Margaret C. Stanley

Most weed research has focused on single species, whereas managers of conservation habitats often deal with multiple co-occurring species. Effective multi-weed management in revegetation plantings is crucial to prevent unintended responses to the removal of single species, which can change the successional trajectory of the planting project. Predicting positive and negative weed associations can help managers prioritise weed removal to prevent unintended responses from co-occurring weeds. Seedling plots were used to identify species co-occurring under each of three target woody weeds in revegetation plantings in Auckland, Aotearoa – New Zealand ( Solanum mauritianum , Paraserianthes lophantha , and Ligustrum lucidum ) and compare them with seedlings growing under native plants. Twenty-four pairs of weed species were significantly correlated with each other’s occurrence, either positively (often found together) or negatively (rarely found together). Mature, shade-tolerant L. lucidum was significantly correlated (both positively and negatively) with the most weed species ( n = 9). Nitrogen-fixing P. lophantha had one positive and one negative pairwise association with other weed species, while allelopathic S. mauritianum had two negative associations. Shared bird dispersal and shade tolerance were associated with an increased probability of co-occurrence for seedlings. While bird-dispersed seedlings arrive at the site together, their associations are subsequently shaped by interspecific interactions, such as competition and facilitation. Higher housing density, resident native species richness, and vascular vegetation cover were all associated with higher weed richness, whereas higher human population density was associated with lower weed richness. Woody weeds, particularly shade-tolerant and bird-dispersed species, should be prioritised by managers of urban revegetation projects.

Invasive ants can cause enormous damage across multiple sectors and are targeted by eradication programmes where infestations are relatively small, to prevent spread and impact. However, ant eradication programmes can fail if detection and control techniques do not target species‐specific behaviours. Existing techniques for detecting invasive ants at low density (new incursions or the ‘mop‐up’ final phase of eradication) assume ants are foraging above‐ground. While tools and devices deployed above‐ground are effective for many species, some ant species forage below‐ground and can be difficult to detect above‐ground at low density using these methods. Darwin's ant ( Doleromyrma darwiniana ), a pest ant species in New Zealand, offers a unique opportunity to investigate the deployment of below‐ground lures for improved species‐specific management. This species appears to forage below‐ground more than other pest ant species currently managed in New Zealand, making eradication difficult. Here, we tested whether below‐ground lures are more effective at detecting Darwin's ant than lures deployed above‐ground. First, we used several lure types that are commonly used as ant attractants (carbohydrate, lipid, protein, combination) and presented these above‐ and below‐ground to compare relative effectiveness in attracting Darwin's ants. Second, we took the most attractive treatment (comprising lure type and presentation method) and tested this against the current best industry practice for monitoring (a commercial non‐toxic protein lure presented above‐ground) in low‐density detection trials. We found the odds of detection with our newly tested treatment (carbohydrate, below‐ground) were 2.5 times better than the above‐ground current best industry practice. Practical implication . We demonstrate that by taking foraging behaviour into account, detection at low density can be improved, thereby enhancing the probability of ant eradication. The new below‐ground deployment lure we have developed for pest ant management could be applied globally to pest ant management programmes, particularly where poor detection at low density is hindering eradication.

Landscape structure can affect movement, which is influenced by foraging, thermoregulation, and predation risk. We evaluated search paths relative to landscape cover for a unisexual lizard (Aspidoscelis uniparens) whose movement is primarily motivated by foraging. In outdoor enclosures, we arranged artificial plants in three distributions (uniform, mildly clumped, heavily clumped cover), testing the hypotheses that search effort and efficiency will vary with landscape configuration, and that movement patterns will reflect changes in foraging to accommodate thermoregulation and predation avoidance. We recorded movement parameters, assessing search paths relative to effort, efficiency, and space use. Effort did not vary with landscape configuration, but efficiency, movement patterns, and space use varied with plant distribution. With mildly clumped cover, lizards entered plants more frequently than in other cover configurations. Lizards in both clumped configurations preferentially used areas with more plants. Plant residence times also varied—short-duration visits occurred most often with mildly clumped cover, but with heavily clumped cover, long-duration visits were most common and median residence times were longest. The likelihood of moving to the nearest plant was highest with uniform cover, and that of revisiting plants was lowest with heavily clumped cover. The distribution of cover influenced movement patterns, space use, and search efficiency, likely arising from variation in predation risk.

The optimal search strategy for foraging animals can vary based on environmental parameters, which can include information about the spatial distribution of prey. We tested the hypothesis that natural populations of foraging desert grassland whiptails (Aspidoscelis uniparens) structure their search strategies according to resource distribution. We experimentally provisioned prey in uniform, aggregated, and random distributions to characterize search effort (moves per minute and percent time moving) and search path (turn angles, movement duration, path straightness, step length, and two-step sequences). The search effort did not vary with treatment but animals adjusted their search path based on the presence and distribution of supplemental prey. With uniformly distributed prey, foragers took longer step lengths and more frequently engaged in two-step sequences that included long step lengths. When prey were randomly distributed, foragers made more moves of long duration and fewer straight moves, often pairing short step lengths with large turns. With an aggregated prey distribution, foragers had more moves of very short duration. Examining detailed search path characteristics can identify responses to environmental changes. Under experimental conditions, the search strategies of A. uniparens indicated behavioral responses to food distribution that could improve search efficiency.

Vocal communication serves several critical functions, such as species recognition, mate attraction and resource defence. However, environmental and physiological factors like urbanization, noise pollution and stress can negatively affect vocal performance, especially in birds. While several studies have demonstrated the effects of various disturbances on bird vocalizations, very few have tested how lack of sleep affects birdsong. To investigate the importance of sleep for adult birds’ vocalizations, we analysed the vocal performance of captive common mynahs ( Acridotheres tristis ) after three sleep disturbance experiments: the entire night, first 6 h of the night or last 6 h of the night of sleep disturbance. Sleep disturbances altered song performance, specifically by reducing song output and complexity, but did not affect call output. Sleep disturbances also affected call spectral parameters. These effects varied according to the degree of disturbance, strongest in a full night of sleep disturbance, followed by the first 6 h of the night and last 6 h of the night, respectively. These results indicate that even short-term sleep disturbance can affect adult birds’ vocalizations’ frequency and structure. These changes could alter birds’ communication, negatively impacting social interactions and the acquisition of resources and mates, potentially affecting fitness.

Cities are increasingly recognised as important sites for biodiversity and essential for improving human-nature connections. However, urban areas are also hotspots for rats, which negatively impact biodiversity due to competition and depredation. Urban residents may undertake rat control on their properties, but the effectiveness of such volunteer initiatives for broader biodiversity outcomes has not been tested in urban environments. We conducted a comprehensive study inclusive of rat abundance, adult bird diversity, and bird breeding success. We monitored rat (Norway rat Rattus norvegicus; ship rat Rattus rattus) presence and modelled detection probabilities and occupancy in suburban residential backyards in Auckland, New Zealand. We also compared bird abundance and richness among backyards and recorded 140 nesting attempts from 15 bird species between September 2021 and February 2022. Despite rat control, rats were detected at some point in all backyards, though relative abundance was low, and fewer rats were detected in backyards with more frequent rat control. Higher bird abundance, and to a lesser extent richness, were associated with proximity to native vegetation patches and more frequent rat control. Overall fledging success was relatively high and predation by rats was relatively low compared to previous research. Nest survival was slightly higher for introduced bird species. Daily nest survival rate increased with nest height, proximity to native vegetation patches, and when rat detection rates decreased. Although the effect was small, frequent rat control within a backyard was associated with increased fledging success and increased bird species richness and abundance. Further research is required to explore the factors that interact with backyard rat control to improve local outcomes for birds. High levels of community participation in backyard rat control are required to improve neighbourhood-wide outcomes for birds.

There is an increasing disconnect between people and nature as we become more urbanised. Intensification in cities often results in a reduction of natural areas, more homogenised and manicured green spaces, and loss of biota. Compared to people in rural areas, urban dwellers are less likely visit natural areas and recognise and value biota. Reconnecting people with nature in the city not only benefits human mental and physical wellbeing but can also have positive effects on how people value biodiversity and act on conservation issues. However, in some contexts, the push to reconnect people with nature may have unintended negative outcomes on biodiversity, particularly if place-specific nature is not used in urban greening. In the current biodiversity crisis, using vegetation and green space design that is not reflective of the environmental context of a city can further disconnect residents, particularly Indigenous people, from their local environment and species, and further entrench extinction of experience and loss of environmental values. This disconnect can result in residents applying wildlife gardening practices, such as bird feeding, that are not specific to place, and benefit introduced species over indigenous species. Furthermore, cities are gateways for invasive species, and using species in greening projects that are not locally sourced has already left cities and their surrounding regions with a large weed legacy. Using place-specific nature and green space in cities can be less resource intensive, highly beneficial for biodiversity and give residents a unique sense of place. Rather than simply adding ‘more nature’ in cities, the messaging should be more complex, emphasising the need for urban greening to be context specific to avoid negative impacts on biodiversity and ecological and cultural services.

Vocalization is an important communication tool that can reflect many aspects of an individual's internal and external condition. This is especially true for birds. Previous research has shown that bird calls and songs change in response to a variety of potential stressors, although the extent and direction of the changes depend on the nature of the stressor and the environment. Circulating glucocorticoids, such as corticosterone, often increase in response to stressors and mediate some of the observed changes via alterations of the individual's physiological state. Acute elevations of corticosterone often occur as a physiological response to short‐term stressors; however, the effects of this elevation on adult vocalizations have not been well documented. Here, we experimentally elevated corticosterone at two different levels using a noninvasive method and examined the effects on the vocal communication of male and female adult common mynas (Acridotheres tristis). Corticosterone elevation temporarily increased song output and some measures of song complexity, while call output decreased. These effects were dosage dependent (higher corticosterone levels had a stronger effect), most evident 40 min after ingestion, and some vocal changes were sex‐specific. Future studies should investigate whether the changes in vocal performance due to elevated glucocorticoids have consequences for the birds' behavior, reproductive success, and survival.

Habitat fragmentation can influence the diet of mammalian predators, potentially increasing their impact on prey species. Agroecosystems are fragmented landscapes that often have high densities of invasive mammalian predators. Feral cats are generalist predators that have successfully adapted to living in agricultural landscapes. Feral cats are known to eat rabbits, rodents, and birds, but it is unclear how landscape characteristics affect prey consumption. Here, we tested whether feral cat diet in New Zealand agroecosystems was affected by landscape composition and spatial configuration. We examined the contents of 112 feral cat gastrointestinal tracts collected from agroecosystems in different New Zealand regions over a 3-year period. We related prey richness and composition to the landscape composition and spatial configuration in a 500-ha area within which each cat was caught. Dietary analysis showed that feral cats were consuming invertebrates, birds, rodents, and rabbits, and that there were some regional and seasonal effects. No significant differences in prey richness or composition of the diet were associated with variation in landscape composition or spatial configuration. This study confirms feral cats as generalist predators that feed on a wide range of prey types in New Zealand agroecosystems, including some native species. Our study highlights the importance of further research for understanding how current conservation interventions in New Zealand, which include revegetation and rodent control, interact with feral cat populations and behaviours to impact on future biodiversity outcomes.