Mackay, Keith David

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Given Name
Keith David
David
Surname
Mackay
UNE Researcher ID
une-id:kmackay5
Email
kmackay5@une.edu.au
URI
Preferred Given Name
David
School/Department
School of Environmental and Rural Science

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    Publication
    Differential impacts of fire and inundation on a wetland plant community after wildfire
    (CSIRO Publishing, 2024-10-16)
    Mackay, K D 
    ;
    Vincent, B 
    ;
    Southwell, M 
    ;
    Growns, I 
    ;
    Mika, S 

    Context. Understanding fire and inundation impacts on wetland vegetation communities is crucial for effective post-fire wetland management. Aims. We aimed to determine the impact of post-fire inundation on plant community structure and seedling germination and establishment after a large wildfire. We asked two questions, namely (1) did fire, drought or inundation affect plant communities the most; and (2) did fire or inundation affect seedling germination and establishment? Methods. Using a before–after–control–impact (BACI) design, we monitored vegetation changes in water-couch wetland communities before and after a wildfire. Also, soil samples were collected from burnt and unburnt sites and assessed for impacts of fire and post-fire inundation regimes on seed germination and seedling establishment. Key results. Inundation variables had more pronounced and more consistent impacts on vegetation measures than did fire or drought variables. Fire impacts were mainly short-term, with impact thresholds at 72 and 143 days after fire. Low germination levels and zero seedling survival were observed without inundation. Conclusions. Fire was a major but short-term contributor to wetland vegetation change, whereas drought had longer-term impacts, and inundation regimes had the greatest impacts. Implications. Providing a range of inundation conditions post-fire may enhance wetland vegetation recovery and have modifying effects on invasive species.

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    Publication
    Fatal attraction - the predation of pollinators leads to reproductive conflict in pollen limited populations of Drosera hookeri (Droseraceae) - Dataset
    (University of New England, 2023-04-04)
    Gross, Caroline 
    ;
    Whitehead, Joshua 
    ;
    Mackay, Keith David 
    ;
    Water, Wendy A
    ;
    Silveira de Souza, C
    Pollinator-prey conflict in carnivorous plants occurs when plants that benefit from pollinators are pollen-limited and pollinators are snared by trap-leaves. To date a strong pollinator-prey conflict has not been found and is attributed to spatial and/or cue differences between flowers and traps abating conflict. Here we test whether pollinator-prey conflict occurs for Drosera hookeri (Droseraceae), which produces entomophilous flowers adjacent to leaf-traps. We also test the hypothesis that flowers have a dual role of pollinator attraction and deception by tumbling pollinators and other floral visitors into leaf-traps. From 2007-2021, in a drought-prone habitat in eastern Australia, pollinator diversity and visitation rates were scored at flowers using camcorders while pan-traps provided an estimate of pollinator abundance in the community. Hand-pollination experiments were used to determine pollinator dependence and pollen limitation. We also measured arthropod abundance in trap-leaves before, during and after flowering. In a paired experiment we compared leaf captures between plants with and without flowers to determine if flowers are complicit in the leaf captures of pollinators. Although self-compatible, with a delayed selfing-mechanism, outcrossed flowers produced more seed than self-pollinated flowers, indicating that pollinators are beneficial. Plants were pollen-limited in both years tested. Flies (non-pollinating and pollinating) were the most common prey with the greatest numbers during peak flowering. Pollinators, predominantly Melangyna virdiceps (Syriphidae, Diptera), contributed c. 57% of prey captures, and experimentally we show that they are not attracted to plants without flowers. Pollinators are often deposited into trap-leaves from flowers, which tip under their weight, to nearby leaf traps. A strong pollinator-prey conflict was detected with an overlap in prey and pollinators in a pollen and pollinator-limited system. Flowers attract pollinators and non-pollinators to plants. Leaf entrapment for pollinators occurs as a mishap in foraging rather than attraction to trap-leaves. The flowers in D. hookeri have the dual role of pollination and prey provision.