how the affected biological parameters of streams change during riparian and upland forest regeneration, particularly the time taken to return to pre-harvest levels, or to within the range of reference conditions. By following up on an earlier study in southwestern British Columbia, Canada, we examined the post-logging recovery trajectories of stream attributes under multiple forest treatments. These treatments provided a gradient of riparian protection, including streamside clear-cutting with no reserves, and with fixed-width reserves (10m and 30m), and thinning with 50% basal area removal of riparian trees, which were compared with unharvested control sites. About 15years after clear-cutting and 9years after thinning, slower decomposition of red alder leaves (Alnus rubra) was reported in streams affected by forest harvesting, which was attributed to lower density of shredder invertebrates. Thinned reaches had lower litter decomposition rate than, but similar shredder density and richness to, unharvested reference sites. After a further 7years of forest regrowth (time elapsed between the previous and present study), we found that litter decomposition rate and shredder density in logging-affected reaches converged with values in reference reaches. Stream functional integrity, as reflected by litter decomposition, increased across all forest treatments. Some differences in rarefied shredder richness among forest treatments emerged in this study. The legacy effects of thinning on some biotic variables likely diminished more quickly (2–9years post-harvest) than those of clear-cutting with and without riparian reserves (8–15years). Stream recovery from thinning to reference conditions should continue to warrant attention, as wider, larger-scale partial harvesting practices are recommended within emerging paradigms of forest management. Overall, our findings indicate time scales towards recovery of an important ecological process of streams under common forestry practices, which could be longer than other stream properties, such as water quality. Such differences in recovery time frames should be considered for the planning of forestry operations and monitoring of harvesting legacies.

Riparian management affects instream habitat condition in a dairy stream catchment

ABSTRACTUsing a space-for-time substitution design, we investigated the response of structural instream habitat and fish populations to different riparian management practices throughout a Dairy Best Practice Catchment. We found a significant negative correlation between the upstream area of stock exclusion fencing and deposited instream fine sediment cover. Furthermore, we determined that this relationship emerges when ≥300 m lengths of upstream riparian area were included in the analysis, indicating the scale at which stock exclusion fencing results in a positive instream habitat response. Specifically, for this historically degraded spring-fed stream, our findings indicate that riparian segments with 5 m wide stock exclusion fences (both banks) are required to achieve instream fine sediment cover below 20% in downstream reaches. Fish were sparse and evenly spread throughout the catchment. Fish distributions were not correlated with reach-scale riparian or instream habitat variables, possibly because the available habitat quality gradient was too narrow.

Economics of riparian beneficial management practices for improved water quality: A representative farm analysis in the Canadian Prairie region

This paper examines the economics of adopting agricultural beneficial management practices (BMPs) to protect riparian areas in the Canadian Prairies. Monte Carlo simulation methods and cost/benefit analysis (net present value) are used to evaluate BMP adoption for a set of representative cropping and mixed farm operations in Alberta and Saskatchewan. BMPs considered in the analysis involve restoration, maintenance and/or protection of riparian areas and associated wetlands. Implementation of these BMPs by the representative farms is generally costly, resulting in negative net benefits. This is primarily due to opportunity costs from forgone returns and BMP establishment costs. The farm level results are combined with estimates of public values for riparian ecosystem services using the Pannell land use policy framework. Results indicate that in many cases, positive incentives, such as subsidies or conservation auctions, are appropriate policy responses to encourage increased production of riparian/wetland ecosystem services. Given the uncertainty in public and private benefit estimates, it may also be the case that no intervention is the optimal policy response in some instances. There is significant scope for further research in order to obtain better estimates of benefits and costs associated with riparian area management.Ce travail étudie les gains économiques obtenus en adoptant de meilleures pratiques agricoles de management (MPAMs) pour protéger les zones riparienne des Rocheuses Canadiennes. Nous combinons les méthodes statistiques de Monte Carlo et une analyse coût/bénéfice (valeur présente nette) pour évaluer l’adoption de meilleure pratiques pour un échantillon représentatif de fermes céréalières dans l’Alberta et la Saskatchewan. Les MPAMs considérées dans notre analyse impliquent la restauration, le maintien et/ou la protection des zones riparienne et des marais qui leur sont associés. La mise en place d’une MPAM est en général couteuse et réduit les bénéfices nets. Cette réduction est en grande partie due aux coûts de mise en œuvre de la MPAM et à la perte nette d’exploitation qui résulte de la MPAM. En nous aidant du cadre règlementaire de l’utilisation des terres développé par Pannell, les résultats obtenus à l’échelle de la ferme sont combinés avec les estimations des valeurs publiques pour des services des écosystèmes riparien. Nos résultats montrent que dans de nombreux cas des incitations positives telles que des subventions ou des enchères de conservation sont nécessaires pour encourager la production de services obtenus grâce aux écosystèmes riparien. Dans certains cas, étant donnée l’incertitude, il est possible qu’il soit optimal de ne pas intervenir du tout. Notre étude montre aussi l’importance de continuer les travaux de recherche dans le management des zones ripariennes.

Influence of grazing and land use on stream-channel characteristics among small dairy farms in the Eastern United States

AbstractRotational grazing (RG) is a livestock management practice that rotates grazing cattle on a scale of hours to days among small pastures termed paddocks. It may beneficially affect stream channels, relative to other livestock management practices. Such effects and other beneficial effects on hydrology are important to RG's potential to provide a highly multifunctional mode of livestock farming. Previous comparisons of effects of RG and confinement dairy (CD) on adjoining streams have been restricted in scale and scope. We examined 11 stream-channel characteristics on a representative sample of 37 small dairy farms that used either RG or CD production methods. Our objectives were: (1) to compare channel characteristics on RG and CD farms, as these production methods are implemented in practice, in New York, Pennsylvania and Wisconsin, USA; and (2) to examine land use on these farms that may affect stream-channel characteristics. To help interpret channel characteristic findings, we examined on-farm land use in riparian areas 50 m in width along both sides of stream reaches and whole-farm land use. In all states, stream-channel characteristics on RG and CD farms did not differ. Whole-farm land use differed significantly between farm types; CD farms allocated more land to annual row crops, whereas RG farms allocated more land to pasture and grassland. However, land cover in 50 m riparian areas was not different between farm types within states; in particular, many RG and CD farms had continuously grazed pastures in riparian areas, typically occupied by juvenile and non-lactating cows, which may have contributed sediment and nutrients to streams. This similarity in riparian management practices may explain the observed similarity of farm types with respect to stream-channel characteristics. To realize the potential benefits of RG on streams, best management practices that affect stream-channel characteristics, such as protection of riparian areas, may improve aggregate effects of RG on stream quality and also enhance other environment, economic and social benefits of RG.

How past riparian management practices can affect composition and structure of vegetation for headwater ecological restoration projects

Ecological restoration of river networks, especially of headwaters, is a key issue to improve water ecological, chemical and physical qualities and ecological functioning of aquatic ecosystems. Ecological restoration of degraded riparian vegetation is commonly considered as an efficient way to improve headwater habitats. This study aims to describe past management dynamics and their effect on current riparian vegetation structure and composition. We focused on two headwater brooks surrounded by traditional pasture in the rural catchment of the river Oir, a salmonid nursery of the river Sélune, Normandy, France. Historical riparian vegetation dynamic has been characterized thanks to interpretation of ortho-photographs from 1947 to 2010. GIS analyses allowed us to distinguish five types of management practices from stable vegetation (maintained open or maintained woody) to heterogeneous dynamic vegetation (alternation of clear-cutting, coppice management and recolonization by ligneous species). To measure their impact on the riparian ecosystem, past management practices were linked with field data describing current structure and composition of riparian vegetation. Results show that structure of riparian plant communities depends mainly on recent management practices, while floristic composition depends both on recent and past management practices. Knowledge of the past dynamics of riparian landscapes proves to be a relevant indicator of the ecological status of headwater ecosystems that could be used to improve ecological restoration instead of classical management practices of riparian vegetation.

Estimating sediment and phosphorus loads from streambanks with and without riparian protection

In some watersheds, the majority of the total sediment load to streams and rivers is from streambanks, but insufficient data exist on actual loading from this source and the potential protective effect of riparian protection in many watersheds. Using aerial imagery, video reconnaissance for unstable banks, and streambank phosphorus (P) sampling, this research studied streambanks throughout the Barren Fork Creek (BFC) watershed within Oklahoma to address four major objectives: (i) quantify the amount of streambank erosion and failure throughout the watershed, (ii) quantify the magnitude and the intra-site and inter-site spatial variability in streambank soil chemistry, water soluble phosphorus (WSP), and total phosphorus (TP), (iii) quantify the load of WSP and TP from streambanks in the watershed, and (iv) estimate the benefit of riparian management practices. Ten streambank study sites were selected on BFC, including seven sites with existing or historic riparian forest (historically protected, HP), and three with no riparian forest (historically unprotected, HUP). Median and mean streambank migration rates were 9.5 and 17.5m for the HP sites compared to 37.6 and 49.2m for the three HUP sites over the seven year period. Total WSP from streambanks on BFC from unprotected and failing banks was approximately 1.2×103kgyr−1, which represented approximately 10% of the dissolved P load estimated from USGS gauges on BFC. The estimated TP load was approximately 9.0×104kgTPyr−1, which exceeded the TP load estimated from gauge data, although TP is largely sediment-bound and thus subject to sediment transport dynamics such as floodplain deposition. Streambanks represented a considerable source of P, and riparian forest sites showed significantly lower rates of retreat. The methodology of using detailed P characterization, lateral retreat rates from aerial photography, and video reconnaissance to characterize bank stability was an effective approach for assessing the WSP and TP load contribution from streambanks.

Assessing Riparian Conservation Land Management Practice Impacts on Gully Erosion in Iowa

Well-established perennial vegetation in riparian areas of agricultural lands can stabilize the end points of gullies and reduce their overall erosion. The objective of this study was to investigate the impacts of riparian land management on gully erosion. A field survey documented the number of gullies and cattle access points in riparian forest buffers, grass filters, annual row-cropped fields, pastures in which the cattle were fenced out of the stream, and continuously, rotationally and intensive rotationally grazed pastures in three regions of Iowa. Gully lengths, depths and severely eroding bank areas were measured. Gullies exhibited few significant differences among riparian management practices. The most significant differences were exhibited between conservation and agricultural management practices, an indication that conservation practices could reduce gully erosion. Changes in pasture management from continuous to rotational or intensive rotational grazing showed no reductions in gully erosion. It is important to recognize that more significant differences among riparian management practices were not exhibited because the conservation and alternative grazing practices had recently been established. As gully formation is more impacted by upland than riparian management, gully stabilization might require additional upland conservation practices. The existence of numerous cattle access points in pastures where cattle have full access to the stream also indicates that these could be substantial sources of sediment for streams. Finally, the gully banks were less important sediment contributors to streams than the streambanks. The severely eroding bank areas in streams were six times greater than those in the gullies in the monitored reaches.

Soil and landscape influences on native riparian phosphorus availability in three Lake Champlain Basin stream corridors

The ability to rank riparian soils by native phosphorus (P) concentration could help prioritize riparian management practices aimed at reducing P loading from streambank erosion. The objective of this study was to explore the relationship between riparian soil variability and native P availability in three riparian corridors in northwestern Vermont. In the first study, two sites along tributaries of Lake Champlain were remapped at a high resolution (1:5000) by the USDA Natural Resources Conservation Service in 2006. After the remapping, multiple profile samples were taken from each series and were analyzed for total P (TP) and Modified Morgan extractable P. In a second study, 27 soil characterization pedons were sampled along three riparian corridors (Lewis Creek, Rugg Brook, and Rock River) to capture a broader range of parent material and P content. These samples were analyzed for particle size separates (sand, silt, and clay content), TP, and oxalate extractable P. Results showed a strong relationship between soil series variation (e.g., texture and drainage differences) and native P concentration. The first study revealed that both Modified Morgan extractable P and TP were lower in the coarser-textured, well drained soil series compared to the finer-textured soils. In the second study, native P concentrations (TP and oxalate extractable P) were also significantly greater in the finer-textured soils. The ratio of oxalate extractable P to TP decreased strongly with increasing sand content (r2 = 0.69), indicating that the finer-textured soils had a greater fraction of potentially desorbable P. Texture was a good indicator of native P concentrations across a wide range of soil properties, suggesting that accurate soil maps will be an important tool for indexing the native P status along riparian corridors in the Lake Champlain Basin region.

Litter decomposition can detect effects of high and moderate levels of forest disturbance on stream condition

Considerable research efforts have been devoted to determining what forest management practices most affect stream ecosystems, and how those impacts might be mitigated. Recent studies have stressed the relevance of litter decomposition to assess the conditions of headwater streams affected by riparian and upland forest harvest. Here we specifically examined whether litter decomposition can detect ecological effects of clearcutting to stream edges on headwater streams eight years after logging and if large (30 m) and narrow (10 m) riparian reserves (8-year post-harvest), and selection logging at 50% removal of basal area of riparian trees (1-year post-harvest), are effective protection measures for streams. We measured decomposition rates of red alder ( Alnus rubra) leaf litter in sixteen stream reaches, including reference reaches in a 70-year-old forest. We further examined assemblages of two main litter consumer groups, shredder invertebrates in riffles and aquatic hyphomycete fungi developing on decaying alder leaves. Alder decay rate was significantly lower in clearcut reaches than in reference reaches, and we found no evidence that any alternative riparian management practices examined in this study were able to mitigate against such an effect of logging. In unlogged reaches, rapid litter decomposition (0.0050–0.0118 day −1) was associated with high density and diversity of shredders (up to ten taxa). Slower litter decomposition in wide and narrow reserve reaches (0.0019–0.0054 day −1) and clearcut reaches (0.0024–0.0054 day −1) was attributed to lower density and richness of shredders. By contrast, the low decay rate in recently established thinned reaches (0.0031–0.0049 day −1) was not associated with a numerical response of shredders. Smothering of submerged leaves by sediments may have caused the reduction in alder decay rate in thinned reaches. Across all forest treatments fungal biomass or diversity remained fairly similar. Our findings suggest that stream ecosystems are extremely sensitive to small changes in riparian and upland forest cover. We propose that litter decomposition as a key ecosystem function in streams could be incorporated into further efforts to evaluate and improve forestry best management practices.

‘The sweeter country’: social dimensions to riparian management in the Burdekin rangelands, Queensland

In this article, we examine the social issues underpinning cattle producers' riparian management decisions in the savanna rangelands of north-eastern Queensland. Improved riparian management in these beef grazing regions has become increasingly important given the decline in water quality entering the Great Barrier Reef World Heritage Area. Consequently, there is pressure from management agencies on cattle producers to adopt recommended riparian management practices. However, little is known about what is driving cattle producers' riparian management choices and the factors influencing these choices. Interviews with producers from 18 properties in the Burdekin rangelands sought to fill this knowledge gap. Results showed that the decision by producers to adopt such riparian management practices as fencing and spelling of riparian pastures was largely based on the perceived production benefits and losses. However, an array of social, environmental and financial factors also influenced producers' riparian management decisions. Key influencing factors include social learning, position in the catchment, and financial capacity. Implications for future policy and extension programs are discussed.

Preferences for riparian buffers

Intensive management of riparian zones in the Mid-western United States has long involved clearing vegetation, straightening meandering streams, and lining earthen banks with stone or concrete. Recently, however, scholars have begun to document the ecological costs of such practices. Replacing barren stream edges with more natural alternatives such as vegetated buffers can improve the visual appeal, environmental services, and ecological health of these ecosystems. Despite their potential benefits, these alternatives are rarely employed. Is it because individual landowners dislike these management strategies or is it that professional planners disapprove of such options? This paper examines the approval of various riparian buffer types by landowners and planners in Illinois using a photo-questionnaire. Participants rated their preferences for tree buffers, grass buffers, and a ‘no buffer’ condition along waterways in rural and suburban landscapes. They also rated their preferences for meandering streams in rural areas and earthen banks in the suburbs. The results show substantial support for tree buffers by both residents and planners. Participants also demonstrated considerable approval for meandering streams in rural areas. These findings add to the growing body of literature on preferences for buffers in different landscape settings and provide ample evidence for planners and policy-makers to take necessary steps to preserve or restore vegetated riparian buffers and meandering channels along Mid-western waterways. These natural alternatives to existing strategies are not only visually attractive and ecologically beneficial, they are also positive steps towards more sustainable riparian management practices.

‘The sweeter country’: social dimensions to riparian management in the Burdekin rangelands, Queensland

In this article, we examine the social issues underpinning cattle producers' riparian management decisions in the savanna rangelands of north-eastern Queensland. Improved riparian management in these beef grazing regions has become increasingly important given the decline in water quality entering the Great Barrier Reef World Heritage Area. Consequently, there is pressure from management agencies on cattle producers to adopt recommended riparian management practices. However, little is known about what is driving cattle producers' riparian management choices and the factors influencing these choices. Interviews with producers from 18 properties in the Burdekin rangelands sought to fill this knowledge gap. Results showed that the decision by producers to adopt such riparian management practices as fencing and spelling of riparian pastures was largely based on the perceived production benefits and losses. However, an array of social, environmental and financial factors also influenced producers' riparian management decisions. Key influencing factors include social learning, position in the catchment, and financial capacity. Implications for future policy and extension programs are discussed.

MATURE AND OLD-GROWTH RIPARIAN FORESTS: STRUCTURE, DYNAMICS, AND EFFECTS ON ADIRONDACK STREAM HABITATS

Riparian forests regulate linkages between terrestrial and aquatic ecosystems, yet relationships among riparian forest development, stand structure, and stream habitats are poorly understood in many temperate deciduous forest systems. Our research has (1) described structural attributes associated with old-growth riparian forests and (2) assessed linkages between these characteristics and in-stream habitat structure. The 19 study sites were located along predominantly first- and second-order streams in northern hardwood-conifer forests in the Adirondack Mountains of New York (U.S.A.). Sites were classified as mature forest (6 sites), mature with remnant old-growth trees (3 sites), and old-growth (10 sites). Forest-structure attributes were measured over stream channels and at varying distances from each bank. In-stream habitat features such as large woody debris (LWD), pools, and boulders were measured in each stream reach. Forest structure was examined in relation to stand age using multivariate techniques, ANOVA, and linear regression. We investigated linkages between forest structure and stream characteristics using similar methods, preceded by information-theoretic modeling (AIC). Old-growth riparian forest structure is more complex than that found in mature forests and exhibits significantly greater accumulations of aboveground tree biomass, both living and dead. In-stream LWD volumes were significantly (alpha = 0.05) greater at old-growth sites (200 m3/ha) compared to mature sites (34 m3/ha) and were strongly related to the basal area of adjacent forests. In-stream large-log densities correlated strongly with debris-dam densities. AIC models that included large-log density, debris-dam density, boulder density, and bankfull width had the most support for predicting pool density. There were higher proportions of LWD-formed pools relative to boulder-formed pools at old-growth sites as compared to mature sites. Old-growth riparian forests provide in-stream habitat features that have not been widely recognized in eastern North America, representing a potential benefit from late-successional riparian forest management and conservation. Riparian management practices (including buffer delineation and restorative silvicultural approaches) that emphasize development and maintenance of late-successional characteristics are recommended where the associated in-stream effects are desired.

SEDIMENT TRANSPORT AND CHANNEL MORPHOLOGY OF SMALL, FORESTED STREAMS

This paper reviews sediment transport and channel morphology in small, forested streams in the Pacific Northwest region of North America to assess current knowledge of channel stability and morphology relevant to riparian management practices around small streams. Small channels are defined as ones in which morphology and hydraulics may be significantly influenced by individual clasts or wood materials in the channel. Such channels are headwater channels in close proximity to sediment sources, so they reflect a mix of hillslope and channel processes. Sediment inputs are derived directly from adjacent hillslopes and from the channel banks. Morphologically significant sediments move mainly as bed load, mainly at low intensity, and there is no standard method for measurement. The larger clastic and woody elements in the channel form persistent structures that trap significant volumes of sediment, reducing sediment transport in the short term and substantially increasing channel stability. The presence of such structures makes modeling of sediment flux in these channels — a potential substitute for measurement — difficult. Channel morphology is discussed, with some emphasis on wood related features. The problem of classifying small channels is reviewed, and it is recognized that useful classifications are purpose oriented. Reach scale and channel unit scale morphologies are categorized. A “disturbance cascade” is introduced to focus attention on sediment transfers through the slope channel system and to identify management practices that affect sediment dynamics and consequent channel morphology. Gaps in knowledge, errors, and uncertainties have been identified for future research.

SEDIMENT TRANSPORT AND CHANNEL MORPHOLOGY OF SMALL, FORESTED STREAMS

This paper reviews sediment transport and channel morphology in small, forested streams in the Pacific Northwest region of North America to assess current knowledge of channel stability and morphology relevant to riparian management practices around small streams. Small channels are defined as ones in which morphology and hydraulics may be significantly influenced by individual clasts or wood materials in the channel. Such channels are headwater channels in close proximity to sediment sources, so they reflect a mix of hillslope and channel processes. Sediment inputs are derived directly from adjacent hillslopes and from the channel banks. Morphologically significant sediments move mainly as bed load, mainly at low intensity, and there is no standard method for measurement. The larger clastic and woody elements in the channel form persistent structures that trap significant volumes of sediment, reducing sediment transport in the short term and substantially increasing channel stability. The presence of such structures makes modeling of sediment flux in these channels — a potential substitute for measurement — difficult. Channel morphology is discussed, with some emphasis on wood related features. The problem of classifying small channels is reviewed, and it is recognized that useful classifications are purpose oriented. Reach scale and channel unit scale morphologies are categorized. A “disturbance cascade” is introduced to focus attention on sediment transfers through the slope channel system and to identify management practices that affect sediment dynamics and consequent channel morphology. Gaps in knowledge, errors, and uncertainties have been identified for future research.