Giselle Rodriguez

Arbuscular mycorrhizal fungal community differs between a coexisting native shrub and introduced annual grass

Arbuscular mycorrhizal fungi (AMF) have been implicated in non-native plant invasion success and persistence. However, few studies have identified the AMF species associating directly with plant invaders, or how these associations differ from those of native plant species. Identifying changes to the AMF community due to plant invasion could yield key plant–AMF interactions necessary for the restoration of native plant communities. This research compared AMF associating with coexisting Bromus tectorum, an invasive annual grass, and Artemisia tridentata, the dominant native shrub in western North America. At three sites, soil and root samples from Bromus and Artemisia were collected. Sporulation was induced using trap cultures, and spores were identified using morphological characteristics. DNA was extracted from root and soil subsamples and amplified. Sequences obtained were aligned and analyzed to compare diversity, composition, and phylogenetic distance between hosts and sites. Richness of AMF species associated with Artemisia in cultures was higher than AMF species associated with Bromus. Gamma diversity was similar and beta diversity was higher in AMF associated with Bromus compared to Artemisia. AMF community composition differed between hosts in both cultures and roots. Two AMF species (Archaeospora trappei and Viscospora viscosum) associated more frequently with Artemisia than Bromus across multiple sites. AMF communities in Bromus roots were more phylogenetically dispersed than in Artemisia roots, indicating a greater competition for resources within the invasive grass. Bromus associated with an AMF community that differed from Artemisia in a number of ways, and these changes could restrict native plant establishment.

Native Lespedeza species harbor greater non-rhizobial bacterial diversity in root nodules compared to the coexisting invader, L. cuneata

Background and AimsLespedeza cuneata is a non-native invasive legume that alters the soil bacterial community, associates promiscuously with rhizobia, and benefits more from rhizobial interactions compared to coexisting native Lespedeza in North America. We tested the hypothesis that native congeners differ in their nodule bacteria associations compared to L. cuneata.MethodsPlots with high L. cuneata invasion, low L. cuneata invasion with native Lespedeza species present, and uninvaded plots where native Lespedeza species existed without L. cuneata were sampled. Nodules were collected from all Lespedeza species present, and Chamaecrista fasciculata, a common native annual legume. Bacterial DNA from nodules was isolated and sequenced.ResultsNodule bacterial composition differed significantly between hosts. L. cuneata nodules contained high frequencies of rhizobial DNA and low bacterial diversity, while native Lespedeza nodules contained lower rhizobial frequencies and higher non-rhizobial bacterial diversity. Specific non-rhizobial bacterial groups exhibited strong associations with native legumes and uninvaded sites.ConclusionsSignificant differences exist in the nodule bacterial composition between native legumes and an introduced congener. The mechanism(s) and ecological importance of these differences remain unknown. These differences in bacterial associations could influence not only the competitive ability of the invader, but recovery of invaded sites as well.

The Army Net Zero Waste Program and Its Implications for Energy

Net Zero Waste is one of three Net Zero Goals (the other two being energy and water) that the U.S. Army has implemented for various test installations that it operates. The Net Zero Waste program focuses on diversion of the wastes, which means that it seeks to reduce wastes first, then focuses on finding useful repurposing and recycling of materials currently managed as wastes. The ultimate goal of the Net Zero Waste program is to achieve a complete elimination of wastes managed by landfilling, although it is more likely that the end result will have a small amount that will have to be managed in this manner. This contrasts with current practice, which largely promotes landfilling wastes. Equations were derived and presented that allow for the calculation of net energy savings (or possible losses in some cases) by applying the Net Zero hierarchy to wastes currently managed by landfilling. Reviewing the range of wastes commonly found in municipal wastes indicates that most can be repurposed, reused, recycled or composted in some form or another. Another management option would focus on promoting waste to energy, and these are discussed in the document. A waste to energy focus maybe a very effective approach for forward operating bases, which are temporary bases used by the Army (and other services) for expeditionary operations.

Feasibility Study of Food Waste Co- Digestion at U.S. Army Installations

United States. Assistant Secretary of the Army for Installations, Energy and Environment. United States. Environmental Protection Agency. Office of Research and Development.

Material life cycle analysis for the reduction of waste generation at military installations

Abstract : In 2011, the U.S. Army implemented the Net Zero Initiative, which includes Net Zero Energy, Net Zero Water, and Net Zero Waste (NZW). A NZW installation is an installation that reduces, reuses, and recovers waste streams by converting them to resource value without using a landfill. To assist in that effort, this work reviewed the policies and initiatives aimed at reduction waste generation, discussed the challenges on the implementation of improvement efforts, and outlined existing research and operational needs to support more efficient operations and the achievement of Net Zero goals.