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Potential public health benefits from eradicating rts in New Zealand cities and a tentative research agenda.

Available Online

Baker, Michael G.

Blaschke, Paul.

Mansoor, Osman D.

McIntyre, Mary.

Muellner, Petra.

Wilson, Nick. ? Mary McIntyre ? Paul Blaschke ? Petra Muellner ? Osman D Mansoor ? Michael G Baker

The eradication of some introduced pests such as rats, stoats and possums in New Zealand seems increasingly feasible with successful action to date in various cities (e.g. Wellington City) and with the governments national 2050 predator-free goal. Here we specifically detail the potential benefits of urban rat eradication and find these cover a wide range of topics including a potentially reduced risk of infection from at least seven zoonotic diseases (e.g. leptospirosis, toxoplasmosis, trichinellosis, murine typhus; and three enteric diseases). Other potential benefits include: psychological benefits from increased native bird life in cities; reduced damage to food supplies; reduced rat damage to building insulation and to building walls and roofing; and reduced fires in buildings associated with rat damage. However, there is considerable uncertainty on the size of such impacts and so we outline a tentative research agenda as a first step towards quantification of the likely key public health benefits of rat eradication.

Invasive rats on tropical islands: their population biology and impacts on native species

Available Online

Bunbury, Nancy

Harper, Grant. A,

The three most invasive rat species, black or ship rat Rattus rattus, brown or Norway rats, R. norvegicus and Pacific rat, R. exulans have been incrementally introduced to islands as humans have explored the worlds oceans. They have caused serious deleterious effects through predation and competition, and extinction of many species on tropical islands, many of which are biodiversity hotspots. All three rat species are found in virtually all habitat types, including mangrove and arid shrub land. Black rats tend to dominate the literature but despite this the population biology of invasive rats, particularly Norway rats, is poorly researched on tropical islands. Pacific rats can often exceed population densities of well over 100 rats ha?1 and black rats can attain densities of 119 rats ha?1, which is much higher than recorded on most temperate islands. High densities are possibly due to high recruitment of young although the data to support this are limited. The generally aseasonally warm climate can lead to year-round breeding but can be restricted by either density-dependent effects interacting with resource constraints often due to aridity. Apparent adverse impacts on birds have been well recorded and almost all tropical seabirds and land birds can be affected by rats. On the Pacific islands, black rats have added to declines and extinctions of land birds caused initially by Pacific rats. Rats have likely caused unrecorded extinctions of native species on tropical islands. Further research required on invasive rats on tropical islands includes the drivers of population growth and carrying capacities that result in high densities and how these differ to temperate islands, habitat use of rats in tropical vegetation types and interactions with other tropical species, particularly the reptiles and invertebrates, including crustaceans.

Invasive alien species on islands: impacts, distribution, interactions and management

Available Online

Holmes, Nick D

Meyer, Jean-Yves

Pagad, Shyama

Russell, James C.

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 peoples livelihoods on islands. We advocate for stronger collaborations among island countries and territories faced with the same IASs in similar socio-ecological environments.

Invasive ants as a biosecurity threat.

Available Online

Invasive ants are a diverse group of aggressive, competitive, dominating ant species that can rapidly establish and spread. Several ant species are amongst the most serious global invasive species. Their broad diets, nesting habits, ability to breed rapidly, high densitites and adaptibility to varied habitats make them excellent invaders. Agricultural economic, environmental and social wellbeing are threatened by these ants, many of which have been introduced to, and established in, many countries

Seabirds enhance coral reef productivity and functioning in the absence of invasive rats

Available Online

Carr, Peter.

Graham, Nicholas A. J.

Hoey, Andrew S.

Jennings, Simon.

MacNeil, M. Aaron

Wilson, Shaun K.

Biotic connectivity between ecosystems can provide major transport of organic matter and nutrients, influencing ecosystem structure and productivity, yet the implications are poorly understood owing to human disruptions of natural flows. When abundant, seabirds feeding in the open ocean transport large quantities of nutrients onto islands, enhancing the productivity of island fauna and flora. Whether leaching of these nutrients back into the sea influences the productivity, structure and functioning of adjacent coral reef ecosystems is not known. Here we address this question using a rare natural experiment in the Chagos Archipelago, in which some islands are rat-infested and others are rat-free. We found that seabird densities and nitrogen deposition rates are 760 and 251 times higher, respectively, on islands where humans have not introduced rats. Consequently, rat-free islands had substantially higher nitrogen stable isotope (?15N) values in soils and shrubs, reflecting pelagic nutrient sources. These higher values of ?15N were also apparent in macroalgae, filter-feeding sponges, turf algae and fish on adjacent coral reefs. Herbivorous damselfish on reefs adjacent to the rat-free islands grew faster, and fish communities had higher biomass across trophic feeding groups, with 48% greater overall biomass. Rates of two critical ecosystem functions, grazing and bioerosion, were 3.2 and 3.8 times higher, respectively, adjacent to rat-free islands. Collectively, these results reveal how rat introductions disrupt nutrient flows among pelagic, island and coral reef ecosystems. Thus, rat eradication on oceanic islands should be a high conservation priority as it is likely to benefit terrestrial ecosystems and enhance coral reef productivity and functioning by restoring seabird-derived nutrient subsidies from large areas of ocean.

Report of the Western South Pacific regionally workshop to facilitate the description of ecologically or biologically significant marine areas : subsidiary body on scientific, technical and technological advice sixth meeting, Montreal, 30 April - 5 May 2012

At its tenth meeting, the Conference of the Parties to the Convention on Biological Diversity (COP 10) requested the Executive Secretary to work with Parties and other Government as well as competent organisations and regional initiatives, such as the Food and Agriculture Organisation of the United Nations (FAo), regional seas conventions and action plans, and where appropriate, regional fisheries management organisations (RFMOs), with regards to fisheries management, to organise, including the setting of terms of reference, a series of regional workshop, with a primary objective to facilitate the description of ecologically or biologically significant marine areas through the application of scientific criteria in annex 1 to decision IX/20 as well as other relevant compatible and complementary nationally and intergovernmentally agreed scientific criteria, as well as the scientific guidance on the identification of marine areas beyond national jurisdiction, which meet the scientific criteria in annex 1 to decision IX/20.

Globally threatened vertebrates on islands with invasive species.

Available Online

Butchart, Stuart H M

Ceballos, Gerardo

Croll Donald A.

Genovesi, Piero Genovesi

Holmes, Nick D.

Spatz, Dena

Tershy, Bernie R

Zilliacus, Kelly M.

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 Nature) and invasive vertebrates on ~465,000 islands worldwide by conducting a comprehensive literature review and interviews with more than 500 experts. We found that 1189 highly threatened vertebrate species (319 amphibians, 282 reptiles, 296 birds, and 292 mammals) breed on 1288 islands. These taxa represent only 5% of Earth's terrestrial vertebrates and 41% of all highly threatened terrestrial vertebrates, which occur in

Hurricane disturbance accelerates invasion by alien tree Pittosporum undulatum in Jamaican montane rain forests

Island and Ocean Ecosystems, BRB

Available Online

Bellingham, Peter J.

Excurra, E.

Healey, John R.

Tanner, Edmund V. J.

Questions: Do past disturbance, soil nutrients, or species diversity predict the invasion success of the alien tree Pittosporum undulatum in an island montane rain forest? What are the consequences of its invasion for forest composition and species diversity? Location: Blue Mountains, Jamaica. Methods: Censuses of trees ? 3 cm DBH in permanent plots in four sites within ca. 7 ha; 19742004 (intensive sites) and in 16 plots within 250 ha; 19902004 (extensive plots). Results: Pittosporum was unrecorded in the intensive sites before a severe hurricane in 1988: by 2004 all four sites were invaded. Pittosporum had invaded 25% of the extensive plots in 1990 and 69% in 2004, where its basal area increased from 0.5 ± 0.4 (SEM) m2.ha?1 in 1990 to 2.8 ± 1.3 m2.ha?1 in 2004. It had zero stem mortality and diameter growth rate exceeded that of native species fourfold. Pittosporum's basal area in the extensive plots in 2004 was positively related to the stand basal area damaged in the 1988 hurricane and negatively related to soil N concentrations. Pittosporum invasion was unrelated to stand-level tree species diversity in the extensive plots but as its basal area increased over time the basal area of native species and stand-level diversity declined. Conclusions: There are no obvious functional attributes of Pittosporum unrepresented in the native tree flora although it has high photosynthetic efficiency compared with native trees. More widespread invasion of these forests by Pittosporum seems inevitable since hurricanes, which accelerated the invasion, affect these forests frequently.

Funtional Roles of Invasive Non-indigenous Plants in Hurricane-Affected Subtropical Hardwood Forests

Available Online

Freedman, Andrea.

Hoffstetter, Ronald H.

Horvitz, Carol. C.

McMann, Stephen.

Pascarella, John B.

Native forest species exhibit a well-known range of ecological roles with respect to natural disturbance regimes, from pioneer phase to mature phase, and they regenerate from a range of sources, including dormant seeds, seed rain, pre-established juveniles, and resprouts from damaged adults. In contrast, the ecological roles of invasive, non-indigenous species in forest communities after natural disturbances are not well understood. Some previous studies of invasive species have emphasized their weedy nature and their ability to colonize anthropogenic disturbances. Tropical hardwood hammock forest in southern Florida experience frequent disturbance by hurricanes. Our studies of forest regneration during two years following a recent severe hurricane suggest that invasive non-indigenous forest species exhibit the same range of ecological roles as native forest regeneration during two years following a recent severe hurricane suggest that invasive non-indigenous forest species exhibit the same range of ecological roles as native forest species and compete with native species for particular kinds of regeneration opportunities. To study ecological roles of non-indegenous species in regenerating forests after Hurricane Andrew, we set up four large study areas at each of three study sites that had differing amounts of hurricane-caused canopy disturbance. There were two pairs of 30 X 60 m research plots per site, and in each pair there was one control plot and one restoration plot; restoration areas were subject to an aggressive management program, focused on reducing non-indigenous vine cover. Within these study areas we subsampled vegetation in small study plots that were regularly spaced, and conducted vegetation censuses in April (the end of the dry season) and October (the end of the rainy season) for 2 yr, beginning in April 1993. We found that the source of regeneration for forest species was dependent upon the amount of canopy disturbance, the time since disturbance, and the autecology of the constituent species. Overall, 28% of the 90 species were non-indigenous: 34% of the vines (N=32) and 24% of other life-forms (N=58). Non-indigenous vines seemed to have a special role; not only could they compete with native vines, but they could also negatively affect the regeneration of other natives from a diverse array of sources including pre-established juveniles and resprouts from damaged adults. Both native and non-indigenous vine cover in unmanipulated study areas increased following the hurricane. Non-indigenous vine species had higher cover than native vine species, and many species formed dense "blankets." Non-indigenous species in general (not just vines) did not differ significantly from native species in seed mass, nor were they restricted to the pioneer type of life history. Many non-indigneous species had invaded forests prior to hurricane disturbance and had their own banks of pre-established juveniles; others recruited from dormant seeds, and seed rain, and/or respouts from pre-established adults. Based on information on source of regeneration and impact on native species, we propose a classification scheme for functional roles of non-indigenous invasive species in forests. To investigate whether non-indigenous taxa had roles in other geographic regions similar to those they had in Florida, we reviewed literature for 50 taxa belonging to genera that have species known to be invasive in southern Florida. We found that these taxa were invsive or had cogeners that were invsive in other geographic regions (Western Australis, the Mariana Islands, Hawaii, the rMascarene Islands, and South Africa). We propose that taxa predominantly retain their invasive, functional-role type across regions. Thus, studies of ecological roles of invasive species with respect to natural disturbance regimes in one region may help us predict invasive roles in other regions.

Land use history, hurricane disturbance, and the fate of introduced species in a subtropical wet forest in Puerto Rico

Island and Ocean Ecosystems, BRB

Available Online

Lugo, Ariel E.

Thomlinson, John

Thompson, Jill

Tropical forests are suffering from increasing intensities and frequency of disturbances. As a result, non-native species accidentally introduced or intentionally planted for farming, plantations, and ornamental purposes may spread and potentially invade undisturbed native forest. It is not known if these introduced species will become invasive, as a result of recurrent natural disturbances such as hurricanes. Using data from three censuses (spanning 15 years) of a 16-ha subtropical wet forest plot, we investigated the impact of two hurricanes on populations of plant species that were planted in farms and plantations that were then abandoned and from the natural spread of species introduced into Puerto Rico in the past. The populations of four species (Citrus paradis, Mangifera indica, Musa sp., and Simarouba glauca) changed little over time. Six species (Artocarpus altilis, Calophyllum calaba, Genipa americana, Hibiscus pernambucensis, Syzygium jambos, and Swietenia macrophylla) declined between the first two censuses after Hurricane Hugo, then increased again in Census 3 after Hurricane Georges. Spathodea campanulata gradually increased from census to census, while Coffea arabica declined. These introduced species represent only a small part of the forest basal area and few show signs of increasing over time. The number of stems per plant, new recruits, and the growth rates of these introduced species were within the ranges of those for native plant species. The mortality rates over both census intervals were significantly lower for introduced species (

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