Zealand Plants Research Articles

Microbial signatures of vertebrate visitation in floral nectar: a case study with two endemic Aotearoa New Zealand plant species

ABSTRACT Microbes found in nectar and dispersed by animal visitors can mediate pollination and host fitness. While previous studies have characterised floral nectar microbiomes and their effects on invertebrate pollinators, fewer studies have focused on vertebrate pollinators, especially outside of the Northern Hemisphere. In Aotearoa New Zealand, vertebrates, such as birds and bats, are critical pollinators for many native plant species. Here, we present nectar microbiome profiles for two endemic, vertebrate-pollinated plant species in Aotearoa New Zealand, wharariki, mountain flax (Phormium cookianum), and pua o te Rēinga, wood rose (Dactylanthus taylorii). We used vertebrate exclusion treatments and camera traps to monitor visitation. Camera trap footage revealed silvereye (Zosterops lateralis), ship rat (Rattus rattus), and possum (Trichosurus vulpecula) visitation. We detected shifts in microbial species turnover in wood rose and varying relative abundances of fungal and bacterial taxa across the vertebrate exclusion treatments for both mountain flax and wood rose. However, we did not detect strong effects on floral nectar microbiome community composition or richness. Future work should move beyond profiling the microbial communities and identify fitness consequences and pollination outcomes, which could affect conservation and management decisions.

From control to sustainability: 75 Years of the New Zealand Plant Protection Society

This editorial summarises the first 75 years of the New Zealand Plant Protection Society. The structure of the Society and approaches to plant protection have changed over the years but the essence of the original vision to bring together industry, government, and university researchers, to ‘pool and exchange information’, is still relevant today.

Lepra erythrella (Pertusariaceae) – a new addition to the lichenized mycobiota of the Aotearoa / New Zealand archipelago

An investigation of the flora, mycobiota and lichenized mycobiota associated with the endemic Aotearoa / New Zealand plant genus Lophomyrtus (Myrtaceae) revealed a specimen of Lepra erythrella (Pertusariaceae). Lepra erythrella, though briefly mentioned in a paper documenting the results of that Lophomyrtus study, has not yet been formally admitted into the lichenized mycobiota of Aotearoa / New Zealand. Therefore, to complete that process in this paper, we provide a description based on the collection made from Lophomyrtus and a further one located in the Allan Herbarium (CHR). The addition of Lepra erythrella to the lichenized biota of Aotearoa / New Zealand highlights not only the lack of collecting of this genus in that archipelago but the need to critically examine that nation’s herbarium collections. We recommend that further research on this genus is carried out in our region.

New Zealand divaricate plant species: Tensile strength and Remote Island occurrence

AbstractDivaricate plant species account for more than 10% of New Zealand/Aotearoa's woody flora, a higher proportion for that life form than anywhere else on earth. Two main hypotheses have been proposed to account for the prevalence of this phenotype. The first suggests herbivorous birds, particularly large flightless moa, exerted selective pressure on many plants to adopt the form. The second proposes climate as the main driver since insular New Zealand has many exposed habitats and, historically, experienced stressing conditions during the Pleistocene. Our study investigated two questions to shed further light on the evolution of divaricates, in particular related to the potential influence of browsing by large avian herbivores. First, divaricate plants have been posited to have a higher tensile strength than non‐divaricates as a defence mechanism against moa browsing. We tested the great majority of New Zealand plant genera within which divaricates occur, contrasting the stem tensile strength of these plants against their closest non‐divaricate counterparts using accurate testing technology. The results indicate divaricate species have tensile strength that approaches twice that of non‐divaricates across a broad and disparate phylogenetic range that includes gymnosperms and many clades of angiosperms. Second, we tested the species level distributions of widely dispersed woody plant genera across the New Zealand archipelago on islands where moa had been present or always absent. We found that no endemic divaricate species occurred on any islands from which moa had been permanently absent. In contrast, their non‐divaricate counterparts were commonly endemic to those same islands.

Inferring the biogeography of New Zealand’s only endemic holoparasitic plant, the threatened Dactylanthus taylorii (Mystropetalaceae)

ABSTRACT Despite a rich history of botanical research, little is known about the distribution of genetic variation within New Zealand plant species. With a native vascular flora that consists of ∼80% endemics, nearly one-half of which are threatened, there is a dire need for a better understanding of intraspecific diversity for individual plant species and of biogeographic patterns for the wider New Zealand flora. To these ends, we have investigated population genetic structure in the endemic root holoparasite, Dactylanthus taylorii (pua o te Rēinga, Mystropetalaceae). A total of 235 individuals from 31 locations across the North Island of New Zealand (Te Ika-a-Māui, Aotearoa) were genotyped for a suite of nuclear microsatellite loci. Genotype data were analysed at the individual and population levels to assess genetic diversity within and among populations and to investigate the geographic distribution of genetic variation within the species. Population structure was assessed using Bayesian clustering, discriminant analysis of principal components, and a Neighbor-Net analysis. A hierarchical pattern of genetic diversity was revealed, with evidence for three broad geographic regional groupings (West, East, and Central Volcanic Plateau (CVP)). Upon further analysis, each of the three geographic groups further subdivide hierarchically into two or three genetic subgroups. Genetic diversity was found to be relatively high in this endangered species but varies considerably across populations. The distribution of genetic groups appears to have been influenced by past volcanic activity as the CVP group is largely coincident with a distinct tephra isopach from the 1.8 ka Taupō eruption and the West and East groups may have diverged due to recurring volcanic activity in the Central Volcanic Zone. The genetic structure resolved here provides important information for the management of D. taylorii specifically and for our understanding of New Zealand biogeography generally.

Plastid genome sequences are consistent with introduction of Phormium tenax to Norfolk Island and Chatham Islands by early East Polynesian voyagers but not vicariance explanations

ABSTRACT Phormium tenax (harakeke, New Zealand flax: Asphodelaceae) has long been considered indigenous to New Zealand (including the Chatham Islands) and Norfolk Island. However, the indigeneity of P. tenax on Norfolk Island, in particular, has been challenged by an alternative hypothesis that it was introduced by East Polynesians prior to European colonisation. We tested this alternative hypothesis using a dated phylogenetic tree. We also tested whether dated phylogenetic trees of Phormium could be reconciled with vicariance explanations of its distribution. We examined near-complete plastid genome sequences of P. tenax, P. cookianumand related plants. We then undertook Bayesian and likelihood estimation of the age of the divergence between Norfolk Island and New Zealand accessions using fossil calibration, and separately using biogeographic calibration assuming vicariance explanations of trans-oceanic distributions. DNA sequences of Norfolk Island plants were invariant and nested well within the wider diversity of P. tenax. Estimates of divergence times using fossil calibration did not exclude a common ancestor as recent as the second millennium CE. DNA sequences of Chatham Islands P. tenax were also nested within the diversity of P. tenax from New Zealand, but age estimates were older for their divergence from New Zealand plants (around 20,000–400,000 years). Biogeographic calibrations resulted in extremely ancient ages (tens of billions of years) of deeper nodes within the tree or several orders of magnitude variation in rates among lineages. Our results are consistent with translocation of harakeke by East Polynesian people, but our analyses cannot exclude a Late Quaternary natural dispersal event, which might result in similar genetic patterns. Biogeographic calibrations based on the break-up of Gondwana imply major departures from contemporary ideas of Earth's history, or orders of magnitude rate variation among lineages.

Taxonomic and nomenclatural novelties in Syntrichia (Bryophyta: Pottiaceae), with reinstatement of an endemic continental Antarctic species

Taxonomic implications of the phylogeographic studies based on multilocus sequencing of nuclear and chloroplast DNA regions of Syntrichia sarconeurum, long considered to be Antarctic endemic moss species, are summarised. Molecular analyses confirmed the conspecificity of Syntrichia sarconeurum with S. lithophila and S. pygmaea. This taxonomic conclusion implies that the correct name for the species in the genus Syntrichia is S. lithophila and S. sarconeurum is a new synonym of this name. It is because S. sarconeurum takes priority from 2007, whereas S. lithophila is based on Tortula lithophila which was validly published in 1906 and it is the next earliest legitimate name at the rank of species to be used. Syntrichia sarconeurum, as traditionally conceived, proved to be a heterogeneous taxon actually consisting of two distinct species, namely S. lithophila and S. frigorideserticola nom. nov., which is a new name for Sarconeurum antarcticum whose epithet is not available in Syntrichia. Australian and New Zealand plants of Syntrichia with propaguloid leaf apices are definitely distinct from South American and Antarctic S. lithophila and S. frigorideserticola and the correct name for them is S. abruptinervis comb. nov., based on Tortula abruptinervis.

Taxonomic notes on the New Zealand flora: lectotypification of fern and lycophyte type specimens previously identified as holotypes

ABSTRACT The electronic Flora of New Zealand – Ferns and Lycophytes includes 466 basionyms relevant to the New Zealand flora. These names are typified by 281 lectotypes, 4 neotypes, 1 conserved type, 4 names for which a designation has not been made, and 25 for which a type could not be located. The remaining 151 basionyms have been considered in initial editions of the Flora as having holotypes. However, 37 of these require lectotypification in order to comply with the International Code of Nomenclature for algae, fungi, and plants, as well as suggestions for “best practice”. This is either because the full extent of original material was not considered, or had not been located, or because specimens that had been cited by other authors as holotypes and isotypes are, in reality, often syntypes from which a lectotype must be chosen. 21 of these 37 lectotypes have been inadvertently designated by earlier authors, and a further 16 are designated here for the first time. Lectotypes are being chosen where possible for all names at specific and subspecific rank, for which no holotype was designated by the original author, in order to fix the application of the name concerned. Justification for the choice is provided in each case. This article is a contribution towards clarifying the taxonomic and nomenclatural status of New Zealand plants for the plant names database (Ngā Tipu Aotearoa) and the electronic Flora of New Zealand.

The effect of single biome occupancy on the estimation of biome shifts and the detection of biome conservatism.

Biome conservatism is often regarded as common in diversifying lineages, based on the detection of low biome shift rates or high phylogenetic signal. However, many studies testing biome conservatism utilise a single-biome-per-species approach, which may influence the detection of biome conservatism. Meta-analyses show that biome shift rates are significantly lower (less than a tenth), when single biome occupancy approaches are adopted. Using New Zealand plant lineages, estimated biome shifts were also significantly lower (14–67% fewer biome shifts) when analysed under the assumption of a single biome per species. Although a single biome approach consistently resulted in lower biome shifts, it detected fewer instances of biome conservatism. A third of clades (3 out of 9) changed status in biome conservatism tests between single and multiple biome occupancy approaches, with more instances of significant biome conservatism when using a multiple biome occupancy approach. A single biome approach may change the likelihood of finding biome conservatism because it assumes biome specialisation within species, falsely recognises some biome shift types and fails to include other biome shift types. Our results indicate that the degree of biome fidelity assumed has a strong influence on analyses assessing biome shift rates, and biome conservatism testing. We advocate analyses that allow species to occupy multiple biomes.

Coprosma autumnalis (kanono; Rubiaceae) in New Zealand: nomenclature, iconography and phenology

The correct name for the New Zealand plant, kanono (Rubiaceae), is Coprosma autumnalis Colenso, which name is lectotypified here. A drawing made of the species by John Buchanan in the late 1860s is reproduced. The phenology of the plant, marked in the specific epithet, is examined.

Taxonomic notes on the New Zealand flora: lectotypes in Polypodiaceae and Blechnaceae

ABSTRACT Notogrammitis (Polypodiaceae) is a medium-sized genus of ferns in New Zealand with 11 indigenous species. Lectotypes are chosen here for the basionyms Asplenium angustifolium Jacq., Grammitis humilis Hombr. and G. rigida Hombr., but no type material has been found for Grammitis australis var. alpina S.Jones or G. australis var. villosa Hook.f., and the types for these names remain undesignated. In Blechnum, a lectotype is designated for Lomaria colensoi Hook.f. and a second-step lectotypification made for Stegania fluviatilis R.Br. Lectotypes are being chosen where possible for all names at specific and subspecific rank, for which no holotype was designated by the original author, in order to fix the application of the name concerned. Justification for the choice is provided in each case. This article is a contribution towards clarifying the taxonomic and nomenclatural status of New Zealand plants for the plant names database (Ngā Tipu Aotearoa) and the electronic Flora of New Zealand.

Flower size variation in Danhatchia (Orchidaceae)

Danhatchia novaehollandiae and D. australis were separated at species rank due to differences in petal length and flower opening, with the Australian species having smaller tardily opening flowers. From this, flower lengths for Australia and New Zealand are expected to be bi-modally distributed with peaks at c. 3 mm and c. 5 mm respectively. Quantification of flower size found flower length was unimodal, with nearly identical ranges in Australian and New Zealand plants. Flower size variation in Australian and New Zealand Danhatchia specimens has two significant contributing components, inter-individual variation, and ontogenetic variation where flowers increase in size as they age. Dimensions quoted by Edgar and Moore (1970) and Jones and Clements (2018) reflect upper and lower limits on the range of variation in flower size present in both New Zealand and Australia, respectively. Within herbarium material, 20% of flowers on New Zealand specimens, and 40% of flowers on Australian specimens exhibited signs of opening. There was no correlation between flower size and opening, as might be expected if the two species were both present in Australia and/or New Zealand. Neither the biogeographic context, pollination ecology, nor morphological evidence support Danhatchia australis and D. novaehollandiae as distinct species.

Taxonomic notes on the New Zealand flora: lectotypes in Pteridaceae

ABSTRACT Pteridaceae is a large family of ferns in New Zealand with six genera, 15 indigenous species and 11 naturalised species. Eleven lectotypes are designated for basionyms relevant to New Zealand – Adiantum affine var. heterophyllum Colenso, A. cunninghamii Hook., A. pullum Colenso, A. trapeziforme G.Forst., A. trigonum Labill., Cheilanthes sieberi var. deltoidea J.B.Armstr., C. kirkii J.B.Armstr., Pteris affinis A.Rich., P. macilenta A.Rich., P. macilenta var. saxatilis Carse, and P. pendula Colenso. No type material has been found for the indigenous taxon Adiantum affine var. chathamicum Field, and the type for this name remains undesignated. Lectotypes are being chosen where possible for all names at specific and subspecific rank, for which no holotype was designated by the original author, in order to fix the application of the name concerned. Justification for the choice is provided in each case. This article is a contribution towards clarifying the taxonomic and nomenclatural status of New Zealand plants for the plant names database (Ngā Tipu Aotearoa) and the electronic Flora of New Zealand.

A review of the fern genus Pellaea (Pteridaceae) in Australasia

Five indigenous species of Pellaea in Australasia belong to section Platyloma. Their taxonomic history is outlined, morphological, cytological and genetic evidence for their recognition reviewed, and new morphological and chloroplast DNA-sequence data provided. Australian plants of P. falcata (R.Br.) Fée are diploid and have longer, narrower pinnae than do New Zealand plants previously referred to P. falcata, which are tetraploid. Evidence indicates that P. falcata does not occur in New Zealand, and that collections so-named are P. rotundifolia (G.Forst.) Hook. Chloroplast DNA sequences are uninformative in distinguishing Australian P. falcata from New Zealand P. rotundifolia, but show that Australian P. nana is distinct from both. Sequence data also show that Australian and New Zealand populations of P. calidirupium Brownsey & Lovis are closely related, and that Australian P. paradoxa (R.Br.) Hook. is distinct from other Australian species. Although P. falcata is diploid and P. rotundifolia tetraploid, P. calidirupium, P. nana (Hook.) Bostock and P. paradoxa each contain multiple ploidy levels. Diploid populations of Pellaea species are confined to Australia, and only tetraploids are known in New Zealand. Evolution of the group probably involved hybridisation, autoploidy, alloploidy, and possibly apomixis. Further investigation is required to resolve the status of populations from Mount Maroon, Queensland and the Kermadec Islands.

Shoot flammability is decoupled from leaf flammability, but controlled by leaf functional traits

Abstract Flammability is an important plant trait, relevant to plant function, wildfire behaviour and plant evolution. However, systematic comparison of plant flammability across ecosystems has proved difficult because of varying methodologies and assessment of different fuels comprising different plant parts. We compared the flammability of plant species at the leaf‐level (most commonly used in flammability studies) and shoot‐level (which retains aspects of plant architecture). Furthermore, we examined relationships between leaf functional traits and flammability to identify key leaf traits determining shoot‐level flammability. We collated and analysed existing leaf‐ and shoot‐level flammability data from 43 common indigenous perennial New Zealand plant species, along with existing data on leaf morphological and chemical traits. Shoot‐level flammability was decoupled from leaf‐level flammability. Moreover, leaf‐level rankings of flammability were not correlated with rankings of flammability of plants derived from expert opinion based on field observations, while shoot‐level rankings had a significant positive relationship. Shoot‐level flammability was positively correlated with leaf dry matter content (LDMC), phenolics and lignin, and negatively correlated with leaf thickness. Synthesis. Our study suggests that shoot‐level measurements of flammability are a useful and easily replicable way of characterizing the flammability of plants, particularly canopy flammability. With many parts of the world becoming more fire‐prone, due to anthropogenic activities, such as land‐use change and global warming, this finding will help forest and fire managers to make informed decisions about fuel management, and improve modelling of fire‐vegetation‐climate feedbacks under global climate change. Additionally, we identified some key, widely measured leaf traits, such as leaf dry matter content (LDMC), that may be useful surrogates for plant flammability in global dynamic vegetation models.

Taxonomic notes on the New Zealand flora: lectotypes and a new combination in Blechnaceae

ABSTRACTBlechnaceae is a medium-sized family of ferns in New Zealand with one genus, 23 indigenous species, two naturalised species and two nothospecies. A new combination, Blechnum × digenum (Parris) Brownsey & Perrie, is made for the hybrid between Blechnum molle (Parris) Christenh. and B. parrisiae Christenh. 11 lectotypes are chosen for basionyms relevant to New Zealand – Lomaria dura T. Moore, L. filiformis A. Cunn., L. membranacea Colenso ex Hook., L. nigra Colenso, L. oligoneuron Colenso, L. parvifolia Colenso, L. paucijuga Colenso, L. pumila Raoul, L. rotundifolia Colenso, Parablechnum procerum var. acuminatum C. Presl, and Stegania procera var. stipulosa A. Rich. No type material has been found for Blechnum capense var. auriculatum Domin, B. capense var. contractum Domin, B. capense var. hookerianum Domin, Lomaria paleacea Potts, or Lomaria pygmaea Colenso, and the types for these names remain undesignated. Lectotypes are being chosen where possible for all names at specific and subspecific rank, for which no holotype was designated by the original author, in order to fix the application of the name concerned. Justification for the choice is provided in each case. This article is a contribution towards clarifying the taxonomic and nomenclatural status of New Zealand plants for the plant names database (Ngā Tipu Aotearoa) and the electronic Flora of New Zealand.

Taxonomic notes on the New Zealand flora: lectotypes in Dryopteridaceae and Nephrolepidaceae

ABSTRACTDryopteridaceae is a large family of ferns with 13 indigenous species in New Zealand, and Nephrolepidaceae a small family with two indigenous species. Five lectotypes are chosen for basionyms relevant to New Zealand – Aspidium cystostegium Hook., Nephrodium decompositum var. pubescens Hook., N. pentangulare Colenso, Polypodium setosum G.Forst., and Polypodium silvaticum Colenso. A neotype is designated for Nephrodium brownii Desv. No type material has been found for Aspidium coriaceum var. acutidentatum A.Rich., and the type for this remains undesignated. Lectotypes or neotypes need to be chosen for all names at specific and infraspecific rank, for which no holotype was designated by the original author, in order to fix the application of the name concerned. Justification for the choice is provided in each case. This article is a contribution towards clarifying the taxonomic and nomenclatural status of New Zealand plants for the plant names database (Ngā Tipu Aotearoa) and the electronic Flora of New Zealand.

Taxonomic notes on the New Zealand flora: lectotypes in Isoetaceae and Lycopodiaceae

ABSTRACTWithin the Lycopodiopsida, Lycopodiaceae is a medium-sized family of lycophytes in New Zealand with five genera and 11 indigenous species, and Isoetaceae is a small family with one genus and two species. Fourteen lectotypes are chosen for basionyms relevant to New Zealand – Isoetes alpina Kirk, Lycopodium australianum Herter, L. billardierei Spring, L. consimile Colenso, L. curvifolium Colenso, L. distans Colenso, L. drummondii Spring, L. lessonianum A.Rich., L. novozealandicum Colenso, L. sanguisorba Spring, L. serpentinum Kunze, L. varium var. gracile Kirk, L. varium var. polaris Kirk, and Phylloglossum drummondii Kunze. No type material has been found for Lycopodium decurrens Colenso, and the type for this remains undesignated. Lectotypes need to be chosen for all names at specific and subspecific rank, for which no holotype was designated by the original author, in order to fix the application of the name concerned. Justification for the choice is provided in each case. This article is a contribution towards clarifying the taxonomic and nomenclatural status of New Zealand plants for the plant names database (Ngā Tipu Aotearoa) and the electronic Flora of New Zealand.

Chloroplast diversity of giant buttercup (Ranunculus acris L., Ranunculaceae) in New Zealand and in its native range

ABSTRACTThe species Ranunculus acris L. (giant buttercup) is native to Europe but has a very large naturalised range in several countries. In New Zealand it is a serious weed of pasture, particularly in high rainfall areas. Biological control options are being sought as chemical control has proven insufficient and is leading to resistance. To find efficient pathogens or natural enemies the search needs to focus on areas of origin of the material present in New Zealand. The target range of biocontrol agents needs to be broad enough to include all R. acris haplotypes found in New Zealand but also host specific enough to not attack unintended targets. A previous study found that R. acris in New Zealand has very high chloroplast diversity, with mixed chloroplast haplotypes occurring in single populations. Haplotype-specific genetic data are therefore essential for the identification of the origin and for sourcing effective biocontrol agents. The aim of this study was to identify putative origins of the material found in New Zealand. We compared chloroplast diversity in New Zealand populations of R. acris to parts of the native and naturalised ranges, including areas of the putative origin of the New Zealand plants. The non-coding chloroplast regions trnK and psbJ-petA were sequenced to identify haplotypes. We found that the native range also had high chloroplast diversity, and that most New Zealand chloroplast haplotypes were common in northern Europe and the United Kingdom. Further sampling would be required to trace the remaining two New Zealand haplotypes to their origin, however the results suggest that R. acris was introduced from several regions in Europe.

Dan Watkins Scholarship in Weed Science

Dan Watkins was one of the founders of the Ivon Watkins Ltd herbicide company, based in New Plymouth, which later became Ivon Watkins Dow and is now Dow AgroSciences. He was a leading figure in the early weed science research arena within New Zealand. Dan Watkins was a founder of the New Zealand Weeds conference, forerunner of the New Zealand Plant Protection Society. He was also a member of the New Zealand National Research Council and was involved with other scientific bodies. This scholarship has been set up and financed by Dr
 George Mason, one of the founders of Taranaki Nuchem (now Zelam Limited), in memory of Dan Watkins and to recognise his contribution to weed science within New Zealand.
 David Kerr, recipient of the 2017/18 Dan Watkins Scholarship in Weed Science, is an MSc student at Canterbury University. His thesis is on the reproduction and ecology of Mimulus guttatus DC, a persistent riparian weed imported from the western United States into New Zealand as an ornamental plant. This weed grows vigorously from the smallest fragments and has potential to cause major damage to river systems; crowding out natives and increasing flooding potential. David’s research aims to investigate how reproductive strategy facilitates the spread of M. guttatus, particularly the role of seed banks in establishing populations after habitat disturbance.
 Mimulus guttatus produces abundant seeds of very small size (approx. 500 µm in diameter), which have been demonstrated to be viable after travelling hundreds of metres downstream or dispersing in large numbers by wind from dry seed pods. Traditional management techniques involve mechanical clearance or use of herbicides in affected rivers adjoining pasture land. These approaches have notable negative consequences, including waterway contamination and facilitation of fragment dispersal and growth.
 The first part of David’s thesis involved a survey of 250 contiguous 50-m long stretches of river at six valley locations around Banks Peninsula; recording the presence of M. guttatus and abundance as well as site data such as shading and evidence of grazing on M. guttatus plants. The data from this survey indicated a trend towards greater abundance in more open areas and occasional patches in more shaded regions where the canopy allows sufficient light to grow. Previous work has identified a lack of understanding of transient overwintering seed banks.
 The second part of David’s thesis will investigate the hypothesis that persistent seed banks allow M. guttatus to establish upstream of populations in shaded areas when the canopy is disturbed. Mimulus guttatus in its native range has high fitness costs associated with selfing. The third will investigate the reproductive strategy of M. guttatus with reference to rates of selfing, and seed viability to test the hypothesis that historic pollinator and mate limitation have driven a change towards selfing.
 This work will further the understanding of the reproductive strategy of M. guttatus and how it invades river systems and inform land-management and conservation decisions. This has particular relevance to the role of sustainable ecosystem-level approaches to weed management such as native shade belts and conservation of existing forest around waterways to prevent weed establishment.