Invasive alien species (IASs) on islands have broad impacts across biodiversity, agriculture, economy, health and culture, which tend to be stronger than on continents. Across small-island developing ...states (SIDSs), although only a small number of IASs are widely distributed, many more, including those with greatest impact, are found on only a small number of islands. Patterns of island invasion are not consistent across SIDS geographic regions, with differences attributable to correlated patterns in island biogeography and human development. We identify 15 of the most globally prevalent IASs on islands. IAS impacts on islands are exacerbated through interactions with a number of other global change threats, including over-exploitation, agricultural intensification, urban development and climate change. Biosecurity is critical in preventing IAS invasion of islands. Eradication of IASs on islands is possible at early stages of invasion, but otherwise is largely restricted to invasive mammals, or otherwise control is the only option. Future directions in IAS management and research on islands must consider IASs within a broader portfolio of threats to species, ecosystems and people's livelihoods on islands. We advocate for stronger collaborations among island countries and territories faced with the same IASs in similar socio-ecological environments.
•Invasive rat eradication is a fundamental tool for island restoration.•Tropical islands have high biodiversity value and warrant protection from invasive rats.•Invasive rat eradications fail ...2–2.5times more often in the tropics than elsewhere.•Knowledge of the ecological conditions to maximise rat eradication success on tropical islands can be improved.•Invasive rat eradication leads to important species recovery and habitat protection.
Invasive rats have found their way to most islands throughout the world, where they have had and continue to have severe negative impacts on insular biota. Techniques developed in temperate regions to eradicate invasive rats from islands have proven to be one of the most powerful conservation tools available for island restoration. Tropical islands contain unique biodiversity also threatened by invasive rats, but eradication attempts in tropical environments have a higher failure rate. In particular rat eradications have failed more often on islands with high mean annual temperatures, and medium levels of annual precipitation which remain constant throughout the year. How these tropical ecological conditions interact to influence the likelihood of eradication success remains poorly understood. To synthesise current knowledge on the eradication of rats on tropical islands this special issue presents nine papers following a workshop reviewing tropical island rat eradications convened in Auckland, New Zealand in August 2013. These papers present state-of-the-art reviews of the field, best practice recommendations for operational implementation, novel research on rat ecology which will inform future eradication planning, and evidence of species recovery following rat eradication. In the future, biologists will need to contribute to our understanding of tropical island dynamics, particularly with respect to rat eradication, while eradication practitioners should seek to understand more deeply the role of tropical environments in eradication success, so that the implementation and success rate of tropical island rat eradications can increase, and the potential for tropical island restoration fully realised.
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 critically endangered species confined to islands. Languages are disproportionately threatened on islands in relation to land area with 11% of extinct languages and 25% of critically endangered languages on islands. Islands are a priority area for integrated conservation efforts because they have 14 times greater density of critically endangered terrestrial species and 6 times greater density of critically endangered languages than continental areas. Invasive species and habitat loss are the largest threats to island terrestrial species diversity. Proven management actions can reduce these threats, benefiting both local peoples and species diversity on islands.
Celotno besedilo
Dostopno za:
BFBNIB, DOBA, IZUM, KILJ, NMLJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
While invasive species eradications are at the forefront of biodiversity conservation, ant eradication failures are common. We reviewed ant eradications worldwide to assess the practice and identify ...knowledge gaps and challenges. We documented 316 eradication campaigns targeting 11 species, with most occurring in Australia covering small areas (<10ha). Yellow crazy ant was targeted most frequently, while the bigheaded ant has been eradicated most often. Of the eradications with known outcomes, 144 campaigns were successful, totaling approximately 9500ha, of which 8300ha were from a single campaign that has since been partially re-invaded. Three active ingredients, often in combination, are most commonly used: fipronil, hydramethylnon, and juvenile hormone mimics. Active ingredient, bait, and method varied considerably with respect to species targeted, which made assessing factors of eradication success challenging. We did, however, detect effects by active ingredient, number of treatments, and method on eradication success. Implementation costs increased with treatment area, and median costs were high compared to invasive mammal eradications. Ant eradications are in a phase of increased research and development, and a logical next step for practitioners is to develop best practices. A number of research themes that seek to integrate natural history with eradication strategies and methodologies would improve the ability to eradicate ants: increasing natural history and taxonomic knowledge, increasing the efficacy of active ingredients and baits, minimizing and mitigating non-target risks, developing better tools to declare eradication success, and developing alternative eradication methodologies. Invasive ant eradications are rapidly increasing in both size and frequency, and we envisage that eradicating invasive ants will increase in focus in coming decades given the increasing dispersal and subsequent impacts.
•316 invasive ant eradications have been conducted, of which 144 have been documented successful.•Active ingredients, baits, and methods used are highly unbalanced with respect to species targeted.•Ant eradications are in a phase of increased research and development, and a logical next step for practitioners is to develop best practices.•Targeted research on integrating natural history with eradication strategies and methodologies would improve this conservation tool.•Ant eradications are increasing in both size and frequency, and will become a greater focus of invasive species management in the future.
Abstract
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 halting or reversing these trends. A global compendium of this conservation tool is essential for scaling best-practices and enabling innovations to maximize biodiversity outcomes. Here, we synthesize over 100 years of invasive vertebrate eradications from islands, comprising 1550 eradication attempts on 998 islands, with an 88% success rate. We show a significant growth in eradication activity since the 1980s, primarily driven by rodent eradications. The annual number of eradications on islands peaked in the mid-2000s, but the annual area treated continues to rise dramatically. This trend reflects increases in removal efficacy and project complexity, generating increased conservation gains. Our synthesis demonstrates the collective contribution of national interventions towards global biodiversity outcomes. Further investment in invasive vertebrate eradications from islands will expand biodiversity conservation while strengthening biodiversity resilience to climate change and creating co-benefits for human societies.
Invasive species are the greatest threat to island ecosystems, which harbour nearly half the world’s endangered biodiversity. However, eradication is more feasible on islands than on continents. We ...present a global analysis of 1,224 successful eradications of invasive plants and animals on 808 islands. Most involve single vertebrate species on uninhabited islands, but plant and invertebrate eradications occur more often on inhabited islands. Inhabited islands are often highly modified and support numerous introduced species. Consequently, targeting a single invasive species can be ineffective or counterproductive. The impacts of other pests will continue and, in some cases, be exacerbated. The presence of people also creates regulatory, logistical and socio-political constraints. Real or perceived health risks to inhabitants, pets and livestock may restrict the use of some eradication tools, and communities or individuals sometimes oppose eradication. Despite such challenges, managing invasive species is vital to conserve and restore the unique biodiversity of many inhabited islands, and to maintain or improve the welfare and livelihoods of island residents. We present a brief case study of the Juan Fernández Archipelago, Chile, and discuss the feasibility of eradicating large suites of invasive plants and animals from inhabited islands while managing other invaders for which eradication is not feasible or desirable. Eradications must be planned to account for species interactions. Monitoring and contingency plans must detect and address any ‘surprise effects’. Above all, it is important that the local community derives social, cultural and/or economic benefits, and that people support and are engaged in the restoration effort.
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 eradication of invasive rats (Rattus rattus) from Palmyra Atoll, Line Islands, Central Pacific Ocean. Overall, seedling recruitment increased for five of the six native trees species examined. While pre-eradication monitoring found no seedlings of Pisonia grandis, a dominant tree species that is important throughout the Pacific region, post-eradication monitoring documented a notable recruitment event immediately following eradication, with up to 688 individual P. grandis seedlings per 100m2 recorded one month post-eradication. Two other locally rare native trees with no observed recruitment in pre-eradication surveys had recruitment post-rat eradication. However, we also found, by five years post-eradication, a 13-fold increase in recruitment of the naturalized and range-expanding coconut palm Cocos nucifera. Our results emphasize the strong effects that a rat eradication can have on tree recruitment with expected long-term effects on canopy composition. Rat eradication released non-native C. nucifera, likely with long-term implications for community composition, potentially necessitating future management interventions. Eradication, nevertheless, greatly benefitted recruitment of native tree species. If this pattern persists over time, we expect long-term benefits for flora and fauna dependent on these native species.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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 extinct vertebrates. Extirpations are driven by interacting factors including invasive rats, cats, pigs, mustelids and mongooses, native species taxonomic class and volancy, island size, precipitation and human presence. We show that controlling or eradicating the relevant invasive mammals could prevent 41-75% of predicted future extirpations. The magnitude of benefits varies across species and environments; for example, managing invasive mammals on small, dry islands could halve the extirpation risk for highly threatened birds and mammals, while doing so on large, wet islands may have little benefit. Our results provide quantitative estimates of conservation benefits and, when combined with costs in a return-on-investment framework, can guide efficient conservation strategies.
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 which is highly threatened with extinction. Indeed, island species make up nearly two-thirds of recent extinctions. Islands therefore are critical targets of conservation. We used an extensive literature and database review paired with expert interviews to estimate the global benefits of an increasingly used conservation action to stem biodiversity loss: eradication of invasive mammals on islands. We found 236 native terrestrial insular faunal species (596 populations) that benefitted through positive demographic and/or distributional responses from 251 eradications of invasive mammals on 181 islands. Seven native species (eight populations) were negatively impacted by invasive mammal eradication. Four threatened species had their International Union for the Conservation of Nature (IUCN) Red List extinction-risk categories reduced as a direct result of invasive mammal eradication, and no species moved to a higher extinction-risk category. We predict that 107 highly threatened birds, mammals, and reptiles on the IUCN Red List—6% of all these highly threatened species—likely have benefitted from invasive mammal eradications on islands. Because monitoring of eradication outcomes is sporadic and limited, the impacts of global eradications are likely greater than we report here. Our results highlight the importance of invasive mammal eradication on islands for protecting the world’s most imperiled fauna.
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