Conservation Reserve Program research and demonstration project

This project, the first of its kind in the nation, used land enrolled in the Conservation Reserve Program to demonstrate intensive rotational grazing as an economically and environmentally viable alternative use for highly erodible land due to come out of CRP contracts beginning in 1996. A local committee secured funds and expertise from various agencies to establish three grazing systems. Forage improvement, innovative watering and fencing systems, contour lanes, and other aspects of grazing were implemented and evaluated. The project also included a field survey inventory of land in 300 CRP contracts in a three-county area. Another important segment of this five-year project involved education activities such as field days, grazing clinics, tours, and presentations both on and off the site

Demonstration and technology transfer to producers implementing sustainable rotational grazing systems

All rotational grazing systems require fences, water, and forages. This project used hands-on demonstrations to show producers some of the options available for each of these components of a successful grazing system

Education-demonstration for intensive grazing and forage management on highly erodible land

The wise use of highly erodible marginal land is an important economic and environmental issue. Rotational grazing for livestock is one method of land use improvement suitable for HEL or other cropland that needs to be converted to pasture. Using an existing demonstration farm in Adams County, Iowa, various paddock arrangements and forage varieties were tested to help farmers devise appropriate sustainable grazing systems

Allosteric Activation of the Par-6 PDZ Via a Partial Unfolding Transition

Proteins exist in a delicate balance between the native and unfolded states, where thermodynamic stability may be sacrificed to attain the flexibility required for efficient catalysis, binding, or allosteric control. Partition-defective 6 (Par-6) regulates the Par polarity complex by transmitting a GTPase signal through the Cdc42/Rac interaction binding PSD-95/Dlg/ZO-1 (CRIB-PDZ) module that alters PDZ ligand binding. Allosteric activation of the PDZ is achieved by local rearrangement of the L164 and K165 side chains to stabilize the interdomain CRIB:PDZ interface and reposition a conserved element of the ligand binding pocket. However, microsecond to millisecond dynamics measurements revealed that L164/K165 exchange requires a larger rearrangement than expected. The margin of thermodynamic stability for the PDZ domain is modest (∼3 kcal/mol) and further reduced by transient interactions with the disordered CRIB domain. Measurements of local structural stability revealed that tertiary contacts within the PDZ are disrupted by a partial unfolding transition that enables interconversion of the L/K switch. The unexpected participation of partial PDZ unfolding in the allosteric mechanism of Par-6 suggests that native-state unfolding may be essential for the function of other marginally stable proteins

DISTRIBUTION, DIET, AND PREVALENCE OF AMPHIBIAN CHYTRID FUNGUS IN NON-NATIVE AMERICAN BULLFROGS (LITHOBATES CATESBEIANUS) AT THE VALENTINE NATIONAL WILDLIFE REFUGE, NEBRASKA, USA

American Bullfrogs (Lithobates catesbeianus) have been widely introduced beyond their native range in North America and can negatively affect organisms in wetland environments via a suite of mechanisms including interspecific interactions and disease transmission. Bullfrogs were introduced to the Valentine National Wildlife Refuge in the Sandhill Region of Nebraska, USA, yet little is known regarding their distribution, abundance, and potential effects on other vertebrates in the Refuge. Surveys in 1991-1992 documented bullfrogs in only one lake by the Refuge headquarters, and anecdotal historical observations indicated that bullfrogs were present primarily in lakes open to public fishing. In 2012, we determined the distribution of bullfrogs across the Refuge, examined their diets, and sampled them for the occurrence of the pathogenic fungus, Batrachochytrium dendrobatidis. We documented that bullfrogs were almost ubiquitous across the Refuge lakes and wetlands. From diet analyses, we observed that adult bullfrogs consumed several vertebrate species on the Refuge including: a Blanding’s Turtle (Emydoidea blandingii), small bullfrogs, an unidentifiable frog species, and numerous invertebrates, including crayfish. The amphibian chytrid fungus was prevalent on the refuge with 73.7% of bullfrogs testing positive for the fungus in early June and 6.3% in late June-July. Preliminary data indicate that bullfrogs likely have already affected interspecific interactions with native amphibians via predation, competition, and/or disease transmission. Bullfrogs likely cannot be eradicated from the Refuge, but expanding the season of harvest of bullfrogs might reduce their abundance, which may benefit native amphibians and reptiles

ACCURACY OF ANTLER METRICS IN PREDICTING AGE OF WHITE-TAILED DEER AND MULE DEER

Electronic deer check systems offer state natural resource agencies alternatives to mandatory in-person check stations, resulting in potential savings in money and personnel. However, a reliable means for hunters to classify the age of harvested antlered deer must be established so that important management indices such as antlered yearling harvest can continue to be used to set future management goals. Therefore, we evaluated the use of six different antler metrics to predict age class of white-tailed and mule deer (1.5 and \u3e/= 2.5 years). We used discriminant analysis to determine the number of deer correctly classified into each age class based on the antler metric with the greatest degree of separation for each species. Of those evaluated, main beam length and inside spread were the two most accurate measurements for both species. For white-tailed deer, 93% (114 of 123) of the 1.5-year age class and 93% (251 of 271) of the \u3e/= 2.5-year age class were correctly classified using main beam length with a cutoff of 364 mm. For mule deer, 100% (12 of 12) of the 1.5-year age class and 97% (35 of 36) of the \u3e/= 2.5-year age class were correctly classified using main beam length with a cutoff of 352 mm. Antler metrics of both deer species can be used to accurately classify age class while likely saving funds and personnel hours

Genetic protocols for DNA extraction from white-tailed deer cast antlers to confirm individuality

White-tailed deer (Odocoileus virginianus) are the most sought-after deer species in America. The antlers of mammals, such as deer, are one of the fastest regenerative tissues in the world and are grown and naturally cast every year. Research on cast antlers have been used for a variety of purposes including population comparisons and impacts of deer health due to climatic stressors. When investigating cast antlers, it is important to confirm individuality of match sets in addition to antlers of the same individual between years. Therefore, individuality must be confirmed genetically, and protocols must be developed and established to do so. Our objectives were to 1) establish a genetic protocol to harvest DNA from cast antlers using connective tissue, and 2) determine individuality from subsequent years and match sets. When fresh antlers are cast, they leave behind a viable connective tissue from which DNA can be extracted. The DNA was successfully extracted from the skin rings harvested from naturally cast antlers. This study developed viable methods to confirm individuality, which aid researchers and wildlife biologists in a better understanding of the white-tailed deer herd as they set management goals and harvest regulations

Phenology of Antler Casting and Occurrence of Late-Breeding in Nebraska White-Tailed Deer

White-tailed deer (Odocoileus virginianus) in Nebraska primarily breed in November (stimulated by photoperiod), but this season extends into December and January for unfertilized females and healthy fawns reaching the appropriate breeding weight by winter. Variation in the typical mating period can be attributed to geographic region, skewed sex ratios, and fawns reaching sexual maturity during their first year of birth. During April of 2019, we observed late season breeding by a male white-tailed deer in the central Platte River valley and documented late antler casting for this same late-copulating male. An additional male was observed in April of 2020 still retaining antlers within the region. To understand the irregularity of these observations relative to the central Platte River valley, we documented observations of early and late antler casting utilizing long-term cast antler collection and camera trap data. We were able to establish a baseline for antler casting phenology within this region to denote a shift in average casting timeframe (more than one month later than previously recorded in this region) and document early and the latest known antler casting within the literature. Herein, we detail the variation in antler casting phenology for white-tailed deer in this region, and the latest known occurrence of natural breeding in the state. Our findings help us better understand the life history of the Nebraska white-tailed deer population and can assist state wildlife biologists and property managers as they assess seasonal harvest regulations and adaptively manage the changing resource