Browsing by Author "Simanonok, Michael Peter"
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Item Interaction turnover among pollination networks across space, time, and environment(Montana State University - Bozeman, College of Letters & Science, 2013) Simanonok, Michael Peter; Chairperson, Graduate Committee: Laura BurklePollination networks provide an ideal system in which to test hypotheses around interaction turnover across ecologically meaningful gradients, as there is already baseline understanding of plant and pollinator communities. Parallel declines in plants and pollinators imply that disruption of interactions between species in pollination networks may be leading to pollinator declines; therefore, beginning to understand how plant-pollinator interactions turnover through space, time, and environment could be vital for future conservation and management efforts. I investigated i.) how do plant and pollinator species diversity (i.e., richness and evenness), phenology, and composition change across space, time, and environment, ii.) how do interactions between pollination networks turn over across these same gradients (i.e., space, time, and environment), and iii.) what is the relative contribution of species turnover (plant, pollinator, or both simultaneously) vs. host switching to interaction turnover among pollination networks? Field work was conducted during summer 2012 on the Beartooth Plateau, an alpine ecosystem in Montana and Wyoming, with weekly observations of plant-pollinator interactions and the floral community across the growing season. Community diversity and composition were compared across space, time, elevation, slope, and aspect using linear regressions, t-tests, and principle coordinate analysis. Interaction turnover was calculated between all possible pair wise combinations of study site and week and compared across, space, time, elevation, slope, and aspect using a partial Mantel test and linear regressions. We found that interaction turnover mostly occurred due to simultaneous species turnover of both plant and pollinator communities with host-switching having marginal contribution. Furthermore, interaction turnover occurred across temporal and environmental gradients, with no significant variation across spatial scales. These results differ greatly from inter-annual patterns on the contribution of species turnover vs. host switching, however some results may be due to sampling or scale limitations. It is possible that host switching does not readily occur within-season, but more work is needed for confirmation. Spatial and environmental patterns remain possible, but did not emerge at the extents used herein. This study represents the first instance of the partitioning of interaction turnover into individual species components for a pollination network, and the first to do so intra-annually.Item Partitioning interaction turnover among alpine pollination networks: spatial, temporal, and environmental patterns(2014-11) Simanonok, Michael Peter; Burkle, Laura A.Ecologists have taken two distinct approaches in studying the distribution and diversity of communities: a species-centric focus and an interaction-network based approach. A current frontier in community-level studies is the integration of these perspectives by investigating both simultaneously; one method for achieving this is evaluating the relative contributions of species turnover and host switching towards interaction turnover (i.e., the dissimilarity in interactions between two networks). We performed observations of plant-pollinator interactions to investigate (1) patterns in interaction turnover across spatial, temporal, and environmental gradients and (2) the relative contribution of pollinator species turnover, floral turnover, simultaneous pollinator & floral turnover, and host switching towards interaction turnover. Field work was conducted on the Beartooth Plateau, an alpine ecosystem in Montana and Wyoming, with weekly observations of plant-pollinator interactions across one growing season. Interaction turnover increased through time, with magnitudes consistently greater than 80%, even at time intervals as short as one week. Floral species turnover (41%) and simultaneous floral and pollinator species turnover (36%) accounted for almost all interaction turnover while host switching accounted for only 5%. Interaction turnover also significantly increased with spatial and elevational distance, albeit with lesser magnitudes than with temporal distance. The marginal spatial pattern was present for only some taxa (Bombus spp. and solitary bee species), potentially indicating variable habitat use by pollinators across the landscape. Weak environmental trends may be a consequence of unmeasured environmental variables, yet our finding that environmental gradients structure plant-pollinator interaction partitions had not previously been tested with empirical data. Our observations suggest that host switching does not readily occur at the scales of alpine flowering phenology (i.e., ∼1 week); however, whether lack of host switching is indicative of inflexible pollinator foraging, or, more likely, a lack of opportunity or necessity to switch hosts, requires further investigation.Item Plant-pollinator network assembly after wildfire(Montana State University - Bozeman, College of Letters & Science, 2018) Simanonok, Michael Peter; Chairperson, Graduate Committee: Laura BurklePlant-pollinator networks are threatened by anthropogenic influence due to habitat loss, changing fire regimes, climate change and other factors. Furthermore, we have little current knowledge for how species interactions and processes like pollination assemble and recover post-disturbance. Studying the mechanisms by which plant-pollinator interactions assemble in a post-disturbance landscape, particularly across gradients of disturbance intensity and successional time, would greatly help in building foundational ecological knowledge regarding the assembly of species interactions as well as provide specific information to aid conservation and management. Therefore, we investigated plant-pollinator network assembly after wildfire, between mixed- and high-severity burns and across time-since-burn, and we asked i) how do network structure and the network roles of persistent species vary ii) how does wildfire change the nutritional landscape of available floral pollen quality and how does that influence bumble bee foraging and nutrition, and iii) how do nesting and floral resources affected by wildfire influence wood-cavity-bee nesting success and richness? Our study design involved four wildfires from the Absaroka Mountains of southwest Montana, USA, which included a range of burn severities as well as a 1-25 year chronosequence of time-since-burn sampled primarily from 2014 to 2016. Bees were sampled via hand netting and nesting boxes alongside floral census transects and pollen sampling to assess metrics important to plant-pollinator network assembly, available floral pollen quality, bumble bee nutrition, and wood-cavity-nesting bee nesting success. The primary findings are that i) plant-pollinator network structure does not dramatically shift with burn severity or time-since-burn, nor do the network roles of persistent species, ii) available floral pollen quality and bumblebee nutrition are limited by high-severity burns, and iii) burn severity has little effect on the nesting success of wood-cavity-nesting bees. The conclusions that follow these results are mainly that i) evidence of constant structure and low variance of species' roles provides evidence for preferential attachment over opportunistic attachment in assembling plant-pollinator networks post-disturbance, ii) varied species composition between mixed- and high-severity burns may mean that bumble bees are nutritionally limited in high-severity burns, and iii) nesting resources do not appear to strongly limit nesting success or richness of wood-cavity-nesting bees.