Although wildlife conservation actions have increased globally in both number and complexity, the dearth of scalable, cost-effective monitoring hampers effective intervention to understand conservation efficacy. Automated sensors and computer aided analysis have expanded the tools available for conservation monitoring. For threatened and elusive seabirds, acoustic monitoring presents a cost-effective, scalable alternative to traditional monitoring methods that are limited by remote or inaccessible locations requiring skilled field personnel. A key assumption in monitoring population trends acoustically is that measures of acoustic activity are correlated with the relative nesting abundance of seabirds at colony sites. Here we tested the efficacy of acoustic activity as an index of seabird nesting abundance at colonies. Sensors recorded ambient noise at Forster's Tern (Sterna forsteri) breeding colonies in San Francisco Bay for two breeding seasons. We used an automated method (spectrogram cross-correlation) to detect and count tern advertisement calls from recordings. We calculated mean seasonal call rate and compared it to the mean active nest count at colonies. Our results show that acoustic activity was a reliable index of colony size among breeding sites and an accurate index of change in colony size between years (adj. R2=0.94, n=5, p<.01). Acoustic activity was a strong enough index to detect population differences anticipated by effective conservation actions. Acoustic activity was a more precise index when comparing within sites between years, than among different sites, likely due to differences in the sound environments of the small islands. Quantifying the relationship between acoustic activity and relative abundance is a fundamental step in designing effective and scalable acoustic monitoring programs to monitor the effectiveness of conservation actions for seabirds and other vocalizing wildlife.

Industrial fisheries threaten oceanic sharks and rays. Effective management and conservation responses require solutions that incorporate biological, ecological, and policy considerations. In this dissertation, I use an interdisciplinary approach to measure and mitigate fisheries impacts for data-poor but highly threatened pelagic elasmobranchs. First, I describe the quantity, composition, and potential impact of industrial tuna fishing on 22 elasmobranch species using catch data reported by global tuna fisheries and a catch estimation approach. I show that publicly accessible catch rates indicate that these fisheries report ~2.9 million individual sharks and rays per year, but that estimated catches are as much as five times higher. Importantly, these impacts are understudied: only 20% (15 of 76) of the examined populations had been formally assessed and of these, roughly 30% are overexploited. Given these findings, in the second chapter I focus on one particularly vulnerable group: manta and devil rays (collectively, Mobulids). I analyzed the genetic population structure of three species in the eastern Pacific Ocean and found weak but statistically significant population genetic structure among all four species. These findings suggest that Mobulids exhibit metapopulation structure and local selection occurring regionally in the eastern Pacific, and support the identification of unique regional units for conservation and fisheries management. Finally, and as a way forward, I assess the policy response of five large tuna Regional Fisheries Management bodies responsible for managing and mitigating to elasmobranch bycatch. Using a mitigation hierarchy framework, I show that current policies are not adequate to sufficiently reduce oceanic shark and ray bycatch, and make management, data, and transparency recommendations that are likely to reduce the impacts of bycatch on threatened sharks and rays.

Passive acoustic monitoring is a transformative tool for increasing the scale of ecological monitoring. The biggest challenges remain in analyzing large volumes of recordings to produce ecological information useful for decision making. Ecoacoustics, a holistic, quantitative analysis of soundscapes and their emergent properties is an appealing way to distill information from many recordings, but new tools require rigorous studies to measure their efficacy tracking ecological patterns. This thesis contains three studies testing the efficacy of ecoacoustic approaches to monitoring species and communities. The first study uses simulations to test if a variety of indices of soundscape complexity, intensity and differences can measure realistic bird community changes in simulated dawn choruses. In addition, I explore combining indices to increase predictive power, and how the addition of anthropogenic noise and changes in bird behavior impact the usefulness of acoustic indices. The second study examines the acoustic monitoring of Cassin’s Auklets (Ptychoramphus aleuticus), a chorusing colonial seabird that is notoriously challenging to monitor. I test how a traditional automated call detection compares to a novel approach based on energy spectrums of the entire soundscape to index auklet activity. I discuss how for some species, this approach may be more effective in indexing activity, and in this case is a reliable predictor or relative burrow density, and could be applicable for other nocturnal, vociferous seabirds. In the third study I move from single seabird species to seabird communities. I apply acoustic indices of soundscape differences, complexity and intensity to measure seabird restoration outcomes in the Western Aleutian Islands. I find that acoustic richness, and the spectral differences from a pristine reference island are predicted by years of seabird recovery and other factors that promote seabird recovery. Acoustic indices provided similar information to traditional and more laborious approaches. In summation, ecoacoustic approaches are a valuable part of the acoustic monitoring toolbox. Across all three studies, acoustic indices reflected meaningful ecological patterns, at a fraction of the time and effort needed for other approaches. This can greatly improve the scale and speed at which monitoring programs can inform management decisions and iteratively improve conservation outcomes.

Biodiversity and ecosystem function conservation face unprecedented challenges. Underfunding, incomplete policies, and backlogged assessments hinder conservation planning (Myers et al., 2000; James et al., 1999). In this dissertation, I seek to develop data-driven methods to inform strategic conservation of water and seabirds. Fresh water shortages threaten ecosystem function and human health (Georgakakos et al., 2014; Jiménez Cisneros et al., 2015). In Chapter 2, I addressed effective water conservation by consumers across the contiguous United States. I determined county-level water stress by relating annual water withdrawal to availability. I adjusted water stress by the potential savings from full adoption of common domestic water conservation actions, such as installing low-flow showerheads. I projected that, during a drought year, the majority of counties would remain water-stressed despite savings. Further, I identified the agriculture sector as the most common dominant water user, suggesting that meaningful consumer water savings should reduce dietary water use. Biodiversity loss is threatened with an average population decline of 68% for assessed species since 1970 (Almond et al., 2020). A foundational step in conservation is determining species’ relative extinction risk. In Chapter 3 I applied a metapopulation viability analysis (mPVA), engineered in partnership with the Conservation Action Lab and Tim Tinker, to 99 threatened seabird species. I indexed species by relative extinction risk and identified extremely threatened species. I compared the mPVA projections with IUCN Red List threat statuses to identify species that should be prioritized for reassessment and to inform resource allocations. After species have been targeted and prior to implementation, interventions should be evaluated for potential benefit. In Chapter 4 I used the mPVA to analyze the prescribed actions in New Zealand’s national recovery plan for 27 threatened seabird species. I simulated common conservation actions, such as translocation and invasive species removals, at the breeding population level and compared this to status quo scenarios. I found that the majority of species were not predicted to significantly benefit from prescribed interventions. This dissertation guides effective conservation planning by demonstrating means to assess current risk and project the benefits of conservation actions.

Species and ecosystems worldwide are threatened by human activities, and intensive conservation efforts are needed to slow the ongoing biodiversity crisis (Tittensor et al. 2014). Islands are crucial to the conservation of global biodiversity: in just 5.5% of the earth's land area, they contain a disproportionate amount of terrestrial species, including an estimated 19% of birds and 17% of rodents. Islands are also highly vulnerable to human impact; 77% of known terrestrial vertebrate extinctions have taken place on islands and 40% of critically endangered species currently inhabit them (Tershy et al. In press). The leading cause of extinction and endangerment on islands is introduced species (Tershy et al. In press). In particular, animals associated with humans, such as such as rats, mice, pigs, goats, rabbits, and cats, have become feral on a large percentage of the world's roughly 400,000 islands (Atkinson 1985). These invaders have a myriad of direct and indirect effects on insular species, such as overgrazing of native plants, predation of native animals, competition with natives for food and other resources, and alteration of important physical and chemical ecosystem processes (Croll et al. 2005, Towns et al. 2006, Fukami et al. 2006, Kurle et al. 2008, Spear and Chown 2009, Simberloff 2011, Medina et al. 2011).

The eradication of invasive mammals from islands is an increasingly utilized conservation tool with a strong record of mitigating or reversing much of the damage caused by invasions (Barun et al. 2011a). Nearly 1,100 successful eradications to date have removed invasive mammals from 750 islands globally (DIISE 2014). Ongoing developments in eradication technologies are creating opportunities to eradicate invasive vertebrates from increasingly large and complex islands (Howald et al. 2007, Burbidge 2011, Campbell et al. 2011). Consequently, national and regional government agencies and conservation organizations are increasingly investing in vigorous eradication programs on islands. However, the global scale of island invasions greatly outweighs the resources available to undertake eradication projects. To ensure that biodiversity conservation resources are allocated as effectively and efficiently as possible, islands must be prioritized for eradications.

In my dissertation I address the island prioritization problem comprehensively. First, I develop a statistical model that explains global island extinctions as a function of invasive mammal presence, native taxonomy, and island attributes (Chapter 1). I use this model to isolate and quantify the impacts of invasive mammals on globally threatened island vertebrate species, and to predict the benefits to these species from invasive mammal eradication. Then, I combine these predicted benefits with eradication cost estimates, and develop an optimization model that identifies sets of islands where specified conservation goals can be attained via eradication for the minimum cost (Chapter 2). Finally, I assess the importance of socio-political factors in global conservation planning (Chapter 3). Taken together, the sections of my dissertation synthesize global data on island biodiversity, threats, costs, and governance, and provide results and tools that strengthen global prioritization efforts for invasive mammal eradications on islands.

Human health and ecosystem health are intricately linked through ecosystem services and through common threats. For example, deforestation, resource overexploitation, pollution, and introduction of invasive species are the four main threats to biodiversity (Dirzo and Raven 2003, Dirzo et al. 2014), and these have also been linked to the emergence of pathogens of public health concern and overall human health issues (e.g. (Daszak et al. 2001, Patz et al. 2004, Wolfe et al. 2005, Epstein et al. 2006)). Non-native species, which often become invasive in ecosystems that have been anthropogenically disturbed and that have been depleted of or lack native competitors or predators (Allendorf and Lundquist 2003, Doherty et al. 2016), are also reservoirs of several pathogens that affect humans. Because they can reach large population sizes and displace other host species, invasive species can modify and potentially amplify disease transmission dynamics through the introduction of novel pathogens or through changes in community structure (Young et al. 2017). Invasive species are often found in close association to humans, usually as human commensals (e.g. peri-domestic rodents, cats, mosquitos), which can increase the risk of human exposure to pathogens transmitted or carried by these species. Thus, management of invasive species through population control, eradication (in the case of islands) or ecosystem management, which are frequently implemented as biodiversity conservation tools (Doherty et al. 2015, Jones et al. 2016a, Sokolow et al. 2016, Spatz et al. 2017), have the potential to also benefit human health. Although the relationship between ecosystem and human health has just recently emerged as an important area of study, there are few concrete examples of the potential for synergistic interventions benefiting both (Wolfe et al. 2005, Ostfeld et al. 2006, Herrera et al. 2017). Here I focus on the public health impacts of invasive cats (Felis catus) and through three case studies, I provide evidence of the potential for combined public health and conservation benefits of eradicating invasive cat populations from islands and controlling free-roaming colonies on continental areas.

Cats have been introduced to approximately 179,000 islands, and co-occur with people in approximately 560 of them (Medina et al. 2011, Threatened Island Biodiversity Database Partners 2014). Cats are the second most widespread invasive predator on islands and are responsible at least in part for 14% of all bird, mammal and reptile extinctions on islands (Doherty et al. 2016, Jones et al. 2016b). Free-roaming cats on the mainland are also opportunistic predators and in many cases are additionally subsidized directly with supplemental food or indirectly with peri-domestic rodents (Lepczyk et al. 2004, Baker et al. 2005). Management schemes for free-roaming populations range from complete elimination of the population (i.e. eradication) to varying degrees of population control (e.g. trap-neuter-release (TNR), trap-neuter-adopt or trap-euthanize). Most countries and many states in the USA have few, if any, regulations concerning cat ownership and cat owner responsibilities, making free-roaming cat population control inconsistent and difficult to enforce (LaCroix 2006). Programs such as TNR adhere more closely to the demands of cat advocates, resulting in negligible benefits to wildlife, high long-term management costs, and usually uncontrolled free-roaming cat colonies (Andersen et al. 2004, Foley et al. 2005). In theory, these forms of management can significantly reduce cat population sizes if they cover a large proportion of the population and are done consistently (Andersen et al. 2004). However, supplementary feeding, pet abandonment, and persistence of fertile females may attract cats from nearby colonies and increase local cat densities (Bengsen et al. 2015), eventually making trapping efforts a waste of resources. On the other hand, eradications are only implemented when the goal is to permanently eliminate cat populations and are thus only conducted in closed systems such as islands, requiring considerable financial investment, capacity building, and ongoing biosecurity measures to prevent reintroduction (Donlan and Wilcox 2007). Eradications on human-inhabited islands represent additional logistical, social and economic constrains because some invasive species have a social and/or economic value for island inhabitants (Oppel et al. 2011). As a result, successful eradication of domestic cat populations on human-inhabited islands have been limited to islands with no more than 1,000 people (Jones et al. 2016b).

Cats and other wild felids are the only known definitive hosts of Toxoplasma gondii, and infected cats can shed up to one billion or hundreds of million oocysts in their feces (Hill and Dubey 2002). Infection with T. gondii can cause miscarriage or severe ocular and neurological lesions in newborns, systemic disease in immunocompromised individuals, and has been associated with neurological disorders such as Alzheimer’s and schizophrenia (Brown et al. 2005, Mortensen et al. 2007, Torrey et al. 2007, Maenz et al. 2014, Ngô et al. 2017). Exposure to T. gondii oocysts (the environmental stage of the parasite) through contact with contaminated soil is one of the most common routes of T. gondii infection (Cook et al. 2000a, Spalding et al. 2005, Jones et al. 2009, Egorov et al. 2018). Soil-related activities such as gardening or having an occupation involving soil exposure are associated with high risk of T. gondii infection (Jones et al. 2001). There is currently no vaccine against T. gondii, and treatment is often limited to reducing the risk of congenital transmission in women who become infected during pregnancy, or severe illness in people with a compromised immune system (SYROCOT (Systematic Review of Congenital Toxoplasmosis) study group 2007, Robert-Gangneux and Dardé 2012). Following proper food handling and hygiene practices can reduce exposure to T. gondii (Bahia-Oliveira et al. 2017). However, because free-roaming cats contribute significantly to the environmental load of T. gondii (VanWormer et al. 2013a), implementing management strategies that effectively control cat populations can be a more effective approach for reducing environmental contamination at its source. Likewise, on the majority of islands that do not harbor native felids, the local environmental source of T. gondii can be eliminated through cat eradications.

To examine whether cat eradication or population control on islands could benefit human health by reducing the burden of T. gondii infection, I compared the seroprevalence and risk factors associated with T. gondii exposure in people on seven islands with variation in cat density, including one island in which cats were eradicated in the year 2000, and another island in which cats had never been present. I found that eradication of introduced cats on islands could significantly reduce human risk of exposure to T. gondii. Exposure to T. gondii was completely absent on the island that never had cats and near zero on the island where cats were eradicated. Furthermore, all island resident children born after cats were eradicated showed no evidence of exposure to the parasite. The odds of T. gondii infection were nearly five-fold higher in people that had cats near their homes. On islands with cats, we found no association between local cat density and T. gondii seroprevalence, suggesting that complete eradication rather than control of cat population densities is necessary to reduce public health impacts of T. gondii infection.

Understanding the burden of T. gondii infection is required to assess whether cat eradication can benefit human health while also reducing one of the main threats to native species. The burden of T. gondii infection can be further integrated into cost-benefit analyses of cat eradications to determine if the costs of T. gondii infection and biodiversity threats outweigh the socioeconomic costs of eradication. However, epidemiological information on T. gondii infection in people is only known for a small number of islands (N=18) where invasive cats co-occur with people and threatened island native species. This paucity of epidemiological information may be due to lack of reporting and/or limitations in public health services. To estimate the burden of T. gondii infection on islands where this epidemiological information was missing, I used T. gondii prevalence as a proxy for disease burden, and readily available ecological and socioeconomic variables as predictors. I found prevalence of T. gondii to be significantly and negatively correlated with human population size and with the per capita gross domestic product of islands. I used the results of the predictive model to estimate seroprevalence of T. gondii infection for the remaining islands where epidemiological information was missing. This predictive model can be used as a tool for identifying islands where T. gondii prevalence is high and where cat eradication has potential for benefiting human health. These models should be used with caution as further on-the-ground measurement is required before cost-benefit analyses are implemented.

Shedding and persistence of T. gondii oocysts in soil can change through time and can also be influenced by environmental factors, such as temperature and humidity as well as by cat demographic factors, such as cat density, juvenile abundance and supplemental feeding. To examine the spatial and temporal patterns of T. gondii prevalence, I sampled soil at free-roaming cat colonies present in community gardens, playgrounds and parks associated during three seasons (Spring, Summer and Fall) and in areas located along the coast and inland Central California, USA. I used seasons as proxies for temporal variation in both environmental and cat demographic variables, and geographic location of sites to examine spatial differences in prevalence of T. gondii in soil. I detected T. gondii only during Fall and in coastal sites. Results from this study suggest that environmental conditions play an important role in T. gondii presence, or at least persistence in soil, and cat abundance (or juvenile abundance) may be influencing T. gondii transmission dynamics. These results indicate that free-roaming cat colonies in spaces where people (including children) recreate is an important source of T. gondii.

In the past 500 years humans have been an immense driver of change capable of causing what is recognized as the sixth mass extinction (Ceballos et al., 2020). The extinction of species and populations, and the decline of populations numbers have been documented in terrestrial, freshwater and marine systems with alarming consequences for the coexisting species, and for the provision of ecosystem services crucial for humans (Dirzo et al., 2014; McCauley et al., 2015). Hawksbill sea turtle (Eretmochelys imbricata) is one in thousands of species threatened with extinction (IUCN, 2021). It is considered Critically Endangered on the IUCN Red List of Threatened Species and is estimated to have a global decline of nesting females of over 80% in just 3 generations (approx. 100 years; Mortimer and Donnelly, 2008). The main factors influencing its decrease are the direct harvest of individuals to sustain a global shell trade, the transformation of nesting and foraging habitats, bycatch mortality of juveniles and adults in industrial and small-scale fisheries, and a vulnerable life history with maturity at 20-40 years (Miller et al., 2019; Wallace et al., 2011b). This is particularly relevant for the Eastern Pacific hawksbill population, believed to be the most endangered of all hawksbill populations (Gaos et al., 2010; Wallace et al., 2010). Marine protected areas are an important tool to protect and manage marine species. In particular, marine reserves or no-take zones have proved to be beneficial due to the full protection from all extractive activities when they are well designed and both socially and policy supported (Gill et al., 2017). Nevertheless, spatial conservation planning for hawksbill sea turtles is hard due to their vast distribution ranges which can include several jurisdictional borders, and their dependence to two of the most productive coastal systems, reefs and mangrove estuaries, which are also important for small-scale fisheries (Aburto-Oropeza et al., 2008; Carrión-Cortez et al., 2013; Gaos et al., 2012b; Liles et al., 2011, 2017; Llamas et al., 2017). In response, strategies for the establishment of coastal marine protected areas have been expanded to prioritize restricted regions where species concentrate at vulnerable life history stages (i.e., nesting sites and foraging grounds) and to explicitly include local users in their design and enforcement (Rocliffe et al., 2014). Hawksbill turtles may particularly benefit from these strategies, but a deep understanding of the environmental conditions and habitat requirements that influence hawksbill’ occurrence in space and time is needed to evaluate this potential conservation tool (Guisan and Thuiller, 2005; Guisan et al., 2013). Northwest Mexico represents the northernmost limit for hawksbill distribution in the Eastern Pacific and is an important foraging region for the species (Martinez-Estevez et al., 2021; SEMARNAT, 2012). Also, it is the most productive fishing region with around 700,000 tons produced annually (Paez-Osuna et al., 2016), and a highly biodiverse system with an extensive variety of habitats, nearly 5000 marine invertebrates, and more than 1100 marine vertebrates described, including many endemic species (Brusca et al., 2005; Lluch-Cota et al., 2007; Munguia-Vega et al., 2018). Descriptions of the high abundance of organisms in this region were common for travelers and locals until the first half of the 1900’s (Saenz-Arroyo et al., 2005). For instance, Steinbeck et al. (1951) mentioned in the book The log from the Sea of Cortez: “The abundance of life here gives one an exuberance, a feeling of fullness and richness. The playing porpoises, the turtles, the great schools of fish which ruffle the water surface like a quick breeze, make for excitement. The sea here swarms with life, and probably the ocean bed is equally rich”. Sea turtles were a highly exploited group in northwest Mexico. For instance, hawksbills sustained an international shell trade and a regional trade of meat, eggs, and stuffed individuals until the 1960’s, and green turtles (Chelonia mydas) were taken by thousands per year in the late 1960’s and early 1970’s (e.g., 5,220 turtles/year at Laguna Ojo de Liebre, BCS; Early-Capistran et al., 2017; Saenz-Arroyo et al., 2005). Although hawksbill population declining made the trade not profitable, individuals have always been a valuable source in the region and illegal captures still occur. In Mexico, conservation strategies for hawksbills and other sea turtle species have been in place since 1979; however, lack of law enforcement and gaps of information on those important areas for the species have jeopardize the recovery of the population in the Mexican Pacific Ocean. In the following doctoral dissertation, comprised of three data chapters, I study the spatial ecology and habitat use of hawksbill turtles in northwest Mexico, and identify highly-used areas and actions for the species recovery and the conservation of its habitats. In Chapter 1, I surveyed 8 locations in the southwestern Gulf of California searching for hawksbill turtles. I measured and tagged individuals with unique ID tags and deployed satellite transmitters on twelve of them to analyze their movement patterns. By using a kernel density estimation analysis, I calculated home range areas and core areas of use of the individuals and overlapped them with current spatial conservation strategies. I demonstrated that hawksbills had highly restricted movements for periods of months to years. The areas they use are smaller than 5 km2, highlighting the need to protect them to increase the opportunities of population recovery. In Chapter 2, I studied the foraging ecology of hawksbill turtles in a foraging ground at the south of Isla San Jose, off the Baja California Peninsula, which is known to have high densities of the species. The foraging ground included three benthic habitat types: a sandy reef, a rocky reef, and a mangrove estuary. I used four complementary approaches to have the most complete information on how this species use the habitats: acoustic telemetry to track individual movements and determine the use of space, behavioral video recordings to identify behaviors and preferred food items, feces analysis to determine ingested food items, and benthic habitat surveys to determine availability of preferred food items. I demonstrated that tagged hawksbill turtles spent up to four years in the location and benthic habitat where individuals were initially caught. Sponges, algae, tunicates, and mangroves were the main available food categories for the species, and the mean percent cover of hawksbill benthic food was significantly greater in the mangrove estuary than in rocky and sandy reef habitats. These findings highlight the relevance of mangrove estuaries for Eastern Pacific hawksbills and reinforce the need to improve their management for hawksbill conservation and fisheries enhancement. Chapter 3 was materialized after a twenty day trip along the Gulf of California looking for hawksbills in mangrove estuaries and talking to local fishers about the current status of the species. That trip helped understand the differences between sites in the Baja California Peninsula, the islands, and mainland coast and provided the opportunity to use a collaborative database with hawksbill records from 1996 to 2019. I used the position data of hawksbill records to identify habitat type, and I developed a conservation index to determine the conservation status of hawksbill sites based on isolation, designated spatial protection status, presence of local engagement, and fishing pressure as factors influencing hawksbill presence and permanence. I demonstrated the relevance of the region for juvenile individuals and of reefs and mangroves as the main habitats used by the species. I identified highly used areas in northwest Mexico and I gave recommendations for the conservation of the species and its habitats. Together, these three chapters are the first regional analysis on the movement, habitat use and conservation of hawksbill turtles in the Gulf of California and northwest Mexico, with particular emphasis on foraging habitats and in-water monitoring. This regional approach brings important baseline information on those conditions that favor hawksbill presence and identifies highly used areas that require immediate protection. These findings also provide a framework to develop a regional hawksbill conservation program from which the species and local fishing communities can benefit.

The loss of biodiversity is one of the most acute global problems. Nowhere in the world are species more at risk of extinction than on islands. Islands represent only 3.2% of the earth’s land area, yet they contain a disproportionately higher amount of threatened and extinct biota compared to continents. The primary cause of extinction has been linked to introduced species, which occur on at least 80% of the world’s archipelagos. The compounding threats of habitat conversion, exploitation, pollution, and coastal hazards linked to climate change make conservation efforts appear complex and intangible. However, the eradication of invasive species from islands is an increasingly utilized conservation tool with a strong record of successes. Removing invasive species from islands has led to substantial conservation benefits and represents a key baseline activity to undertake to restore islands and increase resilience to global change. Consequently, national and local governments and conservation organizations are advancing eradication programs on islands, and there are ongoing developments in eradication technologies. Nonetheless, the global scale of threats to island biodiversity outweighs the resources available for conservation, and data gaps in the distribution of threatened species, and where they co-occurrence with threats, is lacking for most of the world’s islands.

In this dissertation, I fill major data gaps needed to address biodiversity loss on islands and identify islands where invasive species eradications can directly protect threatened species. I examine the distribution of globally threatened species, island characteristics, and threats from invasives, and analyze opportunities for conservation over short and long time frames in the context of invasive species management and global climate changes. Chapter one examines the global distribution of threatened island vertebrates, a well-studied group of taxa that are highly threatened, and whose conservation can subsequently benefit whole island ecosystems, including lesser known taxa. In Chapter 2, I further investigate the biogeography and conservation opportunities on islands for seabirds, one of the most threatened marine groups and one of the few groups that are almost completely reliant on islands to breed. Finally, in Chapter 3, I adapt existing methods in conservation priority setting to score and rank invasive mammal management opportunities on threatened seabird breeding islands, identifying where an eradication can be implemented and achieve the highest conservation benefits. In this chapter, I also examine the potential impact from climate change related coastal hazards and how flooding may impact the long-term success of conservation efforts. Together, these chapters provide insights into the biogeography of the most threatened island vertebrates and can be used to target conservation planning on the islands where biodiversity is in desperate need of conservation.

The overall objectives of this project were to: 1. Establish the nature and magnitude of the link among the physical dynamics of coastal upwelling, primary production, krill production, and productivity of the most important commercial fish species in California (market squid, Loligo opalescens); 2. Using the information from the first objective, construct models to explore various scenarios of the impacts of global climate change on nearshore krill and squid productivity.