Moist‐Soil Seed Abundance in Managed Wetlands in the Mississippi Alluvial Valley

Abstract

Managed moist‐soil units support early succession herbaceous vegetation that produces seeds, tubers, and other plant parts used by waterfowl in the Mississippi Alluvial Valley (MAV), USA. We conducted a stratified multi‐stage sample survey on state and federal lands in the MAV of Arkansas, Louisiana, Mississippi, and Missouri during autumns 2002–2004 to generate a contemporary estimate of combined dry mass of seeds and tubers (herein seed abundance) in managed moist‐soil units for use by the Lower Mississippi Valley Joint Venture (LMVJV) of the North American Waterfowl Management Plan. We also examined variation in mean seed abundance among moist‐soil units in 2003 and 2004 in relation to management intensity (active or passive), soil pH and nutrient levels, proportional occurrence of plant life‐forms (e.g., grass, flatsedge, and forb; vine; woody plants), and unit area. Estimates of mean seed abundance were similar in 2002 (x̄ = 537.1 kg/ha, SE = 100.1) and 2004 (x̄ = 555.2 kg/ha, SE = 105.2) but 35–40% less in 2003 (x̄ = 396.8 kg/ha, SE = 116.1). Averaged over years, seed abundance was 496.3 kg/ha (SE = 62.0; CV = 12.5%). Multiple regression analysis indicated seed abundance varied among moist‐soil units inversely with proportional occurrence of woody vegetation and unit area and was greater in actively than passively managed units (R2adj = 0.37). Species of early succession grasses occurred more frequently in actively than passively managed units (P ≤ 0.09), whereas mid‐ and late‐succession plants occurred more often in passively managed units (P ≤ 0.02). We recommend the LMVJV consider 556 kg/ha as a measure of seed abundance for use in estimating carrying capacity in managed moist‐soil units on public lands in the MAV. We recommend active management of moist‐soil units to achieve maximum potential seed production and further research to determine recovery rates of seeds of various sizes from core samples and the relationship between seed abundance and unit area. (JOURNAL OF WILDLIFE MANAGEMENT 72(3):707–714; 2008)

Distribution and Habitat Associations of Breeding Secretive Marsh Birds in Louisiana’s Mississippi Alluvial Valley

“…This may be indicative of the fact that regional wetland management is often focused on providing food and habitat for migrating and wintering waterfowl (Strader and Stinson 2005), a process that encourages frequently resetting succession and eliminating robust emergent plants (Kross et al 2007). Management for breeding SMBs may be incorporated into an overall wetland management strategy by allowing ditches, deeper water bodies, moist soil units, or parts of units already dominated by robust emergent plants to remain flooded during the spring and summer.…”

Comprehensive Framework for Ecological Assessment of the Migratory Bird Habitat Initiative Following the Deepwater Horizon Oil Spill

“…We also conducted surveys to estimate waterbird abundance and species richness, and characterize avian-community structure on MBHI and other ricelands in the GC JV region during autumn through spring. Although studies similar to ours have been conducted in the MAV (Kross et al 2008;Manley et al 2004;Stafford et al 2006Stafford et al , 2010, an analogous study has not been conducted in the GC JV region, where Rice agri-systems and production strategies differ markedly from practices in the MAV (Marty 2013).…”

“…We estimated relative abundances of detected waterbirds using conventional flush surveys from late summer 2011 through April 2012 (Fleming 2010, Weegman 2013. We also collected soil cores from wetlands in October 2011 and March 2012 to estimate moist-soil seed abundance for migrating and wintering waterbirds, in part so that LCC partners could then use these data to calculate duck and other waterbird energy-days (Kross et al 2008, Reinecke et al 1989.…”

Effects of Hydrogen Peroxide as a Core Sample Processing Solvent on Invertebrate Biomass

“…Scientists often use solvents to dissolve substrates and increase efficiency of sample processing (Kross et al 2008;Hagy et al 2011;Straub et al 2012). A common method used to increase efficiency of processing core samples from clay-laden soils is treatment with 3% hydrogen peroxide (H 2 O 2 ; Kross et al 2008;Havens et al 2009;Hagy and Kaminski 2012;Olmstead et al 2013). Hydrogen peroxide disassociates soil particles and facilitates separation of seeds, tubers, and invertebrates from the soil (Bohm 1979).…”