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Afforestation Effects on Soil Carbon Storage in the United States: A Synthesis
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Afforestation (tree establishment on nonforested land) is a management option for increasing terrestrial C sequestration and mitigating rising atmo- spheric carbon dioxide because, compared to nonforested land uses, afforestation increases C storage in aboveground pools. However, because terrestrial ecosystems typically store most of their C in soils, afforestation impacts on soil organic carbon (SOC) storage are critical components of eco- system C budgets. We applied synthesis methods to identify the magnitude and drivers of afforestation impacts on SOC, and the temporal and verti- cal distributions of SOC change during afforestation in the United States. Meta-analysis of 39 papers from 1957 to 2010 indicated that previous land use drives afforestation impacts on SOC in mineral soils (overall average = +21%), but mined and other industrial lands (+173%) and wildlands (+31%) were the only groups that specifically showed categorically significant increases. Temporal patterns of SOC increase were statistically significant on former industrial and agricultural lands (assessed by continuous meta- analysis), and suggested that meaningful SOC increases require ≥15 and 30 yr of afforestation, respectively. Meta-analysis of 13C data demonstrated the greatest SOC changes occur at the surface soil of the profile, although par- tial replacement of C stocks derived from previous land uses was frequently detectable below 1 m. A geospatial analysis of 409 profiles from the National Soil Carbon Network database supported 13C meta-analysis results, indicating that transition from cultivation to forest increased A horizon SOC by 32%. In sum, our findings demonstrate that afforestation has significant, positive effects on SOC sequestration in the United States, although these effects require decades to manifest and primarily occur in the uppermost (and per- haps most vulnerable) portion of the mineral soil profile.
Abbreviations: BD, bulk density; CI, confidence interval; MAP, mean annual precipitation; MAT, mean annual temperature; SOC, soil organic carbon.
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Faustian bargains? Restoration realities in the context of biodiversity offset policies
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The science and practice of ecological restoration are increasingly being called upon to compensate for the loss of biodiversity values caused by development projects. Biodiversity offsetting—compensating for losses of biodiversity at an impact site by generating ecologically equivalent gains elsewhere—therefore places substantial faith in the ability of restoration to recover lost biodiversity. Furthermore, the increase in offset-led restoration multiplies the consequences of failure to restore, since the promise of effective restoration may increase the chance that damage to biodiversity is permitted. But what evidence exists that restoration science and practice can reliably, or even feasibly, achieve the goal of ‘no net loss’ of biodiversity, and under what circumstances are successes and failures more likely? Using recent reviews of the restoration ecology literature, we examine the effectiveness of restoration as an approach for offsetting biodiversity loss, and conclude that many of the expectations set by current offset policy for ecological restoration remain unsupported by evidence. We introduce a conceptual model that illustrates three factors that limit the technical success of offsets: time lags, uncertainty and measurability of the value being offset. These factors can be managed to some extent through sound offset policy design that incorporates active adaptive management, time discounting, explicit accounting for uncertainty, and biodiversity banking. Nevertheless, the domain within which restoration can deliver ‘no net loss’ offsets remains small. A narrowing of the gap between the expectations set by offset policies and the practice of offsetting is urgently required and we urge the development of stronger links between restoration ecologists and those who make policies that are reliant upon restoration science. Keywords:Compensatory habitat - Conservation policy - Mitigation banking - Environmental risk - No net loss - Restoration success
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Biotic Drivers of Stream Planform: Implications for Understanding the Past and Restoring the Future
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Traditionally, stream channel planform has been viewed as a function of larger watershed and valley-scale physical variables, including valley slope, the amount of discharge, and sediment size and load. Biotic processes serve a crucial role in transforming channel planform among straight, braided, meandering, and anabranching styles by increasing stream-bank stability and the probability of avulsions, creating stable multithread (anabranching) channels, and affecting sedimentation dynamics. We review the role of riparian vegetation and channel-spanning obstructions—beaver dams and logjams—in altering channel–floodplain dynamics in the southern Rocky Mountains, and we present channel planform scenarios for combinations of vegetation and beaver populations or old-growth forest that control logjam formation. These conceptual models provide understanding of historical planform variability throughout the Holocene and outline the implications for stream restoration or management in broad, low-gradient headwater valleys, which are important for storing sediment, carbon, and nutrients and for supporting a diverse riparian community.
Keywords: stream planform, riparian vegetation, beaver, old-growth forest, restoration
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Ecological Restoration in the Light of Ecological History
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Ecological history plays many roles in ecological restoration, most notably as a tool to identify and
characterize appropriate targets for restoration efforts. However, ecological history also reveals deep human
imprints on many ecological systems and indicates that secular climate change has kept many targets
moving at centennial to millennial time scales. Past and ongoing environmental changes ensure that many
historical restoration targets will be unsustainable in the coming decades. Ecological restoration efforts
should aim to conserve and restore historical ecosystems where viable, while simultaneously preparing to
design or steer emerging novel ecosystems to ensure maintenance of ecological goods and services.
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Effects of Flow Regulation on Shallow-Water Habitat Dynamics and Floodplain Connectivity
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Our study examined the effects of flow regulation on the spatiotemporal availability of shallow habitat patches with slow current velocity (SSCV patches) and floodplain inundation in the unregulated Yellowstone River and the regulated Missouri River in Montana and North Dakota. We mapped representative sites and used hydraulic models and hydrograph data to describe the frequency and extent of floodplain inundation and the availability of SSCV habitat over time during different water years. In the Yellowstone River the distribution, location, and size of SSCV patches varied but followed an annual pattern that was tied to the snowmelt runoff hydrograph. There was less variation in patch distribution in the Missouri River, and the pattern of habitat availability was influenced by flow regulation. Regulated flows and their effects on channel mor- phology and patterns of vegetation establishment resulted in 3.0–3.5 times less area of inundated woody vegetation during normal and dry years in the Missouri River compared with the Yellow- stone River. The differences we observed in SSCV patch dynamics between rivers may have implications for fish populations and community structure through affecting the survival of early life stages. At a larger scale, the smaller area of vegetation inundated in the Missouri River suggests that nutrient cycling and the ecological benefits associated with a moving littoral zone are reduced by the altered flow and sediment regime in that river. Accurate assessments of the effects of flow alteration and successful efforts to restore riverine ecosystems will require consideration of physical and biotic processes that operate at multiple spatial and temporal scales.
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Experimental studies of dead-wood biodiversity — A review identifying global gaps in knowledge
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The importance of dead wood for biodiversity is widely recognized but strategies for conservation exist only in some regions worldwide. Most strategies combine knowledge from observational and experimental studies but remain preliminary as many facets of the complex relationships are unstudied. In this first global review of 79 experimental studies addressing biodiversity patterns in dead wood, we identify major knowledge gaps and aim to foster collaboration among researchers by providing a map of previous and ongoing experiments. We show that research has focused primarily on temperate and boreal forests, where results have helped in developing evidence-based conservation strategies, whereas comparatively few such efforts have been made in subtropical or tropical zones. Most studies have been limited to early stages of wood decomposition and many diverse and functionally important saproxylic taxa, e.g., fungi, flies and termites, remain under-represented. Our meta-analysis confirms the benefits of dead-wood addition for biodiversity, particularly for saproxylic taxa, but shows that responses of non-saproxylic taxa are heterogeneous. Our analysis indicates that global conservation of organisms associated with dead wood would benefit most by prioritizing research in the tropics and other neglected regions, focusing on advanced stages of wood decomposition and assessing a wider range of taxa. By using existing experimental set-ups to study advanced decay stages and additional taxa, results could be obtained more quickly and with less effort compared to initiating new experiments.
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Pedoecological Modeling to Guide Forest Restoration using Ecological Site Descriptions
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the u.s. department of agriculture (usda)-natural resources conservation service (nrcs) uses an ecological site description (esd) framework to help incorporate interactions between local soil, climate, flora, fauna, and humans into schema for land management decision-making. we demonstrate esd and digital soil mapping tools to (i) estimate potential o horizon carbon (c) stock accumulation from restoring alternative ecological states in high-elevation forests of the central appalachian Mountains in west Virginia (wV), usa, and (ii) map areas in alternative ecological states that can be targeted for restoration. this region was extensively disturbed by clear-cut harvests and related fires during the 1880s through 1930s. we combined spodic soil property maps, recently linked to historic red spruce–eastern hemlock (Picea rubens–Tsuga canadensis) forest communities, with current forest inventories to provide guidance for restoration to a historic reference state. this allowed mapping of alternative hardwood states within areas of the spodic shale uplands conifer forest (scF) ecological site, which is mapped along the regional conifer-hardwood transition of the central appalachian Mountains. Plots examined in these areas suggest that many of the spruce-hemlock dominated stands in wV converted to a hardwood state by historic disturbance have lost at least 10 cm of o horizon thickness, and possibly much more. Based on this 10 cm estimate, we calculate that at least 3.74 to 6.62 tg of c were lost from areas above 880 m elevation in wV due to historic disturbance of o horizons, and that much of these stocks and related ecosystem functions could potentially be restored within 100 yr under focused management, but more practical scenarios would likely require closer to 200 yr.
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Improving Wetland Restoration Success Webinar Series
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The Association of State Wetland Managers (ASWM) is pleased to invite you to attend the sixth presentation in our popular Improving Wetland Restoration Success webinar series.
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ASWM Webinar - Using Beaver as a Wetland Restoration Tool
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Restoration Lessons Learned and an Introduction to the Beaver Restoration Assessment Tool
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SARP Announces FY 2016 Aquatic Habitat Restoration Project Awards
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The U.S. Fish and Wildlife Service (USFWS) has approved National Fish Habitat Partnership (NFHP) projects to receive USFWS-NFHP FY 2016 funding.
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