Abstract Globally, cats are a common companion animal. Allowing companion cats to roam away from home can have negative impacts on native wildlife and cat welfare. A more contained cat lifestyle can limit the detrimental impacts of roaming; however, this continues to be an uncommon choice for cat owners in many countries. Communication strategies that focus on welfare benefits for cats have successfully motivated some owners to prevent their cats from roaming. However, little is known about other factors influencing owners' decisions about roaming, such as the owner–cat relationship and their cat's membership in the local community. We conducted five focus groups with 31 cat owners in Aotearoa New Zealand to understand these factors. Using thematic analysis, we identified three major themes that describe how owners view the impacts of cat containment on their relationship with their cat/s. First, finding a balance between enabling and restricting choices to ensure the cat's welfare is at the heart of the owner–cat relationship. Critically, the cat's choice to repeatedly return home reaffirms the owner–cat relationship. Second, striking the right balance in the provision of choice and ensuring welfare are contingent on the cat's characteristics. Owners providing their cat/s with the choice to leave home are perceived to be positively associated with enabling their freedom, independence and curiosity. Third, owners perceived cats to belong in many spaces occupied by humans outside of their property, despite most participants living near populations of significant threatened species. The choice to allow a cat to roam from home impacts cat welfare, the owner–cat relationship and membership in the local cat, human and wildlife community. Efforts to facilitate the shift to a contained cat lifestyle need to help owners provide choices for their cats that will meet their welfare needs and foster the owner–cat relationship. Locally relevant strategies that consider the owners' views as members of their community will likely be more successful. Read the free Plain Language Summary for this article on the Journal blog.

Cat ownership is increasing globally, representing a growing threat to urban wildlife. Although some cities have policies and strategies for managing owned cats, the companionship value placed on cats makes such management contentious. Prioritizing cat management in urban residential zones adjacent to large significant ecological areas (SEAs; areas designated on the basis of representativeness, threat status or rarity, diversity, connectedness, or uniqueness) could maximize return on management effort. Residents in these areas may place a relatively higher value on nature than residents in suburbs with minimal or no SEAs, and therefore may be comparatively more likely to perceive cats' wildlife impacts as important. We used a quantitative survey to compare SEA and non-SEA suburbs' residents' attitudes towards cat impacts and management in Tāmaki Makaurau-Auckland, Aotearoa-New Zealand. Participants were asked to rate the importance of different feral and owned cat impacts, the importance of feral-cat control in different locations, and various ownership behaviors in terms of acceptability and best practice. SEA suburb residents placed more importance on wildlife predation impacts of feral cats and were more likely to regard 24-h cat confinement as best practice than non-SEA suburb residents. However, we also found that cat ownership and youth were negatively associated with perception of cat impacts, and owners were less likely to accept belled collars and cat confinement than nonowners. Therefore, although targeting SEA adjacent areas for cat management holds promise for reducing resident contention, proximity to such areas is a relatively minor influence for cat owners.

In wildlife ecology and biosecurity, dogs have proved successful in species-specific detection across a range of taxa including vertebrates, invertebrates and weeds. Detector dogs can also have huge value in positively engaging the public with biosecurity issues. While dogs do not appear to have been used to detect microbes in ecological contexts, they have been used successfully to detect plant pathogens in crops as well as human pathogens or diseases, both in samples of bodily fluids or breath and within built environments. However there are few examples of detector dog programmes which have tested for the ability to discriminate among closely related microbial taxa. If dogs can successfully target plant pathogens within complex forest environments, they could offer relatively cheap real-time diagnosis with considerable potential value for large scale management programmes of forest pathogens such as Phytophthora spp. In what is possibly a world first, Paddy the Labrador is being trained to detect kauri dieback disease (Phytophthora agathidicida). This talk will outline the process of Paddy’s training to date, including results from handler-blinded specificity and sensitivity testing from stage one of his training. This includes testing his ability to distinguish P. agathidicida from the con-generic and widely occurring P. cinnamomi and P. multivora. Next steps in the training process will be described, scaling up to more ecologically complex scenarios. Potential advantages and constraints of forest pathogen detector dogs will be discussed within the context of the kauri dieback management programme case study.

Identifying vectors of soil-borne forest pathogens is crucial in limiting disease spread. Phytophthora agathidicida causes kauri dieback disease, killing kauri (Agathis australis (D. Don) Lindl.), Aotearoa-New Zealand's largest endemic tree. Currently incurable, management focuses on spread prevention. Feral pigs (Sus scrofa) are implicated in spread, through ingestion of infected material; congeneric Phytophthora cinnamomi is known to survive pig gut passage. We investigated P. agathidicida survival of pig gut passage in a captive feeding experiment, and assessed P. agathidicida incidence in feral pig stomachs from DNA. We detected viable P. agathidicida from a kauri root retrieved from captive-fed pig faeces, providing proof of concept that pigs can internally vector P. agathidicida. However, we detected only one positive, despite processing a total of 11.2m of passaged roots and 800 millet (Pennisetum glaucum (L.) R. Br.) seeds, from 12 pigs. We did not detect P. agathidicida in any of 184 wild-caught feral pig stomachs, but did detect five other Phytophthora species including P. multivora and P. cinnamomi. Ingestion of contaminated material by feral pigs is probably a minor pathway for P. agathidicida, and a higher risk pathway for P. cinnamomi. We highlight the need to test Phytophthora species individually, as pathways of spread may be considerably different between related species.

Islands offer unique opportunities and challenges in biosecurity and conservation management. We review current and past island biosecurity within Tāmaki Makaurau-Auckland’s 1.2 million ha Hauraki Gulf Marine Park (HGMP), which includes 30 island groups, many of which are inhabited. We highlight evolving challenges and changes in island biosecurity focus. Eradication of introduced mammals from islands in the HGMP has restored mammal pest-free status to around 16 islands/island groups, i.e. over half. However, eradications are only part of island biosecurity and require follow-up with on-going vector control, surveillance and incursion response. Almost 35% of the population of Aotearoa-New Zealand lives in or around the HGMP, with hundreds of thousands of visitors to the islands each year, making human-mediated propagule pressure an important consideration in island biosecurity within the Park. The Treasure Islands public awareness campaign is an example of a multi-species, multi-agency approach to managing the human dimension of invasion risk. Data on introduced mammal incursions and reinvasions on predator-free islands highlight the role of both swimming and human-transport as vectors, and large inhabited islands elsewhere in the HGMP as reinvasion sources. Since 2000, biosecurity has prevented all but one incursion leading to full reinvasion. We highlight the crucial role of robust social science in supporting successful island biosecurity programmes in populous areas, and propose the Treasure Islands campaign as a case-study for providing insights into potential improvements in future use of social science in such programmes.

As urbanization intensifies, urban ecosystems are increasingly under pressure from a range of threats. Horizon scanning has the potential to act as an early warning system, thereby initiating prompt discussion and decision making about threat mitigation. We undertook a systematic horizon scanning exercise, using a modified Delphi technique and experts from wide-ranging disciplines, to identify emerging threats in urban ecosystems. The 10 identified threats were generally associated with rapid advances in technology (eg solar panels, light-emitting diode lights, self-healing concrete) or with societal demands on urban nature (eg green prescriptions). Although many of the issues identified are also technological opportunities with recognized environmental benefits, we have highlighted emerging risks so that research and mitigation strategies can be initiated promptly. Given the accelerated rate of technological advancement and the increasing demands of urbanized populations, horizon scanning should be conducted routinely for urban ecosystems.

More than 25 000 plant species have been introduced to New Zealand, with 8.5% of those having naturalised so far, and an additional 20 species estimated to naturalise each year. Two-thirds of naturalised species were introduced as garden plants. The number of recognised environmental weeds in New Zealand has almost reached 400 species. Empirical impact data exists for less than 5% of our current environmental weeds, and these are almost all widespread or locally dominant species. The research that does exist has demonstrated a variety of negative impacts, ranging from reduced native species diversity, to altered nutrient regimes. However, management of weeds is more cost effective in the early stages of weed invasion, and there is rarely empirical impact research available at these stages of invasion. While it is not feasible to conduct empirical research on the impacts of all environmental weeds in New Zealand, the development of a comprehensive framework that evaluates known impacts would help inform timely weed management decisions.

Nesting seabirds import marine-derived nutrients into terrestrial food webs, affecting invertebrate abundance and community composition directly, through provision of decaying animal matter as a food source, and indirectly through effects on vegetation and prey abundance. Invertebrates have shown strong responses to seabird presence in some, but not all, ecosystems previously studied. In contrast to mainland range contractions, New Zealand's subantarctic islands retain abundant seabird populations. We sampled ground invertebrates on mammal-free Adams Island, using pitfall traps. We surveyed sites in two vegetation types (tussock and forest) with either no nesting seabirds or nesting colonies of Gibson's wandering albatross, sooty shearwaters or white-headed petrels. We collected 11 invertebrate orders and identified 20 Coleoptera species or higher taxa. The carrion beetle, Paracatops antipoda comprised over 50 % of Coleoptera individuals collected. P. antipoda was more abundant in forest than tussock and was positively associated with sooty shearwaters and negatively associated with white-headed petrels when compared with bird-free sites using a Poisson generalized linear model. Sooty shearwaters were also associated with elevated abundance of several herbivorous and invertebrate decomposer taxa. Nesting seabirds do appear to influence invertebrate community composition on Adams Island, but the direction of this effect appears to be taxa-specific. Further sampling with spatial replication of colonies is required to determine the extent to which these apparent taxa-specific responses are consistent across colonies and habitats.

The causal agent of kauri dieback Phytophthora taxon Agathis (PTA) poses a significant threat to kauri (Agathis australis) in northern New Zealand Groundbased field surveys have previously confirmed PTA presence at several locations across Auckland and Northland However ground surveys are limited to areas adjacent to tracks because of difficulty and cost associated with offtrack access in steep terrain along with concern about furthering spread of PTA A methodology for aerial photographic surveillance of kauri dieback was developed and implemented in Wait257;kere Ranges Hunua Ranges and adjacent forest areas Using recently developed GPS technology photographs were embedded with position data so unhealthy trees were easily located later for groundtruthing Aerial survey was found to be a time and costeffective method for surveying large inaccessible areas of forest for kauri dieback The methodology would also be applicable for detection of visible disease or damage symptoms in other canopy tree species

Empirical impact evidence exists for few of New Zealand’s environmental weeds. Financial constraints prevent managers examining all impacts of all weeds. Therefore it is useful to seek generalisable rules which allow managers to predict impacts of new invasions. Invasive weeds may indirectly affect fungivorous invertebrates through mechanisms such as altered litter-fall, decomposition rates, and microclimate, all of which may alter fungal activity. I tested the hypothesis that fungivorous invertebrates would be consistently affected by three invasive weeds, and that this effect would be more pronounced than for other invertebrate functional groups. Using pitfall traps, I compared invertebrates beneath climbing asparagus, tradescantia and ginger with invertebrates of uninvaded lowland forest. Five out of six Coleoptera taxa which differed in abundance between invaded and uninvaded sites were fungivores; the remaining taxon was a saprophage. At least two taxa of fungivorous Coleoptera responded to each of the three weed species. Acari (mainly Oribatids, some of which are fungivores), Isopoda and Amphipoda (decomposers) were the only taxa to respond to the presence of all three weed species. These results provide some support for the hypothesis that fungivores are particularly responsive to ground-cover weed invasion, but suggest this could be extended to include decomposers as well. However, the direction of effect differed among weed species. Therefore, while changes in fungivore and decomposer abundance may be predicted as one of the more likely consequences of ground-cover weed invasion in New Zealand low-land forest, site- and taxa-specific effects make it difficult to predict the direction of effect.

Chemical and/or architectural differences between native and exotic plants may influence invertebrate community composition. According to the enemy release hypothesis, invasive weeds should host fewer and less specialised invertebrates than native vegetation. Invertebrate communities were compared on invasive Alternanthera philoxeroides (alligator weed) and native sedges (Isolepis prolifer and Schoenoplectus tabernaemontani) in a New Zealand lake. A. philoxeroides is more architecturally and chemically similar to I. prolifer than to S. tabernaemontani. Lower invertebrate abundance, richness and proportionally fewer specialists were predicted on A. philoxeroides compared to native sedges, but with greatest differences between A. philoxeroides and S. tabernaemontani. A. philoxeroides is more architecturally and chemically similar to I. prolifer than to S. tabernaemontani. Invertebrate abundance showed taxa-specific responses, rather than consistently lower abundance on A. philoxeroides. Nevertheless, as predicted, invertebrate fauna of A. philoxeroides was more similar to that of I. prolifer than to S. tabernaemontani. The prediction of a depauperate native fauna on A. philoxeroides received support from some but not all taxa. All vegetation types hosted generalist-dominated invertebrate communities with simple guild structures. The enemy release hypothesis thus had minimal ability to predict patterns in this system. Results suggest the extent of architectural and chemical differences between native and invasive vegetation may be useful in predicting the extent to which they will host different invertebrate communities. However, invertebrate ecology also affects whether invertebrate taxa respond positively or negatively to weed invasion. Thus, exotic vegetation may support distinct invertebrate communities despite similar overall invertebrate abundance to native vegetation. (C) 2012 Published by Elsevier Masson SAS.

Exotic plant invasions are a key threat to New Zealand biodiversity. Alligator weed (Alternanthera philoxeroides; Amaranthaceae) is an invasive, herbaceous weed native to South America. Little is known about its dynamics in natural ecosystems in its introduced range, despite known agricultural impacts. We quantified alligator weed infestation at Lake Rotokawau, Northland, and investigated alligator weed's relationship with other vegetation, both native and exotic, over a year (Nov. 2005 to Sep. 2006). We also examined the relationship between native vegetation and 'other' exotic vegetation at the site. Alligator weed, at its peak in spring, covered over 20% of the surveyed lake margin. Plant community composition of plots without alligator weed differed significantly from invaded plots even when alligator weed itself was removed from the analysis. Uninvaded plots were characterised by low beta-diversity and predominantly terrestrial plant species, with Phormium tenax contributing 41% of within-group similarity. In contrast, invaded plots had higher beta-diversity and were characterised by a variety of emergent sedges and herbs. Alligator weed cover was negatively related to cover of natives but not cover of 'other' exotics. Alligator weed cover was not related to species richness of natives or 'other' exotics. 'Other' exotic species were positively related to native cover and richness, likely due to shared responses to favourable environmental conditions.

Invasive Alternanthera philoxeroides (alligator weed), when controlled by biocontrol agent Agasicles hygrophila, is known to differ from native vegetation in its decomposition dynamics. This study investigated whether this difference would have indirect effects for fungal-feeding Coleoptera. The study tested the hypothesis that fungivores would be more abundant and species rich on A. philoxeroides than on native vegetation. The study also tested the hypothesis that fungivores would be more affected than other functional groups. The study was conducted in a northern New Zealand lake. Litterbags were placed beneath A. philoxeroides and two native sedge species (Schoenoplectus tabernaemontani and Isolepis prolifer). Coleoptera communities were examined from the litterbags. Fungivorous Coleoptera were more abundant and species rich beneath A. philoxeroides than beneath either sedge species. No other functional groups differed between cover types. Fungivorous Coleoptera also comprised a greater proportion of total Coleoptera catch from litterbags beneath A. philoxeroides cover than from beneath native sedge cover. Four of the six fungivorous Coleoptera species collected in the study were present beneath A. philoxeroides cover. Of these, the two most abundant species (on native, one exotic) were both from the family Corylophidae. Alternanthera philoxeroides invasion is thus associated with altered Coleoptera communities in this ecosystem.

Terrestrial Alternanthera philoxeroides is difficult to control with current tools. Shading as a control tool depends on the relative shade tolerances of the target weed and co-occurring species. This study examined A. philoxeroides' shade tolerance with inter-specific competition from pasture species. In glasshouse conditions, shade and competition reduced A. philoxeroides growth but did not cause senescence. Grasses senesced in response to shade. In the field, competing species' biomass reduced by over 90% in shade. A. philoxeroides biomass was unaffected by shade, contrasting with glasshouse results and resulting in increased dominance in shade. Connection to unshaded ramets in the glasshouse reduced some, but not all, of the differences between shaded and unshaded plants. Thus, resource sharing likely facilitated A. philoxeroides growth in the field, but may have been less influential than release from interspecific competition. This research suggests shading may have limited use for controlling A. philoxeroides unless shade-tolerant inter-specific competition is provided.

Invasive weeds have been shown to alter ecosystem processes such as decomposition and nutrient cycling. However, little is known about the effects of introduced biocontrol agents on these processes. This study examined the effects of alligator weed (Alternanthera philoxeroides) and its biocontrol agent, the alligator weed flea beetle (Agasicles hygrophila), on nutrient cycling in a northern New Zealand lake. Alligator weed litter decomposed significantly faster than either of two native sedge species (Schoenoplectus tabernaemontani, Isolepis prolifer) in a litterbag experiment. In addition, the presence of the alligator weed flea beetle resulted in large amounts of decaying alligator weed litter entering the lake in early summer. Both the timing and magnitude of this litter input were uncharacteristic of seasonal biomass dynamics of the native sedges. Combined with alligator weed's rapid decomposition, this indicates altered patterns of nutrient cycling at the lake, with potential flow-on effects including facilitation of further weed invasion.

Weed invasion can lead to changes in leaf litter decomposition rates, thereby altering nutrient cycling at invaded sites. Decomposition of alligator weed ( Alternanthera philoxeroides (Mart.) Griseb.) litter was compared to decomposition of litter from two native sedge species (Schoenoplectus tabernaemontani (Gmel.) Palla and Isolepis prolifer (Rottb.) R.Br.) in a northern New Zealand lake. Alligator weed biomass was also measured monthly to quantify litter inputs into the lake. Alligator weed litter decomposed faster than both of the sedge species, with over 60% of alligator weed litter being lost from litter bags within the first three weeks of the study. In comparison, slightly less than 60% of litter from each sedge species was lost over the entire 10 week period of the experiment. In addition, alligator weed above-ground biomass dropped by 75% over the summer period following herbivory by an introduced biological control agent (Agasicles hygrophila Selman & Vogt). Large, rapid inputs of litter, uncharacteristic of those exhibited by native vegetation, along with rapid decomposition rates, may have the potential to alter nutrient cycling regimes at sites invaded by alligator weed. This could have flow-on effects, including facilitation of further weed invasion by altering temporal availability of nutrients.

Soil compaction can affect seedling root development by decreasing oxygen availability and increasing soil strength. However, little quantitative information is available on the compaction tolerances of non-crop native species. We investigated the effects of soil compaction on establishment and development of two New Zealand native species commonly used in restoration programmes; Cordyline australis (Agavaceae) (cabbage tree) a fleshy rooted species, and Leptospermum scoparium (Myrtaceae) (manuka) a very finely rooted species. Seedlings were grown in a range of soil compaction levels in growth cabinet experiments. Low levels of soil compaction (0.6 MPa) reduced both the number and speed of C. australis seedlings penetrating the soil surface. In contrast, L. scoparium seedlings showed improved establishment at an intermediate compaction level. Root and shoot growth of both species decreased with increasing soil strength, with L. scoparium seedlings tolerating higher soil strengths than did C. australis. Despite these results, soil strength accounted for only a small amount of variation in root length (R-2 < 0.25), due to greater variability in growth at low soil strengths. Soil strengths of 0.6 MPa are likely to pose a barrier to C. australis regeneration. This is consistent with adaptation to organic and/or soft, waterlogged soils. Active intervention may be necessary to establish C. australis from seed on many sites previously in farmland.