Bernie Tershy

University of California, Santa Cruz | UCSC · Department of Ecology & Evolutionary Biology

Islands make up 5.3% of Earth's land area yet maintain an estimated 19% of bird species, 17% of rodents, 17% of flowering plants, and 27% of human languages. Species diversity is disproportionately threatened on islands in relation to the islands’ proportion of both global land area and species, with 61% of all extinct species and 37% of all critic...

Healthy ecosystems with intact biodiversity provide human societies with valuable services such as clean air and water, storm protection, tourism, medicine, food, and cultural resources. Protecting this natural capital is one of the great challenges of our era. Species extinction and ecological degradation steadily continues despite conservation fu...

It is widely recognized that trophic interactions structure ecological communities, but their effects are usually only demonstrated on a small scale. As a result, landscape-level documentations of trophic cascades that alter entire communities are scarce. Islands invaded by animals provide natural experiment opportunities both to measure general tr...

Protected area delineation and conservation action are urgently needed on marine islands, but the potential biodiversity benefits of these activities can be difficult to assess due to lack of species diversity information for lesser known taxa. We used linear mixed effects modeling and simple spatial analyses to investigate whether conservation act...

The hawksbill sea turtle Eretmochelys imbricata is categorized as Critically Endangered on the IUCN Red List and its population has declined by over 80% in the last century. The Eastern Pacific population is one of the most threatened hawksbill populations globally. Western Mexico is the northern distribution limit for hawksbill sea turtles in the...

Offshore wind energy development (OWED) is rapidly expanding globally and has the potential to contribute significantly to renewable energy portfolios. However, development of infrastructure in the marine environment presents risks to wildlife. Marine birds in particular have life history traits that amplify population impacts from displacement and...

Islands are global hotspots for biodiversity and extinction, representing ~ 5% of Earth’s land area alongside 40% of globally threatened vertebrates and 61% of global extinctions since the 1500s. Invasive species are the primary driver of native biodiversity loss on islands, though eradication of invasive species from islands has been effective at...

The seabird meta-population viability model (mPVA) uses a generalized approach to project abundance and quasi-extinction risk for 102 seabird species under various conservation scenarios. The mPVA is a stage-structured projection matrix that tracks abundance of multiple populations linked by dispersal, accounting for breeding island characteristics...

The Eastern Pacific hawksbill sea turtle population is one of the most endangered of all sea turtle species. Here, we examine the foraging ecology of 47 hawksbill turtles (40.5–90.3 cm CCL, mean = 54.1 ± 10.1 cm) around Isla San José, Gulf of California, Mexico by integrating information from passive acoustic telemetry, behavior recordings, fecal a...

Biodiversity conservation is limited by resources, data, and time for execution. To maximize efficacy, it is best if conservation plans are strategically evaluated for cost, feasibility, and likely impact prior to implementation. We present a framework to systematically examine the likely impact of proposed conservation plans for threatened taxa. A...

Little is known about the effects of large-scale breeding range expansions on the ecology of top marine predators. We examined the effects of a recent range expansion on the breeding and foraging ecology of Laysan albatrosses (Phoebastria immutabilis). Laysan albatrosses expanded from historical breeding colonies in the Central Pacific Ocean to the...

Eleven years after invasive Norway rats ( Rattus norvegicus ) were eradicated from Hawadax Island, in the Aleutian Islands, Alaska, the predicted three-level trophic cascade in the rocky intertidal, with native shorebirds as the apex predator, returned, leading to a community resembling those on rat-free islands with significant decreases in invert...

Understanding movement patterns and habitat preferences of endangered species during their most vulnerable life stages is a key step to developing effective conservation strategies that prevent extinctions. Hawksbills (Eretmochelys imbricata) are among the most-imperiled sea turtles and are generally thought to associate with very specific coral an...

The United Nations 2030 Agenda for Sustainable Development sets a framework of universal Sustainable Development Goals (SDGs) to address challenges to society and the planet. Island invasive species eradications have well-documented benefits that clearly align with biodiversity conservation-related SDGs, yet the value of this conservation action fo...

Climate change is exacerbating drought and water stress in several global regions, including some parts of the United States. During times of drought in the U.S., municipal governments, private water suppliers and non-profits commonly deploy advocacy campaigns and incentive programs targeting reductions in residential water use through actions incl...

Background: Toxoplasma gondii is a zoonotic parasite that can have severe implications for human health. Acutely infected cats shed environmentally resistant T. gondii oocysts in their faeces that contaminate soil, and soil can serve as a reservoir of infection for humans. Free-roaming domestic cats are thought to play an important role in environ...

Measuring restoration outcomes is essential, but challenging and expensive, particularly on remote islands. Acoustic recording increases the scale of monitoring inexpensively, however extracting biological information from large volumes of recordings remains challenging. Soundscape approaches, characterizing communities using acoustic indices, rapi...

Invasive alien species are a major threat to native insular species. Eradicating invasive mammals from islands is a feasible and proven approach to prevent biodiversity loss. We developed a conceptual framework to identify globally important islands for invasive mammal eradications to prevent imminent extinctions of highly threatened species using...

Table of islands, country or territory of ownership, invasive mammals and highly threatened species occurring on island, island rank reflecting conservation value, and timeframe assessed by socio-political survey in which an eradication could feasibly be initiated. Invasive mammal species listed are only those identified as having negative impact o...

Table of islands where no socio-political feasibility data was available during this study, country or territory of ownership, invasive mammals and highly threatened species occurring on island. Invasive mammal species listed are only those identified as having negative impact on highly threatened species and fall below island area and human popula...

Additional figures, tables and text supporting the main paper. (DOCX)

Author summary Infection with T. gondii can cause miscarriage or severe ocular and neurological lesions in newborns, systemic disease in immunocompromised individuals, and has been linked to mental disorders and neurodegenerative diseases such as schizophrenia, Alzheimer’s and movement disorders in adults. On the majority of islands, introduced cat...

Questionnaire adapted to the social context of communities living in the islands of Baja California, Mexico (Original version in Spanish). (DOCX)

Demographic characteristics of the sampled population and estimated density of introduced cats in the islands of Baja California, Mexico. (DOCX)

Risk factors for T. gondii seropositivity for the subset of people reporting having cats near their households. Based on a generalized linear mixed effects model with island as a random effect. Asterisks indicate the reference level for each predictor. (DOCX)

Raw data for analysis of seroprevalence and risk factors for Toxoplasma gondii infection in the seven human inhabited islands of Baja California, Mexico. (XLSX)

Feral cat density estimates for the human inhabited islands of Baja California, Mexico. (DOCX)

Association between number of cats reported for people with cats near their homes and seroprevalence of Toxoplasma gondii. (TIF)

Fitted seroprevalence of Toxoplasma gondii in men and women of the most common age group from the seven human-inhabited islands of Baja California, Mexico. (TIF)

Rat eradication has become a common conservation intervention in island ecosystems and its effectiveness in protecting native vertebrates is increasingly well documented. Yet, the impacts of rat eradication on plant communities remain poorly understood. Here we compare native and non-native tree and palm seedling abundance before and after eradicat...

Fifteen years of precipitation on Palmyra Atoll. Rainfall on Palmyra Atoll from 2002 to 2017. Survey month and two months prior to the survey period are highlighted (red dots = pre-eradication and blue dots = post-eradication). Horizontal lines indicate average rainfall and one standard deviation. (TIF)

Count of locally rare tree seedling plots. (DOCX)

Small-scale fisheries are in decline, negatively impacting sources of food and employment for coastal communities. Therefore, we need to assess how biological and socio-economic conditions influence vulnerability, or a community's susceptibility to loss and consequent ability to adapt. We characterized two Philippine fishing communities, Gulod and...

Global biodiversity loss is disproportionately rapid on islands, where invasive species are a major driver of extinctions. To inform conservation planning aimed at preventing extinctions, we identify the distribution and biogeographic patterns of highly threatened terrestrial vertebrates (classified by the International Union for Conservation of Na...

Resource partitioning is an important process driving habitat use and foraging strategies in sympatric species that potentially compete. Differences in foraging behavior are hypothesized to contribute to species coexistence by facilitating resource partitioning, but little is known on the multiple mechanisms for partitioning that may occur simultan...

Effective coastal conservation requires a better understanding of how human activities on land may directly and indirectly affect adjacent marine communities. However, the relationship between terrestrial and marine systems has rarely been considered in terrestrial and marine reserve design. Seagrasses are affected by land-based activities due to t...

Invasive mammals are an ongoing threat at many seabird breeding locations, while impacts from climate change can occur over broad time-scales. Combining management strategies for invasive mammal and climate change impacts is important for mitigating current threats and maximizing seabird survival into the future. We assessed all 713 islands with th...

Many neglected tropical zoonotic diseases are maintained by introduced mammals, and on islands the most common introduced species are rodents, cats, and dogs. Management of introduced mammals, including control or eradication of feral populations, which is frequently done for ecological restoration, could also reduce or eliminate the diseases these...

Invasive mammals on islands pose severe, ongoing threats to global biodiversity. However, the severity of threats from different mammals, and the role of interacting biotic and abiotic factors in driving extinctions, remain poorly understood at a global scale. Here we model global extirpation patterns for island populations of threatened and extinc...

Supplementary Figures 1-5, Supplementary Tables 1-5, Supplementary Methods and Supplementary References

Complete dataset, including all variables included in model selection. Sensitive species distribution have been removed at the request of experts who provided data.

Body mass data and associated references for threatened and extinct insular vertebrate species. Dataset includes each species' minimum and maximum body mass, when available, or body length (amphibians and reptiles) when mass data were unavailable. Also includes the average or estimated mass value that was used in the analysis for each species.

Iguanas are a particularly threatened group of reptiles, with 61% of species at risk of extinction. Primary threats to iguanas include habitat loss, direct and indirect impacts by invasive vertebrates, overexploitation, and human disturbance. As conspicuous, charismatic vertebrates, iguanas also represent excellent flagships for biodiversity conser...

1. Manta and devil rays of the subfamily Mobulinae (mobulids) are rarely studied, large, pelagic elasmobranchs, with all eight of well-evaluated species listed on the IUCN Red List as threatened or near threatened. 2. Mobulids have life history characteristics (matrotrophic reproduction, extremely low fecundity, and delayed age of first reproductio...

The number and scale of island invasive species eradications is growing, but quantitative evidence of the conservation efficacy of passive recovery is limited. We compare relative abundances of breeding birds on Hawadax Island (formerly named Rat island), Aleutian Archipelago, Alaska, pre- and post- rat eradication to examine short-term (<1 year po...

More than US$21 billion is spent annually on biodiversity conservation. Despite their importance for preventing or slowing extinctions and preserving biodiversity, conservation interventions are rarely assessed systematically for their global impact. Islands house a disproportionately higher amount of biodiversity compared with mainlands, much of w...

Measuring the response of native species to conservation actions is necessary to 27 inform continued improvement of conservation practices. This is particularly true for 28 eradications of invasive vertebrates from islands where up-front costs are high, actions 29 may be controversial, and there is potential for negative impacts to native (“non-tar...

Blue whales in the Northern Indian Ocean are a morphologically and acoustically distinct population restricted to these waters. Off Sri Lanka a portion of the population concentrates near shore where they are exposed to a range of anthropogenic threats. We review available data to determine anthropogenic threats/stressors faced by this population a...

We support the call of Wallach et al. (2015a) for a compassionate approach to conservation, and agree that any lethal control must be justified by a high probability of conservation gains and supported by relevant stakeholders. We believe that lethal control of invasive predators is justified when it will reverse the negative impacts of predators i...

Autonomous sensors and automated analysis have great potential to reduce cost and increaseefficacy ofwildlifemonitoring.Byincreasingsampling effort, autonomoussensors arepowerfulat detecting rareandelusivespeciessuchasthemarbledmurrelet(Brachyramphusmarmoratus).Newapproachesmustbetestedforcomparability to existing methodologies, so we compared the...

Invasive alien species are one of the primary threats to native biodiversity on islands worldwide. Consequently, eradicating invasive species from islands has become a mainstream conservation practice. Deciding which islands have the highest priority for eradication is of strategic importance to allocate limited resources to achieve maximum conserv...

Understanding how insular ecosystems recover or are restructured after the eradication of an invasive species is crucial in evaluating conservation success and prioritizing island conservation efforts. Globally, herbivores have been removed from 762 islands, most with limited active restoration actions following eradication. Few studies have docume...

2014): The effects of sex, tissue type, and dietary components on stable isotope discrimination factors (Δ 13 C and Δ 15 N) in mammalian omnivores makes every effort to ensure the accuracy of all the information (the "Content") contained in the publications on our platform. However, Taylor & Francis, our agents, and our licensors make no representa...

When a species becomes extinct, its ecological functions are lost as well. Taxon substitution is a controversial approach to restoring such functions via introduction of non-native species known to serve similar functions elsewhere. Due to the possibility of nontarget effects from such introductions, taxon substitution has been proposed and impleme...

Although wildlife conservation actions have increased globally in number and complexity, the lack of scalable, cost-effective monitoring methods limits adaptive management and the evaluation of conservation efficacy. Automated sensors and computer-aided analyses provide a scalable and increasingly cost-effective tool for conservation monitoring. A...

Seabirds are the most threatened group of marine animals; 29% of species are at some risk of extinction. Significant threats to seabirds occur on islands where they breed, but in many cases, effective island conservation can mitigate these threats. To guide island-based seabird conservation actions, we identified all islands with extant or extirpat...

Rodent eradications undertaken on tropical islands have had a lower success rate than those attempted in temperate regions. A recent project undertaken to eradicate Rattus tanezumi and R. exulans from the 3 islands comprising Wake Atoll is illustrative. R. tanezumi was successfully removed from all 3 islands. R. exulans was permanently eradicated o...