How much land is needed for feral pig hunting in Hawai‘i?

2014 ◽  
Vol 20 (1) ◽  
pp. 54 ◽  
Author(s):  
Steven C Hess ◽  
James D Jocobi
Keyword(s):  
Sus Scrofa ◽  
Minimum Amount ◽  
Land Area ◽  
Feral Pigs ◽  
The Public ◽  
Management Actions ◽  
In The Wild ◽  
Pig Meat ◽  
Sustained Yield ◽  
Feral Pig

Hunting is often considered to be incompatible with conservation of native biota and watershed functions in Hawai‘i. Management actions for conservation generally exclude large non-native mammals from natural areas, thereby reducing the amount of land area available for hunting activities and the maintenance of sustainable game populations. An approach which may be useful in addressing the necessary minimum amount of land area allocated for hunting in Hawai‘i is to determine the amount of land area necessary for sustaining populations of hunted animals to meet current levels harvested by the public. We ask: What is the total amount of land necessary to provide sustained-yield hunting of game meat for food at the current harvest level on Hawai‘i Island if only feral pigs (Sus scrofa) were to be harvested? We used a simplistic analysis to estimate that 1 317.6 km2–1 651.4 km2 would be necessary to produce 187 333.6 kg of feral pig meat annually based on the range of dressed weight per whole pig, the proportion of a pig population that can be sustainably removed annually, and the density of pig populations in the wild. This amount of area comprises 12.6–15.8% of the total land area of Hawai‘i Island, but more likely represents 27.6–43.5% of areas that may be compatible with sustained-yield hunting.

Observations on effects of feral pig (Sus scrofa) age and sex on diet

2015 ◽  
Vol 42 (6) ◽  
pp. 470 ◽  
Author(s):  
Jason Wishart ◽  
Steven Lapidge ◽  
Michael Braysher ◽  
Stephen D. Sarre ◽  
Jim Hone
Keyword(s):  
Sus Scrofa ◽  
New South ◽  
Food Material ◽  
Feral Pigs ◽  
Wildlife Species ◽  
South Wales ◽  
Slow Moving ◽  
Pig Management ◽  
Age And Sex ◽  
Feral Pig

Context Feral pigs (Sus scrofa) are a destructive invasive species that cause damage to ecologically sensitive areas. Management of biodiversity and of feral pigs assumes the diet of pigs of different ages and sexes are similar. Aims We aimed to investigate effects of feral pig age and sex on broad feral pig diet to identify potential at-risk native wildlife species so as to improve biodiversity and feral pig management. Methods Diet was determined by macroscopic analysis of the stomach content of 58 aerially shot feral pigs of mixed ages and sexes. The study occurred in the Macquarie Marshes, New South Wales, a Ramsar wetland of international significance. Results Feral pigs were largely herbivorous, with vegetable matter being found in all stomachs and contributing to a majority of the food material that was present in each stomach, by volume. Adult feral pigs had significantly more grasses and crop material in their stomachs than juveniles, while juveniles had significantly more forbs in their stomachs than adult feral pigs. Vertebrate prey items included frogs, lizard and snake, but no threatened wildlife species. Conclusions Juvenile and adult feral pigs differed in their diet, especially with regards to plant material, which has not been reported previously. There was, however, no difference in the consumption of vertebrate wildlife species between juvenile and adult, or male and female feral pigs. Slow-moving, nocturnal amphibians and reptiles were the most common vertebrate item recorded. Implications Biodiversity and feral pig management should recognise plant diet differences between demographic segments of the feral pig population. Further research is recommended to determine if diet differences also occur for threatened wildlife species, which will require more intensive nocturnal sampling.

Consumption of crops by feral pigs (Sus scrofa) in a fragmented agricultural landscape

2015 ◽  
Vol 37 (2) ◽  
pp. 194 ◽  
Author(s):  
Matthew Gentle ◽  
James Speed ◽  
Darren Marshall
Keyword(s):  
Sus Scrofa ◽  
Agricultural Landscape ◽  
Agricultural Landscapes ◽  
Economic Losses ◽  
Food Groups ◽  
Management Options ◽  
Crop Species ◽  
Feral Pigs ◽  
Food Items ◽  
Feral Pig

Feral pigs (Sus scrofa) consume and damage crops and impact the environment through predation, competition and habitat disturbance, although supporting dietary data are lacking in agricultural landscapes. This study was undertaken to determine the relative importance of food items in the diet of feral pigs in a fragmented agricultural landscape, particularly to assist in predicting the breadth of likely impacts. Diet composition was assessed from the stomach contents of 196 feral pigs from agricultural properties in southern Queensland. Feral pigs were herbivorous, with plant matter comprising >99% of biomass consumed. Crops were consumed more frequently than non-crop species, and comprised >60% of dietary biomass, indicating a clear potential for direct economic losses. Consumption of pasture and forage species also suggests potential competition for pasture with domestic stock. There is little evidence of direct predation on native fauna, but feral pig feeding activities may impact environmental values. Seasonal differences in consumption of crop, pasture or animal food groups probably reflect the changing availability of food items. We recommend that future dietary studies examine food availability to determine any dietary preferences to assist in determining the foods most susceptible to damage. The outcomes of this study are important for developing techniques for monitoring the impacts of feral pigs, essential for developing management options to reduce feral pig damage on agricultural lands.

The dynamics of feral pig (Sus scrofa) populations in response to food supply

2019 ◽  
Vol 46 (3) ◽  
pp. 191 ◽  
Author(s):  
Matthew Gentle ◽  
Anthony Pople ◽  
Joseph C. Scanlan ◽  
John Carter
Keyword(s):  
Food Supply ◽  
Sus Scrofa ◽  
Predictor Variable ◽  
Numerical Response ◽  
Initial Population ◽  
Population Densities ◽  
Juvenile Mortality ◽  
Management Actions ◽  
Eastern Australia ◽  
Feral Pig

Context Feral pigs (Sus scrofa) are highly fecund, and populations can increase rapidly under favourable conditions. Population size can also fluctuate widely, driven largely by changes in juvenile mortality in response to food availability, but these relationships have only been explored on a limited number of sites and over short periods. Aims The present study aimed to investigate and quantify the numerical response of feral pig populations to changes in their food supply in north-eastern Australia. Methods Pig population densities were determined from aerial surveys conducted over a 21-year period on 10 regional blocks (~2000–6000 km2) throughout the Queensland rangelands. Densities were used to calculate annual exponential rates of increase (r), which were then corrected for anthropogenic mortality (baiting and commercial harvesting). Six proxy measures of annual food supply, including rainfall, pasture biomass and pasture growth (using the AussieGRASS model), were calculated for each survey block, and assessed as predictors of corrected r. The rates of increase predicted from the first half of the data series were then applied to initial population densities to estimate successive pig densities during the second period in each bioregion. Key results The most parsimonious model of the numerical response had parameters common to three bioregions, with rainfall in the 12 months between surveys being the best predictor variable. Modelled densities for each bioregion were a good fit to actual, observed densities. Relationships between r and each measure of food supply at the individual block level were inconsistent. Conclusions Using rainfall as a measure of food supply, the numerical response relationship provides a method for predicting the dynamics of feral pig populations at the bioregional scale. Predicting population dynamics at any one site using this relationship is less precise, suggesting that differences in landscape composition affect utilisation of resources supporting population growth. Implications The results from the present study could be used to predict feral pig population changes at the bioregional level, supplementing or reducing the need for more frequent, expensive population surveys. This improved ability to predict fluctuations in regional feral pig populations can help guide future management actions.

Soil phosphorus predicts feral pig (Sus scrofa) occupancy, detection probability and feeding activity in a temperate montane rainforest

2016 ◽  
Vol 43 (4) ◽  
pp. 277 ◽  
Author(s):  
David M. Forsyth ◽  
Robert B. Allen ◽  
Roy K. J. Allen ◽  
Kathrin Affeld ◽  
Darryl I. MacKenzie
Keyword(s):  
New Zealand ◽  
Habitat Use ◽  
Detection Probability ◽  
Sus Scrofa ◽  
Soil Phosphorus ◽  
Feeding Activity ◽  
Occupancy Models ◽  
Feral Pigs ◽  
Soil P ◽  
Feral Pig

Context Feral pigs (Sus scrofa) have a wide global distribution that includes large parts of Australia and New Zealand. There is concern about the impacts of feral pigs on above- and below-ground flora and fauna, but little is known about their habitat use and feeding activity in temperate rainforests. Aims We evaluated the importance of abiotic and biotic variables hypothesised to influence seasonal and annual feral pig habitat use and feeding activity in a montane conifer–angiosperm rainforest in Te Urewera, North Island, New Zealand. Methods We used a grid of 25 remote-camera locations to collect feral pig images in a 100-ha area during the winters and summers of 2010 and 2011. Plant composition, solar radiation and soil fertility variables were determined for each camera-image area. Multiseason, multistate occupancy models and information-theoretic methods were used to evaluate how these variables related to feral pig occupancy and feeding. Key results Feral pigs occupied more camera locations in summer than in winter, and detection probabilities increased if piglets were present and with increasing soil phosphorus (P). Piglets were detected only in summer, and their detection probability increased with increasing soil P. The probability of detecting feral pigs feeding also increased with soil P and was higher in 2010 than 2011. Conclusions Feral pigs selected locations with high soil P, probably because those sites had more food than did locations with low soil P. Mast fruiting of tawa (Beilschmiedia tawa) has been hypothesised to increase feral pig recruitment, and the higher detection probability of piglets in summer 2010 followed a heavier tawa fruit fall. Implications Our study highlighted the usefulness of camera traps and occupancy models for understanding seasonal and annual dynamics of cryptic ungulate species in remote, rugged forests, and suggests that the impacts of feral pigs will be greatest in areas of high soil P following widespread tawa masting.

The effectiveness of aerial baiting for control of feral pigs (Sus scrofa) in North Queensland

1998 ◽  
Vol 25 (3) ◽  
pp. 297 ◽  
Author(s):  
J. Mitchell
Keyword(s):  
Sus Scrofa ◽  
Blood Samples ◽  
Feral Pigs ◽  
Population Reduction ◽  
Feral Pig

This study assessed the proportion of a feral pig population that consumed aerially distributed baits incorporating a non-toxic biomarker (iophenoxic acid). Baits were distributed at a rate of 18 baits km-2 over 70 km2 of a seasonally inaccessible habitat. A total of 102 feral pigs were then captured by trapping and ground-shooting. Blood samples from 63 adult feral pigs were analysed for the presence of the biomarker; 40 (63%) were considered to have consumed at least one bait. Ground-shooting and trapping over 6 days resulted in 18% and 16% population reduction respectively.

Quantifying efficacy of feral pig (Sus scrofa) population management

2019 ◽  
Vol 46 (7) ◽  
pp. 587 ◽  
Author(s):  
Peter J. Adams ◽  
Joseph B. Fontaine ◽  
Robert M. Huston ◽  
Patricia A. Fleming
Keyword(s):  
Sus Scrofa ◽  
Management Practices ◽  
Distance Sampling ◽  
Monitoring Program ◽  
Extreme Temperature ◽  
Population Management ◽  
Ecological Communities ◽  
Feral Pigs ◽  
Significant Difference ◽  
Feral Pig

Abstract ContextFeral pigs (Sus scrofa) are an increasing threat to agriculture and ecological communities globally. Although ground rooting is their most readily observable sign, feral pigs typically remain highly cryptic and their abundance and impacts are difficult to quantify. AimsThe aim of the present study was to evaluate the effect of current feral pig population management practices (trapping, baiting, no feral pig management) on feral pig abundance and digging impacts, using a BACI (before–after control–impact) experimental design at a landscape scale. MethodsA monitoring program was established to quantify both the abundance and digging impacts of feral pig populations within a temperate sclerophyll forest landscape using distance sampling. Transects were established across eight drinking water catchments where the whole catchment was the unit of replication for feral pig population management. Monitoring was carried out at 6-monthly intervals for 3 years, with no feral pig population management undertaken in the first year. In total, 367 feral pigs were trapped out of three catchments subject to trapping, and 26 were baited across two catchments subject to baiting with a commercial product (PIGOUT, Animal Control Technologies Australia, Melbourne, Vic., Australia). Three catchments were exempt from feral pig population management for the duration of this study. Key resultsFeral pig density within the overall study site was estimated as 1.127pigskm–2, resulting in 4580diggingskm–2year–1. There was no significant difference in feral pig density estimates observed among population management treatments or the treatment×year interaction term. An overall decrease in feral pig density across all catchments was attributed to extreme temperature and drought conditions experienced during the study. ConclusionsFeral pig populations demonstrate high resilience to current feral pig population management practices in the present study. The annual volume of soil disturbed by the numbers of feral pigs estimated across this study area is comparable to a commercial-scale resource extraction industry. We did not find significant differences in feral pig digging density among dominant vegetation types, but larger digs were associated with swamp vegetation. ImplicationsCurrent levels of feral pig population management did not reduce pig densities across eight catchments in the northern jarrah forest; therefore, more intensive population management is needed.

Are oestrous feral pigs, Sus scrofa, useful as trapping lures?

2005 ◽  
Vol 32 (7) ◽  
pp. 605 ◽  
Author(s):  
J. C. McIlroy ◽  
E. J. Gifford
Keyword(s):  
Sus Scrofa ◽  
National Park ◽  
Pilot Trial ◽  
Control Program ◽  
Cost Effective ◽  
General Technique ◽  
Feral Pigs

Eight feral pigs (two boars, four sows and two piglets) were caught in traps using oestrous sows as lures during a control program on a remnant pig population in part of Namadgi National Park during spring, 1990. The program was mostly based on aerial baiting with warfarin. No pigs were caught in traps containing anoestrous sows or in traps containing bait only. Seven unmarked pigs (caught seven days after the cessation of baiting) did not appear to have eaten any warfarin bait. In an earlier pilot trial, two boars were caught at a trap containing an oestrous sow, one of these again in a trap baited only with fermented grain, but no pigs were caught at a trap containing an anoestrous sow. Although not cost-effective as a general technique, this method could be useful in specific circumstances, such as eradication campaigns on islands, if the last few pigs are, or have become bait shy, or are impossible to cull by other methods.

Management of Publicly Owned Forests

1988 ◽  
Vol 64 (3) ◽  
pp. 193-198 ◽  
Author(s):  
G. Baskerville
Keyword(s):  
Productive Capacity ◽  
The Public ◽  
Management Actions ◽  
Proper Form ◽  
The People ◽  
Resource Dynamics ◽  
Industrial Use ◽  
Publicly Owned ◽  
Over Exploitation ◽  
Public Forests

For two reasons, planning and implementing management for publicly-owned forests is conducted in an environment that almost guarantees failure. First, group ownership is associated with a strong tendency towards over-exploitation (the tragedy of the commons), and second public ownership entails a heavy administrative overhead.The public allows industry to use publicly-owned forests and spends the revenue from exploitation on roads, schools health care, unemployment insurance and so on. The public owners are unwilling to limit industrial use of the forest to keep it in balance with the productive capacity of the forests because this would limit the benefits they receive and because they do not as individuals experience the shared cost of exploitation. Meanwhile, the people who own 90% of Canada's forests have until recently seen fit to spend only 5% of the taxes derived from their industrial use for maintaining their productive capacity. In effect the people of Canada are slum landlords. Like slum landlords, they have not returned to their properties enough money for their basic maintenance. The biggest problem in managing our public forests is in overcoming the owners' resistance to spending enough of the money generated by the forests to manage them in a technically adequate way over long period of time.The second major problem is the tendency of the agencies managing publicly-owned forests to shift from managing the forest to managing its use. This arises partly from the way in which the owners (the public) participate in the management process and partly because public money is used for management.The public owns the resource and must set goals. Unfortunately because they are so remote from the property and their understanding of resource dynamics is so trivial, the public tend to state vague goals accompanied by specific management actions with little thought to the cause/effect connections between them. Technically designed management tends to be over-ridden by socially comfortable solutions that do not solve the real management problems existing in the woods.Use of public funds necessitates creating a paper trail satisfactory to auditors. Consequently professionals responsible for managing the public forests find themselves spending more and more time ensuring that the administrative reporting of actions taken is up to date and in the proper form, and less and less time ensuring that the actions taken are the technically right ones to achieve the stated goals in the forest.

scholarly journals Captive-reared migratory monarch butterflies show natural orientation when released in the wild

2020 ◽  
Author(s):  
Alana A. E. Wilcox ◽  
Amy E. M. Newman ◽  
Nigel E. Raine ◽  
D. Ryan Norris
Keyword(s):  
North American ◽  
Danaus Plexippus ◽  
Release Site ◽  
Flight Simulator ◽  
Monarch Butterflies ◽  
The Public ◽  
In The Wild ◽  
Automated Telemetry ◽  
Proper Orientation ◽  
Captive Rearing

AbstractEastern North American migratory monarch butterflies (Danaus plexippus) have faced sharp declines over the last two decades. Although captive rearing has been used as an important tool for engaging the public and supplementing conservation efforts, a recent study that tested monarchs in a flight simulator suggested that captive-reared monarchs lose their capacity to orient southward during fall migration to their Mexican overwintering sites. We raised offspring of wild-caught monarchs on swamp milkweed (Asclepias incarnata) and, after eclosion, individuals were either tested in a flight simulator or radio-tracked in the wild using array of over 100 automated telemetry towers. While only 33% (7/39) of monarchs tested in the flight simulator showed strong southeast to southwest orientation, 97% (28/29) of the radio-tracked individuals were detected by automated towers south or southeast of the release site, up to 200 km away. Our results suggest that, though captive rearing of monarch butterflies may cause temporary disorientation, proper orientation is likely re-established after exposure to natural skylight cues.

scholarly journals Brasilia tapaculo (Scytalopus novacapitalis) seasonality and site occupancy in altitudinal riparian environments after non-natural burnings and feral pig invasion in Serra da Canastra National Park, Brazil

2020 ◽  
Author(s):  
I. L. D. Cunha ◽  
M. G. Reis ◽  
C. Z. Fieker ◽  
M. M. Dias
Keyword(s):  
National Park ◽  
Bird Species ◽  
Site Occupancy ◽  
Early Spring ◽  
Control Area ◽  
Southeastern Brazil ◽  
Breeding Period ◽  
Feral Pigs ◽  
Management Actions ◽  
Gallery Forests

Abstract The Brasilia Tapaculo, Scytalopus novacapitalis Sick, 1958, is a rare, geographically restricted, and endangered bird species that inhabits riparian vegetation of Cerrado, mainly Gallery Forests. In Serra da Canastra National Park, southeastern Brazil, wetlands are under threat due to frequent non-natural burnings and invasion by feral pigs, Sus scrofa, Linnaeus, 1758. We aimed to evaluate the possible effects of seasonal variations on S. novacapitalis records in undisturbed habitats and answer questions about how fire and feral pigs may affect site occupancy of the species. Transects alongside riparian environments were used to survey n=21 sites, totalizing 7.5 Km, from 2014 to 2019. Results indicated the season influenced both, spontaneous records and induced encounters by playback method, which were more abundant in breeding period, from early spring to summer. The use of playback significantly increased the amount of records in all seasons. The probability of site occupancy in all studied area was higher in late spring (ψ=0.91) and lower in autumn (ψ=0.73). In burned sites (n=8), the first post-fire month showed the lowest probability of occupancy, but there was a rapid recovery in 2nd month and stabilization similar to control area from the 3rd month ahead. After sites (n=11) were invaded by feral pigs, the estimation of site occupancy indicated a slight drop in first two months, but after the 3rd month of invasion the decreasing pattern enhanced the discrepancy with undisturbed areas. It is important to keep monitoring S. novacapitalis population and their threats, to subsidize management actions, especially to avoid frequently unusual burnings in riparian forests, and to block the access of feral pigs to wetlands.

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