Rabbit Abundance Research Articles

Prolonged decline in the abundance of wild European rabbits Oryctolagus cuniculus and high immunity level over three years following the arrival of rabbit haemorrhagic disease

A free‐living population of European rabbits Oryctolagus cuniculus was monitored over three years, from 1996 to 1998, following the arrival of rabbit haemorrhagic disease (RHD) in 1995. The survey was based on nocturnal observations of individually marked rabbits to determine population size and on blood collection to determine whether rabbits carried RHD antibodies. We directly confirmed RHD outbreaks by examination of dead rabbits and detection of RHD virus (RHDV). Only one further recurrence of RHD was detected by this method, in 1996. Contrary to the initial outbreak, this second occurrence did not result in a major decrease in population size. No direct evidence of other outbreaks was detected in 1997 and 1998. However, the sparse data did not enable us to conclude that RHD was absent. Indeed, seroconversions in individual rabbits were noticed throughout the three years and the level of population immunity remained high, proving that either RHDV or RHD‐like viruses were present in the population. The influence of age, year and quarter on the serological status of the rabbits were analysed using a log‐linear model. The selected model showed that the proportion of rabbits with RHD antibodies varied with year and period of the year. Three years after the first occurrence of RHD, the population had not recovered to its level prior to the first outbreak. We assumed that predation by red foxes could be partly responsible for keeping the population low.

Reintroduction of the burrowing bettong Bettongia lesueur (Marsupialia: Potoroidae) to mainland Australia

The burrowing bettong was successfully reintroduced to the Australian mainland in 1992 after an absence of 50 years. The population, derived from 42 individuals translocated from a remnant population on an offshore island, has persisted for over seven years on the Heirisson Prong peninsula at Shark Bay in Western Australia. It has grown to over 260 individuals that are distributed widely through available habitat. The successful management of exotic European foxes and feral cats proved crucial to the outcome of the reintroduction. Factors contributing to the successful management of predators and to a reduction in their impact included: the choice of a narrow peninsula as the site for reintroduction (permitting cost-effective use of predator-proof fencing); effective baiting (fox and cat) and trapping (cat) strategies; the maintenance of an in situ breeding colony (to provide insurance against major loss of free-range animals to predators); choice of high quality habitat (providing reasonable cover and promoting a high and relatively stable rate of increase for bettongs, even during dry years), and choice of a site that was accessible for regular management visits. An abundance of European rabbits at the reintroduction site appeared not to be a limiting factor. The success of this reintroduction has stimulated a range of other reintroductions of endangered mammals to arid and semi-arid sites across Australia, particularly to peninsulas or other sites where exotic predators can be controlled effectively.

Defining key habitats for low density populations of Eurasian badgers in Mediterranean environments

Populations of Eurasian badgers ( Meles meles) living in Mediterranean ecosystems are of conservation concern. Deciduous forests are considered the main habitats of these badger populations in mountains, but key habitats for badgers have not been distinguished in Mediterranean lowlands. We provide a quantitative analysis of the overall habitat selection and preferences of Eurasian badgers in a Mediterranean area (Doñana, SW Spain). Data on 17 radiomarked animals in a rabbit-based population and three animals from another population with no single staple food were analysed by compositional analysis for determining selection and preference order, and Jacobs' index for absolute preference/avoidance. Results indicate that, in the rabbit-based area, badgers preferred well-preserved Mediterranean scrubland at every level of the analysis. In the area where badgers had no staple food there was no clear pattern. Rabbit abundance explained a significant amount of variance of the Jacobs' index in the rabbit-based area at all levels of the analysis. It is concluded that badgers are selecting those habitat types which hold key resources, such us food or shelter. Thus, not only deciduous forest and associated pastures, but also scrubland holding healthy rabbit populations are key habitats for Mediterranean badgers living in the Iberian peninsula.

Correlates of the population increase of Common Buzzards Buteo buteo in the West Midlands between 1983 and 1996

Buzzard density and distribution increased significantly in the West Midlands between 1983 and 1996. The number of soaring Buzzards counted in spring increased by 118% in the main range, 348% in the edge range and 231% overall. Although there was no significant linear trend in breeding success between 1950 and 1995, numbers of young fledged per breeding attempt were highest in the period 1980–95. This high productivity coincided with an increase in Rabbit Oryctolagus cuniculus abundance. Persecution levels, especially poisonings, appear to have been lower in the 1990s than during 1975–89. Increased productivity due to high Rabbit abundance, and higher survival rates due to reduced persecution, are likely to be the main factors responsible for the rapid increase in the Buzzard population in this area. Buzzards are increasing in numbers in other parts of Britain and Ireland and may now be more numerous than at any time this century.

Effects of surgically imposed sterility on free‐ranging rabbit populations

Summary 1. Demographic changes in response to surgically imposed female sterility were monitored in 12 free‐ranging rabbit populations in south‐western Australia over a 4‐year period. This was part of a research programme aimed at examining the potential for virally vectored immunocontraception to limit the abundance of rabbits (e.g. using a recombinant myxoma virus) and other mammalian pests. Sterility levels were 0%, 40%, 60% and 80% of all females in year 1, with a similar proportion of female recruits sterilized surgically in subsequent years. 2. There was a significant decrease in rabbit productivity with increasing sterility level. This was overcome by increased survival of kittens and adults on the high‐sterility sites, such that the base‐level numbers of rabbits were maintained, and mean annual rates of increase (r) were near zero for all treatments in all years. However, in the high‐sterility populations this compensation was insufficient to overcome the effects of sterility totally, and there was a marked decrease in the seasonal peaks in rabbit abundance for these treatments. 3. Survival and recruitment were dependent upon the level of sterility, and consequently the density of rabbits, with greatest survival of adult rabbits occurring on the 80% sites. Survival of sterile females was greater than that of other adults, probably because of their increased ability to maintain body condition during times of low pasture biomass (summer drought). Thus two density‐dependent processes were identified: the first was operating through increased survival of juvenile rabbits, the second through increased adult survival, particularly sterilized females. 4. Because the proportional impact of immigration was greater (i.e. immigrants constituted a greater proportion of the population) and emigration was less, from the 80% sites, the effects of sterility may have been underestimated on these sites. 5. The abundance of European rabbit fleas, a vector of myxomatosis, was significantly lower on the 80% sites, but this did not appear to affect the transmission of myxoma. Myxomatosis occurred as an annual epizootic in three of four years, with > 90% of rabbits on site after each epizootic testing positive for myxoma antibodies. 6. To achieve a sustained long‐term reduction in rabbit abundance, 60–80% of female rabbits would need to be prevented from breeding. This could be achieved by a recombinant strain of myxoma provided the strain retained good transmissibility and all infected rabbits became sterile for life.

Relationships between herbivore abundance and browsing damage in Tasmanian eucalypt plantations

Summary In Tasmania, Australia, eucalypt seedlings growing in commercial forestry plantations are often damaged by mammalian herbivores. There is presently a poor understanding of (i) the relationship between the abundance of herbivores and damage levels; and (ii) the effect that 1080 poisoning, the most frequently employed damage control technique, has on herbivore abundance. In this study, the abundance of four herbivore species was monitored at 35 first year eucalypt plantations. Forestry companies carried out 1080 poisoning operations at 28 of the plantations and no damage control was attempted at the remaining seven. When average scat deposition rates for each herbivore were regressed against levels of browsing damage, no significant relationships were observed for the Bennett's wallaby, pademelon or rabbit. However, there was a highly significant linear relationship (r = 0.537) between damage severity and average scat deposition rate for the brushtail possum. This suggests that managers may need to review the importance of this species as a contributor to damage. Poisoning operations resulted in an initial and sustained reduction in the abundance of pademelons on plantations. Poisoning did not result in an initial reduction in the abundance of the Bennett's wallaby and possum. However, in the long term, poisoning reduced the rate at which the abundance of these species increased. Poisoning had no apparent effect on rabbit abundance.

Niche relations among three sympatric Mediterranean carnivores.

Previous studies carried out in the Doñana National Park reported that red foxes (Vulpes vulpes) were killed by Iberian lynxes (Lynx pardinus), whereas similar-sized Eurasian badgers (Meles meles) were not. Therefore, we predicted that fox would avoid lynx predation risk by niche segregation whereas we did not expect such a segregation between badger and lynx. As an approach for evaluating our predictions, we compared their diet, activity patterns, and habitat use in an area of Doñana where the three carnivores are sympatric. Lynxes preyed almost uniquely on European rabbits (Oryctolagus cuniculus), and though badgers and foxes were omnivorous, rabbits also were a major prey, resulting in high overlaps throughout the year. However, badgers preyed largely on small rabbits, whereas lynxes and foxes preyed mainly on medium-sized rabbits. There were also interspecific differences in activity patterns. Maximum levels of activity among lynxes were during sunrise and dusk (49-67%). Foxes were most active during dusk and night (34-67%), and badgers were mainly nocturnal (53-87%). Though there were seasonal differences in the amount of activity of each species, specific activity patterns changed little throughout the year. There was a strong difference in annual habitat use by the three species (P < 0.0001). Lynxes used mainly the Mediterranean scrubland during both the active (PMAX) and the resting (PMIN) periods. During PMIN, foxes used the Mediterranean scrubland intensively (40% of locations on average), but during PMAX, they used the pastureland much more intensively despite this habitat being poorer in their main prey (rabbits). As a consequence, foxes and lynxes exhibited segregation in their habitat use during the active period. Badgers also used the Mediterranean scrubland intensively, especially during PMIN. There were no seasonal differences in habitat use for lynx and fox, but there was for badgers (P < 0.015). Within the study area, the three species selected habitat suggesting they were sensitive to factors such as vegetation and prey abundance. However, in general, carnivore habitat use did not correlate with rabbit abundance. We propose that foxes avoided lynxes by using, during activity, habitats not frequented by lynxes, and that a low predation risk associated with the distinctive foraging mode of badgers may facilitate its coexistence with other carnivores.

The use of sighting data to analyse Iberian lynx habitat and distribution

Summary 1. Over a large part of its very restricted and fragmented range, Iberian lynx Lynx pardinus occur in remote mountainous country at low density, where the only information about the species comprises records of incidental sightings obtained by inquiry. In this study we developed an approach for quantifying lynx–habitat relationships and distribution patterns from sighting data, using records from western Algarve (Portugal) in 1990–95. 2. Habitat was described in terms of land cover, topography, human disturbance and rabbit abundance, in 25‐km2 cells surrounding lynx sightings and at random locations within the study area. 3. Lynx sightings were consistently associated with predictable habitat features. Sighting probabilities estimated from a logistic regression model increased with the abundance of rabbits and the proportion of land covered by tall Mediterranean maquis, and declined with road density and the amount of developed land. This model identified correctly 85·7% of lynx sightings; at the same time only 20·7% of the random locations were misclassified. 4. Indices of human presence were never associated positively with lynx sightings, suggesting that observation patterns were not influenced by the spatial distribution of potential observers. 5. Kriging was used to interpolate spatially between sighting probabilities derived from the logistic model in order to produce a map of sighting potential for the Iberian lynx in western Algarve. Jack‐knife resampling assessed the accuracy of this map. Three well‐defined areas of high sighting potential were identified, probably representing the lynx core areas in this region. 6. Our analysis of lynx sighting records suggests that these data may provide a first approximation to lynx habitat and distribution when further information is lacking. The application of this approach to other rare and reclusive species is discussed.

Factors affecting the numbers and breeding success of Stone Curlews Burhinus oedicnemus at Porton Down, Wiltshire

The numbers and breeding success of the Stone Curlew Burhinus oedicnemus, a rare bird in the UK, were studied on chalk downland at Porton Down, Wiltshire, from 1987 to 1996. The number of pairs varied annually between nine and 19 and was positively correlated with spring counts of Rabbits in the current and previous years. This correlation probably results from a previously documented preference for very short vegetation strewn with small stones created by grazing and soil disturbance by Rabbits. The average number of young fledged per pair was adequate to maintain a stable population, but varied by an order of magnitude among years. Annual variation in chick survival had the largest influence on variation in overall productivity, because breeding failures at the egg stage were usually replaced. Differences in chick survival among years were not correlated with the mean rate of growth of chicks. Nest success and overall breeding success were positively correlated with a spring Rabbit count and, for nest success, there was also a negative effect of the number of Foxes culled per unit effort, which may be an index of Fox numbers. The effect of Rabbit abundance might occur because predators only seek out Stone Curlew eggs and chicks when Rabbits are scarce. It is recommended that the high Rabbit population is maintained as this appears to be beneficial to Stone Curlews breeding on seminatural grassland.

Initial effects of rabbit haemorrhagic disease on free-living rabbit (Oryctolagus cuniculus) populations in central-western New South Wales

Quarterly spotlight counts of rabbits were conducted at three sites in central-western New South Wales. These counts commenced two years before the arrival of rabbit haemorrhagic disease (RHD) in the winter of 1996. The existing data on quarterly rates of change in rabbit abundance for the three populations provided a unique opportunity to study the effects of RHD on rabbit demography. Prior to the arrival of RHD, all three populations underwent phases of sequential increase and decrease in each year. On the basis of these patterns, RHD had a variable influence on the demography of the three rabbit populations. In 1996–97, the density of two populations declined over an expected period of increase, while at the third site the density increased as expected from pre-RHD patterns. Twelve months after their failure to generate expected positive rates of increase the two affected populations had returned to the normal sequence of increases and decreases in density although still at comparatively low numbers.

Spotlight counts for assessing abundance of rabbits (Oryctolagus cuniculus L.)

We determined the precision of spotlight counts of rabbits (Oryctolagus cuniculus L.) and their accuracy as estimates of density, by making counts from a motorcycle along 17 1-km transects in the Mackenzie Basin, New Zealand. Rabbits were poisoned and density per 1-ha quadrat was measured. Precision of spotlight counts would be between 5–28% and 6–39%, using impracticably large numbers of counts, even allowing for the effects of snow and heavy rain, observer bias and number of runs per night. Spatial and unexplained variance would result in even less precise counts using 25 transects and 1–5 nights. Actual rabbit densities explained only 41% of the variance in spotlight counts. Confidence intervals of absolute rabbit densities are extremely large, especially when observed counts are high. At best, spotlight counts could be used to detect differences in actual rabbit abundance spanning an order of magnitude or more. Observed reduction in spotlight counts is likely to underestimate reduction in actual density because the spotlight count index ‘saturates’ at high rabbit density. However, spotlight counts along fixed transects before and after a control operation can be used to estimate percentage kill with acceptable precision if the kill rate is at least 80%.

Co-existence between Iberian lynx and Egyptian mongooses: estimating interaction strength by structural equation modelling and testing by an observational study.

We used path analysis to investigate the causal relationships between Iberian lynx and Egyptian mongoose track numbers, and to estimate the direct effect of the former on the latter in the Doñana area (2750 km(2) ), south-western Spain. Relative abundance of rabbits, shrub cover and protection level were also considered in the path analysis. An observational study consisting of a repeated track survey with a split-plot design was also carried out between 1990 and 1996 to independently test the results obtained by path analysis. Maximum likelihood ratio tests of the goodness-of-fit of the model to the data and other indices used all indicated that the proposed theoretical model depicting the relationships among variables was adequate. Egyptian mongooses suffered a significant direct negative effect from lynx, and rabbits and protection level positively, and significantly affected lynx track abundance; rabbits were also significantly affected by shrub cover (all these standardized partial correlation coefficients ranged from 0.34 to 0.41). Shrub cover did not directly affect either lynx or mongoose tracks. Relatively important indirect effects were found between shrubs and lynx (0.12), and between rabbits and mongooses (-0.14), and protection and mongooses (-0.17). The two latter non-intuitive indirect effects were through the lynx path, as a consequence of the negative direct influence of lynx on mongooses. The repeated track censuses confirmed that lynx presence significantly affects number of mongoose tracks. In areas without lynx, mean number of mongoose tracks were 3.6 times higher than in areas with lynx. It remains an interesting question which of several proposed hypotheses explains co-existence of both species in south-western Spain.

Long‐term study of litter size in relation to population density in rabbits (Oryctolagus cuniculus) in Lincolnshire, England

AbstractAfter the introduction of myxomatosis to the U.K. in 1953, the rabbit Oryctolagus cuniculus population crashed to less than 1% of its original size (Lloyd, 1970). Since that time the population has been slowly recovering, and reached about 20% of pre‐myxomatosis levels by 1980 (Lloyd, 1981; Trout, Tapper &amp; Harradine, 1986). Between 1980 and 1986 an index of rabbit abundance was produced from field surveys, which resulted in an estimated population growth rate of just under 1% per year but there has been no objective assessment of the changes nationally since 1986.

A Study on the Diet of Minor Grisons and a Preliminary Analysis of Their Role in the Control of Rabbits in Patagonia

Despite their wide-spread distribution and abundance, grisons (Galictis cuja) are one of the least known carnivore in the Neotropics. We studied their diet in North-western Patagonia, and evaluated their potential impact on European rabbits (Oryctolagus cuniculus). Rabbits invaded Argentina from Chile between 1945 and 1950 and have since rapidly expanded southwards along the river valleys of North-western Patagonia. We compared the diet of grisons between sites of similar environmental characteristics that differed in the abundance of rabbits by analysis of their scats. Grisons preyed primarily upon mammals (lagomorphs and cricetids), and secondarily upon birds and reptiles. They hunt almost exclusively on lagomorphs when the density of rabbits is high. This result indicates that grisons may be important predators of rabbits and therefore further studies are warranted to confirm their role in the control of rabbits in Patagonia.

Behavioral Responses of Two Predator Species to Sudden Declines in Primary Prey

Feral ferrets (Mustela furo) and cats (Felis catus) are pests in New Zealand because they carry bovine tuberculosis (Tb) and prey on native fauna. We examined their behavioral responses to large-scale poisoning of their primary prey, feral European rabbits (oryctolagus cuniculus). We monitored the movements of 70 radiocollared ferrets and 28 radiocollared cats for 2 years during pre- and posttreatment periods for 1 nontreatment (Earnscleugh) and 2 treatment (Bendigo, Grays Hills) populations in tussock grassland habitat on New Zealand's South Island. There were no changes (P > 0.05) in the mean home range size of ferrets on the Bendigo site (70 ha prepoisoning and 67 ha postpoisoning), where poisoning reduced rabbit numbers by 77%, or on the Earnscleugh site (71 ha prepoisoning and 61 ha postpoisoning), where rabbit numbers remained high. However, when rabbit numbers were reduced by 99%, ferrets on Grays Hills increased home range from 85 to 230 ha (P < 0.05), and their mean distance from range center increased from 475 to 993 m (P < 0.001). While most ferrets at Grays Hills remained resident, the proportion of mobile ferrets increased from 1 of 25 to 6 of 18 (P = 0.015). For cats, treatment effects were less clear because sample sizes were low and data were highly variable. However, 3 adult cats at Grays Hills dispersed up to 9.2 km from range centers after rabbit numbers were reduced by 99%. No obvious behavioral changes of predators were observed where rabbit declines were less pronounced or where rabbit abundance remained high. This observation suggests that large changes in predator movements occur only after very large disturbances to their primary prey, but there was insufficient replication of treatments to separate treatment effects from site effects. Nevertheless, our qualitative results indicate that very large reductions in rabbit populations in tussock grassland are likely to cause a small number of predators to disperse into adjacent areas. In the absence of a clear understanding of the role of ferrets and cats in the epidemiology of bovine Tb, and of their effects on native fauna, the implications of this induced dispersal are unknown. Intuitively, however, any consequences are likely to be adverse.

Interactive Effects of Prey and Weather on Golden Eagle Reproduction

1. The reproduction of the golden eagle Aquila chrysaetos was studied in southwestern Idaho for 23 years, and the relationship between eagle reproduction and jackrabbit Lepus californicus abundance, weather factors, and their interactions, was modelled using general linear models. Backward elimination procedures were used to arrive at parsimonious models. 2. The number of golden eagle pairs occupying nesting territories each year showed a significant decline through time that was unrelated to either annual rabbit abundance or winter severity. However, eagle hatching dates were significantly related to both winter severity and jackrabbit abundance. Eagles hatched earlier when jackrabbits were abundant, and they hatched later after severe winters. 3. Jackrabbit abundance influenced the proportion of pairs that laid eggs, the proportion of pairs that were successful, mean brood size at fledging, and the number of young fledged per pair. Weather interacted with prey to influence eagle reproductive rates. 4. Both jackrabbit abundance and winter severity were important in predicting the percentage of eagle pairs that laid eggs. Percentage laying was related positively to jackrabbit abundance and inversely related to winter severity. 5. The variables most useful in predicting percentage of laying pairs successful were rabbit abundance and the number of extremely hot days during brood-rearing. The number of hot days and rabbit abundance were also significant in a model predicting eagle brood size at fledging. Both success and brood size were positively related to jackrabbit abundance and inversely related to the frequency of hot days in spring. 6. Eagle reproduction was limited by rabbit abundance during approximately two-thirds of the years studied. Weather influenced how severely eagle reproduction declined in those years. 7. This study demonstrates that prey and weather can interact to limit a large raptor population's productivity. Smaller raptors could be affected more strongly, especially in colder or wetter climates.

Control of Feral Cats for Nature Conservation. II. Population Reduction by Poisoning

A feral cat population was substantially reduced by poisoning at a semi-arid site in Western Australia. The control programme was designed to protect two species of endangered native mammals that had recently been reintroduced to the site. Feral cats were poisoned with carcasses of laboratory mice, each impregnated with 4.5 mg of sodium monofluoroacetate (1080). Baits were placed at 100-m intervals along the track system each night for four consecutive nights. Kill rates were assessed by monitoring survival of radio- collared cats and by spotlight counts of cats before and after baiting. All radio-collared cats were killed and there was a 74% reduction in spotlight counts of cats after baiting. Bait removal varied with the abundance of rabbits, the primary prey item for cats in this area. Effectiveness of control operations against feral cats is maximised by baiting at times of low prey abundance. Monitoring the changing abundance of the primary prey species provides important information for timing control operations against feral cats.

Day‐time transect counts to measure relative abundance of rabbits (Oryctolagus cuniculus)

Day‐time transect counts to measure relative abundance of rabbits (<i>Oryctolagus cuniculus</i>)

Habitat Suitability Study for the Conservation of the Volcano Rabbit (Romerolagus diazi)

The endangered Mexican volcano rabbit (Romerolagus diazi)-habitat relationship was investigated. Data, obtained from 137 sampling units in 14 patches of the geographical distribution areas of the rabbit, included information on floristic composition, vegetation structure, terrain characteristics and human activities. The abundance of the volcano rabbit was measured in 685 subsampling units by pellet-counts and estimations of pellet-coverage. Two questions have been addressed in this paper: what is a good indicator of habitat type and which are the habitat factors that explain best the distribution of the volcano rabbit? Thirteen plant communities were identified. Terrain and landscape units were distinguished through aerial photograph interpretation and were verified in the field. By means of classical (parametric and non-parametric) and multivariate (Canonical Correspondence Analysis) statistical analyses, the most suitable, suitable and unsuitable habitat classes were detected. The results indicated that plant communities (F = 4,14; P < 0.0001) and landscape units (F = 7,29; P < 0.001) were adequate levels to distinguish habitat types for the rabbit. Plant communities of Festuca tolucensis and Trisetum altijugum-Festuca tolucensis attained the largest abundance of rabbits, followed by the communities Muhlenbergia quadridentata-Pinus hartwegii, Festuca tolucensis-Pinus hartwegii and Pinus sp.-Alnus firmifolia. The abundances of the volcano rabbit in the remaining plant communities were significantly less than in the communities mentioned above. These results suggest that the volcano rabbit shows strong preferences for subalpine habitat types. Soil moisture (r = -0.840), altitude (r = -0.756), grazing (r = -0.423) and burning (r = 0.494) correlated significantly with the distribution and abundance of the volcano rabbit. These results are discussed in light of their role in the conservation of the volcano rabbit.

Effectiveness and Cost-Efficiency of Control of the Wild Rabbit, Oryctolagus Cuniculus (L.), By Combinations of Poisoning, Ripping, Fumigation and Maintenance Fumigation.

An experiment compared effectiveness, cost and cost-efficiency of factorial combinations of the four commonly used methods of rabbit control on grazing properties in the Southern Tablelands of eastern Australia. Sixteen different treatment combinations were applied to 32 sites. The treatments comprised initial control, applied over four months, followed by repeated maintenance control on half the replicates, applied after intervals of 2,6 and 12 months. Initial control comprised no treatment, or poisoning (P) with sodium monofluoroacetate (1080), or warren-ripping (R), or chloropicrin pressure fumigation (F), or combinations of these (P+R, P+F, R+F, P+R+F). Maintenance control consisted of phosphine-diffusion fumigation (M). Indices of rabbit abundance were compared one month before treatments were implemented. Treatment effects were assessed one month after completion of the initial control, and one and 5-6 months after the three maintenance controls, and additionally nine months after the second maintenance control. Control combinations that were highly effective and cost-efficient included both warren-ripping and maintenance treatment. Poisoning prior to warren-ripping, or fumigating subsequently, or both, improved effectiveness and cost-efficiency. Warren-ripping interacted positively with one or more subsequent fumigations, improving effectiveness and cost-efficiency non-additively. Control combinations that excluded warren-ripping were ineffective and cost-inefficient, and one combination interacted negatively. Single treatments of poisoning or fumigation were cost-inefficient, allowing rabbits to recolonise rapidly to densities higher than original. Only multiple combination treatments or repeated applications were highly effective and cost-efficient; single applications of any method were inefficient and costly. The most effective and cost-efficient combination comprised the maximum six applications including ripping and maintenance treatment, namely P+R+F+M. The high effort and expenditure on the initial control resulted in high effectiveness and cost-efficiency, which maintenance control sustained at low cost. Maintenance treatments sustained or achieved effective control of rabbits; the cost of maintenance treatments halved on each repetition.