ORCID Profile
0000-0003-0701-8935
Current Organisation
The University of Auckland
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Publisher: CSIRO Publishing
Date: 2002
DOI: 10.1071/ZO01035
Abstract: Birds are important consumers and dispersers of the seeds of fleshy fruit and some have been shown to be selective in their choice of fruit. However, our knowledge of how birds respond to a variety of fruit characteristics is poor. Some birds are known to avoid green fruit or consume them less than fruit of other colours. The fruit of many plant species are green when they are unripe and contain low concentrations of sugars and high concentrations of secondary compounds. In this study, captive silvereyes (Zosterops lateralis) were presented with a choice of red, white and green artificial fruit. Half of them were given these fruit with equal sugar concentrations (15%) and the other half were given the choice but with the green fruit having a sugar concentration twice that of the other two colours (30%). Green fruit were not strongly avoided by silvereyes and were actually preferred when they had a higher sugar concentration than the other two fruit types (red and white). Sugar concentration was therefore a more important determinant of fruit choice than colour. Fruit size is also known to affect fruit choice in some bird species. Small fruit are easier to consume than larger fruit, but contain less pulp. To maximise energy gain, birds should consume fruit that are large, but not large enough to incur high handling costs. Silvereyes in this study were presented with a choice between 20 artificial fruit 4 mm in diameter (large fruit) and 20 artificial fruit 2 mm in diameter (small fruit), both of which they are able to consume. In this experiment, silvereyes exhibited a strong preference for large fruit over small fruit. In general, larger fruit contain more pulp and therefore more energy than smaller fruit. However, other fruit traits, such as seed load, are likely to influence fruit choice by silvereyes in the wild and result in a trait hierarchy.
Publisher: New Zealand Ecological Society
Date: 2016
Publisher: Cambridge University Press (CUP)
Date: 06-2014
DOI: 10.1614/IPSM-D-13-00038.1
Abstract: Climate change, comprising an increase in carbon dioxide levels coupled with elevated temperature, may favor invasive plants, as they possess traits that will facilitate adaptation to a new climate. In particular, alien plants of subtropical origin introduced to a colder region are expected to increase the number and size of their populations and spread farther with climate change. Seedlings of three such woody alien species in New Zealand ( Archontophoenix cunninghamiana, Psidium guajava , and Schefflera actinophylla ) were grown in environmental chambers under the combination of two temperature (23.7 and 26 C [74.7 and 78.8 F]) and two CO 2 (450 and 900 ppmv) regimes, simulating current conditions and conditions projected for the end of the century. Total biomass of S. actinophylla was 45% higher and total leaf area 35% larger under doubled CO 2 compared to current CO 2 . Root : shoot ratio was higher under doubled CO 2 across all species, and the number of branches was increased for P. guajava . The only significant interactive effect of elevated temperature and doubled CO 2 was for relative growth rate of the height of S. actinophylla seedlings. This study provides strong evidence of more vigorous growth of S. actinophylla under future conditions, particularly increased CO 2 , whereas the other two species appear likely to maintain current growth rates. Better knowledge of the types of future conditions that may benefit such species, together with results of species distribution models and competition and eco-physiology studies will ensure robust weed risk assessments.
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/ZO00085
Abstract: The influence of accessibility on the fruit preferences of frugivorous silvereyes (Zosterops lateralis) was examined in three different contexts: for captive in iduals, in a captive group and in a field situation. In idual silvereyes in small cages were presented with identical artificial fruit that differed only in their accessibility from a perch. The birds removed fruit that could be obtained by ‘picking’ rather than by ‘reaching up’ and avoided ‘hanging’ to remove fruit. A second experiment tested the response of silvereyes to fruit accessibility in a large aviary where birds fed in a group. The artificial fruit were presented at a larger and more natural scale on artificial trees. In this experiment, silvereyes again avoided ‘hanging’ to obtain fruit however, these birds showed no preference for ‘picking’ over ‘reaching up’. Foraging observations of silvereyes were recorded for three different plant species in the field. Silvereyes generally avoided ‘hanging’ to remove fruit, although the foraging method used varied with the species of plant on which the bird was foraging. The foraging method used by avian frugivores to remove fruit is likely to be influenced by plant morphology, as well as the morphology of the bird. The strong preference shown by silvereyes for fruit that are more accessible suggests that when other fruit characteristics are equal, accessibility is important in influencing fruit-removal patterns. However, this may be affected by the context in which the fruit is presented. Properties of the fruiting plant, such as the branching pattern, perch stability and position of the fruit display, are likely to influence fruit preference. These aspects of plant structure should be considered when assessing foraging behaviour and resource use by frugivorous birds.
Publisher: Elsevier BV
Date: 2019
Publisher: Oxford University Press (OUP)
Date: 04-2007
DOI: 10.1603/0022-0493(2007)100[509:RAOBTP]2.0.CO;2
Abstract: Exotic ant incursions are becoming more frequent around the globe, and management with toxic baits is a suitable strategy for most species. Crazy ants, (Latreille) (Hymenoptera: Formicidae), however, are notoriously difficult to attract to commercial baits, which are generally tailored to the preferences of fire ants. We tested P. longicornis preferences for various food types and commercial ant baits. Baits trialed were commercially available products Amdro, Maxforce, Xstinguish (nontoxic monitoring version), Presto, and tuna (in spring water), sugar water (25%), boric acid (1% in 25% sugar water), and deionized water. Tuna and Xstinguish, along with sugar water and sugar water + boric acid, were the most attractive baits to P. longicornis foragers. The granular baits (Maxforce, Amdro, and Presto) were not as attractive to P. longicornis foragers. A decrease in temperature from summer (30 degrees C) to autumn (23 degrees C) trials did not seem to affect the food preferences of P. longicornis. Although P. longicornis recruitment was substantially lower during trials where there was concurrent high native ant abundance and ersity, P. longicornis still recruited to preferred baits in numbers higher than any other species. Given that tuna is impractical for management programs, the effectiveness of boric acid, sweet liquid baits in eliminating P. longicornis colonies should be compared with that of the toxic version of Xstinguish. If both are effective at eliminating colonies, we recommend sweet liquid baits containing boric acid be used for small-scale incursions (one or two nests), but a more practicable solid bait, such as Xstinguish, be used for larger scale incursions (numerous nests).
Publisher: Wiley
Date: 26-04-2014
DOI: 10.1111/GCB.12531
Abstract: Climate change may facilitate alien species invasion into new areas, particularly for species from warm native ranges introduced into areas currently marginal for temperature. Although conclusions from modelling approaches and experimental studies are generally similar, combining the two approaches has rarely occurred. The aim of this study was to validate species distribution models by conducting field trials in sites of differing suitability as predicted by the models, thus increasing confidence in their ability to assess invasion risk. Three recently naturalized alien plants in New Zealand were used as study species (Archontophoenix cunninghamiana, Psidium guajava and Schefflera actinophylla): they originate from warm native ranges, are woody bird-dispersed species and of concern as potential weeds. Seedlings were grown in six sites across the country, differing both in climate and suitability (as predicted by the species distribution models). Seedling growth and survival were recorded over two summers and one or two winter seasons, and temperature and precipitation were monitored hourly at each site. Additionally, alien seedling performances were compared to those of closely related native species (Rhopalostylis sapida, Lophomyrtus bullata and Schefflera digitata). Furthermore, half of the seedlings were sprayed with pesticide, to investigate whether enemy release may influence performance. The results showed large differences in growth and survival of the alien species among the six sites. In the more suitable sites, performance was frequently higher compared to the native species. Leaf damage from invertebrate herbivory was low for both alien and native seedlings, with little evidence that the alien species should have an advantage over the native species because of enemy release. Correlations between performance in the field and predicted suitability of species distribution models were generally high. The projected increase in minimum temperature and reduced frosts with climate change may provide more suitable habitats and enable the spread of these species.
Publisher: The Royal Society
Date: 08-2022
Abstract: Sleep is one of the few truly ubiquitous animal behaviours, and though many animals spend enormous periods of time asleep, we have only begun to understand the consequences of sleep disturbances. In humans, sleep is crucial for effective communication. Birds are classic models for understanding the evolution and mechanisms of human language and speech. Bird vocalizations are remarkably erse, critical, fitness-related behaviours, and the way sleep affects vocalizations is likely similarly varied. However, research on the effects of sleep disturbances on avian vocalizations is shockingly scarce. Consequently, there is a critical gap in our understanding of the extent to which sleep disturbances disrupt communication. Here, we argue that sleep disturbances are likely to affect all birds' vocal performance by interfering with motivation, memory consolidation and vocal maintenance. Further, we suggest that quality sleep is likely essential when learning new vocalizations and that sleep disturbances will have especially strong effects on learned vocalizations. Finally, we advocate for future research to address gaps in our understanding of how sleep influences vocal learning and performance in birds.
Publisher: Proceedings of the National Academy of Sciences
Date: 25-03-2008
Abstract: The interaction between Depressaria pastinacella (parsnip webworm) and wild parsnip ( Pastinaca sativa ), in its native Europe and in its longstanding nonindigenous range in the midwestern United States, is characterized by chemical phenotype matching, ostensibly mediated by reciprocal selective responses. The first appearance of D. pastinacella on P. sativa in New Zealand in 2004 provided an opportunity to quantify selective impacts of a coevolved herbivore and calibrate rates of phytochemical response in its host plant. Webworms in 2006 reduced seed production up to 75% in New Zealand populations, and in 2007 infestations increased in severity in all populations except one. Most New Zealand populations fall into a furanocoumarin phenotype cluster distinct from European and U.S. phenotypes, although one heavily attacked population clusters with two U.S. populations and one European population long associated with webworms. Multivariate selection analysis substituting realized fitness (with webworms present) for potential fitness (absent webworms) as the dependent variable revealed that reassociation with a coevolved specialist in a nonindigenous area profoundly altered the selection regime, favoring trait remixing and rapid chemical changes in parsnip populations, as predicted by the geographic mosaic theory. That uninfested populations of New Zealand parsnips contain higher amounts of octyl acetate, a floral volatile used by webworms for orientation, suggests that plants that escape from specialized enemies may also experience selection to increase kairomones, as well as to reduce allomones.
Publisher: Elsevier BV
Date: 02-2019
DOI: 10.1016/J.YGCEN.2018.11.004
Abstract: Handling of avian study species is common in ecological research, yet few studies account for the impact of handling in nestlings where exposure to stress may result in negative lifetime fitness consequences. As a result, our understanding of stress reactivity in free-living avian young is limited. In this study we examined the cumulative impact of three levels of research-relevant handling (control, daily and every three days) on the development of the stress response, growth and condition of semi-precocial seabird chicks from near-hatching to near-fledging. By measuring corticosterone concentrations in plasma, we found that mottled petrel (Pterodroma inexpectata) chicks were capable of mounting a stress response comparable to adults from near-hatching. There were no differences in plasma corticosterone concentrations in initial s les (<4 min) between groups at six weeks of age, though by 12 weeks of age plasma corticosterone concentrations in initial s les collected from chicks handled daily were lower than chicks that were handled once every three days, and from control chicks. Corticosterone responses to handling were lower in chicks handled daily at six and 12 weeks of age when compared to other handling groups. Handling chicks daily or every three days had no negative effect on the growth or condition of chicks when compared to control chicks. These findings indicate that daily handling results in chicks became accustomed to handling, with no evidence that regular handling was detrimental to mottled petrel chicks. However, given the unique life-history characteristics of mottled petrels relative to closely related species, we caution that this finding may be species-specific, and wider testing is recommended.
Publisher: Wiley
Date: 04-2002
Publisher: Springer Science and Business Media LLC
Date: 27-06-2008
Publisher: Elsevier BV
Date: 05-2022
Publisher: Wiley
Date: 03-09-2013
Publisher: Springer Science and Business Media LLC
Date: 25-07-2012
Publisher: The Royal Society
Date: 23-12-2013
Abstract: Overlap in the form of sexual signals such as pheromones raises the possibility of reproductive interference by invasive species on similar, yet naive native species. Here, we test the potential for reproductive interference through heterospecific mate attraction and subsequent predation of males by females of a sexually cannibalistic invasive praying mantis. Miomantis caffra is invasive in New Zealand, where it is widely considered to be displacing the only native mantis species, Orthodera novaezealandiae , and yet mechanisms behind this displacement are unknown. We demonstrate that native males are more attracted to the chemical cues of introduced females than those of conspecific females. Heterospecific pairings also resulted in a high degree of mortality for native males. This provides evidence for a mechanism behind displacement that has until now been undetected and highlights the potential for reproductive interference to greatly influence the impact of an invasive species.
Publisher: Elsevier BV
Date: 2019
Publisher: Informa UK Limited
Date: 02-11-2022
Publisher: Wiley
Date: 24-07-2023
DOI: 10.1111/CSP2.12997
Abstract: The fungal genus Phytophthora includes an array of destructive plant pathogens that have had severe impacts on native, agricultural, and horticultural systems worldwide. Preventing the spread of Phytophthora species is critical for protecting vulnerable plants and ecosystems yet detection remains a challenge due to their microscopic size, broad host range, and latent and cryptic expression in host plants. We tested the effectiveness of trained detection dogs to discriminate the odor of a target Phytophthora species, from among other non‐target odors, by conducting a multi‐choice experiment. We tasked two dogs with discriminating the scent of P. agathidicida —the causal agent of the lethal root rot disease “kauri dieback”—from two non‐target Phytophthora scents ( P. cinnamomi and P. multivora ), and four non‐target control treatments. We assessed the dogs' scent detection abilities by measuring the sensitivity and precision of their indications toward the target scent over 120 randomized trials. The dogs had a combined sensitivity of 68.6% (CI: 64.1–72.9) and precision of 52.2% (CI: 48.1–56.4), meaning they often identified P. agathidicida when it was present but also signaled on the other non‐target Phytophthora species. Moreover, we characterized the nature of false positive indications made for non‐target scents, which has important implications for how future multi‐choice experiments should be conducted. Our study shows that detection dogs are likely to be an adequate first‐pass detection tool for Phytophthora within a wider biosecurity framework. However, further research is warranted before dogs can be deployed for this purpose in the field.
Publisher: JSTOR
Date: 09-1998
DOI: 10.2307/1565468
Publisher: Springer Science and Business Media LLC
Date: 03-07-2014
DOI: 10.1007/S00442-014-2999-2
Abstract: Although selection by herbivores for increased feeding deterrence in hostplants is well documented, selection for increased oviposition deterrence is rarely examined. We investigated chemical mediation of oviposition by the parsnip webworm (Depressaria pastinacella) on its principal hostplant Pastinaca sativa to determine whether ovipositing adults choose hostplants based on larval suitability and whether hostplants experience selection for increased oviposition deterrence. Webworms consume floral tissues and florivory selects for increased feeding deterrents moths, however, oviposit on leaves of pre-bolting plants. Exclusive use of different plant parts for oviposition and larval feeding suggests oviposition should select for increased foliar deterrents. Recent webworm colonization of New Zealand (NZ) allowed us to assess phenotypic changes in foliar chemicals in response to webworm oviposition. In a common garden experiment, we compared NZ populations with and without a history of infestation from 2004 to 2006 for changes in leaf chemistry in response to oviposition. Three leaf volatiles, cis- and trans-ocimene, and β-farnesene, elicit strong responses in female moth antennae these compounds were negatively associated with oviposition and are likely oviposition deterrents. Leaf β-farnesene was positively correlated with floral furanocoumarins that deter florivory greater oviposition on plants with low floral furanocoumarins indicates that moths preferentially oviposit on parsnips most suitable for larval growth. Unlike florivory, high oviposition on leaves did not lower plant fitness, consistent with the fact that NZ parsnip foliar chemistry was unaffected by 3-6 years of webworm infestation. Thus, in this system, selection by ovipositing moths on foliar chemistry is weaker than selection by larvae on floral chemistry.
Publisher: MDPI AG
Date: 27-01-2022
DOI: 10.3390/ANI12030309
Abstract: Aotearoa–New Zealand has embarked on an ambitious goal: to completely eradicate key invasive mammals by 2050. This will require novel tools capable of eliminating pests on a large scale. In New Zealand, large-scale pest suppression is typically carried out using aerial application of the toxin sodium fluoroacetate (1080). However, as currently applied, this tool does not remove all in iduals. A novel application method, dubbed ‘1080-to-zero’, aims to change this and reduce the abundances of target pests to zero or near-zero. One such target is black rats (Rattus rattus), an invasive species challenging to control using ground-based methods. This study monitored and compared the response of black rats to a 1080-to-zero operation and a standard suppression 1080 operation. No difference in the efficacy of rat removal was found between the two treatments. The 1080-to-zero operation did not achieve its goal of rat elimination or reduction to near-zero levels, with an estimated 1540 rats surviving across the 2200 ha treatment area. However, 1080 operations can produce variable responses, and the results observed here differ from the only other reported 1080-to-zero operation. We encourage further research into this tool, including how factors such as ecosystem type, mast fruiting and operational timing influence success.
Publisher: CSIRO Publishing
Date: 2001
DOI: 10.1071/ZO01042
Abstract: There are many secondary metabolites in ripe fruit that are toxic to vertebrate consumers. The most prevalent explanation for their presence in ripe fruit is to protect the fruit against consumers that do not disperse viable seeds. It has been hypothesised that seed dispersers are not deterred by, or can tolerate, the consumption of secondary metabolites in ripe fruit. We tested whether silvereyes (Zosterops lateralis), which are known seed dispersers, were deterred by quebracho (condensed tannins) presented in two different food types. In the first experiment, silvereyes were given artificial fruit containing either 0% or 5% quebracho and their fruit consumption was measured. A second experiment recorded consumption of a cereal-based, long-term maintenance diet containing either 0% or 5% quebracho. Silvereyes did not exhibit a significant preference for artificial fruit that did not contain quebracho: 39.9% of the fruit consumed did contain quebracho. However, silvereyes strongly avoided the cereal diet containing quebracho, consuming, on average, only 0.36 g (0.06 g) of cereal per 5 h compared with 17.3 g (0.23 g) of cereal that did not contain quebracho. We suggest that because the artificial fruit were swallowed whole by silvereyes, the quebracho may not have been detected as easily in the time available as it would have been in the aqueous cereal diet. Consumption of fruit containing secondary metabolites by wild silvereyes is likely to depend on factors such as food availability, nutrient content of the fruit and the degree of diet mixing.
Publisher: Springer Science and Business Media LLC
Date: 22-11-2013
DOI: 10.1007/S10164-013-0391-Z
Abstract: Inclusive fitness theory predicts that cannibalism should be more likely to arise if close relatives can be avoided, suggesting that cannibalistic species will possess mechanisms for minimizing predation on kin. Juvenile Miomantis caffra are good candidates for the possession of such traits because (1) groups of siblings hatch together into the same locale, (2) they are aggressive hunters, and (3) they are strongly cannibalistic. In this study, the possibility of kin recognition or avoidance in M. caffra is investigated by laboratory comparison of cannibalism rates between groups of differing relatedness. In order to examine the likelihood of encounters between early instar siblings, the extent of dispersal away from the ootheca in the days following hatching is also observed. Nymphs did not rapidly disperse after hatching, so the chances of full siblings encountering one another in the wild appear to be high. Despite this, cannibalism was equally high in groups of full siblings and groups of mixed parenthood. We suggest that for M. caffra , a generalist ambush predator, the benefits of indiscriminate aggression may outweigh any inclusive fitness benefits that would be gained from kin discrimination.
Publisher: Wiley
Date: 18-04-2012
Publisher: Public Library of Science (PLoS)
Date: 2014
Publisher: Springer Science and Business Media LLC
Date: 10-07-2012
Publisher: Wiley
Date: 23-01-2023
Abstract: The global pet trade provides a pathway for introduced species to invade new environments. Most studies use trade data as an indirect proxy for propagule pressure exerted by the pet trade. Instead, we quantify the reported rate of loss of captive birds, assess factors that might influence this rate, simulate the survival and retrieval of birds and the overall cumulative propagule pressure exerted by pet birds on the environment. We used online listings of lost birds to estimate the propagule pressure that the pet trade exerts on the establishment of introduced bird species in Aotearoa–New Zealand. Listings from two popular websites were monitored daily for over 3.5 years, and information was recorded on the frequency, location, species composition and characteristics of the loss events. We investigated a range of factors that may influence the rate of loss events, such as season and human population size. We also developed a simulation approach to investigate the cumulative propagule pressure in Auckland, New Zealand's largest city. A total of 1205 birds and at least 33 species were reported lost nationwide during our monitoring period, 92% of which were parrots. We found that the reported loss rate was higher in areas of higher human population size and median income, and lower in the winter months. Simulation results predict that in any given month in Auckland there is an average of at least 491 escaped birds, including 136 potential breeding pairs, and for seven species the chance that at least one locality has a male/female pair at large exceeds 80%. Synthesis and applications . Online listings of lost pets provide an excellent source of data from which to identify species with high propagule pressure in specific localities. We identified escaped parrot species as a high‐risk invasion pathway, as they contribute to a high and consistent propagule pressure. A preventative approach, by banning the sale of these species, is the most appropriate pest management strategy for reducing the probability of establishment and potential impact.
Publisher: Springer Science and Business Media LLC
Date: 16-03-2013
Publisher: Wiley
Date: 15-05-2020
DOI: 10.1002/PAN3.10093
Publisher: New Zealand Ecological Society
Date: 07-02-2020
Publisher: New Zealand Ecological Society
Date: 09-06-2022
Publisher: Cold Spring Harbor Laboratory
Date: 26-06-2020
DOI: 10.1101/2020.06.24.170274
Abstract: Understanding how spatial heterogeneity affects movement and dispersal is critical for maintaining functional connectivity in agroecosystems. Least-cost path models are popular conservation tools to quantify the cost of a species dispersing though the landscapes. However, the variability of species in life history traits and landscape configurations can affect their space-use patterns and should be considered in agroecosystem management aiming to improve functional bio ersity. In this study, we modelled the connectivity properties of native species on a real agroecosystem landscape dominated by sheep and beef farming in north Canterbury, New Zealand, where the recovery of native bird population is desired. We chose two species to act as case studies that were contrasting in their mobility: New Zealand pigeon/kererū ( Hemiphaga novaeseelandiae highly mobile) and southern brown kiwi/tokoeka ( Apteryx australis flightless). Networks of the least-cost paths of kererū and tokoeka were constructed based on their habitat preferences and movement capacities, and we compared and contrasted the connectivity properties and network topographies of their networks. We then compared the network metrics of western side (higher density of forest) with the eastern side (dominated by grazed grassland) of the study area where the vegetation composition was vastly different for both species. The results shown three variables were the most important contributors to the structure of the dispersal networks: the nature of the matrix, spatial structure of vegetation patches, and the gap-crossing ability of the study species. Tokoeka were able to utilise smaller habitat patches as stepping-stones for dispersal, while kererū can select more preferred habitat patches due to their high movement capacity. In contrast to the eastern side, we observed the western/forested side to have more, and stronger, links among habitat patches for both species, due to the presence of several large patches of native forest. Our work suggested that one size does not fit all, rather, conservation strategies that account for species’ life histories and movement traits are required to identify and preserve a connected ecological network.
Publisher: New Zealand Ecological Society
Date: 10-2022
No related grants have been discovered for Margaret Stanley.