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Red Oak Acorn Production, Mass, and Gross Energy Dynamics in the Mississippi Alluvial ValleyLeach, Alan Gregory 30 April 2011 (has links)
Acorns of red oaks (Quercus spp; Subgenus Erythrobalanus) are important forage for wildlife and seed for oak regeneration. I estimated production of viable acorns by red oaks in 5 forests in the Mississippi Alluvial Valley (MAV) and 2 greentree reservoirs (GTRs) in Mississippi. Mean acorn production in the MAV was 439 kg(dry)/ha of red oak crown (CV = 29%) during autumn-winter 2009-2010 and 794 kg/ha (CV = 19%) in GTRs during autumn-winters 2008-2010. I recommend researchers sample acorn production in the MAV for ≥5 years to improve precision of estimates (i.e., CV ≤ 15%). I estimated mass and gross energy (GE) of viable red oak acorns after 90 days in unflooded and flooded hardwood bottomlands in Mississippi. Within species, mass loss of acorns was <8.4% and variation in GE ≤0.08 kcal(dry)/g. Winter decomposition of intact viable red oak acorns would have minimal effect on wildlife carrying capacity of hardwood bottomlands.
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Factors influencing avian community structure in bottomland hardwood forests of the southeastern United StatesHusak, Michael Scott 05 May 2007 (has links)
Bottomland hardwood forests (BHF) are a disappearing habitat of importance to numerous migratory and non-migratory birds of conservation concern. Thus, understanding variables of bottomland hardwood forests that affect avian assemblage patterns are of great interest. I examined factors influencing avian assemblage and guild patterns in BHF of Noxubee National Wildlife Refuge in east-central Mississippi by conducting winter and spring fixed-radius avian point counts and vegetation surveys from 2002 ? 2004. The goals of this project were to 1) determine effects of greentree reservoir (GTR) management on breeding and wintering non-game bird community structure, 2) test hypotheses regarding plant structural complexity and avian assemblage patterns, and 3) examine the effects of landscapes on local bird assemblages within BHF. Greentree reservoirs have subtle effects on avian communities. Sites within GTRs, sites in BHF adjacent to GTRs, and random, unimpounded BHF sites differed significantly in breeding bird diversity, richness, and evenness. However, the patterns exhibited were a decreasing continuum of these variables with sites peripheral to GTRs demonstrating intermediate values. No differences were found among abundance, conservation status, or habitat specialization of breeding birds. Guild parameters did not differ except for a decreasing continuum in species richness among unimpounded BHF, BHF to GTRs, and GTR sites. The canopy nesting and ground gleaning foraging guilds were the only guilds found to differ among sites. Patterns could indicate that given the inherent structural variation of BHF, GTRs are within the expected range of variation, or GTR management could be indirectly affecting the surrounding landscape. GTR management did not affect community parameters for wintering birds, and only the bark gleaning foraging guild varied among sites (higher in GTRs). These results reflect the ubiquitous nature of wintering birds in east-central Mississippi forests. There was direct support for the structural vertical heterogeneity hypothesis; however, regression analyses of principal component scores derived from sixty structural descriptor metrics suggest that avian communities and guilds are more directly influenced by overall local plant structural complexity, as predicted by the spatial heterogeneity hypothesis. Avian community and guild parameters did not differ among the three landscape contexts defined by 1,000 and 1,500m buffers.
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