Firefighting is a strenuous occupation that requires high-intensity work, resulting in prolonged periods of stress and physical exertion. The physical demand of performing firefighting tasks is augmented by the weight of personal protective equipment (PPE) worn (i.e., load carriage: LC) and the use of a self-contained breathing apparatus (SCBA). These factors have been shown to increase metabolic demand at submaximal workloads and decrease maximal aerobic capacity in laboratory settings. However, there is limited research evaluating the effects of these factors on occupational performance. Therefore, the primary purpose of this study was to quantify the detrimental effect of LC only and LC+SCBA on firefighter occupational performance. In addition, it is important to identify fitness characteristics and physiological outcomes that are correlated to the decrement in performance produced by the PPE. This information will guide practitioners in selecting appropriate training strategies to effectively prepare firefighters to perform occupational tasks in gear. Thus, a secondary aim was to evaluate the relationships between fitness and pulmonary outcomes versus the decrement in occupational performance produced by the PPE. Twenty-one male firefighter recruits (Age: 28.6 ± 4.3 yr; Height: 178.6 ± 7.2 cm; Mass: 94.1 ± 15.4; Body Fat: 17.8 ± 8.4%) participated in this study. Occupational physical ability was assessed by time to complete a simulated fire ground test (SFGT). The SFGT was composed of the following tasks: stair climb, charged hose drag, equipment carry, ladder raise, forcible entry, search, and victim rescue. The recruits participated in six testing sessions. First, two SFGT familiarization trials were performed on separate days. During the next three testing sessions, the firefighter recruits performed the following SFGT conditions in a randomized order: control condition (PT clothes), LC only condition, and PPE+SCBA (SCBA) condition. Baseline and post-SFGT pulmonary and physiological data were collected. To describe within group differences between SFGT conditions, relative difference scores were calculated as follows: % difference = (([experimental trial outcome – PT trial outcome] / PT trial outcome) x 100). Statistical differences between the SFGT conditions were assessed with repeated measures ANOVA. To evaluate the relationship between fitness outcomes versus the decrement in SFGT performance, fitness testing data were obtained from the recruit academy and included: 1.5 mile run time, maximal push-ups, maximal sit-ups, maximal pull-ups, and prone plank time. In addition, the recruits completed a battery of fitness tests in their sixth testing session. The absolute difference in time to complete the SFGT between conditions was calculated as: experimental SFGT time - PT time. Bivariate correlations were used to assess the relationship between the absolute difference in SFGT time versus fitness outcomes. The LC+SCBA trial took 44.5 ± 15.5% longer (345.9 ± 43.7 s; p < .001) and the LC only trial took 38.3 ± 12.6% longer (331.2 ± 39.3 s; p < .001) to complete the SFGT than the PT trial (241.0 ± 33.3 s). The LC+SCBA trial took longer to complete the SFGT than the LC only trial (p = .046). Post-SFGT RPE was higher in the LC+SCBA trial (6.7 ± 1.7) and LC only trial (6.3 ± 1.5) compared to the PT trial (4.6 ± 1.8; p < .001). Absolute aerobic capacity, lower body power, anaerobic power and capacity, abdominal muscular endurance, and upper body strength were significantly correlated to the decrement in SFGT performance on some tasks caused by the PPE. In summary, PPE increases the intensity of performing fire ground tasks. To enhance occupational performance, it is imperative that firefighters optimize specific physical fitness attributes to reduce the relative stress produced by the PPE.

The myriad ways species interact with each other have always captivated biologists. These interactions—predation, competition, parasitism, and mutualism—are fundamental to the stability of ecological communities and drive the evolution of species they contain. Some mutualistic systems consist of mutually dependent partners that strongly influence each other’s survival, while other mutualistic systems consist of many, diffuse relationships between large assemblages of partners. Critical ecological processes like pollination and seed dispersal are prime examples of such complex systems. Plant-pollinator communities are characterized by extensive pollinator sharing among plant species. My dissertation explores some of the consequences of this reliance on shared pollinators on the structure of plant-pollinator interaction networks, the foraging decisions of pollinators, and the fitness outcomes of plant species. Through several comprehensive field studies, I contribute to our understanding of mutualist interaction patterns at multiple levels of biological hierarchy: the community, species, and individuals. My first chapter examines the forces driving the change in interaction patterns of an entire plant-pollinator community and individual species throughout the flowering season. Nearly all studies of plant-pollinator interaction networks ignore potential intra-annual variation, and in doing so may be missing critical mechanisms contributing to overall community stability. I find that the overall turnover of interactions is high and driven by a process of interaction rewiring in which species frequently shuffle between available partners. Furthermore, I distinguish pollinator species whose interactions are driven by an abundance-based neutral process versus those that change their interactions beyond what is predicted by a neutral, abundance-driven null model. My second chapter uses a network-based framework to consider the fitness consequences for plants participating in a diffuse plant-pollinator network. I analyze the relationship between plant species’ network metrics and pollen deposition. Empirical examples that link patterns of interactions and functional outcomes (e.g., pollination) are scarce, but necessary to establish the utility of characterizing species interaction patterns. My final chapter explores how pollinator composition, local floral neighborhoods, and timing of flowering influence the pollination outcomes of individual Oenothera fruticosa flowers. I demonstrate extensive intraspecific variation in receipt of pollen from other species (‘heterospecific pollen receipt’) and find that this heterospecific pollen has a negative fitness effect if present in sufficiently high amounts. Together, the chapters of my thesis provide novel insights into the consequences of pollinator sharing among co-flowering plant species. / Biology