Browsing by Author "Robertson A"

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    Characterisation of New Zealand Propolis from Different Regions Based on Its Volatile Organic Compounds
    (MDPI (Basel, Switzerland), 2024-07-02) Mountford-McAuley R; Robertson A; Taylor M; Clavijo McCormick A; Falcão SI
    Propolis is a bee product mainly consisting of plant resins and is used by bees to maintain the structural integrity of the colony. Propolis is known to contribute to bee health via its antimicrobial activity and is a valued product for human use owing to its nutritional and medicinal properties. Propolis is often characterised into seven categories depending on the resin source. New Zealand propolis is typically assumed as being poplar-type propolis, but few studies have chemically characterised New Zealand propolis to confirm or reject this assumption. Here, for the first time, we characterise propolis originating from different regions in New Zealand based on its volatile organic compounds, using gas chromatography coupled with mass spectrometry (GC-MS). To support this characterisation, we also collected and analysed resin samples from a variety of resin-producing plants (both native to New Zealand and introduced). Our findings suggest that bees mainly use poplar as a resin source, but also utilize native plant species to produce propolis. While regional variation did not allow for clear separation between samples, some patterns emerged, with samples from some regions having more chemical complexity and a higher contribution from native species (as suggested by a higher number of compounds unique to native species resin). Further studies are needed to accurately identify the botanical sources contributing to these samples. It may be also of interest to explore the biological activity of regional propolis samples and their potential nutritional or medicinal benefits.
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    Not All Birds of the Same Feather: A Systematic Review of Ecosystem Services and Disservices in Horticulture
    (John Wiley and Sons Australia, Ltd on behalf of Ecological Society of Australia, 2025-09-01) Ferrari GCP; Mason K; Robertson A; Castro I
    Wild birds can provide essential benefits and cause significant harm in food production systems, commonly framed as ecosystem services and disservices, respectively. We conducted a systematic review of the literature on avian ecosystem services and disservices in horticultural systems, analysing 251 studies published between 1912 and 2023. Species richness and abundance were the most commonly used metrics. A total of 128 studies investigated ecosystem services, 109 addressed disservices, and only 22 considered both. Pest control (137 occurrences) and crop damage (120) were the dominant subjects within ecosystem services and disservices, respectively. However, crop damage was frequently reported without assessment, suggesting a confirmation bias towards birds as pests. The methods used to assess services and disservices were diverse, including species identification, damage and yield surveys, landscape analysis, experiments, published data, social surveys, laboratory techniques, and economic or ecological modelling. Despite this methodological diversity, most studies used only one or two approaches. Studies incorporating human-wildlife conflict were rare, despite their relevance for both conservation and horticultural management. This review reveals a bias towards studying avian contributions that are more easily measurable, such as pest control and crop damage, while more complex or less visible effects, such as pollination, disease control, or herbivore release, remain underexplored. As a result, birds' roles in horticultural systems are often understood in fragmented terms, potentially leading to ineffective or unjustified management decisions. A more holistic, species-focused, and integrative approach is needed to fully understand the trade-offs between ecosystem services and disservices. Such understanding is critical not only for enhancing the sustainability and productivity of food systems, but also for conserving wild birds in increasingly intensified agricultural landscapes.