title: Understanding acceptable level of risk: Incorporating the economic cost of under-managing invasive species

authors: Davidson, Alisha D.

abstract: Management of nonindigenous species includes prevention, early detection and rapid response and control. Early detection and rapid response depend on prioritizing and monitoring sites at risk for arrival or secondary spread of nonindigenous species. Such monitoring efforts require sufficient biosecurity budgets to be effective and meet management or policy directives for reduced risk of introduction. Such consideration of risk reduction is rarely considered, however. Here, we review the concepts of acceptable level of risk (ALOR) and associated costs with respect to nonindigenous species and present a framework for aligning risk reduction priorities with available biosecurity resources. We conclude that available biosecurity resources may be insufficient to attain stated and desired risk reduction. This outcome highlights the need to consider policy and management directives when beginning a biosecurity program to determine the feasibility of risk reduction goals, given available resources.

text: Understanding acceptable level of risk: Incorporating the economic cost of under-managing invasive species Management of nonindigenous species includes prevention, early detection and rapid response and control. Early detection and rapid response depend on prioritizing and monitoring sites at risk for arrival or secondary spread of nonindigenous species. Such monitoring efforts require sufficient biosecurity budgets to be effective and meet management or policy directives for reduced risk of introduction. Such consideration of risk reduction is rarely considered, however. Here, we review the concepts of acceptable level of risk (ALOR) and associated costs with respect to nonindigenous species and present a framework for aligning risk reduction priorities with available biosecurity resources. We conclude that available biosecurity resources may be insufficient to attain stated and desired risk reduction. This outcome highlights the need to consider policy and management directives when beginning a biosecurity program to determine the feasibility of risk reduction goals, given available resources.

year: 2015

title: Development of a Rhizosheath Selection Tool for screening perennial ryegrass (Lolium perenne L.) for reduced root competition against white clover (Trifolium repens L.) for soil phosphorus

authors: Yeates, Rebecca Maree

subjects: Agriculture

abstract: Perennial ryegrass (Lolium perenne L.) outcompetes white clover (Trifolium repens L.) for soil phosphorus [P], resulting in higher P fertiliser rates to overcome the competition. Perennial ryegrass has long, dense root hairs compared to white clover, which increase the root contact with soil (soil exploration) and root surface area for P uptake. This study was conducted to test whether the selection of perennial ryegrass with reduced root hair length and density would reduce root competition for P with no detrimental effect on the perennial ryegrass growth. 
A Rhizosheath Selection Tool [RST] was developed to select ryegrass populations with contrasting root hair length and density. The RST protocol used rhizosheath traits (the width and coverage of soil adhered to the extracted root system) along with the total seedling weight to select two distinct ryegrass populations. The low rhizosheath population had shorter, sparser root hairs on seminal roots and sparser root hairs on adventitious roots than the high rhizosheath population.
The two populations were then grown at five soil P levels in a glasshouse experiment and demonstrated that the rhizosheath trait selection had no detrimental effect on growth. There were no significant differences between the two population’s dry weight (g) and P concentration (mg P g-1 dry weight). However there was evidence to indicate that the high rhizosheath population was sometimes more efficient at P uptake with a larger total P content (mg P). 
The two perennial ryegrass populations were then grown with companion white clover in Olsen P 12 and 19 mg L⁻¹ soil with partitions separating the shoot systems to avoid shoot competition for light. The low rhizosheath population had reduced root competition with the companion white clover. In Olsen P 12 mg L⁻¹ soil, more P was partitioned to the white clover than the ryegrass, measured by total P content (mg P), and achieved a greater dry weight (g) than when grown with the HRS ryegrass. In Olsen P 19 mg L⁻¹ soil there was no rhizosheath selection effect on white clover growth, possibly because of the reduced need for soil exploration by roots under the higher soil P availability. 
The findings from this study confirmed that the RST for the selection of a perennial ryegrass population with a reduced capacity for root competition against white clover for soil P is effective. Furthermore, the RST selection had no detrimental effect to the ryegrass growth. This research highlights the importance of root traits in forage plant breeding, and the potential environmental and economic benefits a low rhizosheath perennial ryegrass could have in New Zealand’s pastoral farming system.

text: Development of a Rhizosheath Selection Tool for screening perennial ryegrass (Lolium perenne L.) for reduced root competition against white clover (Trifolium repens L.) for soil phosphorus Perennial ryegrass (Lolium perenne L.) outcompetes white clover (Trifolium repens L.) for soil phosphorus [P], resulting in higher P fertiliser rates to overcome the competition. Perennial ryegrass has long, dense root hairs compared to white clover, which increase the root contact with soil (soil exploration) and root surface area for P uptake. This study was conducted to test whether the selection of perennial ryegrass with reduced root hair length and density would reduce root competition for P with no detrimental effect on the perennial ryegrass growth. 
A Rhizosheath Selection Tool [RST] was developed to select ryegrass populations with contrasting root hair length and density. The RST protocol used rhizosheath traits (the width and coverage of soil adhered to the extracted root system) along with the total seedling weight to select two distinct ryegrass populations. The low rhizosheath population had shorter, sparser root hairs on seminal roots and sparser root hairs on adventitious roots than the high rhizosheath population.
The two populations were then grown at five soil P levels in a glasshouse experiment and demonstrated that the rhizosheath trait selection had no detrimental effect on growth. There were no significant differences between the two population’s dry weight (g) and P concentration (mg P g-1 dry weight). However there was evidence to indicate that the high rhizosheath population was sometimes more efficient at P uptake with a larger total P content (mg P). 
The two perennial ryegrass populations were then grown with companion white clover in Olsen P 12 and 19 mg L⁻¹ soil with partitions separating the shoot systems to avoid shoot competition for light. The low rhizosheath population had reduced root competition with the companion white clover. In Olsen P 12 mg L⁻¹ soil, more P was partitioned to the white clover than the ryegrass, measured by total P content (mg P), and achieved a greater dry weight (g) than when grown with the HRS ryegrass. In Olsen P 19 mg L⁻¹ soil there was no rhizosheath selection effect on white clover growth, possibly because of the reduced need for soil exploration by roots under the higher soil P availability. 
The findings from this study confirmed that the RST for the selection of a perennial ryegrass population with a reduced capacity for root competition against white clover for soil P is effective. Furthermore, the RST selection had no detrimental effect to the ryegrass growth. This research highlights the importance of root traits in forage plant breeding, and the potential environmental and economic benefits a low rhizosheath perennial ryegrass could have in New Zealand’s pastoral farming system.

year: 2018

title: Mōteatea: He pātaka whakairinga kōrero nō Ngāti Rangiwewehi

authors: Paterson, Awatea

subjects: Ngāti Rangiwewehi

abstract: Mai rā anō a Ngāi Tāua, te iwi Māori, e tuku iho ai i ngā mātauranga mā te ārero tupuna mai i tētehi whakatupuranga, ki tētehi whakatupuranga. Ko ngā mātauranga ka tukua iho ko ngā pūrākau, ko ngā karakia, ko ngā whakataukī, ā, ko ngā waiata hoki. Ko te pūtake o te rangahau nei he titiro pū ki te āhua o te noho o ngā mōteatea hei pātaka whakairinga kōrero mō Ngāti Rangiwewehi ake, nō reira ka āta tirohia ngā momo puna mōhiohio, ngā momo kura aweko ka whakairia ki te pakitara o te pātaka kōrero o Ngāti Rangiwewehi. Nā ngā mōteatea i tohu te wā, i kōrero mō te wāhi, i whakapūkete ngā mahi a ngā tūpuna o te wā i titoa ai te mōteatea. Nā, ko ngā waiata, ko ngā mōteatea koirā te ara whakapūkete kōrero ka wānangahia e te tuhinga nei. Mā te āta wetewete i tētehi mōteatea pū o Ngāti Rangiwewehi, ka hora i ngā kura āuki, i ngā māpihi pounamu, i ngā puna mātauranga o te iwi kua whakaemi mai ki roto i te mōteatea hei kōrero tuku iho mō te iwi o Ngāti Rangiwewehi, hei whakatauira ake hoki i te āhua o te noho o ngā mōteatea hei ara whakapūkete mātauranga.

text: Mōteatea: He pātaka whakairinga kōrero nō Ngāti Rangiwewehi Mai rā anō a Ngāi Tāua, te iwi Māori, e tuku iho ai i ngā mātauranga mā te ārero tupuna mai i tētehi whakatupuranga, ki tētehi whakatupuranga. Ko ngā mātauranga ka tukua iho ko ngā pūrākau, ko ngā karakia, ko ngā whakataukī, ā, ko ngā waiata hoki. Ko te pūtake o te rangahau nei he titiro pū ki te āhua o te noho o ngā mōteatea hei pātaka whakairinga kōrero mō Ngāti Rangiwewehi ake, nō reira ka āta tirohia ngā momo puna mōhiohio, ngā momo kura aweko ka whakairia ki te pakitara o te pātaka kōrero o Ngāti Rangiwewehi. Nā ngā mōteatea i tohu te wā, i kōrero mō te wāhi, i whakapūkete ngā mahi a ngā tūpuna o te wā i titoa ai te mōteatea. Nā, ko ngā waiata, ko ngā mōteatea koirā te ara whakapūkete kōrero ka wānangahia e te tuhinga nei. Mā te āta wetewete i tētehi mōteatea pū o Ngāti Rangiwewehi, ka hora i ngā kura āuki, i ngā māpihi pounamu, i ngā puna mātauranga o te iwi kua whakaemi mai ki roto i te mōteatea hei kōrero tuku iho mō te iwi o Ngāti Rangiwewehi, hei whakatauira ake hoki i te āhua o te noho o ngā mōteatea hei ara whakapūkete mātauranga.

year: 2013