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At least 1,369 records · Page 76Linked to original sources
USGS2016

Community disruptions and business costs for distant tsunami evacuations using maximum versus scenario-based zones

Well-executed evacuations are key to minimizing loss of life from tsunamis, yet they also disrupt communities and business productivity in the process. Most coastal communities implement evacuations based on a previously delineated maximum-inundation zone that integrates zones from multiple tsunami sources. To support consistent evacuation planning that protects lives but attempts to minimize community disruptions, we explore the implications of scenario-based evacuation procedures and use the California (USA) coastline as our case study. We focus on the land in coastal communities that is in maximum-evacuation zones, but is not expected to be flooded by a tsunami generated by a Chilean earthquake scenario. Results suggest that a scenario-based evacuation could greatly reduce the number of residents and employees that would be advised to evacuate for 24–36 h (178,646 and 159,271 fewer individuals, respectively) and these reductions are concentrated primarily in three counties for this scenario. Private evacuation spending is estimated to be greater than public expenditures for operating shelters in the area of potential over-evacuations ($13 million compared to $1 million for a 1.5-day evacuation). Short-term disruption costs for businesses in the area of potential over-evacuation are approximately $122 million for a 1.5-day evacuation, with one-third of this cost associated with manufacturing, suggesting that some disruption costs may be recouped over time with increased short-term production. There are many businesses and organizations in this area that contain individuals with limited mobility or access and functional needs that may have substantial evacuation challenges. This study demonstrates and discusses the difficulties of tsunami-evacuation decision-making for relatively small to moderate events faced by emergency managers, not only in California but in coastal communities throughout the world.

Natural Hazards↗
USGS2018

Natural hazards in Goma and the surrounding villages, East African Rift System

The city of Goma and its surrounding villages (Democratic Republic of the Congo, DRC) are among the world’s most densely populated regions strongly affected by volcanic hazards. In 2002, Nyiragongo volcano erupted destroying 10–15% of Goma and forced a mass evacuation of the population. Hence, the ~ 1.5 million inhabitants of Goma and Gisenyi (Rwanda) continue to live with the threat of new lava flows and other eruptive hazards from this volcano. The current network of fractures extends from Nyiragongo summit to Goma and continues beneath Lake Kivu, which gives rise to the fear that an eruption could even produce an active vent within the center of Goma or within the lake. A sub-lacustrine volcanic eruption with vents in the floor of the main basin and/or Kabuno Bay of Lake Kivu could potentially release about 300 km 3 of carbon dioxide (CO 2 ) and 60 km 3 of methane (CH 4 ) dissolved in its deep waters that would be catastrophic to populations (~ 2.5 million people) along the lake shores. For the time being, ongoing hazards related to Nyiragongo and Nyamulagira volcanoes silently kill people and animals, slowly destroy the environment, and seriously harm the health of the population. They include mazuku (CO 2 -rich locations where people often die of asphyxiation), the highly fluoridated surface and ground waters, and other locally neglected hazards. The volcanic gas plume causes poor air quality and acid rain, which is commonly used for drinking water. Given the large number of people at risk and the continued movement of people to Goma and the surrounding villages, there is an urgent need for a thorough natural hazards assessment in the region. This paper presents a general view of natural hazards in the region around Goma based on field investigations, CO 2 measurements in mazuku, and chemistry data for Lake Kivu, rivers and rainwater. The field investigations and the datasets are used in conjunction with extremely rich-historical (1897–2000) and recently published information about Nyiragongo and Nyamulagira volcanoes and Lake Kivu. We also present maps of mazuku and fractures in Goma, describe the volcanic eruption history with hazard assessment and mitigation implications, and consider social realities useful for an integrated risk management strategy.

Goma↗
USGS2011

Human dignity in concept and practice

Dignity seems to be something that virtually all people want. It is a seminal expression of the human experience that gains authority through the convergent demands of people worldwide. Even so, the human dignity concept is in unhelpful disarray. Dignity is variously viewed as an antecedent, a consequence, a value, a principle, and an experience, from philosophical, legal, pragmatic, psychological, behavioral, and cultural perspectives. We ask which if any of these human dignity concepts will likely serve our global common interests best, as both common ground and policy diagnostic? We examine four broad themes: dignity as (1) a metaphysical justification for human rights and duties, (2) virtuous comportment or behavior, (3) a perspective of “other,” and (4) a subjective experience of the individual, contingent on a broad and equitable sharing of values. We recommend viewing dignity as a commonwealth of individually assessed well-being, shaped by relationships with others, affected by the physical world, and framed in terms of values. Viewed this way, the idea of dignity accommodates the priorities of both individualistic and communitarian cultures. Conceiving of human dignity as a commonwealth of subjectively experienced value production and enjoyment has many practical policy implications.

Policy Sciences↗
USGS2011

Evidence of shift in C 4 species range in central Argentina during the late Holocene

Aim Millennial-scale biogeographic changes are well understood in many parts of the world, but little is known about long-term vegetation dynamics in subtropical regions. Here we investigate shifts in C 3 /C 4 plant abundance occurred in central Argentina during the past few millennia Methods We determined present day soil organic matter δ 13 C signatures of grasslands, shrublands and woodlands, containing different mixtures of C 3 and C 4 plants. We measured past changes in the relative cover of C 3 /C 4 plants by comparing δ 13 C values in soil profiles with present day δ 13 C signatures. We analyzed 14 C activity in soil depths that showed major changes in vegetation. Results Present day relative cover of C 3 /C 4 plants determines whole ecosystem δ 13 C signatures integrated as litter and superficial soil organic matter (R 2 = 0.78; p < 0.01). Deeper soils show a consistent shift in δ 13 C, indicating a continuous replacement of C 4 by C 3 plants since 3,870 (±210) YBP. During this period, the relative abundance of C 3 plants increased 32% (average across sites) with significant changes being observed in all studied ecosystems. Conclusions Our results show that C 4 species were more abundant in the past, but C 3 species became dominant during the late Holocene. We identified increases in the relative C 3 /C 4 cover in grasslands, shrublands and woodlands, suggesting a physiological basis for changes in vegetation. The replacement of C 4 by C 3 plants coincided with changes in climate towards colder and wetter conditions and could represent a climatically driven shift in the C 4 species optimum range.

Plant and Soil↗
USGS2018

Biocrusts: The living skin of the Earth

Biological soil crusts (biocrusts) form a “living skin” at the soil surface in many low productivity ecosystems around the world including water- and cold-limited environments, and early successional seres (Belnap et al. 2003). They may be composed of any configuration of soil surface-dwelling cyanobacteria, eukaryotic algae, lichens, mosses or liverworts, and support assemblages of decomposers and a faunal food web (Belnap et al. 2003). These soil surface communities have global relevance, as it has been recently estimated that they cover about 12% of the terrestrial surface currently (Rodriguez-Caballero et al. 2018). Biocrust communities are perhaps an ideal subject for the journal Plant and Soil, because they are simultaneously plant-like, due to their dominance by autotrophs, yet biocrusts are also clearly a physical feature of the soil given that component organisms are enmeshed in, adherent to, or otherwise in direct contact with the soil surface. The activity of the organisms is what engineers the well-aggregated thin layer at the soil surface that we recognize as a biocrust (Belnap et al. 2003). The contributions of biocrusts to ecosystem function has fueled much research interest, initially in the observation of biocrusts’ soil aggregating and erosion-resisting nature, and later as a multifunctional, globally-relevant ecosystem element instrumental in: 1. building or otherwise altering soil nutrient stocks through N-fixation (Elbert et al. 2012), dust trapping (Reynolds et al. 2001) and nutrient cycling (Strauss et al. 2012), 2. influencing hydrological properties of soil such as the water balance (Chamizo et al. 2016), and 3. The thermal energy balance of the ecosystem (Coradeau et al. 2016, Rutherford et al. 2017).

Plant and Soil↗
USGS2026

Understanding the links between functional performance and environment in cold desert ecosystems through the flagship biocrust forming moss Syntrichia caninervis

Background and aims Biocrust communities shape the soil surface in drylands, regulating important ecosystem properties. Despite this, few works address key functional attributes in these poikilohydric photosynthetic communities, including the length of metabolic activity in the field and its relationship with microclimate. We aim to disentangle the links between functional performance of a keystone biocrust species and environment in drylands, in order to better understand ecosystem functioning and services provided to the soil by these organisms. Methods We developed a 23 months monitoring experiment using very high resolution measurements of chlorophyll a fluorescence and microclimate in the field, comparing habitats with soils of different particle size composition and microclimatic conditions for the flagship biocrust moss Syntrichia caninervis on the Colorado Plateau, Utah, USA. Results While growing in soils of different composition did not impair the functional performance of the species, the sun/shade plasticity did affect key physiological attributes. Our results quantified a strategy based on avoidance of the most extreme environmental conditions, where metabolic activity only occur during 19.9% of the total time monitored. Relative humidity was the best microclimatic predictor of metabolic activity, and the annual length of metabolically active periods showed strong convergences with other drylands of the world. Conclusions These results collectively suggest a strong control of the environment over the ecosystem services provided by biocrusts. Our results include evidence for an improved understanding of the plasticity of S. caninervis to its variety of habitats, and its response to potential threats under different climate change scenarios.

Utah↗
USGS2005

Evidence for competitive dominance of Pink salmon (Oncorhynchus gorbuscha) over other Salmonids in the North Pacific Ocean

Relatively little is known about fish species interactions in offshore areas of the world's oceans because adequate experimental controls are typically unavailable in such vast areas. However, pink salmon (Oncorhynchus gorbuscha) are numerous and have an alternating-year pattern of abundance that provides a natural experimental control to test for interspecific competition in the North Pacific Ocean and Bering Sea. Since a number of studies have recently examined pink salmon interactions with other salmon, we reviewed them in an effort to describe patterns of interaction over broad regions of the ocean. Research consistently indicated that pink salmon significantly altered prey abundance of other salmon species (e.g., zooplankton, squid), leading to altered diet, reduced total prey consumption and growth, delayed maturation, and reduced survival, depending on species and locale. Reduced survival was observed in chum salmon (O. keta) and Chinook salmon (O. tshawytscha) originating from Puget Sound and in Bristol Bay sockeye salmon (O. nerka). Growth of pink salmon was not measurably affected by other salmon species, but their growth was sometimes inversely related to their own abundance. In all marine studies, pink salmon affected other species through exploitation of prey resources rather than interference. Interspecific competition was observed in nearshore and offshore waters of the North Pacific Ocean and Bering Sea, and one study documented competition between species originating from different continents. Climate change had variable effects on competition. In the North Pacific Ocean, competition was observed before and after the ocean regime shift in 1977 that significantly altered abundances of many marine species, whereas a study in the Pacific Northwest reported a shift from predation- to competition-based mortality in response to the 1982/1983 El Nino. Key traits of pink salmon that influenced competition with other salmonids included great abundance, high consumption rates and rapid growth, degree of diet overlap or consumption of lower trophic level prey, and early migration timing into the ocean. The consistent pattern of findings from multiple regions of the ocean provides evidence that interspecific competition can significantly influence salmon population dynamics and that pink salmon may be the dominant competitor among salmon in marine waters. ?? Springer 2005.

Reviews in Fish Biology and Fisheries↗
USGS2005

Introduction [to Issue 3]

Artificial propagation of aquatic organisms is increasing globally and currently accounts for approximately 32% of total world fishery production (Vannuccini, 2004). Between 1970 and 2000, aquaculture production of salmonids has grown from less than 200,000 metric tons per year to over 1.5 million metric tons (Tacon, 2003). In 1995, the number of Atlantic salmon (Salmo salar) far exceeded the carrying capacity of salmon in the wild but over 94% of all adult Atlantic salmon were in aquaculture environments (Gross, 1998). Since the 1970’s, concerns have arisen about interactions of hatchery and wild produced salmonids in native habitats. In response, research has addressed concerns about domestication and genetic impacts (Reisenbichler and McIntyre, 1977; Hindar et al., 1991; Waples, 1991; Clifford et al., 1998a; Fleming et al., 2000, 2002; Hard et al., 2000), transfer of disease and parasites (Johnsen and Jensen, 1994; Bakke and Harris, 1998), behavior of spawning adults (Fleming and Gross, 1992; Fleming et al., 1994; Økland et al., 1995; Youngston et al., 1998), differences in fitness traits and life history (Jonsson et al., 1991; Thodesen et al., 1999; McGinnity et al., 2003), and behavioral interactions between hatchery and wild juvenile salmon (Swain and Riddell, 1990; Johnsson et al., 1996; Clifford et al., 1998b). Much of this research has been driven by concerns about the impacts of escaped farmed Atlantic salmon in the North Atlantic Ocean (Hansen et al., 1991). Studies of the interactions between hatchery and wild salmonids, with few exceptions (see Myers et al., 2000), have primarily focused on interactions in freshwater environments. Interactions between hatchery and wild fishes in estuarine and marine environments have not received the same attention, but may have signifi- cant impacts on wild populations. To address this issue, we organized a symposium held at the 2003 annual meeting of the Western Division of the American Fisheries Society in San Diego, California. The session was titled Interactions of Hatchery and Wild Fishes in Marine and Estuarine Environments and included nine presentations. All but one presentation focused on salmonids. This Special Issue of Reviews in Fish Biology and Fisheries includes five papers that were submitted to the symposium.

Reviews in Fish Biology and Fisheries↗
USGS2017

Comparing stream-specific to generalized temperature models to guide salmonid management in a changing climate

Global climate change is predicted to increase air and stream temperatures and alter thermal habitat suitability for growth and survival of coldwater fishes, including brook charr (Salvelinus fontinalis), brown trout (Salmo trutta), and rainbow trout (Oncorhynchus mykiss). In a changing climate, accurate stream temperature modeling is increasingly important for sustainable salmonid management throughout the world. However, finite resource availability (e.g. funding, personnel) drives a tradeoff between thermal model accuracy and efficiency (i.e. cost-effective applicability at management-relevant spatial extents). Using different projected climate change scenarios, we compared the accuracy and efficiency of stream-specific and generalized (i.e. region-specific) temperature models for coldwater salmonids within and outside the State of Michigan, USA, a region with long-term stream temperature data and productive coldwater fisheries. Projected stream temperature warming between 2016 and 2056 ranged from 0.1 to 3.8 °C in groundwater-dominated streams and 0.2–6.8 °C in surface-runoff dominated systems in the State of Michigan. Despite their generally lower accuracy in predicting exact stream temperatures, generalized models accurately projected salmonid thermal habitat suitability in 82% of groundwater-dominated streams, including those with brook charr (80% accuracy), brown trout (89% accuracy), and rainbow trout (75% accuracy). In contrast, generalized models predicted thermal habitat suitability in runoff-dominated streams with much lower accuracy (54%). These results suggest that, amidst climate change and constraints in resource availability, generalized models are appropriate to forecast thermal conditions in groundwater-dominated streams within and outside Michigan and inform regional-level salmonid management strategies that are practical for coldwater fisheries managers, policy makers, and the public. We recommend fisheries professionals reserve resource-intensive stream-specific models for runoff-dominated systems containing high-priority fisheries resources (e.g. trophy individuals, endangered species) that will be directly impacted by projected stream warming.

Michigan↗
USGS2021

A bright spot analysis of inland recreational fisheries in the face of climate change: Learning about adaptation from small successes

Inland recreational fisheries have social, economic, and ecological importance worldwide but these fisheries are increasingly challenged by the diverse effects of climate change. Coupled with other anthropogenic stressors, climate change has contributed to declines in freshwater biodiversity of greater severity than those observed across marine or terrestrial taxa. At a macro level, inland fisheries are experiencing declines. There are, however, a number of success stories, or ‘bright spots,’ in inland recreational fisheries management, where innovative approaches are leading to increases in social and ecological well-being in the face of climate change. Cases such as these are important sources of inspiration and learning about adaptation to climate and environmental change. In this article, we analyze 11 examples of such ‘bright spots’ drawn from multiple jurisdictions around the world from which we extracted lessons that might apply to fisheries management challenges beyond the region and context of each case. Collectively, these bright spots highlight adaptive initiatives that allow for recreational fisheries management to mitigate to stressors associated with current and future climate change. Examples identified include community-based restoration projects, collaborative and adaptive approaches to short-term fisheries closures, transdisciplinary large-scale conservation projects, and conservation-minded efforts by individuals and communities. By highlighting examples of ‘small wins’ within inland recreational fisheries management, this review contributes to the idea that a ‘positive future’ for inland recreational fisheries in the face of climate change is possible and highlights potential strategies to adapt to current and future climate scenarios.

Reviews in Fish Biology and Fisheries↗
USGS2023

Global responses to the COVID-19 pandemic by recreational anglers: Considerations for developing more resilient and sustainable fisheries

The global COVID-19 pandemic resulted in many jurisdictions implementing orders restricting the movements of people to inhibit virus transmission, with recreational angling often either not permitted or access to fisheries and/or related infrastructure being prevented. Following the lifting of restrictions, initial angler surveys and licence sales suggested increased participation and effort, and altered angler demographics, but with evidence remaining limited. Here, we overcome this evidence gap by identifying temporal changes in angling interest, licence sales, and angling effort in world regions by comparing data in the ‘pre-pandemic’ (up to and including 2019); ‘acute pandemic’ (2020) and ‘COVID-acclimated’ (2021) periods. We then identified how changes can inform the development of more resilient and sustainable recreational fisheries. Interest in angling (measured here as angling-related internet search term volumes) increased substantially in all regions during 2020. Patterns in licence sales revealed marked increases in some countries during 2020 but not in others. Where licence sales increased, this was rarely sustained in 2021; where there were declines, these related to fewer tourist anglers due to movement restrictions. Data from most countries indicated a younger demographic of people who participated in angling in 2020, including in urban areas, but this was not sustained in 2021. These short-lived changes in recreational angling indicate efforts to retain younger anglers could increase overall participation levels, where efforts can target education in appropriate angling practices and create more urban angling opportunities. These efforts would then provide recreational fisheries with greater resilience to cope with future global crises, including facilitating the ability of people to access angling opportunities during periods of high societal stress.

Reviews in Fish Biology and Fisheries↗
USGS2007

Multi-scale responses of vegetation to removal of horse grazing from Great Basin (USA) mountain ranges

Although free-roaming equids occur on all of the world's continents except Antarctica, very few studies (and none in the Great Basin, USA) have either investigated their grazing effects on vegetation at more than one spatial scale or compared characteristics of areas from which grazing has been removed to those of currently grazed areas. We compared characteristics of vegetation at 19 sites in nine mountain ranges of the western Great Basin; sites were either grazed by feral horses (Equus caballus) or had had horses removed for the last 10-14 years. We selected horse-occupied and horse-removed sites with similar aspect, slope, fire history, grazing pressure by cattle (minimal to none), and dominant vegetation (Artemisia tridentata). During 1997 and 1998, line-intercept transects randomly located within sites revealed that horse-removed sites exhibited 1.1-1.9 times greater shrub cover, 1.2-1.5 times greater total plant cover, 2-12 species greater plant species richness, and 1.9-2.9 times greater cover and 1.1-2.4 times greater frequency of native grasses than did horse-occupied sites. In contrast, sites with horses tended to have more grazing-resistant forbs and exotic plants. Direction and magnitude of landscape-scale results were corroborated by smaller-scale comparisons within horse-occupied sites of horse-trail transects and (randomly located) transects that characterized overall site conditions. Information-theoretic analyses that incorporated various subsets of abiotic variables suggested that presence of horses was generally a strong determinant of those vegetation-related variables that differed significantly between treatments, especially frequency and cover of grasses, but also species richness and shrub cover and frequency. In contrast, abiotic variables such as precipitation, site elevation, and soil erodibility best predicted characteristics such as forb cover, shrub frequency, and continuity of the shrub canopy. We found species richness of plants monotonically decreased across sites as grazing disturbance increased, suggesting that either the bell-shaped diversity-disturbance curve of the intermediate-disturbance hypothesis does not apply in this system or that most sites are already all on the greater-disturbance slope of the curve. In our study, numerous vegetation properties of less-grazed areas and sites differed notably from horse-grazed sites at local and landscape scales during a wetter and an average-precipitation year. ?? 2007 Springer Science+Business Media B.V.

Plant Ecology↗
USGS2015

Local climate and cultivation, but not ploidy, predict functional trait variation in Bouteloua gracilis (Poaceae)

Efforts to improve the diversity of seed 18 resources for important restoration species has become a high priority for land managers in many parts of the world. Relationships between functional trait values and the environment from which seed sources are collected can provide important insights into patterns of local adaptation and guidelines for seed transfer. However, little is known about which functional traits exhibit genetic differentiation across populations of restoration species and thus may contribute to local adaptation. Here, we report the results of a common garden experiment aimed at assessing genetic (including ploidy level) and environmental regulation of several functional traits among populations of Bouteloua gracilis, a dominant C4 grass and the most highly utilized restoration species across much of the Colorado Plateau. We found that leaf size and specific leaf area (SLA) varied significantly among populations, and were strongly correlated with the source population environment from which seeds were collected. However, variation in ploidy level had no significant effect on functional traits. Leaves of plants grown from commercial seed releases were significantly larger and had lower SLA than those from natural populations, a result that is concordant with the overall relation between climate and these two functional traits. We suggest that the patterns of functional trait variation shown here may extend to other grass species in the western USA, and may serve as useful proxies for more extensive genecology research. Furthermore, we argue that care should be taken to develop commercial seed lines with functional trait values that match those of natural populations occupying climates similar to target restoration sites.

Plant Ecology↗
USGS2017

Climate and soil texture influence patterns of forb species richness and composition in big sagebrush plant communities across their spatial extent in the western US

Article for outlet: Plant Ecology. Abstract: Big sagebrush (Artemisia tridentata Nutt.) plant communities are widespread non-forested drylands in western North American and similar to all shrub steppe ecosystems world-wide are composed of a shrub overstory layer and a forb and graminoid understory layer. Forbs account for the majority of plant species diversity in big sagebrush plant communities and are important for ecosystem function. Few studies have explored the geographic patterns of forb species richness and composition and their relationships with environmental variables in these communities. Our objectives were to examine the small and large-scale spatial patterns in forb species richness and composition and the influence of environmental variables. We sampled forb species richness and composition along transects at 15 field sites in Colorado, Idaho, Montana, Nevada, Oregon, Utah, and Wyoming, built species-area relationships to quantify differences in forb species richness at sites, and used Principal Components Analysis and nonmetric multidimensional scaling to identify relationships among environmental variables and forb species richness and composition. We found that species richness was most strongly correlated with soil texture, while species composition was most related to climate. The combination of climate and soil texture influences water availability, with important consequences for forb species richness and composition, which suggests climate-change induced modification of soil water availability may have important implications for plant species diversity in the future. Our paper is the first to our knowledge to examine forb biodiversity patterns in big sagebrush ecosystems in relation to environmental factors across the big sagebrush region.

Colorado, Idaho, Montana, Nevada, Oregon, Utah, Wy↗
USGS2007

Mercury sedimentation in lakes in western Whatcom County, Washington, USA and its relation to local industrial and municipal atmospheric sources

Concentrations of mercury (Hg) were measured in six dated cores from four lakes in western Whatcom County, Washington, USA, that were at various bearings from a chlor-alkali plant, two municipal waste incinerators and a municipal sewage sludge incinerator. The importance of atmospheric emissions of Hg from these local municipal and industrial sources was evaluating by comparing the temporal trends in sedimentation of the lake cores with the emission history of each Hg species and by examining the geographical distribution of Hg sedimentation in relation to the region's primary wind pattern. Local municipal and industrial sources of atmospheric Hg were not responsible for the majority of the Hg in the upper layer of sediments of Whatcom County lakes because of (1) the significant enrichment of Hg in lake sediments prior to emissions of local industrial and municipal sources in 1964, (2) smaller increases in Hg concentrations occurred after 1964, (3) the similarity of maximum enrichments found in Whatcom County lakes to those in rural lakes around the world, (4) the inconsistency of the temporal trends in Hg sedimentation with the local emission history, and (5) the inconsistency of the geographic trends in Hg sedimentation with estimated deposition. Maximum enrichment ratios of Hg in lake sediments between 2 and 3 that are similar to rural areas in Alaska, Minnesota, and New England suggest that global sources of Hg were primarily responsible for increases of Hg in Whatcom County lakes beginning about 1900. ?? 2007 GovernmentEmployee: U.S. Government, Department of Interior, U.S. Geological Survey.

Water, Air, & Soil Pollution↗
USGS2005

Primary production in an impounded baldcypress swamp (Taxodium distichum) at the northern limit of the range

The ability of baldcypress (Taxodium distichum)swamps to maintain themselves near the northern limit of their range depends on their levels of production, which is not only are response to climate but also to local environmental factors(e.g., impoundment). We asked if primary production was reduced under impounded conditions and if species' responses to impoundment were individualistic or more generalized. To examine long-term production trends in a permanently impounded baldcypress swamp, a 6-year study of leaf litterfall was conducted in Buttonland Swamp, Illinois, which had been impounded for 10 years before the beginning of the study. Buttonland Swamp is at the northern boundary of the baldcypress swamp region along the Cache River, Illinois, in the Mississippi River Alluvial Valley of the United States. When the litter production of impounded sites was compared to those with natural hydrology in the same region, impounded sites had about half of the total litterfall of natural sites. Overall, leaf litterfall rates declined during the study(201 vs. 113 gm-2 yr-1), but the pattern was negatively correlated with water depth, which explained 97% of the variation in the data. Along the transect with the lowest mean minimum water depth(<0.5 cm), leaf litterfall decreased linearly over 6 years from 377 to 154gm-2 yr-1. Total leaf litterfall rates were lower at the other three depths(5, 43, and 49 cm mean minimum water depths)and remained below 200 gm-2 yr -1 throughout the study. Acer saccharinum, Nyssa aquatica, and Salix nigra were most responsible for the decline in total leaf litterfall. Amounts of leaf litterfall of T. distichum and Liquidambar styraciflua also generally decreased, while that of Cephalanthus occidentalis increased overtime. Because species' responses to environmental factors such as impoundment are individualistic, models should be based on the responses of individual species, rather than on communities. Our study further suggests that the effects of climate change on impounded swamps may differ from those with natural hydrology, since impounded swamps already have reduced production levels. This finding is particularly relevant since the hydrology of the majority of the world's riverine ecosystems has been altered. ?? Springer 2005.

Conference Paper↗
USGS2024

Identifying conditions where reed canarygrass (Phalaris arundinacea) functions as a driver of forest loss in the Upper Mississippi River floodplain under different hydrological scenarios

Most of the world’s river-floodplain ecosystems are simultaneously undergoing modifications to their hydrological regimes and experiencing species invasions, making it unclear whether invasive species are the main drivers of ecosystem change or simply responding to changes in the hydrological regime. We simulated patterns of forest recruitment and succession in a 2500-ha portion of the Upper Mississippi River floodplain with and without removal of invasive Phalaris arundinacea and under two different future 100-year hydrological scenarios: a future maintaining the average flooding conditions of the past 40 years (random) and a future that projects an observed upward 40-year trend in flooding conditions forward (trending). By comparing scenarios that included Phalaris removal and ones that did not, we were able to identify the conditions where Phalaris was the main driver of forest loss vs. the conditions where hydrology was the main driver of forest loss. Areas where Phalaris was the main driver of forest loss had mean annual flood inundation durations that were similar to areas that did not lose forest cover (60–90 growing season days), while areas where flooding was the main driver of forest loss had longer mean inundation durations (102–124 growing season days). In comparison to the random hydrology scenario, the trending scenario produced a decrease in the area over which Phalaris was identified as the main driver of forest loss and an increase in the area over which flood inundation was identified as the main driver of forest loss. Thus, if the observed trends in flooding continue, our model projects an increase in the area over which eradicating Phalaris is unlikely to result in the maintenance of forest cover. We used the Resist-Accept-Direct (RAD) framework to discuss potential management options to resist changes and maintain forest cover where Phalaris is likely to be the main driver of forest loss and to accept or direct changes in areas where forest loss is likely driven by hydrological change.

Iowa, Minnesota, Wisconsin↗
USGS2019

Preface—Evaluating the response of critical zone processes to human impacts with sediment source fingerprinting

1) Background: Critical Zone Processes in the Anthropocene The Earth’s Critical Zone encompasses a suite of interconnected processes in the near-surface lithosphere, pedosphere, biosphere, atmosphere, and hydrosphere (Brantley et al., 2007; Lin, 2010) (Fig. 1). Processes and interactions both within and between these various Critical Zone components supports life-sustaining ecosystem services and resources that establish the foundation for humanity (NRC, 2001). This includes the formation production of fertile soils, flourishing vegetation, productive rivers, lakes and oceans, and our life-sustaining atmosphere (Gaillardet, 2014; Guo and Lin, 2016). Rapid population growth, land use intensification, and global environmental change are disturbing many of these fundamental Critical Zone processes. More than half of the Earth’s terrestrial surface is now impacted by anthropogenic activities (e.g., clearing, grazing, plowing, mining, and logging) (Hooke et al., 2012; Richter and Mobley, 2009). These changes are so widespread and pervasive that the great acceleration of socioeconomic development that occurred around 1950 (Fig. 2) has been recommended to delineate the dawn of the Anthropocene (Waters et al., 2016). Although the utility of adopting and delineating the Anthropocene as the current epoch is subject to debate (Crutzen, 2002; Ruddiman et al., 2015; Smith and Zeder, 2013), the concept effectively highlights both the nature and the extent of our global impact on Earth’s Critical Zone. Soil forming processes and ecosystem services provided by the pedosphere are central to the Critical Zone (Banwart et al., 2011; Lin, 2010). Many of these processes have been disturbed by the agricultural intensification that coincided with the great acceleration resulting in unsustainable land use practices now outpacing soil formation processes (Brantley et al., 2007). As agricultural landscapes now cover an area equivalent to what was scoured during the last glacial maximum (Amundson et al., 2007), the broad-scale intensification of anthropogenic activities has resulted in significant on- and off-site impacts. On-site, soil loss has resulted in decreases in soil fertility and agricultural yields (Ladha et al., 2009) threatening the ability to feed the world’s growing population (Brantley et al., 2007). Off-site, the excess delivery of particulate matter downstream is degrading riverine, lacustrine, and estuarine ecosystems (Bilotta and Brazier, 2008; Clark, 1985; Owens et al., 2005). The challenge, as noted by Brantley et al., (2007), is that despite our society having over 10,000 years of experience working with soils, our conceptual and quantitative models remain inadequate at predicting Critical Zone dynamics under current conditions. Notwithstanding growing pressure for improved environmental management, we still have a limited capacity to predict changes in the Critical Zone in response to anthropogenic activities owing to the multiple spatial and temporal scales at which these complex processes and feedbacks are manifest. As river basin systems are impacted by many of these processes, a deep understanding of soil-sediment continuum dynamics may provide a valuable framework for evaluating the disturbance response of Critical Zone processes. Understanding these processes may also provide land and resource managers with the information necessary to manage both the on-site and off-site effects of accelerated soil erosion.

Journal of Soils and Sediments↗