Gardner saltbush ecosystems are increasingly being invaded by halogeton, a competitive annual weed that increases soil surface salinity and reduces plant biodiversity. This study was established on the Flaming Gorge National Recreation Area, in the Ashley National Forest near Manila, UT to evaluate the ability of forage kochia, Russian wildrye, tall wheatgrass, Indian ricegrass and Gardner saltbush, in monocultures and binary mixtures with Gardner saltbush, to establish and compete in ecosystems dominated by halogeton. A dormant seeding, with and without prior disking, was conducted to determine the ability of plant materials to establish. A spaced-plant evaluation was used to determine the competitive ability of fully established plants by measuring halogeton densities at four 10 cm intervals (10-20, 20-30, 30-40, and 40-50 cm) distal from transplants. Gardner saltbush, tall wheatgrass, and Indian ricegrass did not establish or persist beyond the first year in either study. Conversely, Russian wildrye and forage kochia established and persisted, with Russian wildrye establishment higher (P ≤ 0.05) in the disked treatment (4.5 and 1.7 plants m-2, respectively) and no-till favoring (P ≤ 0.05) forage kochia establishment (2.0 and 0.8 plants m-2, respectively). Spaced-plants of these species reduced halogeton by 52% relative to the control. Furthermore, by the second year of evaluation, the competitive ability of Russian wildrye and forage kochia had extended to 50 cm distal from transplant. Transplant survival and halogeton frequency were highly correlated (r = -0.67, P = 0.0001), indicating the important of persistence. These results suggest that Russian wildrye and forage kochia can establish, persist, and compete with halogeton, thereby providing an opportunity for reclamation of halogeton-invaded areas. Conversely, direct restoration to Gardner saltbush and Indian ricegrass does not appear likely

The greenhouse frog, Eleutherodactylus planirostris, native to Cuba and the Bahamas, was recently introduced to Hawaii. Studies from other invaded habitats suggest that it may impact Hawaiian ecosystems by consuming and potentially reducing endemic invertebrates. However, there have been no studies on the greenhouse frog in Hawaii. The first component of this study was to conduct a diet analysis. We conducted a stomach content analysis of 427 frogs from 10 study sites on the island of Hawaii. At each site, we also collected invertebrates using two different sampling methods: leaf litter collection and sticky traps to characterize available resources. Greenhouse frogs consumed predominantly leaf litter invertebrates. Dominant prey items consisted of Hymenoptera: Formicidae (32.4%), Acari (19.2%), and Collembola (17.4%). Greenhouse frogs consumed more Formicidae than was measured in the environment. At one study site, we estimated there were 12,500 frogs ha-1 using mark-recapture methods and greenhouse frogs consumed 129,000 invertebrates ha-1 night-1 at this site. The second component of this study was to determine the distribution of the greenhouse frog on the island of Hawaii, with a male breeding call presence/absence survey at 446 points along the major road network. The greenhouse frog was detected at 61 sites (14%), and found mostly in lowland areas, in habitats of native shrublands and forests, nonnative forests, agricultural lands, and pastures on the southwestern and eastern sides of the island. We determined detection probabilities of the greenhouse frog and the invasive coqui frog, E. coqui. Detection probability of the greenhouse frog was low on the first two surveys and improved by the third survey. Detection probability of the coqui was higher than the greenhouse frog, but overall site occupancy estimates were similar for both species. Because the greenhouse frog appears to be as widespread as the coqui, we recommend that research be conducted to investigate its impacts ecologically to determine whether control efforts should also be aimed at this species.

Great Basin bristlecone pine (GBBP) (Pinus longaevaBailey) is one of the longest-lived organisms on Earth, and is one of the most highly fragmented high elevation conifer species. Throughout the Great Basin of the Intermountain West, GBBP are being impacted by changing disturbance regimes, invasive species, and climate change. To better understand the effects of climate variability and ecological disturbances in GBBP systems, three studies were designed and implemented. The first characterized the distribution of forest fuel in stands of GBBP and predicted how fuels may change under future climate scenarios. Using the Forest Inventory Analysis (FIA) plot variables of tree species, height, diameter at breast height (DBH), canopy base height (CBH), coarse (CWD) and fine (FWD) woody debris across elevational gradients, this study examined the effects of changes to fuel loading on predicted changes in fire behavior and severity. All classes of FWD decreased with elevation, and only 1000-hr fuels remained constant across elevational transects. This, combined with lower CBH and foliar moisture and increasing temperatures due to climate change, suggested increased fire potential at the GBBP treeline. The second study examined the role of volatile organic compounds (VOCs) and tree chemistry and their response to the environment. VOCs and within needle chemistry were collected and analyzed along elevational gradients near the northern and southern limits of GBBP. Random Forest analysis distinguished elevation using VOCs, with 83% accuracy, and identified the compounds most important for classification. Ordination revealed that temperature, heat load index, and relative humidity were each significantly correlated with VOCs. Within-needle chemistry provided less predictive value in classifying elevation (68% accuracy) and was correlated only with heat load index. These findings suggest that GBBP VOCs are highly sensitive to the environment. The final study explored the role of VOCs in host selection of mountain pine beetle (MPB). Mountain pine beetles oriented toward VOCs from host limber pine (Pinus flexilis James) and away from VOCs of non-host GBBP using a Y-tube olfactometer. When presented with VOCs of both trees, females overwhelmingly chose limber pine over GBBP. While there were only a few notable differences in VOCs collected from co-occurring GBBP and limber pine, 3-carene and D-limonene were produced in greater amounts by limber pine. There was no evidence that 3-carene is important for beetles when selecting trees, however, addition of D-limonene to GBBP VOCs disrupted the ability of beetles to distinguish between tree species. Climate change will impact how forests are managed and this research could provide insight into the mechanisms underlying the incredible longevity of this iconic tree species.

The interaction of land-use and climate can cause non-linear “state” changes in ecosystems, characterized by persistent differences in structure and function. Changes in land-use and climate on the Colorado Plateau may be driving many ecosystems toward undesired states where energy-intensive measures are required to return to previous states. Landscape classification systems based on “ecological potential” offer a robust framework to evaluate ecological conditions. Ecological sites are a popular landscape classification system based on long-term ecological potential and are widely used throughout the western US. Ecological sites have been described extensively for rangelands and woodlands on DOI Bureau of Land Management lands; however, they have yet to be described on USDA Forest Service (USFS) lands. In this thesis, I describe a statistical approach to ecological site delineation and the development of state-and-transition models, diagrams that illustrate ecosystem dynamics and responses to disturbances. In Chapter 2, I used a large inventory dataset and multivariate statistical procedures to classify plots based on life zone, soils, and potential vegetation, effectively delineating statistical ecological site-like groups. Most of the statistical ecological sites matched ecological sites already described by the USDA Natural Resources Conservation Service (NRCS). Additionally, I described one new ecological site that has not been described by the NRCS in the Colorado Plateau region. In Chapter 3, I examined empirical evidence for alternative states in mountain ponderosa pine (Pinus ponderosa Lawson & C. Lawson) and upland piñon-juniper ecosystems. Using multivariate statistical procedures, I found that plots cluster into groups consistent with generalized alternative states identified in a priori conceptual models. Additionally, I showed that ponderosa pine clusters were true alternative states and piñon-juniper clusters were not true alternative states because they were confounded by similarities in climate. Ponderosa pine clusters were differentiated by overstory ponderosa pine density and corresponded to three states: current potential, high fuel load, and reduced overstory. These results illustrate the range of ecosystem variability that is present throughout the study area and present evidence for alternatives states caused by historical land-use. This project is the first to propose ecological sites and state-and-transition models on USFS lands in this region. These techniques could be applied to areas that do not have formally described ecological sites and state-and-transition models and could help identify ecological sites that may have been overlooked using other means of delineation. Additionally, these methods can be used to evaluate the range of ecological variability throughout an area of interest and to improved understanding of ecosystem dynamics.

La biodiversité et le fonctionnement des écosystèmes sont des propriétés écologiques essentielles qui ont une incidence sur le bien-être humain. Des études sur la manière dont les deux biens sont affectés par les activités humaines et par le changement climatique fournissent les connaissances indispensables pour orienter la gestion des ressources naturelles. Les données de rétroobservation à long terme permettent de reconstituer l’histoire environnementale passée et offrent d’excellentes opportunités d’acquérir de telles connaissances. L'ADN sédimentaire est un outil émergent permettant de reconstituer la biodiversité passée détaillée au niveau du bassin versant, grâce à son excellente résolution taxonomique et à ses origines très localisées. Cependant, les études antérieures basées sur l'ADN sédimentaire utilisaient rarement le riche arsenal de méthodes d'analyse écologique numérique existantes, développées pour différents types de données écologiques. Dans la présente thèse, nous avons examiné les applications potentielles de telles méthodes sur des études basées sur l'ADN sédimentaire. Avec plusieurs exemples d’études, nous avons montré comment ces méthodes peuvent optimiser les connaissances acquises lors de l’analyse d’ensembles de données multiproxy comprenant des enregistrements sédimentaires d’ADN, de sédimentologie et climatiques. Malgré certaines limitations, l’analyse numérique basée sur l’ADN sédimentaire combinée aux enregistrements de proxies traditionnels est un outil puissant pour démêler les interactions complexes écosystémiques. Les futurs progrès méthodologiques dans l'analyse de l'ADN et les méthodes numériques sont prometteurs pour fournir une compréhension inestimable sur les facteurs de changement de la biodiversité et du fonctionnement des écosystèmes à grande échelle spatiale et temporelle. / Biodiversity and ecosystem functioning are crucial ecological properties that impact human welfare. Studies on how both properties are affected by human activities and by climate change provide indispensable knowledge to guide natural resource management. Long-term retro-observational data allow to reconstruct past environmental history and offer excellent opportunities to gain such knowledge. Sedimentary DNA is an emerging tool to reconstruct detailed past biodiversity in catchment level, thanks to its excellent taxonomic resolution and highly localized origins. However, previous studies based on sedimentary DNA rarely utilized the existing rich arsenal of numerical ecological analysis methods, which are developed for various types of ecological data. In the present thesis we reviewed the potential applications of such methods on sedimentary-DNA-based studies. With several example studies, we showed how these methods can maximize the knowledge gained from the analysis of multiproxy datasets that included sedimentary-DNA-, sedimentological- and climate records. Despite some limitations, numerical analysis based on sedimentary DNA combined with traditional proxy records is a powerful tool to unravel complex ecosystemic interactions. Future methodological advancements in both DNA analysis and numerical methods are promising to provide invaluable understanding over the drivers of changes in biodiversity and in ecosystem functioning across large spatial and temporal scales.

No description available.

Research Background: Climate change poses a core threat to the current and future welfare of society. Sub-Saharan Africa is particularly susceptible to challenges associated with climate change, most of which are bound to have large-scale societal impacts. Fortunately, Grand Challenges (GCs) can also enable opportunities for sustainable entrepreneurship to emerge. As entrepreneurs work in larger interrelated ecosystems, it is noteworthy to explore the utilization of ecosystems to develop sustainable ventures that address GCs. Current research has not addressed the interplay between external enablers and entrepreneurial ecosystems, especially in the Sub-Saharan context. The focus of this study is to explore how sustainable entrepreneurs acted on GCs in the pursuit of venture opportunities, and how ecosystems were utilized to foster the development of entrepreneurial agents and their ventures. Research Purpose: The purpose of this research is to identify how GCs facilitate sustainable entrepreneurship in Sub-Saharan Africa, given the interaction between entrepreneurs, their ecosystems, and climate change-associated GCs. Method: The research paradigm for this study follows critical realism. Meaning, we question the nature of reality as inherently multilayered and align with epistemic relativism. An explorative interview-based study was adopted for our methodology. We sampled our interview candidates purposively through the formation of several criteria. In total, we collected data from 20 semi-structured interviews through online platforms. We analyzed our data by interpreting principles of thematic analysis and the theory- building approach, to connect empirical themes to theoretical constructs. Conclusion: The results for this study show that sustainable entrepreneurs act on a wide variety of GCs. Within ecosystems, we noticed that sustainable development, cultural belief systems, educational infrastructure, governance, and resource accessibility influence the potential for ecosystems to develop. Specifically, we adopted three dimensions in which these pillars have influences: the entrepreneurial, communal, and structural level. The findings indicated that the scope of external enablers is fluid due to ecosystem interactions. Moreover, opacity and agency-intensity of enabling mechanisms can be reduced by developing entrepreneurial ecosystems. We also noted that entrepreneurs themselves can take on the role of ecosystem-builders. Our findings revised current understandings of sustainable entrepreneurship and redefined the concept to create a more inclusive label.

Ecosystems respond to stress factors that may have a natural or anthropogenic origin. Natural stress factors include flood, wildfire, drought, insect infestations, etc. and anthropogenic stress factors include pollution, land cover changes, and the introduction of alien invasive species. These stressors can degrade ecosystems and result in biodiversity loss and lowered resilience. In this thesis, I investigate the spatial and temporal dynamics of ecosystem stress caused by natural and anthropogenic factors in both aquatic and terrestrial ecosystems. The large study areas and long-term changes in my research have mandated the use of Remote Sensing (RS) and Geographic Information Systems (GIS) techniques in ways that have not been previously considered in ecological studies. In the first two chapters, I developed new approaches to monitor Phragmites australis, one of the most aggressive alien plant species that has invaded wetland ecosystems throughout N. America, as well as roadside ditches where management is costly and logistically challenging. I have developed innovative methods to accurately map invasive Phragmites under two conditions: 1) when plant biomass and densities are high so that managers can evaluate the effectiveness of treatment methods and 2) when plant biomass and densities are small and sparse so that these stands can be quantified and eradicated. I found that freely available, low to moderate resolution satellite imagery (Landsat 7/8 and Sentinel 2), acquired in late July or early August, can be used to produce highly accurate maps of dense Phragmites populations. I also found that commercial satellite imagery (WorldView 2/3) can be used to map Phragmites in the early stages of invasion and when plants have regenerated following herbicide treatment. In the latter half of my thesis, I examined how pre-fire canopy species composition and forest health influence the response of boreal forests to wildfires in Alberta, Canada. Forest fires occur naturally in boreal forests and usually affect very large spatial extents that remove accumulated fire fuel from the system. Following these outbreaks, the forests will regenerate and eventually become restored to their initial state. Climate-change induced droughts and flooding may change the frequency and location of these forest fires. To quantify the burn severity of each fire, I used Landsat images to calculate the differenced Normalized Burn Ratio (dNBR); then combined dNBR for all affected areas to develop the Standardized Burn Impact Score (SBIS), which quantifies the average impact of each fire based on the size of the burned area and the mean burn severity per pixel. In general, pre-fire dominance of coniferous species (jack pine and spruce) led to higher SBIS values while pre-fire dominance of broad-leaved species (aspen, birch, and poplar) led to lower values. Mean burn severity and SBIS values increased significantly when fire outbreaks occurred at a distance of 1 km or greater from water features (e.g. lakes, rivers, streams, wetlands). I also investigated the post-fire recovery process using indices of vegetation health and accounting for the effect of distance from the water features with respect to different levels of human activity. My results show that the post-fire recovery patterns are altered due to human activities and can affect the long-term fire regimes in boreal forests of northern Alberta. Overall, my thesis has advanced the use of novel remote-sensing techniques to study ecosystem stress factors on wetland and boreal ecosystems in Canada. / Thesis / Doctor of Philosophy (PhD) / Ecosystem stress is caused by natural or anthropogenic factors and results degradation of ecosystems. I investigated the spatial and temporal dynamics of ecosystem stress on aquatic and terrestrial ecosystems using Remote Sensing and Geographic Information Systems techniques. I mapped Phragmites australis, a notorious invasive grass, in wetlands to aid the Phragmites management programs. My research shows that images collected in late summer or fall provide high Phragmites mapping accuracy. Furthermore, I successfully mapped small, low-density Phragmites stands in the early stages of invasions. I also investigated the pre-and post-fire vegetation dynamics in the boreal forests of Alberta. I show that the species composition and water features influence the burn severity. The human influence on these ecosystems alters the natural post-fire vegetation recovery processes. Overall, my thesis advances the use of novel remote-sensing techniques to investigate the ecosystem stress factors on wetland and boreal ecosystems in Canada.

Dags att kasta loss? (Time to sail away?) explores the area of Smögen, Bohuslän, Swedenfrom a perspective of visual communication and sustainable tourism. As a person with aconnection to the area, this project grew from a wish to care for its present and future. Inthe beginning of the project, I only knew I wanted to use my role as a visual communicatorto protect and teach of the local ecosystems by growing curiosity and responsibility withintourists visiting during high season. Through the help of local collaborators, I could latersteer the focus towards littering by boat tourists as it is an ongoing problem around one ofthe most visited attractions; Smögenbryggan. Using storytelling and easily recognizableelements of Smögen as tools, the result is an illustrated sign highlighting the problem andpotential consequences of littering in the area. It aims to leave the target group with a senseof self-awareness in their inhabiting of the space and a sustainable mindset to reduce litteringin the water.

The thermotolerance, an adaptive phenomenon that is accompanied by the phenotypic plasticity which is the adjustment of physiology, biochemistry and metabolism of every cellular function by the hidden mechanism. Mitochondrion, the powerhouse of the cell that determines the functional integrity of every cellular homeostasis and functional phycological processes should provide its association in regulating the thermotolerance as well. This study assessed the mitochondrial function in regulating and determining the limit of thermo tolerance in the Daphnia magna of different geographical regions of the world, mainly sub grouped as temperature tolerant clones (IL) and temperature sensitive clones (GB). The acclimation effects or the adjustment of the preexisting biological properties help the organism adjust its biological processes to the changing habitat to maintain the cellular functional integrity. The clonal divergence as well as the acclimation show a clear pattern in limiting the thermotolerance and the prediction is the temperature tolerant clones should show higher adjustment of the mitochondrial function than temperature sensitive ones. We hypothesize that the damage in the mitochondrial membrane integrity by different mito-toxins should decrease the heat tolerance by decreasing the membrane potential and fluidity. The integrated mitochondrial function was assessed in acclimated clones by using the molecular studies as well as observation of behavioral and phenotypic plasticity. Due to the specific effects of each mito-toxins (CCCP, NaN3 and DNP) on different complexes (I-IV and ATP synthase) in ETC, we determined the mitochondrial membrane integrity by the Rhodamine 123 alongside with the lactate assay for measuring the mitochondrial integrity. Among all these three mito-toxins, CCCP show significant effect on limiting the heat tolerance. The lower lactate accumulation was observed in the temperature-tolerant clones acclimated in cold temperatures (18°C) which indicates the higher mitochondrial adjustment than the temperature sensitive clones. The concluding remark is that thermal tolerance is determined by the adjustment of mitochondrial function which accompanied with the adjustment to the mitochondrial respiration as well as the adjustment to membrane potential and fluidity.