Search

Indoor spaces have become increasingly prevalent in human lives. While scholarship in other fields has studied the relationship between humans and the indoors, it has not been readily investigated in Geography. This study draws from prior research in Building Design, Managerial Science, and Education to examine the relationship between building users and resources in indoor spaces. To better understand how users seek resources in an indoor, academic space, this research asks: (1) what spaces and resources do building users value?; and (2) how are their perceptions of value associated with observed measures of occupancy? This research takes place in Goodwin Hall, on the Blacksburg campus of Virginia Polytechnic Institute and State University. This research relies on surveys conducted in 2018 as well accelerometer data collected in 2018 to examine the relationship between users' perception and use of resources in informal learning environments. Through quantitative analysis this research tests the ideal free distribution hypothesis. Findings indicate that certain measures of use and value support the ideal free distribution hypothesis. These results help to lay a groundwork for future geographic research in indoor spaces.

We investigate whether a dispersal strategy resulting in ideal free distribution (“IFD strategy”) is convergent stable. Species compete using fixed dispersal strategies in a patchy habitat with spatially varying but temporally constant carrying capacities. Population growth in each patch is governed by a function which is assumed only to be monotone decreasing and differentiable. For two-patch habitat, we give a complete description of outcomes when any two strategies compete. We show that there is selection toward IFD strategy, but such a strategy is not convergent stable because selection may be disrupted by emergence of a joint IFD between two species. We show also that IFD strategy is not convergent stable in an n-patch habitat. We derive some extensions of the model to allow for species-specific carrying capacities and analyze those extensions in the context of unconditional dispersal in a two-patch habitat. We present some numerical results for the case of time-periodic carrying capacities.

Understanding how patterns of habitat use by animals vary in relation to population density is of major interest to ecologists and wildlife managers. For decades, biologists have linked high populations of ruffed grouse (Bonasa umbellus) with aspen (Populus spp.) forests in the northern part of their range. However, male ruffed grouse in northern populations also select territories in conifer forests, even when apparently suitable aspen forests nearby remain vacant. This selection of cover types that are presumed to be of lower quality presents a conundrum to biologists: why would males select inferior cover types when better cover types are available? To address this conundrum, I investigated the behavior, habitat, and population dynamics of a population of male ruffed grouse to evaluate relationships among these factors and elucidate mechanisms of their cover type selections. Little is known about the mechanisms underlying habitat selection in most species. Studying the behavior of individuals within a population is one technique used to evaluate these mechanisms. Ruffed grouse are an ideal species in which to study behavior, habitat, and population dynamics because the males are easily counted, they are territorial, their territories are relatively easy to locate, and many populations are cyclic. I conducted my study at the Cloquet Forestry Center in northern Minnesota and used data collected over the course of one complete 10-year ruffed grouse population cycle (2002-2011) during which time the population reached both a high and low point in the numbers of territorial males counted each year. The grouse population was declining when the study begin in 2002 and did not begin its cyclic increase until 2006. I used repeated auditory surveys to locate the territories of drumming males and estimate the population density of territorial male grouse. I assessed behavior questions by using automated video systems to record the activities of a stratified (by aspen and conifer cover types) random sample of 23 male ruffed grouse from all of the males detected on my surveys. The number of breeding males on my 1,419-ha study area varied from a low of 47 in 2005 to a high of 134 in 2010. I assumed that rates of male ruffed grouse display were indicative of their interactions with conspecifics. I developed a priori models that described the relationships among male display rates and environmental attributes, structured these models as generalized linear models, and used information theoretic model selection to evaluate these models. The null model (i.e., intercept only model) was the top-ranked model (received the lowest AICc score). I used generalized linear models with random effects and information theoretic model selection to evaluate a priori models that described relationships among male ruffed grouse densities per cover type and environmental variables associated with their territory locations. Aspen-dominated cover types contained the highest densities of male ruffed grouse during all years (0.09 to 0.24 males/ha during 2002-11) except 2006 and 2011, when density was highest in northern hardwoods-dominated cover types (0.12 and 0.13 males/ha in 2006 and 2011, respectively) followed by aspen-dominated cover types (0.10 and 0.12 males/ha in 2006 and 2011, respectively). The density of males in conifer-dominated cover types was always less than the density of males in aspen-dominated cover types (0.02 to 0.08 males/ha during 2002-11). In addition to consistently higher densities of males in aspen- versus conifer-dominated cover types, densities of males in aspen-dominated cover types exhibited a higher intrinsic rate of increase than in conifer-dominated cover types during all years. However, the consistent occupancy of conifer-dominated cover types by males throughout the study also suggested that males perceived conifer-dominated cover types as suitable sites for territories and display behavior. At the cover type scale, the top-ranked model related to male grouse population density included an interaction of cover type and year variables. The mean density of male ruffed grouse within landscapes during all years ranged from 0.04 to 0.10 males/ha with minimum and maximum densities of 0 and 0.16 males/ha, respectively, during the entire study. At this landscape scale, an interaction of the estimate of the relative evenness of cover types (Shannon's Evenness Index) within landscapes and year comprised the top-ranked model explaining male ruffed grouse densities. Based on my study, if there is a difference in quality of conifer and aspen cover types, it manifests itself either in the specific stand structure used for male breeding displays or some life stage or seasonal habitat need of the ruffed grouse other than male breeding display cover. My results show that grouse populations achieve their highest densities in heterogeneous landscapes when aspen-dominated cover types, composed of multiple age classes, are the key cover types on landscapes. Landscapes that are less heterogeneous and where the majority of cover types are not dominated by aspen also harbor grouse, but at lower densities than heterogeneous aspen-dominated landscapes. Traditionally, managers have focused on the distribution and abundance of aspen-dominated cover types to enhance ruffed grouse habitat. However, my findings suggest that managers should focus on managing the spatial complexity of cover types on landscapes, even when aspen-dominated stands are in low abundance.

Pollinator responses to varying floral density have important implications for plant population dynamics, conservation, and the evolution of floral traits. Floral density can influence both flower visitation rates and the species composition of flower visitors, but neither of these effects is well understood. In my dissertation, I generate and test hypotheses explaining the relations of flower visitation rate and flower visitor species composition to floral density.In the first chapter, I present a foraging model that explores potential sources of variation in the effects of floral density on flower visitation rates. The model predicts that the relation of per-flower visitation rates to floral density will be nonlinear, with strong positive effects at low floral densities and weaker or negative effects at higher densities. Results from a field experiment using the annual composite Holocarpha virgata support this prediction. The model also shows that floral density in the surrounding environment and traits of both plants and their pollinators can influence the effects of floral density on visitation. In the second chapter, I describe an observational field study, again using H. virgata, that shows that flower visitors respond differently to floral density at site (12.6 ha) and patch (4 m2) scales and furthermore that floral density at the site scale influences flower visitors' responses to patch-scale floral density. This study also reveals an effect of floral density on the species composition of H. virgata's flower visitors. In the final chapter, I explore effects of floral density on the species composition of flower visitors, using a variation of the model presented in the first chapter. The model identifies several flower visitor traits, including flower search speed, flower handling time, and foraging currency, that can influence whether a species uses primarily dense or sparse patches when in competition with other species. Collectively, these studies fill a significant gap in our knowledge of pollinator responses to floral densities. By developing testable hypotheses based on biologically reasonable assumptions to explain many previously-observed phenomena, they lay the groundwork for understanding this important aspect of plant-pollinator mutualisms.

We utilize reaction-diffusion-advection equations in an adaptive dynamic frameworkto study the evolution of dispersal of two competing species. The species areassumed to be identical except for their dispersal strategies which consist of randommovement (diffusion) and biased movement (advection) upward along resource gradients.We focus on how spatial heterogeneity in the habitat influences selection. A key facet of this relationship is that diffusion creates a mismatch between a species population density at steady state and the resource function [9]. This led Cantrell et al. [9] to introduce a conditional strategy which can perfectly match the resource, resulting in the ideal free distribution of the species at equilibrium.This ideal free strategy (IFS) serves as a basis for our study. Not only do we showthat it is a global evolutionarily stable strategy, but we find conditions under which itis convergent stable, varying random dispersal rates, advection rates, or both of theseparameters at the same time. For two similar strategies on the "same side" of theIFS we show that when resource function is monotone, the strategy which is closerto the IFS is generally selected. For nonmonotone resource functions, we find thatthere may exist nonideal free strategies which are locally evolutionarily stable and/orconvergent stable [21]. In addition, we find that for certain nonmonotone resourcefunctions, two similarly competing species can coexist, which enables us to also showhow three species coexistence is possible.

The North American Waterfowl Management Plan (NAWMP) is built on the premise that the collective effects of regionally-delivered habitat conservation actions will impact waterfowl population growth by influencing survival and recruitment. Availability of food energy was identified as the factor most likely to limit vital rates of ducks during non-breeding periods. Daily ration bioenergetics models based on Ideal Free Distribution (IFD) theory are used to estimate quantitative habitat objectives for target duck populations. These models incorporate assumptions about daily energy demands of waterfowl, energetic carrying capacity of priority habitats, and the manner in which ducks use foraging habitats of varying energy density. The accuracy of these assumptions affects the degree to which habitat objectives are sufficient to support duck populations and contribute to achievement of NAWMP goals.I measured energetic carrying capacity (ECC), duck use, and wetland- and landscape-scale variables associated with actively and passively managed wetlands in central and northwest Ohio during autumn and spring, 2001-2004, to test assumptions of a bioenergetics model used by the Upper Mississippi River and Great Lakes Region Joint Venture (UMR & GLR JV). Mean ECC was statistically similar between actively and passively managed wetlands (actively managed = 3,446 duck energy-days [DED]/ha; passively managed = 2,047 DED/ha), and exceeded the UMR & GLR JV assumption that 1,236 DED/ha are provided by managed wetland habitats. However, ECC of actively and passively managed wetlands declined by >80% between autumn and spring migration, resulting in low food energy densities during spring (mean = 66 – 242 DED/ha).The probability of a wetland being used by ducks and cumulative duck use of wetlands were significantly and positively affected by food energy density. However, ducks did not use wetlands in direct proportion to food energy density, which contradicted predictions of daily ration models (DRM) and IFD theory. For example, parameter coefficients from one analysis suggested that for every doubling of ECC, cumulative duck use increased by only 33% during autumn and 13% during spring. Factors other than food energy density affected wetland use by ducks. Based on a subsample of 68 passively managed wetlands, duck use during autumn increased with ECC, wetland area, and area of wetlands within 1 km, but decreased as wetlands became increasingly isolated from other wetlands. Duck use during spring increased with ECC, decreased with increasing distance from rivers, but was unrelated to wetland area.Although DRMs provide a simplistic and useful method for calculating habitat objectives for wintering and migrating ducks, they likely do not accurately describe the complexity of factors affecting duck use of foraging habitats. My results suggest habitat objectives based on linear predictions of DRMs may underestimate habitat requirements of target duck populations. Lacking bioenergetics models that accurately describe functional carrying capacity of foraging habitats, conservation planners should consider providing habitat in excess of DRM predictions to ensure populations are not limited by undetected constraints on food availability.