Philip Hulme

Lincoln University · Bio-Protection Research Centre

The ability to reproduce via multiple strategies is crucial for the invasion success of alien plant species. Here, we use Carpobrotus taxa (species and hybrids) to explore how trade-offs between and within these strategies may influence plant invasion dynamics. Native to South Africa, Carpobrotus plants are globally prominent in coastal ecosystems,...

Aim Identifying habitats vulnerable to plant invasions is essential for developing efficient management programmes. We assessed trends in richness and cover of non‐native plants in indigenous shrublands and forests across New Zealand. We investigated whether species classed as invasive species exhibited higher levels of plant invasion than naturali...

Early detection and rapid response are essential to deal effectively with new introductions of invasive alien species (IAS). Citizen science platforms for opportunistic recording of species are increasingly popular, and there is potential to harvest their data for early detection of IAS, but this has not been tested. We evaluated the potential of d...

Effective biosecurity policies are essential to address several major sociological and environmental challenges facing humankind including existential pandemic risks, threats to food security, loss of ecosystem services and public resistance to pesticides and vaccines. Yet biosecurity is subject to multiple interpretations that include dealing with...

Anticipating future biosecurity threats to prevent their occurrence is the most cost‐effective strategy to manage invasive alien species. Yet, biological invasions are complex, highly uncertain processes. High uncertainty drives decision‐making away from strategic preventative measures and towards operational outcomes aimed at post‐invasion managem...

International tourists are recognised as vectors of alien microbes, plants, and animals into protected areas worldwide, either by introducing species from overseas or redistributing alien species within a region. Quantitative estimates of the risk from this introduction pathway have relied on surveys of invasive alien species associated with touris...

Understanding the magnitude of biosecurity risks in aquatic environments is increasingly complex and urgent because increasing volumes of international shipping, rising demand for aquaculture products, and growth in the global aquarium trade, are accelerating invasive alien species spread worldwide. These threats are especially pressing amid climat...

Although invasive alien species have long been recognized as a major threat to nature and people, until now there has been no comprehensive global review of the status, trends, drivers, impacts, management and governance challenges of biological invasions. The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES)...

While data on biological invasions and their economic toll are increasingly available, drivers of susceptibility to damage and cost-effectiveness of management in reducing long-term costs remain poorly understood. We used data describing the damage costs of, and management expenditure on, invasive species among 56 nations between 2000 and 2020 repo...

Biological invasions have profound impacts on biodiversity and ecosystem functioning and services, resulting in substantial economic and health costs estimated in the trillions of dollars. Preventing and managing biological invasions are vital for sustainable development, aligning with the goals of the United Nations Biodiversity Conference. Howeve...

On 4 September 2023, the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) released the most comprehensive global synthesis of the current knowledge on the biological invasion process and the impacts of invasive alien species, i.e., the Thematic Assessment Report on Invasive Alien Species and their Control (he...

Invasive alien species (IAS) adversely impact biodiversity, ecosystem functions and socio-economics. Citizen science can be an effective tool for IAS surveillance, management and research, providing large datasets over wide spatial extents and long time periods, with public participants generating knowledge that supports action. We demonstrate how...

It has long been hypothesised that introduced species can evolve to become better competitors, which in turn will enable some of them to become invasive. The evolution of increased competitive ability hypothesis (EICA) gives a possible answer for why some introduced plants become invasive by stating that they can escape natural coevolved enemies (p...

Summary for Policymakers of the Thematic Assessment Report on Invasive Alien Species and their Control of the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services.

Here we present the results of a study investigating the effects of vegetation structure, landscape features and climate on non-native plant invasions across New Zealand in mānuka (Leptospermum scoparium) and kānuka (Kunzea ericoides) shrublands.

Several hundred studies have attempted to estimate the monetary cost arising from the management and/or impacts of invasive alien species. However, the diversity of methods used to estimate the monetary costs of invasive alien species, the types of costs that have been reported, and the spatial scales at which they have been assessed raise importan...

The drivers of susceptibility to damage and management effectiveness in reducing the biological-invasion costs remain poorly understood. We used InvaCost data describing the damage costs of, and management expenditure on, invasive species among 56 nations to test whether higher-income nations have more capacity to limit the damage incurred by invas...

This Chapter provides an analysis and synthesis of how direct and indirect anthropogenic drivers of change in nature, along with natural drivers and biodiversity loss itself, are responsible for the transport, introduction, establishment and spread of invasive alien species. The chapter first outlines the conceptual and analytical framework and app...

The relative contribution of adaptation and phenotypic plasticity can vary between core and edge populations, with implications for invasive success. We investigated the spread of the invasive yellow monkeyflower, Erythranthe gutatta in New Zealand, where it is spreading from lowland agricultural land into high-elevation conservation areas. We inve...

The Andes mountain range in South America has a high level of endemism and is a major source of ecosystem services. The Andes is increasingly threatened by anthropo-genic disturbances that have allowed the establishment of non-native plants, mainly in the lower elevation areas. However, synergies between climate change and anthropogenic pressure ar...

One Biosecurity is an interdisciplinary approach to policy and research that builds on the interconnections between human, animal, plant, and ecosystem health to effectively prevent and mitigate the impacts of invasive alien species. To support this approach requires that key cross-sectoral research innovations be identified and prioritized. Follow...

International seed trading provides a significant introductory pathway for weed seeds, and many globally established weeds originated as contaminants in agricultural seed lots. Management of these trade systems helps minimize agricultural losses and is an important means of preventing future biological incursions. Forage crop seed lots could be con...

Background Biological invasions threaten the functioning of ecosystems, biodiversity, and human well-being by degrading ecosystem services and eliciting massive economic costs. The European Union has historically been a hub for cultural development and global trade, and thus, has extensive opportunities for the introduction and spread of alien spec...

Societal Impact Statement Hybridisation is an important evolutionary force in plants, but it can potentially lead to genetic swamping and extinction of one or both parental species. The threat of extinction is of particular concern if hybridisation occurs between native and introduced species, especially when the native is of national importance. T...

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 Z...

Compared to their native range, non-native plants often experience reduced levels of herbivory in the introduced range. This may result in reduced pressure to produce chemical defences that act against herbivores. We measured the most abundant secondary metabolites found in Rumex spp., namely oxalates, phenols and tannins. To test this hypothesis,...

Background: Biological invasions threaten the functioning of ecosystems, biodiversity, and human well-being by degrading ecosystem services and eliciting massive economic costs. The European Union, as the world’s third-largest economy, has historically been a hub for cultural development and global trade, and thus, has extensive opportunities for t...

Context or problem The continued increase in numbers of herbicide-resistant weed species in field crops constrains sustainable agricultural practices worldwide. Countries differ markedly in numbers of herbicide-resistant weed species in field crops yet the extent this reflects global variation in agricultural intensification is not known. Objectiv...

Plant invasions, a byproduct of globalization, are increasing worldwide. Because of their ecological and economic impacts, considerable efforts have been made to understand and predict the success of non-native plants. Numerous frameworks, hypotheses, and theories have been advanced to conceptualize the interactions of multiple drivers and context...

A common limitation for the effective management of widespread non-native species is translating and implementing the latest scientific knowledge for practitioners. Non-native tree invasions are no exception to this problem. We illustrate how the National Wilding Conifer Control Programme in New Zealand has worked to overcome these limitations thro...

Recreational users of freshwaters (e.g. fishers, boat users etc.) are leading vectors of alien plant spread among lakes. To date no study has integrated information on the associations between awareness, mitigation and residual risk of different lake users, that might provide insights into more effective management of this introduction pathway. Usi...

The enemy release hypothesis states that introduced plants have a competitive advantage due to their release from co-evolved natural enemies (i.e., herbivores and pathogens), which allows them to spread rapidly in new environments. This hypothesis has received mixed support to date, but previous studies have rarely examined the herbivore community,...

Climatic niche shifts occur when species occupy different climates in the introduced range than in their native range. Climatic niche shifts are known to occur across a range of taxa, however we do not currently understand whether climatic niche shifts can consistently be predicted across multiple introduced ranges. Using three congeneric weed spec...

Pastures represent about half of the global agricultural area and productivity losses from weeds are significant. The complex interactions between them and other pasture plants, livestock and the environment imply a need for innovative research that transforms pasture management. To this end, a horizon scan was conducted to identify relevant issues...

Evolutionary processes which increase the probability of an introduced plant species becoming invasive include high levels of genetic diversity and phenotypic plasticity. Naturalised in New Zealand, monkeyflower, ( Erythranthre gutatta ), a clonally spreading herb of waterways and seepage areas native to the Western USA, shows marked variation in a...

To prevent and effectively manage the socioeconomic and environmental impacts of invasive non-native species it is essential that the underpinning scientific knowledge is widely disseminated and understood by scientists, the public, and other stakeholders. A key need for the public understanding of science is that technical information is easy to r...

Pines (genus Pinus) are cultivated extensively for forestry purposes, particularly in regions that are outside the genus' native range. The most common forestry species are also typically those most likely to escape cultivation and spread rapidly, and thus pines constitute a substantial weed problem in many regions. However, there is limited knowle...

Nature-based management aims to improve sustainable agroecosystem production, but its efficacy has been variable. We argue that nature-based agroecosystem management could be significantly improved by explicitly considering and manipulating the underlying networks of species interactions. A network perspective can link species interactions to ecosy...

Climatic niche shifts occur when species occupy different climates in the introduced range than in their native range. Climatic niche shifts are known to occur across a range of taxa, however we do not currently understand whether climatic niche shifts can consistently be predicted across multiple introduced ranges. Using three congeneric weed spec...

The competition–colonisation trade‐off is recognised as a key mechanism for diversity maintenance, whereby weak competitors can avoid competition with stronger competitors due to their greater dispersal ability. To date, most theoretical and empirical work has focused on trade‐offs among different species yet a within‐species perspective is crucial...

BACKGROUND The number of herbicide‐resistant weeds differs across the globe but the reasons for this variation are poorly understood. Taking a macroecological approach, the role of six drivers of herbicide resistance in a country was examined for barley, maize, rice and wheat crops worldwide. Drivers captured agronomic measures (crop harvested area...

Humans have exchanged plant species beyond their native borders since millennia. The pathways of exchange and their relative importance have differed among regions, times and species. Here, we review the temporal developments of pathways of alien plant species introductions and how these relate to trends in alien plant species richness at a global...

BACKGROUND The number of weed species resistant to multiple herbicide modes of action (MoAs) has increased over the last 30 years and may in the future render existing herbicide MoAs obsolete for many cropping systems. Yet few predictive tools exist to manage this risk. Using a worldwide dataset of weed species resistant to multiple herbicide MoAs,...

Quantifying the spatial extent, location and habitat associations of invasive tree species is critical to predict their future spread and prioritise areas for management. Species–environment relationship analyses are useful tools for understanding and predicting the potential geographical distribution of these species; however, such tools require r...

Pathogen damage is responsible for a considerable reduction in profit to the New Zealand forest industry. An assessment of pathogen prevalence, propagation and production methods, and phytosanitary/biosecurity protocols at the forest nursery level was conducted in order to identify predictor variables for pathogen acquisition and potential spread....

Context dependence is widely invoked to explain disparate results in ecology. It arises when the magnitude or sign of a relationship varies due to the conditions under which it is observed. Such variation, especially when unexplained, can lead to spurious or seemingly contradictory conclusions, which can limit understanding and our ability to trans...

Invasive non‐native species are important drivers of ecosystem change, yet the driving forces of biological invasions themselves are poorly understood. Such information is essential to ensure policies focus on the most relevant drivers, and that future scenarios capture the full range of potential outcomes for invasive non‐native species. I carried...

BACKGROUND Herbicide resistant weeds pose one of the most significant global challenges to sustainable food and fiber production. Plant traits are assumed to play a significant role in determining whether a weed is likely to evolve herbicide resistance but there have been few quantitative assessments to date. There is therefore an urgent need to in...

Seed size and seed number are key functional traits that can affect invasion success and evolve in the introduced range. With finite resources, seed size and number are expected to trade off. If trade‐offs are relaxed in the introduced range, this could promote invasion. Few studies have compared life‐history trade‐offs between ranges, so these dyn...

Scenario analysis has emerged as a key tool to analyze complex and uncertain future socio-ecological developments. However, currently existing global scenarios (narratives of how the world may develop) have neglected biological invasions, a major threat to biodiversity and the economy. Here, we use a novel participatory process to develop a diverse...

Determining population growth across large scales is difficult because it is often impractical to collect data at large scales and over long timespans. Instead, the growth of a population is often only measured at a small, plot‐level scale and then extrapolated to derive a mean field estimate. However, this approach is prone to error since it simpl...

Imports of seeds for sowing are a major pathway for the introduction of contaminant seeds, and many agricultural weeds globally naturalised originally have entered through this pathway. Effective management of this pathway is a significant means of reducing future plant introductions and helps minimise agricultural losses. Using a national border i...

Pine (genus Pinus) species are planted extensively for forestry purposes in areas where they are non‐native, with the result that biological invasions by many of these species are of considerable concern in many regions. Owing to the economic importance of these species, management approaches must focus on reducing the risk that they will spread fr...

Climatic niche shifts occur when species occupy different climates in the introduced range than in their native range. We know that climatic niche shifts are common occurrences, however we do not currently understand whether climatic niche shifts can consistently be predicted across the globe. Using three congeneric weed species, we investigate whe...

Aim The number of alien species has been increasing for centuries world-wide, but temporal changes in the dynamics of their inter-regional spread remain unclear. Here, we analyse changes in the rate and extent of inter-regional spread of alien species over time and how these dynamics vary among major taxonomic groups. Location Global. Time period...

Imports of seeds for sowing are a major pathway for the introduction of contaminant seeds, and many agricultural weeds globally naturalised originally have entered through this pathway. Effective management of this pathway is a significant means of reducing future plant introductions and helps minimise agricultural losses. Using a national border i...

Invasion biology examines species originated elsewhere and moved with the help of humans, and those species’ impacts on biodiversity, ecosystem services, and human well-being. In a globalized world, the emergence and spread of many human infectious pathogens are quintessential biological invasion events. Some macroscopic invasive species themselves...

Aim: Plant invasions pose a serious risk to biodiversity, and living collections in bo- tanic gardens are recognized as a potentially important source of alien plant introduc- tions. However, it is not yet known how the risks from botanic gardens compare with other socioeconomic and environmental factors in influencing the regional distribu- tion o...

Biological invasions are synonymous with international trade. The direct effects of trade have largely been quantified using relationships between imports and the number of alien species in a region or patterns in the global spread of species linked to shipping and air traffic networks. But trade also has an indirect role on biological invasions by...

Phenotypic plasticity is an essential mechanism by which plants respond to changes in their environment, but our understanding of the evolution of plasticity is still limited. Comparing plasticity of introduced alien species across native and introduced provenances can indicate potential evolution of adaptive plasticity. We examined reaction norms...

Why foraging animals sometimes leave patches before consuming all available food items is a key question in behavioural ecology. Abandoning some food would appear to be disadvantageous, yet optimal foraging theory demonstrates that this sometimes optimises energy intake rates. Crossbills Loxia are specialist avian granivores that forage on seeds wi...

Designing and implementing long-term management strategies for chronic biological invasions is amongst the most vexing ecological research problems. Two key challenges to resolving this problem are: (a) integrating science-based and values-based (e.g. spiritual, cultural, economic and ethical) knowledge sources and (b) developing durable knowledge...

The New Zealand flora has a high proportion of endemic species but has been invaded by almost the same number of non-native plant species. To support management of invasive plant species, we provide an updated inventory of New Zealand’s naturalised flora and compare it with the native flora to identify key taxonomic and functional distinctions. We...

Scenario analysis has emerged as a key tool to analyze complex and uncertain future socio-ecological developments. However, current global scenarios (narratives of how the world may develop) have neglected biological invasions, a major threat to biodiversity and the economy. We used a novel participatory process to develop a diverse set of global b...

Unprecedented rates of introduction and spread of non-native species pose burgeoning challenges to biodiversity, natural resource management, regional economies, and human health. Current biosecurity efforts are failing to keep pace with globalization, revealing critical gaps in our understanding and response to invasions. Here, we identify four pr...