Optimizing the ratio of captures to trapping effort in a black rat Rattus rattus control programme in New Zealand

The ratio of captures to unit effort is an important cost/benefit measure for volunteer pest control programmes. We describe an experiment designed to investigate the use of pre-feeding and trap pulsing as possible means of increasing this ratio. In 20 traps locked-open and pre-fed with non-toxic pellets for five days, the same number of black rats was caught over the next 5 days as in 20 non pre-fed traps set for the whole 10 days (32 rats each). Allowing for successful traps being unavailable for an average of half a night each, the capture rate in the pre-fed traps was 47% over five days, more than double that in the non pre-fed traps set for twice as long (total 19% in 10 days)

Anticipatory responses to pulsed resources: An introduction

Vigorous exchange of ideas is an essential part of the business of science. What makes that interaction so much more interesting than ordinary conversation is that, in science, ideas always have to be based on documented observation of the real world.No one disputes that requirement, yet it does not automatically ensure agreement, even when all parties are observing the same bits of the same world. That is because what we see in front of our eyes is powerfully influenced by what is behind them. Observations are never free of assumptions, which in turn are never independent of previous knowledge and experience

Swimming capabilities of stoats and the threat to inshore sanctuaries

Stoats (Mustela erminea) are small carnivorous mammals which were introduced into New Zealand in the late 19th century, and have now become widespread invasive pests. Stoats have long been known to be capable of swimming to islands 1-1.5 km offshore. Islands further out have usually been assumed to be safe from invasion, therefore routine stoat monitoring on them has been considered un-necessary. Recent incursions, including a stoat found on Rangitoto Island (3 km offshore) in 2010, and another which was deduced to have reached Kapiti (5 km offshore) in 2009, along with distribution modelling and genetic studies, strongly support the proposition that stoats can swim much further than 1.5 km. Acceptance of this hypothesis depends on estimating the probability that such small animals could indeed swim so far unaided. This paper reports the results of a project designed to assist this debate by recording the paddling action, speed and minimal endurance of nine stoats observed (once each) swimming against an endless current in a flume at the Aquatic Research Centre, University of Waikato. Four of the five males and two of the four females could hold a position for at least five minutes against the maximum current available, averaging 1.36 ± 0.336 km/h. In steady swimming against a current of c. 1 km/hr, they all used a rapid quadripedal paddling action (averaging 250 strokes/min, stronger with the spread forepaws). Four of the nine swam strongly for >1 h, including one female who covered 1.8 km in nearly 2 h non- stop. Results from such artificial conditions cannot be conclusive, but support suggestions that wild stoats could indeed swim much further than 1.5 km, hence we conclude that the “risk zone” for stoat reinvasions of inshore islands has been seriously under-estimated

Water stress impacts on bacterial carbon monoxide oxidation on recent volcanic deposits

Water availability oscillates dramatically on young volcanic deposits, and may control the distribution and activity of microbes during early stages of biological succession. Carbon monoxide (CO)-oxidizing bacteria are among the pioneering colonists on volcanic deposits and are subjected to these water stresses. We report here the effects of water potential on CO-oxidizing bacteria in unvegetated (bare) and vegetated (canopy) sites on a 1959 volcanic deposit on Kilauea Volcano (Hawai\u27i). Time course measurements of water potential showed that average water potentials in the surface layer (0-1 cm) of canopy soil remained between 0.1 and 0 MPa, whereas dramatic diurnal oscillations (for example, between 60 and 0 MPa) occur in bare site surface cinders. During a moderate drying event in situ (1.7 to 0 MPa), atmospheric CO consumption by intact bare site cores decreased 2.7-fold. For bare and canopy surface samples, maximum potential CO oxidation rates decreased 40 and 60%, respectively, when water potentials were lowered from 0 to 1.5 MPa in the laboratory. These observations indicated that CO oxidation is moderately sensitive to changes in water potential. Additional analyses showed that CO oxidation resumes within a few hours of rehydration, even after desiccation at 150 MPa for 63 days. Samples from both sites exposed to multiple cycles of drying and rewetting (80 to 0 MPa), lost significant activity after the first cycle, but not after subsequent cycles. Similar responses of CO oxidation in both sites suggested that active CO-oxidizing communities in bare and canopy sites do not express differential adaptations to water stress. © 2009 International Society for Microbial Ecology All rights reserved

The phylogenetic distribution and ecological role of carbon monoxide oxidation in the genus Burkholderia

Burkholderia is a physiologically and ecologically diverse genus that occurs commonly in assemblages of soil and rhizosphere bacteria. Although Burkholderia is known for its heterotrophic versatility, we demonstrate that 14 distinct environmental isolates oxidized carbon monoxide (CO) and possessed the gene encoding the catalytic subunit of form I CO dehydrogenase (coxL). DNA from a Burkholderia isolate obtained from a passalid beetle also contained coxL as do the genomic sequences of species H160 and Ch1-1. Isolates were able to consume CO at concentrations ranging from 100 ppm (vol/vol) to sub-ambient (\u3c 60 ppb (vol/vol)). High concentrations of pyruvate inhibited CO uptake (\u3e 2.5 mM), but mixotrophic consumption of CO and pyruvate occurred when initial pyruvate concentrations were lower (c. 400 μM). With the exception of an isolate most closely related to Burkholderia cepacia, all CO-oxidizing isolates examined were members of a nonpathogenic clade and were most closely related to Burkholderia species, B. caledonica, B. fungorum, B. oxiphila, B. mimosarum, B. nodosa, B. sacchari, B. bryophila, B. ferrariae, B. ginsengesoli, and B. unamae. However, none of these type strains oxidized CO or contained coxL based on results from PCR analyses. Collectively, these results demonstrate that the presence of CO oxidation within members of the Burkholderia genus is variable but it is most commonly found among rhizosphere inhabitants that are not closely related to B. cepacia. © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved 79 1 January 2012 10.1111/j.1574-6941.2011.01206.x Research Article Research Articles © 2011 Federation of European Microbiological Societies. Published by Blackwell Publishing Ltd. All rights reserved

Volcanic soils as sources of novel CO-oxidizing Paraburkholderia and Burkholderia: Paraburkholderia hiiakae sp. nov., Paraburkholderia metrosideri sp. nov., Paraburkholderia paradisi sp. nov., Paraburkholderia peleae sp. nov., and Burkholderia alpina sp. nov. a member of the Burkholderia cepacia complex

© 2017 Weber and King. Previous studies showed that members of the Burkholderiales were important in the succession of aerobic, molybdenum-dependent CO oxidizing-bacteria on volcanic soils. During these studies, four isolates were obtained from Kilauea Volcano (Hawai\u27i, USA); one strain was isolated from Pico de Orizaba (Mexico) during a separate study. Based on 16S rRNA gene sequence similarities, the Pico de Orizaba isolate and the isolates from Kilauea Volcano were provisionally assigned to the genera Burkholderia and Paraburkholderia, respectively. Each of the isolates possessed a form I coxL gene that encoded the catalytic subunit of carbon monoxide dehydrogenase (CODH); none of the most closely related type strains possessed coxL or oxidized CO. Genome sequences for Paraburkholderia type strains facilitated an analysis of 16S rRNA gene sequence similarities and average nucleotide identities (ANI). ANI did not exceed 95% (the recommended cutoff for species differentiation) for any of the pairwise comparisons among 27 reference strains related to the new isolates. However, since the highest 16S rRNA gene sequence similarity among this set of reference strains was 98.93%, DNA-DNA hybridizations (DDH) were performed for two isolates whose 16S rRNA gene sequence similarities with their nearest phylogenetic neighbors were 98.96 and 99.11%. In both cases DDH values were \u3c 16%. Based on multiple variables, four of the isolates represent novel species within the Paraburkholderia: Paraburkholderia hiiakae sp. nov. (type strain I2T = DSM 28029T = LMG 27952T); Paraburkholderia paradisi sp. nov. (type strain WAT = DSM 28027T = LMG 27949T); Paraburkholderia peleae sp. nov. (type strain PP52-1T = DSM 28028T = LMG 27950T); and Paraburkholderia metrosideri sp. nov. (type strain DNBP6-1T = DSM 28030T = LMG 28140T). The remaining isolate represents the first CO-oxidizing member of the Burkholderia cepacia complex: Burkholderia alpina sp. nov. (type strain PO-04-17-38T = DSM 28031T = LMG 28138T)

Physiological, ecological, and phylogenetic characterization of Stappia, a marine CO-oxidizing bacterial genus

Bacteria play a major role in marine CO cycling, yet very little is known about the microbes involved. Thirteen CO-oxidizing Stappia isolates obtained from existing cultures, macroalgae, or surf samples representing geographically and ecologically diverse habitats were characterized using biochemical, physiological, and phylogenetic approaches. All isolates were aerobic chemoorganotrophs that oxidized CO at elevated (1,000 ppm) and ambient-to-subambient concentrations (\u3c0.3 ppm). All contained the form I (OMP) coxL gene for aerobic CO dehydrogenase and also the form II (BMS) putative coxL gene. In addition, some strains possessed cbbL, the large subunit gene for ribulose-1,5-bisphosphate carboxylase/oxygenase, suggesting the possibility of lithotrophic or mixotrophic metabolism. All isolates used a wide range of sugars, organic acids, amino acids, and aromatics for growth and grew at salinities from 5 to 45 ppt. All but one isolate denitrified or respired nitrate. Phylogenetic analyses based on 16S rRNA gene sequences indicated that several isolates could not be distinguished from Stappia aggregata and contributed to a widely distributed species complex. Four isolates (of strains GA15, HI, MIO, and M4) were phylogenetically distinct from validly described Stappia species and closely related genera (e.g., Ahrensia, Pannonibacter, Pseudovibrio, and Roseibium). Substrate utilization profiles, enzymatic activity, and membrane lipid composition further distinguished these isolates and supported their designations as new Stappia species. The observed metabolic versatility of Stappia likely accounts for its cosmopolitan distribution and its ability to contribute to CO cycling as well as other important biogeochemical cycles. Copyright © 2007, American Society for Microbiology. All Rights Reserved

Interactions between bacterial carbon monoxide and hydrogen consumption and plant development on recent volcanic deposits

Patterns of microbial colonization and interactions between microbial processes and vascular plants on volcanic deposits have received little attention. Previous reports have shown that atmospheric CO and hydrogen contribute significantly to microbial metabolism on Kilauea volcano (Hawaii) deposits with varied ages and successional development. Relationships between CO oxidation and plant communities were not clear, however, since deposit age and vegetation status covaried. To determine plant-microbe interactions in deposits of uniform ages, CO and hydrogen dynamics have been assayed for unvegetated tephra on a 1959 deposit at Puu Puai (PP-bare), at the edge of tree islands within the PP deposit (PP-edge) and within PP tree islands (PP-canopy). Similar assays have been conducted for vegetated and unvegetated sites on a 1969 Mauna Ulu (MU) lava flow. Net in situ atmospheric CO uptake was highest at PP-edge and PP-bare sites (2.2±0.5 and 1.3±0.1mg COm2day 1, respectively), and least for PP-canopy (3.2±0.9mg COm 2day1, net emission). Respiration rates, microbial biomass and maximum CO uptake potential showed an opposing pattern. Comparisons of atmospheric CO uptake and CO 2 production rates indicate that CO contributes significantly to microbial metabolism in PP-bare and MU-unvegetated sites, but negligibly where vegetation is well developed. Nonetheless, maximum potential CO uptake rates indicate that CO oxidizer populations increase with increasing plant biomass and consume CO actively. Some of these CO oxidizers may contribute to elevated nitrogen fixation rates (acetylene reduction) measured within tree islands, and thus, support plant successional development. © 2008 International Society for Microbial Ecology. All rights reserved

Pandora’s box down-under: origins and numbers of mustelids transported to New Zealand for biological control of rabbits

This paper describes one of the world’s first large-scale experiments in biological control of a major vertebrate pest of agriculture, which was tried in New Zealand during the second half of the nineteenth century. Starting from the late 1860s, pasture damage in Southland and Otago by European rabbits was causing serious reductions in productivity of sheep (wool clip and lambing percentages) associated with malnutrition of the breeding ewes, and a consequent decline in the value of pastoral land. In response, and despite repeated local and international warnings, ferrets, stoats and weasels (Mustela furo, M. erminea and M. nivalis) were liberated on the worst of the rabbit-infested pastures. They were perceived as the ‘natural enemies of the rabbit’ but (unlike foxes) too small to threaten lambs. Over the 50 years after 1870, upwards of 75,000 ferrets, most imported from Australia or locally bred, were released in the South Island. Over the decade 1883–1892, at least 7838 stoats and weasels arrived from Britain. At least 25 shipments are known, with an average of only 10% mortality per shipment. Of the 3585 animals listed by species, 73% were weasels. The total cost of the ferret programme cannot now be estimated; that of stoats and weasels alone was at least £5441, probably twice that, or >$NZ 1–2 million in today’s money. Mustelids (and cats) killed many young rabbits, which was helpful because rates of change in rabbit populations are sensitive to variations in juvenile mortality, but in the most rabbit-prone semi-arid lands, mustelids could not remove enough rabbits to prevent the continuing damage to sheep pastures. The era of deliberate introductions of mustelids to control rabbits in New Zealand was short, expensive, and unsuccessful