The Experts below are selected from a list of 321 Experts worldwide ranked by ideXlab platform
Paul Johnston - One of the best experts on this subject based on the ideXlab platform.
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a mobility model for classical swine fever in Feral Pig populations
Veterinary Research, 2008Co-Authors: George Milne, Chloe Fermanis, Paul JohnstonAbstract:We present a simulation model which explicitly captures the movement of wild animals over the landscape and the effect which herd mobility has on the temporal and spatial course of an epidemic. Using the example of classical swine fever in Feral Pig populations in the tropical savannas, we demonstrate that seasonal factors influencing population density and movement patterns are an important factor in the transmission of the disease. Pig population density is much greater at the start of the dry season than at the start of the wet season, with an epidemic most likely to occur if initiated at the start of the dry season. Spatial heterogeneity due to scarcity of water in the dry season causes herds to congregate around water sources. This concentration of herds, and the consequential isolation of sub-populations, reduces overall disease transmission compared with a model where the population is more evenly distributed over the landscape. The presence of adult male Pig herds, which travel over greater distances than family herds, is shown to increase the overall scale of an outbreak in the dry season by connecting together otherwise isolated family herds. Eradication strategies are more likely to be successful in the dry season if they target long-range adult male herds. Our simulation method is generic and is equally applicable to other diseases where the host species is mobile. classical swine fever / disease modelling / simulation / spatial model / Feral and wild animal populations
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A mobility model for classical swine fever in Feral Pig populations
Veterinary Research, 2008Co-Authors: George Milne, Chloe Fermanis, Paul JohnstonAbstract:We present a simulation model which explicitly captures the movement of wild animals over the landscape and the effect which herd mobility has on the temporal and spatial course of an epidemic. Using the example of classical swine fever in Feral Pig populations in the tropical savannas, we demonstrate that seasonal factors influencing population density and movement patterns are an important factor in the transmission of the disease. Pig population density is much greater at the start of the dry season than at the start of the wet season, with an epidemic most likely to occur if initiated at the start of the dry season. Spatial heterogeneity due to scarcity of water in the dry season causes herds to congregate around water sources. This concentration of herds, and the consequential isolation of sub-populations, reduces overall disease transmission compared with a model where the population is more evenly distributed over the landscape. The presence of adult male Pig herds, which travel over greater distances than family herds, is shown to increase the overall scale of an outbreak in the dry season by connecting together otherwise isolated family herds. Eradication strategies are more likely to be successful in the dry season if they target long-range adult male herds. Our simulation method is generic and is equally applicable to other diseases where the host species is mobile.
Heitor Miraglia Herrera - One of the best experts on this subject based on the ideXlab platform.
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the role played by sympatric collared peccary tayassu tajacu white lipped peccary tayassu pecari and Feral Pig sus scrofa as maintenance hosts for trypanosoma evansi and trypanosoma cruzi in a sylvatic area of brazil
Parasitology Research, 2008Co-Authors: Heitor Miraglia Herrera, Urbano Gomes Pinto De Abreu, A Keuroghlian, Tatiana Padua Tavares De Freitas, Ana Maria JansenAbstract:The Brazilian Pantanal has been considered one of the richest and most diverse wetland ecosystems in the world. It is occupied by cattle ranching, and a variety of wildlife species share the same habitats with domestic livestock. We investigated infections of Trypanosoma evansi and Trypanosoma cruzi in the sympatric suiformes-collared peccary (Tayassu tajacu), white-lipped peccary (Tayassu pecari), and Feral Pig (Sus scrofa) by parasitological, serological, and molecular tests. Additionally, we evaluated the health status of both positive and negative suiformes by hematological and biochemical parameters. The results show that peccaries and Feral Pigs play an important role on the maintenance of both T. evansi and T. cruzi in the Brazilian Pantanal. Health impairment was observed only in the white-lipped peccary infected with T. evansi. Despite presenting low T. evansi parasitemia, all infected white-lipped peccaries displayed low hematocrit values and marked leucopenia. The hematological values showed that the T. evansi infection is more severe in young white-lipped peccaries. The presented data show that Feral Pigs and peccaries are immersed in the transmission net of both trypanosome species, T. cruzi and T. evansi, in the Pantanal region.
Steven J Lapidge - One of the best experts on this subject based on the ideXlab platform.
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target specificity of Feral Pig baits under different conditions in a tropical rainforest
Wildlife Research, 2011Co-Authors: Andrew J Bengsen, Luke K P Leung, Steven J Lapidge, Iain J GordonAbstract:Context The mitigation of Feral Pig (Sus scrofa) impacts in north Queensland’s World Heritage tropical rainforests is constrained by the lack of an effective and target-specific poison baiting method. Aims This study aimed to determine whether easily implemented bait presentation methods or seasonal variation in bait acceptability could be used to selectively reduce the consumption of Feral Pig baits by non-target species. Methods We exposed manufactured Feral Pig baits to Pigs and non-target species in the field, and compared bait encounter, sampling and consumption rates for different functional groups of species among three different types of bait presentation and composition. We then exposed baits under different seasonal conditions and related bait encounter and consumption by different functional groups to seasonally variable phenomena. Key results Shallow burial greatly reduced bait consumption by most non-target species, but not dingoes (Canis lupus dingo). Nocturnal bait distribution and seasonal baiting were less useful. Pigs showed substantial seasonal variation in physiological condition, suggesting that Pigs should be more susceptible to consuming novel foods, such as baits, after periods of low rainfall. However, few Pigs consumed the manufactured baits used in this study. Conclusions Manufactured baits are not currently suitable for widespread use in the region. However, shallow burial should provide an effective method of reducing non-target bait-take if baits can be made more attractive and acceptable to Pigs and less acceptable to dingoes. Implications Future efforts to enable effective Feral Pig control in the region should focus on developing baiting materials that are more attractive to Pigs and unappealing to dingoes.
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additional toxins for Feral Pig sus scrofa control identifying and testing achilles heels
Wildlife Research, 2008Co-Authors: Peter Elsworth, Brendan D Cowled, Steven J LapidgeAbstract:A literature review was conducted in order to identify unique weaknesses in the physiology or metabolism of Pigs that could be targeted with specific chemicals (i.e. an ‘Achilles’ heel’ search). A promising weakness identified was the species’ susceptibility to methaemoglobin-forming compounds, most likely related to their uniquely low levels of methaemoglobin reductase. Further examination revealed that sodium nitrite is a cost-effective, readily available methaemoglobin-forming compound that is highly toxic to domestic Pigs, which has caused numerous accidental poisonings. Pen trials on Pigs showed that sodium nitrite delivered by gavage (>90 mg kg-1) and freely consumed in bait (>400 mg kg-1) caused rapid and lethal rises in methaemoglobin. Sodium nitrite appeared to be more humane than currently used toxins, with deaths following bait consumption being considerably quicker and with fewer symptoms (within 80 min of clinical signs beginning; clinical signs including infrequent vomiting, lethargy, ataxia and dyspnoea). The review also identified a second deficiency in the metabolism of Pigs, namely high sensitivity to selective inhibition of cytochrome P450 liver enzymes. This leads to potentially lethal interactions between various drugs, such as two antibiotics, monensin and tiamulin. A pen trial confirmed that the antibiotic combination in a single gavage dose was reliably and rapidly lethal to Pigs. However, its utility as a Pig toxin is low, because it was unpalatable to Pigs when delivered in bait and appeared to cause pain and suffering (leading to the early termination of pen trials). The findings presented here demonstrate the potential of sodium nitrite as an additional Feral Pig toxin.
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Feral Pig population structuring in the rangelands of eastern australia applications for designing adaptive management units
Conservation Genetics, 2008Co-Authors: Brendan Cowled, Jaclyn Aldenhoven, Inakwu O A Odeh, Tom Garrett, C Moran, Steven J LapidgeAbstract:Feral Pigs (Sus scrofa) are an invasive species in Australia. Their negative impact on conservation values has been demonstrated, and they are controlled in many areas in the rangelands of Australia. However, they are usually controlled over small, often ad hoc management units (MUs), and previous research has revealed that these MUs can be inadequate. Understanding Feral Pig population structuring can aid in the design of appropriate MUs. This study documents an approach to improving MUs for Feral Pig control in the rangelands of Australia. Feral Pigs from a 500,000 km2 region were genotyped with 13 polymorphic markers. Genetic analyses were used to identify population structure. Identified sub-populations were then related to geographical and environmental gradients with geographical information systems, regression analysis and with canonical correspondence analysis. Five sub-populations were identified. These were moderately differentiated, with relatively high-migration rates. Two sub-populations in drier, lower elevation areas overlapped, due to extensive migration, probably along the large, inland rivers and flood plains. Sub-populations in higher rainfall environments appeared less likely to migrate. Sub-population differentiation was also dependant on distance, indicating isolation by distance was present. A case study applying an adaptive MU to a previously controlled area is presented. Generally, however, MUs for Feral Pig control for natural resource protection and endemic disease eradication in the rangelands should take into account geographical size, but also geographic features, especially major rivers in low-rainfall areas.
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measuring the demographic and genetic effects of pest control in a highly persecuted Feral Pig population
Journal of Wildlife Management, 2006Co-Authors: Brendan Cowled, Steven J Lapidge, Jordan O Hampton, Peter B S SpencerAbstract:Substantial efforts have been made to identify the most effective practices for the control and management of invasive vertebrate pest species, such as the Feral Pig (Sus scrofa). We investigated the demographics, abundance, and molecular ecology of a persecuted Feral Pig population that was subjected to control. We then applied methodologies to determine if we could retrospectively quantify any changes in the population structure or dynamics of these Pigs. Feral Pig demographic and abundance parameters indicated that in this population of Feral Pigs, there were very few detectable changes between the two aerial culling years. We observed this despite environmental conditions being optimal for control. Genetic results indicated that Pigs culled in the latter 2004 cull were genetically identical to those Pigs that inhabited the area a year earlier. The genetic population was geographically larger than the sample area. These findings indicate that the recovery in Feral Pig density witnessed in the controlled area was not a result of reinvasion from a separate, genetically distinct population, but rather, it was the result of reinvasion from Feral Pigs outside the study area but within the same genetic population. Importantly, we were unable to detect any recent genetic bottlenecks. This approach has considerable potential for auditing the effectiveness of control programs of pest species and assessing the feasibility of impacting upon or locally eradicating many other free-ranging pest species.
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Efficacy of manufactured PigOUT® baits for localised control of Feral Pigs in the semi-arid Queensland rangelands
Wildlife Research, 2006Co-Authors: Brendan Cowled, Michelle Smith, Linton Staples, E. J. Gifford, Steven J LapidgeAbstract:Conservative population declines of 73% were recorded in three independent Feral Pig populations in Welford National Park, Queensland, when PigOUT® baits containing 72 mg of sodium fluoroacetate were used in a baiting program following prefeeding. Declines were measured using a prebaiting population census with remote cameras, followed by carcass recovery. The knockdown of susceptible Feral Pigs may have been higher than this, since any carcasses not recovered reduced the recorded efficacy. In addition, Feral Pigs know to have left the baiting area after trapping and telemetry-tagging, and subsequently not exposed to toxic baits, were included in the analysis. The use of remote cameras and carcass recovery appears to be a relatively accurate means of recording localised declines in Feral Pig populations. This method is applicable only when carcass recovery is possible, such as in open areas in the semi-arid rangelands. A decline of 86% of radio-tagged Feral Pigs attending bait stations was also recorded. Camera observations revealed no non-target consumption of baits. Measurement of sodium fluoroacetate–contaminated tissues from Feral Pigs showed that residues were too low to present a significant risk to recorded scavenging animals in the area. Some Feral Pigs vomited before death, with vomitus containing sodium fluoroacetate poison at high concentrations. No vomitus was consumed by non-target species. Almost all Feral Pigs were killed relatively rapidly after ingestion of sodium fluoroacetate and the signs observed in a small number of poisoned Feral Pigs did not indicate a significant welfare concern.
Creighton M. Litton - One of the best experts on this subject based on the ideXlab platform.
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Relationships between soil macroinvertebrates and nonnative Feral Pigs (Sus scrofa) in Hawaiian tropical montane wet forests
Biological Invasions, 2019Co-Authors: Nathaniel H Wehr, Creighton M. Litton, Noa K. Lincoln, Steven C HessAbstract:Nonnative Feral Pigs (Sus scrofa) are recognized throughout the New World as a highly significant introduced species in terms of ecosystem alteration. Similarly, nonnative soil macroinvertebrates (e.g. earthworms, ground beetles) invade and alter the structure and function of native habitats globally. However, the relationship between Feral Pigs and soil macroinvertebrates remains largely unknown. This study analyzed relationships between these taxa using nine sites located inside and outside of Feral Pig management units representing a ~ 25 year chronosequence of removal in tropical montane wet forests in Hawai‘i. Soil macroinvertebrates were sampled from plots categorized as: actively trampled by Feral Pigs, actively rooted by Feral Pigs, Feral Pigs present with no signs of recent activity, or Feral Pigs removed over time. In total, we found 13 families of primarily nonnative soil macroinvertebrates. Plots with active trampling correlated with lower total macroinvertebrate abundance, biomass, and family richness. Plots with active rooting were correlated with higher abundance of nonnative earthworms (Lumbricidae and Megascolicidae) and ground beetles (Carabidae). The abundance, biomass, and biodiversity of macroinvertebrates did not vary with time since Feral Pig removal. Collectively, these results indicate: (1) trampling by Feral Pigs negatively influences soil macroinvertebrates; (2) Feral Pigs either modify habitats while rooting thereby facilitating earthworm and ground beetle habitat use or selectively seek out target prey species of soil macroinvertebrates; and (3) removal of Feral Pigs has minimal impacts on soil macroinvertebrates over time. These results are important globally due to the broadly overlapping ranges of S. scrofa and nonnative macroinvertebrates.
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biology and impacts of pacific islands invasive species 14 sus scrofa the Feral Pig artiodactyla suidae
Pacific Science, 2018Co-Authors: Nathaniel H Wehr, Steven C Hess, Creighton M. LittonAbstract:Feral Pigs (Sus scrofa L.) are perhaps the most abundant, widespread, and economically significant large introduced vertebrate across the Pacific island region. Unlike many other nonnative invasive species, Feral Pigs have both cultural and recreational importance in the region, complicating their management. Today, Pacific island Feral Pigs are a mixture of several strains of domestic swine, Asiatic wild boar, and European wild boar. Due to their generalist diet and rooting behavior, Feral Pigs alter soils and watersheds and negatively impact native and nonnative flora and fauna. As a result, Feral Pigs have played a role in the extinction of several species of plants and animals on Pacific islands and have negative effects on both ecotourism and agricultural industries in the region. Despite numerous published studies on Feral Pigs in the Pacific island region, of which the majority include systematic analyses of original empirical data, some fundamental aspects of Feral Pig ecology remain poorly characterized, at least partly due to the remote and inaccessible environments that they often inhabit. To address these knowledge gaps, effort should be made to integrate research conducted outside the Pacific island region into local management strategies. This review summarizes the origins, history, ecology, environmental effects, and current management of Feral Pigs in the Pacific island region; integrates regional scientific findings with those of other insular and continental systems; and identifies current knowledge gaps requiring further research to inform the ecology and management of this impactful invasive species.
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Impact of nonnative Feral Pig removal on soil structure and nutrient availability in Hawaiian tropical montane wet forests
Biological Invasions, 2017Co-Authors: Michael S. Long, Creighton M. Litton, Christian P. Giardina, Jonathan Deenik, Rebecca J. Cole, Jed P. SparksAbstract:Conservation and restoration of ecosystems impacted by nonnative ungulates increasingly involves their removal and exclusion. While the influence of nonnative ungulate removal on plant communities is commonly monitored, impacts on underlying ecological processes are seldom quantified. Here we examined how nonnative Feral Pig ( Sus scrofa ) removal from Hawaiian tropical montane wet forests affects soil physical and chemical properties. Unique to this study, measurements were taken in paired sites inside and outside of five Feral Pig removal units representing a ~20 year, highly constrained chronosequence where other potentially confounding variables are held constant. Additional targeted measurements were taken inside and outside of a single exclosure in areas characterized by ‘low’ versus ‘high’ Feral Pig activity. Overall, nonnative Feral Pig removal increased stable soil aggregates and porosity, and decreased bulk density, water-filled pore space, and soil moisture content. Further, Feral Pig removal increased soil nutrient regeneration as evidenced by increased extractable cations, increased resin available NO_3 ^− and total inorganic N, and enriched foliar δ^15N. Increasing time since Feral Pig removal was positively related to net nitrification and total net inorganic N mineralization, and negatively related to pH and net ammonification. Results from both the chronosequence and targeted sampling were consistent in direction and support a central role of Feral Pig removal in modifying soil physical and chemical properties. Changes in soil properties following ungulate removal coincided with large increases in understory vegetation cover, highlighting the need to better understand aboveground-belowground linkages following nonnative ungulate removal.
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Invasive Feral Pigs impact native tree ferns and woody seedlings in Hawaiian forest
Biological Invasions, 2013Co-Authors: Molly J. Murphy, Faith Inman-narahari, Rebecca Ostertag, Creighton M. LittonAbstract:Invasive mammals can fundamentally alter native plant communities, especially on isolated islands where plants evolved without them. The globally invasive Feral Pig (Sus scrofa) can be particularly destructive to native plant communities. Tree ferns are an important understory component in many forests facilitating the establishment of a variety of species. However, the extent and effects of Feral Pig damage to tree ferns, and associated impacts on plant community regeneration, are largely unknown. We quantified the effect that Feral Pig damage has on tree fern growth, survival, and epiphytic woody seedling abundance over 1 year on 438 randomly selected tree ferns of three endemic species (Cibotium chamissoi, Cibotium glaucum, and Cibotium menziesii) in a Hawaiian montane wet forest with high tree fern and Feral Pig densities. Across all tree fern species, Feral Pigs damaged 13 % of individuals over 1 year. Compared with undamaged tree ferns, moderately- to heavily-damaged individuals had decreases of 4 to 27 % in trunk length increment and lost tenfold more fronds. Tree fern angle (standing, leaning, prone, or semi-prone) and woody seedling abundance co-varied with Feral Pig damage. Specifically, damaged tree ferns were more often prone or semi-prone and supported more seedlings, but also had annual mortality up to 34 % higher than undamaged tree ferns. Overall, Feral Pig damage had substantial negative effects on tree ferns by reducing growth and survival. Given the importance of tree ferns as regeneration sites for a variety of native plants, Feral Pig damage to tree ferns will likely alter future forest composition and structure. Specifically, Feral Pig damage to tree ferns reduces potential establishment sites for species that either regenerate preferentially as epiphytes or are currently restricted to epiphytic establishment due to ground rooting by Feral Pigs.
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response of understory vegetation to Feral Pig removal from hawaiian tropical montane wet forest
F1000Research, 2012Co-Authors: Rebecca J. Cole, Creighton M. LittonAbstract:− Increase soil erosion and sediment load in surface water runoff Response of understory vegetation to Feral Pig removal from Hawaiian tropical montane wet forest Rebecca J. Cole1 and Creighton M. Litton2 1Institute of Arctic & Alpine Research, University of Colorado at Boulder, rebecca.j.cole@colorado.edu; 2Department of Natural Resources and Environmental Management, University of Hawaiʻi at Mānoa, litton@hawaii.edu
George Milne - One of the best experts on this subject based on the ideXlab platform.
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a mobility model for classical swine fever in Feral Pig populations
Veterinary Research, 2008Co-Authors: George Milne, Chloe Fermanis, Paul JohnstonAbstract:We present a simulation model which explicitly captures the movement of wild animals over the landscape and the effect which herd mobility has on the temporal and spatial course of an epidemic. Using the example of classical swine fever in Feral Pig populations in the tropical savannas, we demonstrate that seasonal factors influencing population density and movement patterns are an important factor in the transmission of the disease. Pig population density is much greater at the start of the dry season than at the start of the wet season, with an epidemic most likely to occur if initiated at the start of the dry season. Spatial heterogeneity due to scarcity of water in the dry season causes herds to congregate around water sources. This concentration of herds, and the consequential isolation of sub-populations, reduces overall disease transmission compared with a model where the population is more evenly distributed over the landscape. The presence of adult male Pig herds, which travel over greater distances than family herds, is shown to increase the overall scale of an outbreak in the dry season by connecting together otherwise isolated family herds. Eradication strategies are more likely to be successful in the dry season if they target long-range adult male herds. Our simulation method is generic and is equally applicable to other diseases where the host species is mobile. classical swine fever / disease modelling / simulation / spatial model / Feral and wild animal populations
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A mobility model for classical swine fever in Feral Pig populations
Veterinary Research, 2008Co-Authors: George Milne, Chloe Fermanis, Paul JohnstonAbstract:We present a simulation model which explicitly captures the movement of wild animals over the landscape and the effect which herd mobility has on the temporal and spatial course of an epidemic. Using the example of classical swine fever in Feral Pig populations in the tropical savannas, we demonstrate that seasonal factors influencing population density and movement patterns are an important factor in the transmission of the disease. Pig population density is much greater at the start of the dry season than at the start of the wet season, with an epidemic most likely to occur if initiated at the start of the dry season. Spatial heterogeneity due to scarcity of water in the dry season causes herds to congregate around water sources. This concentration of herds, and the consequential isolation of sub-populations, reduces overall disease transmission compared with a model where the population is more evenly distributed over the landscape. The presence of adult male Pig herds, which travel over greater distances than family herds, is shown to increase the overall scale of an outbreak in the dry season by connecting together otherwise isolated family herds. Eradication strategies are more likely to be successful in the dry season if they target long-range adult male herds. Our simulation method is generic and is equally applicable to other diseases where the host species is mobile.