A. Lee Foote

Odonates as biological indicators of grazing effects on Canadian prairie wetlands

Abstract.  1. Aquatic macro‐invertebrates have frequently been used as biological indicators in lotic environments but much less commonly so in lentic habitats. Dragonflies and damselflies (Order Odonata) satisfy most selection criteria for lentic bioindicators of grazing impacts.

AQUATIC INVERTEBRATE RESPONSES TO FISH PRESENCE AND VEGETATION COMPLEXITY IN WESTERN BOREAL WETLANDS, WITH IMPLICATIONS FOR WATERBIRD PRODUCTIVITY

Aquatic invertebrates are essential to wetland function, serving as the key trophic link between primary producers, fish, and waterfowl in boreal wetlands. We studied how both aquatic vegetation complexity and prevalence, and fish presence, could be used to predict the distribution of invertebrate biomass in 24 wetlands of the Western Boreal Forest (WBF). The percent volume occupied by aquatic plants was significantly positively associated with overall invertebrate biomass per liter (P = 0.009). Particular invertebrate functional feeding groups were correlated with types of aquatic macrophyte architecture; herbivorous invertebrate biomass (mg/L) was greater in more complex aquatic environments, and predatory invertebrate biomass was greater in environments with simple plant architecture. Wetlands inhabited by Brook Stickleback (Culaea inconstans) had reduced invertebrate biomass of the predatory, non-predatory (excluding omnivores), and gatherer/collector functional feeding groups. Gatherer/collector, predator, shredder, and piercer invertebrate groups were negatively correlated with dissected leaved plant dominance in those wetlands without fish. These invertebrate groups comprise the bulk of invertebrate protein available to nesting hen mallards and their ducklings. We suggest that the presence of stickleback and/or dominance of dissected leaved plants in the wetlands of the WBF results in decreased food supply for hatchling waterfowl.

Effects of Culverts on Stream Fish Assemblages in the Alberta Foothills

Abstract Watercourse-crossing structures are ubiquitous anthropogenic features in the Rocky Mountain foothills of Alberta. We performed physical and habitat assessments at 295 watercourse-crossing sites in 15 subbasins of the Athabasca River during the summer and early fall of 2007, 2008, and 2009, sampling for fish at 110 sites (32 bridges and 78 culverts). We used bootstrapping analysis to examine how several culvert parameters (hang height, outlet plunge pool depth, water velocity, length, and slope) altered the upstream abundances of eight fish species relative to those at reference bridge sites. Physical drops at the outlet (hang heights), slope, and outlet water velocities were the most important culvert parameters shaping non-sport-fish distributions. Some culvert types (e.g., hanging culverts) acted as complete barriers to burbot Lota lota and partially impeded the movements of spoonhead sculpin Cottus ricei, suckers Catostomus spp., and minnows (family Cyprinidae). For example, at culverts with h...

The interactive effects of herbivory and fire on an oligohaline marsh, Little Lake, Louisiana, USA

Herbivory and fire have been shown to affect the structure and composition of marsh communities. Because fire may alter plant species composition and cover, and these alterations may have an effect on herbivore populations or foraging patterns, an interactive effect of herbivory and fire may be expected. In this study, the effects of fire and vertebrate herbivory in a Louisiana oligohaline marsh were studied using small, controlled burns and animal exclosures. Mean total biomass was nearly 2 times greater in the plots protected from herbivory than in the plots subject to natural herbivory. Additionally, mean total biomass was over 1.5 times greater in the plots that remained unburned than in those that were burned. Two dominant perennial species,Spartina patens andScirpus olneyi, were negatively affected by herbivory, but two annual sedges,Cyperus flavescens andCyperus odorata, were positively affected. Burning reduced the aboveground biomass ofSpartina patens andBacopa monnieri. No species increased in biomass as a result of fire. No significant differences were found in species richness between herbivory treatments or between fire treatments. Although both herbivory and fire were found to cause significant changes in the vegetation, the interaction between herbivory and fire was not found to produce any significant effects in any test conducted.

Monitoring and Assessment of Wetland Condition Using Plant Morphologic and Physiologic Indicators

We created and evaluated indices of plant performance using plant morphological and physiological attributes and assessed their potential as wetland condition indicators by studying their consistency along a stress gradient. Based on Spearman coefficients, we selected promising morphological and physiological metrics that showed consistent responses along a physico-chemical stress gradient. Metrics consistently associated with wetland condition were ranked and combined into morphological (mPPI) or physiological Plant Performance Indices (phPPI). Six morphological metrics were able to discern between good and poor wetland conditions along the impact gradient and were thereafter combined into the mPPI. The resulting mPPI was found to be a strong indicator of stress and accurately identified degraded wetlands (rs = −0.52; P = 0.030). In contrast, most of the physiologic metrics showed lower correlations to the stress gradient. Consequently, the resulted phPPI had a lack of association with the stress gradient and failed to identify even heavily-impacted wetlands (rs = −0.30; P = 0.194). We conclude that the morphological characteristics of plants, the reliability of the mPPI, and its ability to simply and easily convey habitat information makes it worthy of further refinement and validation as a tool for evaluating mitigation and restoration efforts in wetlands.

Why an Oral Exam

Why do oral exams when written exams are the more typical for examinations? There is a very long tradition. Oral exams define the graduate’s expertise beyond a conventional test-taker by requiring immediate synthesis and collegial interaction with a group of qualified peers. Orals provide a way to appraise ethics, scholarship, critical thinking, communication, creativity, and confidence under pressure in a situation that mimics real work environment settings. Oral exams allow excellent students to deliver succinct, nuanced, interactive answers far better than simple written answers. These exams are profound teaching situations too, providing insight into collegial Socratic discussion of original research. The traditions, decorum and outcomes of oral exams are described.

Positioning, Personality, and Presumption

Visualize how you are being perceived by committee members. Give full answers but know when to stop. Be conversant as a respectful equal. Don’t over-react with subservience, bluster, or jocularity. Take the exam seriously, but not paralyzingly seriously.

Chapter 5 – What Will I Be Asked in This Exam?

Understand the limited range and scope of questions that are possible. Although broad, most questions can be handled given realistic preparation. Practice the art of admitting “I don’t know” so as to not derail your whole exam. Advance selection of key illustrations for thesis-relevant points is a wonderful tool you are likely to use. Understanding your committee’s reactions to your success and failure on questions is valuable for maintaining your performance too.

Choreography of an Oral Exam

Understand in advance the respective roles of committee members in your particular institution’s exam setting, including the external examiner, committee chair, internal members, and your major supervisor. Know the order of the exam which may include a pre-exam seminar, public questioning, in-camera questioning. It is good to know the order of examiners, the first- and second-round dynamics, and your privileges for breaks and sometimes the final word. Understanding committee deliberations and possible outcomes is reassuring too.

Chapter 15 – Outcomes and Options for Moving Forward

There are very few outright oral exam fails. However, if your outcome is less than a pass with honors, you must be prepared to accept it constructively and try to convert it to the highest pass possible through extra work, changes to the thesis, and possibly a re-test. In the event of a fail, you still have options to consider but must do so in a rational, careful way. Vindication or face-saving are rarely adequate motivations to improve an outcome. Recognize and rely on your support network.