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Modeling species of conservation concern, such as those that are rare, declining, or have a conservation designation (e.g. endangered or threatened), remains an activity filled with uncertainty. Species that are of conservation concern often are found infrequently, in small sample sizes and spatially fragmented distributions, thereby making accurate enumeration difficult and traditional statistical approaches often invalid. For example, there are numerous debates in the ecological literature regarding methodological choices in conservation-based models, such as how to measure functional traits to account for ecosystem function, the impact of including rare species in biological assessments and whether species-specific dispersal can be measured using distance based functions. This thesis attempts to address issues in methodological choices in conservation-based models in two ways. In the first section of the thesis, the impacts of methodological choices on conservation-based models are examined across a broad selection of available approaches, from: measuring functional diversity; to conducting bio-assessments in community ecology; to assessing dispersal in metapopulation analyses. It is the goal of this section to establish the potential for methodological choices to impact conservation-based models, regardless of the scale, study-system or species involved. In the second section of this thesis, the use of consensus methods is developed as a potential tool for reducing uncertainty with methodological choices in conservation-based models. Two separate applications of consensus methods are highlighted, including how consensus methods can reduce uncertainty from choosing a modeling type or to identify when methodological choices may be a problem.

Glutathione (GSH), a 3-amino acid compound is ubiquitously expressed in eukaryotic cells and is the most abundant low molecular weight thiol. The importance of GSH is highlighted by its multitude of effects. Within the vascular wall GSH plays a crucial role as an intracellular antioxidant and it possess the ability to act as a signalling intermediate and store for nitric oxide (NO). The importance of NO and its role in vascular wall homeostasis is well recognized. Within the coronary circulation, NO is the primary dilator of many of the large arteries and the smaller arterioles. In addition to controlling coronary vascular tone, the importance of NO is highlighted by its antithrombotic, antihypertrophic, and antriproliferative effects. During instances of cardiovascular disease and normal aging, increases in the production of reactive oxygen species occur. A portion of the deleterious vascular effects of reactive oxygen species are believed to be due to reduction in NO bioavailability as a result of increased ROS-mediated destruction of NO. Altered GSH production in humans has been demonstrated to reduce endothelial function. Conversely, supplementation with GSH augments endothelium-dependent dilation. The mechanisms by which these alterations in GSH influence vasomotor function have not been resolved. The purpose of the studies within this thesis was to examine the impact of chronic and acute GSH modulations on coronary vascular resistance (CVR) and endothelium dependent dilation. In all experiments vascular reactivity was assessed in the isolated perfused rat heart. The advantage of this technique is that it allows the global coronary vasomotor functioning to be examined. Hearts were allowed to stabilize for 30 minutes to allow for the development of spontaneous coronary vascular resistance, followed by a bradykinin (BK) dose-response curve to assess endothelium-dependent dilation. The coronary circulation was then maximally dilated using an endothelium-independent agonist. In all cases BK-mediated dilation is expressed as a percentage of the endothelium-independent dilation. Chapter 2 of this document examines the chronic nature of GSH depletion and examines whether GSH depletion augments the influence of natural aging. Animals (mean age 33 and 65 weeks) were randomized to receive L-Buthionine-(S,R)-sulphoximine (BSO) in the tap water in order to inhibit GSH synthesis, or regular tap water (normal controls). Following 10 days of BSO treatment, ventricular GSH content was reduced in the BSO group compared to the control (0.182±0.021 vs 2.022±0.084 nmol/mg wet weight, p<0.05) and there was increased ventricular H2O2 content (1.345±0.176 vs 0.877±0.123 pmol/µg PRO, p<0.05). Baseline CVR was significantly reduced in the older animals compared to the adult animals (3.92±0.34 vs 4.76±0.20 and 3.67±0.24 vs 5.12±0.37 mmHg/ml×min-1 in the control and BSO treated groups, p<0.05). Conversely, in the presence of LNAME there was a significant increase in CVR in the adult BSO group (14.15±0.99, p<0.05) compared to all other groups. In the absence of LNAME, maximal dilation (percent endothelium-independent response) was reduced in the older animals compared to the adult animals (77±10.3% vs 95.0±1.0% for older and adult control and 92.7±4.5% vs 98.6±0.6% for the older and adult BSO, main effect of age). In the presence of LNAME the adult BSO group had a significantly reduced sensitivity (EC50) compared to all other groups (-7.39±0.09 Log M, p<0.05). Additionally, adult BSO treated animals had an increase in eNOS protein content. These results demonstrate that chronic thiol depletion resulted in an increased reliance on NO in the adult BSO group only. In chapter 3 the beneficial effects of GSH supplementation on BK mediated dilation were examined. Acute GSH was administered in the perfusate at either 0 (control) or with 10 µM for 2 reasons, 1) this concentration does not reduce basal coronary vascular resistance, allowing for a similar baseline CVR across conditions and 2) the 10 µM concentration is a physiologically relevant concentration of plasma/extracellular fluid GSH. The sensitivity to the endothelial agonist bradykinin was enhanced in the presence of GSH (-8.70±0.16 vs -7.94±0.06 LogM, p<0.01). The GSH effect was not dependent on NO production or utilization by soluble guanylate cyclase (sGC) as the enhanced dilation in the GSH group was maintained despite NOS (LNAME) and/or sGC inhibition. When the hearts were supplemented with a ROS scavenger TEMPOL, enhanced dilation was seen in the control group, but was not further enhanced in the GSH group. The requirement for ROS was best demonstrated when both the CON and GSH groups were supplemented with both TEMPOL and LNAME. This condition resulted in similar sensitivity (-7.76±0.19 vs -7.75±0.17 LogM, p>0.05) and area under the curve (182.33±12.70 vs 170±13.86, p>0.05) between GSH and CON. Thus, it was concluded that the effects of GSH administration requires the presence of ROS and exerts its effect in the microvasculature. The study presented in chapter 4 examined the effects of acute thiol modulation (depletion) on CVR and endothelium-dependent dilation. Previous reports have suggested that a reduction in intracellular GSH causes impaired NO production, and functional data support this contention. However, a majority of the data regarding the effects of thiol manipulation are from endothelial-removed vessels. The following agents were used to reduce GSH: the glutathione reductase inhibitor, BCNU; the thiol oxidizing agent, diamide; the thiol conjugating agent, ethacrynic acid (EA); and a thioredoxin inhibitor (CDNB). Preliminary data revealed that only CDNB (11.46±0.71 mmHg/ml×min-1) and EA (8.61±0.36 mmHg/ml×min-1) caused an elevation in CVR compared to the control (6.73±0.24 mmHg/ml×min-1). Conversely, Diamide and BCNU did not significantly affect baseline CVR, or the BK mediated responses. In the presence of EA, there was an overall blunting of the BK-response curve as observed by reduced EC50 (-7.85±0.07 Log M) and maximal dilation (90.8±1.8 %, percent endothelium-independent dilation) compared to the control group (-8.42±0.08 Log M and 97.7±1.6%). In the presence of CDNB the maximal dilation was 74.4±1.9% and the EC50 was -8.83±0.28 Log M. In addition to altering BK mediated responses, acute thiol depletion with all agents resulted in an increased minimal CVR with significant increases observed in the presence of CDNB and EA. There was a significant correlation with GSH:GSSG ratio and baseline (-0.547, p<0.05) and minimal CVR (r=-0.581, p<0.05). This study demonstrates that modulation of the GSH:GSSG ratio using a variety of agents with diverse mechanisms elicits differential responses within the vasculature. Specifically conjugation of GSH and inhibition of thioredoxin significantly alters BK mediated response, where as BCNU and dimaide did not. These results suggest that a modulation in the GSH:GSSG ratio impairs endothelium-dependent dilation and alters total dilatory capacity (baseline-minimal CVR) and thus may have implications for adequate tissue perfusion. Across all studies there was significant correlation between GSH and GSSG with both baseline and minimal CVR. Therefore it is likely that changes in overall glutathione content plays a role in determining baseline and minimal coronary vascular resistance. These results demonstrate the complexity that manipulations of GSH have on both CVR and endothelium-dependent dilation, and provide mechanistic insight into how changes in GSH alter coronary vascular resistance and endothelium-dependent dilation.

The Rhodophyta (red algae) are an ancient crown group of the Eukarya (ca. 1400-1500 million years), comprised of 5000 - 6000 species. Gametophytes of taxa excluding the speciose Class Florideophyceae are typically of very simple unicellular, filamentous or foliose morphologies. These simple morphologies are often homoplasious (resulting from convergent or parallel evolution) and can be indistinguishable among distinct taxa, leading to cryptic species. As a result, historical morphology-based taxonomy is often not congruent with evolutionary history. Intraspecific genetic variation is not yet characterized for non-Florideophyceae taxa. Here the intraspecific genetic variation was characterized for a locally endemic, morphologically distinct bangiophyte red alga, Bangia maxima Gardner using inter simple sequence repeat (ISSR) patterns from 91 individual filaments across seven local populations. A high degree of genetic variation was observed over very small distances (< 25 cm) and very little genetic exchange was observed between populations. It is possible that B. maxima is a true endemic species and its population dynamics may differ from other Bangia species. Metrics of sequence-based identification rely on genetic divergence among isolates to distinguish taxonomic units independent of morphology. Such metrics are especially useful for morphologically simple or cryptic species. The mitochondrial cytochrome oxidase c subunit 1 gene has been proposed for the Florideophyceae. An evaluation of this gene as a metric for non-Florideophyceae taxa was undertaken and limited utility was demonstrated in most lineages of Rhodophyta due to poor or inconsistent amplification and conflicts with nuclear and plastid phylogenies. Patterns of genetic divergence among taxa are used to infer evolutionary relationships. The nuclear ribosomal small subunit (nSSU rRNA) is the taxonomically broadest pool of gene sequence data for the Rhodophyta. The use of stochastic models of nucleotide evolution is the most common approach to inferring phylogenies using this gene, ignoring much of its evolutionary information as different characters that contribute to secondary structure (e.g. paired nucleotides) are treated independently. The incorporation of structural information leads to more biologically realistic evolutionary models increasing phylogenetic resolution. Parametric models incorporating structural information were used here to more fully resolve phylogenies for all known Rhodophyta lineages. Novel phylogenetic topologies were observed and well supported for each Class within the Rhodophyta resulting in a number of formally proposed or suggested taxonomic revisions. These include phylogenetic resolution of Rhodophyta Classes, support for the introduction of 11 genera within the Bangiales and support for various taxonomic revisions within the Florideophyceae previously proposed but not yet fully adopted. As structure evolves more slowly than its constituent sequence, secondary structure elements can further resolve evolutionary relationships, especially in lineages as old as the Rhodophyta. A novel encoding of secondary structure elements and subsequent multivariate analysis was performed for all known Rhodophyta nSSU rRNA gene sequences, reinforcing phylogenetic results. Computer programs developed for these analyses are publicly available. The analyses presented here significantly advanced understanding of the evolutionary distribution of cryptic species within the Rhodophyta. Furthermore, useful methods for the characterization of such species are presented, as is a demonstration of the utility of biologically realistic sequence models parameterizing nSSU rRNA structure in resolving ambiguous phylogenetic relationships. Most importantly, this work also represents a significant improvement toward taxonomy congruent with evolutionary history for the Rhodophyta.

Invasive species are one of many important environmental issues facing Canadians today. A great deal of research has explored both the scientific and social aspects of invasive species. However, the cumulative research has not yet thoroughly explored people’s thoughts and feelings about, or perceptions of, invasive species and the influence these may have on management of, or policy decisions regarding, invasive species. This thesis research project was designed to assess the attitudes and perceptions that high school students have towards invasive species and to determine to what extent learning about invasive species alters their connection with nature. The study group was comprised of students from four Grade 11 Environmental Science classes from three high schools within the city of Guelph, Ontario. The students received regular classroom instruction from their teachers covering the course content, including invasive species. Students also made weekly visits to a local nature centre, providing them with hands-on learning experiences related to the course content. Students responded to an 80-question survey that assessed their knowledge of local invasive species and attitudes towards them as well as students’ connection to nature. Their connection to nature was assessed using a modified version of the Connectedness to Nature Scale (Mayer & Frantz, 2004). The surveys were administered by the classroom teachers in October, 2010, prior to the presentation of instructional material covering invasive species and then again in December, 2010 when the presentation of instructional material concerning invasive species was complete. The results showed that the students’ knowledge of invasive species upon entering the course was quite low and each of the classes witnessed a significant increase in knowledge. The survey results did not reveal any change to the students’ connection to nature; however, they did reveal three underlying themes in students’ attitudes towards invasive species: a concern about invasive species as a threat or problem; feelings of acceptance towards invasive species; and feelings of anxiety about invasive species. These attitudes remained relatively unchanged after the course.

The horticultural industry is responsible for approximately half of the invasive plant introductions in North America. To reduce these introductions, voluntary initiatives are preferred over government regulations. This thesis aims to evaluate the effectiveness of two types of voluntary initiatives. At the gardener level, I investigated the effectiveness of alternative species promotion campaigns, called “Grow Me Instead” programs. Adult gardeners visiting the Royal Botanical Gardens in Hamilton, Ontario, as well as customers at two garden centres, participated in a conjoint analysis which measured their preferences for various traits of potential ground cover species. Results showed that gardeners generally prefer plant species having invasive characteristics, suggesting these programs may not be as effective as initially believed. At the retailer level, this study aimed to build upon the work done by Burt and colleagues (2007) to obtain further understanding of the relative strength of internal (ethical motivations) and external (legislation, stakeholder pressures and economic opportunities) factors for motivating participation in voluntary initiatives. Telephone interviews were conducted with 30 industry professionals from southern Ontario to assess their adoption of the St. Louis Voluntary Codes of Conduct. Results found that participation rates of industry professionals in southern Ontario were lower for every specific initiative than those interviewed by Burt et al. (2007). Industry professionals presently experience the most pressure to participate from a sense of personal responsibility and the desire to create a green business image. Pressure was significantly higher from these sources than from pressure from employees. Together these two studies identified several barriers to the efficacy of voluntary initiatives as well as some reasons for optimism. To ensure the success of future voluntary initiatives, efforts must be made to encourage these two groups to work together. Understanding how both retailers and gardeners respond to voluntary initiatives will assist in the development of more effective programs and lead to fewer horticultural invasive species introductions in the future.

Many diverse microbes have been detected in or isolated from glaciers, including novel taxa exhibiting previously unrecognized physiological properties with significant biotechnological potential. Of 29 unique phylotypes isolated from Victoria Upper Glacier, Antarctica (VUG), 12 were related to the poorly studied bacterial genus Hymenobacter including several only distantly related to previously described taxa. Further study of these microorganisms revealed genotypic, phenotypic, morphological and chemotaxonomic divergence from named species and suggested that they likely represent novel Hymenobacter species. These studies also indicated, however, that the systematics of Hymenobacter and related microorganisms is more complex than previously realized, and may exhibit poorly defined species boundaries due to cosmopolitan dispersal, significant rates of horizontal gene transfer and reintroduction of archived genotypes, e.g., from glacial ice. These processes are reflected in the carotenoid composition of Hymenobacter and related organisms, which includes several novel methyl- and xylosyl-derivatives of 2'-hydroxyflexixanthin with distributions indicative of horizontal gene transfer or differential gain and/or loss of terminal biosynthetic pathway steps. These processes have been previously underappreciated in assessments of microbial carotenoid diversity and suggest the need for fine-scale phylogenetic study of carotenoid distribution in other microbial taxa. Further comparative genomics-based evaluation of microbial carotenoid biosynthesis indicated its wide phylogenetic distribution and diversification, controlled by several lineage-specific modes of evolution including horizontal transfer, de novo enzyme evolution followed by differential gene loss, co-evolution with biochemically associated structures and elevated mutation rates. The latter especially interacts with horizontal transfer depending on metabolic pathway topology, exemplified by the evolution of purple bacterial carotenoid biosynthesis. Exploration of VUG microbial diversity, therefore, not only revealed novel taxa and biotechnologically interesting compounds but also spurred broader evaluation of the mechanisms of metabolic pathway evolution applicable to many other taxa and biochemical pathways. / Microbiology and Cell Biotechnology

Intensive Flächennutzung und Veränderungen von Klima und Standortbedingungen haben dazu geführt, dass mittlerweile 25 von 65 heimischen Heuschrecken-, Fangschrecken-, Schaben- und Ohrwurmarten als gefährdet oder ausgestorben gelten. Die Rote Liste enthält eine Artenliste und gibt einen Überblick über die Gefährdungssituation der einzelnen Arten. Bewertet werden Bestandssituation und der Bestandstrend.

Die Rote Liste gefährdeter Biotoptypen in Sachsen - in der zweiten, vollständig überarbeiteten Neuauflage - macht auf den Rückgang von Lebensräumen aufmerksam. Sie stellt eine notwendige Ergänzung zu Roten Listen gefährdeter Arten dar, indem die Komplexität der Lebensraumansprüche von Arten und ihre Interaktionen berücksichtigt werden.

This study focused on an invasive riparian reed grass, Arundo donax L., a clonal plant of the family Poaceae that is widely distributed in North America. Water availability, including water taken up from the roots locally or transported from the neighboring ramets, may affect the performance of A. donax in riparian zones. The first objective was to find out how moisture gradients affected the performance of A. donax in riparian zones. I measured leaf photosynthetic rate, leaf δ13C ratio, and plant growth-related parameters across two summer growing seasons at four transects perpendicular to the water course on the Rio Grande in South Texas. The second objective was to find out whether physiological integration existed in A. donax and how resource sharing, if any, affected plant growth. A rhizome severing experiment was conducted on five paired plots to compare growth-related parameters between plots with rhizomes severed and intact at 3, 7, and 11 weeks after treatment. Heavy water (δ 2H ~1800‰) was applied on three 1-m2 area over 3 successive days and rhizome samples were collected beyond the watering zone after 5, 24, and 48 hours of last watering. At short-term scales, A. donax performance was adversely affected by both drought and inundated conditions; over longer time scales, plant performance decreased as water availability declined in general, but biomass and stem density were similar across moisture gradients. I also found evidence of physiological integration in A. donax. Water was transported through interconnected rhizomes at least 3.5 m; transport distances averaged 1.67 m. Rhizome severing stimulated higher ramet production initially but over longer periods produced shorter thinner stems with lower flood tolerance. However, after 11 weeks of re-growth, plot-level biomass was similar between plots with severed and intact rhizomes. These results suggest that performance of A. donax is affected by water availability in riparian zones; however, clonal plant plasticity, water use efficiency, and clonal integration ameliorate impacts of water stress on the performance of A. donax. Such traits enhance its resource use, which could potentially increase competitive ability rate of establishment, and extent of this invasive species in heterogeneous riparian environments.