Papers in Natural Resources

Distribution and Prevalence of Echinococcus multilocularis in Wild Predators in Nebraska, Kansas, and Wyoming

S. T. Stroandt et al. — Tue, 02 Apr 2013 11:29:53 PDT

To further determine the distribution and prevalence of Echinococcus multilocularis in the central United States, 245 wild canids (125 red foxes, 120 coyotes) and 33 bobcats were collected from Nebraska, Kansas, and Wyoming and examined for this parasite. Animals examined included 11 red foxes from the western panhandle of Nebraska; 5 red foxes and 30 coyotes from southern Nebraska; 56 red foxes and 1 coyote from northeastern Nebraska; 20 red foxes, 63 coyotes, and 13 bobcats from northern Kansas; 2 red foxes, 26 coyotes, and 20 bobcats from southern Kansas; and 31 red foxes from eastcentral Wyoming. Of these, 27 of 72 (37.5%) red foxes from Nebraska were positive, including 2 of 11 (18.2%) from the western panhandle and 25 of 56 (44.6%) from the northeastern part of the state. Mean intensity of infection was 282 worms (range, 1–5,150). New distribution records were established for E. multilocularis in western Nebraska as well as for several northeastern counties. These findings support previous estimates that the southernmost front of the parasite’s range extends along the southern border of Wyoming, eastward through central Nebraska and central Illinois into Indiana and Ohio.

Modeling vulnerability of groundwater to pollution under future scenarios of climate change and biofuels-related land use change: A case study in North Dakota, USA

Ruopu Li et al. — Fri, 08 Feb 2013 13:14:00 PST

Modeling groundwater vulnerability to pollution is critical for implementing programs to protect groundwater quality.Most groundwater vulnerability modeling has been based on current hydrogeology and land use condi- tions. However, groundwater vulnerability is strongly dependent on factors such as depth-to-water, recharge and land use conditions thatmay change in response to future changes in climate and/or socio-economic condi- tions. In this research, a modeling framework, which employs three sets of models linked within a geographic information system (GIS) environment, was used to evaluate groundwater pollution risks under future climate and land use changes in North Dakota. The results showed that areas with high vulnerability will expand northward and/or northwestward in Eastern North Dakota under different scenarios. GIS-based models that account for future changes in climate and land use can help decision-makers identify potential future threats to groundwater quality and take early steps to protect this critical resource.

Use of Partially Fenced Fields to Reduce Deer Damage to Corn

Aaron M. Hildreth et al. — Mon, 04 Feb 2013 07:47:26 PST

White-tailed deer (Odocoileus virginianus) damage agricultural crops, often leading to significant economic losses for farmers. We used poly-mesh fence with wings to separate good deer cover from agricultural fields where crop damage by deer occurred primarily along this edge. In these cases, complete enclosure of the field with fencing may be unnecessary. The design used a 2.13-m-high polypropylene mesh fence erected along the wooded edge of a field with either 50-m or 150-m wings extending perpendicular from the fence line and wooded habitat. Fences reduced deer damage in cornfields 13.5% (F_1,6= _∞, P < 0.001). Average yield in fenced fields (10,211 kg/ha) was 1,708 kg/ha greater than in control fields, which, at US$0.155/kg, equals a net gain of US$265/ha. We found no difference in damage between fences with 50-m and 150-m wings (F_1,1 = 0.26, P = 0.695). Costs for materials and labor for erecting partial poly-mesh fences with wings were US$5.56/m and US$1.42/m, respectively. Mean total cost for partial poly-mesh fences with 50-m wings would be US$60.13/ha/year over a 10-year period, compared with US$82.30/ha/year for 150-m wings and US$184.16/ha/year for completely enclosing fields. Expected savings for partial poly-mesh fences with 50-m wings over a 10-year period were US$205/ha/year, as compared with damaged fields without fences. We concluded that poly-mesh fences with 50-m wings were cost-effective at reducing damage by deer to corn. Additional research should be conducted to determine efficacy of the more cost-effective high-tensile and poly-tape fences with wings.

A REVIEW OF INTERIOR LEAST TERN AND PIPING PLOVER MANAGEMENT, CONSERVATION, AND RECOVERY ON THE LOWER PLATTE RIVER, NEBRASKA

Mary Bomberger Brown et al. — Mon, 04 Feb 2013 07:27:56 PST

SUMMARY

The Lower Platte River in eastern Nebraska provides many resources for wildlife and a variety of stakeholders. This river and its major tributaries contain important nesting habitat for two state and federally-listed bird species, the Interior Least Tern (endangered; Sternula antillarum athalassos) and the Northern Great Plains Piping Plover (threatened; Charadrius melodus). Both species nest on bare or sparsely-vegetated expanses of sand in natural and human-created habitat, which occur in and along river channels; the Lower Platte River system is critical for the survival and recovery of both species.

The Lower Platte River in eastern Nebraska provides many resources for wildlife and a variety of stakeholders. This river and its major tributaries contain important nesting habitat for two state and federally-listed bird species, the Interior Least Tern (endangered; Sternula antillarum athalassos) and the Northern Great Plains Piping Plover (threatened; Charadrius melodus). Both species nest on bare or sparsely-vegetated expanses of sand in natural and human-created habitat, which occur in and along river channels; the Lower Platte River system is critical for the survival and recovery of both species.

In contrast to other river systems in Nebraska, there is no programmatic agreement or framework that generates a comprehensive Interior Least Tern and Piping Plover policy on the Lower Platte River. The Nebraska Game and Parks Commission (NGPC) and the Tern and Plover Conservation Partnership (TPCP), in cooperation with the U.S. Fish and Wildlife Service (USFWS), are responsible for making and implementing management decisions in this region. Collectively, these decisions constitute a de facto tern and plover policy for the Lower Platte River. The fundamental challenge with regard to policy-making on the Lower Platte River is how to conserve terns and plovers while balancing the needs and concerns of stakeholders.

This document serves as a foundation for developing management strategies for Interior Least Terns and Piping Plovers on the Lower Platte River. To meet this end, we provide a summary of the area’s geographic and political setting. Next, we provide detailed species descriptions for Interior Least Tern and Piping Plovers, including their ecology, population trends, and reasons for both species’ declines. Finally, we describe current management activities by the Nebraska Game and Parks Commission and the Tern and Plover Conservation Partnership.

We hope that this document will facilitate meaningful discussion about the future of the Lower Platte River and the people and wildlife that depend on it.

INTRODUCTION

The Lower Platte River in Nebraska is an important resource for a variety of stakeholders. The river has been, and will continue to be, modified to meet the needs of these stakeholders. The modifications take two general forms, 1) use of the river’s water and 2) control of the annual hydrological variation in the river system. Examples of the first include water diversion for agricultural or industrial purposes and of the second include levee construction for flood control. Balancing the needs for natural resource use by people and conservation of imperiled species in the ecosystem presents a challenge for decision-makers, resource agencies, and stakeholders. Currently, the river retains the capacity to create and maintain habitat for wildlife that depend on the river. However, as demands on the river’s resources accumulate, the river system may reach a threshold beyond which the river will lose much of its natural function and become unable to create and maintain habitat for wildlife. This has occurred on the nearby Central Platte and Missouri rivers, and massive efforts are underway to restore the components of the former ecosystem so the wildlife and economies that rely on these rivers are able to survive.

The Lower Platte River differs from the Central Platte and Missouri Rivers in that there is no omnibus agreement in place that controls the management of the river. Management of the Missouri River is dictated by congressional mandate (e.g., Flood Control Act of 1944 and USFWS Biological Opinion of 2003) and is carried out by the U.S. Army Corps of Engineers. Management of the Central Platte River is influenced by local water use policy and by a three-state cooperative agreement (Platte River Recovery Implementation Program, http://www.platteriverprogram.org) that implements actions to provide habitat for imperiled wildlife.

The Lower Platte River system provides habitat for two state and federally-listed bird species, the Interior Least Tern (Sternula antillarum athalassos) and the Northern Great Plains Piping Plover (Charadrius melodus). Terns and plovers breed along the river during late spring and summer and spend the remainder of year in migration or on their wintering areas. Both species nest in aggregations on bare or sparsely-vegetated expanses of sand in natural and human-created habitat. Natural habitat consists of sandbars within the river channel, which are created and maintained by geomorphological processes. Human-created habitat occurs outside the river channel and is created by industrial or commercial activities (i.e., sand and gravel mining, dredging and construction). The Interior Least Tern is state and federally listed as endangered (50 Federal Register 21784–21792), and the Great Plains Piping Plover is state and federally listed as threatened (50 Federal Register 50726–50734). Federal listing is under authority of the Endangered Species Act (1973), and state listing is under authority of the Nebraska Nongame and Endangered Species Conservation Act (Revised Statutes of Nebraska 1943; Neb. Stat 37–903; Neb. Stat 37–804). Federal and state listing provides protections for the birds, chicks, eggs, and their habitat.

2012 Interior Least Tern and Piping Plover Monitoring, Research, Management, and Outreach Report for the Lower Platte River, Nebraska

Mary B. Brown et al. — Mon, 04 Feb 2013 07:19:02 PST

Preface

This document reports on our monitoring, research, management, and outreach activities during the past 12 months (2012). We prepared it to inform our partners, cooperating agencies, funding sources, and other interested parties of our activities and to provide a preliminary summary of our results.

The data, data analyses, results, summaries, and interpretations found in this document are not final and should be considered as such when being cited or referred to in documents, reports, proposals, or presentations. Please contact us before using any of this material and for additional information that may have become available.

In an effort to make the information in this document more accessible, it is divided into five (5) sections: Introduction, Monitoring, Research, Management, and Outreach.

Introduction:

This section describes the project area and summarizes conditions encountered during the 2012 field season.

Monitoring: This section describes the data we collect every year for basic demographic analysis and includes the number of nests, adults, eggs, chicks, and fledglings found in the focus area. These data are collected and summarized in a form that allows comparison across the range of each species.

Research: This section describes our research objectives, data collection, and data analyses. Management: This section describes our actions to protect Interior Least Terns and Piping Plovers and their nests from interference.

Outreach: This section describes our efforts to increase public awareness and understanding of Interior Least Terns and Piping Plovers and to promote environmental literacy.

Introduction

The Lower Platte River and its major tributaries provide important nesting habitat for two state and federally protected bird species, the Interior Least Tern (Sternula antillarum athalassos) and Piping Plover (Charadrius melodus). The Tern and Plover Conservation Partnership (TPCP), based at the University of Nebraska-School of Natural Resources, and the Nongame Bird Program (NBP), based at the Nebraska Game and Parks Commission (NGPC), work cooperatively on Interior Least Tern and Piping Plover monitoring, research, management, and outreach activities in Nebraska. The TPCP and NBP focus on nesting areas along the Lower Platte, Loup, and Elkhorn rivers in the eastern part of the state; however, we also address tern and plover issues across the state and region. Our joint program includes terns and plovers nesting in natural, on-river habitats (midstream river sandbars) and human-created, off-river habitats (sand and gravel mines, dredging operations and lakeshore housing developments). The TPCP leads efforts on the off-river habitats, while the NBP leads efforts on the river habitats.

Focus Animals

The Interior Least Tern (Sternula antillarum athalassos) is the smallest tern found in North America. The species was first described in 1847 from a type specimen collected in Guadeloupe, West Indies (Checklist of the Birds of North America 1998. American Ornithologists’ Union). Meriwether Lewis and William Clark recorded their historical first observation of the Interior Least Tern on 5 August 1804 along the Missouri River in Nebraska, near present day Omaha. Today, the Interior Least Tern is a state and federally listed endangered species (50 Federal Register 21784–21792). It was placed on the Endangered Species List on 27 June 1985, and a Recovery Plan was issued in September 1990. As a result of its listing status the Interior Least Tern is protected by the Federal Endangered Species Act (1973) and the Nebraska Nongame and Endangered Species Conservation Act (Neb. Rev. Stat. § 37-801-11). A review of the species’ population status is currently being conducted by the USFWS (P. Hartfield, pers. comm.).

The Piping Plover (Charadrius melodus) is a small, migratory shorebird. The species was first described in 1824 from a type specimen collected in New Jersey (Checklist of the Birds of North America. 1998.American Ornithologists’ Union). Meriwether Lewis and William Clark observed Piping Plovers, and recorded their observations in what became the state of Nebraska, during their 1803–1805 “Voyage of Discovery” across North America. The Piping Plover is a state and federally listed threatened species (50 Federal Register 50726–50734). It was placed on the Endangered Species List on 10 January 1986, and the Northern Great Plains Recovery Plan (which covers plovers in Nebraska) was issued in May 1988. The listing status of this species is managed under the auspices of the Federal Endangered Species Act (1973) and the Nebraska Nongame and Endangered Species Conservation Act (Neb. Rev. Stat. § 37-801-11). Critical habitat for the Northern Great Plains breeding population was designated in Montana, Nebraska, South Dakota, and Minnesota on 11 September 2002 (67 Federal Register 57637). The United States District Court vacated the portion of critical habitat located in Nebraska on 13 October 2005; to date, it has not been reinstated. A review of the species’ population status was completed in 2009 and the recovery plan is currently being re-evaluated (C. Aron, pers. comm.).

Interior Least Terns and Piping Plovers are an integral part of the fauna of Nebraska. Interior Least Terns and Piping Plovers were among the first birds to be described in Nebraska by western explorers, and were known by Native Americans well before that. Historically, terns and plovers flourished on the sparsely-vegetated midstream sandbars of the Platte, Missouri, Loup, Elkhorn, and Niobrara rivers. However, much of this natural habitat has been lost due to anthropogenic changes in these river systems. The amount of suitable sandbar habitat has been reduced by the presence of invasive plant species, construction of dams and reservoirs, river channelization, bank stabilization, hydropower generation, and water diversion. Terns and plovers frequently nest on human-created habitats that occur outside of the river channel and are created by industrial and commercial activities such as sand and gravel mining, dredging, and construction. This change in nesting habitat from exclusively on-river sandbars to a combination of on- and off-river habitats is the result of the decrease in availability of river habitat and the increase in availability of human-created off-river habitats. Although human-created habitats offer alternative nesting sites during years where river sandbars are limited in availability, they are not likely to provide a suitable long-term substitute for riverine nesting habitat. Broad-scale alterations of the natural river systems that traditionally provided breeding habitat for Interior Least Terns and Piping Plovers have been a major contributor to population declines.

Loss of overwintering habitat also contributed to the decline of both species. Piping Plovers and Interior Least Terns spend about eight months of the year in their overwintering areas. Overwintering habitat for Northern Great Plains Piping Plovers occurs along the southern Atlantic coast from Florida to South Carolina, the Gulf of Mexico from northeastern Mexico to southwestern Florida, and the Bahamas. These overwintering habitats are characterized by wide beaches and a combination of sand flats, mudflats, tide pools, marshes, lagoons, and large inlets. Interior Least Terns spend the winter off-shore and along coasts, bays, estuaries, and river mouths near Central and South America. The principal threats to tern and plover overwintering habitat include habitat loss and degradation, increased residential and industrial development, and natural disasters (i.e., global sea level rise and hurricanes).

Modeling parasitism rate and parasitism risk: An illustration using a colonially nesting songbird, the red-winged blackbird Agelaius phoeniceus

Max Post van der Burg et al. — Wed, 30 Jan 2013 11:53:46 PST

Ornithologists interested in the drivers of nest success and brood parasitism benefit from the development of new analytical approaches. One example is the development of so-called “log exposure” models for analyzing nest success. However, analyses of brood parasitism data have not kept pace with developments in nest success analyses. The standard approach uses logistic regression which does not account for multiple parasitism events, nor does it prevent bias from using observed proportions of parasitized nests. Likewise, logistic regression analyses do not capture fine scale temporal variation in parasitism. At first glance, it might be tempting to apply log exposure models to parasitism data, but the process of parasitism is inherently different from the process of nest predation. We modeled daily parasitism rate as a Poisson process, which allowed us to correct potential biases in parasitism rate. We were also able to use our estimated parasitism rate to model parasitism risk as the probability of one or more parasitism events. We applied this model to red-winged blackbird Agelaius phoeniceus nesting colonies subject to parasitism by brown-headed cowbirds Molothrus ater. Our approach allowed us to model parasitism using a wider rage of covariates, especially functions of time. We found strong support for models combining temporal fluctuations in parasitism rate and nest-site characteristics. Similarly, we found that our annual predicted parasitism risk was lower on average than the risk estimated from observed parasitism levels. Our approach improves upon traditional logistic regression analyses and opens the door for more mechanistic modeling of the process of parasitism.

Estimating the Abundance of Long-billed Curlews in Nebraska

Cory J. Gregory et al. — Wed, 23 Jan 2013 10:14:43 PST

Long-billed Curlews (Numenius americanus) are shorebirds of high conservation concern in North America. Populations have declined in the last 150 yr primarily due to habitat loss and conversion. We conducted a 2-yr study to estimate the density and statewide abundance of breeding Long-billed Curlews in Nebraska during 2008 and 2009. Surveys were conducted during the prenesting period in April when Long-billed Curlews were likely to be detected. We used a simple random sample of roadside survey routes (N = 39), each consisting of 40 5-min point-counts at 800-m intervals. We modeled detection probability and found that wind speed negatively affected detectability, but found no evidence of either year effects or observer bias. We estimated there were 0.0038 Long-billed Curlews per hectare (0.38 Long-billed Curlews per km2) along survey routes and, by extrapolation, estimated there were 23,909 (SE = 1685; 95% CI: 20,810—27,471) Long-billed Curlews in Nebraska. Our population estimate suggests that ~15 to 22% of the United States population of Long-billed Curlews is found in Nebraska. Curlews were not evenly distributed within our survey area, with the highest densities in the central Sandhills, an area dominated by grass-stabilized sand dunes and shallow wetlands, and the lowest densities in predominantly agricultural areas. Because Long-billed Curlews in Nebraska face many potential threats resulting from land-use changes, monitoring of the breeding population should be continued. Our survey method was efficient and yielded interpretable results; other states or regions should consider adopting this approach for estimating curlew abundance.

Resumen. Estimando la abundancia de Numenius americanus en Nebraska Numenius americanus son aves playeras de alto interés de conservación en América del Norte. Sus poblaciones han disminuido en los últimos 150 años, debido principalmente a la pérdida y conversión de hábitat. Realizamos un estudio de 2 años para estimar la densidad y abundancia de individuos de N. americanus en estado reproductivo en toda Nebraska durante el 2008 y 2009. Los muestreos se realizaron durante el período previa a la anidación en abril, cuando los N. americanus son propensos a ser detectados. Utilizamos una muestra aleatoria simple de las transectas de muestreo a lo largo de las carreteras (N = 39), cada uno compuesto por 40 muestreos de 5-min, ubicados en intervalos de 800-m. Modelamos la probabilidad de detección y encontramos que la velocidad del viento afectó negativamente a la detectabilidad, pero no encontramos ninguna evidencia de efectos de año o de sesgo entre observadores. Estimamos que habían 0,0038 N. americanus por hectárea (0,38 N. americanus por km2) a lo largo de las transectas de muestreo y, por extrapolación, estimamos que habían 23 909 (EE = 1.685, IC 95%: 20 810–27 471) N. americanus en Nebraska. Nuestra estimación de la población sugiere que ~15 a 22% de la población de N. americanus en los Estados Unidos está en Nebraska. Los N. americanus no estaban distribuidos uniformemente dentro de nuestro área de estudio, con las densidades más altas en la región de los Sandhills centrales, una zona dominada por dunas de arena estabilizadas por pastos, y humedales poco profundos. Las densidades más bajas estaban en áreas predominantemente agrícolas. Debido a que los N. americanus en Nebraska enfrentan muchas amenazas potenciales, producto de cambios en el uso del suelo, el monitoreo de la población reproductora debe continuar. Nuestro método de muestreo fue eficiente y produjo resultados interpretables; otros estados o regiones deberían considerar adoptar este tipo de metodología para estimar la abundancia de Numenius.

Statistical Distribution of Streambed Vertical Hydraulic Conductivity along the Platte River, Nebraska

Cheng Cheng et al. — Fri, 21 Dec 2012 10:48:57 PST

Streambed vertical hydraulic conductivity (K_v) plays an important role in understanding and quantifying the stream–aquifer interactions. While several researchers have discussed the spatial variability of streambed horizontal hydraulic conductivity or K_vat one or several close-located sites in a river, they did not develop any statistical distribution analysis of streambed K_vat distant sites along a large river. In this paper, the statistical distribution and spatial variation of streambed K_vat 18 test sites in a 300-km reach of the Platte River in Nebraska are presented. Insitu permeameter tests using the falling-head method were carried out to calculate the streambed K_vvalues. Fine-grained sediments transported by two tributaries, the Loup River and the Elkhorn River, to the Platte River appear to result in lower streambed K_vvalues downstream of the confluences between the Platte River and the tributaries. The streambed K_vvalues were found to be normally distributed at nearly each test site. When the correlated K_vvalues were eliminated from the grid sampling plots, the remaining independent sub-datasets of streambed K_vvalues were still in normal distribution at each test site. Furthermore, the combined streambed K_vvalues upstream of the first confluence between the Platte River and the Loup River was normally distributed, which may be due to the lack of tributaries in-between and thus streambed sediments were well distributed in this reach and belonged to a single population of hydraulic conductivity values. In contrast, the combined dataset of all measurements conducted downstream of this confluence was no longer in normal distribution, presumably as a result of the mixing of different sediment sources.

Using slow-release permanganate candles to remediate PAH-contaminated water

Lindy Rauscher et al. — Fri, 16 Nov 2012 10:37:32 PST

Surface waters impacted by urban runoff in metropolitan areas are becoming increasingly contaminated with polycyclic aromatic hydrocarbons (PAHs). Slow-release oxidant candles (paraffin–KMnO₄) are a relatively new technology being used to treat contaminated groundwater and could potentially be used to treat urban runoff. Given that these candles only release permanganate when submerged, the ephemeral nature of runoff events would influence when the permanganate is released for treating PAHs. Our objective was to determine if slow-release permanganate candles could be used to degrade and mineralize PAHs. Batch experiments quantified PAH degradation rates in the presence of the oxidant candles. Results showed most of the 16 PAHs tested were degraded within 2–4 h. Using ¹⁴C-labled phenanthrene and benzo(a)pyrene, we demonstrated that the wax matrix of the candle initially adsorbs the PAH, but then releases the PAH back into solution as transformed, more water soluble products. While permanganate was unable to mineralize the PAHs (i.e., convert to CO₂), we found that the permanganate-treated PAHs were much more biodegradable in soil microcosms. To test the concept of using candles to treat PAHs in multiple runoff events, we used a flow-through system where urban runoff water was pumped over a miniature candle in repetitive wet–dry, 24-h cycles. Results showed that the candle was robust in removing PAHs by repeatedly releasing permanganate and degrading the PAHs. These results provide proof-of-concept that permanganate candles could potentially provide a low-cost, low-maintenance approach to remediating PAH-contaminated water.

Attendance Patterns and Survival of Western Meadowlark Nests

Larkin A. Powell et al. — Fri, 19 Oct 2012 07:47:50 PDT

Biologists have linked nest attendance and nestling feeding rates to nest predation risk. Patterns of nest attendance also influence the success of methods designed to find nests for research use, such as rope drags. Very little has been published with regard to variation of attendance during the nesting period, but advances in video nest monitoring allow continuous data collection to provide this information. Our objectives were to (1) document attendance patterns at Western Meadowlark (Stumella neglecta) nests, (2) identify predator species of meadowlark nests, and (3) assess the effects of our camera system on nest survival. We used a solar-powered, digital video-recording system with infrared-capable cameras to monitor nests at the Gudmundsen Sandhills Laboratory in the Nebraska Sandhills during 2006. We assessed video from 10 meadowlark nests to record nest attendance data, and we monitored 37 additional meadowlark nests to estimate survival for nests without a camera observation system. Meadowlark females spent more time at the nest during incubation than during the nestling stage. The proportion of time absent did not vary among daytime temporal segments during either nest stage. Females were absent, as a proportion of time, 0.24 during the day and 0.04 during the night throughout incubation, and 0.66 and 0.13, respectively, during the nestling stage. We documented three types of predators, and we found no evidence of negative effects of nest cameras on estimates of daily nest survival. The attendance patterns we observed may contribute to temporal trends observed in daily nest survival of grassland birds. Nest cameras are a tool that can effectively contribute information to benefit efforts to improve productivity of grassland birds

A continuous measure of gross primary production for the conterminous United States derived from MODIS and AmeriFlux data

Jingfeng Xiao et al. — Tue, 16 Oct 2012 11:29:24 PDT

The quantification of carbon fluxes between the terrestrial biosphere and the atmosphere is of scientific importance and also relevant to climate-policy making. Eddy covariance flux towers provide continuous measurements of ecosystem-level exchange of carbon dioxide spanning diurnal, synoptic, seasonal, and interannual time scales. However, these measurements only represent the fluxes at the scale of the tower footprint. Here we used remotely sensed data from the Moderate Resolution Imaging Spectroradiometer (MODIS) to upscale gross primary productivity (GPP) data from eddy covariance flux towers to the continental scale. We first combined GPP and MODIS data for 42 AmeriFlux towers encompassing a wide range of ecosystem and climate types to develop a predictive GPP model using a regression tree approach. The predictive model was trained using observed GPP over the period 2000–2004, and was validated using observed GPP over the period 2005–2006 and leave-one-out cross-validation. Our model predicted GPP fairly well at the site level. We then used the model to estimate GPP for each 1 km×1 km cell across the U.S. for each 8-day interval over the period from February 2000 to December 2006 using MODIS data. Our GPP estimates provide a spatially and temporally continuous measure of gross primary production for the U.S. that is a highly constrained by eddy covariance flux data. Our study demonstrated that our empirical approach is effective for upscaling eddy flux GPP data to the continental scale and producing continuous GPP estimates across multiple biomes. With these estimates, we then examined the patterns, magnitude, and interannual variability of GPP. We estimated a gross carbon uptake between 6.91 and 7.33 Pg C yr⁻¹ for the conterminous U.S. Drought, fires, and hurricanes reduced annual GPP at regional scales and could have a significant impact on the U.S. net ecosystem carbon exchange. The sources of the interannual variability of U.S. GPP were dominated by these extreme climate events and disturbances.

The North American Drought Monitor: A Continental Approach

Mark Svoboda — Tue, 16 Oct 2012 11:02:01 PDT

The U.S. Drought Monitor

Since 1999, NOAA (CPC and NCDC), USDA, and the NDMC have produced a weekly composite drought map -- the U.S. Drought Monitor -- with input from numerous federal and non-federal partners.

History of the North American Drought Monitor (NADM)

The concept for the NADM was developed and discussed in 2002
The first NADM map was released in March 2003
The first NADM map in all three languages (English, Spanish, and French)was released in October 2003

History of the NADM

The United States started off as the only country to author and organize the map
Canada began authoring in January 2006
Mexico began authoring in October 2008

North American Drought Monitor Partners

Canada

Agriculture and Agrifood Canada
Environment Canada
Meteorological Service of Canada

Mexico

National Meteorological Service of Mexico (SMN-Servicio Meteorologico Nacional)
CONAGUA (Comision Nacional del Agua)

United States

National Drought Mitigation Center
National Climatic Data Center
Climate Prediction Center
United States Department of Agriculture

Operational MERIS-based NIR-red algorithms for estimating chlorophyll-a concentrations in coastal waters — The Azov Sea case study

Wesley J. Moses et al. — Tue, 16 Oct 2012 10:56:47 PDT

We present here results that strongly support the use of MERIS-based NIR-red algorithms as standard tools for estimating chlorophyll-a (chl-a) concentration in turbid productive waters. The study was carried out as one of the steps in testing the potential of the universal applicability of previously developed NIR-red algorithms, which were earlier calibrated using a limited set of MERIS imagery and in situ data from the Azov Sea and the Taganrog Bay, Russia, and data that were synthetically generated using a radiative transfer model. We used an extensive set of MERIS imagery and in situ data collected over a period of three years in the Azov Sea and the Taganrog Bay for this validation task. We found that the two-band and three-band NIR-red algorithms gave consistently highly accurate estimates of chl-a concentration, with a mean absolute error of 4.32 mg m⁻³ and 4.71 mg m⁻³, respectively, and a root mean square error as low as 5.92 mg m⁻³, for data with chl-a concentrations ranging from 1.09 mg m⁻³ to 107.82 mg m⁻³. This obviates the need for case-specific reparameterization of the algorithms, as long as the specific absorption coefficient of phytoplankton in the water does not change drastically, and presents a strong case for the use of NIR-red algorithms as standard algorithms that can be routinely applied for near-real-time quantitative monitoring of chl-a concentration in the Azov Sea and the Taganrog Bay, and potentially elsewhere, which will be a real boon to ecologists, natural resource managers and environmental decision-makers.

Understanding Weather, Climate, and Birthweight: Findings from the U.S. Natility Data Files 1969-78

Ge Lin et al. — Tue, 16 Oct 2012 10:47:54 PDT

Weather and extreme weather events are thought to be related to low birth weight. If this relation is held, it will have a wide range of public health impacts as birth weight is a key indicator of many life course health outcomes, and climate change increases the intensity of extreme weather events. The current study examines the relationship between birth weight and weather variables during the birth month while controlling other known risk factors. While the preliminary results seem to suggest a relationship between birth weight and extreme hot temperature, the result does not hold when individual and other risk factors are introduced. It is concluded that birth weight is primarily related to the temperature of birth month: the colder the month, the heavier the baby, to some degree. Even though we did not confirm the relationship between birth weight and extreme weather events, global warming is still likely to negatively affect birth outcomes.

Fluctuation of Hyporheic Zone Thickness Due to Inflow and Outflow across the Water-sediment Interface

Xunhong Chen — Tue, 16 Oct 2012 10:43:17 PDT

Determination of hyporheic zone thickness in streams is an important step for study of stream-aquifer interactions. Knowledge about hyporheic zone thickness is useful in stream restoration. However, because there is a lack of standard techniques for such study, evaluation of the hyporheic zone thickness for a given stream reach remains a challenge task for researchers. This paper presents Galerkin finite element flow and stream function models that can simulate the hyporheic zone thickness. The flow and stream function equations are solved for 2-D profile domains that can be across a stream or parallel to a stream. The numeral schemes for solving the flow and stream function equations and the treatment of boundary conditions are described. Hypothetical streams are used for simulation of the control of hyporheic zone thickness by the magnitude of inflow and outflow that occur at the stream-sediment interface. Groundwater flow velocity field is generated to examine the flow dynamics in hyporheic zones. The magnitude of groundwater flow velocity in hyporheic zone is greater than that of regional groundwater flow.

Post-disaster assessment of northeastern coastal region for the 2011 Sendai Earthquake and tsunami

Ruopu Li et al. — Mon, 15 Oct 2012 07:20:26 PDT

The 2011 Sendai Earthquake has hit the north-east of Japan triggering a destructive tsunami that has caused extensive damage. A fast and effective post-disaster assessment is highly imperative for the recovery of this region. This study modeled the tsunami-affected areas of coastal Fukushima Prefecture using Landsat-7 ETM+ data and terrain analysis. The result shows that most of the coastal areas were significantly affected by the tsunami. The low-lying plains along the coast are particularly vulnerable to the tsunami.

Tracking large carnivore dispersal using isotopic clues in claws: An application to cougars across the Great Plains

Viviane Hénaux et al. — Mon, 08 Oct 2012 14:25:12 PDT

1. Cougar (Puma concolor) populations, like other large carnivores, have increased during recent decades and may be recolonizing their former ranges in Midwestern North America. The dispersal routes taken by these animals from established populations are unknown and insight into these movements would facilitate their conservation and management.

2. We inferred the origin and migration route of four dispersing cougars using stable hydrogen (δD) and carbon (δ¹³C) isotope values along one of their claws. We compared isotopic variations within claws to regional and large-scale isoscapes of δD and δ¹³C values in prey species. Using a likelihood-based assignment approach, we predicted the most likely dispersal route of each cougar (among several least-cost dispersal paths to potential source populations) in a chronological sequence dating back from its final location.

3. Our model predicted the origin of a radio-collared short-distance disperser and inferences about the most likely dispersal corridors for two long-distance dispersers matched reported information from re-sighting events and genetic investigations.

4. Insights about the most likely migration corridors may help identify critical areas and guide future conservation efforts of cougars and other large carnivores. We encourage managers to extend regional isoscapes based on sedentary prey species as they prove to be valuable tools in isotopic tracking of long-distance migration.

5. Our isotopic approach may be extended to other metabolically inert tissues that grow continuously, to investigate dispersal paths of species of interest, providing that individuals disperse across known isotopically structured landscapes.

Detecting Spatiotemporal Changes of Corn Developmental Stages in the U.S. Corn Belt Using MODIS WDRVI Data

Toshihiro Sakamoto et al. — Fri, 05 Oct 2012 07:35:31 PDT

The dates of crop developmental stages are important variables for many applications including assessment of the impact of abnormal weather on crop yield. Time-series 250-m vegetation-index (VI) data acquired from the Moderate Resolution Imaging Spectroradiometer (MODIS) provide valuable information for monitoring the spatiotemporal changes of corn growth across large geographic areas. The goal of this study is to evaluate the performance of a new crop phenology detection method, namely, two-step filtering (TSF), for revealing the spatiotemporal pattern of specific corn developmental stages (early vegetative: V2.5; silking: R1; dent: R5; mature: R6) over an eight-year period (2001–2008) across Iowa, Illinois, and Indiana using MODIS derived Wide Dynamic Range VI data. Weekly crop progress reports produced by the U.S. Department of Agriculture National Agricultural Statistics Service (NASS) were used to assess the accuracy of TSF-based estimates of corn developmental stages. The results showed that the corn developmental stages could be estimated with high accuracy (the root mean squared error ranged from 4.1 to 5.5 days, the determination coefficient ranged from 0.66 to 0.84, and the coefficient of variation ranged from 2.1% to 3.7%) based on NASS-derived statistics on an agricultural statistics district level. In particular, the annual changes in the spatiotemporal patterns of the estimated silking stage had a high level of agreement with those of the NASS-derived statistics. These results suggested that the TSF method could provide local-scale information of corn phenological stages, which had an advantage over the NASS-derived statistics particularly in terms of the spatial resolution.

Spring home ranges of white bass in irrigation reservoirs of the Republican River Basin, Nebraska

D. R. Martin et al. — Fri, 05 Oct 2012 07:33:02 PDT

Fishery biologists have documented small home ranges, relative to available habitat, for many littoral freshwater fishes. Home ranges for pelagic species, such as white bass Morone chrysops, are generally not well described, yet are thought to be large. We studied white bass movement using acoustic telemetry in two irrigation reservoirs of the Republican River basin in south-western Nebraska. Acoustic transmitters were implanted in fall of the previous year and tracking occurred a minimum of once per week throughout spring (mid-March to May) 2007 and 2008. Linear home ranges were calculated from observed locations of individual fish. Twelve of the twenty-seven tagged fish with at least five locations exhibited localised home ranges throughout the spring whereas the remaining fish exhibited home ranges extending across large portions of each reservoir. Home range size was not correlated with fish size or condition.

Nest survival of Long-billed Curlew in Nebraska

Stephen J. Dinsmore et al. — Fri, 05 Oct 2012 07:30:53 PDT

Long-billed Curlew Numenius americanus is an imperiled shorebird of western North America. Populations have declined dramatically in the last 150 years from the conversion of prairie to agriculture and it is now listed as a “Tier I at-risk” species in Nebraska. We undertook a 3-year project (2008–2010) to study the nest survival of Long-billed Curlews in Nebraska. We measured vegetation characteristics at each nest site (n = 14 nests) on two different spatial scales and used program MARK to model nest survival as a function of multiple covariates. Apparent nest survival was 29% (n = 4 successful nests) and our model-based estimate of nest survival was 33% (95% CL: 24%, 93%). This estimate is similar to other estimates of curlew nest survival in Nevada (31%) and South Dakota (15% to 39%). Visual obstruction reading height (β_o.vor = –4.17, 95% CL: –7.58, –0.77) and forb cover at the nest (β_forb = –12.49, 95% CL: –26.14, 1.17) negatively affected survival. Bare ground cover positively affected nest survival (β_bare = 3.28, 95% CL: –1.03, 7.59), but we found no evidence that nest age, grass cover, or litter depth affected nest survival. These findings suggest that Long-billed Curlews in Nebraska have a relatively low nest survival rate, but it is within the expected range for the species. Furthermore, nest survival is affected negatively by tall vegetation and forb cover at and near the nest.