Browsing by Author "Burkitt LL"

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    An integrative approach to silvopastoral system design: perspectives, potentials and principles
    (Informa UK Limited, trading as Taylor & Francis Group, 2024-01-01) Mackay-Smith TH; Spiekermann RI; Richards DR; Harcourt N; Burkitt LL
    Silvopastoral systems have complex impacts on a diverse range of outcomes, making it essential to design these systems using an integrative approach to maximise positive impacts to farms. This paper comprises firstly a systematic review of global silvopastoral processes, and secondly stakeholder-driven synthesis of key opportunities and challenges for future silvopastoralism situated in the context of New Zealand. The systematic review demonstrated that although under-researched, livestock interactions can have overriding influences on the system, and that the traditional functional traits that are typically deemed important for selection (N2-fixing trees v non N2-fixing trees, evergreen v deciduous) do not show consistent positive impacts on the agroecological environment. From the New Zealand silvopastoral participatory case study, including the stakeholder workshop, we synthesised 5 key principles that should be considered in future system designs. These were: (1) silvopastoral systems are complex and require holistic management; (2) the views, values and experiences of local people are deeply connected to silvopastoral system design; (3) spatial heterogeneity in environmental and social conditions requires locally specific decisions; (4) understanding of ecological processes must underpin all management decisions; and (5) the complexity and spatial heterogeneity present in silvopastoral systems requires high-resolution data and tools.
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    Kānuka Trees Facilitate Pasture Production Increases in New Zealand Hill Country
    (MDPI (Basel, Switzerland), 2022-07) Mackay-Smith TH; López IF; Burkitt LL; Reid JI
    ‘Tree-pasture’ silvopastoral systems have the potential to become transformative multifunctional landscapes that add both environmental and economic value to pastoral farms. Nevertheless, no published study has found increased pasture production under mature silvopastoral trees in New Zealand hill country. This study takes a novel approach to silvopastoral research in New Zealand, and investigates a genus that has similar bio-physical attributes to other global silvopastoral trees that have been shown to increase pasture production under their canopies, with the aim of finding a silvopastoral genera that can increase pasture production under tree canopies compared to open pasture in New Zealand. This study measures pasture and soil variables in two pasture positions: under individually spaced native kānuka (Kunzea spp.) trees (kānuka pasture) and paired open pasture positions at least 15 m from tree trunks (open pasture) at two sites over two years. There was 107.9% more pasture production in kānuka pasture positions. The soil variables that were significantly greater in kānuka pasture were Olsen-P (+115.7%, p < 0.001), K (+100%, p < 0.001), Mg (+33.33%, p < 0.01), Na (+200%, p < 0.001) and porosity (+8.8%, p < 0.05), and Olsen-P, porosity and K best explained the variation between kānuka pasture and open pasture positions. Volumetric soil moisture was statistically similar in kānuka pasture and open pasture positions. These results are evidence of nutrient transfer by livestock to the tree-pasture environment. Furthermore, as there was a significantly greater porosity and 48.6% more organic matter under the trees, there were likely other processes also contributing to the difference between tree and open pasture environments, such as litterfall. These results show that kānuka has potential to increase pasture production in New Zealand hill country farms and create multifunctional landscapes enhancing both production and environmental outcomes in pastoral farms.
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    Pasture production–diversity relationships in a kānuka silvopastoral system
    (John Wiley & Sons Ltd on behalf of British Ecological Society, 2023-04-09) Mackay-Smith TH; López IF; Burkitt LL; Reid JI; Wagg C
    Silvopastoral systems have great potential for forming multifunctional landscapes that provide a range of economic and environmental benefits to pastoral land. However, pasture production–diversity relationships in silvopastures require further exploration. This study measures how pasture functional group production, pasture species diversity and pasture functional diversity (FD) are impacted by trees in a novel native silvopastoral system in New Zealand hill country with kānuka (Kunzea spp.). Silvopastoral trees facilitated the growth of fast-growing competitor functional groups (Lolium perenne, Dactylis glomerata and high fertility annuals: Bromus hordeaceus and Critesion murinum), because of positive impacts on soil fertility, organic matter and porosity. Shannon diversity, species richness and species evenness were significantly less in the more productive pastoral environment under the trees, but functional richness, functional evenness and functional dispersion were similar between kānuka pasture and open pasture. These results show that silvopastures can increase pasture production by promoting the growth of competitive pasture functional groups, and that reduced species diversity under silvopastoral trees does not necessarily impact FD in the context of production. Moreover, species indices overestimated diversity reductions under the trees compared to functional indices. Thus, considering FD in silvopastoral systems is integral for not misinterpreting diversity outcomes.