Leaf litter is a major nutrient source for aquatic detrital food webs, fueling the microbes and macroinvertebrates that colonize it. Litter is especially important as a nutrient source for macroinvertebrates in headwater streams that tend to have lower primary production than higher-order stream systems. Understanding how litter decomposition and macroinvertebrates interact at large scales facilitates predictions about how stream ecosystems will change over space and time with regards to allochthonous nutrient inputs. We utilized a subset of the National Ecological Observatory Network's wadeable stream sites to deploy a litter pack study across the United States and Puerto Rico to determine the controlling factors for litter decomposition and associated macroinvertebrate assemblages, abundances, and species richness at a national scale. We found that litter species was the most important contributing factor to litter decomposition, and despite litter decomposition differences from stream to stream, the relative differences in decomposition rate between litter types was very similar. Stream identity, temperature, and flow also played roles in affecting decomposition patterns. In contrast to litter decomposition, litter species did not significantly contribute to variation in macroinvertebrate assemblages, abundance, or species richness, though environmental variables did impact abundance and species richness. These results suggest that there is functional redundancy in aquatic detritivore communities at large scales, and that the assemblages colonizing different species of leaf litter–despite being similar–might be functioning differently.

Deadwood, characterized as both downed woody material (DWM) and standing and dead stems, i.e., snags, is a significant component of terrestrial forest ecosystems. Deadwood amount and structure may influence potential wildfire hazard by altering combustible DWM mass and creating fuel structures that increase fire intensity and spread. Deadwood is also critical to carbon storage and nutrient cycling and may vary based upon the size classes of individual deadwood pieces. Lastly, deadwood structural variability has been found to positively affect species richness in bees, salamanders, birds, and small mammals, such as shrews and woodland mice. However, in the Mid-Atlantic Piedmont, there are no accessible tools to rapidly estimate deadwood of long unmanaged second growth forests to help inform future management decisions. Management agencies within this region, such as the National Park Service, may benefit from a greater understanding of the potential factors that influence deadwood accumulation, retention, and decomposition. Therefore, a project was funded by the National Park Service to investigate deadwood dynamics at Prince William Forest Park (PRWI). From May to August 2023, a deadwood inventory was conducted using planar intercepts nested within fixed radius plots along the gradient of forest cover types, aspect, elevation, and soil orders found within PRWI. Forest cover type was significant in the generalized linear model for percent dead basal area, total DWM, fine woody material, litter, and duff mass. The Virginia pine (Pinus virginiana) forest cover type had the highest percent dead basal area and total DWM mass per hectare. Elevation, aspect, and soil order were not significantly related to percent dead basal area, total DWM, 1,000 hr, fine woody material, litter, and duff mass. Data from this study may serve as a baseline for similar second growth forests of the mid-Atlantic Piedmont. / Master of Science / Visitors to Prince William Forest Park (PRWI) in eastern Virginia have voiced concern about forest health within PRWI. The perception of a high number of standing and dead stems, or snags, and a high number of decaying logs, branches, and twigs on the ground has been a focal point for visitors. Some perceive the dead material on the ground as a potential source of fuel for wildfires. Others perceive the potential hazard to humans along trails and vistas if snags were to fall. However, snags and downed woody material, known as deadwood, are critical components of forests because they store carbon and nutrients long-term and may provide habitat and resources for many wildlife species. Many other heavily used recreation locations in the eastern US face similar deadwood and forest health challenges. To respond to this, we assessed deadwood in PRWI to determine how it may be distributed differently across the variety of landscape features that are present within the park. We found the amount of total downed and dead material on the forest floor increased as the percentage of trees that were standing and dead increased. The amount of dead material on the ground was greatest for the Virginia pine (Pinus virginiana) forest community type, whereby PRWI's stands have reached their life expectancy. Prince William Forest Park's managers and those elsewhere at similar locations throughout the eastern US may benefit from this information as they seek to evaluate the status of their resources, manage those resources, and provide thoughtful messaging to the public regarding the significance and maintenance of deadwood as an ecosystem resource.

The aim of the study was to determine how litter affects the image of the environment and the animals at the Johannesburg Zoo, situated in the Northern part of Johannesburg, as perceived by various stakeholders. Furthermore, effectiveness of the educational awareness programmes developed and currently being presented at the Zoo were assessed. The central themes of the research on the issue of litter in a conservation area included the current status of litter in the Johannesburg Zoo, the perception of stakeholders frequenting or living in the vicinity of the Zoo and the nature and effectiveness of educational programmes presented at the Zoo. The stakeholders included visitors (n=332), employees (n=20) and others who represented the Zoo and people from the neighbouring Forest Town. It was possible to collect data on the premises while the Zoo was in full operation. The data-collection tools included two questionnaires (for visitors and employees) and interviews (other stakeholders), as well as a reflective recall of eight years of hands-on experiences and observations of a current curator at the Zoo. The latter served as a situation analysis of the Zoo to provide a backdrop for exploring the litter problem and served as background for designing the data-collection tools. The data of the survey conducted with questionnaires was quantitative in nature and was analysed descriptively in form of frequencies and percentages. The qualitative data gathered by means of the interviews were analysed and described against the experiences, beliefs and contact with the Zoo of the specific stakeholder. The educational programmes were described and the content assessed based on the effectiveness regarding litter minimisation information. The situation analysis revealed some tragic consequences of littering at the Zoo. It became clear that educating the public was a necessity to provide knowledge in such a way that it would inculcate a spirit of caring about and valuing the environment and the animals. All stakeholders identified that the Zoo has a serious litter problem and that the signboards needed more specific litter control messages and should be placed strategically so that they are noticed. Although the number of dustbins were sufficient, their distribution and placement in and around the Zoo were not effective. Educational programmes were considered by all to be the answer to the litter problem if the content could be expanded to include information on the consequences of and the legislation on littering. Recommendations regarding litter management for Johannesburg Zoo and for further investigation were suggested. / Geography / M. Sc. (Geography)

published_or_final_version / Geography and Geology / Master / Master of Philosophy

Thesis (Ph. D.)--Oregon State University, 2009. / Printout. Includes bibliographical references (leaves 118-124). Also available on the World Wide Web.

The aim of the study was to determine how litter affects the image of the environment and the animals at the Johannesburg Zoo, situated in the Northern part of Johannesburg, as perceived by various stakeholders. Furthermore, effectiveness of the educational awareness programmes developed and currently being presented at the Zoo were assessed. The central themes of the research on the issue of litter in a conservation area included the current status of litter in the Johannesburg Zoo, the perception of stakeholders frequenting or living in the vicinity of the Zoo and the nature and effectiveness of educational programmes presented at the Zoo. The stakeholders included visitors (n=332), employees (n=20) and others who represented the Zoo and people from the neighbouring Forest Town. It was possible to collect data on the premises while the Zoo was in full operation. The data-collection tools included two questionnaires (for visitors and employees) and interviews (other stakeholders), as well as a reflective recall of eight years of hands-on experiences and observations of a current curator at the Zoo. The latter served as a situation analysis of the Zoo to provide a backdrop for exploring the litter problem and served as background for designing the data-collection tools. The data of the survey conducted with questionnaires was quantitative in nature and was analysed descriptively in form of frequencies and percentages. The qualitative data gathered by means of the interviews were analysed and described against the experiences, beliefs and contact with the Zoo of the specific stakeholder. The educational programmes were described and the content assessed based on the effectiveness regarding litter minimisation information. The situation analysis revealed some tragic consequences of littering at the Zoo. It became clear that educating the public was a necessity to provide knowledge in such a way that it would inculcate a spirit of caring about and valuing the environment and the animals. All stakeholders identified that the Zoo has a serious litter problem and that the signboards needed more specific litter control messages and should be placed strategically so that they are noticed. Although the number of dustbins were sufficient, their distribution and placement in and around the Zoo were not effective. Educational programmes were considered by all to be the answer to the litter problem if the content could be expanded to include information on the consequences of and the legislation on littering. Recommendations regarding litter management for Johannesburg Zoo and for further investigation were suggested. / Geography / M. Sc. (Geography)

Plast påverkar vårt samhälle i stor utsträckning och har hjälpt till att utveckla nya förbättringar och redskap i vår vardag. Trots alla bra egenskaper med plaster har några oönskade effekter kommit till ytan med negativ påverkan på miljön. Detta examensarbete undersökte hur plastmaterial bryts ned av vittring utanför den svenska västkusten. Plastmaterialen undersöktes med hjälp av Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC) och Scanning Electron Microscopy (SEM) för att fastställa om kemisk nedbrytning sker efter 12 månader. Följande frågor stod i fokus: Vilka plaster har brutits ned, och i vilken utsträckning? Hur har plastens egenskaper förändrats? Vilka förutsättningar har de olika plastmaterialen för nedbrytning på stränder, och vilka faktorer påverkar nedbrytningen? Resultatet indikerade att liten eller ingen detekterbar nedbrytning skett på proverna efter 12 månaders vittring genom FTIR analys. Några prover visade dock tecken på förändring i de fysiska egenskaperna vid DSC analys, vilket kan beror på nedbrytning. Trots detta resultat fanns det synliga tecken på fragmentering, fysisk skada från stress och yttre krafter, såsom sand- och vågtumling för EPS (Styrofoam), LD-PE (Candy Paper) och PP (Blårep). Fragmenteringens påverkan på havlsmiljön kunde dock inte bevisas i denna studie eftersom prover på sand eller vatten från området inte genomfördes. Detta gör att endast synliga indikationer på fragmentering var identifierbara, men inte bevisa att det bidragit till makro- eller mikroplaster i närmiljön. Samtliga plastmaterial i studien innehöll någon form av tillsatts så som stabilisatorer. Eftersom endast små variationer förekommer i analysen av plastmateralen kunde det antas att tillsatserna och stabilisatorerna i materialen var effektiva i att hindra polymererna från nedbrytning under 12-månaders vittring. / Plastic has greatly impacted our society today and helped develop new improvements and implements in the daily lives. Despite all the good things, some undesirable impacts have also been discovered, which have been shown to impact the climate negatively. This thesis was to investigte how plastic degrades when weathered outside the  Swedish West Coast. The plastic materials were analysed using Fourier Transform Infrared Spectroscopy (FTIR), Differential Scanning Calorimetry (DSC), and Scanning Electron Microscopy (SEM) to determine whether degradation had occurred after 12 months. The following questions were at focus: What plastics have been degraded, and if so, which to the greatest extent? How have the properties of the plastic changed? What were theprerequisites for the different plastic materials for degradation on the shoreline, and what factors are affecting the degradation? The results indicated that the samples had little to no detectable degradation regarding the FTIR analysis after 12 months of weathering. Some of the samples showed a change in the physical properties from the DSC analysis, which could indicate degradation. Despite the result of degradation extent, there were clear signs of fragmentation, physical damage from stress, and external forces, such as rock and wave tumbling for EPS (Styrofoam), LD-PE(Candy Paper) and PP (Blue Rope). Fragmentation was not proven since no soil or water samples were made at the wethering site. This made the fragmentation only a visible parameter based on the samples after weathering, not proving that micro- or macro-plastic has been washed out in the ocean. All of the plastic materials used in the study were produced with some sort of additive, such as stabilisers. Since only small variations were shown in the analysis of the plastic materials, it can be assumed that additives and stabilisers were effective because there was no clear sign of degradation after 12 months of weathering.

The effects of adding a biodegradable litter amendment (AmmoSoak), developed from steam exploded corncobs, to poultry litter prior to pyrolysis on the product yields and qualities were investigated. Mixtures of litter and AmmoSoak were pyrolyzed in a bench-scale fluidized bed reactor. The objective of the second phase was to start-up a pilot-scale fluidized bed reactor unit. The poultry litter had a lower higher heating value (HHV), higher moisture, ash, nitrogen, sulfur, and chlorine contents than AmmoSoak. Analysis of the poultry litter indicated a mixture of volatiles, hemicelluloses, cellulose, lignin, ash, and proteins. AmmoSoak had a simpler composition than the litter; mainly hemicelluloses, cellulose, and lignin. Bench-scale studies indicated that adding AmmoSoak affected the yields and characteristics of the products. Addition of Ammosoak increased the bio-oil and syngas yields and decreased char yields. Adding AmmoSoak to the feed decreased the pH, water contents, initial viscosity, and the rate at which the viscosity increased with time, while densities and HHVs increased. The addition of Ammosoak to poultry litter also increased the carbon and oxygen contents of the boi-oils while nitrogen, hydrogen, sulfur, chlorine and ash contents decreased. A pilot-scale fluidized bed reactor was designed, constructed, installed and investigated for the pyrolysis of poultry litter. Fluidization and thermal equilibrium of the reactor were successfully demonstrated. The reactor was heated by combustion of propane. To ensure complete combustion, the combustion water was collected and compared to the stoichiometric yield. Complete combustion was achieved. Bio-oil yields on the pilot scale were lower than those obtained on the bench-scale pyrolysis unit. The water soluble fractions of the bio-oils were rich in oxygen. Water insoluble fractions were rich in carbon and ash. / Master of Science

Plastic deposition in hydrological systems is a pervasive problem at all geographic scales from loci of pollution to global ocean circulation. Much attention has been devoted to plastic deposition in marine contexts, but little is known about inputs of plastics into local hydrological systems, such as streams. Any attempt to prevent plastic litter must confront people’s behaviors, so archaeological concepts are used to distinguish between various cultural inputs (e.g., littering) and non-cultural forces (e.g., stream transport) that affect litter patterns on the landscape. Litter surveys along Hickory Creek in Denton, TX, are used to assess these factors.

As matas riparias tem efeitos positivos sobre a qualidade da água em rios de baixa ordem. O cultivo e a substituição de plantas de espécies nativas por espécies exóticas, tem efeitos e impactos significativos na biodiversidade de ambientes aquáticos e terrestre. O cultivo de Eucalyptus ocupam áreas de importância biológica e ambiental, causando impactos que ainda são pouco estudados, interferindo no funcionamento dos cursos de água que são dependentes do material foliar disponível nas margens dos rios como fonte de energia e nutrientes. O presente trabalho comparou a decomposição de folhas de espécies nativas (Inga marginata e Matayba elaeagnoides) e folhas de uma espécie exótica (Eucalyptus grandis) durante as estações seca e chuvosa, num riacho localizado no interior da Floresta Nacional de Ipanema, unidade de conservação situada no sudeste do estado de São Paulo. Para a comparação foi utilizado o método de litter bags usando sacos de malha grossa plástica de 10 mm de abertura, por períodos de no máximo 60 dias. Neste período também foi avaliada a colonização de macroinvertebrados bentônicos em cada um dos tratamentos testados. Entre as estações (seca e chuvosa), as perdas de massa foliar foram distintas, assim também existiram diferenças entre as espécies de plantas testadas (Inga marginata, Matayba elaeagnoides e Eucalyptus grandis), sendo sempre maior a perda nas folhas de Inga marginata, seguida das folhas de Eucalyptus grandis e Matayba elaeagnoides, e obtendo os maiores valores de perda de massa na estação chuvosa. Foram identificados 801 indivíduos que colonizaram nos três tratamentos testados na época seca e 556 indivíduos que colonizaram nos tratamentos na época chuvosa, existindo uma relação entre os valores de perda de massa e a abundância de organismos macroinvertebrados para cada um dos tratamentos, sendo os tratamentos com maiores perdas os que tiveram maiores valores de organismos colonizados. Os maiores valores de perda de massa para a folha de Inga marginata foi maior em comparação dos outros tratamentos além de apresentar a maior quantidade de macroinvertebrados aquáticos colonizados nas duas épocas avaliadas. As famílias mais representativas foram: Chironomidae, Hyalellidae, Gomphidae, Calamoceratidae, Leptophlebiidae e Elmidae. Assim os grupos funcionais com maior presença foram os grupos coletor e predador, não existindo diferenças significativas na presença destes grupos. O grupo fragmentador foi o terceiro grupo mais representativo para os três tratamentos e nas duas épocas avaliadas. Nesse tipo de ambiente tropical, a comunidade de fungos e bactérias é rico e diverso, fazendo esse processo biológico, importante para a transformação das folhas em um recurso de maior facilidade de assimilação para seu aproveitamento, tornando assim as folhas mais acessíveis para os organismos invertebrados. Deste modo, por exemplo transformando as folhas de eucalipto em um recurso, sendo estas folhas também acondicionadas para o consumo dos organismos e podendo-se constituir como um recurso adicional para a biota e os organismos se adaptando para a assimilação deste recurso. A presença de folhas de eucalipto pode influenciar na colonização dos organismos invertebrados, podendo interferir no processo natural da colonização de macroinvertebrados aquáticos e alterando a disponibilidade de nutrientes dentro das teias tróficas destes sistemas aquáticos. / The crumbled vegetation has positive effects on water quality in a low river. The crop plants and replacement of native species by exotic species, has significant effects and impacts on biodiversity of aquatic and terrestrial environments. Eucalyptus cultivation occupies areas of biological and environmental importance, causing impacts that are still poorly studied, interfering with the operation of the waterways that depend on available vegetable waste on the banks of rivers as a source of energy and nutrients. This study compared the decomposition of leaves of native species (Inga marginata and Matayba elaeagnoides) and leaves of an exotic species (Eucalyptus grandis) during the dry and rainy seasons in a river located within of the Floresta Nacional de Ipanema, conservation unit located in the southeastern state of São Paulo. For the comparison, the litter bags method was used. Thus, networks of plastic coarse mesh with an opening of 10 mm maximum were used for periods of 60 days. In this period the colonization of bentic macroinvertebrates in each of the treatments was also evaluated. Between the seasons (dry and rainy), losses of plant mass were different among different species of evaluated plants (Inga marginata, Matayba elaeagnoides and Eucalyptus grandis), considering that the loss of leaves of Inga marginata was higher, followed by the Eucalyptus grandis and Matayba elaeagnoides leaves. As a result, the loss of mass in the rainy season was evident. Thus, 801 individuals that colonized the three treatments evaluated in the dry season and 556 individuals that colonized treatments in the rainy season were identified. As consequence, there is a relationship between the values of loss of plant material and abundance of macroinvertebrates organisms for each of the treatments. The treatments with higher losses those who had higher values of colonized organisms. The largest mass loss values for Inga marginata sheet was higher in comparison of other treatments as well as presenting the greatest amount of aquatic macroinvertebrates colonized in the two seasons evaluated. The most representative families were: Chironomidae, Hyalellidae, Gomphidae, Calamoceratidae, Leptophlebiidae and Elmidae. Thus, the functional groups with the largest presence were collectors and predators groups, with no significant differences in the presence of these groups, the shredder group was the third most representative group for the three treatments and two periods evaluated. In this type of tropical environment, the community of fungi and bacteria is abundant and diverse, making of this biological process, an important aspect for the transformation of leaves in a resource ease of assimilation for its use, allowing these to become more accessible for invertebrate organisms. Considering the previous information, this allowed the Eucalyptus leaves transform in a resource available for consumption of organisms and being able to be as an additional resource for biota and organisms adapting to the assimilation of this resource. Thus, the presence of Eucalyptus leaves can influence the colonization of invertebrate organisms, it may interfere with the natural process of colonization of aquatic macroinvertebrates and altering the availability of nutrients in the food chains of these aquatic ecosystems.