The goal of the Aquatic Indicators of Land Condition (AILC) project is to develop analytical tools that integrate land condition information with stream condition for improved watershed management within the United States Bureau of Land Management (BLM). Based on the goal of the AILC, two objectives for this study were: to determine the effect of four GIS-derived distance measurements on potential relationships between common BLM landscape stressors (mining and grazing) and changes in benthic macroinvertebrate community structure; and to assess the effectiveness of individual questions on a commonly-used Bureau-wide qualitative stream assessment protocol, the proper functioning condition (PFC) assessment. The four GIS distance measurements assessed for biotic relevance included: straight-line distance, slope distance, flow length, and travel time. No significant relationships were found between the measured distance to stressor and macroinvertebrate community structure. However, the hydrological relevance of flow length and travel time are logically superior to straight-line and slope distance and should be researched further. Several individual questions in the PFC assessment had statistically significant relationships with the final reach ratings and with field-measured characteristics. Two of the checklist questions were significantly related to the number of cow droppings. This may indicate a useful and efficient measure of stream degradation due to grazing. The handling and use of the PFC assessment within the BLM needs further documentation and examination for scientific viability, and the addition of quantitative measurements to the PFC in determining restoration potential would be desirable. / Master of Science

The Central Appalachian region is home to several resource-extraction industries, a host of globally unique aquatic wildlife species, and region-wide poverty. These overlapping circumstances make solving environmental issues in the region challenging. Of particular focus is the coal mining industry, both because of its prevalence and because of controversial methods of practice such as mountain top mining. One of the primary concerns in the region is the extirpation of sensitive aquatic macroinvertebrate species. Several studies have suggested the primary driver of this loss of biodiversity is due to increased conductivity in streams impacted by these mining practices. The reality is that several pollutant sources coexist in these Central Appalachian watersheds. Because of geographic isolation, many headwater communities lack proper sewerage and discharge directly into nearby waterways, compounding potential effects of upstream mining activities. Additionally, several legacy sites exist throughout the Appalachian region, both underground and surface mining in nature. To best mitigate ecological impacts of all of these pollutant types, relative contributions of each must be understood, as well as the nature of the pollution contributed by each. As a contribution towards this region-wide need for better information on pollution, the studies comprising this dissertation seek to better understand the composition of these different pollutant sources and their in-stream contributions to conductivity. The first paper found that these sources are indeed distinct in their inorganic ion make-up: surface coal mining was found to contribute primarily Ca, K, Ni, Se, and SO₄⁻², while untreated household waste (UHW) was primarily associated with P. HCO₃⁻ Mn, and Si were found to be associated with a legacy underground discharge. The second and third scientific studies included here analyzed conductivity's effect on Virginia Stream Condition Index (VSCI) versus other water quality and habitat parameters as well as the effect of specific ion suites on VSCI score. Findings indicated that excellent habitat extends species resilience against elevated conductivity, with passing VSCI scores found at conductivity in the 600-800 µs/cm range in cases of excellent habitat metric scores. Meanwhile, VSCI score suppression was highly related to surface mining-related inorganic ions (Ca, K, Mg, Ni, and SO₄⁻²), but also negatively correlated with ions related to UHW (P and Na). These results indicate the need for quantification of biological responses to specific ions in order to initiate targeted mitigate of pollutants in Central Appalachian watersheds. / Ph. D.

Prior studies have demonstrated Appalachian coal mining often causes elevated specific conductance (SC) in streams, and others have examined SC effects on benthic macroinvertebrate communities using point-in-time SC measurements. However, both SC and benthic macroinvertebrate communities exhibit temporal variation. Twelve Appalachian headwater streams with minimally impacted physical habitat and reference-quality physicochemical conditions (except elevated SC) were sampled ten to fourteen times each for benthic macroinvertebrates between June 2011 and November 2012. In situ loggers recorded SC at 15-minute intervals. Streams were classified by mean SC Level (Reference 17-142 S/cm, Medium 262-648 S/cm, and High 756-1,535 S/cm). Benthic macroinvertebrate community structure was quantified by the Virginia Stream Condition Index and other metrics. Structural metric differences among SC Levels and month of sampling were explored. Reference-SC streams exhibited significantly higher scores on most metrics, supporting previous findings that SC may act as a biotic stressor, even in streams lacking limitations from degradation of physical habitat or other physicochemical conditions. Temporal variation was greatest in Medium-SC streams, which had the most metrics exhibiting significant differences among months and the greatest range of monthly means for six metrics. Metrics involving % Plecoptera and/or % Trichoptera were not sensitive to elevated SC, as Leuctridae and Hydropsychidae exhibited increased abundance in streams with elevated SC. Best scores for benthic macroinvertebrate community metrics differed based on selected metric, SC Level, and month. Consequently, timing of sampling is important, particularly in streams with elevated SC because community metric scores may be impacted by dominant taxa life history patterns. / Master of Science

This study investigates the understudied abundance and habitat associations of bivalves in Mosquito Lagoon. Seagrass habitats were found to support the highest diversity of mollusks in earlier surveys (Mikkelsen et al., 1995). Twelve sites, including seagrass-vegetated, unvegetated, and seagrass-restored areas, were sampled in March and May 2024. Habitat characteristics, such as sediment composition and seagrass cover, were analyzed alongside bivalve populations. Across all sites, 6 genera were identified among 44 individuals. Overall abundance and diversity of bivalves collected were low in all sites, and most individuals were juveniles. Sediment characteristics influenced differences in diversity across site types, with restored sites composing of a mean of 68% disarticulated shell. Contrary to expectations, seagrass habitats did not support higher diversity or abundance compared to unvegetated habitats. Determining a revised profile of the bivalve community in Mosquito Lagoon and understanding habitat associations is important for improving water quality and restoration.

The Dallas-Fort Worth International (DFW) Airport is located in a densely urbanized area with one of the fastest-growing populations in the U.S.A. The airport property includes a large tract of "protected" riparian forest that is unique to the urban surroundings. This dissertation explores variables that influence the benthic macroinvertebrate community structure found in urbanized prairie streams that were initially assessed by the University of North Texas (UNT) Benthic Ecology Lab during four, non-consecutive biomonitoring studies (2004, 2005, 2008, and 2014) funded by the DFW Airport. Additionally, land use analysis was performed using 5-meter resolution satellite imagery and eCognition to characterize the imperviousness of the study area watersheds at multiple scales. Overall, flow conditions and imperviousness at the watershed scale explained the most variability in the benthic stream community. Chironomidae taxa made up 20-50% of stream communities and outperformed all other taxa groups in discriminating between sites of similar flows and urban impairments. This finding highlights the need for genus level identifications of the chironomid family, especially as the dominant taxa in urban prairie streams. Over the course of these biomonitoring survey events, normal flow conditions and flows associated with supra-seasonal drought were experienced. Prevailing drought conditions of 2014 did not negatively influence stream communities, allowing this study to capture the long-term natural (temporal) variability of urban prairie stream communities. Such long-term studies are imperative for discerning between stream impairment versus natural variation, especially as droughts become more frequent and severe.

Invasive species are often both ecologically and economically detrimental, particularly in freshwater ecosystems where direct and indirect impacts of invasion interact with pre-existing anthropogenic stressors to magnify consequences for native communities and habitats. Planktivorous silver carp (Hypophthalmichthys molitrix) are invasive in the Mississippi River watershed, where their daily consumption of detrital seston can total more than half their body mass, and where they outnumber all native species combined in some river reaches. Because of these astonishing abilities, silver carp can cause basal resource changes, altering the body sizes and abundances of native plankton communities upon invasion. Much research has focused on this outcome of silver carp proliferation, but investigation into other effects of their presence in invaded systems has not received the same attention. Despite the unique tendency of silver carp to experience species-specific mass-mortality events, for example, there is a dearth of peer-reviewed evaluation of the possible ecological consequences of these occurrences. To elucidate the effects of these events which can comprise hundreds of thousands of individuals, we determined how the decomposition of silver carp carcasses following mass-mortality events affected benthic invertebrate community composition and productivity using a mesocosm approach. Each mesocosm was subjected to either the presence or absence of a silver carp carcass over the length of an eight-week experiment. Carcass presence created anoxic conditions in the mesocosms and acutely increased benthic invertebrate biomass and benthic periphyton growth. While acute, changes to benthic conditions following silver carp mass-mortality events are likely to have long-term effects in both invaded freshwater systems and their surrounding terrestrial landscapes. Given the magnitude of die-offs, it is possible that these events could cause ecosystem-level alterations. Further research, therefore, is needed into the additional impacts that may follow carcass decomposition to quantify and predict outcomes associated with continued silver carp invasion.

A população de foraminíferos e tecamebas no SELCI evidenciou variação espacial, caracterizando alta dominância de hialinos e porcelanáceos no verão, e aglutinantes no inverno. Essa distribuição da microfauna estava associada a maior influência marinha dos setores externos e a forte influência do regime regional de chuvas nos setores internos. Constatou-se como bioindicadores a espécie Pararotalia cananeiaensis indicando o alcance da cunha salina nas porções internas do sistema, os miliolídeos indicando ambientes com renovação de águas marinhas e fluxos mais energéticos no sistema, o gênero Miliammina spp. e as tecamebas indicando ambientes de baixa salinidade. Através do Ic foi possível detectar o impacto do balanço entre as influências continentais e marinhas no sistema, com a intrusão salina sazonalmente distinta, devido às próprias condições regionais e geomorfológicas do sistema. Na tentativa de encontrar ambientes hipóxicos foi aplicado o IAE, porém este índice não gerou resultados satisfatórios neste sistema estuarino, visto que outros fatores representaram ser variáveis mais importantes do que a concentração de oxigênio dissolvido. O cálculo da BFAR foi testado revelando que a geomorfologia do SELCI foi um fator determinante na distribuição das espécies e que a BFAR foi uma medida qualitativa do fluxo de MO no sistema. Através das análises estatísticas multivariadas foi possível determinar as associações da microfauna, sendo estas condicionadas, nas duas campanhas, principalmente pelos fatores salinidade, substrato e profundidade. / The population of foraminifera and thecamoebians in the CILES (Cananéia-Iguape Lagoon Estuarine System) evidenced spatial variation, characterizing high dominance of hyalines and porcelanaceous during the summer and agglutinated in the winter. This microfauna distribution was associated to stronger marine influence in the outer sections and to strong regional pluviosity in the inner sections. The bioindicator species were Pararotalia cananeiaensis, evidencing the extent of the salt water wedge in the inner portion of the system, the miliolidae, indicating environments with renewal of marine water and more energetic fluxes in the system and the gender Miliammina spp. and thecamoebians indicating areas of low salinity. Trough the Ic it was possible to identify the impact of the balance between marine and fresh waters influence in the system, with saline intrusion seasonally distinct, due to the system\'s own regional and morphological conditions. An attempt to identify hypoxia areas was made using the AEI (Ammonia-Elphidium Index) test, however, this index did not reveal satisfactory results in this estuarine system, since other factors seem to be more representative than the dissolved oxygen concentration. The geomorphology of the CILES was proved to be a determinant factor in the distribution of the species through the BFAR (Benthic Foraminifera Accumulation Rate) calculation, which was also a qualitative measure of the flux of organic matter (TOC) in the system. Statistical analysis proved that the associations of microfauna, was driven, in both campaigns, by salinity, substract and depth.

Thesis (M.E.S.)--The Evergreen State College, 2007. / Title from title screen viewed (4/7/2008). Includes bibliographical references (leaves 49-56).

A população de foraminíferos e tecamebas no SELCI evidenciou variação espacial, caracterizando alta dominância de hialinos e porcelanáceos no verão, e aglutinantes no inverno. Essa distribuição da microfauna estava associada a maior influência marinha dos setores externos e a forte influência do regime regional de chuvas nos setores internos. Constatou-se como bioindicadores a espécie Pararotalia cananeiaensis indicando o alcance da cunha salina nas porções internas do sistema, os miliolídeos indicando ambientes com renovação de águas marinhas e fluxos mais energéticos no sistema, o gênero Miliammina spp. e as tecamebas indicando ambientes de baixa salinidade. Através do Ic foi possível detectar o impacto do balanço entre as influências continentais e marinhas no sistema, com a intrusão salina sazonalmente distinta, devido às próprias condições regionais e geomorfológicas do sistema. Na tentativa de encontrar ambientes hipóxicos foi aplicado o IAE, porém este índice não gerou resultados satisfatórios neste sistema estuarino, visto que outros fatores representaram ser variáveis mais importantes do que a concentração de oxigênio dissolvido. O cálculo da BFAR foi testado revelando que a geomorfologia do SELCI foi um fator determinante na distribuição das espécies e que a BFAR foi uma medida qualitativa do fluxo de MO no sistema. Através das análises estatísticas multivariadas foi possível determinar as associações da microfauna, sendo estas condicionadas, nas duas campanhas, principalmente pelos fatores salinidade, substrato e profundidade. / The population of foraminifera and thecamoebians in the CILES (Cananéia-Iguape Lagoon Estuarine System) evidenced spatial variation, characterizing high dominance of hyalines and porcelanaceous during the summer and agglutinated in the winter. This microfauna distribution was associated to stronger marine influence in the outer sections and to strong regional pluviosity in the inner sections. The bioindicator species were Pararotalia cananeiaensis, evidencing the extent of the salt water wedge in the inner portion of the system, the miliolidae, indicating environments with renewal of marine water and more energetic fluxes in the system and the gender Miliammina spp. and thecamoebians indicating areas of low salinity. Trough the Ic it was possible to identify the impact of the balance between marine and fresh waters influence in the system, with saline intrusion seasonally distinct, due to the system\'s own regional and morphological conditions. An attempt to identify hypoxia areas was made using the AEI (Ammonia-Elphidium Index) test, however, this index did not reveal satisfactory results in this estuarine system, since other factors seem to be more representative than the dissolved oxygen concentration. The geomorphology of the CILES was proved to be a determinant factor in the distribution of the species through the BFAR (Benthic Foraminifera Accumulation Rate) calculation, which was also a qualitative measure of the flux of organic matter (TOC) in the system. Statistical analysis proved that the associations of microfauna, was driven, in both campaigns, by salinity, substract and depth.

Altitudinal gradients in Sub-Antarctic freshwater systems present unique opportunities to study the effect of distinct environmental gradients on benthic macroinvertebrate community composition and dispersal. This study investigates patterns in biodiversity, dispersal and population genetic structure of benthic macroinvertebrate fauna across an altitudinal gradient between two watersheds on Navarino Island in southern Chile. Patterns in diversity, density, evenness and functional feeding groups were not significantly different across the altitudinal gradient in both the Windhond and Róbalo Rivers. Taxa richness in both rivers generally increased from the headwaters of the river to the mouth, and functional feeding group patterns were consistent with the predictions of the River Continuum Concept. Population genetic structure and gene flow was investigated by sampling the mitochondrial cytochrome oxidase I gene in two invertebrate species with different dispersal strategies. Hyalella simplex (Amphipoda) is an obligate aquatic species, and Meridialaris chiloeense (Ephemeroptera) is an aquatic larvae and a terrestrial winged adult. Contrasting patterns of population genetic structure were observed. Results for Hyalella simplex indicate significant differentiation in genetic structure in the Amphipod populations between watersheds and lower genetic diversity in the Róbalo River samples, which may be a result of instream dispersal barriers. Meridialaris chiloeense exhibited weak population structure but higher genetic diversity, which suggests this species is able to disperse widely as a winged adult.