Human induced global change has greatly contributed to species loss with profound consequences for humans and other organisms. With the rapid pace of climate change and the slow adoption of sustainable actions, I argue that art-science integrated research can enhance our understanding of interspecies connections and support the development of sustainable societies. Working with iconic Joshua trees as a symbol of the nature/culture interface, I take an ecological, eco-art, and multispecies studies approach to understand the ways that climate change impacts the important symbiotic interactions that regulate Joshua tree distribution and how art can provide a meaningful connection to that work. First, I characterize and quantify populations of Joshua trees and their key symbionts – moth pollinators and mycorrhizal fungi – across a climate gradient in Joshua Tree National Park, to understand how their context-dependent associations change with climate and the resulting implications for tree survival. I found that moth number, trees number, and all measures of tree vigor peaked around the same elevation, but that the moths were not present at Joshua tree range extremes even though the trees were flowering at those locations. I also found that the reproductive success of Joshua trees is tightly linked to pollinator abundance, and the conditional outcomes (magnitude of the fitness benefit) of the mutualism change depending on where it occurs on the elevation gradient. Likewise, we found that fungal communities change with elevation, and that different fungal communities resulted in a spectrum of interaction outcomes from mutualism to parasitism that depended on the developmental stage of the plant. These are important examples of how climate change can impact species distributions directly (acting on either the moth, the fungi, or the Joshua tree) as well as indirectly by affecting the interactions between them. Next, I discuss my research findings in relation to the California Desert Protection and Recreation Act, highlighting areas where the Act falls short on Joshua tree protection and recommending future research and policy considerations. Finally, I discuss how those ecological findings, when colored by Donna Haraway’s multispecies studies approach, influence my multimedia social-practice art work Staying with the Trouble for Joshua Trees. My art practice engages diverse communities in the experience and discourse of species loss in three media: an experimental and conceptual painted soil study, a stop motion animation, and a mock online dating site to meet Joshua trees. Through this work I discuss how art can be a powerful tool for social change, both as an inquiry-based practice and a platform to share complex environmental issues with a diverse public.

As a drone pilot, ecologist, and scientist comfortable with emerging remote sensing technologies I have designed my dissertation around using drones to understand landscape processes and the ethical challenges associated with using drones as they intersect with privacy concerns. This work is organized into two main parts, with the first part exploring the role of plant pathogens in wildlands and the use of drones to enhance plant disease research. The second part examines the legal and ethical implications of commercial use of drone technology.

In the first half, I used drones to map the distribution of host plants in diverse wildland communities, contributing to a better understanding of plant diseases in two closely related wildland manzanita plant species. I employed advanced computer modeling techniques to accurately identify dominant plant species, crucial for conservation efforts in this challenging landscape. Additionally, I used analytical approaches to examine the relationship between the amount of time that leaves have wet surfaces and the association with the spatial distribution of plants along a coastal to inland climate gradient, providing valuable insights into diseasedynamics.

The second part of this work explores the ethical considerations of using drones and the importance of balancing the benefits of drone technology with minimizing harm to the environment, respecting privacy expectations, and ensuring transparency and equity. I analyzed the historical, legal, and policy aspects of drone use, focusing on federal safety regulations and state privacy laws. The tension between federal and state regulations underscores the need for drone pilots to be well-versed in both. Then, I examine the existing federal certification framework for drone pilots and identify the lack of training on privacy ethics and best practices for maintaining transparency. I propose expanding professional certification beyond the federal program to include a focus on privacy concerns. This certification, administered through non-profit organizations collaborating with commercial and higher-education entities, can help establish industry standards and provide essential training for drone pilots.

Overall, this dissertation demonstrates the significant potential of drones in ecological research, particularly in studying plant diseases and wildland conservation. And, highlights the importance of ethical considerations, privacy protection, and transparent practices in the use of drone technology for scientific purposes.

Combining quantitative and qualitative approaches, I examine the implementation of the Superfund Act on former US military bases, which represent the nation’s most hazardous waste sites. First, I used data from 127 military Superfund sites for a quantitative analysis of how technical (e.g., the severity of contamination), political (e.g., budgetary priorities), and socioeconomic (e.g., race and income) factors contribute to how quickly sites are remediated. I found that the most contaminated sites do get tackled first, contrary to criticisms of Superfund as an inefficient and overly bureaucratic program. Although socioeconomic factors such as race and income seemingly have little effect on the pace of military site cleanups, qualitative fieldwork shows that economically and ethnically marginalized communities can be particularly vulnerable to the residual effects of a history of militarism. My qualitative fieldwork in California and Puerto Rico examines how widely adopted federal policies on environmental justice and community participation influence site cleanups and finds that (1) Communities may suffer from disproportionately poor health status, yet it is outside the jurisdiction of Superfund to redress any lingering effects from historical exposures to military activities. (2) Public participation is low in part because there are no formal mechanisms to ensure agencies are responsive to public input. Furthermore, participation programs are similarly restricted in addressing health concerns or any social impacts related to past military activities. (3) A lack of historical data on military activities and small and mobile populations make it difficult to reconstruct past health exposures. Taken together, these issues confound the ability of the military to implement its own adopted environmental justice strategies and diversify public participation, as well as respond to the broader health, ecological, and social concerns of affected communities. I conclude with policy recommendations, including 1) the implementation of peer-reviewed evaluations of citizen advisory boards, 2) an increase in community capacity to participate in and influence cleanup programs, 3) better coordination of Superfund cleanup programs with existing government initiatives to assess and address disproportionate health impacts, and 4) the orientation of public health studies not at proving a causal relationship between poor health status and military toxins but rather at establishing what basic healthcare and health surveillance is needed at present.

Fungi shape the dynamics of natural ecosystems as pathogens, nutritional mutualists, and decomposers. They are also important as Special Forest Products with cultural and economic significance. I took an interdisciplinary approach to understand how fungal reproduction varies in response to abiotic (weather) and biotic (vegetation) factors, and how forest managers in the Pacific Northwest manage collaborative activities associated with Special Forest Products. I used three complementary approaches to examine temporal and spatial variation in reproduction in fungal communities. First, I measured the phenology of airborne fungal spores in coast redwood forests, mixed-evergreen forests, and maritime chaparral in coastal California, USA. Temporal patterns in meteorological factors (relative humidity, temperature) were more important in determining airborne fungal spore abundance than was vegetation type. This suggests that overall patterns of fungal reproductive dynamics may be predictable across heterogeneous landscapes based on local weather. Second, I used novel metagenomic techniques to identify unculturable and culturable airborne fungi across a vegetation mosaic. I found that the assemblages of fungal species vary strongly over time, with little spatial structure associated with habitat types. Third, for airborne spores collected from different vegetation types, I measured physical traits that may be important for survival, dispersal, or response to environmental change. I found larger and elongated spores in dry and structurally open vegetation (chaparral) compared to smaller and rounder spores in wet and structurally closed vegetation (forests). These results suggest that fungi in chaparral possess spore traits that allow them to persist and disperse in harsh, dry, open conditions. Finally, I examined the position of Special Forest Products like mushrooms and berries, in large-scale, collaborative planning for ecosystem-based management and the role of stakeholder participation to improve natural resource management. Working in the Pacific Northwest, I conducted a regional survey and interviews with national forest managers and found that collaborative activities occur at small scales (< 20 acres) and are driven by bi-lateral stakeholder interactions and legal obligations to stakeholders such as federally recognized Native American Tribes. These findings modify existing hypotheses on collaboration of natural resources and can aid national forests in future collaborative resource management.

Responding effectively to accidental introductions of plant pests (e.g., fungi, bacteria, viruses, animals, plants) is complicated because timely and costly decisions must be made across social and ecological scales with limited information. In this dissertation, I provide an interdisciplinary framework that allows responsible institutions to respond quickly and effectively to an emerging, introduced, multi-host pest-pathogen complex using even minimal knowledge available about pest attributes. First, I take an evolutionary ecology approach and examine how the phylogenetic structure of host ranges of different pest-pathogen combinations can be used to predict likelihoods of establishment, spread, and impacts of Fusarium dieback - invasive shot hole borers (FD–ISHB) in the urban-wildland forests and avocado growing regions of Southern California, where the pest-pathogen complex has established after its introduction from Southeast Asia. Phylogenetic dispersion analysis on a comprehensive FD–ISHB host-range data set shows that the strength of the phylogenetic signal is progressively more pronounced for more severely affected host species. As a basis for risk analysis, this understanding helps plant health first responders assess how any polyphagous pest complex might behave when introduced to novel environments with a new set of possible hosts, which in turn informs more efficient and cost-effective phytosanitary surveillance priorities. Second, I conduct a multivariate analysis of fungi and bacteria cultured from wood in a phylogenetically diverse set of live tree hosts to determine if the structure and composition of tree microbiomes is predictive of the likelihood or outcome of attack by FD–ISHB. I further explore interactions within the microbiome between endophytic microbes and the pathogen to identify potential opportunities and mechanisms to shape disease establishment and spread, and evaluate whether endogenous microbes could be manipulated for sustainable integrated pest management. I found consistent differences in wood-inhabiting microbial communities between avocado, which grows in an agricultural setting, and three wildland tree species (willow, sycamore, and oak), but there were no strong, consistent differences among microbial communities based on host attack status. However, enough differences were detected to suggest that inconsistencies most likely reflect undersampling in the community – a common problem with culture-based studies – which sets the stage for future culture-independent studies that integrate a richer data set into the analysis. Furthermore, 15 fungal species and 11 species of bacteria exhibited clear in vitro antagonism against the pathogen, indicating their potential to confer a protective benefit to tree hosts as biological control agents. Finally, I analyze participant-observation and public-document data to assess the effectiveness of governance processes that influence management decisions in a statewide deliberative and consensus-directed process to control FD–ISHB spread and impacts. I found that the comprehensive set of collaborative actions that emerged from this process were due to conditions identified in theoretical frameworks for collaborative governance and could not have been attained by any organization acting alone. These actions were enhanced by the structure and quality of principled-engagement process elements, which benefited from prior histories of cooperation and conflict. Collectively, this dissertation provides valuable technical and collaborative tools to improve integrated pest management and respond to the large-scale socio-ecological disturbances that accompany invasive, introduced pests.

The potential for tropical restoration legume and non-legume trees to suppress the invasive C4 grass Saccharum spontaneum in Panama

Justin A. Cummings

Saccharum spontaneum L. subsp. spontaneum is a large, exotic C4 grass species that invades abandoned agricultural fields in many tropical countries and can prevent natural forest regeneration. In Panama, studies on restoration of areas dominated by S. spontaneum have focused on identifying trees that establish readily after S. spontaneum removal. Few studies have evaluated how planted trees can suppress subsequent regeneration of S. spontaneum.

This dissertation focused on how legume and non-legume trees planted for restoration alter light availability and soil chemistry, and the influence of those effects on S. spontaneum suppression. In addition, I explored the potential use of agricultural legumes to suppress S. spontaneum through nutrient competition. Finally, I examined potential for using allelopahty as a tool for forest restoration and exotic species management both through a review of the literature and green house experiments.

I evaluated the response of S. spontaneum along a gradient of understory light conditions in single species plots of trees planted for restoration. S. spontaneum regeneration after planting restoration trees was most limited by light availability. Legume trees produce deeper shade than non-legume trees, and were more efficient at suppressing S. spontaneum. In addition, legume overstory species suppressed S. spontaneum abundance beyond the expected reductions associated with shade. S. spontaneum is nitrogen and phosphorus co-limited in our system in the absence of competition. However, although we find trends towards higher soil nitrogen and lower phosphorus under legume trees, greenhouse and field experiments provided weak evidence for both phosphorus competition and allelopathy to play roles in S. spontaneum suppression.

Overall, results emphasize the value of incorporating legume trees into restoration plantings where invasive S. spontaneum suppression is desired. Restoration practitioners should consider establishing mixed species stands dominated by legume tree species when reforesting areas dominated by S. spontaneum to expedite the reforestation process.