Native plant materials are often seeded to restore biodiversity and ecosystem function in areas overtaken by exotic weeds. Plant materials are evaluated on intraspecific differences in productivity and expression of traits advantageous to establishment (e.g., phenology, seed mass, and growth rate); some investigations also consider population-level adaptation to exotic species. However, there is a lack of studies that broadly evaluate response to competition from exotic species at multiple scales within a species. In a greenhouse experiment, we used analysis of variance to assess the growth response of a perennial grass native to the Intermountain West, (Elymus elymoides), to competition from a common invasive species, (Bromus tectorum), at three levels of intraspecific differentiation: subspecies, lineage (wild vs. domestic germplasm), and population. We used regression analysis to assess whether E. elymoides populations from highly invaded areas were less affected by B. tectorum competition. Finally, we explored the relationship between growth traits and competitive response using random forest regression. We found significant differences among E. elymoides subspecies in their response to B. tectorum competition, no difference between wild and domestic lineages, and no population-level differentiation within subspecies. Field abundance of B. tectorum had a significant positive relationship with E. elymoides biomass, but not competitive response, suggesting that E. elymoides has not adapted to the invader. Elymus elymoides plants which were less affected by competition were smaller, allocated more biomass to leaves, and had fewer fine roots, suggesting that light interception and tissue retention were prioritized by seedlings in this competitive greenhouse environment.

The American marten (Martes americana) is an endangered species in Vermont and a Regional Species of Greatest Conservation Need in the northeastern United States. Though historically widespread in northeastern forests, their range presumably contracted to northern Maine and the High Peaks region of the Adirondacks by the early 1900s. Regionally, populations appear to be in recovery. Natural recolonization is believed to have occurred in New Hampshire, northeastern Vermont and the western Adirondacks. A reintroduction effort in southern Vermont that was originally declared unsuccessful is now believed to be the source of a recently detected population in the area. However, our current knowledge of distribution, population history and population connectivity relies primarily on occurrence data from harvest records, which are limited in scope and resolution. In Vermont, where population size is estimated to be extremely low, more robust estimates of population status may be critical to continued recovery. I genotyped individuals from Maine, New York, New Hampshire, northeastern Vermont and southern Vermont at ten microsatellite loci and amplified a 320 base pair segment of the control region of mtDNA to estimate the source(s) of the two Vermont populations using statistical tests of genetic differentiation. I also used Bayesian and stochastic genetic clustering methods to estimate population genetic structure in the northeastern United States. Genetic structure exists at multiple scales in the region as a result of natural barriers to gene flow, human-mediated gene flow, and lineage sorting in relic populations. My results suggest that New Hampshire is a major source of colonization of northeastern Vermont and the population in southern Vermont is either a remnant of the reintroduction or a pre-reintroduction relic that has experienced introgression from the reintroduction stock. I identified three regions where relic populations perceived to be extirpated in the 1900s may have persisted. I also developed an occupancy model for American marten in the northeastern United States using mixed-effects logistic regression based on expert opinion data. Eighteen experts from Maine, New Hampshire, Vermont and New York with backgrounds in trapping, wildlife management, and wildlife science participated in the survey. Experts were asked to estimate the probability of marten occupancy at 30 sites in the northeastern United States. Three top models described the data. Habitat covariates in those models were 1) percent canopy cover, 2) percent spruce-fir forest cover, 3) winter temperature, 4) elevation, and 5) road density. An AIC-weighted average of these three models had significant predictive ability (area under an ROC curve = 0.88) with respect to occurrence records in the northeastern United States. In addition, the model predicted that high quality habitat existed patchily along the central and northern Green Mountain spine in Vermont – where no occurrence records exist for at least a century. Top-scoring movement corridors between southern Vermont and nearby populations in northeastern Vermont/New Hampshire and New York occurred in the northern and central Green Mountains and across high resistance movement barriers in the Champlain valley. Corridors to New York were considered strong movement barriers and are unlikely to facilitate gene flow.

The Donlin and Pebbles mines are two of the eight industrial-scale hard rock mines currently under the review of Alaska’s Large Mine Permitting program. Both projects promise to deliver profit and employment to their respective regions: Pebble to Bristol Bay in the southwest, and Donlin to the Yukon-Kuskokwim Delta, just north of Pebble. Both projects would also produce exceptional quantities of waste and will require almost-unprecedented infrastructure development, potentially threatening the lives and subsistence livelihoods of the Alaska Native peoples in their respective regions. The Pebble project inspired international protest and led to the emergence of a powerful resistance coalition of commercial, recreational, and subsistence fishers; activists and expert-consultants were thus able to build a powerful movement outside of and prior to the state permitting and impact assessment process. The coalitions that arose to oppose the Donlin project, in contrast, channeled their work through the state’s official public engagement processes – in part, due to strategic limitations stemming from the complexities of land use, sovereignty, and development politics specific to the Yukon-Kuskokwim region. The coalitional resistance to Pebble and the creative use of Donlin’s public participation process are key sites in which Western science and knowledge systems, as well as land use ideologies centered on extraction and profit, meet with Native Alaskan traditional knowledge and subsistence approaches to land use. I draw upon a history of Alaskan land use policy alongside extensive interviews with community organizers, state and federal officials, mining industry officials, and consultants in order to describe and understand the result: a set of creative resistance strategies that forefront hybrid approaches to knowledge and multiple, overlapping understandings of the land. Unfortunately, Alaska’s large mine permitting and environmental assessment processes are often structurally and epistemologically unable to consider these divergent discourses and the public imaginations of alternative futures they support and constitute.

Mass animal migrations represent large movements of biomass, energy, and nutrients with predictable patterns and important ecosystem-level consequences. Diel vertical migration (DVM) in aquatic systems, the daily movement of organisms from deeper depths during the day to shallower depths in the water column at night, is widespread in freshwater and marine systems. Recent studies, however, suggest partial migration behavior, whereby only some portion of a population migrates, is the rule rather than the exception in a range of migratory fauna, including those that undergo DVM. Hypotheses to explain why partial migrations occur complicate traditional views on DVM and challenge conventional theories. I address intraspecific variation in DVM behavior of an aquatic omnivore, Mysis diluviana, to test several long-standing assumptions about benthic-pelagic DVM in Mysis. I evaluated the extent of partial DVM and several potential drivers within a Lake Champlain Mysis population. I used traditional net-based field observations, a novel deep-water video camera system, and a laboratory experiment, to compare distributions, demographics, abundance estimates, hunger-satiation state, and feeding behavior, of migrant and non-migrant Mysis across multiple seasons, habitats, and different times of the day. Findings from my dissertation suggest Mysis partial DVM is common, and is associated with body size and demographic differences among individuals. Partial DVM behavior, however, did not correspond to strong differences in feeding preference or hunger-satiation state of individuals. My results contribute toward a more comprehensive understanding of migration theory and mysid biology, by including the often overlooked, but important, benthic habitat component of DVM studies, and fills in several ecological knowledge gaps regarding a key omnivore in many deep lake food webs across North America where Mysis serve as both predators and prey to many organisms.

Understanding what promotes invasiveness of species outside their native range and predicting which ecosystems and under which conditions will be invaded is an ultimate goal of the field of invasion ecology. Obtaining general answers to these questions requires synthesis of extensive yet heterogeneous empirical evidence, coupled with a solid theoretical background. In this dissertation, I sought to provide insight into the drivers of non-native plant invasions through combining and synthesizing ecological data from various sources using advanced statistical techniques. The results of this work are presented as three independent research studies. In the first study, I aimed to understand what determines competitive advantage of non-native over native plants: the ability to suppress other plants, tolerate them, or both. For this, I collected data from 192 studies on plant competition and analyzed them within a Bayesian multilevel meta-analytic framework. I showed that non-native plants outperform their native counterparts due to the high tolerance of competition, as opposed to strong suppressive ability. Competitive tolerance ability of non-native plants was driven by neighbor’s origin and was expressed in response to native species and not to other non-native species. This synthesis demonstrates that non-native plants are competitively distinct from native plants and challenges the common notion that neighbor suppression is the primary strategy for plant invasion success. In the second study, I quantified the extent to which regional, landscape and local environmental factors individually and jointly affect understory non-native invasive plants across northern US forests. I used boosted regression trees and Bayesian nonlinear regressions to analyze forest inventory data spanning 14 northern US states in combination with data on climate, land use, and disturbance. Regionally, the highest level of plant invasion was observed in hotter regions with lower annual precipitation and climate seasonality and higher summer precipitation. Locally, young forests with moist to wet soils and relatively flat topography in open, human-altered landscapes at low elevation were most susceptible to invasion. Climate and land use strongly interacted in their effect on plant invasions. This study refines the understanding of the non-native plant invasion process in northern US forests and the obtained models can be used to generate predictions under current and future environmental regimes to inform management. In the third study, I tested the relationship between the long-term history of recurrent canopy disturbance by a non-native invasive defoliator, the gypsy moth (Lymantria dispar), and the level of non-native plant invasion in northeastern US forests. I reconstructed 46 years (1970–2015) of gypsy-moth defoliation history and quantified the cumulative effect of defoliation on understory non-native invasive plant species using multivariate techniques and Bayesian nonlinear regressions. Contrary to what is commonly expected, the cumulative severity of gypsy moth defoliation tended to be negatively associated with the presence and richness of invasive plant species, although this association was weak. This study suggests that the effect of biotic disturbance on forest plant invasions may vary in both the magnitude and direction depending on characteristics of disturbance regime and its effect on resident biota, and this needs to be explicitly taken into account when predicting future plant invasions.

Few empirical studies exist that compare regulation (R) and fishing crime (VL). The lack of information about R and VL effects stakeholder decision-making. Crime weakens conservation efforts and creates false baseline data. This furthers R and the cycle repeats. The purpose of this correlational study was to determine the statistical association between the number and type of annual commercial blue crab R and VL of the same. The Pearson's R correlation was used to analyze the data because it demonstrated the strength of each relationship. This quantitative study was grounded in enforcement theory. The data was public record and consisted of the number of R and VL issued yearly from the General Assembly of a Mid Atlantic's State Department of Natural Resources (MD-DNR). The intent was to correlate multiple decades, but the earliest available VL data began in 2009. The analysis uncovered divergent patterns. The correlation coefficient of 0.79644 confirmed laws from 2009 correlated positively with 2010 violations. Further analysis revealed a negative correlation for 2010 and 2011 that was indicated by a negative correlation coefficient of -0.3588 and -0.166. The mean average of VL was 12.5%. As restrictions keep increasing, the economic impact on local communities is substantial. This research has the potential to effect positive changes in restrictive harvest practices, record keeping of VL by Natural Resources of this Mid Atlantic State, and harvest reporting practices by crabbers. Sharing the findings with industry stakeholders may stimulate dialogue among stakeholders that answers why one type of regulation was violated more than another, encourage compliance by industry users, and improve conservation efforts to proliferate blue crab. This research contributes to future investigation of often-neglected variables that compromise conservation of blue crab.

Medusahead is a harmful weed that is invading public lands in the West. The invasion is a serious concern to the public because it can reduce forage for livestock and wildlife, increase fire frequency, alter important ecosystem cycles (like water), reduce recreational activities, and produce landscapes that are aesthetically unpleasing. Invasions can drive up costs that generally require taxpayer’s dollars. Medusahead seedlings typically spread to new areas by attaching itself to passing objects (e.g. vehicles, animals, clothing) where it can quickly begin to affect plants communities. To be effective, management plans need to be sustainable, informed, and considerate to invasion levels across large landscapes. Ecological remote sensing analysis is a method that uses airborne imagery, taken from drones, aircrafts, or satellites, to gather information about ecological systems. This Thesis strived to use remote sensing techniques to identify medusahead in the landscape and its changes through time. This was done for an extensive area of rangelands in the Channel Scabland region of eastern ashington. This Thesis provided results that would benefit land managers that include: 1) a dispersal map of medusahead, 2) a time line of medusahead cover through time, 3) “high risk’ dispersal areas, 4) climatic factors showing an influence on the time line of medusahead, 5) a strategy map that can be utilized by land managers to direct management needs. This Thesis shows how remote sensing applications can be used to detect medusahead in the landscape and understand its invasiveness through time. This information can help create sustainable and effective management plans so land managers can continue to protect and improve western public lands threatened by the invasion of medusahead.

Watersheds are often managed without direct knowledge of how salmonid species use spatially-distinct spawning habitats within their watersheds, and rarely take into account the relationship between fish movement and potential population structure when making management decisions. The population of native Bonneville cutthroat trout (Oncorhynchus clarki utah) within the Logan River is the largest documented population remaining for this imperiled species, and still maintains extremely high densities of native fish in the upper river. Currently, fishing is not allowed in the upper 20 kilometers of the Logan River watershed during spawning, based on the assumption that cutthroat trout migrate to and spawn primarily in this section. I redetected cutthroat trout tagged (2,271) during years 2008-2012 in seven mainstem and tributary reaches of the Logan River during spawning months (April-June) of 2013 using a combination of stationary detection systems and mobile scanning techniques. Cutthroat trout in both mainstem and tributary reaches exhibit a leptokurtic movement distribution, indicating most fish spawn near to their original tagging site; however, small percentages of trout moved long distances to seek out spawning sites throughout the watershed. Growth, length, and condition estimates between mobile and non-mobile tagged fish demonstrate that while mobile fish tend to growth faster, be slightly larger, and in some cases be in relatively poorer condition, these differences are often biologically insignificant and dependent on site location within the watershed. A genetic microsatellite DNA analysis conducted on trout sampled from each study site confirms the assumption of panmixia, and I observed very little evidence of sub-population structure. Using River Styles® to assess geomorphically distinct reaches, I created a large-scale population estimate of spawning individuals, which found approximately 61% of spawning cutthroat trout are not subject to angling during the spawning season, while 39% could be susceptible to harvest in the lower basin and its tributaries. Most trout within the Logan River likely spawned very close to initial tagging locations and microsatellite analyses confirmed the population is genetically well-mixed, indicating conservation efforts should promote risk-averse management throughout the watershed, rather than focus heavily on any one section of the river.

Connectivity is a major contributor to the overall dynamics of marine populations. However, it still remains challenging to describe connectivity on ecologically meaningful scales of time and space. This is a major impediment to evaluating the impacts of marine protected area with respect to fisheries management objectives. This dissertation brings together a wide array of spatial and connectivity information in the Gulf of Mexico (GOM) with the goal of 1) understanding the spatial distribution of fish populations and source-sink dynamics and 2) evaluating whether this information can be integrated, through a modeling framework, to identify closed areas that could be beneficial to fisheries management in the Gulf of Mexico. First, a generalized additive modelling (GAM) approach is used to describe the distribution of a large number of species groups (i.e. functional groups) across the Gulf of Mexico (GOM) using a large fisheries independent data set (SEAMAP) and climate scale (decades) oceanographic conditions. Next a numerical Lagrangian particle transport model was developed that incorporates two major connectivity processes; site specific larval production and oceanographic transport for an entire large marine ecosystem and over multiple years. The two components are then combined to develop larval dispersal patterns for the entire GOM and identify areas operating as larval sources and sinks. Last, this information is integrated into an end-to-end ecosystem model to evaluate effectiveness of closing source and sink areas for the management of reef fish fisheries. Closed area managemeny simlautions for reef fish indicated closing reef fish source areas, as opposed to sinks, in the GOM is most efficient method of increasing total biomass and yield. However, the impacts across individual functional groups were site specific. Ultimately, these simulations demonstrate the inclusion of connectivity information could improve fishery management objectives in an ecosystem context.

No description available.