Eradication Of Invasive Species Research Articles

Understanding intra and inter-archipelago population genetic patterns within a recently evolved insular endemic lineage

The recently evolved genus Tolpis Adans. has its major center of diversity located in Macaronesia. Although recent advances have been made to understand the relationships of Tolpis species within Macaronesia, little is still known about the genetic patterns and genetic diversity of the Azorean and Madeiran Tolpis populations. To achieve this, a set of 8 microsatellite loci (SSR) was applied to 478 individuals of Tolpis azorica and T. succulenta. Genetic structure analysis, in addition to a spatial analysis, confirmed the existence of geographically circumscribed genetic patterns allied to a barrier effect by the sea in the Azorean T. azorica and T. succulenta. A detailed analysis of T. azorica revealed three different genetic groups, each group being particular to a different Azorean sub-archipelago, while the analysis conducted with T. succulenta confirmed the occurrence of a differential grouping between individuals from Azores and Madeira populations. The impact of catastrophic volcanic events and intense humanization of the habitats is discussed, in view of the present genetic diversity and structure of the species. In general, T. azorica populations showed high F is values and some populations of T. succulenta both in Azores and in Madeira also showed signs of putative inbreeding. Conservation actions such as the eradication of invasive plant and animal species are advised but translocations of plants or diaspores between islands or between populations of a same island should not be attempted.

Passive recovery of an island bird community after rodent eradication

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 post-eradication) changes due to rodenticide application, and medium-term (5 years post-eradication) changes due to the absence of invasive rats. In the short term, Bald Eagle (Haliaeetus leucocephalus) numbers decreased from 24 individuals pre-eradication to two individuals <1 year post-eradication, but recovered to 10 individuals (42 % of pre-eradication) 5 years post-eradication, with all individuals nesting (63 % of the pre-eradication nesting). Five years post-eradication relative abundances of most terrestrial birds surveyed using point counts either significantly increased [Gray-crowned Rosy Finch (Leucosticte tephrocotis), Lapland Longspur (Calcarius lapponicus), Snow Bunting (Plectrophenax nivalis), Song Sparrow (Melospiza melodia)] or did not differ [Pacific Wren (Troglodytes troglodytes)]. Shorebirds also increased 5 years post-eradication with Black Oystercatchers (Haematopus palliates) increasing fivefold, and Rock Sandpiper (Calidris ptilocnemis) nesting increasing from one to five nests. We confirmed two species of ground nesting seabirds [Tufted Puffin (Fratercula cirrhata) and Leach’s Storm-petrel (Oceanodroma leucohoa)] as nesting (puffin) or engaged in courtship behavior (Storm-petrel) 5 years post-eradication. Our results indicate that despite the short-term impact on Bald Eagles, and without further human intervention, most terrestrial and marine birds have newly-colonized, re-colonized, or increased in abundance following the eradication of invasive rats.

Pollinator floral provisioning by a plant invader: quantifying beneficial effects of detrimental species

AbstractAimAlthough the negative effects of invasive species are globally recognized, little is known about the potential positive impacts they can have on other species in the ecosystems they invade. However, the persistence of invaders in a wide range of ecological communities may mean that they provide resources and refuge for threatened native species, or supplement ecosystem services.LocationAgroecosystems in the USA.MethodsWe use a 2‐year field experiment to explore the potential positive and negative impacts of an invasive thistle (Carduus acanthoides) on the composition of the resident community of foraging insects. The presence or absence of the thistle was the only difference in experimental and control plots comprising a background community of ten flowering annual species.ResultsWe demonstrate that the invasive thistle is both highly visited and strongly preferred by bees relative to other flowering species. Bee abundance was 302% higher and bee species richness 35% higher in habitat patches where the thistle was present compared to where it was absent. In addition, the abundance of Bombus species, a native group recently found to be in decline, was 479% higher when the thistle was present.Main conclusionsOur results suggest that, despite causing significant problems, the invasion of this non‐native species may also provide crucial benefits via floral resources for pollinators. Benefits, such as the floral resources that invaders provide to pollinators, should also be taken into account in conservation and invader management plans. Eradication or complete removal of invasive species which provision insects with floral resources could have unintended negative impacts on the associated pollinator community.

Impacts of invasive nonnative plant species on the rare forest herb Scutellaria montana

Invasive plant species and overabundant herbivore populations have the potential to significantly impact rare plant species given their increased risk for local extirpation and extinction. We used interacting invasive species removal and grazer exclusion treatments replicated across two locations in an occurrence of rare Scutellaria montana (large-flowered skullcap) in Chattanooga, Tennessee, USA, to assess: 1) competition by invasive Ligustrum sinense (Chinese privet) and Lonicera japonica (Japanese honeysuckle) and 2) the role of invasive species in mediating Oedocoilus virginianus (white-tailed deer) grazing of S. montana. Contrary to our hypothesis that invasive species presence would suppress S. montana directly via competition, S. montana individuals experienced a seasonal increase in stem height when invasive species were intact but not when invasive species were removed. Marginally significant results indicated that invasive species may afford S. montana protection from grazers, and we suggest that invasive species also could protect S. montana from smaller herbivores and/or positively influence abiotic conditions. In contrast to growth responses, S. montana individuals protected from O. virginianus exhibited a decrease in flowering between seasons relative to unprotected plants, but invasive species did not affect this variable. Although it has been suggested that invasive plant species may negatively influence S. montana growth and fecundity, our findings do not support related concerns. As such, we suggest that invasive species eradication efforts in S. montana habitat could be more detrimental than positive due to associated disturbance. However, the low level of invasion of our study site may not be representative of potential interference in more heavily infested habitat.

A human-centered approach to designing invasive species eradication programs on human-inhabited islands

Targeting human-inhabited islands for invasive species eradication campaigns layers social complexity on top of technical complexity. Attaining widespread support and cooperation for eradications requires programs designed to meet diverse stakeholder needs. The Tierra del Fuego archipelago serves as an informative case study and model for understanding and incorporating private landowner preferences into a proposed eradication program. We employed a human-centered approach to characterize landowner perceptions, preferences, and potential support for a large-scale initiative to eradicate the invasive North American beaver (Castor canadensis) from Tierra del Fuego. We used a factorial vignette survey to understand how attributes of an eradication program are related landowners' decisions to participate. Landowners rated four programs that randomly varied by contract length, required level of landowner involvement, institutional administrator, payment, social norms, and probability of a successful eradication. Landowners in Tierra del Fuego were generally more willing to participate under three conditions: (1) increased payments, (2) increased expectations of program success, and (3) low requirements for landowner involvement. Our results suggest that incorporating feedbacks into program design can increase public support, and that landowners in Tierra del Fuego may not express the same preference for autonomy that exists in other regions of the world. Understanding and incorporating stakeholder preferences, perceptions, and beliefs into management strategies is an ongoing challenge for conservation practitioners worldwide. The vignette survey approach provides a cost-effective, rapid, and scalable tool to document and incorporate local values into conservation program design. Programs built using a human-centered approach will complement landowners’ land-use objectives, increase cooperation, and ultimately improve conservation outcomes.

Mechanical Eradication of Invasive Fish Species Can Be Effective; Timing is Everything during Salmon Migration in Estuaries

FisheriesVolume 40, Issue 10 p. 483-483 Journal Review Mechanical Eradication of Invasive Fish Species Can Be Effective; Timing is Everything during Salmon Migration in Estuaries Sarah Harrison, Sarah Harrison AFS Editor sharrison@fisheries.org Search for more papers by this author Sarah Harrison, Sarah Harrison AFS Editor sharrison@fisheries.org Search for more papers by this author First published: 12 October 2015 https://doi.org/10.1080/03632415.2015.1100489Read the full textAboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article. Volume40, Issue10October 2015Pages 483-483 RelatedInformation

Managing Risk and Increasing the Robustness of Invasive Species Eradication Programs

AbstractInvasive species eradication programs can fail by applying management strategies that are not robust to potentially large but non‐quantified risks. A more robust strategy can succeed over a larger range of possible values for non‐quantified risk. This form of robustness analysis is often not undertaken in eradication program evaluations. The main non‐quantified risk initially facing Australia's fire ant eradication program was that the invasion had spread further than expected. Earlier consideration of this risk could have led to a more robust strategy involving a larger area managed in the program's early stages. This strategy could potentially have achieved eradication at relatively low cost without significantly increasing known and quantified risks. Our findings demonstrate that focusing on known and quantifiable risks can increase the vulnerability of eradication programs to known but non‐quantified risks. This highlights the importance of including robustness to potentially large but non‐quantified risks as a mandatory criterion in evaluations of invasive species eradication programs.

Reporting costs for invasive vertebrate eradications

The eradication of invasive species from islands is a conservation intervention proven to protect biodiversity, with more than 1200 successful vertebrate eradications implemented globally. The demand for eradication projects is increasing and practitioners are planning projects on increasingly larger, more remote and more technically challenging islands. Undertaking strategic planning for conservation requires information on both the cost and benefit of proposed actions, to determine the trade-off in selecting one project over another. To date the cost of eradication projects is disparately reported in the literature, an artefact of different reporting requirements based on where the eradication was undertaken, the scale of the project, the implementing agency and its accountabilities, and inconsistency in reporting all project component costs. Eradication projects have characteristics that allow more refined cost forecasting relative to other conservation initiatives, including a narrow set of major eradication techniques being used, a defined beginning and end point, and distinct project components. Here we present the major cost centres for eradication projects, including a dataset for a suite of rodent, ungulate and predator eradications, using a dataset of 46 eradications primarily from New Zealand, Ecuador and the USA. We found cost increased with island size for all eradication types except ground based rodent eradications. Using these standards to report project costs will improve the ability to evaluate and predict the cost of removing invasive animals from islands to protect native insular biodiversity.

Optimal dynamic control of invasions: applying a systematic conservation approach.

The social, economic, and environmental impacts of invasive plants are well recognized. However, these variable impacts are rarely accounted for in the spatial prioritization of funding for weed management. We examine how current spatially explicit prioritization methods can be extended to identify optimal budget allocations to both eradication and control measures of invasive species to minimize the costs and likelihood of invasion. Our framework extends recent approaches to systematic prioritization of weed management to account for multiple values that are threatened by weed invasions with a multi-year dynamic prioritization approach. We apply our method to the northern portion of the Daly catchment in the Northern Territory, which has significant conservation values that are threatened by gamba grass (Andropogon gayanus), a highly invasive species recognized by the Australian government as a Weed of National Significance (WONS). We interface Marxan, a widely applied conservation planning tool, with a dynamic biophysical model of gamba grass to optimally allocate funds to eradication and control programs under two budget scenarios comparing maximizing gain (MaxGain) and minimizing loss (MinLoss) optimization approaches. The prioritizations support previous findings that a MinLoss approach is a better strategy when threats are more spatially variable than conservation values. Over a 10-year simulation period, we find that a MinLoss approach reduces future infestations by ~8% compared to MaxGain in the constrained budget scenarios and ~12% in the unlimited budget scenarios. We find that due to the extensive current invasion and rapid rate of spread, allocating the annual budget to control efforts is more efficient than funding eradication efforts when there is a constrained budget. Under a constrained budget, applying the most efficient optimization scenario (control, minloss) reduces spread by ~27% compared to no control. Conversely, if the budget is unlimited it is more efficient to fund eradication efforts and reduces spread by ~65% compared to no control.

Understanding and integrating knowledge to improve invasive species management

Most successful control or eradication programs have been implemented in uninhabited regions, where little or no consideration of socio-political factors has been required. A considerable challenge for invasion scientists and decision-makers lies in controlling and eradicating species from inhabited regions, where challenges related to community stakeholder perceptions of the need to act, animal rights and uncertainty surrounding the presence and abundance of invasive species can threaten program development and implementation. We interviewed senior policy advisors and scientists who developed and implemented European red fox eradication policies on the inhabited island state of Tasmania, Australia. Our aim was to understand how they perceived that scientific evidence and community stakeholders’ knowledge and preferences should be involved in developing and implementing policy for fox detection and eradication. Respondents perceived that scientific evidence was best used in determining the need to act, assessing risks, designing eradication operations and monitoring progress. Overall, they perceived that involving community stakeholders was important in creating socially acceptable eradication operations that enable access to private land to implement eradication options. Community stakeholders’ knowledge was perceived, largely by scientists, to be based on misinformation, misconceptions and mistrust in science and, therefore, of limited value in informing policy. Community stakeholders were therefore not viewed as equal partners in the policy-making process by scientists. Only those stakeholders who performed a clear function were considered valuable. We propose that increased likelihood of successful eradication of invasive species from inhabited areas can be achieved by using a functional approach to stakeholder inclusion, to prevent dissent and conflict by legitimizing varied knowledge and capacity, leading to co-production of knowledge within a co-management governance system.

Predator-Free New Zealand: Conservation Country.

Eradications of invasive species from over 1000 small islands around the world have created conservation arks, but to truly address the threat of invasive species to islands, eradications must be scaled by orders of magnitude. New Zealand has eradicated invasive predators from 10% of its offshore island area and now proposes a vision to eliminate them from the entire country. We review current knowledge of invasive predator ecology and control technologies in New Zealand and the biological research, technological advances, social capacity and enabling policy required. We discuss the economic costs and benefits and conclude with a 50-year strategy for a predator-free New Zealand that is shown to be ecologically obtainable, socially desirable, and economically viable. The proposal includes invasive predator eradication from the two largest offshore islands, mammal-free mainland peninsulas, very large ecosanctuaries, plus thousands of small projects that will together merge eradication and control concepts on landscape scales.

Can we replace toxicants, achieve biosecurity, and generate market position with semiochemicals?

Biosecurity covers both long-term management of existing pests and the urgent government responses to alien invasive species which have yet to become fully established. Mating disruption, mass trapping and lure and kill systems all have potential to be used in pest management and against new incursions of certain types of organisms, predominantly moths and beetles. Straight chained lepidopteran sex pheromones have emerged as a source of potential market advantage in pest management, with trapping systems and residue-free multiple species disruption systems being increasingly adopted to reduce insecticide use and meet private stabndard. Semiochemicals can also offer new surveillance tools in pre-border biosecurity, greatly improving the chances for successful eradication of alien invasive species. However, a rising frequency of incursions of alien invasive species and consequent rise in official eradication programs due to globalisation points strongly to the need for further investment in the areas of discovery and development of surveillance and eradication technologies, from a sound knowledge of chemical ecology.

Quantifying the impact of Gambusia holbrooki on the extinction risk of the critically endangered red‐finned blue‐eye

Managing competing endangered and invasive species in spatially structured environments is challenging because it is often difficult to control invasive species without negatively impacting the endangered species. Effective management action requires an understanding of the factors affecting the presence and absence of each species so that promising sites for relocation of endangered species combined with eradication of invasive species can be identified. We investigate competing hypotheses about the factors affecting occupancy of the critically endangered red‐finned blue‐eye (Scaturiginichthys vermeilipinnis; hereafter ‘RFBE'), a native Australian fish with a global distribution that is restricted to a group of shallow artesian springs. RFBE are threatened by competition with invasive mosquito fish (Gambusia holbrooki), which are steadily colonizing the springs, resulting in local extinctions of RFBE in most cases. While hypotheses about the influences of Gambusia on RFBE exist, none have been tested with a quantitative model. We used a spatially‐structured two‐species occupancy modeling approach to examine the occupancy dynamics of these fish and tested competing hypotheses on how Gambusia occupancy affected RFBE. Gambusia occupancy had a strong negative effect on RFBE occupancy and colonization potential; increasing the probability of local extinction at a spring and decreasing the persistence probability of RFBE in a spring by 8.0% ± 2.7% (mean ± 1 SE). We found strongest support for the hypotheses that elevation and spring area influence colonization, and that spring area influences patch extinction probability. Using colonization and local extinction estimates for both species, we identify promising sites for eradication of Gambusia and relocation of RFBE.

Erratum: Biologies of betrayal: Judas goats and sacrificial mice on the margins of Mexico

Invasive species are the subject of much debate and attention. Social scientific analyses of alien species have focused on rhetoric about invaders, arguing that the discourse about invasive species reflects how people think about nature, culture and agency. In this article, I argue for a focus not only on discourse, but also on what happens in practice in the encounter between field scientists and invasive animals. Through ethnographic fieldwork on Guadalupe Island in Mexico, I analyze both the place of islands in the Mexican nation and invasive species eradication programs as examples of ‘care of the pest’, that is, projects in which scientists carefully tend to invasive organisms in order to produce knowledge about them. This knowledge is then used against the animals to exterminate them in a ‘biology of betrayal’, and occasionally, animals are enlisted into these projects to aid scientists in eradicating fellow members of their species. This article shows how changing perceptions of the value of island ecologies affected the use of the land and the fates of the animals on Guadalupe Island as the island was variously configured as laboratory, field site and slaughterhouse.

Tracking ghosts: combined electrofishing and environmental DNA surveillance efforts for Asian carps in Ontario waters of Lake Erie

Effective control or eradication of invasive species depends on their early detection at low abundance to enable timely management responses. In aquatic environments, the detection of rare or low-abundance species is challenging at best, and discriminating between detection failure (null) and true absence (zero) can be difficult. We developed and applied environmental DNA (eDNA) markers to screen for occurrences of bighead carp (Hypophthalmichthys nobilis), silver carp (H. molitrix), and grass carp (Ctenopharyngodon idella) in Ontario waters of Lake Erie, Lake St. Clair, and tributaries, as part of ongoing efforts to prevent these Asian carps from becoming established in the Great Lakes. A network of 180 sites in nearshore and tributary habitats, selected based on perceived risk of fish access or habitat suitability, were sampled using both boat electrofishing and/or eDNA sampling (948 water samples) throughout the 2012 open-water season. Electrofishing efforts did not capture any Asian carps, and no positive detections of environmental DNA for any of these species were obtained using both conventional and quantitative PCR. These combined results suggest that these Asian carp species are not yet established in Ontario waters of Lake Erie or Lake St. Clair, and highlight the value of combining conventional fisheries assessment and environmental DNA surveillance for assessing the potential presence of invasive species in freshwater systems.

Prioritizing islands for the eradication of invasive vertebrates in the United Kingdom overseas territories.

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 conservation benefit. Previous island prioritizations focused either on a narrow set of native species or on a small geographic area. We devised a prioritization approach that incorporates all threatened native terrestrial vertebrates and all invasive terrestrial vertebrates occurring on 11 U.K. overseas territories, which comprise over 2000 islands ranging from the sub-Antarctic to the tropics. Our approach includes eradication feasibility and distinguishes between the potential and realistic conservation value of an eradication, which reflects the benefit that would accrue following eradication of either all invasive species or only those species for which eradication techniques currently exist. We identified the top 25 priority islands for invasive species eradication that together would benefit extant populations of 155 native species including 45 globally threatened species. The 5 most valuable islands included the 2 World Heritage islands Gough (South Atlantic) and Henderson (South Pacific) that feature unique seabird colonies, and Anegada, Little Cayman, and Guana Island in the Caribbean that feature a unique reptile fauna. This prioritization can be rapidly repeated if new information or techniques become available, and the approach could be replicated elsewhere in the world.

The Nazi Comparison in the Debate over Restoration: Nativism and Domination

In this essay, I discuss the comparison between the restoration of natural environments and the Nazi project to develop a pure homeland for native species and authentic Aryan humans. There exists a metaphorical comparison between Nazi eliminationist policies regarding specific human populations and the eradication of invasive and non-native species in ecological restorations. Moreover, there are substantive environmental policies of the Nazi regime that appear to be similar to the goals and methodology of contemporary restoration practice. But there is also a more fundamental connection: the idea of the domination of the natural world. The idea of domination is the key to understanding both the process of ecological restoration and its real connection to Nazism.

Adverse outcome pathway and risks of anticoagulant rodenticides to predatory wildlife.

Despite a long history of successful use, routine application of some anticoagulant rodenticides (ARs) may be at a crossroad due to new regulatory guidelines intended to mitigate risk. An adverse outcome pathway for ARs was developed to identify information gaps and end points to assess the effectiveness of regulations. This framework describes chemical properties of ARs, established macromolecular interactions by inhibition of vitamin K epoxide reductase, cellular responses including altered clotting factor processing and coagulopathy, organ level effects such as hemorrhage, organism responses with linkages to reduced fitness and mortality, and potential consequences to predator populations. Risk assessments have led to restrictions affecting use of some second-generation ARs (SGARs) in North America. While the European regulatory community highlighted significant or unacceptable risk of ARs to nontarget wildlife, use of SGARs in most EU member states remains authorized due to public health concerns and the absence of safe alternatives. For purposes of conservation and restoration of island habitats, SGARs remain a mainstay for eradication of invasive species. There are significant data gaps related to exposure pathways, comparative species sensitivity, consequences of sublethal effects, potential hazards of greater AR residues in genetically resistant prey, effects of low-level exposure to multiple rodenticides, and quantitative data on the magnitude of nontarget wildlife mortality.

Optimal approaches for balancing invasive species eradication and endangered species management.

Resolving conflicting ecosystem management goals-such as maintaining fisheries while conserving marine species or harvesting timber while preserving habitat-is a widely recognized challenge. Even more challenging may be conflicts between two conservation goals that are typically considered complementary. Here, we model a case where eradication of an invasive plant, hybrid Spartina, threatens the recovery of an endangered bird that uses Spartina for nesting. Achieving both goals requires restoration of native Spartina. We show that the optimal management entails less intensive treatment over longer time scales to fit with the time scale of natural processes. In contrast, both eradication and restoration, when considered separately, would optimally proceed as fast as possible. Thus, managers should simultaneously consider multiple, potentially conflicting goals, which may require flexibility in the timing of expenditures.

Estimating eradication probabilities and trade-offs for decision analysis in invasive species eradication programs

Eradication of invasive species can have substantial benefits but programs often fail and have high costs. Costs can be reduced by substituting lower cost management actions for higher cost actions that have a similar impact on the probability of eradication. A first step towards minimizing costs is to determine all combinations of management actions that achieve eradication with the same probability, which is a form of trade-off analysis. Trade-off analysis can have a high computational cost when large numbers of management alternatives are compared with a complex spatial simulation model. Here, we apply a practical method for conducting trade-off analysis in which statistical methods are applied to data generated by a complex spatial model to derive a simpler model (the meta-model) that is used to determine trade-offs. We demonstrate this approach with a case study focusing on Australia’s largest eradication program, the campaign to eradicate red imported fire ants (Solenopsis invicta). Trade-offs were estimated for two surveillance methods, remote surveillance and ground surveillance, that are currently used in the eradication program. The methods are applied adaptively, with remote surveillance applied over all potentially infested locations (“area-wide surveillance”) and ground surveillance applied near remotely sensed detection points to find and remove remaining undetected individuals (“local surveillance”). The meta-modelling approach provided useful insights for management. When area-wide and local surveillance methods are applied adaptively, increases in the sensitivity of area-wide surveillance can allow for large reductions in the area of local surveillance and treatment. This can potentially result in substantial cost savings in circumstances where local search methods have a high cost.