Margaret Stanley | The University of Auckland (original) (raw)

Papers by Margaret Stanley

Frontiers in Forests and Global Change

Tree planting has long played a major role in the New Zealand Government’s approach to climate mi... more Tree planting has long played a major role in the New Zealand Government’s approach to climate mitigation and is increasingly understood as important for climate adaptation. However, large-scale tree planting in Aotearoa New Zealand has been dominated by exotic species. Although there is growing public and expert support for using native species for forest revegetation in farm landscapes, there are two key barriers. First, the lack of ecological and economic data on native species performance in different environmental conditions. Second, policy and market-related mechanisms associated with carbon sequestration, such as the New Zealand Emissions Trading Scheme, favor the continuing use of exotic tree species, especially Pinus radiata, over native species. Consequently, there are strong incentives for exotic forests and insufficient financial support for natives, even when native forest re-establishment is often the preference of landowners, Indigenous peoples, and local communities....

Journal of Ethology, Nov 22, 2013

Frontiers in Ecology and Evolution, Aug 2, 2017

Environmental Entomology, Dec 3, 2020

Ants represent a highly diverse and ecologically important group of insects found in almost all t... more Ants represent a highly diverse and ecologically important group of insects found in almost all terrestrial ecosystems. A subset of ant species have been widely transported around the globe and invade many natural ecosystems, often out-competing native counterparts and causing varying impacts on recipient ecosystems. Decisions to control non-native ant populations require an understanding of their interactions and related impacts on native communities. We employed stable isotope analysis and metabarcoding techniques to identify potential dietary niche overlap and identify gut contents of 10 ant species found in natural ecosystems in Aotearoa New Zealand. Additionally, we looked at co-occurrence to identify potential competitive interactions among native and non-native ant species. Ants fed mainly across two trophic levels, with high dietary overlap. Relative to other ant species sampled, two non-native ant species, Linepithema humile and Technomyrmex jocosus, were found to feed at the lowest trophic level. The largest isotopic niche overlap was observed between the native Monomorium antarcticum and the invasive Ochetellus glaber, with analyses revealing a negative co-occurrence pattern. Sequence data of ant gut content identified 51 molecular operational taxonomic units, representing 22 orders and 34 families, and primarily consisting of arthropod DNA. Although we generally found high dietary overlap among species, negative occurrence between a dominant, non-native species and a ubiquitous native species indicates that species-specific interactions could be negatively impacting native ecosystems. Our research progresses and informs the currently limited knowledge around establishing protocols for metabarcoding to investigate ant diet and interactions between native and non-native ant species.

Arthropod-plant Interactions, Jul 25, 2012

ABSTRACT The direct and indirect interactions of invasive ants with plants, insect herbivores, an... more ABSTRACT The direct and indirect interactions of invasive ants with plants, insect herbivores, and Hemiptera are complex. While ant and Hemiptera interactions with native plants have been well studied, the effects of invasive ant–scale insect mutualisms on the reproductive output of invasive weeds have not. The study system consisted of Argentine ants (Linepithema humile), boneseed (Chrysanthemoides monilifera monilifera), and sap-sucking scale insects (Hemiptera: Saissetia oleae and Parasaissetia nigra), all of which are invasive in New Zealand. We examined the direct and indirect effects of Argentine ants on scale insects and other invertebrates (especially herbivores) and on plant reproductive output. Argentine ants spent one-third of their time specifically associated with scale insects in tending behaviours. The invertebrate community was significantly different between uninfested and infested plants, with fewer predators and herbivores on ant-infested plants. Herbivore damage was significantly reduced on plants with Argentine ants, but sooty mould colonisation was greater where ants were present. Herbivore damage increased when ants were excluded from plants. Boneseed plants infested with Argentine ants produced significantly more fruits than plants without ants. The increase in reproductive output in the presence of ants may be due to increased pollination as the result of pollinators being forced to relocate frequently to avoid attack by ants, resulting in an increase in pollen transfer and higher fruit/seed set. The consequences of Argentine ant invasion can be varied; not only does their invasion have consequences for maintaining biodiversity, ant invasion may also affect weed and pest management strategies.

Biological Conservation, Dec 1, 2014

BioScience, Nov 13, 2019

Global changes are predicted to facilitate the introduction, establishment, and spread of species... more Global changes are predicted to facilitate the introduction, establishment, and spread of species into new environments leading to potential negative impacts on local biodiversity. Evaluating the risk associated with introduced species with a high likelihood of arrival, or species that have already been introduced, is therefore increasingly important. In the present article, we outline an operational framework to provide a basis for assessing the ecological risk of introduced species in order to facilitate justifiable management decisions. The framework integrates information based on both the species and the (potential) recipient ecosystems, using existing tools to guide pest managers through the stepwise process. This enables the prediction of high-risk species and the identification of those ecosystems most vulnerable to invasion, and facilitates understanding of the potential mechanisms and magnitude of pest impacts. The framework can be applied to different invasion scenarios to evaluate the risks and impacts of species.

Restoration Ecology, Jan 23, 2015

Native re‐forestation is a widely used restoration tool, typically undertaken with the expectatio... more Native re‐forestation is a widely used restoration tool, typically undertaken with the expectation that planting native trees will initiate succession processes (including the re‐establishment of native fauna) that will eventually return the ecosystem to a native‐dominated state. Invertebrate groups can be used to assess restoration progress, as their life history traits enable them to respond more rapidly to environmental change than many other organisms. In this study, we assessed beetle responses to re‐forestation. Using two trapping methods (flight intercept traps and pitfall traps), we compared beetle assemblages in exotic pasture (pre‐restoration state), <10‐year‐old planted native forest (restoration intervention) and approximately 40‐year‐old unmanaged regenerating native forest (reference state). Analysis of the flight intercept‐trapped beetles suggests that re‐forestation has initiated a transition from an exotic‐dominated pasture fauna toward a native‐dominated fauna: in planted forests, 75% of all flight‐intercept‐trapped beetles were native (compared with 22% in pasture and 87% in unmanaged forest). Flight intercept‐trapped beetles also had higher native diversity and abundance in both forest types than in pasture. Pitfall‐trapped beetle species were predominantly native in both forest types, but there were few statistically significant differences between the forests and pasture in the pit‐fall trap data set. Both trapping methods detected significant compositional differences between the beetle assemblages in planted forest and unmanaged forest. Replanting native forest has increased native beetle diversity, abundance, and dominance (compared with the pre‐restoration state), but convergence with the unmanaged reference forest has not yet been achieved.

Journal of Avian Biology, Feb 21, 2017

Wild bird feeding often results in high densities of birds, potentially facilitating transmission... more Wild bird feeding often results in high densities of birds, potentially facilitating transmission of disease. Wild birds are major reservoirs of many zoonotic diseases, and although a number of avian disease outbreaks have been linked to bird feeders, urban bird-feeding and its role in disease systems remains poorly studied. We examined the impacts of typical supplementary feeding practices on the health status of feeder-visiting birds at experimental feeding stations in an urban area of New Zealand. Over an 18-month period, we screened birds captured at feeding and non-feeding properties for three pathogens and four groups of parasites to determine whether feeding altered disease dynamics. We also assessed body condition. All pathogens and parasites were detected in at least one garden bird species. Feeding stations tested positive for Salmonella enterica Typhimurium on ∼7% of occasions, confirming that structures used in feeding are a potential transmission pathway. Feeding influenced some parasite infection parameters; these effects varied among host species. In silvereyes Zosterops lateralis, helminth prevalence and abundance were lower at feeding properties compared to non-feeding properties. In contrast, Eurasian blackbirds Turdus merula at feeding properties had a higher abundance of helminths. House sparrows Passer domesticus at feeding properties had a higher abundance of feather lice. Furthermore, our feeding regime significantly affected body condition in house sparrow and silvereye, though no associations between parasite parameters and body condition indices were found. Our results demonstrate that feeding practices can have varied effects on avian health, including no observable effects for some disease agents in some host species. Disease risks are present, however, thus understanding and reducing these risks should be a key goal for all stakeholders to protect birds that use feeders and other wildlife.

New Zealand Journal of Ecology, Feb 7, 2020

Biological Conservation, Feb 1, 2021

Abstract Artificial light at night (ALAN) causes a wide range of ecological impacts across divers... more Abstract Artificial light at night (ALAN) causes a wide range of ecological impacts across diverse ecosystems. Most concentrated in urban areas, ALAN poses a particular risk to associated wildlife by disrupting physiology, behaviour and ultimately survival. This risk is predicted to shift as nighttime lightscapes in many cities undergo change. Globally, streetlights are currently being retrofitted with newer technologies that differ in the spectrum and intensity of their emissions, but there is a dearth of in situ urban experiments on the ecological impacts of this change. We monitored timing of dawn and dusk bird song; frequency of owl vocalisations; avian diversity, relative abundance and community composition; small invasive mammal and ground insect activity; and invertebrate relative abundance at 26 residential properties over an 18-month period that coincided with a retrofit from high-pressure sodium (HPS) to white light-emitting diode (LED) streetlights. Initiation time of dawn song was advanced or delayed for two bird species following the retrofit and backyard avian community composition was altered. Avian species richness, relative abundances of three bird species and ground insect activity increased in the presence of LED streetlights. No other retrofit effects were found. Our study suggests that retrofitting streetlights with white LEDs may lead to both positive and negative conservation outcomes for urban wildlife, but direct impacts are relatively small and may be mitigated by changes in lighting characteristics, such as dimming. Streetlight retrofits could provide an opportunity to reduce the impacts of ALAN on urban wildlife if intentionally designed with conservation benefits in mind.

Urban Ecosystems, Aug 6, 2021

Light pollution is an issue of global significance for urban ecosystems, especially where areas o... more Light pollution is an issue of global significance for urban ecosystems, especially where areas of natural and ecological importance are located in and around cities. We investigated levels of night sky brightness around Auckland, Aotearoa-New Zealand, to determine the extent of sky glow, its potential to mask the lunar cycle, its relation to land use and the risks it poses to nearby areas of natural and ecological importance. Annual measurements of night sky brightness were carried out over 3 years at 115 randomly chosen sites within 15 km of Auckland’s city centre. In addition, continuous nightly measurements of sky brightness were taken at 6 urban residential sites for 18 months. We found that levels of sky glow in urban Auckland mask the lunar cycle to some extent and modelling suggests that nearby marine and terrestrial areas of ecological importance are at risk. In 2015 and 2016, > 95% of the total expanse of these areas was predicted to be experiencing night skies brighter than natural levels. Increased night sky brightness was associated with proximity to the city centre, commercial and industrial land use, and densities of buildings and streetlights. Reducing sky glow in and around the city should be a management priority, directed at commercial and industrial land-use zones while restricting urban sprawl near areas of natural and ecological importance.

New Zealand Journal of Ecology

Journal of Urban Ecology, 2021

Feeding backyard birds with sugar water is increasingly popular in urban areas, but it has poorly... more Feeding backyard birds with sugar water is increasingly popular in urban areas, but it has poorly understood effects on bird assemblages. In New Zealand, ca. 20% of households engaged in feeding wild birds use sugar water, often in an attempt to attract native, nectarivorous birds. Developing best practices for sugar water feeding could be a powerful tool for attracting these species in urban areas. However, it is currently unclear whether these feeders actually support native species, and, if so, which feeding practices are most effective in increasing visitation. We surveyed New Zealanders who provide sugar water to birds about their feeding practices via an online questionnaire. The aim of our research was to understand existing practices and their effect on attracting native species, as well as the motivations and social factors behind urban sugar water bird feeding. Our results show that this practice is popular throughout the country with the majority of households successful ...

Nature Ecology & Evolution, 2021

Frontiers in Ecology and the Environment, 2021

Rapid advances in eradicating invasive species from islands are improving conservation outcomes i... more Rapid advances in eradicating invasive species from islands are improving conservation outcomes in these biodiversity hotspots. However, recent conservation gains could be reversed not only by future invasions from non‐native species but also by future extinctions of native taxa, both of which may be facilitated by – or exacerbated by interactions among drivers of – global environmental change. We highlight relevant knowledge gaps that must be filled to reduce uncertainty about the ecological effects of future climate change. We use Aotearoa New Zealand as a case study of island ecosystems to demonstrate that in addition to sea‐level rise, most ecologically meaningful impacts of climate change on biodiversity responses are indirect and due to exacerbation of existing threats, including the impact of invasive species as well as the loss and fragmentation of habitat. We identify key topics where progress is needed to future‐proof conservation management for island ecosystems susceptib...

General and Comparative Endocrinology, 2018

Forestry: An International Journal of Forest Research, 2017

Proceedings of the National Academy of Sciences, 2008

The interaction between Depressaria pastinacella (parsnip webworm) and wild parsnip ( Pastinaca s... more 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 fitne...