Sodium fluoroacetate (1080) has been used as an aerially distributed toxin against mammalian pests in New Zealand since the 1950s. Although its use for rabbit (Oryctolagus cuniculus) control ceased temporarily after the illegal release of rabbit haemorrhagic disease virus (RHDV) in 1997, there has been a recent resurgence in the use of aerial baiting with 1080 to control rabbits as the efficacy of RHDV has fallen. Current practices for rabbit control using 1080 have changed little since the 1980s, with high sowing rates and low toxin loadings commonplace. The lack of ongoing development in baiting practices for rabbit control contrasts sharply with continued improvements in the aerial 1080 baiting practices for brushtail possums (Trichosurus vulpecula) in New Zealand, such as a shift to a comparatively high 1080 loading and using much lower application rates of prefeed and toxic bait. These modifications have resulted in an overall reduction in the amount of toxin used for possum control. The disparity in these two approaches prompted a formal review of the rationale on which the current 1080 baiting practices for rabbits are based. Two issues emerged strongly. First, the current low toxin loading used (0.02–0.04% 1080 in bait) is not based on experimental optimisation in New Zealand but, rather, on research conducted several decades earlier in Australia. Second, despite long-standing concerns about the quality of carrot bait used in New Zealand, current bait manufacturing and distribution practices still produce large numbers of small sublethal fragments. Thus, the current New Zealand practice of multiple prefeeds and very high sowing rates of bait with a low 1080 loading used against rabbits seems to have resulted from the need to compensate for the low toxic loading and poor quality control of the bait (carrots). We, therefore, suggest that there is considerable potential to improve current aerial 1080 baiting practices for controlling rabbits in New Zealand. More generally, these findings also help illustrate that ‘best’ pest-management practice may sometimes be based on pragmatic solutions aimed at overcoming unrecognised internal constraints that are in fact avoidable. Refining and modernising vertebrate pest-control programs, so that they better meet efficacy requirements and contemporary public expectations, therefore requires understanding not just that a solution works, but also how it works.

Context . Significant efforts have been made in Michigan, USA, to reduce the prevalence of bovine tuberculosis (TB) in free-ranging white-tailed deer (Odocoileus virginianus) over the past 15 years. Since 2002, however, prevalence has changed little, prompting the need for new control strategies.

Aims. . In January–March of 2007 and 2008, a trap–test–cull project was conducted on an 11 000-ha property in the north-eastern Lower Peninsula of Michigan. The objectives were to assess the feasibility of live-trapping and testing white-tailed deer for TB as a means for targeted removal and estimate the cost of this effort.

Methods. . Live-trapped deer were ear-tagged and a blood sample was drawn for use with the CervidTB STAT-PAK (commonly called Rapid Test) for TB diagnosis in the field. Deer testing negative were released, whereas deer testing positive were euthanised to confirm blood-test results via bacterial culture.

Key results. . In all, 762 (741 with known sex and age) individual deer were captured and tested for TB. Adults comprised 59% (437 of 741) of the captures. Eight (1.8%) adults were positive on the blood test; six of eight (1.4% of adults) were confirmed TB positive via bacterial culture. Estimated TB prevalence in the present study was 2.5% (adjusted for Rapid Test sensitivity of 56%), being lower than what would be expected on the basis of routine hunter-harvest surveillance for this site which has yielded prevalence rates from 3.4% to 4.8%. Results demonstrated the ability to trap and test a substantial number of deer given high deer densities (16–20 deer per km²), availability of traps and abundant workers. The 2-year project cost a total of ∼US$228 000, or US$38 000 per culture-positive animal.

Conclusions. . Because of the cost and effort involved, a project such as the present one applied to Michigan’s larger TB-management area (148 018 ha) is not feasible.

Implications. . If the efficiency and effectiveness of a trap–test–cull project could be improved by vaccinating test-negative animals, should a vaccine be approved for use in free-ranging white-tailed deer, a trap–test–cull project applied on a scale similar to the present study may prove beneficial by possibly reducing disease transmission, in addition to removing TB-positive animals.

Context. Calomys musculinus (Cricetidae, Sigmodontinae) is a small rodent species widely distributed in Argentina and particularly abundant in agroecosystems of the Pampean region, where it is known to select border habitats over cropfields.

Aims. The aim of the present research was to assess habitat use by C. musculinus in cropfield borders. Assuming that the number of rodent captures in each border reflects the intensity of use, we intended to identify the habitat characteristics that would account for abundance differences among borders.

Methods. Seasonal trapping sessions were carried out in borders of the rural zone of Chucul, Córdoba. Environmental variables were registered from both field surveys and remote-sensing imagery. Generalised linear models were used to identify the habitat variables associated with C. musculinus habitat use.

Key results. General fit of the models was fairly good; spring, summer and autumn models explained more than 55% of the variation in C. musculinus abundance among borders. Individual plant species were significant predictors of C. musculinus abundance, but they varied with seasons, whereas tree cover and border width were significant predictors in most seasons studied. In general, rodent abundance was positively associated with peanut and maize crops or maize stubbles and negatively related to soybean or its stubbles. In the coldest seasons, rodent abundance increased with increasing land-surface temperature of the border.

Conclusions. Border use by C. musculinus appeared to respond to differences in border quality, which seems to be more affected by those environmental characteristics that entail a reduction of the predatory risk rather than by those that involve food supply. Crop-fields may partially afford C. musculinus food requirements.

Implications. Because C. musculinus is the natural reservoir of a zoonotic agent, the identification of the habitat characteristics affecting rodent population numbers in borders may be of crucial importance for the implementation of ecologically based rodent-management strategies aimed at reducing human–rodent contacts. We suggest that wide borders, particularly those contiguous to maize and peanut cropfields, should be understood as priority sites for the implementation of specific control actions.

Context . Management of grazing wildlife on private land in Tasmania is a contentious issue for landowners, animal-welfare groups and the Tasmanian Government. Wildlife species known to graze pasture include Tasmanian pademelon (Thylogale billardierii), Bennett’s wallaby (Macropus rufogriseus rufogriseus), forester kangaroo (Macropus giganteus), brushtail possum (Trichosurus vulpecula) and fallow deer (Dama dama). Understanding the spatio-temporal patterns of wildlife grazing is important when considering wildlife-control options to mitigate pasture loss; however, limited research has been undertaken.

Aims . To quantify the impact of wildlife grazing on pasture production and to assess the spatial and temporal pasture biomass loss from an established pasture; to investigate the effect of protecting pastures from wildlife grazing on species composition of an existing perennial pasture; to determine whether wildlife grazing contributes to a decline in the composition of improved pasture species over time and an increase in-ground cover of less desirable grasses and broadleaf weeds; and to examine whether protecting pastures from wildlife grazing could increase ground cover.

Methods . Pasture biomass loss to wildlife grazing was determined by a paired exclusion-cage method over a 26-month period from February 2008 to April 2010. A quantitative pasture model was used to simulate pasture growth at the study site. Changes in the botanical composition of the sward in response to wildlife grazing were determined by hand-separation, drying and weighing of harvested material, and also by visual estimation of the ground cover of individual plant species. A wildlife faecal-pellet survey was used to develop an index of wildlife feeding activity.

Key results . Pasture loss to wildlife grazing varied spatially and temporally. Pasture loss decreased with increasing distance from the edge of cover vegetation. The proportion of pasture lost increased during periods of slow pasture growth. Visual estimates of ground cover showed that grazing by wildlife resulted in an increase in bare ground in unprotected swards, whereas protection from grazing resulted in an increase in production of perennial and annual species, as determined by hand-separation of harvested material, and a decrease in bare ground as determined by visual estimate. Faecal-pellet surveys were found to be strongly correlated with pasture biomass losses.

Conclusions . The proportion of pasture loss to wildlife grazing was found to be influenced by distance from native vegetation and also by pasture availability, which was seasonal. Wildlife can alter the composition of pastures by reducing the ground cover and yield of improved grasses. Continual grazing of pastures by wildlife in addition to rotational sheep grazing may increase the amount of bare ground.

Implications . Wildlife-control methods need to be carefully chosen if the intended benefits of alleviating pasture biomass losses are to be achieved. Quantifying the loss of pasture is important because it enables the extent and significance of losses to be determined and may inform decisions about the most appropriate wildlife control measures to adopt. Controlling wildlife during periods of slow pasture growth may be important in preventing damage and yield loss of plant species actively growing during these times. Failure to control wildlife may result in a decrease in the composition of desirable plant species.

Context. The Australian sea lion population at Seal Bay Conservation Park, South Australia, was estimated to be declining at a rate of 1.14% per breeding season, on the basis of maximum counts of live pups in each of 13 breeding seasons (Shaughnessy et al. 2006). The reliability of the pup-production estimates used to identify this decline is uncertain.

Aims. Our aims were to obtain representative and repeatable estimates of pup production and to assess the current rate of decline.

Methods. We compared four estimates of pup abundance over five breeding seasons (2002–03, 2004, 2005–06, 2007, 2008–09), including the count of cumulative new births, the maximum live-pup count, the number of pups given passive integrated transponder (PIT) tags, and mark–recapture methods using the Petersen estimate.

Key results. A total of 90% of pup births occurred over a mean of 124 days (s.d. = 14). Final estimates of pup production (from the largest of the four estimation methods used) in the five seasons were 227 (CL 221–239), 288 (CL 273–302), 219 (NA), 260 (CL 254–272) and 268 (CL 268–269). The average estimate of pup mortality was 28.6% (s.d. = 6.3%). The decline in the population at Seal Bay over 17 breeding seasons on the basis of maximum counts of live pups was 0.51% per year or 0.76% per breeding season. However, this trend was not based on best estimates of pup production. On the basis of final estimates for the last five breeding seasons, there is no declining trend.

Conclusions. The count of cumulative new births was the most reliable measure of pup production; the Petersen mark–recapture estimate provided a check for accuracy and confidence limits about the estimate.

Implications. The actual rate of change and the expected trajectory of the Seal Bay population remain uncertain. Ongoing monitoring is a priority for this site, using the reliable methods of estimating pup production identified in the present study.

Context . In many parts of the world, artificial refuges (ARs) are increasingly used to survey different kinds of herpetofauna. Despite gaining popularity, the merit of using ARs compared with standardised active searches remains poorly known, as does their application in regions that support species exhibiting varied life-form strategies.

Aims . We examined the effectiveness of using two survey methods, active searches and ARs (corrugated steel, roof tiles and three different timber refuges), to detect herpetofauna in a range of eucalypt-woodland communities in south-eastern Australia.

Methods . We collected count data over a 12-year period from three independent long-term biodiversity monitoring programs in southern New South Wales. We used generalised linear models to compare detection probabilities among survey methods (active searches versus ARs) and among ARs, for each study area.

Key results . In all study areas, active searches detected the highest mean species richness per site. However, both methods provided complimentary species, thereby maximising species inventory at a regional scale. Species more likely to be detected in active searches included diurnally active, terrestrial and arboreal heliotherms, whereas species detected more frequently using ARs included nocturnal thigmotherms.

Conclusions . A combination of active searches and AR types is required to provide regional-scale representative reptile assemblages, although more than five consecutive surveys may be needed before species accumulation curves reach plateaux. In future studies, we recommend using stacks of corrugated steel to detect heliothermic Scincidae and arboreal Gekkonidae, roof tiles to detect thigmothermic Pygopodidae and railway sleepers to detect cryptozoic Elapidae and tunnel-dwelling Gekkonidae.

Implications . Using a combination of ARs and active searches will increase the chance of detecting both common and cryptic species and deploying corrugated steel provides a cost-effective method for surveying reptiles in long-term studies.

Context . Variable demographic rates can manifest themselves between habitat types in the form of source–sink dynamics where populations in sink habitats would not exist without the addition of migrants from source habitats.

Aims . Arctic ground squirrels (Urocitellus parryii pleisus (Osgood, 1900)) occupy a large geographic area in northern Canada and live in a variety of habitat types, including boreal forest, low-elevation meadows and alpine meadows, providing an opportunity to investigate the possible existence of source–sink dynamics.

Methods . We hypothesised that arctic ground squirrels in the south-western Yukon exhibit demographic characteristics indicative of source–sink dynamics. Boreal forest habitat could be a sink in spite of previous high squirrel densities, whereas meadows could be a source. We investigated this by mark–recapture live-trapping and radio-telemetry.

Key Results . In the boreal forest in the Kluane region, we found reduced recruitment, reduced population growth rates (λ), and reduced survivorship for radio-collared individuals that moved from low-elevation meadows into the boreal forest. There was no evidence from radio-collared juveniles of dispersal from high-density ground squirrel populations in alpine meadows down into boreal forest.

Conclusions . Boreal forest is a sink habitat for arctic ground squirrels. Source–sink dynamics observed between low-elevation meadow and boreal forest habitats appear to result from increased predation pressure in the boreal forest. The result has been a near extirpation of boreal forest arctic ground squirrels in the Kluane region since 1998.

Implications . Because the source areas of low-elevation meadows occupy only 7–9% of the lowland habitat, recolonisation of boreal forest sites has been very slow. Whereas alpine populations remain high in 2011, boreal forest populations remain near zero. Alpine populations do not appear to be a source for the boreal forest.

Context. Ungulates have been widely introduced in multiple ecosystems throughout the world due to their value as food and for sport hunting. The identification of foraging preferences of exotic and native ungulates living in sympatry is, therefore, becoming increasingly important in order to assess potential impacts of introduced animals on the host ecosystem.

Aims. To describe species-specific foraging strategies and infer resource selection overlap between native and exotic ungulates.

Methods. We compared the trophic ecology of three sympatric ungulate species living in a Mediterranean landscape: the native Iberian red deer Cervus elaphus hispanicus, and two exotic bovids, the European mouflon Ovis orientalis musimon and the aoudad Ammotragus lervia. We simultaneously determined herbivore diet through analyses of botanical content in faeces and assessed the nutritional content of these diets.

Key results. Higher selection of shrubs by deer was sustained throughout the year, while bovids showed seasonal shifts in forage selection. Both bovids displayed a selective dietary strategy directed towards a higher overall nutritional quality than that of deer. Divergent exploitation patterns between the studied cervid and bovids might be related to body mass and physiological adaptations to overcome secondary defence compounds of shrubs, and were largely affected by seasonal changes in the nutritional value of available vegetation. Ecological theory suggests that diet overlap should be greater between similar-sized species. Indeed, both exotics showed similar, sometimes overlapping, dietary patterns that could lead to potential competition in the use of resources. Native red deer preferences only showed some overlap with those of exotic mouflon under constrained summer conditions.

Conclusions. Dietary overlap between deer and mouflon and between aoudad and mouflon during limiting summer conditions could entail a potential competitive interaction under more even densities of the study species, since a concurrent habitat overlap between those pairs of species has previously been reported.

Implications. The outcomes of our study suggest the need for an integration of habitat and ungulate management. Management actions in Mediterranean rangelands should be directed towards protecting habitat conditions so that biodiversity is enhanced along with the presence of sustainable communities of large herbivores. Management directed towards ungulates should maintain moderate stocking rates and monitor and control introduced and native populations.