Managing Vegetation in Grasslands Habitats to Meet Livestock or Wildlife Objectives

Sustainably stewarding grassland systems involves applying various practices to manipulate forage interactions with other plants, the environment, and grazing animals to meet resource manager objectives. These interactions can result in invasion or encroachment and increased abundance of weeds which hinder attainment of management objectives. Weeds influence the structure and function of pasture ecosystems whether forages are grown in improved pastures, rangeland, or grassland communities. They degrade pasture quality and reduce livestock performance by interfering with forage establishment, yield, and quality by competing for resources. Weeds reduce the feed value of forage, decrease pasture carrying capacity, and can be toxic or unpalatable to livestock. Managing weeds requires use of vegetation management tools that favor desirable forages. Herbicides can be catalysts that expedite grassland renovation, improve the forage resource, and increase carrying capacity. Corteva Agriscience has a variety of herbicide products that provide superior control of herbaceous and woody weeds, while maintaining the desirable vegetation. These herbicides were designed and developed specifically for selective broadleaf weed control in rangeland, pastures, rights-of-way, non-cropland, and natural areas. Active ingredients historically used include aminopyralid, triclopyr, fluroxypyr, clopyralid, and picloram. Rinskor™ active and Arylex™ active are new herbicide active ingredients from Corteva Agriscience™ and are members of a unique synthetic auxin chemotype, the arylpicolinates (HRAC group O / WSSA group 4). Members of the arylpicolinate family demonstrate novel and differentiated characteristics in terms of use rate, spectrum, weed symptoms, environmental fate, and molecular interaction as compared to other auxin chemotypes. When applied as a stand-alone treatment or in various mixes these products are safe to desirable grass species and control key herbaceous and woody weeds in the genera Ambrosia, Acacia, Carduus, Centaurea, Cirsium, Mimosa, Prosopis, Ranunculus, Rumex, Sida, Solanum, Taraxacum, and more

The Influences of Human Activities on the Waters of the Pecos Basin of Texas: A Brief Overview

The Pecos River in Texas is challenged by natural conditions and human influences, including a lack of water and elevated levels of salinity. The Pecos River has provided West Texas and Southeastern New Mexico an invaluable source of water for thousands of years allowing plants, animals, and humans to survive the harsh environment. The Trans-Pecos region generally marks the southwestern boundary of the Great Plains and the northeastern fringe of the Chihuahuan Desert. The Pecos River flows 926 miles through Texas and New Mexico draining a 38,000-square mile watershed (Huser, 2000; Graves, 2002; Horgan, 1984). The river flows approximately 418 miles through Texas and is the United States’ largest tributary to the Rio Grande. According to the 2006 Far West Texas Regional Water Plan (LBG-Guyton, 2006), the Pecos River contributes roughly 11% of the flows in the Rio Grande entering Lake Amistad. Salinity from natural sources enters the river at many points, compromising water quality (Miyamoto et al., 2005; Miyamoto, 1996; Miyamoto, 1995). The Pecos River is estimated to contribute roughly 30% of the annual salt loadings to Lake Amistad (LBG-Guyton, 2006). The Pecos River has been profoundly affected over time by the way humans use the river. Native Americans relied on the waters of the Pecos River as a source of fresh water even though some sections of the river were salty and foul-tasting. The river and occasional springs were the only sources of fresh water in the region. Spanish explorers and frontier cattlemen also used the Pecos River as a source of drinking water for humans, horses and cattle. Although it is difficult to know the condition of the Pecos River of Texas as it existed before American settlement, some early accounts suggest that the river ranged from 65 to 100 feet wide and 7 to 10 feet deep with a fast current (Huser, 2000; Hall 2002). Now the river is rarely, if ever, that wide or deep under normal flow conditions. Dams and pumping water for irrigation have significantly altered the natural flow of the river. In a turn-of-the-century report submitted to the Governor of Texas (Hollingsworth, 1892), conditions in the Pecos River were described in a way that reflects the natural resources dilemma still facing the region: The want of rain in seasonable time is no doubt the principal reason that millions of acres of fertile soil are not utilized at all…Cattle, sheep, and horses…not only suffer, but in many localities frequently die for want of water and grass…We have to meet the questions, can anything be done to utilize the public lands of Trans-Pecos Texas and what can or must be done?...We have to consider that millions of acres of land with fertile soil are nearly valueless, if no provisions for irrigation are made. By the late 1800s, American settlers began to develop the region for irrigation believing that the waters of the Pecos could support widespread agricultural production (Baggett, 1942; Bogener, 2003; Hayter, 1986). Throughout the Pecos Basin, many irrigation companies were created to attract settlers hoping to make a living by growing irrigated crops. Optimistic developers promoted irrigation projects with such grandiose names as Imperial and Royalty. Sadly, in many instances these attempts to create irrigated oases died quickly due to droughts and occasional floods. The creation of Red Bluff Dam in the 1930s seemingly had the potential to harness the Pecos River and provide a steady water supply for the people of West Texas. The reservoir has succeeded in storing water for irrigation, but has been plagued by managerial and water quality challenges (Hall, 2002). The Pecos River Compact was enacted between Texas and New Mexico after Red Bluff was built to ensure that Texas would receive a fair proportion of Pecos River waters each year based on the amount of rainfall runoff that occurred in New Mexico. In 1987, the U.S. Supreme Court ruled that from 1950 to 1983 New Mexico’s water deliveries to Texas were 340,100 acre-feet (AF) less than the amount of water required under the compact. More recently, New Mexico water deliveries have increased to meet the demands of the Compact and more water is being released from Red Bluff Reservoir. New Mexico currently maintains a surplus of water stored in the reservoir. The Pecos Basin of Texas is afflicted with major natural resources challenges. First, non-native saltcedar trees, introduced to the region to stabilize stream banks, now proliferate throughout the banks of the Pecos River. Saltcedars consume sizeable amounts of water, choke out native vegetation in riparian areas and increase salt loadings by drawing salts from below ground and depositing them on the surface in leaf litter (Belzer & Hart, 2006; Hart et al., 2005). Second, salts enter the river from natural deposits dissolved in rocks near Malaga Bend in southern New Mexico and between Grandfalls and Girvin, thus reducing the river’s quality (Boghici et al., 1999; LBGGuyton, 2003). Finally, the flows of the Pecos River are often not sufficient to support large-scale irrigation attempted in the past and present (Hall, 2002; Hill, 1965). To find solutions to these challenges, the Pecos Basin Assessment Program was established in 2005 to develop innovative strategies to manage water resources in the region (Figure 1). The project, led by Texas Cooperative Extension in Fort Stockton, is developing a watershed protection plan for the Pecos Basin of Texas (Hart et al., 2005). Program activities involve identifying sources of salinity, modeling the flow of the river, and determining the extent to which clearing saltcedar might increase flows in the region

Managing Vegetation In Grassland Habitats To Enhance Livestock Or Wildlife Objectives

Sustainably stewarding grassland systems involves applying various practices to manipulate forage interactions with other plants, the environment, and grazing animals to meet resource manager objectives. These interactions can result in invasion or encroachment and increased abundance of weeds which hinder attainment of management objectives. Weeds influence the structure and function of pasture ecosystems whether forages are grown in improved pastures, rangeland, or grassland communities. They degrade pasture quality and reduce livestock performance by interfering with forage establishment, yield, and quality by competing for resources. Weeds reduce the feed value of forage, decrease pasture carrying capacity, and can be toxic or unpalatable to livestock. Managing weeds requires use of vegetation management tools that favor desirable forages. Herbicides can be a catalyst that expedite grassland renovation, improve the forage resource, and increase carrying capacity. Corteva Agriscience has a variety of herbicide products that provide superior control of herbaceous and woody weeds, while maintaining the desirable vegetation. These herbicides were designed and developed specifically for selective broadleaf weed control in rangeland, pastures, rights-of-way, non-cropland, and natural areas. Active ingredients historically used include aminopyralid, triclopyr, fluroxypyr, clopyralid, and picloram. Rinskor™ active and Arylex™ active are new herbicide active ingredients from Corteva Agriscience™ and are members of a unique synthetic auxin chemotype, the arylpicolinates (HRAC group O / WSSA group 4). Members of the arylpicolinate family demonstrate novel and differentiated characteristics in terms of use rate, spectrum, weed symptoms, environmental fate, and molecular interaction as compared to other auxin chemotypes. When applied as a stand-alone treatment or in various mixes these products are safe to desirable grass species and control key herbaceous and woody weeds in the genera Ambrosia, Acacia, Carduus, Centaurea, Cirsium, Mimosa, Prosopis, Ranunculus, Rumex, Sida, Solanum, Taraxacum, and more

Quantity and Fate of Water Salvage as a Result of Saltcedar Control on the Pecos River in Texas

This report presents results for the Subtask 3.3 of the Pecos River Basin Assessment Project sponsored by the U.S. Environmental Protection Agency (EPA) and the Texas State Soil and Water Conservation Board (TSSWCB). The overall objective of Subtask 3.3 is to examine the hydrologic impacts of Tamarix spp. (saltcedar) control along a 5 km segment of the Pecos River near Mentone, Texas. This report is also based on work supported in part by the Cooperative State Research, Education, and Extension Service, U.S. Department of Agriculture, under Agreements No. 2005-34461-15661 and No. 2005-45049-03209, Texas Cooperative Extension (TCE), and Texas Agricultural Experiment Station (TAES). As part of the deliverables of this project, an existing monitoring network of 8 wells was examined and enhanced with 9 additional wells equipped with water level loggers. Land surface profile and piezometric surface profile were developed to characterize interaction of surface and groundwater for different seasons as well as for verification of monitored water levels. Flow measurements were conducted during a release of water from Red Bluff Reservoir in March 2005 to determine losses or gains within the selected reach. Continued water level monitoring data provide more detailed information about water exchange between surface water and groundwater under different flow conditions. Correlation analyses of river stage and groundwater levels in monitoring boreholes provided further insight. Results show that the river is hydraulically connected with shallow groundwater for this 5 km segment, which is comprised of Sites A and B, near Mentone, Texas in Loving County. Generally, the river is losing water to the aquifer at both sites. A gentle hydraulic gradient exists on the east bank of the river while a steeper gradient occurs on the west bank probably due to different hydrological properties of soils. Seepage from the river not only recharges the shallow aquifer, but also creates groundwater flow parallel to the channel, which may eventually discharge back to the river downstream. The reversed hydraulic gradients also demonstrate complexity of the dynamic relationship between the river and the aquifer. Water loss at the treated Site A decreased dramatically following saltcedar control in 2001, and remained very low through 2004. This study conservatively estimates water salvage of 0.5 – 1.0 acre feet per acre from control of saltcedar at this particular site. Salvaged water most likely contributes to aquifer recharge rather than increased streamflow. Vegetation return in the form of native grasses and saltcedar re-growth at Site A may be the cause of corresponding increases in water loss in 2005 and 2006. Site A may also be affected by the untreated adjacent upriver segment (Site B), resulting in over-estimated water loss. Although the saltcedar water loss and salvage estimates presented here are believed to be conservative, the extreme differences in yearly site conditions throughout the study made it difficult to compare pre and post treatment calculations with confidence. It is recommended that additional flow measurements for longer reaches, enhanced monitoring of surface water and groundwater interaction, and further studies on hydrological impacts of saltcedar control be conducted. For future studies using the paired plot method, it is recommended that both sites be logged for at least 3 years prior to treatment. To reduce the potential for upriver treatment affect on downriver study areas, it is recommended that hydrological and ecological conditions immediately upstream of each plot be alike.U.S. Environmental Protection Agency and the Texas State Soil and Water Conservation Boar

Salmonid species diversity predicts salmon consumption by terrestrial wildlife

1. Resource waves—spatial variation in resource phenology that extends feeding opportunities for mobile consumers—can affect the behaviour and productivity of recipient populations. Interspecific diversity among Pacific salmon species (Oncorhynchus spp.) creates staggered spawning events across space and time, thereby prolonging availability to terrestrial wildlife. 2. We sought to understand how such variation might influence consumption by terrestrial predators compared with resource abundance and intra- and interspecific competition. 3. Using stable isotope analysis, we investigated how the proportion of salmon in the annual diet of male black bears (Ursus americanus; n = 405) varies with species diversity and density of spawning salmon biomass, while also accounting for competition with sympatric black and grizzly bears (U. arctos horribilis), in coastal British Columbia, Canada. 4. We found that the proportion of salmon in the annual diet of black bears was ≈40% higher in the absence of grizzly bears, but detected little effect of relative black bear density and salmon biomass density. Rather, salmon diversity had the largest positive effect on consumption. On average, increasing diversity from one salmon species to ~four (with equal biomass contributions) approximately triples the proportion of salmon in diet. 5. Given the importance of salmon to bear life histories, this work provides early empirical support for how resource waves may increase the productivity of consumers at population and landscape scales. Accordingly, terrestrial wildlife management might consider maintaining not only salmon abundance but also diversit

Abundance, behavior, and movement patterns of western gray whales in relation to a 3-D seismic survey, Northeast Sakhalin Island, Russia

A geophysical seismic survey was conducted in the summer of 2001 off the northeastern coast of Sakhalin Island, Russia. The area of seismic exploration was immediately adjacent to the Piltun feeding grounds of the endangered western gray whale (Eschrichtius robustus). This study investigates relative abundance, behavior, and movement patterns of gray whales in relation to occurrence and proximity to the seismic survey by employing scan sampling, focal follow, and theodolite tracking methodologies. These data were analyzed in relation to temporal, environmental, and seismic related variables to evaluate potential disturbance reactions of gray whales to the seismic survey. The relative numbers of whales and pods recorded from five shore-based stations were not significantly different during periods when seismic surveys were occurring compared to periods when no seismic surveys were occurring and to the post-seismic period. Univariate analyses indicated no significant statistical correlation between seismic survey variables and any of the eleven movement and behavior variables. Multiple regression analyses indicated that, after accounting for temporal and environmental variables, 6 of 11 movement and behavior variables (linearity, acceleration, mean direction, blows per surfacing, and surface-dive blow rate) were not significantly associated with seismic survey variables, and 5 of 11 variables (leg speed, reorientation rate, distance-from-shore, blow interval, and dive time) were significantly associated with seismic survey variables. In summary, after accounting for environmental variables, no correlation was found between seismic survey variables and the linearity of whale movements, changes in whale swimming speed between theodolite fixes, mean direction of whale movement, mean number of whale exhalations per minute at the surface, mean time at the surface, and mean number of exhalations per minute during a whales surface-to-dive cycle. In contrast, at higher received sound energy exposure levels, whales traveled faster, changed directions of movement less, were recorded further from shore, and stayed under water longer between respirations

Somatic Mutagenesis with a Sleeping Beauty Transposon System Leads to Solid Tumor Formation in Zebrafish

Large-scale sequencing of human cancer genomes and mouse transposon-induced tumors has identified a vast number of genes mutated in different cancers. One of the outstanding challenges in this field is to determine which genes, when mutated, contribute to cellular transformation and tumor progression. To identify new and conserved genes that drive tumorigenesis we have developed a novel cancer model in a distantly related vertebrate species, the zebrafish, Danio rerio. The Sleeping Beauty (SB) T2/Onc transposon system was adapted for somatic mutagenesis in zebrafish. The carp ß-actin promoter was cloned into T2/Onc to create T2/OncZ. Two transgenic zebrafish lines that contain large concatemers of T2/OncZ were isolated by injection of linear DNA into the zebrafish embryo. The T2/OncZ transposons were mobilized throughout the zebrafish genome from the transgene array by injecting SB11 transposase RNA at the 1-cell stage. Alternatively, the T2/OncZ zebrafish were crossed to a transgenic line that constitutively expresses SB11 transposase. T2/OncZ transposon integration sites were cloned by ligation-mediated PCR and sequenced on a Genome Analyzer II. Between 700–6800 unique integration events in individual fish were mapped to the zebrafish genome. The data show that introduction of transposase by transgene expression or RNA injection results in an even distribution of transposon re-integration events across the zebrafish genome. SB11 mRNA injection resulted in neoplasms in 10% of adult fish at ∼10 months of age. T2/OncZ-induced zebrafish tumors contain many mutated genes in common with human and mouse cancer genes. These analyses validate our mutagenesis approach and provide additional support for the involvement of these genes in human cancers. The zebrafish T2/OncZ cancer model will be useful for identifying novel and conserved genetic drivers of human cancers