Conservation Reserve Program Fields Research Articles

Persistence and quality of vegetation cover in expired Conservation Reserve Program fields

AbstractFor nearly 40 years, the Conservation Reserve Program (CRP) has implemented practices to reduce soil erosion, improve water quality, and provide habitat for wildlife and pollinators on highly erodible cropland in the United States. However, an approximately 40,470 ha (10 million acres) decline in enrolled CRP land over the last decade has greatly reduced the program's environmental benefits. We sought to assess the program's enduring benefits in the central and western United States by (1) determining the proportion of fields that persist in CRP cover after contracts expired, (2) identifying the type of agricultural production that CRP fields shift to after contract expiration, (3) comparing the vegetation characteristics of expired CRP fields that are persisting in CRP‐type cover with enrolled CRP fields, and (4) identifying differences in management activities (e.g., haying, grazing) between expired and enrolled CRP fields. We conducted edge‐of‐field vegetation cover surveys in 1092 CRP fields with contracts that expired ≥3 years prior and 1786 currently enrolled CRP fields in 14 states. We found that 41% of expired CRP fields retained at least half of their area in CRP‐type cover, with significant variation in persistence among regions ranging from 19% to 84%. When expired fields retained CRP vegetation, bare ground was low in all regions and grass cover was somewhat greater than in fields with current CRP contracts, but at the expense of forb cover in some regions. Evidence of more frequent management in expired CRP fields may explain differences between active and expired CRP fields. Overall, there is clear evidence that CRP‐type cover frequently persists and provides benefits for more than three years after contract expiration. Retaining CRP‐type cover, post‐contract, is an under‐recognized program benefit that persists across the central and western United States long after the initial retirement from cropland.

Cattle grazing in CRP grasslands during the nesting season: effects on avian reproduction

AbstractBird populations in grasslands have experienced declines coinciding with loss and fragmentation of prairies. The United States Department of Agriculture (USDA)‐administered Conservation Reserve Program (CRP) is the most extensive grassland restoration program in North America and it has especially benefitted grassland birds. Grazing by domestic cattle has been restricted in CRP during avian nesting seasons despite the potential improvements in structuring habitat for a greater diversity of grassland bird species. Potential negative consequences of grazing in CRP grasslands include trampling of nests by cattle, reductions in nest concealment from predators, and attraction of brood‐parasitic brown‐headed cowbirds (Molothrus ater). We designed an experiment to test for effects of cattle grazing in CRP fields during the nesting season on nest survival and brood parasitism of 5 bird species that commonly nest in CRP grasslands: mourning dove (Zenaida macroura), grasshopper sparrow (Ammodramus savannarum), dickcissel (Spiza americana), and eastern (Sturnella magna) and western (S. neglecta) meadowlarks. Grazing was implemented during summers 2017 and 2018 on 17 of 36 fields followed by a year of rest on all fields in 2019. Of the 879 nests on grazed fields, only 4 were likely trampled by cattle (vs. 54% of all nests estimated as failing because of depredation). Experimental grazing (grazed vs. ungrazed fields) had variable effects on nest survival and cowbird parasitism among the bird species analyzed. Negative effects of grazing on daily nest survival of dickcissel and meadowlarks were apparent, at least in some years. We found no direct effects of grazing on nest survival of mourning dove or grasshopper sparrow. Probability and intensity (cowbird offspring/nest) of cowbird parasitism in dickcissel nests was higher on grazed versus ungrazed sites but only in conservation practice (CP) CP2 (vs. CP25 fields). Parasitism probability of grasshopper sparrow nests by cowbirds was higher on grazed fields in the 2 years after introduction of cattle in 2017. Greater vegetative concealment around nest sites was associated with reduced cowbird parasitism of meadowlark and grasshopper sparrow nests and higher nest survival for grasshopper sparrows. Reductions in vegetative height caused by longer‐term or high‐intensity grazing might therefore have negative consequences for some grassland birds by increasing nest site visibility and exposure to cowbird parasitism. Our results indicate that cattle grazing in CRP fields during the nesting season might have some negative effects on reproductive success of some grassland bird species, at least in the short term; however, the potential improvements of structuring habitat to accommodate more grassland bird species and increasing landowner participation in the CRP are considerable.

Land use decisions after the Conservation Reserve Program: Re‐enrollment, reversion, and persistence in the southern Great Plains

AbstractThe temperate grasslands of North America remain one of the most modified and threatened ecosystems on the planet. In the United States, the conservation of grassland‐dependent wildlife continues to be challenged by the widespread conversion of privately owned grasslands to cropland. Recent analyses indicate that land exiting the Conservation Reserve Program (CRP), the country's largest private lands conservation program, is a primary source of grassland conversion. In this mixed‐methods study, we employed focus groups and mail surveys to understand the decisions made by landowners in the southern Great Plains as their CRP contracts near expiration and up to 7 years following expiration. We explored both the post‐contract intentions of landowners with fields currently enrolled in CRP and the self‐reported, post‐contract decisions of landowners whose CRP contracts expired between 2011 and 2017. Interest in re‐enrolling in CRP upon contract expiration was high among landowners with current fields; however, over half of landowners with former CRP fields reported being unable to re‐enroll when they tried. We found higher rates of grassland persistence than have been previously reported, but also detected temporal patterns that suggest that cropland reversion is increasingly likely as the time since contract expiration increases. This study highlights the need for increased attention to the barriers that preclude transition into other conservation programs following CRP and more detailed understanding of what drives landowner decision‐making about re‐enrollment and post‐CRP land use. These insights will be critical for increasing the effectiveness of programs for enduring grassland conservation on private lands.

No‐till establishment improves the climate benefit of bioenergy crops on marginal grasslands

AbstractExpanding biofuel production is expected to accelerate the conversion of unmanaged marginal lands to meet biomass feedstock needs. Greenhouse gas production during conversion jeopardizes the ensuing climate benefits, but most research to date has focused only on conversion to annual crops and only following tillage. Here we report the global warming impact of converting USDA Conservation Reserve Program (CRP) grasslands to three types of bioenergy crops using no‐till (NT) vs. conventional tillage (CT). We established replicated NT and CT plots in three CRP fields planted to continuous corn, switchgrass, or restored prairie. For the 2 yr following an initial soybean year in all fields, we found that, on average, NT conversion reduced nitrous oxide (N2O) emissions by 50% and CO2 emissions by 20% compared with CT conversion. Differences were higher in Year 1 than in Year 2 in the continuous corn field, and in the two perennial systems the differences disappeared after Year 1. In all fields net CO2 emissions (as measured by eddy covariance) were positive for the first 2 yr following CT establishment, but following NT establishment net CO2 emissions were close to zero or negative, indicating net C sequestration. Overall, NT improved the global warming impact of biofuel crop establishment following CRP conversion by over 20‐fold compared with CT (−6.01 Mg CO2e ha−1 yr−1 for NT vs. −0.25 Mg CO2e ha−1 yr−1 for CT, on average). We also found that Intergovernmental Panel on Climate Change estimates of N2O emissions (as measured by static chambers) greatly underestimated actual emissions for converted fields regardless of tillage. Policies should encourage adoption of NT for converting marginal grasslands to perennial bioenergy crops to reduce C debt and maximize climate benefits.

Long‐term evapotranspiration rates for rainfed corn versus perennial bioenergy crops in a mesic landscape

AbstractPerennial cellulosic crops are promoted for their potential contributions to a sustainable energy future. However, a large‐scale perennial bioenergy production requires extensive land use changes through diversion of croplands or conversion of uncultivated lands, with potential implications for local and regional hydrology. To assess the impact of such land use conversions on ecosystem water use, we converted three 22 year‐old Conservation Reserve Program (CRP) grasslands and three 50+ year‐old conventionally tilled corn‐soybean crop fields (AGR) to either no‐till continuous maize (corn) or perennial (switchgrass or restored prairie) bioenergy crops. We also maintained one CRP grassland without conversion. We measured evapotranspiration (ET) rates on all fields for 9 years using eddy covariance methods. Results show that: (a) mean growing‐season ET rates for perennial crops were similar to the ET rate of the corn they replaced at the previously cultivated (AGR) field but ET rates for perennial crops at CRP fields were 5–9% higher than ET rate for corn on former CRP fields; and (b) mean nongrowing season ET rates for perennial fields were 11–15% lower than those for corn fields, regardless of land use history. On an annual basis, mean ET rates for perennial crops tended to be lower (4–7%) than ET rate of the corn that they replaced at AGR fields but ET rates for perennial crops and corn at CRP fields were similar. Over 9 years, mean ET rates for the same crop across land use histories were remarkably similar for corn, whereas for the perennial crops they were 4–10% higher at former CRP than at former AGR fields, mainly due to differences in growing season ET. Over the 9 years and across all fields, ET returned ~60% of the precipitation back to the atmosphere. These findings suggest that large‐scale substitution of perennial bioenergy crops for rainfed corn in mesic landscapes would have little if any (0 to −3%) impact on terrestrial water balances.

Columbian sharp‐tailed grouse nesting ecology: wind energy and habitat

ABSTRACTThe rapid pace of wind‐energy development has increased stakeholder concerns regarding the potential effects on wildlife. Locations targeted for wind‐energy development frequently overlap prairie grouse and greater sage‐grouse (Centrocercus urophasianus) habitats. Research suggests that anthropogenic developments may have negative effects on these species. There is, however, no information published regarding the effect of wind‐energy development on Columbian sharp‐tailed grouse (Tympanuchus phasianellus columbianus), a subspecies that has twice been petitioned for Endangered Species Act protection. To address this need, from 2014 to 2015 we studied Columbian sharp‐tailed grouse nesting ecology across restored grasslands in eastern Idaho, USA, where a 215‐turbine wind‐energy complex had been developed. We monitored 147 nests from 135 females captured at leks 0.1–13.8 km from wind turbines. We used an information‐theoretic approach to evaluate the influence of wind‐energy infrastructure and habitat characteristics on nest‐site selection and daily nest survival. We did not detect any influence of wind‐energy infrastructure on nest‐site selection or nest survival. Nest‐site selection and daily nest survival were influenced by vegetation structure and composition measured at 2 spatial scales. Females selected nest sites with more restored grassland containing >30% forb cover within the nesting core‐use area (i.e., 60 ha around the nest) and exhibited a functional response to the availability of that land cover type. Daily nest survival was best predicted by visual obstruction at the nest site and the amount of restored grassland containing >30% forb cover within the nesting core‐use area. We recommend wildlife managers continue to implement management practices that will provide bunchgrass‐dominated grasslands with >30% forb cover in restored grasslands (e.g., Conservation Reserve Program fields) within Columbian sharp‐tailed grouse range. © The Wildlife Society, 2019

Multiscale Habitat Selection of Lesser Prairie-Chickens in a Row-Crop and Conservation Reserve Program Land Matrix

Abstract The lesser prairie-chicken Tympanuchus pallidicinctus has received considerable attention in recent years, as a result of population decline and the uncertainty of its status under the 1973 U.S. Endangered Species Act. Substantial effort has been exerted studying the life history of the species and effects of some management practices on its ecology. However, information is lacking regarding lesser prairie-chicken use and selection of Conservation Reserve Program fields in the Southern High Plains of Texas. To fill in this knowledge gap, we assessed habitat selection by lesser prairie-chickens within Conservation Reserve Program fields, native grassland, and row-crop agriculture in Texas, 2015–2017. We assessed habitat selection using a Type II design at the second order of selection (home range placement within the landscape) and a Type III design at the third order (Global Positioning System locations within the home range). At the second order of selection, lesser prairie-chickens selected Conservation Reserve Program fields seeded in nonnative grasses (wi = 3.99, 95% CI = 1.60–6.39) and native grasses and forbs (wi = 3.25, 95% CI = 1.99–4.52) year-round. Row-crop agriculture (wi = 0.17, 95% CI = 0.06–0.28) and native grassland (wi = 0.30, 95% CI = 0.06–0.55) were avoided. Native grass Conservation Reserve Program fields were used in proportion to their availability (wi = 1.33, 95% CI = 0.81–1.85) year-round. Only Conservation Reserve Program fields seeded in native grasses and forbs were selected at the third order of selection (wi = 1.32, 95% CI = 1.16–1.47). Based on our results, Conservation Reserve Program fields provide habitat for lesser prairie-chickens, and as such, may be beneficial to persistence of the species on the High Plains of Texas.

Diversity and abundance of wild bees in an agriculturally dominated landscape of eastern Colorado

Agricultural intensification has resulted in loss of natural and semi-natural habitats impacting several important ecosystem services. One group of organisms that has suffered greatly are the bees and hence pollination, the supporting ecosystem service they complete. The United States Department of Agriculture (USDA) Conservation Reserve Program (CRP) has implemented conservation practices designed to improve habitat for pollinators in agroecosystems by paying to recover environmentally sensitive agricultural land from production, and restoring them by planting native grass mixes, pollinator-friendly legumes and wildflowers. Our study, aimed at demonstrating the efficacy of this practice, measured diversity and abundance of wild bee genera in the agricultural landscape of eastern semiarid regions of Colorado, USA, where CRP practices were implemented. Over our 3-year study, we obtained a total of 16,207 bees belonging to 51 genera. We found inconsistent differences in number of bee genera and abundance of bees in CRP fields supplemented with wildflowers compared to those with conventional grass seed mix. However, we observed only a 40–80% overlap in bee genera between fields supplemented with wildflowers and those with grass seed mixes indicating that diversity was enhanced by having both habitats. With the caveat that 3 years is a very short period to see appreciable changes, our results suggest that recovering environmentally sensitive land can strengthen pollinator populations in landscapes dominated by agricultural activities. In addition, periodic evaluation and maintenance of these recovered lands will further support the efforts towards revitalization of ecosystem services in these areas.

Density and success of upland duck nests in native‐ and tame‐seeded conservation fields

ABSTRACTThe Conservation Reserve Program (CRP) generates substantial benefits to continental duck populations by providing grassland nesting habitat in rested cropland. Seeding mixes of CRP grasslands vary among numerous conservation practices, but one contrast of interest in the Prairie Pothole Region is the use of introduced, or “tame” versus native grass. Although the benefits of CRP to duck populations are well‐known, relative values of these planting practices to nesting ducks have received little attention. Understanding differences in benefits to ducks due to planting practices would aid in prioritizing and selecting management practices for CRP and other restoration activities. We evaluated nest survival and density of ducks nesting in tame‐ and native‐seeded CRP fields in 36 study areas in the Prairie Pothole Region of North Dakota and South Dakota, USA, during 2002–2003. We searched for duck nests in 209 fields totaling 5,386 ha and found 2,941 nests. We found no support for differences in nest survival for any upland‐nesting duck species between fields seeded to tame versus native grass based on a design and analyses that accounted for spatial and temporal variation. Additionally, nest densities, adjusted for nest survival rates, of all duck species were similar between tame‐seeded and native‐seeded fields. We conclude that benefits to nesting ducks from native‐grass seeding practices of CRP were similar to those of tame‐grass seeding practices. Although there may be other reasons to plant native seed mixes when establishing CRP tracts (e.g., native pollinators or insects, other wildlife species, etc.), our study suggests that duck nesting density and nest survival are not among those reasons. Published 2018. This article is a U.S. Government work and is in the public domain in the USA.

Ecosystem carbon exchange on conversion of Conservation Reserve Program grasslands to annual and perennial cropping systems

Land use changes into and out of agricultural production may substantially influence ecosystem carbon (C) balance for many years. We examined ecosystem C balances for eight years after the conversion of 22 year-old Conservation Reserve Program (CRP) grasslands and formerly tilled agricultural fields (AGR) to annual (continuous no-till corn) and perennial (switchgrass and restored prairie) cropland. An unconverted CRP field (CRP-Ref) was maintained as a historical reference. Ecosystem C balance was assessed using adjusted net ecosystem carbon exchange (NEEadj) calculated by adding C removed in harvested biomass to NEE measured using eddy covariance method. The cumulative NEEadj of the corn and perennial systems on former CRP fields showed that these systems were a net C source to the atmosphere over the 8-year period while on former AGR fields, the perennial systems were net C sinks and the corn system near-neutral. The CRP-Ref was near neutral until a drought year when it became a net source. The corn system on the CRP field will likely reach a new lower soil C equilibrium at least 14 years after conversion but will never regain the C lost upon conversion under current no-till management with residue partially removed. On the other hand, the perennial systems could fully regain in ∼14 years the C lost following conversion. The cumulative NEEadj of the corn systems exhibited a higher C emission than did the perennial systems within the same land use histories, reflecting the dominant role of crop type and management in agricultural ecosystem C balance. Results suggest that converting croplands to grasslands results in immediate C gains whereas converting grasslands to croplands results in permanent (no-till corn with partial residue removal) or temporary (perennial herbaceous crops) net C loss to the atmosphere. This has a significant implications for global climate change mitigation where biomass production from annual and perennial crops is promoted to avoid fossil-fuel C emissions (biofuel) or to remove CO2 from the atmosphere (bioenergy C capture and storage).

Identifying the diet of a declining prairie grouse using DNA metabarcoding

ABSTRACT Diets during critical brooding and winter periods likely influence the growth of Lesser Prairie-Chicken (Tympanuchus pallidicinctus) populations. During the brooding period, rapidly growing Lesser Prairie-Chicken chicks have high calorie demands and are restricted to foods within immediate surroundings. For adults and juveniles during cold winters, meeting thermoregulatory demands with available food items of limited nutrient content may be challenging. Our objective was to determine the primary animal and plant components of Lesser Prairie-Chicken diets among native prairie, cropland, and Conservation Reserve Program (CRP) fields in Kansas and Colorado, USA, during brooding and winter using a DNA metabarcoding approach. Lesser Prairie-Chicken fecal samples (n = 314) were collected during summer 2014 and winter 2014–2015, DNA was extracted, amplified, and sequenced. A region of the cytochrome oxidase I (COI) gene was sequenced to determine the arthropod component of the diet, and a portion of the...

Soil microbial community restoration in Conservation Reserve Program semi-arid grasslands

The Conservation Reserve Program (CRP) in the Southern High Plains (SHP) is known to play a crucial role in maintaining ecosystem health by reducing soil erosion. However, the restoration of soil biological health (biological community and its function) over time under CRP have not been clearly elucidated. The objective of this study was to describe the changes in the soil microbial community composition using a CRP chronosequence. Soil samples (0-10 cm and 10-30 cm) were collected in 2012 and 2014 from 26 fields across seven counties within the SHP and included seven croplands (representing 0 y in CRP), 16 CRP fields of varying ages (8-28 y as of 2014), plus three rangelands (representing no disturbance for > 30 y). Multiple regression analysis was conducted to evaluate the impacts of CRP restoration on soil microbial biomass. Shifts in soil microbial community composition, according to fatty acid methyl ester (FAME) profiles, with increasing CRP restoration years were explored using multivariate ordination. Total microbial biomass (using total FAME content as a proxy) increased with CRP years at 10-30 cm in 2012 and both depths in 2014. Although different environmental conditions were present during the two sampling years (2012 followed a record extreme drought in 2011 with conditions improving in 2014), the physiological stress of microbial community indicated by ratios of saturated to monounsaturated FAME biomarkers consistently decreased with CRP restoration years in both sampling years and both depths. A shift in microbial community composition was measured during CRP restoration at 0-10 cm in both sampling years (and at 10–30 cm in 2012) with an increase in relative fungal abundance through the initial 15 y of CRP and then a decline after 15 y. The overall increase in soil microbial biomass and decrease in microbial physiological stress indicators with increasing years under CRP illustrates how this is a valuable restoration program for building soil health in fragile, sandy SHP soils. The mechanisms underlying the decline in fungal abundance in years 15–28 are unclear and the associated reduction in the fungal to bacterial ratio does not necessarily reflect reduced soil health. Overall, the CRP program is an effective restoration practice in the SHP that can restore overall soil biological attributes including microbial biomass, re-establish the soil microbial community with decreased microbial physiological stress, and improve soil microbial functions related to C sequestration.

Soil carbon sequestration potential in semi-arid grasslands in the Conservation Reserve Program

The Conservation Reserve Program (CRP) in the USA plays a major role in carbon (C) sequestration to help mitigate rising CO2 levels and climate change. The Southern High Plains (SHP) region contains >900.000ha enrolled in CRP, but a regionally specific C sequestration rate has not been studied, and identification of the C pools and processes important in controlling C sequestration rates remain unresolved. We aimed to address these gaps by utilizing a CRP chronosequence with historical rangeland as a reference ecosystem. Soil samples (0–10 and 10–30cm) were collected in 2012 and 2014 from a total of 26 fields across seven counties within the SHP and included seven croplands (0 y in CRP), 16 CRP fields that ranged from 6 to 26y (as of 2012), plus three rangelands. Multiple regression analysis was conducted to gauge the rate of C sequestration under CRP within C pools: soil organic C (SOC), particulate organic matter C (POM-C), and microbial biomass C (MBC), with two additional predictors (soil clay+silt content and precipitation). Despite attempts to control for soil texture by targeting a dominant soil series (Amarillo fine sandy loam), the percent of clay+silt (15.2–48.7%) significantly influenced C accrual. The C sources (C3 from previous cropping systems or C4 from CRP grasses) in SOC and POM-C were assessed using stable C isotope signatures. Additionally, the role of soil microbes in C sequestration was evaluated by investigating the relationship between MBC and CO2 flux and C sequestration. SOC increased at a rate of 69.82 and 132.87kgCha−1y−1 and would take approximately 74 and 77 y to reach the rangeland C stocks at 0–10 and 0–30cm, respectively. The C4‐C primarily from the introduced grasses was the main source of C sequestration. SOC gains were essentially due to increases in POM-C and MBC, accounting for 50.04 and 15.64% of SOC sequestration at 0–30cm, respectively. The highest semi-partial correlation coefficients between the increasing years under CRP restoration and MBC indicated CRP had the strongest effect on MBC compared to other C pools. In addition, increasing soil CO2 flux and MBC:SOC ratio with years of CRP restoration indicated MBC played a critical role in the C sequestration process. Conservation of CRP lands and efforts to sustain perennial systems in this highly erodible landscape should be a high priority of conservation programs. In doing so, significant offsets to increasing atmospheric CO2 levels may be achieved in addition to erosion control and improved wildlife habitat.

Relative Invertebrate Abundance and Biomass in Conservation Reserve Program Plantings in Northern Missouri

We measured relative invertebrate abundance, biomass, and diversity in Conservation Reserve Program (CRP) fields planted to red clover (Trifolium pratense)/timothy (Phleum pratense), timothy, orchard-grass (Dactylis glomerata), tall fescue (Festuca pratensis), warm-season grasses (big bluestem [Andropogon gerardi]/switch grass [Panicum virgatum]), orchard-grass/Korean lespedeza (Kummerowia stipu/,acea), and conventionally-tilled soybeans, to assess brood habitat quality for northern bobwhite (Colinus virginkinus). We sampled invertebrate populations by vacuuming along 3 15-m transects (4.56 m2/sample) within 4 fields of each planting type, at 2-week intervals from 1 July to 15 August 1990 and 1991. Invertebrate abundance and biomass were lowest in early August (P < 0.05). The CRP fields planted to a red clover/timothy mixture, and dominated by red clover, had the highest levels of invertebrate abundance and biomass (P < 0.05). Conventionally-tilled soybeans had lower invertebrate abundance and biomass than all CRP covertypes (P< 0.05). Mean invertebrate abundance and biomass in CRP fields were 4 times that of soybean fields. In northern Missouri, CRP fields could provide quality brood habitat if structural characteristics are also consistent with brood foraging needs. Incorporation of a legume in CRP plantings may produce higher invertebrate densities and improve the value of these fields as brood habitat.

Patch Size and Nest Density Influence Nest Survival

Nest predation is the primary cause of avian nest failure and therefore an important driver of avian population growth. Studies indicate that landscape context plays an important role in nest success, and although this is widely attributed to changes in nest predator communities, landscape context also influences nest density which affects predator search area and effort. Much debate remains as to whether specifically the size of a habitat patch or the density of nests has the greatest effect on nest predation rates. We explored the interactions between landscape context, predator efficiency, and nest survival. Northern bobwhite quail (Colinus virginianus) possess specific habitat requirements within a small home range and are a short-lived species that relies upon high reproductive performance, which make them the ideal system to test the extent to which landscape context affects nest predation rates. We investigated the extent to which the size of a grassland patch versus nest density affects nest survival by studying the predation rates of 617 artificial nests during two 23 day trials on 12 study sites in south central Nebraska. To examine the effects of patch size, we selected 6 study sites that were small patches of grassland (including pastures and Conservation Reserve Program fields) ranging in size from 40-60 ha and 6 study sites that were approximately 50 ha sections of larger contiguous grasslands. A high density of artificial nests were placed on half of the small and large patch study sites with the remaining sites having a low density of nests, for the second trial the nest density treatments were switched for each site.

Grassland Bird Productivity in Warm Season Grass Fields in Southwest Wisconsin

Abstract Surrogate grasslands established through federal set-aside programs, such as U.S. Department of Agriculture's Conservation Reserve Program (CRP), provide important habitat for grassland birds. Warm season grass CRP fields as a group have the potential for providing a continuum of habitat structure for breeding birds, depending on how the fields are managed and their floristic composition. We studied the nesting activity of four obligate grassland bird species, Bobolink (Dolichonyx oryzivorus), Eastern Meadowlark (Sturnella magna), Grasshopper Sparrow (Ammodramus savannarum), and Henslow's Sparrow (A. henslowii), in relation to vegetative composition and fire management in warm season CRP fields in southwest Wisconsin during 2009–2011. Intraspecific variation in apparent nest density was related to the number of years since the field was burned. Apparent Grasshopper Sparrow nest density was highest in the breeding season immediately following spring burns, apparent Henslow's Sparrow nest density w...

Contribution of CRP to Illinois Bobwhite Habitat at the Landscape Level (Poster Abstract)

Northern bobwhite (Colinus virginianus) population declines in the midwest have been attributed to habitat degradation and loss due mainly to intensified agricultural land use and farming practices. Thus, there was initial optimism that the Conservation Reserve Program (CRP) would benefit bobwhites by converting cropland to semi-permanent grassland. However, CRP apparently has not positively impacted regional or statewide population trends in Illinois. Deficiencies at both site and landscape level may be involved. To address the latter issue, we mapped the location of each individual CRP field (> 8,800) in 11 representative counties within the bobwhite range in Illinois. We then analyzed their spatial relationship to other land cover and bobwhite habitat using Geographic Information Systems and a statewide digital land cover map based on classified satellite imagery. Existing bobwhite habitat and CRP fields tended to be spatially correlated because both are largely confined to moderately rolling terrain as opposed to very hilly or very flat areas. Nevertheless, almost 25% of all existing CRP acreage within our 11 study counties occurred in landscapes with insufficient woody edge to support high bobwhite populations. Furthermore, CRP did not always provide the habitat component most limiting for bobwhites.

Nest-Site Characteristics of Northern Bobwhites Translocated Into Weeping Lovegrass CRP

Habitat loss and fragmentation have been considered major causes for the decline of northern bobwhite (Colinus virginianus). There are . 400,000 ha of weeping lovegrass (Eragrostis curvula) Conservation Reserve Program (CRP) fields in the Southern High Plains of Texas some of which could be modified to provide usable habitat for northern bobwhites. Timely colonization of improved CRP habitat by northern bobwhite is unlikely without transplantation, because of distance from existing populations. We radio-marked and transplanted 94 northern bobwhite into weeping lovegrass CRP and monitored nest success. We recorded high nest success in 2002 (70%) and 2003 (71%) for northern bobwhite nesting in weeping lovegrass CRP in the area studied. The composition of weeping lovegrass CRP fields available in our study area appears to be suitable nesting cover for northern bobwhite.

Effects of Northern Bobwhite Habitat Management Practices on Red Imported Fire Ants

Management practices that create early successional plant communities through disturbance (discing and prescribed fire) often are prescribed for restoration of declining northern bobwhite (Colinus virginianus) populations. Because disturbance may facilitate invasion of exotic flora and fauna such as red imported fire ants (RIFA, Solenopsis invicta), we hypothesized that habitat management practices commonly used to enhance bobwhite habitat might have the unintended consequence of increasing local abundance of RIFA. During 1999, we tested effects of 4 treatments (spring discing, spring prescribed burning, spring mowing, and no management), in a randomized complete block design (n = 10) on RIFA abundance in Conservation Reserve Program (CRP) fields in central Mississippi. We surveyed RIFA abundance using 3 measures: 1) mound density, 2) a population index based on worker ant and brood estimates, and 3) foraging activity as indexed by attraction to protein bait cups. During May 1999, mound density (P = 0.0136) and population index (P 0.0078) differed among treatments, with abundance values greatest in plots treated with fire, and lowest in disced plots. The index of foraging activity did not differ among treatments (P = 0.6637). During October 1999, mound density (P = 0.0334) and population index (P = 0.0451) differed among treatments with abundance values greatest in plots receiving fire and disc treatments, and lowest abundance in control plots. The index of foraging activity did not differ among treatments (P = 0.9079). Disturbance tools such as prescribed fire and discing are essential to maintain plant communities to which bobwhite are adapted; however, they may have the unintended consequence of facilitating invasion of RIFA and increasing local RIFA populations.

Arthropod Consumption by Northern Bobwhite Chicks in Managed Tall Fescue Monocultures

An extensive amount of Conservation Reserve Program (CRP) habitat for northern bobwhite (Colinus virginianus) has been lost to planting of tall fescue (Schedonorus phoenix). We conducted foraging trials using human-imprinted bobwhite chicks (n 1⁄4 288) and collected terrestrial arthropods using a customized yard vacuum to assess the effects of 3 USDA mid-contract management (MCM) cost-share practices on chick foraging rates and arthropod prey selection in 36 tall fescue-dominated CRP fields in Illinois during 2008. We applied fall strip disking, fall glyphosate spraying, and fall glyphosate spraying followed by spring legume interseeding in alternating strips to 33% of each treatment field on a 3-year rotation. Glyphosate and glyphosate-interseeding treatments provided greater brood habitat benefits for bobwhite chicks than disking and control fields. Chicks consumed a greater abundance (P , 0.0001) and biomass (P 1⁄4 0.0017) of arthropods in managed fields than in unmanaged fields. Abundance and biomass of arthropods consumed by chicks were higher in glyphosate and glyphosate-interseeded strips with 1-, 2-, and 3-growing seasons post-treatment, but disking only provided this benefit for 1 growing season. Vacuum sampling provided a poor index of the availability of arthropods to bobwhite chicks, as measured by foraging of imprinted chicks. Vacuum sampling indicated arthropod abundance was greater in unmanaged than in managed fields (P 1⁄4 0.170). Custom vacuums are not an appropriate tool for measuring the abundance of arthropods important to bobwhite chicks in tall fescue CRP. Fall strip disking is an inferior MCM practice to glyphosate-based treatments in tall fescue- dominated CRP.