Molecular evidence for bicontinental hybridogenous genomic constitution in Lepidium sensu stricto (Brassicaceae) species from Australia and New Zealand

Lepidium sensu stricto (s.s.) (Brassicaceae) (ca. 150 species) is distributed worldwide with endemic species on every continent. It is represented in Australia and New Zealand by 19 and seven native species, respectively. In the present study we used a nuclear ribosomal internal transcribed spacer (ITS) phylogeny in comparison with a cpDNA phylogeny to unravel the origin of Australian/New Zealand species. Although phylogenetic relationships within Lepidium s.s. were not fully resolved, the cpDNA data were in agreement with a Californian origin of Lepidium species from Australia/New Zealand. Strongly conflicting signals between the cp- and nuclear DNA phylogenetic analysis clearly indicated hybridogenous genomic constitution of Australian Lepidium s.s. species: All 18 studied Australian/New Zealand Lepidium s.s. species examined shared a Californian cpDNA type. While eleven Australian/New Zealand species appeared to harbor a Californian ITS type, a group of seven species shared a South African ITS type. This pattern is most likely explained by two trans-oceanic dispersals of Lepidium from California and Africa to Australia/New Zealand and subsequent hybridization followed by homogenization of the ribosomal DNA either to the Californian or South African ITS type in the two different lineages. Calibration of our molecular trees indicates a Pliocene/Pleistocene origin of Lepidium in Australia/New Zealand. Low levels of cpDNA and ITS sequence divergence and unresolved topologies within Australian/New Zealand species suggest a rapid and recent radiation of Lepidium after the hybridization event. This coincides with dramatic climatic changes in that geological epoch shaping the composition of the vegetation.     

Potential risk of accidental introduction of Asian gypsy moth (Lymantria dispar) to Australasia: effects of climatic conditions and suitability of native plants

1 The potential risk of the establishment of the Asian strain of the gypsy moth (AGM) (Lymantria dispar) in New Zealand and Australia (Australasia) was assessed from a study of the insect's host range and potential distribution. In New Zealand, viable eggs of AGM have been continuously intercepted on cargo from Asia, and therefore there is a high probability of accidental introductions of AGM to Australasia. 2 We predicted potential distribution ranges of AGM based on climatic conditions. Asian gypsy moth is predicted to be able to persist in N and SE New Zealand and SE and SW Australia. 3 Using three populations of AGM and 59 species (seven families) of plant (55 from Australasia and four from elsewhere), we also conducted laboratory trials to examine the ability of AGM larvae to complete development on native plants from Australasia. Asian gypsy moth was able to complete development on 26 out of the 55 native species tested. Furthermore, larval performance on at least five species of Australian native plant was as good as on AGM's preferred host species (Quercus pubescens and Q. robur). 4 Larval performance of AGM was poor on all but one species of New Zealand native tree species (Nothofagus solandri), and therefore the risk of establishment in the indigenous forests of New Zealand is considered to be low. 5 Given the suitability of some Australian plants and the climatic suitability for the establishment of AGM, this insect should be treated as a serious quarantine threat and managed accordingly, particularly in Australia.     

Protura in native and exotic forests in the North Island of New Zealand

Abstract

This study provides data on population and community ecology of Protura in native forests and Pinus radiata plantations in New Zealand. Abundance, age structure, sex ratios, biodiversity, and relationship with soil chemistry are discussed. Protura were significantly more abundant in pine plantations in comparison to native forests. Among native forests, Protura were most abundant under Southern beech (Nothofagus solandri). The abundance patterns may reflect the association between Protura and fungal communities in the soil. No correlation was found between soil organic matter, nitrogen, phosphorous, pH, cation exchange capacity, and the density of Protura. Protura assemblage composition was significantly related to forest type. New Zealand endemic species were associated with native forests; species with distribution outside New Zealand dominated in pine plantations. The distribution records within New Zealand were expanded for five species. The Protura fauna of New Zealand was increased to 18 species. Berberentulus capensis, Eosentomon australicum and Australentulus tillyardi are new records for New Zealand fauna.     

Gender diversity of editorial boards and gender differences in the peer review process at six journals of ecology and evolution

Despite substantial progress for women in science, women remain underrepresented in many aspects of the scholarly publication process. We examined how the gender diversity of editors and reviewers changed over time for six journals in ecology and evolution (2003–2015 for four journals, 2007–2015 or 2009–2015 for the other two), and how several aspects of the peer review process differed between female and male editors and reviewers. We found that for five of the six journals, women were either absent or very poorly represented as handling editors at the beginning of our dataset. The representation of women increased gradually and consistently, with women making up 29% of the handling editors (averaged across journals) in 2015, similar to the representation of women as last authors on ecology papers (23% in 2015) but lower than the proportion of women among all authors (31%) and among members of the societies that own the journals (37%–40%). The proportion of women among reviewers has also gradually but consistently increased over time, reaching 27% by 2015. Female editors invited more female reviewers than did male editors, and this difference increased with age of the editor. Men and women who were invited to review did not differ in whether they responded to the review invitation, but, of those that responded, women were slightly more likely to agree to review. In contrast, women were less likely than men to accept invitations to serve on journal editorial boards. Our analyses indicate that there has been progress in the representation of women as reviewers and editors in ecology and evolutionary biology, but women are still underrepresented among the gatekeepers of scholarly publishing relative to their representation among researchers.     

The forgotten 60%: bird ecology and management in New Zealand?s agricultural landscape

Production lands make up 58% of Aotearoa?New Zealand?s landcover and contribute greatly not only to the national economy but also to patterns and trends in native and introduced avian biodiversity. However, unlike in native forest and other indigenous habitats, birds in agro-ecosystems have received little attention to date. We argue that this is due to (1) a research focus on understanding the causes of the dramatic decline of New Zealand?s critically endangered, endemic species, (2) an adherence to a ?preservation for intrinsic value? over a ?conservation through sustainable use? paradigm for environmental management, and (3) a historical view of production landscapes as being devoid of endemic and native species and thus of no conservation value. In countering these attitudes, we suggest that the agricultural matrix may contain more native species than many people believe, and that many introduced bird species are key contributors to the social and environmental performance and resilience of these systems. We draw attention to the context, composition, ecology, and status of native and introduced birds in production landscapes in New Zealand, particularly in the face of ongoing agricultural intensification. We first identify the potential roles of local habitat, landscape composition, and introduced predators in shaping farmland bird communities. We then highlight the potential threats and opportunities for birds posed by ongoing intensification, particularly the influences of habitat modification and simplification, increased ecological subsidies through farm inputs, increased stocking rates and yields, and altered predator?prey interactions. We suggest the landscape is the appropriate spatial scale for research and management, and call for an integrated approach to the investigation of farmland birds that combines ecology, sociology, and agro-ecosystems management, and includes farmers, researchers, regulators, and the wider New Zealand public.     

The role of replication studies in ecology

Recent large‐scale projects in other disciplines have shown that results often fail to replicate when studies are repeated. The conditions contributing to this problem are also present in ecology, but there have not been any equivalent replication projects. Here, we survey ecologists' understanding of and opinions about replication studies. The majority of ecologists in our sample considered replication studies to be important (97%), not prevalent enough (91%), worth funding even given limited resources (61%), and suitable for publication in all journals (62%). However, there is a disconnect between this enthusiasm and the prevalence of direct replication studies in the literature which is much lower (0.023%: Kelly 2019) than our participants' median estimate of 10%. This may be explained by the obstacles our participants identified including the difficulty of conducting replication studies and of funding and publishing them. We conclude by offering suggestions for how replications could be better integrated into ecological research.     

Parasitism of the lucerne pest Sitona discoideus Gyllenhal (Coleoptera: Curculionidae) and non-target weevils by Microctonus aethiopoides Loan (Hymenoptera: Braconidae) in south-eastern Australia, with an assessment of the taxonomic affinities of non-target hosts of M. aethiopoides recorded from Australia and New Zealand

Abstract  The braconid parasitoid Microctonus aethiopoides Loan has been released in Australia and New Zealand for biological control of the lucerne pest Sitona discoideus Gyllenhal. In New Zealand, the parasitoid attacks a number of endemic weevil species. A survey of Curculionoidea found in and near lucerne in south-eastern Australia was carried out to investigate whether similar non-target parasitism was occurring, and to relate this to levels of parasitism found in the target host, S. discoideus . Some of the original M. aethiopoides release sites were particularly targeted in the survey of 25 sites in Victoria, New South Wales and South Australia. Almost 2500 weevils were collected, of which over 90% were S. discoideus , with the remaining 197 other weevils comprising 29 species found at 15 of the 25 sites. Parasitism of S. discoideus by M. aethiopoides occurred at 12 lucerne sites, with levels ranging from 0 to 25%. A single incidence of parasitism of a species of an Australian native weevil Prosayleus sp. by M. aethiopoides was recorded. No parasitism of any other weevil species was observed. The taxonomic affinities between Sitona and native Australian and New Zealand weevils are discussed, concluding that non-target host range in M. aethiopoides may be determined more by ecological factors than by taxonomic affinities among its hosts.     

Frugivore gape size and the evolution of fruit size and shape in southern hemisphere floras

Abstract The present study uses differences among frugivore faunas of the southern hemisphere landmasses to test whether frugivore characteristics have influenced the evolution of fruit traits. Strong floristic similarities exist among southern landmasses; for example, 75% of New Zealand vascular plant genera also have species in Australia. However, plants in Australia and South America have evolved in the presence of a range of mammalian frugivores, whereas those in New Zealand, New Caledonia and the Pacific Islands have not. In addition, the avian frugivores in New Zealand and New Caledonia are generally smaller than those of Australia. If frugivore characteristics have influenced the evolution of fruit traits, predictable differences should exist between southern hemisphere fruits, particularly fruit size and shape. Fruit dimensions were measured for 77 New Zealand species and 31 Australian species in trans‐Tasman genera. New Zealand fruits became significantly more ellipsoid in shape with increasing size. This is consistent with frugivore gape size imposing a selective pressure on fruit ingestability. This result is not a product of phylogenetic correlates, as fruit length and width scaled isometrically for Australian species in genera shared with New Zealand. Within‐genus contrasts between New Zealand and Australian species in 20 trans‐Tasman genera showed that New Zealand species have significantly smaller fruits than their Australian counterparts. Within‐genus contrasts between New Zealand and South American species in nine genera gave the same result; New Zealand species had significantly smaller fruits than their South American counterparts. No difference was found in fruit size or shape between New Zealand and New Caledonia congeneric species from 12 genera. These results are consistent with the broad characteristics of the frugivore assemblage influencing the evolution of fruit size and shape in related species. The smaller‐sized New Zealand frugivore assemblage has apparently influenced the evolution of fruit size of colonizing taxa sometimes within a relatively short evolutionary timeframe.     

The importance of viticultural landscape features and ecosystem service enhancement for native butterflies in New Zealand vineyards

The fragmentation of habitats in intensively managed farming landscapes is often considered to be partly responsible for butterfly population decline in Europe and the USA. Although relatively little is known about New Zealand butterfly ecology, agricultural landscapes in lowland New Zealand are managed similarly to those in Europe and ecosystem services (ES) in these landscapes are generally at a low level. In the northern hemisphere, attempts are being made to address the problem through agri-environment schemes, but such farmer compensation is not available in New Zealand. Instead, landowner- and research-led initiatives are currently the only potential approaches. One such project in the Canterbury province, New Zealand, is the Greening Waipara project. This aims to return native plants to viticultural landscapes and enhance ES, and while research has sought to quantify economic benefits of the project, there has been no work to establish if the plantings are improving or are likely to improve non-target invertebrate biodiversity, for example arthropods that are not biocontrol agents. In the first study of its kind in New Zealand, butterfly surveys were conducted in vineyards and linear mixed modelling techniques were used to identify the most important vegetation and structural features which may influence butterfly distribution. While the native planting areas were not important for butterflies, remnant patches of native vegetation in unproductive areas were vital for sedentary species. These results are discussed in relation to the conservation of native species in New Zealand vineyards and in the context of conservation in and around farmland in general.     

Mutualism vs. antagonism in introduced and native ranges: Can seed dispersal and predation determine Acacia invasion success?

Plant species introduced to new regions can escape their natural enemies but may also lose important mutualists. While mutualistic interactions are often considered too diffuse to limit plant invasion, few studies have quantified the strength of interactions in both the native and introduced ranges, and assessed whether any differences are linked to invasion outcomes. For three Acacia species adapted for ant dispersal (myrmecochory), we quantified seed removal probabilities associated with dispersal and predation in both the native (Australian) and introduced (New Zealand) ranges, predicting lower removal attributable to dispersal in New Zealand due to a relatively depauperate ant fauna. We used the role of the elaiosome to infer myrmecochory, and included treatments to measure vertebrate seed removal, since this may become an important determinant of seed fate in the face of reduced dispersal. We then tested whether differences in seed removal patterns could explain differences in the invasion success of the three Acacia species in New Zealand.Overall seed removal by invertebrates was lower in New Zealand relative to Australia, but the difference in removal between seeds with an elaiosome compared to those without was similar in both countries. This implies that the probability of a removed seed being dispersed by invertebrates was comparable in New Zealand to Australia. The probability of seed removal by vertebrates was similar and low in both countries. Differences in the invasive success of the three Acacia species in New Zealand were not explained by differences in levels of seed predation or the strength of myrmecochorous interactions. These findings suggest that interactions with ground foraging seed predators and dispersers are unlikely to limit the ability of Acacia species to spread in New Zealand, and could not explain their variable invasion success.     

Key to the New Zealand species of Psyllaephagus Ashmead (Hymenoptera: Encyrtidae) with descriptions of three new species and a new record of the psyllid hyperparasitoid Coccidoctonus psyllae Riek (Hymenoptera: Encyrtidae)

Abstract  This paper records seven species of wasps in the genus Psyllaephagus (Hymenoptera: Encyrtidae) from New Zealand. All of these species are primary parasitoids of psylloids (Hemiptera: Psylloidea). Two are species previously described from New Zealand: P. acaciae Noyes and P. pilosus Noyes. Two are described Australian species which have established recently: P. bliteus Riek and P. gemitus Riek. Three new species are described here, from New Zealand: P. breviramus sp. nov., P. cornwallensis sp. nov. and P. richardhenryi sp. nov. All species are probably Australian in origin. A key to all seven Psyllaephagus species known from New Zealand is provided. An earlier first record of the Australian psyllid hyperparasitoid Coccidoctonus psyllae Riek (Hymenoptera: Encyrtidae), previously first recorded from New Zealand in 2006, is noted.     

The role of blackbirds (

The naturalised European blackbird (Turdus merula) is the most widely distributed avian seed disperser in New Zealand. Together with the native silvereye (Zosterops lateralis) they are the major seed dispersers over large areas of New Zealand. I review the international literature on aspects of the ecology and behaviour of blackbirds relevant to their potential for dispersing weeds in New Zealand. Blackbirds eat a wide range of native and exotic fruit including many naturalised species. Their habitat preferences and behaviour result in germinable seeds being deposited in a range of sites, particularly in shrubby habitats, where seedling establishment is likely. Most seeds will be deposited within 50 m but some may be carried a kilometre or more to develop new invasive loci. Blackbirds therefore probably make a major contribution to the development of novel plant communities of naturalised woody weeds. These communities provide fruit more suited to non- endemic native birds and naturalised birds, than to endemic birds. The relative contribution of blackbirds and silvereyes to seed dispersal of native and exotic species requires investigation. The outcome may suggest potential for managing blackbirds as a vector of weed invasions.     

The lack of genetic bottleneck in invasive Tansy ragwort populations suggests multiple source populations.

Jacobaea vulgaris (Asteraceae) is a species of Eurasian origin that has become a serious non-indigenous weed in Australia, New Zealand, and North America. We used neutral molecular markers to (1) test for genetic bottlenecks in invasive populations and (2) to investigate the invasion pathways. It is for the first time that molecular markers were used to unravel the process of introduction in this species.The genetic variation of 15 native populations from Europe and 16 invasive populations from Australia, New Zealand and North America were compared using the amplified fragment length polymorphisms (AFLP's). An analysis of molecular variance showed that a significant part (10%) of the total genetic variations between all individuals could be explained by native or invasive origin.Significant among-population differentiation was detected only in the native range, whereas populations from the invasive areas did not significantly differ from each other; nor did the Australian, New Zealand and North American regions differ within the invasive range. The result that native populations differed significantly from each other and that the amount of genetic variation, measured as the number of polymorphic bands, did not differ between the native and invasive area, strongly suggests that introductions from multiple source populations have occurred. The lack of differentiation between invasive regions suggests that either introductions may have occurred from the same native sources in all invasive regions or subsequent introductions took place from one into another invasive region and the same mix of genotypes was subsequently introduced into all invasive regions.An assignment test showed that European populations from Ireland, the Netherlands and the United Kingdom most resembled the invasive populations.     

Should the flower bud weevil Anthonomus santacruzi (Coleoptera: Curculionidae) be considered for release against the invasive tree Solanum mauritianum (Solanaceae) in New Zealand?

The invasive tree Solanum mauritianum Scop. has been targeted for biological control in South Africa and New Zealand, by deploying insect agents that could constrain its excessive reproductive output. The flower-feeding weevil Anthonomus santacruzi (Curculionidae) was approved for release in South Africa in 2007 but following the loss of the original culture in quarantine, new stocks were introduced from Argentina in 2008–2009. This study was initiated to confirm that the host range of the new culture was the same as that of the previous one, but also to assess the risks associated with the weevil's release in New Zealand. Different testing procedures, including no-choice tests and multi-choice tests in different arenas, produced inconsistent and ambiguous results. During no-choice tests, oviposition and larval development to adulthood occurred on three non-target species including two native South African and one native New Zealand Solanum species. However, subsequent multi-choice tests and a risk assessment suggested that the risks of anything more than collateral damage to non-target Solanum species are low. Overall, these data do not deviate substantially from the results of the original quarantine tests which facilitated the release of A. santacruzi in South Africa in 2009. Although we argue that none of the New Zealand native and cultivated species are at risk, stronger evidence from open-field trials and chemical ecology studies may be required to convince the regulatory authorities that A. santacruzi is suitable for release in New Zealand.     

New Zealand geckos (Diplodactylidae): Cryptic diversity in a post-Gondwanan lineage with trans-Tasman affinities

We used a multi-gene approach to assess the phylogenetic relationships of New Zealand diplodactylid geckos to their Australian and New Caledonian relatives and to one another. Data from nuclear (RAG-1, PDC) and mitochondrial (ND2, 16S) genes from >180 specimens representing all 19 recognized New Zealand taxa and all but two of 20 putatively new species suggested by previous studies were analyzed using Maximum Parsimony, Maximum Likelihood and Bayesian inference. All analyses retrieved a monophyletic New Zealand clade, most closely related to the Australian Diplodactylidae exclusive of Pseudothecadactylus. Hoplodactylus is paraphyletic and composed of two morphological groups: a broad-toed clade, consisting of the island-restricted, largest extant species, Hoplodactylus duvaucelii, and the species-rich, wide-ranging Hoplodactylus maculatus clade; and a narrow-toed clade, comprising five monophyletic subgroups: Naultinus, the Hoplodactylus pacificus and Hoplodactylus granulatus clades, and the distinctive species Hoplodactylus rakiurae and Hoplodactylus stephensi. Each of these lineages is here recognized at the generic level. Our data support recognition of 16 new species (36 total), and five new or resurrected genera (seven total). The New Zealand diplodactylid radiation split from its Australian relatives 40.2mya (95% highest posterior density estimate 28.9-53.5), after the opening of the Tasman Sea. Their distribution cannot, therefore, be regarded as derived as a result of Gondwanana vicariance. The age of the New Zealand crown group, 24.4mya (95% highest posterior density estimate 15.5-33.8), encompasses the period of the 'Oligocene drowning' of New Zealand and is consistent with the hypothesis that New Zealand was not completely inundated during this period. Major lineages within New Zealand geckos diverged chiefly during the mid- to late Miocene, probably in association with a suite of geological and climatological factors that have characterized the region's complex history.     

Native vegetation structure,landscape features and climate shape non-native plant richness and cover in New Zealand native shrublands

Aim

Studies investigating the determinants of plant invasions rarely examine multiple factors and often only focus on the role played by native plant species richness. By contrast, we explored how vegetation structure, landscape features and climate shape non-native plant invasions across New Zealand in mānuka and kānuka shrublands.

Location

New Zealand.

Method

We based our analysis on 247 permanent 20 × 20-m plots distributed across New Zealand surveyed between 2009 and 2014. We calculated native plant species richness and cumulative cover at ground, understorey and canopy tiers. We examined non-native species richness and mean species ground cover in relation to vegetation structure (native richness and cumulative cover), landscape features (proportion of adjacent anthropogenic land cover, distance to nearest road or river) and climate. We used generalized additive models (GAM) to assess which variables had greatest importance in determining non-native richness and mean ground cover and whether these variables had a similar effect on native species in the ground tier.

Results

A positive relationship between native and non-native plant species richness was not due to their similar responses to the variables examined in this study. Higher native canopy richness resulted in lower non-native richness and mean ground cover, whereas higher native ground richness was associated with higher native canopy richness. Non-native richness and mean ground cover increased with the proportion of adjacent anthropogenic land cover, whereas for native richness and mean ground cover, this relationship was negative. Non-native richness increased in drier areas, while native richness was more influenced by temperature.

Main Conclusions

Adjacent anthropogenic land cover seems to not only facilitate non-native species arrival by being a source of propagules but also aids their establishment as a result of fragmentation. Our results highlight the importance of examining both cover and richness in different vegetation tiers to better understand non-native plant invasions.     

The diversity and origin of exotic ants arriving in New Zealand via human-mediated dispersal

The number of exotic ant species being dispersed to new regions by human transportation and the trade pathways responsible for this are poorly understood. In this study, the taxonomic diversity, trade pathways, and origin of exotic ants intercepted at the New Zealand border were examined for the period 1955–2005. Overall, there were a total 4355 interception records, with 115 species from 52 genera. The 10 most frequently intercepted genera, and the 20 most frequently intercepted species contributed > 90% of all records. Many of the species frequently intercepted are regarded as invasive species, and several are established in New Zealand. The most intercepted species was Pheidole megacephala . Despite a relatively low trade relationship, a high proportion (> 64%) of the exotic ants which were intercepted originated from the Pacific region. However, the majority of species intercepted from the Pacific was exotic to the region (71%), or to a lesser extent, wide-ranging Pacific native species. No endemic species from the Pacific were intercepted. The effectiveness of detecting exotic ant species at the New Zealand border ranged from 48–78% for different trade pathways, indicating a number of species remain undetected. Trade routes associated with specific geographical regions represent a major filter for the arrival of exotic ant species. Despite the importance of the Pacific as a frequent pathway, we suggest that the future establishment of exotic ant species in New Zealand is likely to be mitigated by a renewed focus on trade routes with cool temperate regions, particularly Australia.