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Ecosystem management and governance of cross-scale dependent systems require integrating knowledge about ecological connectivity in its multiple forms and scales. Although scientists, managers, and policymakers are increasingly recognizing the importance of connectivity, governmental organizations may not be currently equipped to manage ecosystems with strong cross-boundary dependencies. Managing the different aspects of connectivity requires building social connectivity to increase the flow of information, as well as the capacity to coordinate planning, funding, and actions among both formal and informal governance bodies. We use estuaries in particular the San Francisco Estuary, in California, in the United States, as examples of cross-scale dependent systems affected by many intertwined aspects of connectivity. We describe the different types of estuarine connectivity observed in both natural and human-affected states and discuss the human dimensions of restoring beneficial physical and ecological processes. Finally, we provide recommendations for policy, practice, and research on how to restore functional connectivity to estuaries.

Agriculture is the largest single source of environmental degradation, responsible for over 30% of global greenhouse gas (GHG) emissions, 70% of freshwater use and 80% of land conversion: it is the single largest driver of biodiversity loss (Foley JA, Science 309:570–574, 2005, Nature 478:337–342, 2011; IPBES. Global assessment report on biodiversity and ecosystem services of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services. IPBES Secretariat, Bonn, 2019; Willett W et al. The Lancet 393:447–492, 2019). Agriculture also underpins poor human health, contributing to 11 million premature deaths annually. While too many still struggle from acute hunger, a growing number of individuals, including in low to middle-income countries (LMICs), struggle to access healthy foods. Greater consideration for, and integration of, biodiversity in agriculture is a key solution space for improving health, eliminating hunger and achieving nature-positive development objectives.This rapid evidence review documents the best available evidence of agriculture’s relationships with biodiversity, drawing on the contributions of leading biodiversity experts, and recommends actions that can be taken to move towards more biodiversity/nature-positive production through the delivery of integrated agricultural solutions for climate, biodiversity, nutrition and livelihoods. The analysis, which takes a whole-of-food-system approach, brings together a large body of evidence. It accounts for aspects not typically captured in a stand-alone primary piece of research and indicates where there are critical gaps.

Timely, policy-relevant monitoring data are essential for evaluating the effectiveness of environmental policies and conservation measures. Satellite and aerial imagery can fill data gaps at low cost but are often underused for ongoing environmental monitoring. Barriers include a lack of expertise or computational resources and the lag time between image acquisition and information delivery. Online image repositories and cloud computing platforms are increasingly used by researchers because they offer near-real-time, centralized access to local-to-global-scale data sets and analytics with minimal in-house computational requirements. We aim to broaden knowledge of these open access resources for biologists whose work routinely informs policy and management. To illustrate potential applications of cloud-based environmental monitoring (CBEM), we developed an adaptable approach to detect changes in natural vegetative cover in an agricultural watershed. The steps we describe can be applied to identify opportunities and caveats for applying CBEM in a wide variety of monitoring programs.

Wildlife corridors aim to promote species' persistence by connecting habitat patches across fragmented landscapes. Their implementation is limited by patterns of land ownership and complicated by differences in the jurisdictional and regulatory authorities under which lands are managed. Terrestrial corridor conservation requires coordination across jurisdictions and sectors subject to site-specific overlapping sources of legal authority. Mapping spatial patterns of legal authority concurrent with habitat condition can illustrate opportunities to build or leverage capacity for connectivity conservation. Streamside areas provide pragmatic opportunities to leverage existing policy mechanisms for riverine and terrestrial habitat connectivity across boundaries. Conservation planners and practitioners can make use of these opportunities by harmonizing actions for multiple conservation outcomes. We formulated an integrative, data-driven method for mapping multiple sources of legal authority weighted by capacity for coordinating terrestrial habitat conservation along streams. We generated a map of capacity to coordinate streamside corridor protections across a wildlife habitat gap to demonstrate this approach. We combined values representing coordination capacity and naturalness to generate an integrated legal-ecological resistance map for connectivity modeling. We then computed least-cost corridors across the integrated map, masking the terrestrial landscape to focus on streamside areas. Streamside least-cost corridors in the integrated, local-scale model diverged (∼25 km) from national-scale least-cost corridors based on naturalness. Spatial categories comparing legal- and naturalness-based resistance values by stream reach highlighted potential locations for building or leveraging existing capacity through spatial coordination of policy mechanisms or restoration actions. Agencies or nongovernmental organizations intending to restore or maintain habitat connectivity across fragmented landscapes can use this approach to inform spatial prioritization and build coordination capacity. Article impact statement: Combined mapping of legal authority and habitat condition reveals capacity to coordinate actions along streams for clean water and wildlife.Mapeo de la Autoridad Legal para los Corredores Terrestres de Conservación a lo Largo de Ríos Stahl et al. Resumen Los corredores de fauna buscan promover la persistencia de las especies al conectar los fragmentos de hábitat a lo largo de paisajes fragmentados. Su implementación está limitada por los patrones de propiedad de tierras y se complica con las diferencias entre las autoridades jurisdiccionales y regulatorias que las administran. La conservación por corredores terrestres requiere de coordinación entre las jurisdicciones y los sectores sujetos a fuentes de autoridad legal que se traslapan y que son específicas del sitio. El mapeo de los patrones espaciales de la autoridad legal simultánea a la condición del hábitat puede ilustrar oportunidades para construir o hacer uso de la capacidad para la conservación por conectividad. Las áreas adyacentes a los cauces fluviales proporcionan oportunidades prácticas para hacer uso de los mecanismos políticos existentes para la conectividad de hábitats ribereño y terrestre a través de las fronteras. Los planificadores y practicantes de la conservación pueden usar estas oportunidades al armonizar las acciones para múltiples resultados de conservación. Formulamos un método integrativo orientado por los datos para mapear las múltiples fuentes de autoridad legal ponderadas por la capacidad para coordinar la conservación de hábitats terrestres a lo largo de ríos. Generamos un mapa de la capacidad para coordinar los corredores de protección a lo largo de los vacíos en los hábitats de fauna para demostrar esta estrategia. Combinamos los valores por medio de la representación de la capacidad de coordinación y la naturalidad para generar un mapa de resistencia legal y ecológica para el modelado de la conectividad. Después, computamos los corredores de menor costo en todo el mapa integrado, enmascarando el paisaje terrestre para enfocarnos en las áreas adyacentes al cauce fluvial. Los corredores de menor costo adyacentes a los cauces dentro del modelo integrado de escala local difirieron (∼25 km) de los corredores de menor costo basados en la naturalidad a escala nacional. Las categorías espaciales que compararon los valores de resistencia basada en la legalidad y en la naturalidad por alcance del río resaltaron las localidades potenciales para la construcción o el uso de la capacidad existente por medio de la coordinación espacial de los mecanismos de política o de las acciones de restauración. Las agencias y organizaciones no gubernamentales con la intención de restaurar o mantener la conectividad del hábitat en un paisaje fragmentado pueden utilizar esta estrategia para informar la priorización espacial y construir la capacidad de coordinación.野生动物廊道旨在通过连接破碎景观中的栖息地斑块来提高物种的续存, 但其建设受限于土地所有制模式, 还会因管理土地的管辖及监管机构不同而更加复杂。陆地廊道保护需要多个司法管辖区和各地受到多种法定权威管制的部门之间的协调。将法定权威的空间格局与栖息地条件的分布地图相叠加, 将有利于开展廊道连接度保护的能力建设及利用。河流沿岸地区为现有的跨境河流及陆地栖息地连接度的相关政策机制的应用提供了实践机会。保护规划者和实施者可以利用这些机会协调多方行动以取得各方面的保护成效。我们制定了一个综合的、基于数据驱动的方法, 可以将协调河流沿岸陆地栖息地保护的能力作为权重来绘制多个法定权威来源的地图。为了演示这个方法, 我们绘制了一张协调跨越野生动物栖息地空缺地带的河流沿岸廊道保护力地图。我们将代表协调能力和自然特性的数值相结合, 生成了一张用于连接度建模的法律-生态抵抗力综合地图。随后, 我们忽略陆地景观, 将重点放在河流沿岸地区, 计算了整个综合地图的最低成本廊道。结果显示, 由局部尺度的综合模型得到的河流沿岸最低成本廊道与基于自然特性的国家尺度最低成本廊道偏离约 25 公里。河流沿岸基于法律和自然特性抵抗力比较的空间分类进一步展示了可以通过政策机制或恢复行动的空间协调来建设和利用现有能力的潜在地点。计划恢复或维持破碎景观之间的栖息地连接度的机构或非政府组织可以应用这种方法确定优先保护的空间并建立协调力。【翻译: 胡怡思; 审校: 聂永刚】.

Setting clear biodiversity targets is a pervasive challenge1 due to the context-dependent nature of biodiversity that has evaded concise science-based objectives such as the 1.5°C for climate2. Considering the major risk of continued inaction, and further biodiversity loss, it is imperative that the biodiversity community identify similarly operational science-based boundaries supporting the development of targets to safeguard biodiversity and its contributions to human well-being. Confounding goal setting are the two distinct but not mutually exclusive conservation objectives: (1) halting the rampant loss of intact ecosystems, species extinction and population declines, and (2) maintaining biosphere integrity and ecosystem function. We propose a revised planetary boundary for biodiversity: retaining at least half of the area of each terrestrial ecoregion biologically intact to halt the extinction crisis, and maintaining ecosystem integrity across all lands to preserve and regenerate biosphere, ecosystem functions and their contributions to human well-being. We combine four intactness datasets to provide a global assessment and find that 49.6% of the Earth’s land ice-free surface remains intact. While this is promising globally, 69% of 798 unique ecoregions are less than half intact. For ecosystem integrity, we find 18.1% of working lands have ecosystem integrity deficits precluding the provisioning of biosphere and ecosystem functions. Ninety percent of ecoregions have an ecosystem integrity deficit. Globally, intactness and integrity are at boundary limits with degradation of nature critically jeopardizing biosphere capacity to support a safe and just space for humanity. Combined efforts are needed to halt loss of and restore intactness, while regenerating integrity in working lands.

In the management of natural resources, scale mismatch occurs when resources are not managed at the spatial or temporal scale at which they are provisioned. Issues of scale mismatch abound in social–ecological systems and can hinder efforts to effectively manage resources, threaten the resilience of the larger ecosystem, and affect societal well-being and livelihoods. Here, we provide a brief overview of the scale mismatch literature and discuss potential opportunities to address scale mismatches in drinking water management. We present a case study of spring water management in rural communities in the Cartago province of Costa Rica, where community groups face issues of both spatial and temporal mismatch in providing drinking water to their users. Through this case study, we observed that issues of scale mismatch are often overlooked because of a lack of understanding of the scale at which resources are sustained. We argue that highlighting examples of scale mismatch will help others to identify and understand their own systems and be better prepared to reconfigure operations to govern and manage social–ecological systems. Given the dynamic, adaptive nature of social–ecological systems, scale dependencies can change in a system. Thus, we recommend periodic scale mismatch analysis in these systems.

Achieving well-being for all, while protecting the environment, is one of the most pressing global challenges of our time, and a central idea in the UN Sustainable Development Goals (SDGs). We believe that integrating ecosystem services, the benefits nature provides to people, into strategies for meeting the SDGs can help achieve this. Many development goals are likely underpinned by the delivery of one or more ecosystem services. Understanding how these services could support multiple development targets will be essential for planning synergistic and cost-effective interventions. Here we present the results of an expert survey on the contributions of 16 ecosystem services to achieving SDG targets linked to environment and human well-being, and review the capacity of modelling tools to evaluate SDG-relevant ecosystem services interactions. Survey respondents judged that individual ecosystem services could make important contributions to achieving 41 targets across 12 SDGs. The provision of food and water, habitat & biodiversity maintenance, and carbon storage & sequestration were perceived to each make contributions to >14 SDG targets, suggesting cross-target interactions are likely, and may present opportunities for synergistic outcomes across multiple SDGs. Existing modelling tools are well-aligned to support SDG-relevant ecosystem service planning. Together, this work identifies entry points and tools to further analyze the role of ecosystem services to support the SDGs.

Summary Temperate ectomycorrhizal (ECM) fungi show segregation whereby some species dominate in organic layers and others favor mineral soils. Weak layering in tropical soils is hypothesized to decrease niche space and therefore reduce the diversity of ectomycorrhizal fungi. The Neotropical ECM tree Dicymbe corymbosa forms monodominant stands and has a distinct physiognomy with vertical crown development, adventitious roots and massive root mounds, leading to multi-stemmed trees with spatially segregated rooting environments: aerial litter caches, aerial decayed wood, organic root mounds and mineral soil. We hypothesized that these microhabitats host distinct fungal assemblages and therefore promote diversity. To test our hypothesis, we sampled D. corymbosa ectomycorrhizal root tips from the four microhabitats and analyzed community composition based on pyrosequencing of fungal internal transcribed spacer (ITS) barcode markers. Several dominant fungi were ubiquitous but analyses nonetheless suggested that communities in mineral soil samples were statistically distinct from communities in organic microhabitats. These data indicate that distinctive rooting zones of D. corymbosa contribute to spatial segregation of the fungal community and likely enhance fungal diversity.

The production and respiration of organic carbon in streams (stream metabolism) is a fundamental ecosystem process. The extent to which the magnitude of stream metabolism changes with forest conversion to agriculture in humid tropical headwaters is poorly understood. We measured whole-stream metabolism in headwaters draining forest-agricultural boundaries to investigate metabolic rates in areas with abrupt land-use transitions and the role of remnant riparian vegetation. We used linear mixed models to test the hypotheses that gross primary production (GPP) and ecosystem respiration (ER) would be higher in agricultural areas due to higher light availability and nutrient concentrations, respectively. We found a 257% increase in GPP and 30% increase in ER in agricultural stream reaches. GPP was driven by light and ER was mainly controlled by GPP. These results highlight the overriding influence of light in agricultural streams with large fractions of upstream forest cover. Our findings suggest that high riparian canopy cover (~90%) is necessary to support stream metabolic rates similar to forests in agricultural areas. This study adds to our understanding of the within-biome variation of metabolism resulting from agriculture, and the potential similarities between forested biomes and the role of tropical streams in the global carbon cycle.

Ecosystem service-support tools are commonly used to guide natural resource management. Often, empirically based models are preferred due to low data requirements, simplicity and clarity. Yet, uncertainty produced by local context or parameter estimation remains poorly quantified and documented. We assessed model uncertainty of the Revised Universal Soil Loss Equation – RUSLE developed mainly from US data. RUSLE is the most commonly applied model to assess watershed-level soil loss. We performed a global sensitivity analysis (GSA) on RUSLE with four dissimilar datasets to understand uncertainty and to provide recommendations for data collection and model parameterization. The datasets cover varying spatial levels (plot, watershed and continental) and environmental conditions (temperate and tropical). We found cover management and topography create the most uncertainty regardless of environmental conditions or data parameterization techniques. The importance of other RUSLE factors varies across contexts. We argue that model uncertainty could be reduced through better parameterization of cover management and topography factors while avoiding severe soil losses by targeting soil conservation practices in areas where both factors interact and enhance soil loss. We recommend incorporating GSA to assess empirical models’ uncertainty, to guide model parameterization and to target soil conservation efforts.EDITED BY Rob Alkemade EDITED BY Rob Alkemade

The DNA of aquatic organisms can be identified in water sampled from freshwater ecosystems to detect species presence. Because these DNA-based methods (termed environmental DNA, eDNA) confirm species presence by proxy of DNA in water, the processes influencing eDNA transport and removal from water are critical to the method's efficacy and interpretation of results. Previous studies of aquatic eDNA transport and fate have employed uncontrolled field experiments, controlled studies in experimental streams, and laboratory column tests. As a step toward understanding the processes controlling eDNA transport and retention, we released and tracked experimental pulses of white sturgeon eDNA (novel to the system) in five fourth-order stream reaches with varied hydrology and geomorphology. We found strong support that stream water transient storage controls eDNA areal uptake rate (or spiraling length). We calculated the median spiraling length to be ∼260 m. Down channel slope correlated with transient storage, suggesting that this slope could be used as a proximate measure of eDNA removal into the benthic zone. Our results suggest that sampling effort should be increased in reaches with longer transient storage (or lower slopes) to compensate for the increase in eDNA retention.

Quantifying the spatial and temporal dynamics of stream metabolism across stream networks is key to understanding carbon cycling and stream food web ecology. To better understand intra-annual temporal patterns of gross primary production (GPP) and ecosystem respiration (ER) and their variability across space, we continuously measured dissolved oxygen and modeled stream metabolism for an entire year at ten sites across a temperate river network in Washington State, USA. We expected GPP and ER to increase with stream size and peak during summer and autumn months due to warmer temperatures and higher light availability. We found that GPP and ER increased with drainage area and that only four sites adhered to our expectations of summer peaks in GPP and autumn peaks in ER while the rest either peaked in winter, spring or remained relatively constant. Our results suggest the spatial arrangement and temporal patterns of discharge, temperature, light and nutrients within watersheds may result in asynchronies in GPP and ER, despite similar regional climatic conditions. These findings shed light on how temporal dynamics of stream metabolism can shift across a river network, which likely influence the dynamics of carbon cycling and stream food webs at larger scales.

Ecosystem service‐based management requires an accurate understanding of how human modification influences ecosystem processes and these relationships are most accurate when based on functional traits. Although trait variation is typically sampled at local scales, remote sensing methods can facilitate scaling up trait variation to regional scales needed for ecosystem service management. We review concepts and methods for scaling up plant and animal functional traits from local to regional spatial scales with the goal of assessing impacts of human modification on ecosystem processes and services. We focus our objectives on considerations and approaches for (1) conducting local plot‐level sampling of trait variation and (2) scaling up trait variation to regional spatial scales using remotely sensed data. We show that sampling methods for scaling up traits need to account for the modification of trait variation due to land cover change and species introductions. Sampling intraspecific variation, stratification by land cover type or landscape context, or inference of traits from published sources may be necessary depending on the traits of interest. Passive and active remote sensing are useful for mapping plant phenological, chemical, and structural traits. Combining these methods can significantly improve their capacity for mapping plant trait variation. These methods can also be used to map landscape and vegetation structure in order to infer animal trait variation. Due to high context dependency, relationships between trait variation and remotely sensed data are not directly transferable across regions. We end our review with a brief synthesis of issues to consider and outlook for the development of these approaches. Research that relates typical functional trait metrics, such as the community‐weighted mean, with remote sensing data and that relates variation in traits that cannot be remotely sensed to other proxies is needed. Our review narrows the gap between functional trait and remote sensing methods for ecosystem service management.

Adaptive governance must work "on the ground," that is, it must operate through structures and procedures that the people it governs perceive to be legitimate and fair, as well as incorporating processes and substantive goals that are effective in allowing social-ecological systems (SESs) to adapt to climate change and other impacts. To address the continuing and accelerating alterations that climate change is bringing to SESs, adaptive governance generally will require more flexibility than prior governance institutions have often allowed. However, to function as good governance, adaptive governance must pay real attention to the problem of how to balance this increased need for flexibility with continuing governance stability so that it can foster adaptation to change without being perceived or experienced as perpetually destabilizing, disruptive, and unfair. Flexibility and stability serve different purposes in governance, and a variety of tools exist to strike different balances between them while still preserving the governance institution's legitimacy among the people governed. After reviewing those purposes and the implications of climate change for environmental governance, we examine psychological insights into the structuring of adaptive governance and the variety of legal tools available to incorporate those insights into adaptive governance regimes. Because the substantive goals of governance systems will differ among specific systems, we do not purport to comment on what the normative or substantive goals of law should be. Instead, we conclude that attention to process and procedure (including participation), as well as increased use of substantive standards (instead of rules), may allow an increased level of substantive flexibility to operate with legitimacy and fairness, providing the requisite levels of psychological, social, and economic stability needed for communities to adapt successfully to the Anthropocene.

The Columbia River is a complex water basin shared by 2 countries, 15 Native American Tribes, 15 First Nations, 7 US states, and 1 Canadian province. Dam construction during the twentieth century has engendered a basin economy that is dependent on low-cost electricity and irrigated agriculture. Yet, these dams are a major factor in the decline of populations of salmon and steelhead species that are critical to the culture of Indigenous peoples. Climate change scenarios predict a transformation from snow- to rain-dominated precipitation in the basin’s lower latitudes, greater extremes in flood and drought, and an increasing water deficit as a result of higher rates of evapotranspiration with increasing temperature. Reduced late summer flow may pose challenges for the sustainability of irrigation and fish. The basin provides a unique laboratory to explore resilience of a highly developed social-ecological system to changing climate and rising empowerment of Indigenous peoples. Review of the Columbia River Treaty between the United States and Canada that governs much of the operation of the river presents a window of opportunity for change. This window provides a moment in time to rethink environmental governance and to consider an approach which reflects neither top-down nor bottom-up control of resources but a third path in which each level of government plays a supporting role to a regional vision of the basin’s future governance.

The detection of rare macroorganisms using environmental DNA (eDNA) is a powerful new method for conservation and management; the efficacy of this method is affected by physiological, ecological, and hydrological processes. Understanding the processes limiting eDNA detection and accounting for those factors with optimized sampling designs is critical for realizing the potential of this tool. Amphibians are a focus of conservation programs globally and are often difficult to detect, presenting a challenge for effective action. To increase the ability of eDNA techniques to inform conservation and management programs, we investigated the eDNA detection of amphibians compared with field surveys for six species across a gradient of environmental factors expected to affect eDNA detection in three different systems: perennial wetlands, intermittent wetlands, and acidic intermittent wetlands. We applied a baseline sampling design in each wetland and used an occupancy modeling approach to evaluate evidence for processes limiting detection for each species given the presence of the target species. Evidence weights indicated that limiting processes varied across systems and included those associated with increased degradation (pH 25 °C) and limited dispersion (wetland area > 1200 m2, sample volume

Salmon that spawn in streams deliver marine-derived nutrients (MDN) that catalyze trophic productivity and support rearing juvenile salmon. Salmon spawning also affects hyporheic exchange and movement of dissolved MDN through the stream bed by creating redd topography that induces pumping exchange and by winnowing fine sediment and loosening the bed, which alters hydraulic conductivity and bed porosity. The spatial extent of spawning within the channel likely governs the volume and rate of dissolved MDN exchanged with the stream bed through this process. To explore this issue, we used a two-dimensional groundwater model to predict changes in hyporheic volume, flux, and mean hydraulic residence time of dissolved MDN as a function of the proportion of the bed surface occupied by redds (P). Predictions indicate that hyporheic volume and flux systematically increase with P, while the mean hydraulic residence time of dissolved MDN in the hyporheic zone decreases sharply with P, from 5.79 h on an unspawned bed (P = 0) to 0.03 h for a mass-spawned bed (P = 1.0). Shorter residence time results from hyporheic flux increasing faster than hyporheic volume with higher P. Implications for uptake of dissolved MDN are explored with Damköhler numbers, defined as the ratio of the mean hydraulic residence time to a biogeochemical rate of interest. Given the considerable influence of spawning on hyporheic exchange, additional research is needed to determine conditions under which bioassimilation of dissolved MDN is limited by nutrient supply, extent of the hyporheic zone, or processing rate of MDN in stream beds.

Where female salmon build nests (“redds”), streambed material is mixed, fine sediment is winnowed, and bed material is moved into a tailspill mound resembling the shape of a dune. Completed redd surfaces are coarser and better sorted than unspawned beds, which is thought to increase redd stability because larger grains are heavier and harder to move, and sorting increases friction angles for mobility. However, spawning also loosens sediment and creates topography that accelerates flow, which can increase particle mobility. We address these factors controlling the relative stability of redds and unspawned beds in flume experiments where redds were constructed with a technique that mimics the nesting behavior of female salmon. Although redds exhibited relatively coarse surfaces, measured entrainment forces indicate particle loosening by spawning lowered grain resistance to motion by 12-37% on average compared to unspawned beds. In addition, for the same discharges, boundary shear stress was 13-41% higher on a redd due to flow convergence on the tailspill. Visual measurements of particle entrainment further indicated redd instability, as bed average shear stress was 22% lower at incipient motion and 29% lower at the discharge that mobilized all grain sizes on a redd. Overall, results demonstrate redds are unstable compared to unspawned beds, which increases the risk of scour for buried eggs, but may facilitate fine-sediment flushing and improve the quality of spawning gravels for future generations of spawners. Therefore, managing salmon returns to increase streambed disturbance may be an effective tool for reducing sedimentation impacts on salmon reproduction. This article is protected by copyright. All rights reserved.

Whether or not reservoirs contain water throughout the dry season is critical to avoiding late season crop failure in seasonally-arid agricultural landscapes. Locations, volumes, and temporal dynamics, particularly of small (

SUMMARY 1. In stream ecosystems, Pacific salmon deliver subsidies of marine-derived nutrients and disturb the stream bed during spawning. The net effect of this nutrient subsidy and physical disturbance on biological communities can be hard to predict and is likely to be mediated by environmental conditions. For periphyton, empirical studies have revealed that the magnitude and direction of the response to salmon varies from one location to the next. Salmon appear to increase periphyton biomass and/or production in some contexts (a positive response), but decrease them in others (a negative response). 2. To reconcile these seemingly conflicting results, we constructed a system dynamics model that links periphyton biomass and production to salmon spawning. We used this model to explore how environmental conditions influence the periphyton response to salmon. 3. Our simulations suggest that the periphyton response to salmon is strongly mediated by both background nutrient concentrations and the proportion of the stream bed suitable for spawning. Positive periphyton responses occurred when both background nutrient concentrations were low (nutrient limiting conditions) and when little of the stream bed was suitable for spawning (because the substratum is too coarse). In contrast, negative responses occurred when nutrient concentrations were higher or a larger proportion of the bed was suitable for spawning. 4. Although periphyton biomass generally remained above or below background conditions for several months following spawning, periphyton production returned quickly to background values shortly afterwards. As a result, based upon our simulations, salmon did not greatly increase or decrease overall annual periphyton production. This suggests that any increase in production by fish or invertebrates in response to returning salmon is more likely to occur via direct consumption of salmon carcasses and/or eggs, rather than the indirect effects of greater periphyton production. 5. Overall, our simulations suggest that environmental factors need to be taken into account when considering the effects of spawning salmon on aquatic ecosystems. Our model offers researchers a framework for testing periphyton response to salmon across a range of conditions, which can be used to generate hypotheses, plan field experiments and guide data collection.

Recent advances in using naturally occurring isotopes to reconstruct movement patterns have revolutionized the study of migration and spatial patterns across taxa. Isoscape approaches utilize isotopic variation in the underlying geology to quantify migration pathways. Spatial patterns in the geology can be used to predict isotopic variation, such as 87Sr/86Sr; however, previous attempts to create predictive models have had mixed results. Our primary objective was to investigate the relationship between bedrock lithology and 87Sr/86Sr ratio as a tool to extend the spatial resolution of animal migration studies. Secondly, we investigated the ability to use geologic prediction as an a priori tool for determining chemically distinct watersheds. We first developed a regression model to relate known stream water 87Sr/86Sr to rock information from geologic maps, then used model outputs to classify adult fall Chinook salmon to their juvenile rearing location from 87Sr/86Sr signatures recorded in their otoliths (ear bones). We discuss the effect of scale and geologic heterogeneity on our ability to determine 87Sr/86Sr ratios within the study area. Our results indicate that the relationship between 87Sr/86Sr values and bedrock lithology can be used to accurately determine the rearing location of fish using otolith 87Sr/86Sr signatures. The scale at which geology can be used as a predictor of 87Sr/86Sr values is constrained by geologic heterogeneity and inherent variability in 87Sr/86Sr ratios within major rock categories. Further, our results indicate that geological data alone can be used to quantitatively investigate which watersheds are likely to be distinguishable using this method within a basin. Geologic prediction also has the potential to improve the scale and resolution of isotopic studies and the development of isoscapes. By applying measures of spatial heterogeneity we will be better able to quantitatively place limits on the accuracy of geologic predictions of 87Sr/86Sr ratios.

Ecosystem-service production is strongly influenced by the landscape configuration of natural and human systems. Ecosystem services are not only produced and consumed locally but can be transferred within and among ecosystems. The time and distance between the producer and the consumer of ecosystem services can be considered lags in ecosystem-service provisioning. Incorporation of heterogeneity and lag effects into conservation incentives helps identify appropriate governance systems and incentive mechanisms for effective ecosystem-service management. These spatiotemporal dimensions are particularly apparent in river—riparian systems, which provide a suite of important ecosystem services and promote biodiversity conservation at multiple scales, including habitat protection and functional connectivity. Management of ecosystem services with spatiotemporal lags requires an interdisciplinary consideration of both the biophysical landscape features that produce services and the human actors that control and be...

Review of the Columbia River Treaty between the United States and Canada presents an opportunity to consider how governance might be made more adaptive in the face of climate change while maintaining an appropriate level of stability. Climate change scenarios applied to the Columbia River Basin predict an increasing water deficit due primarily to change in timing of runoff and increased demand as the result of warming. Current uses that will suffer the most from change in timing of runoff are those dependent on late summer flow – fish and farmers. The intersection of climate change with normal climate variability also suggests greater extremes that will require planning for both drought and flood beyond the historic recurrence and magnitude. A problem-solving approach to bridge the gap between the status quo and a modernized system must be combined with new approaches to governance that are both more flexible and more responsive to change if the basin is to navigate the future. This challenges not only the conventional wisdom that regulatory stability is essential to economic stability and achievement of societal goals, but the existing distribution of benefits among powerful players in the basin. Yet the goals of even the current recipients of benefits will not be met if a rigid approach is maintained as climate change unfolds. Adaptive water governance requires attention to institutional structure, introduction of adaptive authority and local participatory capacity including knowledge building, and process design that balances stability with flexibility. Models for implementation of these factors are found in international law and provide a pathway to adaptation to climate change through a modernized transboundary water agreement on the Columbia River.

Sustainable Development Goals offer an opportunity to improve human well-being while conserving natural resources. Ecosystem services highlight human well-being benefits ecosystems, including agricultural ecosystems, provides. Whereas agricultural systems produce the majority of our food, they drive significant environmental degradation. This tension between development and environmental conservation objectives is not an immutable outcome as agricultural systems are simultaneously dependents, and providers of ecosystem services. Recognizing this duality allows integration of environmental and development objectives and leverages agricultural ecosystem services for achieving sustainability targets. We propose a framework to operationalize ecosystem services and resilience-based interventions in agricultural landscapes and call for renewed efforts to apply resilience-based approaches to landscape management challenges and for refocusing ecosystem service research on human well-being outcomes.

Summary • The ectomycorrhizal (ECM) symbiosis was historically considered restricted to the temperate zones, but recent studies have shown the importance of this symbiosis across the tropics. We examined ECM fungal diversity, host plant phylogeny and ECM host preferences in a rainforest dominated by the leguminous host plants Dicymbe corymbosa, Dicymbe altsonii and Aldina insignis. • Ectomycorrhizal fungi were identified by internal transcribed spacer rDNA sequencing and host species were verified with chloroplast trnL sequencing. To test whether Dicymbe and Aldina represent independent gains of the ECM symbiosis, we constructed a Fabaceae phylogeny using MatK and trnL. We identified four independent ECM lineages within the Fabaceae. • We detected a diverse community of 118 ECM species dominated by the ⁄ clavulina, ⁄ russula-lactarius, ⁄ boletus, and ⁄ tomentella-thelephora lineages. Ectomycorrhizal species in Agaricales, Atheliales and Polyporales may represent previously unrecognized tropical-endemic ECM lineages. Previous studies suggested that ECM fungi did not diversify in the tropics, but the ⁄ clavulina lineage appears to have a center of diversity in tropical South America. • Dicymbe and Aldina represent independent gains of the ECM symbiosis in Fabaceae but their fungal symbionts showed no host preferences. Spatial factors are more important than hosts in structuring the ECM fungal community in this ecosystem.

In disturbance-prone ecosystems, organisms often persist in spatial refugia during stressful periods. A clear example is the colonization of abandoned river channels by pioneer riparian trees. Here, we examine the prominence of this establishment pathway for a foundation tree species (Fremont cottonwood, Populus fremontii) within the riparian corridor of a large river, the Sacramento River in central California. We quantified the total proportion of forest that initiated as a result of channel abandonment for a 160-km reach, analyzed concurrent patterns of tree establishment with floodplain accretion and sedimentation history, and developed a conceptual model of biogeomorphic evolution of abandoned channels. Historical air photo analysis indicated that stands associated with abandoned channels comprised more than 50% of the total extant cottonwood forest area. Tree-ring evidence showed that cottonwood stands commonly developed immediately following abandonment, and the recruitment window ranged from 4 to 40 years, but was less than 10 years at most sites. Rates of floodplain rise and fine sediment accumulation were high in young sites and decreased logarithmically over time. Together, these results suggest that abandoned channels are an important refuge for cottonwood recruitment, that the greatest opportunity for colonization occurs within a short period after the cutoff event, and that sedimentation processes influence the duration of the colonization window. On rivers where tree recruitment along the active channel is severely limited by hydrologic regulation and/or land management, abandoned channel refugia may play an even more important role in sustaining an ecologically functional riparian corridor. Preserving bank erosion, active meander corridors and forest regeneration zones created by cutoff events are therefore key conservation measures on shifting rivers.

Planning riparian restoration to resemble historic reference conditions requires an understanding of both local and regional patterns of plant species diversity. Thus, understanding species distributions at multiple spatial scales is essential to improve restoration planting success, to enhance long-term ecosystem functioning, and to match restoration planting designs with historic biogeographic distributions. To inform restoration planning, we examined the biogeographic patterns of riparian plant diversity at local and regional scales within a major western U.S.A. drainage, California's Sacramento-San Joaquin Valley. We analyzed patterns of species richness and complementarity (β-diversity) across two scales: the watershed scale and the floodplain scale. At the watershed scale, spatial patterns of native riparian richness were driven by herbaceous species, whereas woody species were largely cosmopolitan across the nearly 38,000 km 2 study area. At the floodplain scale, riparian floras reflected species richness and dissimilarity patterns related to hydrological and disturbance-driven successional sequences. These findings reinforce the importance of concurrently evaluating both local and regional processes that promote species diversity and distribution of native riparian flora. Furthermore, as restoration activities become more prevalent across the landscape, strategies for restoration outcomes should emulate the patterns of species diversity and biogeographic distributions found at regional scales. © 2011 Society for Ecological Restoration International.

Quantifying the influence of the landscape on the genetic structure of natural populations remains an important empirical challenge, particularly for poorly studied, ecologically cryptic species. We conducted an extensive microsatellite analysis to examine the population genetics of the southern long-toed salamander (Ambystoma macrodactylum sigillatum) in a naturally complex landscape. Using spatially explicit modelling, we investigated the influence of the Sierra Nevada topography on potential dispersal corridors between sampled populations. Our results indicate very high-genetic divergence among populations, high within-deme relatedness, and little evidence of recent migration or population admixture. We also discovered unexpectedly high between-year genetic differentiation (FST) for breeding sites, suggesting that breeding groups vary over localized space and time. While environmental factors associated with high-elevation montane habitats apparently play an important role in shaping population differentiation, additional, species-specific biological processes must also be operating to account for observed deviations from temporal, among-year panmixia. Our study emphasizes the population-level insights that can be gained from highdensity sampling in space and time, and the highly substructured population biology that may characterize amphibians in extreme montane habitats.

Large wood maintains in-channel and floodplain habitats by influencing the biophysical character of the river corridor. Large wood dynamics in a river corridor are a product of watershed wide processes and also of local recruitment, transport, and storage. This complexity of scales added to the logistical constraints in taking measurements limits our understanding of large wood dynamics through the watershed. To begin to unravel this issue, we compiled a data set of the volume of large wood deposited annually into 131 reservoirs across Japan and compared large wood export to flow discharge and watershed characteristics (watershed size, latitude, channel slope, percent forest, and forest type). We found that large wood was predominately transported during peak flow events. Large wood export increased logarithmically with watershed area. The decreasing export rate of large wood per watershed area is interpreted as a combination of annual export variability in upper watersheds, a non-significant increase in large wood recruitment along the longitudinal gradient (potentially human influenced), the increase in long-term storage on adjacent large floodplains, and significant decay/fragmentation downstream. Watersheds 2 had a highly variable large wood export pattern, conforming generally to previously published work that suggest transport limitation in smaller watersheds. The data suggest the existence of an export threshold (∼ 75 km 2 ) where large wood export is no longer related to watershed size. Export across all watershed sizes was controlled by watershed characteristics (slope, percent forested, etc.) and peak discharge events. The connection with upstream watersheds and laterally with the floodplain increases the net flux of large wood through downstream transport and retransport of buried logs. Identifying rates of large wood transport from watershed connectivity as a potential key input process will improve our basic understanding of geomorphic and ecological patterns within the watershed. These results highlight the importance of understanding the local- and watershed-scale dynamics of large wood in creating and maintaining more heterogeneous riparian and aquatic habitat along the river corridor.

Conservation frequently requires the preservation or restoration of ecosystems in human-altered landscapes. Understanding these ecosystems requires matching patterns with processes at appropriate scales. On floodplains this necessitates coupling plant distributions with fine- and broadscale hydrologic patterns. This is particularly important when target species are of conservation concern, such as the blue elderberry (Sambucus mexicana). Blue elderberry is the sole host plant for the federally threatened Valley elderberry longhorn beetle, yet controls on the shrub’s distribution have largely been untested. We used nested hierarchical analyses to test hypotheses about the role of broad- and fine-scale variables structuring the distribution of elderberry in one undammed and three dammed rivers in California’s Central Valley (USA). Elderberry presence across the floodplains was primarily driven by broad-scale hydrologic regime, as represented by the relative elevation, floodplain width, and lateral distance of shrubs from the stream, and secondarily by sediment texture and topography. The patchy spatial distributions of elderberry were similar among the rivers, but habitat quality characteristics (i.e., controls on abundance and size) were driven by divergent variables with high stochasticity. We can improve our understanding of species distributions and outcomes of recovery efforts by scaling floodplain conservation efforts to broad-scale hydrologic patterns and by detecting crucial variables using a multi-scale methodology. Within these relatively large, self-defined landscape units, certain precautions and the application of an adaptive management approach could be employed to address the local-scale uncertainty in large-scale conservation efforts.

Societal constraints often limit full process restoration in large river systems, making local rehabilitation activities valuable for regeneration of riparian vegetation. A target of much mitigation and restoration is the federally threatened Valley elderberry longhorn beetle and its sole host plant, blue elderberry, in upper riparian floodplain environments. However, blue elderberry ecology is not well understood and restoration attempts typically have low success rates. We determined broad-scale habitat characteristics of elderberry in altered systems and examined associated plant species composition in remnant habitat. We quantified vegetation community composition in 139 remnant riparian forest patches along the Sacramento River and elderberry stem diameters along this and four adjacent rivers. The greatest proportion of plots containing elderberry was located on higher and older floodplain surfaces and in riparian woodlands dominated by black walnut. Blue elderberry saplings and shrubs with stems

An alluvial river channel typically meanders by eroding its outer banks and depositing sediments on the inside of bends, producing new land surfaces. Over time the landscape pattern created by these processes is important to the understanding of riparian plant ecology and the spatial structure of riparian forest development for restoration planning and design as well as other purposes. The middle sector of the Sacramento River is an actively meandering channel that deposits sediments in discrete new areas from fluvial geomorphic events creating a land age gradient. Newly formed land undergoes a primary succession by woody species such as willow and cottonwood communities that provide habitat for important conservation target species in California. Conservation and restoration of primary and secondary successional processes is an important management goal on the Sacramento River. The objectives of this paper were: (1) to develop and codify new methods to track the surficial chronological patterns of floodplain land age in a meandering river system, and (2) to analyze land production and the spatial distributions of gravel bars, riparian vegetation communities, and forest structure in relation to the land age gradient. Results from the ecological analysis indicate 71% of extant riparian vegetation was located within the 101-year meander zone; willow (18%) and cottonwood (31–43%) had the highest proportional canopy cover on lands aged 1–9 and 10–44 years, respectively. Potential applications of this approach for conservation and restoration planning and design of alluvial river floodplains are discussed.

River channel movement processes necessary to maintain the natural heterogeneity in wildlife-dependent riparian ecosystems often conflict with the need to protect adjacent human infrastructure (e.g. towns, bridges, water pumps). This conflict can be avoided through long-term planning efforts which use process-based geomorphic simulation modeling to forecast potential long-term (>50 years) landscape-level effects of water management decisions on river meander migration. We describe two management conflicts from the Sacramento River, California, USA, and analyze alternative management scenarios using results from a meander migration and cutoff simulation model. The first example shows that the existing rock revetment upstream from Woodson Bridge State Recreation Area alters the river meandering and causes erosion problems. Removing the revetment would relocate the channel and create a natural meander-neck chute cutoff, reducing erosion at the park while providing ecosystem benefits. The second example suggests that although a bank revetment is needed to prevent the river from moving away from a major water pump, removing an upstream bank revetment would provide habitat benefits without causing pump facility problems. These examples demonstrate the benefits of taking a long-term, landscape-level view when implementing infrastructure projects in dynamic landscapes.

© 2015 Elsevier B.V.. A crucial gap exists between the static nature of the United States' existing protected areas and the dynamic impacts of 21st century stressors, such as habitat loss and fragmentation and climate change. Connectivity is a valuable element for bridging that gap and building the ecological resilience of existing protected areas. However, creating terrestrial connectivity by designing individual migration corridors across fragmented landscapes is arguably untenable at a national scale. We explore the potential for use of riverine corridors in a Riparian Connectivity Network (RCN) as a potential contributor to a more resilient network of protected areas. There is ample scientific support for the conservation value of riparian areas, including their habitat, their potential to connect environments, and their ecosystem services. Our spatial analysis suggests that they could connect protected areas and have a higher rate of conservation management than terrestrial lands. Our results illustrate that the spatial backbone for an RCN is already in place, and existing policies favor riparian area protection. Furthermore, existing legal and regulatory goals may be better served if governance requirements and incentives are aligned with conservation efforts focused on riparian connectivity, as part of a larger landscape connectivity strategy. While much research on the effectiveness of riparian corridors remains to be done, the RCN concept provides a way to improve connectivity among currently protected areas. With focused attention, increased institutional collaboration, and improved incentives, these pieces could coalesce into a network of areas for biological conservation.

Environmental DNA (eDNA) degradation is a primary mechanism limiting the detection of rare species using eDNA techniques. To better understand the environmental drivers of eDNA degradation, we conducted a laboratory experiment to quantify degradation rates. We held bullfrog (Lithobates catesbeianus) tadpoles in microcosms, then removed the tadpoles and assigned the microcosms to three levels each of temperature, ultraviolet B (UV-B) radiation, and pH in a full factorial design. We collected water samples from each microcosm at six time steps (0 to 58 days). In all microcosms, most degradation occurred in the first three to 10 days of the experiment, but eDNA remained detectable after 58 days in some treatments. Degradation rates were lowest under cold temperatures (5 °C), low UV-B levels, and alkaline conditions. Higher degradation rates were associated with factors that contribute to favorable environments for microbial growth (higher temperatures, neutral pH, moderately high UV-B), indicating that the effects of these factors may be biologically mediated. The results of this experiment indicate that aquatic habitats that are colder, more protected from solar radiation, and more alkaline are likely to hold detectable amounts of eDNA longer than those that are warmer, sunnier, and neutral or acidic. These results can be used to facilitate better characterization of environmental conditions that reduce eDNA persistence, improved design of temporal sampling intervals and inference, and more robust detection of aquatic species with eDNA methods.

Flow regulation impacts the ecology of major rivers in various ways, including altering river channel migration patterns. Many current meander migration models employ a constant annual flow or dominant discharge value. To assess how flow regulation alters river function, variable annual flows -based on an empirical relationship between bank erosion rates and cumulative effective stream power - were added into an existing migration model. This enhanced model was used to evaluate the potential geomorphic and ecological consequences of four regulated flow scenarios (i.e., different hydrographs) currently being proposed on the Sacramento River in California. The observed rate of land reworked correlated significantly with observed cumulative effective stream power during seven time increments from 1956 to 1975 (r 2 = 0.74, p = 0.02). The river was observed to rework 3.0 ha/yr of land (a mean channel migration rate of 7.7 m/yr) with rates ranging from 0.8 ha/yr to 5.1 ha/yr (2.0 to 13.3 m/yr), during the analyzed time periods. Modeled rates of land reworked correlated significantly with observed rates of land reworked for the variable flow model (r 2 = 0.78, p = 0.009). The meander migration scenario modeling predicted a difference of 1 to 8 percent between the four flow management scenarios and the base scenario.

Environmental legislation in the US (i.e. NEPA) requires defining baseline conditions on current rather than historical ecosystem conditions. For ecosystems with long histories of multiple environmental impacts, this baseline method can subsequently lead to a significantly altered environment; this has been termed a 'sliding baseline'. In river systems, cumulative effects caused by flow regulation, channel revetment and riparian vegetation removal significantly impact floodplain ecosystems by altering channel dynamics and precluding subsequent ecosystem processes, such as primary succession. To quantify these impacts on floodplain development processes, we used a model of river channel meander migration to illustrate the degree to which flow regulation and riprap impact migration rates, independently and synergistically, on the Sacramento River in California, USA. From pre-dam conditions, the cumulative effect of flow regulation alone on channel migration is a reduction by 38%, and 42-44% with four proposed water diversion project scenarios. In terms of depositional area, the proposed water project would reduce channel migration 51-71 ha in 130 years without current riprap in place, and 17-25 ha with riprap. Our results illustrate the utility of a modeling approach for quantifying cumulative impacts. Model-based quantification of environmental impacts allow scientists to separate cumulative and synergistic effects to analytically define mitigation measures. Additionally, by selecting an ecosystem process that is affected by multiple impacts, it is possible to consider process-based mitigation scenarios, such as the removal of riprap, to allow meander migration and create new floodplains and allow for riparian vegetation recruitment.

Mechanism-based ecological models are a valuable tool for understanding the drivers of complex ecological systems and for making informed resource-management decisions. However, inaccurate conclusions can be drawn from models with a large degree of uncertainty around multiple parameter estimates if uncertainty is ignored. This is especially true in nonlinear systems with multiple interacting variables. We addressed these issues for a mechanism-based, demographic model of Populus fremontii (Fremont cottonwood), the dominant riparian tree species along southwestern U.S. rivers. Many cottonwood populations have declined following widespread floodplain conversion and flow regulation. As a result, accurate predictive models are needed to analyze effects of future climate change and water management decisions. To quantify effects of parameter uncertainty, we developed an analytical approach that combines global sensitivity analysis (GSA) with classification and regression trees (CART) and Random Forest, a bootstrapping CART method. We used GSA to quantify the interacting effects of the full range of uncertainty around all parameter estimates, Random Forest to rank parameters according to their total effect on model predictions, and CART to identify higher-order interactions. GSA simulations yielded a wide range of predictions, including annual germination frequency of 10-100%, annual first-year survival frequency of 0-50%, and patch occupancy of 0-100%. This variance was explained primarily by complex interactions among abiotic parameters including capillary fringe height, stage-discharge relationship, and floodplain accretion rate, which interacted with biotic factors to affect survival. Model precision was primarily influenced by well-studied parameter estimates with minimal associated uncertainty and was virtually unaffected by parameter estimates for which there are no available empirical data and thus a large degree of uncertainty. Therefore, research to improve model predictions should not always focus on the least-studied parameters, but rather those to which model predictions are most sensitive. We advocate the combined use of global sensitivity analysis, CART, and Random Forest to: (1) prioritize research efforts by ranking variable importance; (2) efficiently improve models by focusing on the most important parameters; and (3) illuminate complex model properties including nonlinear interactions. We present an analytical framework that can be applied to any model with multiple uncertain parameter estimates.

Quantifying the influence of the landscape on the genetic structure of natural populations remains an important empirical challenge, particularly for poorly studied, ecologically cryptic species. We conducted an extensive microsatellite analysis to examine the population genetics of the southern long-toed salamander (Ambystoma macrodactylum sigillatum) in a naturally complex landscape. Using spatially explicit modelling, we investigated the influence of the Sierra Nevada topography on potential dispersal corridors between sampled populations. Our results indicate very high-genetic divergence among populations, high within-deme relatedness, and little evidence of recent migration or population admixture. We also discovered unexpectedly high between-year genetic differentiation (F(ST)) for breeding sites, suggesting that breeding groups vary over localized space and time. While environmental factors associated with high-elevation montane habitats apparently play an important role in shaping population differentiation, additional, species-specific biological processes must also be operating to account for observed deviations from temporal, among-year panmixia. Our study emphasizes the population-level insights that can be gained from high-density sampling in space and time, and the highly substructured population biology that may characterize amphibians in extreme montane habitats.

River channel migration and cutoff events within large river riparian corridors create heterogeneous and biologically diverse landscapes. However, channel stabilization (riprap and levees) impede the formation and maintenance of riparian areas. These impacts can be mitigated by setting channel constraints away from the channel. Using a meander migration model to measure land affected, we examined the relationship between setback distance and riparian and off-channel aquatic habitat formation on a 28-km reach of the Sacramento River, California, USA. We simulated 100 years of channel migration and cutoff events using 11 setback scenarios: 1 with existing riprap and 10 assuming setback constraints from about 0.5 to 4 bankfull channel widths (bankfull width: 235 m) from the channel. The percentage of land reworked by the river in 100 years relative to current (riprap) conditions ranged from 172% for the 100-m constraint setback scenario to 790% for the 800-m scenario. Three basic patterns occur as the setback distance increases due to different migration and cutoff dynamics: complete restriction of cutoffs, partial restriction of cutoffs, and no restriction of cutoffs. Complete cutoff restriction occurred at distances less than about one bankfull channel width (235 m), and no cutoff restriction occurred at distances greater than about three bankfull widths (approximately 700 m). Managing for point bars alone allows the setbacks to be narrower than managing for cutoffs and aquatic habitat. Results suggest that site-specific "restriction of cutoff" thresholds can be identified to optimize habitat benefits versus cost of acquired land along rivers affected by migration processes.