Geology topics

Kurt P. Kowalski

Publications and source records attributed to Kurt P. Kowalski.

At least 55 records · Page 3Linked to original sources

USGS2018

Rhizophagy cycle: An oxidative process in plants for nutrient extraction from symbiotic microbes

In this paper, we describe a mechanism for the transfer of nutrients from symbiotic microbes (bacteria and fungi) to host plant roots that we term the ‘rhizophagy cycle.’ In the rhizophagy cycle, microbes alternate between a root intracellular endophytic phase and a free-living soil phase. Microbes acquire soil nutrients in the free-living soil phase; nutrients are extracted through exposure to host-produced reactive oxygen in the intracellular endophytic phase. We conducted experiments on several seed-vectored microbes in several host species. We found that initially the symbiotic microbes grow on the rhizoplane in the exudate zone adjacent the root meristem. Microbes enter root tip meristem cells—locating within the periplasmic spaces between cell wall and plasma membrane. In the periplasmic spaces of root cells, microbes convert to wall-less protoplast forms. As root cells mature, microbes continue to be subjected to reactive oxygen (superoxide) produced by NADPH oxidases (NOX) on the root cell plasma membranes. Reactive oxygen degrades some of the intracellular microbes, also likely inducing electrolyte leakage from microbes—effectively extracting nutrients from microbes. Surviving bacteria in root epidermal cells trigger root hair elongation and as hairs elongate bacteria exit at the hair tips, reforming cell walls and cell shapes as microbes emerge into the rhizosphere where they may obtain additional nutrients. Precisely what nutrients are transferred through rhizophagy or how important this process is for nutrient acquisition is still unknown.

Microorganisms↗

USGS2018

Using turbidity measurements to estimate total phosphorus and sediment flux in a Great Lakes coastal wetland

Coastal wetlands around the Laurentian Great Lakes in North America have the potential to intercept surface water coming off of the landscape and reduce the amount of nutrients and sediment entering the lakes. However, extensive coastal wetland areas have been isolated behind dikes and thus have limited interaction with nutrient-rich waters that contribute to harmful algal blooms and other water-quality issues. In this study, we developed a method to use high-frequency measurements of discharge and turbidity to estimate sediment and total phosphorus retention in a hydrologically reconnected coastal wetland. We found sediment and total phosphorus retention to be episodic and highly related to fluctuations in water level. Low water levels in Lake Erie in late 2012 resulted in low retention in the wetland, but sediment and total phosphorus retention increased as water levels rose in the first half of 2013. Overall, the reconnected wetland was a sink for both total phosphorus and suspended sediment and locally reduced phosphorus loading rates to Lake Erie. Additional wetland reconnection projects have the potential to further reduce phosphorus and sediment loading rates, which could improve local water quality and ecosystem health.

Ohio↗

USGS2018

Fungal disease prevention in seedlings of rice (Oryza sativa) and other grasses by growth-promoting seed-associated endophytic bacteria from invasive Phragmites australis

Non-cultivated plants carry microbial endophytes that may be used to enhance development and disease resistance of crop species where growth-promoting and protective microbes may have been lost. During seedling establishment, seedlings may be infected by several fungal pathogens that are seed or soil borne. Several species of Fusarium , Pythium and other water moulds cause seed rots during germination. Fusarium blights of seedlings are also very common and significantly affect seedling development. In the present study we screened nine endophytic bacteria isolated from the seeds of invasive Phragmites australis by inoculating onto rice, Bermuda grass ( Cynodon dactylon ), or annual bluegrass ( Poa annua ) seeds to evaluate plant growth promotion and protection from disease caused by Fusarium oxysporum . We found that three bacteria belonging to genus Pseudomonas spp. (SLB4- P. fluorescens , SLB6- Pseudomonas sp. and SY1- Pseudomonas sp.) promoted seedling development, including enhancement of root and shoot growth, and stimulation of root hair formation. These bacteria were also found to increase phosphate solubilization in in vitro experiments. Pseudomonas sp. (SY1) significantly protected grass seedlings from Fusarium infection. In co-culture experiments, strain SY1 strongly inhibited fungal pathogens with 85.71% growth inhibition of F. oxysporum , 86.33% growth inhibition of Curvularia sp. and 82.14% growth inhibition of Alternaria sp. Seedlings previously treated with bacteria were found much less infected by F. oxysporum in comparison to non-treated controls. On microscopic observation we found that bacteria appeared to degrade fungal mycelia actively. Metabolite products of strain SY1 in agar were also found to inhibit fungal growth on nutrient media. Pseudomonas sp. (SY1) was found to produce antifungal volatiles. Polymerase chain reaction (PCR) amplification using specific primers for pyrrolnitirin synthesis and HCN (hydrogen cyanide) production suggested presence of genes for both compounds in the genome of SY1. HCN was detected in cultures of SY1. We conclude that microbes from non-cultivated plants may provide disease protection and promote growth of crop plants.

Microorganisms↗

USGS2017

Fungal endophytes from seeds of invasive, non-native Phragmites australis and their potential role in germination and seedling growth

Background and aims We characterized fungal endophytes of seeds of invasive, non-native Phragmites from three sites in the Great Lakes region to determine if fungal symbiosis could contribute to invasiveness through their effects on seed germination and seedling growth. Methods Field-collected seeds were surface sterilized and plated on agar to culture endophytes for ITS sequencing. Prevalence of specific endophytes from germinated and non-germinated seeds, and from seedlings, was compared. Results One-third of 740 seeds yielded endophyte isolates. Fifteen taxa were identified with Alternaria sp. representing 54% of all isolates followed by Phoma sp. (21%) and Penicillium corylophilum (12%). Overall germination of seeds producing an isolate (36%) was significantly higher than seeds not producing an isolate (20%). Penicillium in particular was strongly associated with increased germination of seeds from one site. Sixty-three isolates and 11 taxa were also obtained from 30 seedlings where Phoma , Penicillium and Alternaria respectively were most prevalent. There was a significant effect of isolating an endophyte from the seed on seedling growth. Conclusions These results suggest that many endophyte taxa are transmitted in seeds and can increase seed germination and seedling growth of invasive Phragmites . The role of fungal endophytes in host establishment, growth and invasiveness in nature requires further research.

Michigan, Ohio↗

USGS2017

Disease protection and allelopathic interactions of seed-transmitted endophytic pseudomonads of invasive reed grass ( Phragmites australis )

Background and aims Non-native Phragmites australis (haplotype M) is an invasive grass that decreases biodiversity and produces dense stands. We hypothesized that seeds of Phragmites carry microbes that improve seedling growth, defend against pathogens and maximize capacity of seedlings to compete with other plants. Methods We isolated bacteria from seeds of Phragmites , then evaluated representatives for their capacities to become intracellular in root cells, and their effects on: 1.) germination rates and seedling growth, 2.) susceptibility to damping-off disease, and 3.) mortality and growth of competitor plant seedlings (dandelion ( Taraxacum officionale F. H. Wigg) and curly dock ( Rumex crispus L.)). Results Ten strains (of 23 total) were identified and characterized; seven were identified as Pseudomonas spp. Strains Sandy LB4 ( Pseudomonas fluorescens ) and West 9 ( Pseudomonas sp.) entered root meristems and became intracellular. These bacteria improved seed germination in Phragmites and increased seedling root branching in Poa annua . They increased plant growth and protected plants from damping off disease. Sandy LB4 increased mortality and reduced growth rates in seedlings of dandelion and curly dock. Conclusions Phragmites plants associate with endophytes to increase growth and disease resistance, and release bacteria into the soil to create an environment that is favorable to their seedlings and less favorable to competitor plants.

Plant and Soil↗

USGS2016

Collaborations, research, and adaptive management to address nonnative Phragmites australis in the Great Lakes Basin

Phragmites australis , also known as common reed, is a native North American wetland grass that has grown in North America for thousands of years. More recently, a nonnative, invasive variety of Phragmites from Eurasia is rapidly invading wetlands across the continental United States and other parts of North America, where it negatively impacts humans and the environment. U.S. Geological Survey scientists, funded by the Great Lakes Restoration Initiative, are leading innovative efforts to improve management of nonnative Phragmites in the Great Lakes Basin.

Great Lakes Basin↗

USGS2016

Functional role of bacteria from invasive Phragmites australis in promotion of host growth

We hypothesize that bacterial endophytes may enhance the competitiveness and invasiveness of Phragmites australis. To evaluate this hypothesis, endophytic bacteria were isolated from P. australis. The majority of the shoot meristem isolates represent species from phyla Firmicutes, Proteobacteria, and Actinobacteria. We chose one species from each phylum to characterize further and to conduct growth promotion experiments in Phragmites. Bacteria tested include Bacillus amyloliquefaciens A9a, Achromobacter spanius B1, and Microbacterium oxydans B2. Isolates were characterized for known growth promotional traits, including indole acetic acid (IAA) production, secretion of hydrolytic enzymes, phosphate solubilization, and antibiosis activity. Potentially defensive antimicrobial lipopeptides were assayed for through application of co-culturing experiments and mass spectrometer analysis. B. amyloliquefaciens A9a and M. oxydans B2 produced IAA. B. amyloliquefaciens A9a secreted antifungal lipopeptides. Capability to promote growth of P. australis under low nitrogen conditions was evaluated in greenhouse experiments. All three isolates were found to increase the growth of P. australis under low soil nitrogen conditions and showed increased absorption of isotopic nitrogen into plants. This suggests that the Phragmites microbes we evaluated most likely promote growth of Phragmites by enhanced scavenging of nitrogenous compounds from the rhizosphere and transfer to host roots. Collectively, our results support the hypothesis that endophytic bacteria play a role in enhancing growth of P. australis in natural populations. Gaining a better understanding of the precise contributions and mechanisms of endophytes in enabling P. australis to develop high densities rapidly could lead to new symbiosis-based strategies for management and control of the host.

New Jersey↗

USGS2016

Evaluation of the functional roles of fungal endophytes of Phragmites australis from high saline and low saline habitats

Non-native Phragmites australis decreases biodiversity and produces dense stands in North America. We surveyed the endophyte communities in the stems, leaves and roots of collections of P. australis obtained from two sites with a low and high salt concentration to determine differences in endophyte composition and assess differences in functional roles of microbes in plants from both sites. We found differences in the abundance, richness and diversity of endophytes between the low saline collections (18 species distributed in phyla Ascomycota, Basidiomycota and Stramenopiles (Oomycota); from orders Dothideales, Pleosporales, Hypocreales, Eurotiales, Cantharellales and Pythiales; Shannon H = 2.639; Fisher alpha = 7.335) and high saline collections (15 species from phylum Ascomycota; belonging to orders Pleosporales, Hypocreales, Diaporthales, Xylariales and Dothideales; Shannon H = 2.289; Fisher alpha = 4.181). Peyronellaea glomerata , Phoma macrostoma and Alternaria tenuissima were species obtained from both sites. The high salt endophyte community showed higher resistance to zinc, mercury and salt stress compared to fungal species from the low salt site. These endophytes also showed a greater propensity for growth promotion of rice seedlings (a model species) under salt stress. The results of this study are consistent with the ‘habitat-adapted symbiosis hypothesis’ that holds that endophytic microbes may help plants adapt to extreme habitats. The capacity of P. australis to establish symbiotic relationships with diverse endophytic microbes that enhance its tolerance to abiotic stresses could be a factor that contributes to its invasiveness in saline environments. Targeting the symbiotic associates of P. australis could lead to more sustainable control of non-native P. australis .

Biological Invasions↗

USGS2016

Applying the collective impact approach to address non-native species: A case study of the Great Lakes Phragmites Collaborative

To address the invasion of non-native Phragmites in the Great Lakes, researchers at the U.S. Geological Survey—Great Lakes Science Center partnered with the Great Lakes Commission in 2012 to establish the Great Lakes Phragmites Collaborative (GLPC). The GLPC is a regional-scale partnership established to improve collaboration among stakeholders and increase the effectiveness of non-native Phragmites management and research. Rather than forming a traditional partnership with a narrowly defined goal, the GLPC follows the principles of collective impact to engage stakeholders, guide progress, and align resources to address this complex, regional challenge. In this paper, the concept and tenets of collective impact are described, the GLPC is offered as a model for other natural resource-focused collective impact efforts, and steps for establishing collaboratives are presented. Capitalizing on the interactive collective impact approach, the GLPC is moving toward a broadly accepted common agenda around which agencies and individuals will be able to better align their actions and generate measureable progress in the regional campaign to protect healthy, diverse ecosystems from damage caused by non-native Phragmites .

Biological Invasions↗

USGS2016

Diversity of fungal endophytes in non-native Phragmites australis in the Great Lakes

Plant–microbial interactions may play a key role in plant invasions. One common microbial interaction takes place between plants and fungal endophytes when fungi asymptomatically colonize host plant tissues. The objectives of this study were to isolate and sequence fungal endophytes colonizing non-native Phragmites australis in the Great Lakes region to evaluate variation in endophyte community composition among three host tissue types and three geographical regions. We collected entire ramets from multiple clones and populations, surface sterilized plant tissues, and plated replicate tissue samples from leaves, stems, and rhizomes on corn meal agar plates to culture and isolate fungal endophytes. Isolates were then subjected to Sanger sequencing of the ITS region of the nuclear ribosomal DNA. Sequences were compared to fungal databases to define operational taxonomic units (OTUs) that were analyzed statistically for community composition. In total, we obtained 173 endophyte isolates corresponding to 55 OTUs, 39 of which were isolated only a single time. The most common OTU corresponded most closely to Sarocladium strictum and comprised 25 % of all fungal isolates. More OTUs were found in stem tissues, but endophyte diversity was greatest in rhizome tissues. PERMANOVA analyses indicated significant differences in endophyte communities among tissue types, geographical regions, and the interaction between those factors, but no differences among individual ramets were detected. The functional role of the isolated endophytes is not yet known, but one genus isolated here ( Stagonospora ) has been reported to enhance Phragmites growth. Understanding the diversity and functions of Phragmites endophytes may provide targets for control measures based on disrupting host plant/endophyte interactions.

Great Lakes region↗

USGS2015

Functional role of an endophytic Bacillus amyloliquefaciens in enhancing growth and disease protection of invasive English ivy ( Hedera helix L. )

Background We hypothesize that invasive English ivy ( Hedera helix ) harbors endophytic microbes that promote plant growth and survival. To evaluate this hypothesis, we examined endophytic bacteria in English ivy and evaluated effects on the host plant. Methods Endophytic bacteria were isolated from multiple populations of English ivy in New Brunswick, NJ. Bacteria were identified as a single species Bacillus amyloliquefaciens . One strain of B. amyloliquefaciens , strain C6c, was characterized for indoleacetic acid (IAA) production, secretion of hydrolytic enzymes, phosphate solubilization, and antibiosis against pathogens. PCR was used to amplify lipopeptide genes and their secretion into culture media was detected by MALDI-TOF mass spectrometry. Capability to promote growth of English ivy was evaluated in greenhouse experiments. The capacity of C6c to protect plants from disease was evaluated by exposing B+ (bacterium inoculated) and B− (non-inoculated) plants to the necrotrophic pathogen Alternaria tenuissima . Results B. amyloliquefaciens C6c systemically colonized leaves, petioles, and seeds of English ivy. C6c synthesized IAA and inhibited plant pathogens. MALDI-TOF mass spectrometry analysis revealed secretion of antifungal lipopeptides surfactin, iturin, bacillomycin, and fengycin. C6c promoted the growth of English ivy in low and high soil nitrogen conditions. This endophytic bacterium efficiently controlled disease caused by Alternaria tenuissima . Conclusions This study suggests that B. amyloliquefaciens plays an important role in enhancing growth and disease protection of English ivy.

Plant and Soil↗

USGS2015

Advancing the science of microbial symbiosis to support invasive species management: a case study on Phragmites in the Great Lakes

A growing body of literature supports microbial symbiosis as a foundational principle for the competitive success of invasive plant species. Further exploration of the relationships between invasive species and their associated microbiomes, as well as the interactions with the microbiomes of native species, can lead to key new insights into invasive success and potentially new and effective control approaches. In this manuscript, we review microbial relationships with plants, outline steps necessary to develop invasive species control strategies that are based on those relationships, and use the invasive plant species Phragmites australis (common reed) as an example of how development of microbial-based control strategies can be enhanced using a collective impact approach. The proposed science agenda, developed by the Collaborative for Microbial Symbiosis and Phragmites Management, contains a foundation of sequential steps and mutually-reinforcing tasks to guide the development of microbial-based control strategies for Phragmites and other invasive species. Just as the science of plant-microbial symbiosis can be transferred for use in other invasive species, so too can the model of collective impact be applied to other avenues of research and management.

Frontiers in Microbiology↗

USGS2014

Fish assemblages, connectivity, and habitat rehabilitation in a diked Great Lakes coastal wetland complex

Fish and plant assemblages in the highly modified Crane Creek coastal wetland complex of Lake Erie were sampled to characterize their spatial and seasonal patterns and to examine the implications of the hydrologic connection of diked wetland units to Lake Erie. Fyke netting captured 52 species and an abundance of fish in the Lake Erie–connected wetlands, but fewer than half of those species and much lower numbers and total masses of fish were captured in diked wetland units. Although all wetland units were immediately adjacent to Lake Erie, there were also pronounced differences in water quality and wetland vegetation between the hydrologically isolated and lake-connected wetlands. Large seasonal variations in fish assemblage composition and biomass were observed in connected wetland units but not in disconnected units. Reestablishment of hydrologic connectivity in diked wetland units would allow coastal Lake Erie fish to use these vegetated habitats seasonally, although connectivity does appear to pose some risks, such as the expansion of invasive plants and localized reductions in water quality. Periodic isolation and drawdown of the diked units could still be used to mimic intermediate levels of disturbance and manage invasive wetland vegetation.

Transactions of the American Fisheries Society↗

USGS2014

Assessment of suitable habitat for Phragmites australis (common reed) in the Great Lakes coastal zone

In the Laurentian Great Lakes, the invasive form of Phragmites australis (common reed) poses a threat to highly productive coastal wetlands and shorelines by forming impenetrable stands that outcompete native plants. Large, dominant stands can derail efforts to restore wetland ecosystems degraded by other stressors. To be proactive, landscape-level management of Phragmites requires information on the current spatial distribution of the species and a characterization of areas suitable for future colonization. Using a recent basin-scale map of this invasive plant’s distribution in the U.S. coastal zone of the Great Lakes, environmental data (e.g., soils, nutrients, disturbance, climate, topography), and climate predictions, we performed analyses of current and predicted suitable coastal habitat using boosted regression trees, a type of species distribution modeling. We also investigated differential influences of environmental variables in the upper lakes (Lakes Superior, Michigan, and Huron) and lower lakes (Lakes St. Clair, Erie, and Ontario). Basin-wide results showed that the coastal areas most vulnerable to Phragmites expansion were in close proximity to developed lands and had minimal topographic relief, poorly drained soils, and dense road networks. Elevated nutrients and proximity to agriculture also influenced the distribution of Phragmites . Climate predictions indicated an increase in suitable habitat in coastal Lakes Huron and Michigan in particular. The results of this study, combined with a publicly available online decision support tool, will enable resource managers and restoration practitioners to target and prioritize Phragmites control efforts in the Great Lakes coastal zone.

Great Lakes↗

USGS2014

2011 Summary: Coastal wetland restoration research

The Great Lakes Restoration Initiative (GLRI) projects currently taking place in Great Lakes coastal wetlands provide a unique opportunity to study ecosystem response to management actions as practitioners strive to improve wetland function and increase ecosystem services. Through a partnership between the U.S. Geological Survey – Great Lakes Science Center (GLSC), U.S. Fish and Wildlife Service (USFWS), and Ducks Unlimited, a GLRI-funded project has reestablished the hydrologic connection between an intensively managed impounded wetland (Pool 2B) and Crane Creek, a small Lake Erie tributary, by building a water-control structure that was opened in the spring of 2011. The study site is located within the USFWS Ottawa National Wildlife Refuge (ONWR) and lies within the boundaries of the U.S. Environmental Protection Agency (EPA)-designated Maumee River Area of Concern. The broad objective of the project is to evaluate how hydrologically reconnecting a previously diked wetland impacts fish, mollusks, and other biota and affects nutrient transport, nutrient cycling, water quality, flood storage, and many other abiotic conditions. The results from this project suggest large system-wide benefits from sustainable reestablishment of lake-driven hydrology in this and other similar systems. We comprehensively sampled water chemistry, fish, birds, plants, and invertebrates in Crane Creek coastal wetlands, Pool 2A (a reference diked wetland), and Pool 2B (the reconnected wetland) in 2010 and 2011 to: 1) Characterize spatial and seasonal patterns for these parameters. 2) Examine ecosystem response to the opening of a water-control structure that allows fish passage Our sampling efforts have yielded data that reveal striking changes in water quality, hydrology, and fish assemblages in our experimental unit (2B). Prior to the reconnection, the water chemistry in pools 2A and 2B were very similar. Afterwards, we found that the water chemistry in reconnected Pool 2B was more similar to Crane Creek (e.g., greater turbidity, higher concentration of nitrogen). Sites closest to the structure showed the most creek influence with that influence decreasing with distance from the structure, suggesting that input water from Crane Creek is not mixing fully with the pool water. We also found that water level fluctuations were much greater in the reconnected wetland due to the influence of seiches in Lake Erie. We measured the nutrient concentrations of water flowing into and out of Pool 2B during seiche events and found that the phosphorous and nitrogen concentrations generally were drastically reduced after pulsing through the reconnected wetland. Fish response to the reconnection was equally striking. High-resolution sonar revealed extensive bidirectional movement of fish through the structure on a daily and seasonal basis. There also were significant increases in both the catch per unit effort (CPUE) and the species richness of all sites in Pool 2B from 2010 to 2011. Reconnecting the diked pool to the larger Crane Creek wetland complex, and therefore Lake Erie, has opened up rich new habitat for many fish species. Thirteen species of fish not previously found in the pool entered through the structure and actively used the reconnected wetland. We also found that the wetland functions as a productive spawning ground and nursery area with notable shifts in the predominant age-class of several species of fish, especially northern pike. We observed no negative effects of reconnection on the avian or vegetative communities. All sites within the connected pool had increases in diversity and abundance in the avian community and decreases in the species richness and Floristic Quality Assessment Index values for vegetative communities. After one year of study, data suggest that maintaining a hydrologic connection between diked and coastal wetlands in Lake Erie allows fishes to use vegetated habitats regularly, reduces the concentration of nutrients in coastal waters, and maintains productive habitats for birds and other biota. It will be important to continue to monitor the status of the reconnected wetland to determine the effect of long-term connection to Crane Creek and Lake Erie. If conditions degrade, periodic management actions involving hydrologic isolation of the rehabilitated coastal wetland could be used to mimic intermediate levels of disturbance and maintain wetland vegetation.

Report↗

USGS2013

Mapping invasive Phragmites australis in the coastal Great Lakes with ALOS PALSAR satellite imagery for decision support

The invasive variety of Phragmites australis (common reed) forms dense stands that can cause negative impacts on coastal Great Lakes wetlands including habitat degradation and reduced biological diversity. Early treatment is key to controlling Phragmites, therefore a map of the current distribution is needed. ALOS PALSAR imagery was used to produce the ﬁrst basin-wide distribution map showing the extent of large, dense invasive Phragmites-dominated habitats in wetlands and other coastal ecosystems along the U.S. shore of the Great Lakes. PALSAR is a satellite imaging radar sensor that is sensitive to differences in plant biomass and inundation patterns, allowing for the detection and delineation of these tall (up to 5 m), high density, high biomass invasive Phragmites stands. Classiﬁcation was based on multi-season ALOS PALSAR L-band (23 cm wavelength) HH and HV polarization data. Seasonal (spring, summer, and fall) datasets were used to improve discrimination of Phragmites by taking advantage of phenological changes in vegetation and inundation patterns over the seasons. Extensive ﬁeld collections of training and randomly selected validation data were conducted in 2010–2011 to aid in mapping and for accuracy assessments. Overall basin-wide map accuracy was 87%, with 86% producer's accuracy and 43% user's accuracy for invasive Phragmites. The invasive Phragmites maps are being used to identify major environmental drivers of this invader's distribution, to assess areas vulnerable to new invasion, and to provide information to regional stakeholders through a decision support tool.

Lake Erie;Lake Huron;Lake Michigan;Lake Ontario;La↗

USGS2010

Georeferencing the Large-Scale Aerial Photographs of a Great Lakes Coastal Wetland: A Modified Photogrammetric Method

The geocontrol template method was developed to georeference multiple, overlapping analog aerial photographs without reliance upon conventionally obtained horizontal ground control. The method was tested as part of a long-term wetland habitat restoration project at a Lake Erie coastal wetland complex in the U.S. Fish and Wildlife Service Ottawa National Wildlife Refuge. As in most coastal wetlands, annually identifiable ground-control features required to georeference photo-interpreted data are difficult to find. The geocontrol template method relies on the following four components: (a) an uncontrolled aerial photo mosaic of the study area, (b) global positioning system (GPS) derived horizontal coordinates of each photo’s principal point, (c) a geocontrol template created by the transfer of fiducial markings and calculated principal points to clear acetate from individual photographs arranged in a mosaic, and (d) the root-mean-square-error testing of the system to ensure an acceptable level of planimetric accuracy. Once created for a study area, the geocontrol template can be registered in geographic information system (GIS) software to facilitate interpretation of multiple images without individual image registration. The geocontrol template enables precise georeferencing of single images within larger blocks of photographs using a repeatable and consistent method.

Ohio↗

USGS2006

A water-budget approach to restoring a sedge fen affected by diking and ditching

A vast, ground-water-supported sedge fen in the Upper Peninsula of Michigan, USA was ditched in the early 1900s in a failed attempt to promote agriculture. Dikes were later constructed to impound seasonal sheet surface flows for waterfowl management. The US Fish and Wildlife Service, which now manages the wetland as part of Seney National Wildlife Refuge, sought to redirect water flows from impounded C-3 Pool to reduce erosion in downstream Walsh Ditch, reduce ground-water losses into the ditch, and restore sheet flows of surface water to the peatland. A water budget was developed for C-3 Pool, which serves as the central receiving and distribution body for water in the affected wetland. Surface-water inflows and outflows were measured in associated ditches and natural creeks, ground-water flows were estimated using a network of wells and piezometers, and precipitation and evaporation/evapotranspiration components were estimated using local meteorological data. Water budgets for the 1999 springtime peak flow period and the 1999 water year were used to estimate required releases of water from C-3 Pool via outlets other than Walsh Ditch and to guide other restoration activities. Refuge managers subsequently used these results to guide restoration efforts, including construction of earthen dams in Walsh Ditch upslope from the pool to stop surface flow, installation of new water-control structures to redirect surface water to sheet flow and natural creek channels, planning seasonal releases from C-3 Pool to avoid erosion in natural channels, stopping flow in downslope Walsh Ditch to reduce erosion, and using constructed earthen dams and natural beaver dams to flood the ditch channel below C-3 Pool. Interactions between ground water and surface water are critical for maintaining ecosystem processes in many wetlands, and management actions directed at restoring either ground- or surface-water flow patterns often affect both of these components of the water budget. This approach could thus prove useful in guiding restoration efforts in many hydrologically altered and managed wetlands worldwide.

Journal of Hydrology↗