Negus L.P.,Oklahoma State University |
Davis C.A.,Oklahoma State University |
Wessel S.E.,Nebraska Game and Parks Commission
American Midland Naturalist | Year: 2010
Throughout the Midwestern U.S., grassland birds have been declining faster than any other group of birds, with the main cause for these declines being the extensive loss of native prairies. During the last 25 y, surrogate grasslands, such as Conservation Reserve Program (CRP) lands, have become increasingly important as an alternative habitat for grassland birds. However, many CRP grasslands that once provided excellent habitat are now dominated by monculture stands of grass, resulting in a less diverse habitat that has reduced wildlife benefits. In summer 2002, the Nebraska Game and Parks Commission and Pheasants Forever partnered with the United States Department of Agriculture's Farm Service Agency and Natural Resource Conservation Service to initiate a program that promotes disking and interseeding legumes as a mid-contract management practice in CRP fields. The objectives of this study were to determine grassland bird abundance and nest-productivity in disked and interseeded CRP fields and evaluate vegetative responses to disking and interseeding. We conducted our study on 16 CRP fields in Stanton County, Nebraska where we used fixed transects to determine avian species richness and abundance and nest-searched twelve 4-ha plots to determine nest productivity in treatment (managed by disking and interseeding) and reference (unmanaged) CRP fields. We also recorded vegetation characteristics along each transect and at each nest. Overall abundance in treatment fields was 4.49 ± 0.25 (se) birds/transect compared to 2.93 ± 0.21 birds/transect in reference fields. Species richness and diversity were also higher in treatment fields. There was no difference in nest density or nest success between treatment and reference fields. Treatment field vegetation had higher percentages of forbs and bare ground than reference sites. Maximum vegetation height and horizontal visual obstruction were also higher in treatment sites. To accommodate the most grassland bird species in CRP fields, management of CRP fields should include establishing an annual rotation of disking/interseeding, while leaving portions of fields in mature grass stands. Future research should focus on methods that will increase the longevity of the vegetation effects of disking/interseeding legumes. © 2010, American Midland Naturalist.
Steffensen K.D.,Nebraska Game and Parks Commission |
Powell L.A.,University of Nebraska - Lincoln
North American Journal of Fisheries Management | Year: 2010
The population of pallid sturgeon Scaphirhynchus albus in the lower Missouri River between Gavins Point Dam (river kilometer [rkm] 1,305.2) and the confluence with the Mississippi River (rkm 0.0) remains imperiled, little to no natural recruitment occurring. Artificial propagation and subsequent population augmentation (i.e., stocking) may be the only viable option for maintaining pallid sturgeon populations in the lower Missouri River in the near term. Because relatively little is known about the ability of hatchery-reared pallid sturgeon to survive, the objective of this study was to quantify survival estimates for hatchery-reared pallid sturgeon stocked into the lower Missouri River. We used stock-recapture data collected from 1994 to 2008 to derive survival estimates based on the Cormack-Jolly-Seber model within program MARK. Since 1994, a total of 78,244 hatchery-reared pallid sturgeon have been released and 1% of these have been recaptured. Recapture numbers by size at stocking were as follows: 48 age 0, 730 age 1, and 38 older than age 1. Stocked age-0 hatchery-reared pallid sturgeon had an estimated apparent survival rate of 0.051 (SE = 0.008), compared with 0.686 (SE=0.117) for age-1 fish and 0.922 (SE=0.015) for fish older than age 1. Our analysis confirms that hatchery-reared pallid sturgeon can survive in the wild and contribute to the overall population of this species. These estimates should provide critical information for decisions regarding stocking strategies within the lower Missouri River and enable biologists to estimate the number of stocked pallid sturgeon that reach sexual maturity. © American Fisheries Society 2010.
Huenemann T.W.,Nebraska Game and Parks Commission |
Dibble E.D.,Fisheries and Aquaculture |
Fleming J.P.,Fisheries and Aquaculture
Transactions of the American Fisheries Society | Year: 2012
Water turbidity has the capacity to influence fish foraging success and behavior. The largemouth bass Micropterus salmoides is a popular sport fish in the southeastern United States that is primarily a visual predator. The high turbidity in many systems can be attributed to sediment loading from agricultural lands, and it can reduce the availability of light in the water column and have direct impacts on largemouth bass foraging success. We investigated the effect of different turbidity levels (0, 10, 25, 50, 100, and 250 nephelometric turbidity units [NTU]) on largemouth bass foraging in aquaria by testing the hypothesis that turbidity has no effect on the time required to locate tethered prey (fatheadminnow Pimephales promelas and golden shiner Notemigonus crysoleucas) or ultimate capture success. The percentages of prey captured that were derived from aggregated data in multiple trials at the different treatment levels differed significantly. One-hundred percent of the largemouth bass in the 0-NTU treatments captured the prey. Conversely, only 15% of the largemouth bass in the 250-NTU treatments captured the prey throughout all trials. The average time taken to capture the prey also was significantly different between treatment combinations, with time to interaction increasing as turbidity increased. The results from this study suggest that greater turbidity levels reduce the ability of largemouth bass to capture prey and increase the time taken to locate and interact with prey. Thus, turbidity may impact individual fitness and management strategies. © American Fisheries Society 2012.
Dinges A.J.,University of Missouri |
Webb E.B.,University of Missouri |
Vrtiska M.P.,Nebraska Game and Parks Commission
Wildlife Biology | Year: 2015
The Light Goose Conservation Order (LGCO) was initiated in 1999 to reduce mid-continent populations of light geese (lesser snow geese Chen caerulescens and Ross's geese C. rossi). However, concern about potential for LGCO activities (i.e. hunting activities) to negatively impact non-target waterfowl species during spring migration in the Rainwater Basin (RWB) of Nebraska prompted agency personnel to limit the number of hunt days each week and close multiple public wetlands to LGCO activities entirely. To evaluate the effects of the LGCO in the RWB, we quantified waterfowl density at wetlands open and closed to LGCO hunting and recorded all hunter encounters during springs 2011 and 2012. We encountered a total of 70 hunting parties on 22 study wetlands, with over 90% of these encounters occurring during early season when the majority of waterfowl used the RWB region. We detected greater overall densities of dabbling ducks Anas spp., as well as for mallards A. platyrhynchos and northern pintails A. acuta on wetlands closed to the LGCO. We detected no effects of hunt day in the analyses of dabbling duck densities. We detected no differences in mean weekly dabbling duck densities among wetlands open to hunting, regardless of weekly or cumulative hunting encounter frequency throughout early season. Additionally, hunting category was not a predictor for the presence of greater white-fronted geese Anser albifrons in a logistic regression model. Given that dabbling duck densities were greater on wetlands closed to hunting, providing wetlands free from hunting disturbance as refugia during the LGCO remains an important management strategy at migration stopover sites. However, given that we did not detect an effect of hunt day or hunting frequency on dabbling duck density, our results suggest increased hunting frequency at sites already open to hunting would likely have minimal impacts on the distribution of non-target waterfowl species using the region for spring staging. © 2015 The Authors.
Steffensen K.D.,Nebraska Game and Parks Commission |
Powell L.A.,University of Nebraska - Lincoln |
Pegg M.A.,University of Nebraska - Lincoln
North American Journal of Fisheries Management | Year: 2012
The population size of pallid sturgeon Scaphirhynchus albus is currently unknown throughout much of the Missouri River. Listed as federally endangered in 1990, the pallid sturgeon remains one of the rarest fishes in the Missouri and Mississippi River basins, and little to no natural recruitment occurs. Artificial population supplementation via a hatchery propagation program was initiated, necessitating the collection of sexually mature pallid sturgeon. Therefore, the Nebraska Game and Parks Commission maintained an intensive broodstock collection and mark– recapture effort from 2008 to 2010 to capture reproductively ready adults for the propagation program. Coordinated crews fished baited trotlines from the confluence of the Platte and Missouri rivers at river kilometer (rkm) 957.6 to a point about 80.5 rkm downstream. A total of 438 pallid sturgeon were captured, which amounts to a 7.8% recapture rate. The objectives of the study were to (1) use these data to estimate the annual population sizes of wild-origin and hatchery-reared pallid sturgeon within the above-mentioned 80.5-rkm reach of the lower Missouri River and (2) compare current population levels with the Pallid Sturgeon Recovery Team’s population objective. We used the mark–recapture data in a robust-design analysis to derive population estimates and annual survival, capture, and temporary emigration rates. The annual population estimate for wild pallid sturgeon varied from 5.4 to 8.9 fish/rkm, whereas the estimate for known hatchery-reared fish varied from 28.6 to 32.3 fish/rkm. The robust-design approach to our analysis resulted in useful estimates of population size and other variables important to quantifying species recovery and management targets; the approach may be suitable for other fisheries management data sets. © American Fisheries Society 2012.