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Jackson, MO, United States

Henderson D.E.,Open Rivers and Wetlands Field Station | Jose S.,University of Missouri
Agroforestry Systems | Year: 2010

A study was conducted in an agricultural field to examine the biomass production of three fastgrowing short rotation woody crop (SRWC) species, Populus deltoides, Quercus pagoda, and Platanus occidentalis using fertilization and irrigation (fertigation). The study included a randomized complete block (RCB) with five treatments; control, irrigated, and irrigated with 56, 112, and 224 kg nitrogen (N) ha-1 year-1. We quantified survival, basal area, standing biomass, aboveground net primary productivity (ANPP), leaf area index (LAI), and growth efficiency (GE) for each species along the soil nitrogen and water gradient. P. deltoides had low rates of survival (83, 82, and 77% years six, seven, and eight, respectively), but had production values greater than Q. pagoda and P. occidentalis. Standing biomass reached its peak for P. deltoides and P. occidentalis (17.56 and 10.36 Mg ha1, respectively) in the irrigation treatment, and in the 112 kg N treatment for Q. pagoda (5.42 Mg ha-1). P. deltoides and P. occidentalis ANPP peaked in the irrigation treatment (6.66 and 6.31 Mg ha-1 year-1, respectively) and in the 112 kg N (4.43 Mg ha-1 year-1) for Q. pagoda. ANPP was correlated with LAI; however, the relationship was species specific. Maximum ANPP was reached below the maximum LAI for Q. pagoda and P. occidentalis. P. deltoides ANPP was highest at the maximum LAI, which was achieved with IRR. These results suggest that species-specific cultural practices producing optimum LAI and maximum ANPP should be identified before fertigation techniques are adopted widely for SRWC production on agricultural fields. © 2010 Springer Science+Business Media B.V. Source

Motsinger J.R.,University of Missouri | Kabrick J.M.,U.S. Department of Agriculture | Dey D.C.,U.S. Department of Agriculture | Henderson D.E.,Open Rivers and Wetlands Field Station | Zenner E.K.,Pennsylvania State University
New Forests | Year: 2010

Regenerating oaks (Quercus L.) on mesic and hydric sites has remained a problem largely because of inadequate density and poor distribution of large oak advance reproduction prior to harvesting. We examined the effect of midstory and understory removal on the establishment and 3-year development of natural and artificial sources of pin oak (Q. palustris Muenchh.) advance reproduction in bottomland forests in southeastern Missouri, USA. Midstory and understory removals increased the photosynthetically-active radiation (PAR) reaching the seedling layer from about 3 to 15%. This increased light did not increase the density of natural pin oak advance reproduction compared to control, but it increased the survival and nominally increased the growth of the natural pin oak advance reproduction. Where the midstory and understory had been removed, underplanted RPM® container stock and bareroot pin oak stock maintained high survival, but of the two only the RPM® stock maintained positive height and diameter growth while bareroot stock suffered some growth reductions. Pin oaks originating from the direct seeding of stratified acorns sown in the spring had low germination and survival, but the survivors had growth rates similar to those of natural seedlings in thinned stands. Applying triclopyr to competitors in the ground flora layer only nominally increased PAR but reduced the percent survival and marginally increased the growth of natural and artificial pin oak. We conclude that artificial reproduction may be used to further increase the probability of achieving adequate numbers of the desired species in the future. Bareroot seedlings may not perform as well as RPM® seedlings and natural seedlings already present. However, bareroot and RPM® seedlings remained significantly larger than the natural seedlings after 3 years. © 2009 U.S. Government. Source

McCain K.N.S.,Open Rivers and Wetlands Field Station | McCain K.N.S.,Southern Illinois University Carbondale | Baer S.G.,Southern Illinois University Carbondale | Blair J.M.,Kansas State University | Wilson G.W.T.,Oklahoma State University
Restoration Ecology | Year: 2010

Warm-season (C 4) grasses commonly dominate tallgrass prairie restorations, often at the expense of subordinate grasses and forbs that contribute most to diversity in this ecosystem. To assess whether the cover and abundance of dominant grass species constrain plant diversity, we removed 0, 50, or 100% of tillers of two dominant species (Andropogon gerardii or Panicum virgatum) in a 7-year-old prairie restoration. Removing 100% of the most abundant species, A. gerardii, significantly increased light availability, forb productivity, forb cover, species richness, species evenness, and species diversity. Removal of a less abundant but very common species, P. virgatum, did not significantly affect resource availability or the local plant community. We observed no effect of removal treatments on critical belowground resources, including inorganic soil N or soil moisture. Species richness was inversely correlated with total grass productivity and percent grass cover and positively correlated with light availability at the soil surface. These relationships suggest that differential species richness among removal treatments resulted from treatment induced differences in aboveground resources rather than the belowground resources. Selective removal of the dominant species A. gerardii provided an opportunity for seeded forb species to become established leading to an increase in species richness and diversity. Therefore, management practices that target reductions in cover or biomass of the dominant species may enhance diversity in established and grass-dominated mesic grassland restorations. © 2010 Society for Ecological Restoration International. Source

Koch B.,U.S. Environmental Protection Agency | Brooks R.C.,Southern Illinois University Carbondale | Oliver A.,U.S. Army | Herzog D.,Open Rivers and Wetlands Field Station | And 5 more authors.
Transactions of the American Fisheries Society | Year: 2012

The pallid sturgeon Scaphirhynchus albus is a U.S. federally endangered species that occurs in the 320-km middle Mississippi River (MMR). Historic in-channel island habitat has vanished, and the extent of the population's range within the MMR is unknown.We surgically implanted ultrasonic transmitters in 88 adult pallid sturgeon (>600 mm fork length;mean=791 mm) during 2002-2005 and used boat-mounted hydrophones to quantify their seasonal use of major MMR habitat features (wing dikes, side channels, island side channel tips, tributaries, and main channel; total of 8,629 river kilometers monitored). Distance fromhabitat features (gravel bars, wing dikes, and island side channels) was quantified during spring, a period considered to be critical for many fish species.We quantified maximum seasonal movement of each fish in the entire MMR with stationary data-logging hydrophones during 2004-2006. Combining data across years and seasons, we found that pallid sturgeon selected the tips of wing dikes over other habitat features. However, during spring pallid sturgeon moved from the tips of wing dikes to within about 100 m of known gravel bars. Maximum distance moved by pallid sturgeon varied the most in spring relative to other seasons. One pallid sturgeon moved through the entire study reach, and a few individuals left the MMR for the Missouri River or the lower Mississippi River. Unique flow and substrate characteristics of wing dikes probably emulated missing habitat complexity (i.e., in-channel islands, deep scour holes, and sand bars). Other habitats such as gravel bars may be important during spring, although their contributions to reproduction, foraging, and survival of pallid sturgeon are unknown. The range of this pallid sturgeon population extends beyond the entire stretch of the MMR into other river basins; thus, the population requires rangewide management. © American Fisheries Society 2012. Source

Bueltmann A.T.,Open Rivers and Wetlands Field Station | Bueltmann A.T.,Southeast Missouri State University | Phelps Q.E.,Open Rivers and Wetlands Field Station | Phelps Q.E.,Southeast Missouri State University
Copeia | Year: 2015

Harvest regulations are important for fishes that are both commercially and recreationally sought after such as Channel catfish (Ictalurus punctatus) throughout the Middle Mississippi River. Monitoring total harvest and understanding Channel catfish population dynamics (i.e., recruitment, growth, and mortality) are crucial for managing a sustainable population. Total commercial harvest and current harvest regulations in the Middle Mississippi River have not recently been evaluated. Thus, we evaluated total commercial harvest reports from 1945-2012 along with commercial fishing effort, population dynamics for the Middle Mississippi River Channel catfish population, and simulated the effects of various length limits on the reproductive potential and yield per recruit of the Channel catfish population. Overall, total commercial harvest has drastically declined from 1990-2012, while commercial effort has remained relatively constant. We speculate overexploitation as a possible cause to the decline in harvest given relatively constant commercial fishing effort. We collected 501 Channel catfish from the Middle Mississippi River during spring, summer, and fall of 2012-2013. Channel catfish were weighed, measured, aged (via lapilli otoliths), and egg samples were collected for fecundity estimates to obtain population level information. We used the static form of the spawning potential ratio (SPR) and the yield per recruit model to simulate variable exploitation rates at three different length limits (e.g., 356 mm, 381 mm, and 406 mm). Our yield per recruit simulation modeling results identified that a 381 mm length limit would not lead to growth overfishing until exploitation rates were between ∼50 and 70%. Furthermore, simulation modeling predicted that the SPR was not below a critical minimum conservative threshold of 20% until exploitation rates reached between 50 and 70%; therefore, the population appears to be sustainable under the current length limit of 381 mm, if exploitation rates do not exceed 50-70%. © 2015 by the American Society of Ichthyologists and Herpetologists. Source

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