SP704-A Potential Impacts on Wildlife of Switchgrass Grown for Biofuels

Version 3.

SP704-A Potential Impacts on Wildlife of Switchgrass Grown for Biofuels

Version 3.

Northern Bobwhite Survival, Nest Success, and Habitat Use in Kentucky During the Breeding Season

Northern bobwhite (Colinus virginianus) populations have experienced protracted declines over much of their range. There has been an annual decrease of 2.61% since the 1960s in Kentucky, an area representative of the Mid-South where there is a lack of data on basic population parameters. Much of the decline is attributed to prevailing land-use practices and associated habitat loss. We monitored northern bobwhite on a 515-ha farm in Oldham County, Kentucky to assess survival rates, nest success rates, and habitat use in the Mid- South. The farm consisted of row crops, cool-season pastures and hay (primarily tall fescue), fallow native warm-season grass fields, and woods. We captured birds using baited funnel traps and fitted them with harness radio transmitters and monitored them daily during April–August, 2009 and 2010. We radiomarked 88 birds (40 females, 48 males) and monitored 24 nests, 9 (37.5%) of which were successful, over the 2 years. Survival rates were 25.3 and 27.9% for 2009 and 2010, respectively, based on estimates from Program MARK. Home range size (54.0, range 1⁄4 38.0–55.9 ha) did not differ by sex, age, or year (P .0.05). Quail favored food plots in both years and avoided developed areas

Songbird breeding season use of pine plantations treated chemically for herbaceous vegetation control

Pine plantations, a common early successional habitat in the southeastern United States, have been subject in recent years to increased use of herbicides to control herbaceous vegetation immediately postestablishment. Such treatments may affect songbird use during the breeding season, but studies documenting bird response are limited. Furthermore, songbirds that breed in early successional habitats have experienced sustained population declines in recent decades. Therefore, we examined the influence of herbaceous vegetation control on songbird use during the breeding season within pine plantations on the Piedmont Plateau in Virginia. We evaluated 35 plantations characterized by one of five treatments: herbaceous vegetation control applied during the establishment year and that were 1, 2, or 3 y old when sampled, and those that had not received herbaceous vegetation control at establishment and that were 1 or 2 y old when sampled. There was no difference (P . 0.05) in detections of birds between plantations with and without herbicide treatment. However, 1-y-old plantations (both treated and untreated) had fewer detections (P , 0.05) than 2-y-old plantations for 3 individual species and for all 16 species combined

Prescribed Fire Impacts to Amphibians and Reptiles in Shelterwood-harvested Oak-dominated Forests

As part of a larger study examining the role of prescribed fire in regenerating upland oaks (Quercus spp.), seasonal prescribed burns (winter, spring, summer, and unburned control) were applied to first-stage shelterwood-harvested stands on Horsepen Wildlife Management Area in the Virginia Piedmont in 1995. Because fire impacts are poorly documented for herpetofaunal communities, we surveyed these stands in 1996 capturing 133 individuals of ten species during over 12,720 pitfall trapnights. We found no significant differences in relative abundance of Eastern Red-backed Salamanders (Plethodon cinereus) (P = 0.26), American Toads (Bufo americanus) (P = 0.93), or all amphibians combined (P = 0.25) among unburned shelterwood stands and those treated with winter, spring, or summer burns. Three species of reptiles (Northern Fence Lizard [Sceloporus undulatus], Ground Skink [Scincella lateralis], and Southeastern Five-lined Skink [Eumeces inexpectatus]) combined were captured more frequently in burned versus unburned stands (P = 0.02). Based on a stepwise multiple regression model, Eastern Red-backed Salamander captures were more strongly influenced by landscape variables (P = 0.0320), including distance to permanent water and mesic (i.e., eastern-northern) aspects, than by fire treatments (P = 0.26). Similar landscape models were not significant (P \u3c 0.05) for toads or reptiles. Based on these results, prescribed fire may not be detrimental to herpetofaunal communities in oak dominated forests in the Virginia Piedmont

Influence of Pyrolysis Temperature and Production Conditions on Switchgrass Biochar for Use as a Soil Amendment

Biochars form recalcitrant carbon and increase water and nutrient retention in soils; however, the magnitude is contingent upon production conditions and thermo-chemical conversion processes. Herein we aim at (i) characterizing switchgrass (Panicum virgatum L.)-biochar morphology, (ii) estimating water-holding capacity under increasing ratios of char: soil; and, (iii) determining nutrient profile variation as a function of pyrolysis conversion methodologies (i.e. continuous, auger pyrolysis system versus batch pyrolysis systems) for terminal use as a soil amendment. Auger system chars produced at 600 °C had the greatest lignin portion by weight among the biochars produced from the continuous system. On the other hand, a batch pyrolysis system (400 °C – 3h) yielded biochar with 73.10% lignin (12 fold increases), indicating higher recalcitrance, whereas lower production temperatures (400 °C) yielded greater hemicellulose (i.e. greater mineralization promoting substrate). Under both pyrolysis methods, increasing biochar soil application rates resulted in linear decreases in bulk density (g cm-3). Increases in auger-char (400 °C) applications increased soil water-holding capacities; however, application rates of \u3e2 Mt ha-1 are required. Pyrolysis batch chars did not influence water-holding abilities (P\u3e0.05). Biochar macro and micronutrients increased, as the pyrolysis temperature increased in the auger system from 400 to 600 °C, and the residence time increased in the batch pyrolysis system from 1 to 3 h. Conversely, nitrogen levels tended to decrease under the two previously mentioned conditions. Consequently, not all chars are inherently equal, in that varying operation systems, residence times, and production conditions greatly affect uses as a soil amendment and overall rate of efficacy

Perennial Warm-Season Grass Forages Impact on Cow-Calf Profitability in the Fescue Belt

Incorporating a perennial warm- season grass (WSG) into tall fescue (Lolium arundina-ceum [Schreb.] Darbysh.) forage systems in the fescue belt can help avoid the effects of fescue toxicosis on beef cattle (Bos taurus) reproduction and animal performance and provide forage during summer when fescue production is low. However, little information is available on the economics of incorporating WSG into fescue-based forage systems. We developed a simulation model to compare profitability of three forage systems—100% tall fescue, 70% tall fescue/30% bermudagrass (Cynodon dactylon), and 70% tall fescue/ 30% switchgrass (Panicum virgatum)—while also comparing spring- and fall-calving sea-sons on model beef cattle cow-calf operations in the fescue belt. Incorporating switch-grass increased profitability of tall fescue forage systems in both spring- and fall- calving herds, while adding bermudagrass increased profitability in spring-calving herds but not fall-calving herds. Spring-calving herds benefited the most from incorporating WSG, with profitability increases of $877 and$372 per hectare for switchgrass and bermudagrass, respectively, over the 100% tall fescue system. The order of profitability of forage systems did not change with randomly simulated decreases in rainfall and associated increased hay- feeding days, but with annual rainfall \u3e88% of the long- term average, fall- calving 100% tall fescue was more profitable than fall- calving 70% tall fescue/30% bermuda grass. Of the scenarios modeled, the results of the simulation suggest that a profit-maximizing producer would utilize a 70% tall fescue/30% switchgrass forage system

Northern Bobwhite Survival Related to Movement on a Reclaimed Surface Coal Mine

Reclaimed coal mines represent opportunity to provide large tracts of early succession habitat essential to northern bobwhite (Colinus virginianus) populations. However, little research has been conducted to explore the potential of reclaimed mine sites and examine bobwhite ecology on these unique areas. Reclaimed mines in Kentucky were planted to non-native species, such as sericea lespedeza (Lespedeza cuneata) and tall fescue (Festuca arundinacea), which do not provide suitable structure for northern bobwhite brood-rearing and movement. Fallow disking (in blocks and linear firebreaks) and planting food plots are part of current management efforts to improve food availability and habitat structure for broods. We trapped and radiomarked 266 northern bobwhites between April 2010 and September 2011 on Peabody Wildlife Management Area, a 3,330-ha reclaimed coal mine in western Kentucky, USA to investigate the effects of current management practices on movement and survival. We calculated seasonal daily movement as the Euclidean distance from a location on day 1 to day 2. Breeding season (1 Apr-30 Sep) movement averaged 128 m in 2010 and 147 m in 2011. Daily movement averaged 163 m during the 2010–2011 non-breeding (1 Oct-31 Mar) season. Multiple regression analysis indicated annual food plots, disk blocks, firebreaks, and roads did not explain variation within daily movement regardless of season (R2 0.04). Individual bird/covey, precipitation, hours between locations, and average temperature also poorly explained movement variation. We used Program MARK to model the effect of season, year, mean daily movement, mean distance to annual food plots, disk blocks, firebreaks, and roads on survival. The season (breeding/non-breeding) model explained 81% of the variation in survival, and the year model explained 13%, suggesting management was not driving survival. We do not believe disking should be discontinued, although it did not influence movement, as it can improve vegetation structure important to nest-site selection and broods

Survival of Radio-Marked Versus Leg-Banded Northern Bobwhite in Kentucky

Understanding the impact of radiomarking northern bobwhite (Colinus virginianus) survival is essential because of the widespread reliance on radiotelemetry to assess vital population parameters. We conducted an assessment of bobwhite populations within the Central Hardwoods Bird Conservation Region using leg banding and radiotelemetry on Peabody Wildlife Management Area, a 3,330-ha reclaimed surface mine in western Kentucky. We captured bobwhites using baited funnel traps during a 112-day period (23 Jul-11 Nov 2010) and marked 180 with necklace-style radio-transmitters (6 g) and 256 birds with only leg bands. Eighty-five birds were opportunistically recaptured in funnel traps, of which 81 were used in developing survival estimates. We used the Cormack-Jolly-Seber model in Program MARK to estimate periodic survival rates (PSR) of both sample groups. Candidate models which included body mass as a covariate explained the most variability in survival. The estimated PSR was 0.309 6 0.109 based on the best approximating model and was 0.302 6 0.108 from model averaging. We calculated a point of inflection for this model, which suggested a mass ‘threshold’ of 131g, above which survival improved at a decreasing rate. The model including only the radio-transmitter effect had a DAICc .3 and was considered to be non-plausible. Further research with larger samples is needed to develop more robust survival models to fully assess the effects of radiomarking bobwhites. It does not appear, based on our study, that radio transmitters adversely affect survival of northern bobwhite

Nitrogen Fixation and Seeding Rates of Common vs. Hairy Vetch for Interseeding Into Established Switchgrass Stands

Interest in alternatives to synthetic nitrogen (N) fertilizer sources for switchgrass (Panicum virgatum L.) production, such as interseeding with N- fixing legumes continues to increase. Common vetch (Vicia sativa) is a N-fixing legume that occurs naturally throughout the U.S. and has less hard seed than hairy vetch (Vicia villosa), making it potentially less invasive, and it may fix N at similar rates to that of hairy vetch. However, little data exist to substantiate this. In this study, N-fixation rates via the N-difference method were determined to be 59.3 and 43.3 kg N ha-1 for common and hairy vetch, respectively, when seeded at 6.7 kg ha-1. At these rates, neither common nor hairy vetch significantly affected switchgrass yields. Based on the N-fixation rates and vetch plant masses, we estimate that minimum seeding rates of 7.6 and 10.4 kg PLS ha-1 of common and hairy vetch, respectively are required to obtain plant stands needed to fix the current recommended rate of N for switchgrass biomass production