19 results for Aguilar, Glenn

  • Screening of algorithms for ensemble modelling of marine and terrestrial invasive species to New Zealand

    Aguilar, Glenn; Gilchrist, Rowena; Blake, Jett (2013)

    Conference item
    Unitec

    Performance based screening of species distribution model (SDM) outputs to produce an ensemble of results was used to determine the suitability of New Zealand to highly threatening terrestrial and marine invasive species. Recorded occurrences of the yellow crazy ant (Anoplepis gracilepis) and Northern Pacific sea star (Asterias amurensis) in the nearest land masses were used as presence data for the models. The modeling process also employed terrestrial environmental variables from the Worldclim database and marine environmental layers from the BioOracle database. Performance evaluation metrics including the Area Under Curve (AUC), kappa and true skill statistic (TSS) were used as the basis for selecting the best performing algorithms used for creating ensembled outputs. The resulting maps show that the coastal waters of the country have generally higher suitability for the sea star while the terrestrial areas are not as suitable for the yellow crazy ant. Results provide an indication of the comparative performance of different algorithms, the limits of available environmental datasets and applicability of an ensemble approach to marine and terrestrial species distribution modeling.

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  • Ensemble species distribution modelling of Coleoptera in Viti Levu, Fiji

    Waqa-Sakiti, Hilda; Aguilar, Glenn; Winder, Linton (2013)

    Conference item
    Unitec

    Species distribution modelling (SDM) was used to characterise the distribution of nine families of the Order Coleoptera (Beetles) on the island of Viti Levu, Fiji. Occurrence data were sourced from the Global Biodiversity Information Facility and a recent survey, together with available bioclimatic layers. A set of suitability maps was produced as a result of employing various algorithms and a consensus of results of the best performing algorithms finally resulted in a single map which displays the spatial characteristics of Coleoptera distribution. The ensemble model for Coleoptera identified an altitudinal transect in southeastern Viti Levu within low to upland forested areas as most suitable for Coleoptera. As the transect extended to higher altitudes (cloud forest) the suitability was reduced to medium suitability. The results of this study correspond well with the already established PABITRA (Pacific Asia Biodiversity Transect) Gateway transect, Western Belt sites for Fiji which runs through the lowland forests of Savura to the upland forests of Waisoi and up the cloud forests of Navai and further support its selection as a representation of Fiji’s rich and unique biodiversity. An assessment of the impacts of future climate change on Coleoptera distribution along this PABITRA transect will be highlighted. Therefore, in terms of the identification of possible Protected Areas in Viti Levu, it would be wise for planners and managers to protect areas along this altitudinal transect on the southeastern site of Viti Levu.

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  • The good news and bad news about the African club moss (Selaginella kraussian)

    Blanchon, Dan; Nessia, Haley; McClymont, M.; Dale, Arnja; Perrot, J.; Aguilar, Glenn; Waipara, N. (2013)

    Conference item
    Unitec

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  • Using predicted locations and an ensemble approach to address sparse data sets for species distribution modelling : Long-horned beetles (Cerambycidae) of the Fiji islands

    Aguilar, Glenn; Waqa-Sakiti, Hilda; Winder, Linton (2016-12-09)

    Journal article
    Unitec

    Several modelling tools were utilised to develop maps predicting the suitability of the Fiji Islands for longhorned beetles (Cerambycidae) that include endemic and endangered species such as the Giant Fijian Beetle Xixuthrus heros. This was part of an effort to derive spatially relevant knowledge for characterising an important taxonomic group in an area with relatively few biodiversity studies. Occurrence data from the Global Biodiversity Information Facility (GBIF) and bioclimatic variables from the WorldClim database were used as input for species distribution modelling (SDM). Due to the low number of available occurrence data resulting in inconsistent performance of different tools, several algorithms implemented in the DISMO package in R (Bioclim, Domain, GLM, Mahalanobis, SVM, RF and MaxEnt) were tested to determine which provide the best performance. Occurrence sets at several distribution densities were tested to determine which algorithm and sample size combination provided the best model results. The machine learning algorithms RF, SVM and MaxEnt consistently provided the best performance as evaluated by the True Skill Statistic (TSS), Kappa and Area Under Curve (AUC) metrics. The occurrence set with a density distribution of one sampling point per 10km2 provided the best performance and was used for the final prediction model. An ensemble of the best-performing algorithms generated the final suitability predictive map. The results can serve as a basis for additional studies and provide initial information that will eventually support decision-making processes supporting conservation in the archipelago.

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  • Queensland fruit fly invasion of New Zealand : predicting area suitability under future climate change scenarios

    Aguilar, Glenn; Blanchon, Dan; Foote, Hamish; Pollonais, Christina; Mosee, Asia (2015-10-07)

    Journal article
    Unitec

    The Queensland fruit fly Bactrocera tryoni (Froggatt) (Diptera: Tephritidae) is consistently described as the most damaging pest to Australia’s horticulture industries with an annual economic cost averaging around $25.7 million from 2003 to 2008 . In this paper, and corresponding online map, the authors discuss the significant risk to New Zealand of invasion by this species; the potential effects of climate change on the distribution and impacts of invasive species are well known. This paper and eMedia employs species distribution modelling using Maxent to predict the suitability of New Zealand to the Queensland fruit fly based on known occurrences worldwide and Bioclim climatic layers.

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  • Modelling invasions : use of species distribution models (SDM)

    Aguilar, Glenn (2015-11)

    Conference item
    Unitec

    Species distribution modelling • Also called: – species distribution modeling – ecological niche modelling – climate envelope modeling • Predict geographic distribution based on ecological niche or environmental distribution • Identify areas in a landscape with similar environments to localities where the species has been located or observed

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  • Geographic Information Systems (GIS), geo-information and apps: using the workflow approach to optimize solutions for your mapping needs

    Aguilar, Glenn (2015-07)

    Conference item
    Unitec

    A Good Workflow ensures efficient GIS projects Modelling is good but accurate field data is critical (1989): Area management cannot be done sensibly without GIS (2006) There is a lot of spatial data available but a lot of work is needed to convert them to useful maps (2011), (2013) Maps and GIS outputs: best way to convey issues and solutions (2013, 2014,2015); Rapid progress in spatial data acquisition and visualization A Good Workflow ensures efficient GIS projects

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  • Mapping the potential range of the brown marmorated stink bug in New Zealand

    Aguilar, Glenn; Fraser, Diane; Kumar, Shivani (2016-07)

    Conference item
    Unitec

    Aim and Objectives: Predict the suitability of New Zealand to the BMSB Ensemble the predictions of best performing Species Distribution Modelling algorithms using worldwide occurrence of BMSB and environmental data Project the model into New Zealand using current and future climate scenarios

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  • Stray cats in Auckland, New Zealand: Discovering geographic information for exploratory spatial analysis

    Farnworth, Mark; Aguilar, Glenn (2012)

    Journal article
    Unitec

    Stray cats are a common feature of urban landscapes and are associated with issues of animal welfare and negative environmental impacts. Management, planning and decision-making require readily accessible information on stray cats. However, much of the existing data is not immediately useful for a geographic information system (GIS) in terms of format, content and explicit location information. Spreadsheets we obtained from a single large shelter in the Auckland region. They contained records of stray cat pickups and admissions for an entire year (n = 8573) of which 56.4% (n = 4834) contained data that could be processed to derive relevant spatial information. The resulting data consisted of identified roads and areas of Auckland where the stray cats were found. Published census databases and shapefiles were matched with the data to build a GIS of stray cats. Global and local regression analysis was employed to discover spatial distribution characteristics including the identification of areas with relatively high and low concentrations of stray cats and to explore relationships between socioeconomic condition and stray cat density. Significant clustering is more evident in South Auckland than elsewhere in the region. Specific geographical information is valuable, not only for understanding population dynamics of stray cats, but also to allow spatial and temporal targeting of resources to minimise their impact and promote responsible ownership.

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  • GIS research for biodiversity management and animal welfare

    Farnworth, Mark; Aguilar, Glenn; Fraser, Diane; Galbraith, Mel (2011-10)

    Conference item
    Unitec

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  • Development of GIS learning objects for an enhanced conceptual understanding and skills development of complex computing tasks

    Aguilar, Glenn (2011-10)

    Conference item
    Unitec

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  • Focus on Fiji: GIS Mapping to Support Conservation Planning

    Winder, Linton; Aguilar, Glenn (2013)

    Unclassified
    Unitec

    In collaboration with the Institute of Applied Science of the University of the South Pacific in Suva, Fiji, the project conducted research on the development of a Geographic Information System for biodiversity conservation, development planning and environmental management. The objectives of the research include the characterization of the spatial distribution of key organisms that are of conservation interest, the determination of the effects of environmental perturbations such as climate change and contributing models that support mitigation strategies and conservation prioritization.

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  • Changes in the breeding status of the southern black-backed gull (Larus dominicanus) colonies on Rangitoto Island, Hauraki Gulf, New Zealand

    Galbraith, Mel; Krzyżosiak, Jacek; Aguilar, Glenn; Jones, Graham; Oliver, Rob (2015)

    Journal article
    Unitec

    The southern black-backed gull (Larus dominicanus) is a common species throughout New Zealand, and has a significant presence in Auckland City. Large colonies are present on Rangitoto Island only 8 km from the city’s centre. The proximity of these colonies to the anthropogenic resources of the city may have influenced breeding locations and local populations. Using field data from the 2012/13 breeding period, we compare the current status of the breeding population on Rangitoto Island with historical data collated from literature. The Rangitoto population exhibited rapid growth throughout the early 20th century, a pattern attributed to environmental changes associated with European settlement and development. Since the 1980s, the colony sizes have declined, a change that is consistent with other gull populations both nationally and globally. The driver of the population changes is likely to be the availability of food and the expansion of vegetation into the colonies. Human disturbance and predation are discounted as impacting on population change.

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  • The house crow (Corvus splendens): a threat to New Zealand?

    Fraser, Diane; Aguilar, Glenn; Nagle, William; Galbraith, Mel; Ryall, Colin (2015-05-04)

    Unclassified
    Unitec

    The house crow (Corvus splendens), a native of the Indian subcontinent, has shown a rapid expansion of habitat range across Eastern Africa, the Arabian Peninsula, Europe and Asia. It is an adaptable, gregarious commensal bird which is regarded globally as an important pest species due to its impacts on livestock, agricultural and horticultural crops and indigenous fauna and as a fecal contaminator of human environments and water resources. Two Maxent (v3.3.3k) models (A) with presence data in Australia and (B) with simulated entry data locations in New Zealand) and a third ArcGIS model (C) with environmental and social layers) are used to determine an overall suitability index and establish a niche-based model of the potential spatial distribution for C. splendens within New Zealand. The results show that New Zealand, particularly the northern regions of North Island, has suitable environments for the establishment of the house crow. In order of suitability Model B showed highest potential land area suitability (31.84%) followed by Model A (13.79%) and Model C (10.89%). The potential for further expansion of this bird’s invasive range is high and, if New Zealand is invaded, impacts are likely to be significant.

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  • Distribution of Argentine ant (Linepithema humile) and Rainbow skink (Lampropholis delicata) in selected locations in the Rodney district, Auckland

    Marshall, Andrew; Cook, Jeff; Waipara, Nick; Aguilar, Glenn; Galbraith, Mel; Fraser, Diane (2014)

    Conference item
    Unitec

    Distribution maps of areas where present.

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  • Comparison of species richness and frequency cover of forest floor plants and lichens in sites invaded and uninvaded by the invasive club moss Selaginella kraussiana (Kunze) A. Braun.

    Nessia, Hayley R.; Dale, Arnja; Perrott, John; Waipara, Nick W.; Aguilar, Glenn; Blanchon, Dan (2014-10-14)

    Journal article
    Unitec

    Selaginella kraussiana, or the African club moss, is a fern ally in the family Selaginellaceae invasive to several countries including New Zealand. This study was carried out to compare species richness and frequency cover in adjacent forest floor botanical communities with and without S. kraussiana using a paired experimental design. Sites with S. kraussianahad reduced species richness, particularly the number of conifer and flowering plant species.Frequency cover (excluding S. kraussiana) was not significantly affected.

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  • Distribution characteristics of unmanaged cat colonies over a 20 year period in Auckland, New Zealand

    Aguilar, Glenn; Farnworth, Mark (2013)

    Journal article
    Unitec

    Cat colony records for the period 1991 to 2011 were used to determine spatial characteristics and relationships between cat colony density, human population, social conditions and the physical envi- ronment. Results show a positive correlation between cat colonies, population density, social indicators and the types of land where they are located. A temporal increase in the density of cat colonies is noticeable in areas where they are frequently reported, supporting the hypothesis that cat colonies are a persistent feature of Auckland’s urban landscape. Complementing an earlier paper on stray cats, this paper seeks to provide information to support the implementation of management measures to mitigate both social and animal welfare concerns

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  • Monitoring terrestrial bird populations on Tiritiri Matangi Island, Hauraki Gulf, New Zealand, 1987-2010

    Graham, Mike; Veitch, Dick; Aguilar, Glenn; Galbraith, Mel (2013-11-18)

    Unclassified
    Unitec

    Tiritiri Matangi Island is a Scientific Reserve located in the Hauraki Gulf, New Zealand. In 1986, two years after the start of a ten-year planting programme on the island, members of the Ornithological Society of New Zealand, Auckland, began a monitoring programme of the bird populations. A biannual survey scheme commenced in April 1987, counting birds on predetermined transects and at listening posts. This paper focuses on the spring dataset (November) to provide an overview of changes in relative abundance of birds from 1987 to 2010. Over this time, a revegetation programme, the successful translocation of 11 native bird species to the island and eradication of kiore (Pacific rat Rattus exulans) have altered the dynamics of the environment. Overall, an increase in indigenous avian biodiversity and abundance was recorded, although the increase was dominated by two species, the tui (Prosthemadera novaeseelandiae) and bellbird (Anthornis melanura). Substantial increases in population abundance were observed in the translocated species recorded in the counts. Exotic species and common forest passerines (fantail Rhipidura fuliginosa, grey warbler Gerygone igata, silvereye Zosterops lateralis) declined. Some of the possible reasons for these changes are discussed.

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  • Distribution characteristics of unmanaged cat colonies over a 20 year period in Auckland, New Zealand

    Aguilar, Glenn; Farnworth, Mark (2013)

    Journal article
    Unitec

    Cat colony records for the period 1991 to 2011 were used to determine spatial characteristics and relationships between cat colony density, human population, social conditions and the physical environment. Results show a positive correlation between cat colonies, population density, social indicators and the types of land where they are located. A temporal increase in the density of cat colonies is noticeable in areas where they are frequently reported, supporting the hypothesis that cat colonies are a persistent feature of Auckland’s urban landscape. Complementing an earlier paper on stray cats, this paper seeks to provide information to support the implementation of management measures to mitigate both social and animal welfare concerns.

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